United States
Environmental Protection
1=1 m m Agency
EPA/690/R-14/009F
Final
9-16-2014
Provisional Peer-Reviewed Toxicity Values for
Isopropanol
(CASRN 67-63-0)
Superfund Health Risk Technical Support Center
National Center for Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
-------
AUTHORS, CONTRIBUTORS, AND REVIEWERS
CHEMICAL MANAGERS
Harlal Choudhury, DVM, PhD, DABT
National Center for Environmental Assessment, Cincinnati, OH
J. Phillip Kaiser, PhD, DABT
National Center for Environmental Assessment, Cincinnati, OH
DRAFT DOCUMENT PREPARED BY
ICF International
9300 Lee Highway
Fairfax, VA 22031
PRIMARY INTERNAL REVIEWERS
Ambuja Bale, PhD, DABT
National Center for Environmental Assessment, Washington, DC
Susan Makris, MS
National Center for Environmental Assessment, Washington, DC
This document was externally peer reviewed under contract to
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3136
Questions regarding the contents of this document may be directed to the U.S. EPA Office of
Research and Development's National Center for Environmental Assessment, Superfund Health
Risk Technical Support Center (513-569-7300).
-------
TABLE OF CONTENTS
COMMONLY USED ABBREVIATIONS AND ACRONYMS ii
BACKGROUND 1
DISCLAIMERS 1
QUESTIONS REGARDING PPRTVs 1
INTRODUCTION 2
REVIEW OF POTENTIALLY RELEVANT DATA (CANCER AND NONCANCER) 5
HUMAN STUDIES 14
Oral Exposures, Inhalation Exposures, and Other Exposures 14
ANIMAL STUDIES 14
Oral Exposures 14
Inhalation Exposures 25
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS) 34
DERIVATION 01 PROVISIONAL VALUES 47
DERIVATION OF ORAL REFERENCE DOSES 48
Derivation of Subchronic Provisional RfD (Subchronic p-RfD) 48
Derivation of Chronic Provisional RfD (Chronic p-RfD) 54
DERIVATION OF INHALATION REFERENCE CONCENTRATION 57
Derivation of Subchronic Provisional RfC (Subchronic p-RfC) 57
Derivation of Chronic Provisional RfC (Chronic p-RfC) 60
CANCER WOE DESCRIPTOR 63
MODE-OF-ACTION DISCI SSION 64
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES 64
Derivation of Provisional Oral Slope Factor (p-OSF) 64
Derivation of Provisional Inhalation Unit Risk (p-IUR) 65
APPENDIX A. PROVISIONAL SCREENING VALUES 66
APPENDIX B. DATA TABLES 67
APPENDIX C. BMD OUTPUTS 95
APPENDIX D. REFERENCES 101
l
-------
COMMONLY USED ABBREVIATIONS AND ACRONYMS
a2u-g
alpha 2u-globulin
MN
micronuclei
ACGIH
American Conference of Governmental
MNPCE
micronucleated polychromatic
Industrial Hygienists
erythrocyte
AIC
Akaike's information criterion
MOA
mode-of-action
ALD
approximate lethal dosage
MTD
maximum tolerated dose
ALT
alanine aminotransferase
NAG
N-acetyl-P-D-glucosaminidase
AST
aspartate aminotransferase
NCEA
National Center for Environmental
atm
atmosphere
Assessment
ATSDR
Agency for Toxic Substances and
NCI
National Cancer Institute
Disease Registry
NOAEL
no-observed-adverse-effect level
BMD
benchmark dose
NTP
National Toxicology Program
BMDL
benchmark dose lower confidence limit
NZW
New Zealand White (rabbit breed)
BMDS
Benchmark Dose Software
OCT
ornithine carbamoyl transferase
BMR
benchmark response
ORD
Office of Research and Development
BUN
blood urea nitrogen
PBPK
physiologically based pharmacokinetic
BW
body weight
PCNA
proliferating cell nuclear antigen
CA
chromosomal aberration
PND
postnatal day
CAS
Chemical Abstracts Service
POD
point of departure
CASRN
Chemical Abstracts Service Registry
POD[adj]
duration-adjusted POD
Number
QSAR
quantitative structure-activity
CBI
covalent binding index
relationship
CHO
Chinese hamster ovary (cell line cells)
RBC
red blood cell
CL
confidence limit
RDS
replicative DNA synthesis
CNS
central nervous system
RfC
inhalation reference concentration
CPN
chronic progressive nephropathy
RfD
oral reference dose
CYP450
cytochrome P450
RGDR
regional gas dose ratio
DAF
dosimetric adjustment factor
RNA
ribonucleic acid
DEN
diethylnitrosamine
SAR
structure activity relationship
DMSO
dimethylsulfoxide
SCE
sister chromatid exchange
DNA
deoxyribonucleic acid
SD
standard deviation
EPA
Environmental Protection Agency
SDH
sorbitol dehydrogenase
FDA
Food and Drug Administration
SE
standard error
FEV1
forced expiratory volume of 1 second
SGOT
glutamic oxaloacetic transaminase, also
GD
gestation day
known as AST
GDH
glutamate dehydrogenase
SGPT
glutamic pyruvic transaminase, also
GGT
y-glutamyl transferase
known as ALT
GSH
glutathione
SSD
systemic scleroderma
GST
glutathione -S -transferase
TCA
trichloroacetic acid
Hb/g-A
animal blood-gas partition coefficient
TCE
trichloroethylene
Hb/g-H
human blood-gas partition coefficient
TWA
time-weighted average
HEC
human equivalent concentration
UF
uncertainty factor
HED
human equivalent dose
UFa
interspecies uncertainty factor
i.p.
intraperitoneal
UFh
intraspecies uncertainty factor
IRIS
Integrated Risk Information System
UFS
subchronic-to-chronic uncertainty factor
IVF
in vitro fertilization
UFd
database uncertainty factor
LC50
median lethal concentration
U.S.
United States of America
LD50
median lethal dose
WBC
white blood cell
LOAEL
lowest-observed-adverse-effect level
11
-------
FINAL
9-16-2014
PROVISIONAL PEER-REVIEWED TOXICITY VALUES FOR
ISOPROPANOL (CASRN 67-63-0)
BACKGROUND
A Provisional Peer-Reviewed Toxicity Value (PPRTV) is defined as a toxicity value
derived for use in the Superfund Program. PPRTVs are derived after a review of the relevant
scientific literature using established Agency guidance on human health toxicity value
derivations. All PPRTV assessments receive internal review by a standing panel of National
Center for Environment Assessment (NCEA) scientists and an independent external peer review
by three scientific experts.
The purpose of this document is to provide support for the hazard and dose-response
assessment pertaining to chronic and subchronic exposures to substances of concern, to present
the major conclusions reached in the hazard identification and derivation of the PPRTVs, and to
characterize the overall confidence in these conclusions and toxicity values. It is not intended to
be a comprehensive treatise on the chemical or toxicological nature of this substance.
The PPRTV review process provides needed toxicity values in a quick turnaround
timeframe while maintaining scientific quality. PPRTV assessments are updated approximately
on a 5-year cycle for new data or methodologies that might impact the toxicity values or
characterization of potential for adverse human health effects and are revised as appropriate. It is
important to utilize the PPRTV database (http://hhpprtv.ornl.gov) to obtain the current
information available. When a final Integrated Risk Information System (IRIS) assessment is
made publicly available on the Internet (http://www.epa.gov/iris). the respective PPRTVs are
removed from the database.
DISCLAIMERS
The PPRTV document provides toxicity values and information about the adverse effects
of the chemical and the evidence on which the value is based, including the strengths and
limitations of the data. All users are advised to review the information provided in this
document to ensure that the PPRTV used is appropriate for the types of exposures and
circumstances at the site in question and the risk management decision that would be supported
by the risk assessment.
Other U.S. Environmental Protection Agency (EPA) programs or external parties who
may choose to use PPRTVs are advised that Superfund resources will not generally be used to
respond to challenges, if any, of PPRTVs used in a context outside of the Superfund program.
QUESTIONS REGARDING PPRTVs
Questions regarding the contents and appropriate use of this PPRTV assessment should
be directed to the EPA Office of Research and Development's National Center for
Environmental Assessment, Superfund Health Risk Technical Support Center (513-569-7300).
1
Isopropanol
-------
FINAL
9-16-2014
INTRODUCTION
Isopropanol (also known as isopropyl alcohol and 2-propanol) is a colorless, volatile
liquid. It has a sharp, musty alcohol smell, with an odor threshold of about 1 ppm. It is
commonly sold and used as a disinfectant in a 70% aqueous solution (rubbing alcohol).
Isopropanol is also used as a fuel drier/de-icer, as an intermediate in the synthesis of organic
chemicals, as a solvent for oils and resins, and in cosmetics, skin and hair preparations,
pharmaceuticals, perfumes, lacquer formulations, dye solutions, soaps, and window cleaners. It
is miscible in water. The empirical formula for isopropanol is C3H8O (see Figure 1). A list of
physicochemical properties is provided in Table 1.
on
H3c H CH3
Figure 1. Isopropanol Structure
Table 1. Physicochemical Properties of Isopropanol (CASRN 67-63-0)a
Property (unit)
Value
Boiling point (°C)
82
Melting point (°C)
-89.5
Density (g/cm3 at 25°C)
0.785
Vapor pressure (Pa at 25°C)
4,400
pH (unitless)
NA
Solubility in water (g/100 mL at 25°C)
Miscible
Relative vapor density (air =1)
2.1
Molecular weight (g/mol)
60.09
Flash point (°C)
11.7
Octanol/water partition coefficient (unitless)
NA
aValues from IARC (19991 and from ChemicalBook (20081.
NA = not available.
A summary of available toxicity values for isopropanol from U.S. EPA and other
agencies/organizations is provided in Table 2.
2
Isopropanol
-------
FINAL
9-16-2014
Table 2. Summary of Available Toxicity Values for Isopropanol (CASRN 67-63-0)
Source/
Parameter3
Value (Applicability)
Notes
Reference
Date
Accessed
Noncancer
ACGIH
8-h TLV-TWA: 200 ppm (490 mg/m3)
15-min TLV-STEL: 400 ppm (980 mg/m3)
BEI: 40 mg/L
TLV based on eye and upper respiratory tract irritation and central nervous
system effects (i.e., changes in postural sway).
Determinant for the BEI was acetone in urine.
ACGIH
(2013)
NA
ATSDR
NV
NA
ATSDR
(2013)
NA
Cal/EPA
Acute REL: 3.2 x 103 ^g/m3 (3.2 mg/m3)
Chronic REL: 7.0 x 103 ^g/m3 (7.0 mg/m3)
The acute REL hazard index targets are eyes and respiratory system.
The chronic REL hazard index targets are development and kidney.
Cal/EPA
(2014)
NA
NIOSH
10-hREL-TWA: 400 ppm (980 mg/m3)
15-min REL-TWA: 500 ppm (1,225 mg/m3)
IDLH: 2,000 ppm
The IDLH is set at 2,000 ppm, based on 10% of the lower explosive limit,
even though the relevant toxicological data indicates irreversible health
effects or impairment of escape exists only at higher concentrations.
NIOSH
(2010)
NA
OSHA
8-h PEL-TWA: 400 ppm (980 mg/m3)
NA
OSHA (2011)
NA
IRIS
NV
NA
U.S. EPA
9-12-2014
Drinking water
NV
NA
U.S. EPA
(2012a)
NA
HEAST
NV
NA
U.S. EPA
(2011a)
NA
CARA HF.F.P
NV
NA
U.S. EPA
(1994a.
1985)
NA
WHO
NV
NA
WHO
9-12-2014
Cancer
IRIS
NV
NA
U.S. EPA
9-12-2014
HEAST
NV
NA
U.S. EPA
(2011a)
NA
IARC
"Not Classifiable as to its Carcinogenicity to
Humans (Group 3)"
Selection made due to inadequate evidence in humans and experimental
animals.
IARC (1999)
NA
3
Isopropanol
-------
FINAL
9-16-2014
Table 2. Summary of Available Toxicity Values for Isopropanol (CASRN 67-63-0)
Source/
Parameter3
Value (Applicability)
Notes
Reference
Date
Accessed
NTP
NA
NV
NTP (2011)
NA
Cal/EPA
NA
NV
Cal/EPA
(2012)
NA
ACGIH
"Not Classifiable as a Human Carcinogen
(A4 )"
NA
ACGIH
(2013)
NA
aSources: American Conference of Governmental Industrial Hygienists (ACGIH); Agency for Toxic Substances and Disease Registry (ATSDR); California
Environmental Protection Agency (Cal/EPA); National Institute for Occupational Safety and Health (NIOSH); Occupational Safety and Health Administration
(OSHA); Chemical Assessments and Related Activities (CARA); Health and Environmental Effects Profile (HEEP); World Health Organization (WHO); Integrated
Risk Information System (IRIS); Health Effects Assessment Summary Tables (HEAST); International Agency for Research on Cancer (IARC); National Toxicology
Program (NTP).
BEI = biological exposure index; IDLH = immediately dangerous to life or health; NA = not applicable; NV = not available; PEL-TWA = permissible exposure
level-time weighted average; REL = reference exposure levels; REL-TWA = recommended exposure level-time weighted average; TLV-STEL = threshold limit
value-short-term exposure limit; TLV-TWA = threshold limit value-time weighted average.
4
Isopropanol
-------
FINAL
9-16-2014
Literature searches were conducted on sources published from 1900 through March 26,
2014 for studies relevant to the derivation of provisional toxicity values for isopropanol, CASRN
67-63-0. Searches were conducted using U.S. EPA's Health and Environmental Research
Online (HERO) database of scientific literature. HERO searches the following databases:
AGRICOLA; American Chemical Society; BioOne; Cochrane Library; DOE: Energy
Information Administration, Information Bridge, and Energy Citations Database; EBSCO:
Academic Search Complete; GeoRef Preview; GPO: Government Printing Office;
Informaworld; IngentaConnect; J-STAGE: Japan Science & Technology; JSTOR: Mathematics
& Statistics and Life Sciences; NSCEP/NEPIS (EPA publications available through the National
Service Center for Environmental Publications [NSCEP] and National Environmental
Publications Internet Site [NEPIS] database); PubMed: MEDLINE and CANCERLIT databases;
SAGE; Science Direct; Scirus; Scitopia; SpringerLink; TOXNET (Toxicology Data Network):
ANEUPL, CCRIS, ChemlDplus, CIS, CRISP, DART, EMIC, EPIDEM, ETICBACK, FEDRIP,
GENE-TOX, HAPAB, HEEP, HMTC, HSDB, IRIS, ITER, LactMed, Multi-Database Search,
NIOSH, NTIS, PESTAB, PPBIB, RISKLINE, TRI, and TSCATS; Virtual Health Library; Web
of Science (searches Current Content database among others); World Health Organization; and
Worldwide Science. The following databases outside of HERO were searched for relevant
health information: ACGM, AT SDR, Cal/EPA, U.S. EPA IRIS, U.S. EPA HEAST, U.S. EPA
HEEP, U.S. EPA OW, EPA TSCATS/TSCATS2, NIOSH, NTP, OSHA, and RTECS.
REVIEW OF POTENTIALLY RELEVANT DATA
(CANCER AND NONCANCER)
Table 3 provides an overview of the relevant database for isopropanol and includes all
potentially relevant repeat-dose short-term-, subchronic-, and chronic-duration studies.
Reference to "statistical significance" used throughout the document indicates ap-value of
<0.05.
5
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
Human
1. Oral (mg/kg-d)a
Acute0
ND
Short-termd
ND
Long-term6
ND
Chronicf
ND
2. Inhalation (mg/m3)a
Acute0
ND
Short-termd
ND
Long-term0
ND
Chronicf
ND
Animal
1. Oral (mg/kg-d)a
Subchronic
22/0, Wistar SPF rat,
drinking water, 12 wk
0; 870, 1,280,
1,680, 2,520
(Adjusted)
Increased relative liver weight
at >1,680 mg/kg-d, increased
relative kidney weight at
>1,280 mg/kg-d, increased
relative adrenal weight at
>1,680 mg/kg-d, and increased
relative testes weight at
2,520 mg/kg-d.
870 (Adjusted)
554 for
increased
relative
kidney
weight
1,280 (Adjusted)
Pileeaard
and
Ladefosed
(1993)
PR
6
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
Chronic
ND
Developmental
0/20, Wistar-derived rat,
drinking water, GDs 6-16,
sacrificed on GD 20
0, 596, 1,242,
1,605
F0: Decreased maternal food
consumption at >1,242 mg/kg-
d and decreased water intake at
>596 mg/kg-d.
Fl: Decreased male and female
fetal body weight at
1,605 mg/kg-d and decreased
number of fetuses with the
fourth sacral arch at
>596 mg/kg-d.
Maternal:
NDr
Developmental:
NDr
847 for
decreased
fetal body
weight in
male and
female
rats
Maternal:
596
Developmental:
596
BIBRA
(1987)
PR
Developmental
0/64, CD(S-D)BR rat,
gavage, GD 6-PND 21
0, 200, 700,
1,200
F0: One 1,200-mg/kg-d dam
diedonPND 15.
Fl: No observed effects.
Maternal:
700
Developmental:
1,200
DU
Maternal:
1,200 (FEL)
Developmental:
NDr
Bates et al.
(1994)
PR
Developmental
0/25, CD(S-D) rat, gavage
(aqueous), GDs 6-15,
sacrificed on GD 20
0, 400, 800,
1,200
F0: Dam mortality at
>800 mg/kg-d.
Fl: Decreased fetal body
weight in males and females at
>800 mg/kg-d and males and
females combined at
1,200 mg/kg-d.
Maternal:
400
Developmental:
400
513 for
decreased
fetal body
weight in
female
rats
Maternal:
800 (FEL)
Developmental:
800
Tvl et al.
(1994)
PR
7
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
Developmental
0/15, NZW rabbit, gavage
(aqueous), GDs 6-18,
sacrificed on GD 30
0,120, 240,480
F0: Dam mortality at
480 mg/kg-d and decreased
maternal food consumption
at 480 mg/kg-d.
Fl: Decreased fetal body
weight in males only and
males and females combined
at 480 mg/kg-d and in
females only at >240 mg/kg-
d.
Maternal:
240
Developmental:
120
120 for
decreased
fetal
body
weight in
female
rabbits
Maternal:
480 (FEL)
Developmental:
240
Tvl et al.
(1994)
PR, PS
Reproductive
(one-
generation)
10/10, Wistar-derived rat,
drinking water, treatment
initiated 70 d (male) and
21 d (female) prior to
mating with dosing
continued through weaning
ofFl litters onPND 21.
The premating phase refers
to treatment of F0 females
for 21 d prior to mating.
The postpartum phase
refers to treatment of F0
females from PND 1 to
PND 21. Each F0 male
treatment group received
the same doses throughout
the duration of the study.
F0 male
average: 0, 317,
711, 1,001,
1,176 (Adjusted)
F0 female
average
(Adjusted for
postpartum
phase): 0, 1,167,
2,645, 2,825,
2,724
F0 (parental): Decreased body
weight in dams on PND 21 at
2,825 and 2,724 mg/kg-d;
decreased food consumption
and water intake in dams on
PND 21 at 2,825 and
2,724 mg/kg-d; decreased food
consumption and water intake
in males at >711 mg/kg-d;
increased absolute liver and
kidney weights in males at
1,176 mg/kg-d; increased
relative liver and kidney
weights in males at >
1,001 mg/kg-d; increased
absolute liver weight in
females at >2,645 mg/kg-d;
increased absolute kidney
weight and relative liver and
kidney weights in females at
2,825 and 2,724 mg/kg-d.
Fl: Decreased pup weight in
both sexes at >1,167 mg/kg-d.
Parental:
317 (F0 males)
Postpartum
phase: NDr (Fl
pups, both
sexes)
606 for
increased
absolute
liver
weight in
F0 males
Parental:
711 (F0 males)
Postpartum
phase: 1,167 (Fl
pups, both
sexes)
BIBRA
(1986)
NPR; pilot
study
8
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
Reproductive
(one-
generation)
10/30, (10 females for
embryotoxicity; 20 females
for single-generation
[littering]), Wistar-derived
rat, drinking water,
treatment initiated 70 d
(male) and 21 d (female)
prior to mating with dosing
continued through weaning
ofFl litters onPND 21.
The premating phase refers
to treatment of F0 females
for 21 d prior to mating.
The postpartum phase
refers to treatment of F0
females from PND 1 to
PND21.
F0 male average
(Days -3 to 126
Adjusted):
0, 347, 625,
1,030
F0 Female
average
(Adjusted for
premating
phase): 0, 456,
835, 1,206
(Adjusted for
postpartum
phase):
0, 1,053, 1,948,
2,768
F0 (parental): Decreased water
intake in males at
>625 mg/kg-d; decreased water
intake in females at
1,206 mg/kg-d; decreased food
consumption in males at
>347 mg/kg-d; decreased food
consumption in females at
1,206 (premating) and
1,902 (gestation) mg/kg-d;
increased relative liver, spleen,
and kidney weights in males at
1,030 mg/kg-d; increased
relative and absolute liver
weight in females at
2,768 mg/kg-d; increased
absolute kidney weights in
males at 1,030 mg/kg-d.
Parental:
NDr (F0 males)
663 for
increased
relative
liver
weight in
F0 males
Parental:
347
BIBRA
(1988)
PR; parental
(F0)
component of
the BIBRA
(1988) studv.
9
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Number of Male/Female,
Strain Species, Study
BMDL/
Reference
Category
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMCLa
LOAELa
(Comments)
Notesb
Reproductive
0, 668, 1,330,
F0 (parental): Deceased food
Parental:
613 for
Parental:
BIBRA
PR;
(one-
1,902
consumption in females at
1,330 (F0
decreased
1,902 (F0
(1988)
gestational
generation)
1,902 mg/kg-d.
females)
pup body
weight in
females)
component
of the
F1: Decreased pup body
F1 pups: 668
both sexes
F1 pups: 1,330
BIBRA
weight in both sexes on PND 4
(both sexes)
on PND 4
(both sexes)
(1988)
at >1,330 mg/kg-d; decreased
study. Doses
fetal body weight at
forFl pups
1,902 mg/kg-d; increased
are
number of preimplantation
presented
losses at 1,902 mg/kg-d.
assuming
that they
received
100% of the
dose given
to dams.
Reproductive
0, 1,053, 1,948,
F1 pups: Decreased pup body
NDr
580.9 for
1,053
BIBRA
PR;
(one-
2,768
weight in both sexes on
decreased
(1988)
postpartum
generation)
PND 21 at >1,053 mg/kg-d;
increased relative liver weight
in males and females at
2,768 mg/kg-d at ~31 d
postweaning; increased relative
testes weight in males at
2,768 mg/kg-d at ~31 d
postweaning.
pup body
weight in
both sexes
on
PND 21
component
of the
BIBRA
(1988)
study. Doses
forFl pups
are
presented
assuming
that they
received
100% of the
dose given
to dams.
10
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
Reproductive
(two-
generation)
30/30, S-D rat, gavage,
treatment began 10-13 wk
before mating and
continued through lactation
(female) and until the last
litter was sired (male)
0, 100, 500,
1,000 (Adjusted)
F0: Increased absolute and
relative liver weight in males
and increased relative liver
weight in females at
1,000 mg/kg-d.
Fl: Increased relative liver
weight in adult males at
>500 mg/kg-d; increased
relative liver weight in adult
females at 1,000 mg/kg-d;
decreased male mating index at
1,000 mg/kg-d; decreased live
birth index at 1,000 mg/kg-d;
decreased Day 1 (1,000 mg/kg-
d) and Day 4 (>500 mg/kg-d)
survival indices.
F2: Decreased Day 1
(>500 mg/kg-d), Day 4
(1,000 mg/kg-d), and Day 7
(>500 mg/kg-d) survival
indices; decreased lactation
index at >500 mg/kg-d;
decreased male pup body
weight at 1,000 mg/kg-d.
Parental:
100 (Adjusted)
Reproductive:
500 (Adjusted)
Developmental:
100
197 for
increased
relative
liver
weight in
Fl adult
males
Parental:
500 (Adjusted)
Reproductive:
1,000 (Adjusted)
Developmental:
500
Bevan et al.
(1995)
PR;
mortality
was also
observed but
does not
appear to be
dose related.
Carcinogenic
ND
11
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAELa
BMDL/
BMCLa
LOAELa
Reference
(Comments)
Notesb
2. Inhalation (mg/m3)a
Subchronic
25/25, F344 rat, vapor
inhalation for 13 wk,
6 h/d, 5 d/wk (10/10 for
systemic toxicity, and
15/15 for neurobehavioral
assessment)
0,43.9,222,
661.8, 2,198
Mean cumulative motor
activity was increased in
females at 2,198 mg/m3 in
neurobehavioral assessment.
661.8
DU
2,198
Burleish-
Flaver et al.
(1994)
PR, PS
Subchronic
0/30, F344 rat, vapor
inhalation, 9 wk or 13 wk,
6 h/d, 5 d/wk
0, 2,199
Mean cumulative motor
activity was increased.
NDr
DU
2,199
Burleieh-
Flaver et al.
(1998)
PR; the
study was
specifically
designed to
test
neurotoxicity
Subchronic
10/10, CD-I mouse, vapor
inhalation for 13 wk, 6 h/d,
5 d/wk
0, 43.9, 222,
661.8, 2,198
Increased relative liver weight
in females at >661.8 mg/m3.
222
DU
661.8
Burleieh-
Flaver et al.
(1994)
PR
Chronic
ND
Developmental
0/9-15, S-D rat, vapor
inhalation, GDs 1-19,
7 h/d, 7 d/wk
0, 2,516, 5,048,
7,185
F0: No observed effects.
F1: decreased fetal body
weight in males and females at
>5,048 mg/m3; decreased
number of implants and live
implants at 7,185 mg/m3;
increased resorptions at
7,185 mg/m3; increased
malformations at
>5,048 mg/m3.
Maternal:
7,185
Developmental:
2,516
1,907 for
decreased
fetal body
weight in
male rats
Maternal:
NDr
Developmental:
5,048
Nelson et al.
(1988s)
PR
Reproductive
ND
12
Isopropanol
-------
FINAL
9-16-2014
Table 3. Summary of Potentially Relevant Data for Isopropanol (CASRN 67-63-0)
Category
Number of Male/Female,
Strain Species, Study
Type, Study Duration
Dosimetry3
Observed Effects
NOAEL3
BMDL/
BMCL3
LOAEL3
Reference
(Comments)
Notesb
Carcinogenic/
Chronic
75/75, F344 rat, vapor
inhalation, exposed for at
least 104 wk, 6 h/d, 5 d/wk;
interim sacrifice of
10 animals/sex/concentratior
n group at Wk 72
0, 221, 1,101,
2,211
Increased mortality in males at
2,211 mg/m3; increased relative
liver weight in males at
1,101 mg/m3; increased relative
liver weight in females at
2,211 mg/m3; increased
incidence of microscopic
kidney damage in males and
females at 2,211 mg/m3.
Systemic:
221
262 for
increased
relative
liver
weight in
male rats
Systemic:
1,101
Burleieh-
Flaver et al.
(1997)
PR, PS
Carcinogenic/
Chronic
75/75, CD-I mouse vapor
inhalation, exposed for at
least 78 wk, 6 h/d, 5 d/wk;
interim sacrifice of
10 animals/sex/concentrati
on group at Wk 54
Additional recovery group
(10
animals/sex/concentration
group) not exposed after
Wk 53, sacrificed at
Wk 78
0, 221,1,101,
2,211
Increased relative liver
weight in females at
2,211 mg/m3; decreased
absolute and relative testes
weights in males at
>221 mg/m3; increased
incidence of seminal vesicle
enlargement in males at
2,211 mg/m3; increased
incidences of adrenal gland
congestion, mucosal cell
hyperplasia in the stomach,
splenic hematopoiesis, and
hemosiderosis in females at
2,211 mg/m3.
Systemic:
NDr
1,181 for
increased
relative
liver
weight in
female
mice
Systemic:
221
Burleish-
Flaver et al.
(1997)
PR
aDosimetry: NOAEL, BMDL/BMCL, and LOAEL values are converted to an adjusted daily dose (ADD in mg/kg-d) for oral noncancer effects and a human equivalent
concentration (HEC in mg/m3) for inhalation noncancer and carcinogenic effects. All long-term exposure values (4 wk and longer) are converted from a discontinuous to a
continuous exposure. Values from animal developmental studies are not adjusted to a continuous exposure.
HED = animal dose (mg/kg-d) x (BWa ^ BWh)1/4
HECexresp = ppm x (MW ^ 24.45) x (hper d exposed ^ 24) x (d per wk exposed ^ 7) x blood gas partition coefficient.
bNotes: IRIS = Utilized by IRIS; date of last update; NPR = not peer reviewed; PR = peer reviewed; PS = principal study.
0 Acute = Exposure for 24 h or less (U.S. EPA. 2002).
dShort-term = Repeated exposure for > 24 h < 30 d (U.S. EPA. 2002).
"Long-term = Repeated exposure for > 30 d < 10% lifespan (based on 70 yr typical lifespan) (U.S. EPA. 2002).
fChronic = Repeated exposure for >10% lifespan (U.S. EPA. 2002).
DU = data unsuitable; FEL = frank effect level; GD = Gestation Day; ND = no data; NDr = not determined; NS = not selected; NZW = New Zealand White; PND = Postnatal
Day; S-D = Sprague-Dawley.
13
Isopropanol
-------
FINAL
9-16-2014
HUMAN STUDIES
Oral Exposures, Inhalation Exposures, and Other Exposures
Although there were no human studies suitable for reference value derivation, there are
several published case reports that are briefly summarized in Table 5 below.
ANIMAL STUDIES
Oral Exposures
The effects of oral exposures to isopropanol in animals have been evaluated in one
subchronic-duration neurotoxicity study (Pilegaard and Ladefoged. 1993). four developmental
studies (Bates et al.. 1994; Tyl et al.. 1994; BIBRA. 1987). and three reproductive studies
(BIBRA. 1988. 1986) [pilot study]; (Bevan et al.. 1995). These study reports are articles
published in peer-reviewed journals and/or performed in compliance with Good Laboratory
Practice (GLP) requirements. Chronic-duration and carcinogenicity oral studies with
isopropanol have not been identified. Tyl et al. (1994) is a journal article containing studies
performed on two different species (rat and rabbit).
Subchronic-duration Studies
Pilegaard andLadefoged (1993)
Pilegaard and Ladefoged (1993) reported on an investigation of the subchronic toxicity
and neurotoxicity of isopropanol in rats after administration in drinking water. Male Wistar
SPF rats were separated into five groups of 22 rats each. Isopropanol in drinking water was
administered at 0 (control), 1, 2, 3, or 5% (0, 870, 1,280, 1,680, and 2,520 mg/kg-day) for
12 weeks. Purity and formulated dose stability were not reported. In the high-dose group
(2,520 mg/kg-day), water intake was low during Week 1; the amount of isopropanol was reduced
to 4% during Week 2 and returned to 5% for the remainder of the study. Animals were
sacrificed on Day 90. Twelve animals per group were decapitated and submitted for
pathological examination. The liver, heart, spleen, testes, kidneys, and adrenals were weighed,
and organ specimens were prepared and stained appropriately for histopathological examination.
The remaining 10 animals per group were transcardially perfused with 4% neutral buffered
formaldehyde and submitted for brain tissue densitometry. A section of the right hemisphere
containing the dorsal hippocampus was removed, embedded in paraffin, and cut into serial
sections. Random sections were selected for immunohistochemical staining for glial fibrillary
acidic protein (GFAP). Densitometric measurements in several regions of each section (CA1,
CA3, and hilar), as well as section thickness measurements, were performed.
Pilegaard and Ladefoged (1993) noted statistically significant decreases in body weight
in the 1,680- and 2,520-mg/kg-day isopropanol groups, and body weight was increased in the
870-mg/kg-day group compared to control (numerical body-weight data and level of significance
were not reported). Relative water intake was lower (statistical significance unknown) in the
1,280-, 1,680-, and 2,520-mg/kg-day isopropanol groups initially, and one rat died in the
2,520-mg/kg-day group. Statistically significant dose-dependent increases were observed in
relative (to body) liver weight in the 1,280-mg/kg-day group (9%), the 1,680-mg/kg-day group
(11%), and the 2,520-mg/kg-day group (12%); in relative kidney weight in the 1,280- to
2,520-mg/kg-day groups (20-35%), and in relative adrenal weight in the 1,680 and
2,520 mg/kg-day groups (27-34%). Relative testes weight was also statistically significantly
increased at 2,520 mg/kg-day (13%) (see Table B-l). The study authors reported dose-related
increases in hyaline cast and hyaline droplet formation in the renal proximal tubules in the males
14
Isopropanol
-------
FINAL
9-16-2014
at >1,280 mg/kg-day; however, no incidence or severity data were provided. No abnormalities
were observed in the other examined organs. No differences in absorbance in the CA1, CA3,
and hilar regions of the dorsal hippocampus due to isopropanol exposure were observed (see
Table B-l). No neurotoxic effect of isopropanol on the dorsal hippocampus was observed in this
study according to the densitometric method used. A LOAEL of 1,280 mg/kg-day is identified
from this study based on increased relative kidney weight with a corresponding NOAEL of
870 mg/kg-day.
Chronic-duration Studies
No studies were identified.
Developmental Studies
BIBRA (1987)
The non-peer-reviewed technical report by BIBRA (1987) was not publically available;
however, limited results from the report were published in a peer-reviewed journal (Faber et al..
2008). BIBRA (1987) conducted a GLP-compliant developmental study in rats as part of a
series of studies for the Feed and Drink Federation IPA Steering Group (London, UK). Virgin
male and female Wistar-derived rats were obtained from Olac 1976 Ltd. and acclimated for at
least 1 week prior to study initiation. Animals were maintained on a 12:12 hour light:dark cycle
at a temperature and humidity of 20-24°C and 45-65%. Prior to mating, the animals were group
housed, by sex, in polypropylene cages with stainless steel tops and grid floors; animals had
access to Certified Rat and Mouse No. 3 feed (Special Diet Services) and domestic mains tap
water ad libitum. Female and male rats, 11-12 weeks of age, were paired overnight until
successful mating occurred: the presence of sperm in the vagina or a vaginal plug defined
Gestation Day (GD) 0. Mated females were housed singly, as previously described, and
randomly assigned to one of the four dose groups (n = 20/group).
The isopropanol utilized in the BIBRA (1987) study was provided by Shell Chemicals
UK Ltd. (batch 1 Al/41.3/84 GB1/260) and had a purity of 99.89% according to gas-liquid
chromatography (GLC). Drinking water formulations were prepared with domestic mains tap
water at intervals of 2 weeks or less and analyzed by GLC to confirm isopropanol concentration
and stability. All formulations were within ±10% of nominal concentrations and stable for at
least 28 days. Isopropanol drinking water concentrations presented to dams in the developmental
study were 0%, 0.5%, 1.25%, or 2.5% (0, 596, 1,242, or 1,605 mg/kg-day) on GDs 6-16.
Isopropanol intake was calculated from body weight and water intake data, and the actual dose
concentrations. General observations were made daily, with thorough clinical observations
conducted weekly. Maternal body weights, food consumption, and water intake were
determined daily (GDs 0-20), and dams were euthanized on GD 20. The abdominal and
thoracic contents were examined for abnormalities. The ovaries were examined and the number
of corpora lutea recorded. The uterus was examined, and the numbers and locations of viable
and nonviable fetuses, early and late resorptions, total implantations, and pre- and
postimplantation losses were recorded. Live fetuses were weighed and examined for gross
abnormalities. Approximately 50% of all of the fetuses (including all with gross abnormalities)
were preserved in ethanol, eviscerated, and processed for skeletal examination after staining with
Alizarin Red S. The stained preparations were examined for skeletal abnormalities, variants, and
variations in the degree of ossification. The remaining fetuses were preserved in Bouin's
solution; the high-dose and control groups were examined by freehand sectioning of the head and
palate and dissection of the abdomen and thorax. The sex was determined and recorded.
15
Isopropanol
-------
FINAL
9-16-2014
Continuous variables (maternal and fetal weights, intakes, and the total number of resorptions,
pre- and postimplantation losses, and live fetuses) were compared with analysis of variance
(ANOVA) and least-square difference and Student's Mest procedures. Incidences of maternal
abnormalities, and fetal skeletal and visceral abnormalities (accounting for both between and
within litter variation), were compared with Fisher's Exact tests.
The BIBRA (1987) study reported no deaths, abortions, or early deliveries for the
females, and the numbers of nonpregnant females were distributed across the dose groups in a
nontreatment-related manner. Food consumption was statistically significantly reduced relative
to control levels in the 1,242- and 1,605-mg/kg-day groups during the dosing period (high dose,
GDs 6-16; mid dose, GDs 6-9). Water intake was statistically significantly decreased at
>596 mg/kg-day. Food consumption and water intake in these groups rebounded after GD 16 to
levels greater than or similar to control; intake levels in the low-dose group (596 mg/kg-day)
were similar to the control throughout the study. Dams in the high-dose group lost weight
(GDs 6-8) and had a lower rate of body-weight gain through GD 16; body-weight gain was
greater than control during GDs 17-20 in the high-dose dams, but overall body weights
remained lower through GD 20. Table B-2 summarizes the litter parameters and fetal weights,
including endpoints for events that occurred prior to isopropanol exposure (pregnancy rate, total
number of corpora lutea, and total numbers of preimplantation loss). No effects related to
isopropanol exposure in postimplantation loss, mean number of implantation sites, or live fetuses
were observed. Findings included a slight dose-dependent decrease in mean litter weight (not
statistically significant) and a statistically significant decrease in mean fetal weight in the 1,242
and 1,605 mg/kg-day dose groups. Mean fetal body weight was statistically significantly
decreased at 1,605 mg/kg-day. No gross abnormalities were observed; the only skeletal
malformation was an absence of caudal vertebrae and short forelimb and hindlimb bones in a
single control fetus. Statistically significant increases in skeletal variations were indicative of a
lower degree of ossification in the treated animals. The study noted dose-dependent decreases in
the number of fetuses with the fourth sacral arch and dose-dependent increases in the number of
fetuses with less than two caudal arches. Increased numbers of fetuses with small, absent, or
incompletely ossified sternebrae also indicated statistically significantly reduced ossification at
1,605 mg/kg-day. Other statistically significant skeletal findings were not dose dependent. No
abnormalities were noted in the viscera of offspring in the 1,605-mg/kg-day dose group
compared to the control group. A maternal LOAEL of 596 mg/kg-day is identified based on
decreased water intake. A developmental LOAEL of 596 mg/kg-day is identified based on
decreased number of fetuses with the fourth sacral arch. Because 596 mg/kg-day is the lowest
dose tested, neither a maternal nor developmental NOAEL can be identified.
Bates et al. (1994)
In a developmental neurotoxicity study, Bates et al. (1994) administered isopropanol via
gavage to CD (S-D)BR rats. Aqueous dosing solutions of isopropanol were formulated at 0, 40,
140, or 240 mg/mL (0, 200, 700, or 1,200 mg/kg-day in a dose volume of 5 mL/kg). Two
hundred fifty-six sperm-positive female animals were randomized into four groups (64 rats per
group). Doses were administered from GD 6 through Postnatal Day (PND) 21. Pups were
counted, weighed, and sexed on PNDs 0 and 4, after which standard litter sizes were achieved
(4:4 or 5:3) through culling, with other animals removed from the study. Offspring were
weighed through PND 68 and randomized into male:female pairs for behavioral testing or
neuropathological assessment. Three pairs of pups/litter were evaluated for motor activity
16
Isopropanol
-------
FINAL
9-16-2014
(figure-eight maze), auditory startle response (120-dB tone), or learning/memory (active
avoidance test) in one pair per test on PNDs 13, 17, 21, 47, and 58. Body, liver, and kidney
weight, and implantation site evaluations were performed on all dams after sacrifice on PND 22.
On PNDs 22 and 68, a male and a female pup from each litter (n= 12) were sacrificed and
weighed, and central and peripheral nervous system tissues were prepared for histopathological
evaluation. Brains of all remaining animals were removed after euthanization, weighed, and
examined.
Bates et al. (1994) noted that all pregnant dams gave birth to litters, and the majority of
litters within each dose group had a sufficiently balanced pup sex ratio (n = 26-31). Although
only approximately one-half of the mated animals became pregnant, the study authors did not
attribute this to a treatment effect because treatment began after mating had occurred. In
addition, no treatment-related effects were observed in maternal weight or weight gain, gestation
duration, or food consumption, and no effects were noted in pup weight, weight gain, sex ratio,
development, or survival. Finally, no treatment-related effects were observed in the pup
behavioral tests, maternal organ weights, brain region weights, or in the nervous system
histopathological examinations. The only treatment-related effect of note was death of a single
dam in the 1,200-mg/kg-day group on PND 15. The maternal NOAEL is 700 mg/kg-day. A
maternal LOAEL could not be determined because the next highest dose (1,200 mg/kg-day)
resulted in death. Therefore, 1,200 mg/kg-day is considered a frank effect level (FEL). A
developmental NOAEL of 1,200 mg/kg-day is identified based on a lack of observed
developmental effects; identification of a developmental LOAEL is precluded.
Tyl et al. (1994)
In a developmental toxicity study in the rat, Tyl et al. (1994) examined the developmental
toxicity of isopropanol in orally dosed timed-pregnant female CD (S-D) rats (Charles River
Laboratories, Inc.). Dosing solutions of isopropanol (99.95 ± 0.01% pure) were formulated in
deionized/distilled water at 0, 80, 160, and 240 mg/mL (0, 400, 800, and 1,200 mg/kg-day at a
dose volume of 5 mL/kg) with stability determined for at least 49 days refrigerated. One
hundred sperm-positive female animals (214-275 g in weight and 10 weeks old at GD 0) were
used. The animals were housed singly in polycarbonate cages with stainless steel wire lids and
purified cage litter. Food and deionized/filtered water were available ad libitum, and a
12:12 hour light:dark cycle was maintained. Animals were randomized into one of four groups
(three treatment and a deionized/distilled water vehicle control, 25 per group) to achieve uniform
mean body weight across groups. Aqueous solutions of test article or vehicle alone were
administered by gavage from GDs 6-15. Clinical observations were conducted at least once
daily prior to dosing initiation (GDs 0-5) and post-treatment (GDs 16-20) and twice daily
during the dosing period (GDs 6-15). Body weights and food consumption were recorded on
GDs 0, 6, 9, 12, 15, 18, and 20. Maternal animals were euthanized by CO2 asphyxiation on
GD 20, and thoracic and abdominal organs and cavities were examined. Body, liver, and uterine
weights were recorded, ovarian corpora lutea were counted, and uterine implantation site status
was recorded. Rat fetuses were weighed, sexed, and examined for external alterations. Half of
the fetuses in each litter were decapitated and further examined for visceral alterations, with the
heads examined for soft tissue craniofacial alterations. Fetuses were also examined for skeletal
malformations and variations.
17
Isopropanol
-------
FINAL
9-16-2014
Tyl et al. (1994) reported that pregnancy rate in the rat was high (96%). The three deaths
that occurred after the dosing period (GDs 16 to 18) were considered to be treatment related by
the study authors (l/25[4%] and 2/25 [8%] in the 800-mg/kg-day and 1,200-mg/kg-day dose
groups). Maternal body and liver weights and food consumption were statistically equivalent
across all groups at all time points measured, except for a statistically significant reduction in
maternal weight gain in the 1,200-mg/kg-day group for GDs 0-20 (89.9% of control). This
decrease may be accounted for by reduced fetal body weights in this group. No maternal
necropsy observations appeared treatment related. All pregnant animals had one or more live
fetuses (no resorptions), and all gestational parameters were equivalent across all groups with no
late fetal deaths. The number and sex ratio of live fetuses were also equivalent.
Body weights per litter were statistically significantly reduced at >800 mg/kg-day in male
and female fetuses (see Table B-3). Fetal body weights per litter in all rats (males and females
combined) were statistically significantly decreased at 1,200 mg/kg-day. Fetal variations were
distributed across all groups, with no treatment-related changes observed during external,
visceral, or skeletal examinations. The study authors concluded that isopropanol was not
teratogenic after gavage administration during major organogenesis in the CD rat. A maternal
LOAEL is not determined because of mortality in the dams at the two highest doses. Thus, a
maternal FEL of 800 mg/kg-day with a corresponding NOAEL of 400 mg/kg-day are identified.
A developmental LOAEL of 800 mg/kg-day is identified based on decreased male and female
fetal body weight (>5% change compared to control values) with a corresponding NOAEL of
400 mg/kg-day.
Tyl et al. (1994)
The developmental study in rabbits conducted by Tyl et al. (1994) is selected as the
principal study for deriving the subchronic provisional reference dose (p-RfD) and chronic
p-RfD. This study was conducted according to GLP regulations (RTI. 1990) and examined the
developmental toxicity of isopropanol in the New Zealand White (NZW) rabbit (Hazleton
Research Products, Inc.). Dosing solutions of isopropanol (99.95 ± 0.01% pure) were formulated
in deionized/distilled water at 0, 60, 120, or 240 mg/mL (0, 120, 240, or 480 mg/kg-day at a dose
volume of 2 mL/kg), with stability determined to be least 49 days under refrigeration. Measured
nominal concentrations of dose formulations ranged from 97-106%). Sixty artificially
inseminated female animals (2,750 to 3,800 g in weight and approximately 5.5 months old at
GD 0) were used. The animals were housed singly in stainless steel cages with mesh flooring.
Food and deionized/filtered water were available ad libitum, and a 12:12 hour light:dark cycle
was maintained. Animals were randomized into one of four groups (three treatment and a
deionized/distilled water vehicle control, 15 per group) to achieve uniform mean body weight
across groups. The dosing solutions were administered by gavage from GDs 6-18. Clinical
observations were recorded once daily prior to initiation of treatment (GDs 0-5) and following
the treatment period (GDs 19-30) and twice daily during treatment (GDs 6-18). Body weights
and food consumption were recorded on GDs 0, 6, 9, 12, 15, 18, 21, 24, and 30. Maternal
animals were euthanized on GD 30, and thoracic and abdominal organs and cavities were
examined. Body, liver, uterine weights, and uterine implantation site status (implantations,
resorptions, and live and dead fetuses) were recorded, and ovarian corpora lutea were counted.
Fetuses were weighed and examined for external alterations. Fifty percent of the fetuses were
then sacrificed, sexed internally, and examined for visceral alterations. Fetuses were also
examined for skeletal malformations, and heads were examined for soft tissue craniofacial
18
Isopropanol
-------
FINAL
9-16-2014
alterations. General linear models (GLM) procedures were used to test for significant linear
trends for all analyses of variance; significant effects were further examined by William's and/or
Dunnett's multiple comparison tests. Nominal scale measures were analyzed by %2 test for
independence, with significant differences examined with a one-tailed Fisher's exact probability
test.
Tyl et al. (1994) reported that the pregnancy rate in the rabbit was high (96.7%) in this
study. The four deaths that occurred during or immediately after the dosing period (GDs 11-19)
were considered treatment related (4/15, 27%, in the 480-mg/kg-day group); however, the study
authors provided no further details regarding the cause(s) of the deaths. Maternal body weights
were statistically equivalent across all groups at all time points measured, although body-weight
change was statistically significantly reduced in the 480-mg/kg-day group during the treatment
period (GDs 6-18, 45%). This decrease was associated with a statistically significant reduction
in maternal food consumption during the same period. Gravid uterine and liver weights were
equivalent across all groups. General treatment-related clinical observations were noted at
480 mg/kg-day, including flushed ears, and various nonspecific indicators of stress. No maternal
necropsy observations appeared treatment related. All pregnant animals had one or more live
fetuses (no resorptions), and all gestational parameters were equivalent across all groups. The
number and sex ratio of live fetuses were equivalent between groups, with only slight weight
reductions noted (not statistically significant). There were also decreases in fetal body weight
per litter, albeit not statistically significant (see Table B-4). Female fetal body weight was
decreased (>5% change compared to control values) at >240 mg/kg-day. Fetal body weight in
all rabbits (males and females combined) and male rabbits alone was decreased (>5% change
compared to control values) at 480 mg/kg-day. Fetal variations were distributed across all
groups, with no treatment-related changes observed during external, visceral, or skeletal
examinations; therefore, the study authors concluded that isopropanol was not teratogenic after
gavage administration during major organogenesis in the NZW rabbit. A maternal LOAEL is
not available because the 480 mg/kg-day dose is an FEL in the dams with a corresponding
NOAEL of 240 mg/kg-day. A developmental LOAEL of 240 mg/kg-day is identified based on
decreased female fetal body weight (>5% change compared to control values) with a
corresponding NOAEL of 120 mg/kg-day.
Reproductive Studies
BIBRA (1986)
A one-generation reproductive toxicity pilot study with isopropanol was conducted
according to international GLP regulations by (BIBRA. 1986) in response to the U.S. Toxic
Substances Control Act (TSCA) (not peer reviewed). Dosing solutions of isopropanol were
formulated in domestic tap water at concentrations of 0 (control), 0.5, 1.25, 2.0, and 2.5%. This
study used the Wistar-derived rat (10 male and 10 female animals/group), aged 7-8 weeks. The
test solutions were administered over the following periods: males were administered the test
article 70 days before mating, during mating, and up until sacrifice; females received the test
article 21 days before and during mating, during gestation, rearing of offspring, and up until
sacrifice; and offspring were administered the test article during rearing and up until sacrifice.
The overall intake of isopropanol for male animals over the 18 weeks of treatment was 317, 711,
1,001, or 1,176 mg/kg-day. The intake values for females in the 3-week premating phase were
517, 1,131, 1,330, and 1,335 mg/kg-day, and 1,167, 2,645, 2,825, and 2,724 mg/kg-day in the
3-week postpartum phase of the study. Isopropanol intake during the premating and postpartum
phases was calculated by the study authors using body weight data, water intake data, and the
19
Isopropanol
-------
FINAL
9-16-2014
nominal dose concentrations. However, isopropanol intake, food consumption, and water intake
were not determined for either sex during the mating period, nor were they determined during the
gestational period for the female rats. The animals' weights were recorded throughout the study,
and food consumption and water intake was monitored by weight during the study. At Day 70
(male) or Day 21 (female) after treatment initiation, one female was housed with one male from
the same treatment group for 15 days. Litters were examined on PND 1 (the morning after birth)
for any stillborn or abnormal young and examined on PNDs 4, 7, 10, 14, 17, and 21 for number
of survivors and abnormalities. Each litter was observed daily; the sex of each pup was recorded
on PND 21. Within 7 days of rearing of the last litter, each adult animal was fasted overnight
and sacrificed by exsanguination under anesthesia, and a postmortem examination for
macroscopic abnormalities was performed. The weights of the liver and kidneys were recorded.
Blood was taken from the aorta and analyzed for total erythrocyte and leukocyte counts,
hemoglobin concentration, and mean cell volume. The hematocrit value also was calculated.
All pups were sacrificed at PND 21, but no further information was reported.
BIBRA (1986) reported that body weights of male animals administered 1,001 and
1,176 mg/kg-day isopropanol in the drinking water were statistically significantly decreased by
6% compared to control animals during the first week of treatment. No significant difference in
male body weights were observed for the remainder of the study. Rats administered isopropanol
at concentrations of >711 mg/kg-day in males, and 1,330/1,335 mg/kg-day (premating) and
2,825/2,724 mg/kg-day (postpartum) in females, had statistically significantly reduced food
consumption immediately following administration of the test article, with reductions
statistically significantly lower in both sexes intermittently during treatment. The administration
of drinking water containing >711 mg/kg-day in males, and >1,131 mg/kg-day (premating) and
2,724 mg/kg-day (postpartum) in females, resulted in an immediate statistically significant and
dose-related decrease in water intake. Generally, the water intake during the scheduled
assessments for males and premating females was statistically significantly reduced, as were
overall mean values. Postpartum observations in female animals indicated generally statistically
significant reductions in body weight (5-13% and 13-20% in the 2,825- and 2,724-mg/kg-day
dose groups, respectively) (see Table B-5). Food consumption and water intake were
statistically significantly decreased in females administered isopropanol at concentrations of
2,825 and 2,724 mg/kg-day, with occasional decreases in the 2,645-mg/kg-day group (see
Table B-5). Although fertility (100%) and the number of litters were not adversely affected by
isopropanol treatment, the mean number of pups per litter and mean pup survival per litter were
decreased (statistical significance unknown) at isopropanol concentrations of 1,330 and
1,335 mg/kg-day (premating) and 2,825 and 2,724 mg/kg-day (postpartum) in females; (see
Table B-6). Mean pup weight was decreased (>5% change compared to control values) at
>1,167 mg/kg-day and statistically significantly decreased at >2,645 mg/kg-day. Females
administered 1,330 and 1,335 mg/kg-day (premating) and 2,825 and 2,724 mg/kg-day
(postpartum) had dose-related decreases in red blood cell number (statistically significant),
hematocrit, and hemoglobin concentration, although significant differences varied between
parameters (and decreases in the high-dose concentration group were only 9 to 12% less than
control values). Male animals had a small, not dose-dependent, statistically significant increase
(3-5%>) in mean cell volume in groups receiving >711 mg/kg-day isopropanol. Mean absolute
liver and kidney weights (and organ weights relative to body weight) were generally statistically
significantly increased for both sexes in the two highest dose groups (see Table B-7), although
no differences in terminal body weight due to treatment were noted. Absolute liver and kidney
20
Isopropanol
-------
FINAL
9-16-2014
weights were statistically significantly increased in males at 1,176 mg/kg-day. Absolute liver
weight was statistically significantly increased in females at >2,645 mg/kg-day and absolute
kidney weight was statistically significantly increased in females at 2,825 and 2,724 mg/kg-day.
Statistically significant increases in relative liver weight in the two high-dose isopropanol
treatment groups in males are calculated as 12 and 14%, respectively, and 25 and 21% in
females, respectively. Statistically significant increases in relative kidney weight in the two
high-dose isopropanol treatment groups in males are calculated as 13 and 15%, respectively, and
25 and 21% in females, respectively. No histopathological examination of these organs was
conducted. A parental (F0) LOAEL of 711 mg/kg-day based on decreased food consumption
and water intake is identified in male rats with a corresponding NOAEL of 317 mg/kg-day.
During the postpartum period, a LOAEL of 1,167 mg/kg-day is identified based on decreased F1
pup body weight (>5% change compared to control values). Identification of a NOAEL is
precluded because 1,167 mg/kg-day is the lowest dose tested during the postpartum period.
BIBRA (1988)
As part of a series of studies conducted for the Feed and Drink Federation IP A Steering
Group (London, UK), BIBRA (1988) conducted a non-peer-reviewed, one-generation
reproduction/embryotoxicity study. This study complied with GLP regulations and was reported
in a peer-reviewed article by Faber et al. (2008). Virgin male and female Wistar-derived rats
were obtained from Olac 1976 Ltd. and acclimated for at least 1 week prior to study initiation.
Animals were maintained on a 12:12 hour-light:dark cycle at a temperature and humidity of
20-24°C and 45-65%). Prior to mating, the animals were group housed, by sex, in
polypropylene cages with stainless steel tops and grid floors; animals had access to Certified Rat
and Mouse No. 3 feed (Special Diet Services) and domestic mains tap water ad libitum. Each
dose group consisted of 10 males and 30 females (10 females for embryotoxicity determinations
and 20 females for the littering/reproduction phase). Treatment was initiated 70 days (male,
7-8 weeks of age) and 21 days (female, 10-11 weeks of age) prior to mating. During the mating
period, two females from animals assigned to the littering phase and one female assigned to the
embryotoxicity phase were housed with one male from the same treatment group for up to
15 days. The females were examined every morning until successful mating occurred: the
presence of sperm in the vagina or a vaginal plug defined GD 0. Mated females were housed
singly, as previously described, except for females assigned to the littering phase that had cages
with solid floors with sawdust and nesting materials as needed.
The isopropanol utilized in the BIBRA (1988) was provided by Shell Chemicals UK Ltd.
(batch 1 Al/41.3/84 GB1/260), with a purity of 99.89%) according to GLC. Drinking water
formulations were prepared with domestic tap water at intervals of <2 weeks and were analyzed
by GLC to confirm isopropanol concentration and stability. All formulations were within ±10%
of nominal concentrations, and stable for at least 28 days. Isopropanol drinking water
concentrations presented to dams in the one-generation reproduction/embryotoxicity study were
0%>, 0.5%), 1.0%, or 2.0%) (males: 0, 383, 686, or 1,107 mg/kg-day during premating and 0, 347,
625, or 1,030 mg/kg-day for the full study period (Days -3 to 126); females: 0, 456, 835, or
1,206 mg/kg-day during premating; 0, 668, 1,330, or 1,902 mg/kg-day during gestation; and 0,
1,053, 1,948, or 2,768 mg/kg-day during the postpartum period). Isopropanol intake was
calculated by the study authors from body weight and water intake data with the nominal dose
concentrations.
21
Isopropanol
-------
FINAL
9-16-2014
General observations were made daily during the BIBRA (1988) study, with more
thorough examinations conducted weekly. Body weights of male rats were recorded 3 days prior
to and 4 days after the initiation of treatment, and then twice weekly throughout the study.
Females were weighed daily 3 days prior to and 4 days after treatment was started, and then
twice weekly for 3 weeks. During gestation, females were weighed on GD 0 and every day until
they littered or were euthanized. During lactation, the weight of the female and the total litter
weight were recorded on PNDs 1, 4, 7, and 14. On PND 21, the dams and each of the pups were
weighed individually. Food consumption and water intake were determined at the same intervals
as the body-weight measurements, except for the females during the postpartum period when
consumption/intake of food and water was measured twice weekly. Males were euthanized on
Day 126 of the study, and dams assigned to the embryotoxicity phase of the study were
euthanized on GD 19. The abdominal and thoracic regions were examined for abnormalities, the
ovaries were examined, and the number of corpora lutea were recorded. The uterus was
examined, and the numbers and locations of viable and nonviable fetuses, early and late
resorptions, total implantations, and pre- and postimplantation losses were recorded. Live
fetuses were weighed and examined for gross abnormalities. All fetuses from the embryotoxicity
phase were preserved in ethanol. The viscera of fetuses, and littermates, which showed evidence
of edema in the embryotoxicity study, were examined by evisceration under a dissecting
microscope, and the sex of each fetus was recorded. The remaining females were allowed to
litter. Litters were examined on PND 1 for stillborn or abnormal young, and then daily for any
subsequent deaths. Survivors and additional abnormalities were recorded on PNDs 4, 7, 10, 14,
17, and 21, after which pups were weaned and removed from the dams. Approximately 21 days
after weaning the last litter, each adult animal and one pup/sex/litter were fasted overnight and
euthanized by exsanguination under anesthesia. Blood was collected from the aorta of each adult
for analysis of total erythrocyte and leukocyte counts, hemoglobin concentration, and mean cell
volume. Twelve females (five controls, three in the mid-dose group, and four in the high-dose
group) that failed to litter were euthanized 24 days after the last day of pairing. Adrenal glands,
brain, cecum, gonads, heart, liver, kidney, and spleen weights were recorded. The following
tissues were preserved in 10% neutral buffered formalin for histopathologic examination in the
control and high-dose adult animals: bladder, cervix and uteri, epididymides, ovaries, pituitary,
prostate, seminal vesicles, testes, uterine horns, and vagina. Approximately 10 days later, the
remaining pups (F1 generation) were euthanized by carbon dioxide inhalation and examined for
gross, external abnormalities. The liver and kidneys were weighed, and tissue samples were
preserved in formalin. Statistical analyses were similar to those described previously for the
developmental study by BIBRA (1987).
The BIBRA (1988) study reported that no deaths, abortions, or early deliveries occurred
during the study, and the numbers of nonpregnant females were distributed across the dose
groups in a nontreatment-related manner. Mean water intake was statistically significantly
decreased in males at >625 mg/kg-day, and food consumption was statistically significantly
decreased in males at >347 mg/kg-day. Mean water intake volumes in the high-dose females
were statistically significantly decreased during premating (31%), gestation (23%), and
postpartum (37%). Water intake levels in the low- and mid-dose females were similar to control
values during premating and postpartum phases but were statistically significantly increased 14%
and 10%), respectively, during gestation. Similar decreases in food consumption were noted in
female rats, with statistically significant reductions noted in the high-dose females during
premating (13%) and gestation (6%); apparent reductions in food consumption in the
2,768-mg/kg-day females during postpartum were not statistically significant due to increased
22
Isopropanol
-------
FINAL
9-16-2014
variability across all dose groups. All treated females exhibited immediate weight loss during
the premating period, with a recovery of weight gain after 1 week. Body weights and weight
gain were similar to control during the gestation period and at the beginning of the postpartum
period, but weight gain and weights in the 2,768-mg/kg-day females were statistically
significantly lower after PND 4. No statistically significant effects on male or female fertility
due to isopropanol treatment were observed in the BIBRA (1988) study, although the number of
pups/litter on PND 1 and pup survival/litter were decreased in the high-dose females (see
Table B-8). Additionally, the body weights of pups were statistically significantly decreased
(>5%) on PND 21 at >668 mg/kg-day.
No macroscopic abnormalities were observed at necropsy in females from either phase of
the present study, and no treatment-related histopathological effects were noted in reproductive
system tissues from high-dose parental animals. In the embryotoxicity study, the authors
reported that preimplantation loss was statistically significantly increased at 1,902 mg/kg-day
(1.0 ± 1.31) compared to controls (0.1 ± 0.33) (see Table B-9). Additionally, whole body edema
was observed in 40% of the fetuses in 3/8 litters in 1,902 mg/kg-day dams. Statistically
significant increases were observed in absolute kidney weight (10%) as well as relative kidney
(16%>), liver (11%>), and spleen (11%>) weights in the 1,030 mg/kg-day F0 generation males. The
high-dose F0 generation females had significantly increased absolute and relative liver weights
(19%o and 14%>, respectively) and absolute kidney (8%>) weights (see Table B-10). Statistically
significantly increased relative liver weights were observed in all dose groups for F1 generation
males and females (>10%> change compared to control values in only the high-dose male and
female pups). High-dose F1 males also had higher (not statistically significant) relative kidney
weights (5%>), and high-dose males and females had brain-weight decreases (statistically
significant for absolute weight) of less than 10%>. For the parental component of the study, a
LOAEL of 347 mg/kg-day is identified based on decreased food consumption in male F0 rats;
because 347 mg/kg-day is the lowest dose tested in male F0 rats, a parental NOAEL cannot be
determined. During the gestational component of the study, a paternal LOAEL of
1,902 mg/kg-day is identified based on decreased food consumption in F0 dams with a
corresponding NOAEL of 1,330 mg/kg-day. For F1 pups, a gestational LOAEL of
1,330 mg/kg-day is identified based on decreased body weight in both sexes on PND 4 with a
corresponding NOAEL of 668 mg/kg-day. During the postpartum component of the study, a
LOAEL of 1,053 mg/kg-day is identified based on decreased F1 pup body weight on PND 21 in
both sexes; because 1,053 mg/kg-day is the lowest dose tested in F1 pups during the postpartum
phase, a NOAEL cannot be determined.
Bevanetal. (1995)
Bevan et al. (1995) reported on a two-generation reproductive toxicity study with
isopropanol. Four groups of male and female Sprague-Dawley (S-D) rats (30 per sex),
designated as the P generation by the study authors but referred to as the F0 generation in this
document, were given isopropanol solutions in water at a volume of 5 mL/kg by gavage at doses
of 0 (control), 100, 500, or 1,000 mg/kg-day for at least 10 weeks prior to mating. Dosing was
continued in parental females during mating, gestation, and lactation through the day prior to
euthanasia (following weaning). Parental males were dosed until the day prior to euthanasia,
after delivery of their last sired litter. The date on which birth was recorded was designated as
PND 0, and offspring of the F0 generation were designated as the F1 generation. At weaning on
PND 21, two pups of each sex per litter were selected at random to become a pool of animals
from which the F1 parents would be chosen for each treatment group. The selected
23
Isopropanol
-------
FINAL
9-16-2014
F1 populations consisted of 30 neonates of each sex from the control, 100-, and 500-mg/kg-day
groups. The selected F1 population from the 1,000-mg/kg-day group consisted of only 26 pups
of each sex due to mortality encountered in that group. The F1 adult generation (designated as
P2 by the study authors) began receiving treatment on PND 21 according to the same treatment,
mating, and disposition procedures described for the F0 generation. Viability and clinical
examinations were performed, and body weight and food consumption were recorded throughout
the study. Litters were examined periodically for viability, number of offspring, and sex
determination. Gross postmortem examinations were performed on selected pups on PND 21
(5 per sex) and on all adult animals used for mating. Liver and kidney weights were recorded for
all mated adults that survived to scheduled termination. The pituitary, testes and epididymides,
prostate and seminal vesicles, vagina, uterus, and ovaries were checked for gross lesions,
prepared and stained appropriately, and then examined microscopically for all parental animals
in the control and 1,000-mg/kg-day groups; liver and kidneys from all F0 and F1 parents were
examined histopathologically.
Bevan et al. (1995) reported that a total of seven treatment-related parental deaths
occurred during the study (two F0 females and two F1 females in the 1,000-mg/kg-day group;
one F1 female in the 500-mg/kg-day group; and two F1 males in the 100-mg/kg-day group); no
other treatment-related clinical signs of toxicity were observed during the study. No details were
provided by the study authors regarding the cause(s) of the deaths. Body weights of the treated
and control F0 and F1 adult male animals were similar during the study (see Table B-l 1). When
compared to the control group, statistically significantly increased body-weight gain in the
postpartum female rats was noted in the 500-mg/kg-day dose groups (Fl, 3.1 ± 17.5 g vs.
19.2 ± 15.9 g [520%]) and 1,000-mg/kg-day dose groups (F0, 15.1 ± 30.5 g vs. 40.4 ± 24.4 g
[170%] and Fl, 3.1 ± 17.5 g vs. 25.3 ± 23.2g [720%]). No treatment-related effects on food
consumption in males or females in either parental generation were observed. Absolute and
relative liver weights of F0 males dosed with 1,000 mg/kg-day were statistically significantly
increased compared to control (10% increase in relative liver weight, see Table B-l 1). In the Fl
adult males, the absolute liver weights were increased in the 500-mg/kg-day group, and relative
liver weights were increased in the 500- and 1,000-mg/kg-day groups compared with the control
group (11% and 14%, respectively). Relative kidney weights were also increased in the adult
Fl males dosed with 1,000 mg/kg-day (7%). Absolute liver weights of the adult Fl females
were increased in the 1,000-mg/kg-day group compared with control, and relative liver weights
were increased in the F0 and adult Fl females dosed with 500 and 1,000 mg/kg-day (F0, 5% and
10%), respectively; and Fl, 8% and 18%, respectively) (see Table B-l 1). Relative kidney
weights were also increased in the F0 and adult Fl females dosed with 1,000 mg/kg-day (6% and
8%>, respectively).
Bevan et al. (1995) reported that no adverse effects of treatment were evident from gross
postmortem examinations of surviving males and females from either parental generation. The
study authors also noted that the histopathological effects in kidneys (increases in number of
hyaline droplets in the epithelial cells of the proximal convoluted tubules, incidence and severity
of epithelial degeneration and hyperplasia, incidence of proteinaceous casts in the renal tubules,
and incidence of focal interstitial mononuclear cell infiltration) in the 500- and 1,000-mg/kg-day
F0 male rats and all treated adult Fl males were likely associated with alpha 2u-globulin
nephropathy. Centrilobular hepatocyte hypertrophy was observed in one quarter of the adult
Fl male animals dosed with 1,000 mg/kg-day. No other treatment-related microscopic changes
24
Isopropanol
-------
FINAL
9-16-2014
were observed in the reproductive tissues, liver, kidneys, or other tissues. The only statistically
significant difference between treated and control groups for any reproductive parameter was a
decrease in the male mating index in the adult F1 generation at 1,000 mg/kg-day (see
Table B-12). The study authors also reported a statistically significant decrease in the live birth
index in F1 rats at 1,000 mg/kg-day. The survival index was also statistically significantly
decreased in F1 and F2 rats on PNDs 1 (at 1,000 mg/kg-day for F1 and at >500 mg/kg-day for
F2) and 4 (at >500 mg/kg-day for F1 and 1,000 mg/kg-day for F2). The survival index in F2 rats
was also statistically significantly decreased on PND 7 at >500 mg/kg-day, and the lactation
index was statistically significantly decreased in F2 rats at >500 mg/kg-day (see Table B-13).
Although there were 18 offspring deaths in the 1,000-mg/kg-day group during the postweaning
period (PNDs 21-41) prior to selection of the F2 generation (number of animals in this group
reduced to 26), the F1 and F2 offspring that survived to scheduled termination were free of
treatment-related abnormalities. Body weight was statistically significantly decreased in F1
males on PNDs 0 and 1 at 1,000 mg/kg-day, and increased on PND 21 at 100 mg/kg-day (see
Table B-14). In F1 females, body weight was statistically significantly increased on PNDs 14
and 21 at 100 mg/kg-day. In F2 males and females, body weight was statistically significantly
decreased on PNDs 0, 1, and 4 at 1,000 mg/kg-day. A parental LOAEL of 500 mg/kg-day is
identified based on increased relative liver weight in F1 adult males with a corresponding
NOAEL of 100 mg/kg-day. A reproductive LOAEL of 1,000 mg/kg-day is identified based on
decreased mating index in F1 adult males with a corresponding NOAEL of 500 mg/kg-day. A
developmental LOAEL of 500 mg/kg-day is identified based on decreased survival index in F1
and F2 offspring with a corresponding NOAEL of 100 mg/kg-day.
Carcinogenicity Studies
No studies were identified.
Inhalation Exposures
The effects of inhalation exposure of animals to isopropanol have been evaluated in three
subchronic-duration studies (Burleigh-Flaver et al.. 1998; Burleigh-Flaver et al.. 1994). one
developmental study (Nelson et al.. 1988). and two chronic-duration/carcinogenic (Burleigh-
Flaver et al.. 1997) studies. These study reports are articles published in peer-reviewed journals
or correspond to studies performed in compliance with GLP requirements. Burleigh-Flaver et al.
(1994) is a journal article containing studies performed on two different species (rat and mouse).
To differentiate between the studies, the designation of Burleigh-Flaver et al. (1994) is used for
the rat study and Burleigh-Flaver et al. (1994) is used for the mouse study. Similarly, Burleigh-
Flaver et al. (1997) is also a journal article containing studies conducted with the rat (Burleigh-
Flaver etal.. 1997) and the mouse (Burleigh-Flaver et al.. 1997).
Subchronic-duration Studies
Burleigh-Flaver et al. (1994)
The subchronic-duration study in rats by Burleigh-Flaver et al. (1994) is selected as
the principal study for the derivation of the subchronic p-RfC. Although the GLP status of
this study was not specifically stated, other research studies and reports from this author and
facility maintain GLP standards, and it is assumed that this study was conducted similarly. This
study used the F344 rat (Harlan Sprague Dawley, Inc.). Animals were housed individually in
stainless steel, wire-mesh cages throughout the study. The animals were maintained under
standard temperature and humidity conditions on a 12-hour light/dark cycle, with access to
25
Isopropanol
-------
FINAL
9-16-2014
municipal water and powdered food (certified Rodent Chow® 5002) ad libitum, except during
exposure periods and neurobehavioral evaluations. Initial body-weight ranges for the male and
female rats (8 weeks of age) were 140-165 and 112-130 g, respectively. Nominal vapor
concentrations of isopropanol of 0 (control), 100, 500, 1,500, or 5,000 ppm were used for this
study. Ten rats/sex were randomly assigned to each exposure group for the purposes of
evaluating systemic toxicity, with an additional 15 rats/sex assigned to each exposure group for
assessment of neurobehavioral function. Rats were exposed for 6 hours/day, 5 days/week, for
13 weeks, and were sacrificed the morning after their last exposure day. The animals were
exposed to air (control) or isopropanol vapor in individual cages within a stainless steel and glass
chamber (1,330 L vol) with an airflow of approximately 300 L/min. The purity of the
isopropanol prior to vaporization was determined to be 99.9% (stability not reported). The mean
(±SD) isopropanol chamber concentrations were 100 ± 5, 506 ± 12, 1,508 ± 53, and
5,008 ± 120 ppm (human equivalent concentrations [HECs] of 0, 43.9, 222, 661.8, or
2,198 mg/m3, respectively). The rats were observed daily on an individual and group basis for
clinical signs of toxicity. Direct ophthalmoscopy examinations were performed on all rats prior
to study initiation and at Week 12. Ten of the 15 rats/sex designated for neurobehavioral
function assessments were evaluated with the functional observational battery (FOB) prior to
study initiation and after Weeks 1, 2, 4, 9, and 13 (approximately 42 hours after the most recent
exposure). FOB testing was performed by trained technicians blind with respect to exposure
status and included numerous physical and neurological assessments. Motor activity evaluations
for the tested rats were done prior to initial exposure, and after 4, 9, and 13 weeks of exposure.
Body weight data were collected throughout the study period. Motor activity data were collected
for individual animals with an automated photocell-recording apparatus during 90-minute test
sessions for subsequent analysis. During Study Week 6, hematologic evaluations were done
with blood samples collected from 10 rats/sex/group, and hematologic and serum clinical
chemistry evaluations were performed on blood samples collected from 10 rats/sex/group at
study termination. All rats were anesthetized and sacrificed at the end of the study. A complete
necropsy was performed on each rat, and the brain, liver, lungs, kidneys, adrenals, testes, and
ovaries from all surviving animals were weighed. Tissues were prepared and stained as
appropriate, and an exhaustive list of tissues was examined from the control animals and animals
exposed to 2,198 mg/m3 isopropanol. Neuroanatomic pathology evaluation was conducted on
10/15 rats/sex/group used for the motor activity assessments after the brain was weighed and
measured.
Burleigh-Flaver et al. (1994) reported that no exposure-related mortality was observed in
any exposure group during the study. No clinical signs of toxicity were noted during exposures
for male and female rats in the 43.9- and 222-mg/m3 exposure groups. Ataxia, narcosis (absent
after Week 2), hypoactivity, and a lack of a startle reflex were observed in some rats after
exposure to 2,198 mg/m3, with only hypoactivity observed immediately after exposure to 661.8
mg/m3. Ataxia and/or hypoactivity also were observed in some animals in the 2,198-mg/m3
group immediately after exposure. Clinical signs observed following exposures included
swollen periocular tissue in females (at 2,198 mg/m3) and perinasal encrustation in males (at
>222 mg/m3). No exposure-related clinical signs were observed after exposure to 43.9 mg/m3.
Isopropanol exposure did not affect any of the FOB parameters. Statistically significantly
increased motor activity was observed in the females in the 2,198-mg/m3 exposure group after
Weeks 9 (57% increase) and 13 (26% increase), with no changes noted in the males. Body
weight and/or body-weight gain were statistically significantly lower after Week 1 for all rats in
26
Isopropanol
-------
FINAL
9-16-2014
the 2,198-mg/m3 group and the females in the 661.8-mg/m3 group (tabular, numerical data not
reported). However, decreases in body weight and/or body-weight gain were not present after
Week 2. In general, these parameters were significantly increased by Week 5 and after in the
661.8- and 2,198-mg/m3 exposure groups (end of study percentage increases in body-weight gain
were 12 and 16% at 2,198 mg/m3, and 7 and 8% at 661.8 mg/m3, in the males and female,
respectively). An initial significant decrease in food consumption in the females in the
2,198-mg/m3 exposure group reversed after Week 1 (tabular, numerical data and significance
level were not reported), and significant increases in food consumption were observed in the
2,198-mg/m3 group by Weeks 4-5. Percentage increases in food consumption at the end of the
study in the 2,198-mg/m3 groups were 5 and 13%, in the males and females, respectively.
Increased water intake was observed beginning at Week 2 in the 661.8- and 2,198-mg/m3 groups.
Changes in hematologic parameters generally observed at 2,198 mg/m3 in male and female rats
were suggestive of a slight, but transient, anemia (present at Week 6 but resolved by Week 14);
no exposure-related changes in serum clinical chemistry parameters occurred in the rats at
Week 14. Relative (to body) liver weight was increased at 2,198 mg/m3 (8 and 5% in male and
female rats, respectively). The only exposure-related change observed following histological
examination was the presence of increased number and size of hyaline droplets within the
kidneys in the exposed male rats (not clearly concentration-dependent). Initial decreases in body
weight and food consumption, and the presence of anemia, were transient and minor. A LOAEL
of 2,198 mg/m3 is identified for increased motor activity in female rats with a corresponding
NOAEL of 661.8 mg/m3.
Burleigh-Flayer et al. (1998)
Burleigh-Flaver et al. (1998) reported a subchronic inhalation toxicity follow-up study
with isopropanol conducted according to U.S. TSCA GLP standards (BushyRun. 1994). The
BushyRun (1994) report is a subchronic-duration, 13-week study submitted to the EPA and later
published as part of Burleigh-Flayer et al. (1998). Female F344 rats were assigned randomly to
the control or exposure groups (30/group) and exposed to target concentrations of 0 (control) or
5,000 ppm of isopropanol vapor for 6 hours/day, 5 days/week. The actual concentration of
isopropanol vapor for the exposed group was 5,011 (±105) ppm (HEC = 2,199 mg/m3). Fifteen
rats in each group were exposed to isopropanol for 9 weeks, and the other 15 were exposed for
13 weeks. Motor activity was evaluated during the exposure periods, as well as for 1 week after
the end of exposure for the 9-week subgroup and for 6 weeks after the end of exposure for the
13-week subgroup to assess the potential for reversibility. Observations for clinical signs of
toxicity, including ataxia and hypoactivity, were made on an individual and group basis. Motor
activity evaluations were done prior to initial exposure, and after 4, 7, and 9 weeks of exposure
(9-week subgroup) and 4, 7, 9, 11, and 13 weeks of exposure (13-week subgroup). Reversibility
of potential effects was evaluated at 2, 4, and 7 days after the final exposure in the 9-week
subgroup and at 2, 4, 7, 14, 21, 28, 35, and 42 days after final exposure in the 13-week subgroup.
Motor activity measurements were conducted in an isolated room under controlled conditions
(sound and light level, and odor). Weight data were collected throughout the study. Data for
ambulatory activity, fine motor activity, rearing activity, and the sum of these individual types of
activity were collected for individual animals with an automated photocell-recording apparatus
in nine consecutive 10-minute intervals (90-minute test session) for subsequent analysis.
Statistical significance was assessed but significance levels are not reported for any parameter.
The animals were sacrificed by carbon dioxide overdose after the final motor activity evaluation;
necropsies were not performed.
27
Isopropanol
-------
FINAL
9-16-2014
Burleigh-Flaver et al. (1998) reported that no exposure-related mortality was observed
during the study, and clinical signs during exposure were minimal (i.e., apparent decreased
movement within the enclosures and diminished startle response). Swollen periocular tissue was
observed during the nonexposure periods. Although body weight and body-weight gain were
decreased for the exposed rats after the first week of exposure, statistically significant increases
in these parameters were observed for exposed rats by Week 3. Significant increases in body
weight continued to be observed for isopropanol-exposed rats throughout the remainder of the
study (mean body weight and body-weight gain for the 9-week subgroup rats were increased by
6% and 17%, respectively, relative to control; for the 13-week subgroup rats, these increases
were 5% and 13%, respectively, relative to control). Weight increases were maintained for
isopropanol-exposed rats during the recovery period, with mean body weight and body-weight
gain for the 13-week subgroup rats increased by 3% and 9%, respectively, after Week 19.
Increases in mean cumulative motor activity (the sum of total activity across a 90-minute test
session) were observed at all of the evaluation time points during each exposure regimen and
Postexposure Day 1 (4, 7, and 9 weeks, and 4, 7, 9, 11, and 13 weeks, respectively) (see
Table B-15). In the 9-week exposure group, cumulative test session activity was not different
from control values by Postexposure Day 2. In contrast, cumulative test session activity
remained increased compared to control values through Postexposure Day 7 in the 14-week
exposure group, was not significantly different from control on Postexposure Days 14 and 21,
and then showed a statistically significant increase on Postexposure Day 28. Repeated measures
analysis of motor activity habituation curves indicated significant differences between the
isopropanol exposure and control groups during some study weeks (Week 7 for the 9-week
exposure group, and Weeks 4, 9, and 11 for the 13-week group). Additionally, some significant
differences were noted in postexposure habituation curves. A LOAEL of 2,199 mg/m3 is
identified from this study for increased motor activity in female rats. Because 2,199 mg/m3 is
the only concentration tested, a NOAEL cannot be determined.
Burleigh-Flayer et al. (1994)
In another sub chronic-duration inhalation study, Burleigh-Flayer et al. (1994) exposed
CD-I mice to isopropanol vapor for up to 13 weeks. Animal husbandry and target vapor
concentrations were as described previously Burleigh-Flayer et al. (1994). Ten animals/sex were
randomly assigned to each exposure group, with exposure parameters and system as described
previously. A complete necropsy was performed on each animal. The mean (±SD) isopropanol
concentrations were 100 ± 5, 506 ± 12, 1,508 ± 53, or 5,008 ± 120 ppm (HECs of 0, 43.9, 222,
661.8, and 2,198 mg/m3).
Burleigh-Flayer et al. (1994) reported that no exposure-related mortality was observed in
any exposure group during the study. No clinical signs were noted during exposures for mice in
the 43.9- and 222-mg/m3 groups. During exposure, ataxia, narcosis, and hypoactivity were
observed in the 661.8- and 2,198-mg/m3 groups, and lack of a startle reflex was noted at
2,198 mg/m3. Ataxia and/or hypoactivity also were observed in some animals in the
2,198-mg/m3 group immediately after exposure. Significantly increased body weight and
body-weight gain were observed in the females in the 2,198-mg/m3 group by Week 3 (end of
study percentage increases in body weight and body-weight gain were 13 and 71%, respectively;
no significance level reported), with no exposure-related effects on weight noted in the males.
There were no exposure-related effects on food consumption in any group. Increased water
intake was observed in the males in the 661.8- and 2,198-mg/m3 groups (during Weeks 1 and 2),
28
Isopropanol
-------
FINAL
9-16-2014
and in the females (2,198-mg/m3 group) throughout the study. Although there were no
exposure-related changes in hematologic or serum clinical chemistry parameters for the males
(2,198 mg/m3) at Week 14, the study authors suggested that changes in these parameters (present
in the females in this exposure group) were indicative of slight dehydration. Relative (to body)
liver weight was increased in the females in the 661.8- and 2,198-mg/m3 groups (>10% change
compared to control values at both concentrations). No exposure-related changes were observed
following histological examination in the exposed mice. A LOAEL of 661.8 mg/m3 is identified
for increased relative liver weight) in female mice with a corresponding NOAEL of 222 mg/m3.
Developmental Studies
Nelson et al. (1988)
Nelson et al. (1988) reported a developmental inhalation toxicity study in the S-D rat
with isopropanol; a subsequent peer-reviewed published journal article by Nelson et al. (1990)
included summarized data from this study as well as similar investigations with 12 other
alcohols. Females were placed individually with breeder males for mating. Pregnant animals
(n = 15, 14, 13, and 9) were assigned to 0, 3,500, 7,000, or 10,000 ppm exposure groups.
Measured isopropanol vapor exposures throughout the study (Nelson et al.. 1988) were similar to
target concentrations (generally within 10%, HECs of 0, 2,516, 5,048, and 7,185 mg/m3).
Maternal weight data were collected throughout the study periods, and food consumption and
water intake were determined weekly. Pregnant females were exposed to isopropanol vapors on
GDs 1-19 for 7 hours per day in 0.5-m3 Hinner-type exposure chambers; control animals were
exposed to filtered air. Females were weighed and sacrificed by CO2 asphyxiation on GD 20.
Uteri with ovaries were removed and examined for corpora lutea, resorptions, and live fetuses.
Half of the fetuses underwent visceral examination, and the remaining fetuses were examined for
skeletal defects. Additionally, nonpregnant adult female rats were exposed to isopropanol vapors
for 1, 10, or 19 days (exposure conditions identical to pregnant animals). A separate group of
young females (n = 8, approximately 90 g) were exposed to the high concentration of
isopropanol (7,185 mg/m3) for a single 7-hour period to assess toxicity in younger animals.
Blood was collected after CO2 overdose at the end of each exposure period (1, 10, or 19 days),
and isopropanol concentrations were determined by an appropriate gas chromatographic method.
Dams exposed to 7,185 and 5,048 mg/m3 exhibited narcosis and unsteady gait, early in
the exposure protocol, but these signs diminished in both groups after 19 days of exposure; no
effects were observed in the 2,516-mg/m3 exposure group. Isopropanol concentrations in blood
tended to decrease over time (Days 1-19), and isopropanol concentrations in the younger
females were higher than in the nonpregnant adults. Animals receiving 7,185- and 5,048-mg/m3
isopropanol vapor showed reductions in food consumption during the first 2 weeks of exposure,
and decreased weight gain across the 19-day exposure period; these effects were not statistically
significant. Six of the 15 females at the highest concentration were not pregnant, which the
study authors suggested as a failure of implantation. In addition, dams in the high-concentration
group had statistically significant decreases in mean number of implants per dam and implants
alive per litter (embryotoxicity), with a concomitant statistically significant increase in the
number of resorptions per litter (see Table B-16). Concentration-dependent, statistically
significant reductions in fetal body weight occurred after maternal exposure in all groups; this
effect only reached a 5% or greater reduction level at >5,048 mg/m3. The number of skeletal
malformations was statistically significantly increased in the two highest concentration groups
(5,048 and 7,185 mg/m3), primarily attributed to rudimentary cervical ribs; no other
malformation rates were affected. The study authors noted that teratogenic effects at these two
29
Isopropanol
-------
FINAL
9-16-2014
concentrations may have been secondary to maternal toxicity. A maternal NOAEL of
7,185 mg/m3 is identified based on the lack of significant effects observed. No maternal LOAEL
can be determined. A developmental LOAEL of 5,048 mg/m3 is identified based on decreased
fetal body weight (>5% change compared to control values) and increased skeletal
malformations in males and females with a corresponding NOAEL of 2,516 mg/m3.
Reproductive Studies
No studies were identified.
Carcinogenicity/Chronic-duration Studies
Burleigh-Flayer et al. (1997)
The study conducted by Burleigh-Flayer et al. (1997) is selected as the principal
study for deriving the chronic p-RfC. This chronic-duration inhalation carcinogenicity study
was conducted according to GLP standards and submitted previously to the EPA as BushyRun
(1994). This study was conducted with F344 rats (Harlan Sprague Dawley, Inc.). The animals
were housed two per cage for 2 weeks, then individually for the remainder of the study in
stainless steel, wire-mesh cages. The animals were maintained under standard temperature and
humidity conditions on a 12-hour light/dark cycle, with access to municipal water and pelleted
food (Agway Prolab Animal Diet 3000) ad libitum, except during exposure periods. Initial
body-weight ranges for males and females (7 weeks of age) were 121-165 and 93-124 g,
respectively. Target isopropanol vapor concentrations were 0 (control); 500, 2,500, or
5,000 ppm. Actual isopropanol concentrations were determined to be within 2% of nominal
(HECs of 0, 221, 1,101, or 2,211 mg/m3). Seventy-five animals/sex were randomly assigned to
each exposure group. A core group (65/sex/group) was exposed for 6 hours/day, 5 days/week,
for at least 104 weeks, with an additional 10 animals/sex/group designated for interim sacrifice at
72 weeks. Animals were exposed to either air (control) or isopropanol vapor in stainless steel
and glass chambers (4,320 L vol) with an airflow of approximately 900 L/min. The purity of the
isopropanol prior to vaporization was determined to be 99.9%, and purity/stability was evaluated
at 6-month intervals. Observations were made daily for individual clinical signs of toxicity, with
group observations made during exposures. Indirect ophthalmoscopic examinations were made
initially and at 17 months, 19 months, and at terminal sacrifice. All animals were weighed
initially, weekly through Week 14, and then every other week. Blood smears were obtained
from core animals at approximately 13 and 19 months, with differential leukocyte count
evaluations for all control and high-concentration animals. Full hematologic evaluations were
performed on blood samples collected at terminal sacrifice. Urinalysis, urine chemistries, and
osmolality determinations were performed at selected time points (Weeks 57 and 58, Week 74,
and terminal sacrifice). Animals were euthanized at the interim and terminal time points, and the
brain, liver, lungs, kidneys, heart, spleen, and testes from all surviving animals were weighed. A
complete necropsy was performed on each animal; tissues were prepared and stained as
appropriate, and numerous tissues were evaluated in the control and high-concentration animals.
In the low and intermediate concentration-groups, only the kidneys, testes, and gross lesions
were microscopically evaluated. Continuous, parametric data were compared with Levene's test
for homogeneity of variance, by ANOVA, and by ^-tests. Incidence data were compared with
Fisher's Exact test. Nonparametric data were evaluated with the Kruskal-Wallis test, and the
Wilcoxon rank sum test as modified by Mann-Whitney.
30
Isopropanol
-------
FINAL
9-16-2014
Burleigh-Flaver et al. (1997) reported that 100% mortality occurred for males at
2,211 mg/m3, with a significantly decreased mean survival time noted for males in this group
(577 days) compared to controls (631 days). No differences in mean survival time were noted
for the females. Transient clinical signs noted at 1,101 and 2,211 mg/m3 during exposure
included hypoactivity, lack of a startle reflex, ataxia, prostration, and narcosis, with no clinical
signs observed at 221 mg/m3 during or after exposure. Clinical signs noted during nonexposure
periods included emaciation and dehydration in the 2,211 -mg/m3 males, urine stains in both
sexes at >1,101 mg/m3 and swollen periocular tissue in the 2,211-mg/m3 females. There was no
notable increase in the incidence of eye lesions. Decreased mean body weight and/or
body-weight gain was observed initially at 2,211 mg/m3 (through Week 2 of exposure). From
this point, body weight increased, and increased body weight and body-weight gain were noted
by the end of Week 6. At Week 52, body weight and body-weight gain were increased 5 and
7%, respectively (2,211-mg/m3 males), and 4 and 6%, respectively (1,101-mg/m3 males).
Concentration-related increases in body weight and body-weight gain were observed in the
female rats after Week 5. At Week 52, body weight and body-weight gain were increased 6 and
10%, respectively, in 2,211-mg/m3 females and 4 and 7%, respectively, in 1,101-mg/m3 females,
with a slight (1% or less) increase in the 221-mg/m3 female rats. No exposure-related changes in
hematologic parameters were observed in the rats in this study. Statistically significant changes
were generally observed in urinalysis and urine chemistry parameters in the 2,211-mg/m3 rats
(see Table B-17). Osmolality was decreased in males at 13 months, decreased in males and
females at 17 months, and decreased in females at 24 months. Total protein was increased in
males at 13 months, and increased in males and females at 17 months. Total volume was
increased in females at 13 months, increased in males and females at 17 months, and increased in
females at 24 months. Glucose was decreased in females at 13 months, decreased in males at
17 months, and decreased in females at 24 months.
Burl eigh-Fl aver et al. (1997) reported increased liver weight (2,211-mg/m3 males) and a
concentration-related increase in testes weight at the interim sacrifice (Week 73) but not in the
terminal experimental group (see Table B-18). No effects were noted in kidney or brain weights
in male or female rats at Week 73. Organ-weight changes in rats at Week 104 included
decreased kidney weight (221- and 1,101-mg/m3 females), increased liver weight (1,101-mg/m3
males and 2,211-mg/m3 females), and decreased brain weight (all exposed females).
Microscopic evaluation of male rats at the interim sacrifice indicated increased atrophy of
seminiferous tubules and increased severity of renal lesions. At the interim and terminal
sacrifice of rats at >1,101 mg/m3, increased severity of renal lesions in all rats (including those
found dead or moribund) and the incidence of these lesions were observed, with incidence and
severity greater in males compared to females (see Tables B-19 and B-20). Rats found dead or
moribund displayed increased organ mineralization, and a variety of other nonneoplastic lesions.
No increased frequencies of neoplastic lesions were observed in the females. In the males,
concentration-dependent increases in testicular interstitial (Leydig) cell adenomas were seen in
all exposure groups among the animals euthanized or found dead (57.7-94.7%) exposed vs.
64.9%o in concurrent controls) and when considering all animals (77.3-94.7%) exposed vs. 64.9%>
concurrent controls). The study authors concluded that although the incidence was substantially
increased in a concentration-dependent manner, the controls in this study were lower than
historical controls. Furthermore, this tumor has been identified as the most frequently observed
spontaneous tumor in the male F344 rat (Haseman et al.. 1990; Takaki et al.. 1989). A review of
the incidence of Leydig cell adenomas in male F344 controls from 2-year NTP studies reported a
31
Isopropanol
-------
FINAL
9-16-2014
mean incidence of 88% in control (unexposed) males. Additionally, Leydig cell adenoma
incidences of 86 and 91% were reported in male F344 control rats from two studies conducted
previously at the facility used in the Burleigh-Flaver et al. (1997) study, similar to the range of
incidence for this tumor in the exposed males in this study (77.3-94.7%). Therefore, the study
authors suggested that this increase was a study artifact. Furthermore, due to the common
occurrence of these tumors in male rats, the biological significance of an increased incidence of
Leydig cell adenomas in male F344 rats is unclear. Chronic renal disease was identified as the
main cause of death in female rats in the 2,211-mg/m3 group and male rats in the 1,101-mg/m3
group, as well as for early mortality in males in the 2,211-mg/m3 group. A LOAEL of
1,101 mg/m3 is identified based on increased relative liver weight in male rats with a
corresponding NOAEL of 221 mg/m3.
Burleigh-Flaver et al. (1997)
Burleigh-Flaver et al. (1997) also conducted a chronic-duration inhalation carcinogenicity
study in the CD-I mouse (Charles River Breeding Laboratories, Inc.). These data were also
reported in a non-peer-reviewed technical report by the BushyRun (1994). Initial weight ranges
for the male and female mice (7 weeks of age) were 22-35 and 19-28 g, respectively. Animal
husbandry conditions were as described previously for the rat study (Burleigh-Flaver et al..
1997). Target isopropanol vapor concentrations were 0 (control); 500, 2,500, or 5,000 ppm and
the actual concentrations were within 2% of nominal (HECs of 0, 221, 1,101, or 2,211 mg/m3).
Seventy-five mice/sex were randomly assigned to each exposure group, with a core group
(55/sex/group) exposed for 6 hours/day, 5 days/week, for at least 78 weeks, and an additional
10 mice/sex/group were designated for an interim sacrifice at 54 weeks. The remaining
10 mice/sex/group were assigned to a recovery group, exposed for 54 weeks, but sacrificed at
Week 78. Isopropanol vapor exposure was conducted as described previously. Observations
were made daily for individual clinical signs of toxicity, with group observations made during
exposures. All mice were weighed initially, weekly through Week 14, and then every other
week. Blood smears were obtained from the core group of animals at approximately 12 months,
with differential leukocyte count evaluations for all control and high concentration group
animals, and full hematologic evaluations were performed on blood samples collected at terminal
sacrifice. Animals were sacrificed at the interim and terminal time points, with organ and tissue
treatments as described previously. Kidneys, liver, testes, and gross lesions from animals in the
low and intermediate groups also were evaluated. Statistical analyses were conducted as
described previously.
Burleigh-Flaver et al. (1997) reported that there were no differences in mean survival
time for the interim, core, or recovery groups. Transient clinical signs noted at >1,101 mg/m3
during exposure included hypoactivity, lack of a startle reflex, ataxia, prostration (2,211 mg/m3
only), and narcosis, with no clinical signs observed at 221 mg/m3 during or after exposure.
Ataxia also was noted at 2,211 mg/m3 immediately following exposure, but this effect was
absent the following morning. Concentration-related increases in mean body weight and
body-weight gain were observed in the core group of mice throughout the study as follows: 2 and
6%, respectively (221-mg/m3 males), 5 and 23%, respectively (1,101-mg/m3 males), 7 and 30%,
respectively (2,211-mg/m3 males), and 5 and 30%, respectively (2,211-mg/m3 females). A
15% increase in body-weight gain only was observed in 1,101-mg/m3 females. Additionally, in
the recovery group, increases were observed in mean body weight and body-weight gain in the
2,211 mg/m3 male mice (6 and 30%, respectively) and in body-weight gain only in the
32
Isopropanol
-------
FINAL
9-16-2014
1,101-mg/m3 males (20%) and >l,101-mg/m3 females (approximately 10-20%). No
exposure-related changes in hematologic parameters were observed in the mice in this study.
Statistically significant relative (to body) organ-weight changes in the interim group
(Week 54 termination) were limited to increased liver and decreased brain weights in the
2,211-mg/m3 males and females and concentration-related increases in liver weight in males in
the recovery group (where there were no exposure-related effects on brain weight) (see
Table B-21). Statistically significant effects noted in the core group at terminal sacrifice
(Week 78) included increased liver weight in the 2,211-mg/m3 females, decreased brain weight
in the 2,211-mg/m3 males and females, and a decrease in testes weight in males in all
concentration groups. In the recovery group, liver weight in males was statistically significantly
and concentration-dependently increased by 10—30% in all exposed groups. There were also
changes in absolute organ weights in the different exposure duration groups (see Table B-22).
Absolute liver weight in males and females was statistically significantly increased at
2,211 mg/m3 at the interim sacrifice. The following changes were observed at the terminal
sacrifice: absolute liver weight in males was statistically significantly increased at >1,101 mg/m3
and absolute testes weight was statistically significantly decreased at 221 mg/m3; absolute brain
weight was statistically significantly decreased in females at 2,211 mg/m3. In the recovery
group, absolute liver weight was statistically significantly increased in males at >1,101 mg/m3.
Microscopic evaluation revealed statistically significant, seminal vesicle ectasia (2,211-mg/m3
males), tubular proteinosis/dilation (221-mg/m3 males and females, 1,101-mg/m3 males, and
2,211-mg/m3 females), increased adrenal congestion, mucosal cell hyperplasia in the stomach,
and extramedullary hematopoiesis and hemosiderosis in the spleen (2,211-mg/m3 females) (see
Table B-23). However, none of these effects were determined to be concentration-related. No
increased frequencies of neoplastic lesions were observed in any animals. A LOAEL of
221 mg/m3 is identified for decreased absolute and relative testes weights in male mice. Because
221 mg/m3 is the lowest exposure tested, a NOAEL cannot be determined.
33
Isopropanol
-------
FINAL
9-16-2014
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS)
Table 4A contains summary data from genotoxicity studies with isopropanol, and Table 4B contains summary data from other types of
studies with isopropanol (e.g., pharmaco/toxicokinetics, acute human exposure, occupational). Brief study summaries are included after the
tables.
Table 4A. Summary of Isopropanol (CASRN 67-63-0) Genotoxicity and Mutagenicity Studies
Endpoint
Test System
Dose
Concentration3
Resultsb
Comments
References
Without
Activation
With
Activation
Genotoxicity studies in prokaryotic organisms
Reverse mutation
Salmonella typhimurium,
TA98, 100, 1535, 1537, 1538
2,500 (ig/mL
-
-
NA
IARC (1999); Zeiser et
al. (1992)
Reverse mutation
S. typhimurium, TA97, 98,
100, 1535, 1537
5,000 (ig/mL
—
—
NA
IARC (1999): Zeiser et
al. (1992)
Reverse mutation
Escherichia coli WP2 uvrA
2,500 (ig/mL
-
-
NA
IARC (1999)
SOS repair induction
ND
Genotoxicity studies in nonmammalian eukaryotic organisms
Mutation
ND
Recombination induction
ND
Chromosomal abberation
ND
Meiotic nondisjunction, aneuploidy
Neurospora crassa
NR
-
-
NA
IARC (1999)
Mitotic arrest
ND
Genotoxicity studies in mammalian cells—in vitro
Mutation
Chinese hamster ovary (CHO)
cells, hrpt locus
5,000 (ig/mL
-
-
NA
IARC (1999)
Chromosomal aberrations
ND
Sister chromatid exchange (SCE)
Chinese hamster V79 cells
6,000 (ig/mL
-
-
NA
IARC (1999)
DNA damage
ND
34
Isopropanol
-------
FINAL
9-16-2014
Table 4A. Summary of Isopropanol (CASRN 67-63-0) Genotoxicity and Mutagenicity Studies
Endpoint
Test System
Dose
Concentration3
Resultsb
Comments
References
Without
Activation
With
Activation
DNA adducts
ND
Genotoxicity studies in mammals—in vivo
Chromosomal aberrations
ICR mouse bone marrow cells
2,500 (ig/mL ip x 1
-
ND
NA
I ARC (1999)
Sister chromatid exchange (SCE)
ND
DNA damage
ND
DNA adducts
ND
Mouse biochemical or visible specific
locus test
ND
Dominant lethal
ND
Genotoxicity studies in subcellular systems
DNA binding
ND
aLowest effective dose for positive results, highest dose tested for negative results.
b+ = positive; ± = equivocal or weakly positive; - = negative; T = cytotoxicity; DU = data unsuitable; NA = not applicable; NV = not available; ND = no data; NDr = not
determined; NI = not identified; NP = not provided; NR = not reported; NR/Dr = not reported but determined from data; NS = not selected.
35
Isopropanol
-------
FINAL
9-16-2014
Table 4B. Summary of Other Isopropanol (CASRN 67-63-0) Studies
Test
Materials and Methods
Results
Conclusions
References
Dermal Absorption and
Pharmacokinetics
Isopropanol (70% w/w) aqueous solution
was applied to the shaved backs of male
and female F344 rats for 4 h. Absorption,
elimination, and total recovery of
14C-isopropanol after dermal (4 h and
5 min) and intravenous (iv) administration
to rats were determined. Dermal absorption
rates and permeability coefficients were
calculated.
Maximum isopropanol blood concentrations
were achieved at 4 h (exposure limit) and
decreased to below quantifiable limit (BQL)
by 8 h. Acetone blood levels increased and
peaked at 4.5 h (male) and 5 h (female) and
were BQL by 24 h. After iv administration,
approximately 50-55% of the dose was
eliminated as CO2, with an additional
20-26% eliminated as expired volatiles and
5-6% eliminated in the urine.
Calculated dermal
absorption rates were
approximately
0.8 mg/cm2/h, and
calculated permeability
coefficients suggested
rapid dermal absorption.
Eastman Kodak
(1995)
Dermal Toxicity
Study in rabbits; best available copy is not
legible.
None
None
OTS (1987)
Pharmacokinetics
A physiologically based pharmacokinetic
(PBPK) model for isopropanol and its
major metabolite, acetone, is described.
The subseauent reoorts (Gentry et al.. 2003;
Gentry et al.. 2002) utilized this PBPK
model to derive putative toxicity values for
acetone and isopropanol.
The robustness and validity of the model
were demonstrated by its ability to fit
existing exposure data (various species and
routes of administration). Putative toxicity
values were generated for acetone and
isopropanol with existing peer-reviewed
data and compared to toxicity values
derived with EPA default methodologies.
The authors reported that
this model provided a
validated framework for
chemical-specific route-
to-route extrapolation and
cross-species dosimetry
that could potentially be
used in support of
isopropanol and acetone
risk assessment.
Clewell et al. (2001);
Gentry et al. (2002);
Gentry et al. (2003)
Metabolism
The potentiation of carbon tetrachloride
(CCI4) hepatotoxicity was investigated in
fresh microsomes isolated after oral
administration of isopropanol or acetone in
the male S-D rat.
Isopropanol and acetone administration at
16 or 24 h prior to microsome isolation
increased covalent binding of 14CCl4 and
\-dcmcthvlation of dime thy lnitrosamine
but did not increase CYP450 or
cytochrome c reductase content in the
microsomes. In vitro addition of
isopropanol and acetone to microsomes was
inhibitory.
Due to the lack of
CYP450 or cytochrome c
reductase content effects,
the mechanism for
increased covalent binding
of l4CCli and Y-
demethylation of
dimethylnitrosamine by
isopropanol and acetone
was not determined.
Sines et al. (1973)
36
Isopropanol
-------
FINAL
9-16-2014
Table 4B. Summary of Other Isopropanol (CASRN 67-63-0) Studies
Test
Materials and Methods
Results
Conclusions
References
Immunotoxicity
The immunosuppressive potential of
isopropanol was investigated in vitro in
human T lymphocytes and NK cells (up to
1.2% w/v) by various methods (CFSE
staining, Western blot and luciferase assay,
cytokine analysis, ELISA-based
transcription factor activation assay, and
cytotoxicity assays) and in vivo (2 g/kg i.p.
to generate a blood alcohol concentration of
200 mg/dL [0.2% or 33 mM] after 30 min)
with sepsis-induced female BALB/c mice.
Treatment was detrimental to human
T lymphocyte and NK cell activity (at IPA
concentrations as low as 0.08% [13 mM] as
measured by IFN-release in NK cells and
0.16% [26 mM] as measured by IL-2 and
IFN-release in T cells) and reduced the
ability to release IL-2 and IFN-gamma in
the serum in response to staphylococcal
enterotoxinB (SEB), in vivo. Animals
injected with SEB after presensitization
with D-galactosamine developed a
fulminating toxic shock syndrome with a
median survival of 9 h. The syndrome did
not occur or had its development delayed in
all mice treated with isopropanol, and the
majority of mice survived.
The data suggest that
acute isopropanol
exposure reduces the
ability of lymphocytes to
produce proinflammatory
cytokines and may
compromise the immune
system. These results may
be relevant in the context
of acute intoxication
considering a significant
effect in vitro with
isopropanol
concentrations as low as
0.08-0.16% (13-26 mM)
was observed, and the
potential for skin
application at higher
concentrations (even in a
hypothetical situation
assuming poor dermal
absorption).
Desv et al. (2008)
Occupational
Retrospective analysis of 434 workers
involved in isopropanol manufacture by the
decreased sulfuric acid method. Exact
exposure routes and/or exposure levels
were not determined (length of service
ranged from 6 mo to 17 yr). Cancer deaths
in the cohort were compared to expected
cancer deaths.
A slight excess in all cancer deaths (9 vs.
7.28) and in respiratory cancer (4 vs. 2.96)
for workers exposed to isopropanol during
manufacture after 20+ yr was observed.
Approximately one third of the workers in
the isopropanol cohort also were involved
in the manufacture of epichlorhydrin, which
is a confounding factor.
No clear evidence that
exposure during
isopropanol manufacture
at this site caused or
increased the risk of
cancer.
Shell Oil Co (2000)
37
Isopropanol
-------
FINAL
9-16-2014
Table 4B. Summary of Other Isopropanol (CASRN 67-63-0) Studies
Test
Materials and Methods
Results
Conclusions
References
Occupational
Retrospective analysis of 335 workers
involved in ethanol and isopropanol
manufacture, and a second cohort with an
additional 408 employees (n = 743 total).
Cancer deaths in the cohort were compared
to expected cancer deaths.
The incidence of laryngeal cancer was
5-fold higher than expected. Other
disproportionate cancer values were
excluded due to low case numbers (n = 1).
The increased incidence of
laryngeal cancer is
associated with the high
acid ethanol process
(exposure to diethyl
sulfate) and not associated
with the low acid
isopropanol process.
Lvnchetal. (1979)
Acute Human Exposure
Five male and 7 female adult subjects,
occupationally-exposed and control groups,
vapor inhalation, 0 or 164 mg/m3, 4 h.
Subjects rated symptoms during exposure
with respect to odor intensity, sensory
irritation, and annoyance. Objective
endpoints obtained before, during, and after
exposure included ocular hyperemia, nasal
congestion and secretion, and respiration.
Isopropanol exposure was compared to
phenylethyl alcohol (negative control) and
clean air.
Higher intensity ratings for odor, irritation,
and annoyance were noted by
occupationally-exposed subjects, but
overall sensory irritation was rated low.
Respiration frequency was increased during
exposure to isopropanol in both groups.
Increased respiration
frequency may be a result
of a voluntary change in
breathing due to odor
instead of a reflexive
change due to a sensory
irritant.
Smeets et al. (2002)
Acute Human Exposure
Twenty-eight male and28 female adults,
vapor inhalation, 0 and 31 mg/m3, 2 h (at
rest). Subjects rated symptoms on a visual
analog scale before, during, and after
exposure, and blinking frequency was
measured during exposure. Pulmonary
function, nasal swelling, inflammatory
markers in nasal lavage, and color vision
were measured before, and at 0 and 3 h
after exposure.
Discomfort in throat and airways as well as
fatigue were reported, with no significant
effects on pulmonary function due to
isopropanol exposure.
Women were reported to
be slightly more sensitive
than men to the acute
irritant effects of
isopropanol.
Ernsteard et al.
(2002)
38
Isopropanol
-------
FINAL
9-16-2014
Table 4B. Summary of Other Isopropanol (CASRN 67-63-0) Studies
Test
Materials and Methods
Results
Conclusions
References
Acute Human
Exposure/Toxicokinetics
Eight male and 9 female subjects, human
adult, vapor inhalation, 0 and 350 mg/m3,
2 h (during light physical exercise),.
Isopropanol and acetone were monitored up
to 24 h after exposure in exhaled air, blood,
saliva, and urine, and the toxicokinetic
profile in blood was determined.
Genotypes were determined by PCR-based
assays for ADH and CYP2E1. The
CYP2E1 phenotype was assessed by the in
vivo 2 h plasma
6-hydroxychlorzoxazone/chlorzoxazone
metabolic ratio.
Sex differences were observed, and females
exhibited lower respiratory uptake, smaller
volume of distribution, shorter half-life of
isopropanol in blood, and a higher apparent
total clearance when corrected for body
composition. Isopropanol levels in exhaled
air at 10 min postexposure and later were
increased approximately 4-fold, and acetone
in blood was slightly higher in women.
Marked sex differences included an
approximately 100-fold increase in salivary
acetone in women (no increase in men)and
a 10-fold higher blood:breath ratio in men,
suggestive of sex differences in isopropanol
lung metabolism. There was no significant
difference in toxicokinetics between
subjects of different metabolic genotypes or
phenotypes.
Although most of the sex
differences are consistent
with anatomical
differences between men
and women, body build
does not explain the
differences in isopropanol
levels in expired air and
acetone in saliva.
Ernsteard et al.
(2003s)
39
Isopropanol
-------
FINAL
9-16-2014
Genotoxicity and/or Mutagenicity Studies
Several published, peer-reviewed journal articles have examined the genotoxic potential
of isopropanol in a variety of test systems including reverse mutation in S. typhimurium TA100,
TA1535, TA1537, TA1538, TA98, and E. coli WP2 uvrA (IARC. 1999). reverse mutation in
S. typhimurium TA100, TA1535, TA1537, TA98, and TA97 (Zeiger et al.. 1992). meiotic
nondisjunction and aneuploidy in N. crassa (IARC. 1999). gene mutation in Chinese hamster
ovary (CHO) cells, hprt locus in vitro and micronucleus test in ICR mouse bone marrow cells in
vivo (IARC. 1999). and sister chromatid exchange in Chinese hamster V79 cells in vitro (IARC.
1999). The results of all tests (with or without an exogenous metabolic system) were negative,
and isopropanol was not genotoxic under these test systems and conditions.
Dermal Absorption, Metabolism, and Pharmacokinetic Studies
A study examining the dermal absorption and pharmacokinetics of isopropanol was
conducted according to EPA and TSCA GLP standards by the Eastman Kodak Company and
submitted to the EPA (Eastman Kodak. 1995). Isopropanol (greater than 99% purity) was
prepared as a 70% (w/w) aqueous solution (0.3 mL) and applied under occlusion to the shaved
backs of male and female Fischer 344 rats for a 4-hour period. Mass balance determinations
were also conducted after dermal and intravenous (iv) administration of 14C-isopropanol (purity
not reported). Dermal exposures (4 hours and 5 minutes) were performed similar to
administration of the nonradiolabeled material, and iv administration of 14C-isopropanol in
isotonic saline at a concentration of 24 mg/g (6 mg/rat) was given as a bolus injection in a lateral
tail vein (0.25 mL).
Maximal blood concentrations of isopropanol (approximately 0.2 |imol/g) were achieved
by 4 hours in the dermal study (Eastman Kodak. 1995); concentrations declined after 4 hours
(removal of material) and were below quantifiable limits (BQL) at 8 hours. Concentrations of
acetone (a primary metabolite) increased until 4.5 (males) or 5 hours (females), achieving peak
concentrations of 0.79 and 1.17 |imol/g, respectively, with acetone concentrations BQL by
24 hours. First-order elimination half-life estimates were similar in both sexes, with mean values
of approximately 0.8 (isopropanol) and 2.6 hours (acetone). Total recovery after iv
administration was approximately 83% in the rat, with 50-55%) of the total dose recovered as
CO2, with a further 20-26% recovered as expired volatiles, and 5—6% recovered in urine.
Recovery from the application site after dermal exposure was similar after both 4-hour and
5-minute periods, with 84-86%) and 86-87%), respectively, recovered. The study authors
concluded that isopropanol underwent rapid dermal absorption in this study.
There are five peer-reviewed and published studies that described the development of a
physiologically based pharmacokinetic (PBPK) model for isopropanol and its major metabolite,
acetone. The model by Clewell et al. (2001) evaluated the kinetics of isopropanol and acetone,
and was developed for oral and inhalation routes for both rats and humans. Models for rats and
humans were parameterized according to values available in the peer-reviewed literature. Oral
uptake rates and metabolic parameters were obtained using model optimization procedures to fit
rates against in vivo pharmacokinetic data in the peer-reviewed literature for oral and inhalation
studies in rats and humans exposed to isopropanol and acetone. Model structure included
compartments for tissues representing major functions including liver (for metabolism) and brain
(for CNS effects). Acetone metabolism parameters for the human were evaluated by comparison
of predictions to observations of a) venous blood isopropanol and acetone concentrations
40
Isopropanol
-------
FINAL
9-16-2014
following oral exposure to unspecified doses (0.6 ml/kg 70% isopropanol in 240 ml water and
0.4 ml/kg 70% isopropanol in 201 ml apple juice), and b) expired air concentrations of
isopropanol and acetone during inhalation exposure to an unspecified concentration for
10 minutes. This PBPK model described by Clewell et al. (2001) was later evaluated by Clark et
al. (2004) as described below.
The manuscript by Gentry et al. (2002) presented an extension of the previous model
(Clewell et al.. 2001) to include physiological/anatomic changes associated with pregnancy in
rats and humans. The base model of Clewell et al. (2001) was used to simulate
non-developmental toxicities in adult rats and extrapolate point of departure (POD) values to
humans. The study authors applied the PBPK model to translate rat neurological NOAEL values
identified from (Burleigh-Flayer et al. (1998); Burleigh-Flaver et al. (1994)). to corresponding
human equivalent exposures and then onto putative toxicity values. The study authors concluded
that isopropanol and acetone may each contribute to CNS effects following isopropanol
exposure. This PBPK model described by Gentry et al. (2002) was also later evaluated by Clark
et al. (2004) as described below.
Gentry et al. (2003) investigated the utilization of the PBPK models for isopropanol and
acetone described by Clewell et al. (2001) and Gentry et al. (2002) to examine several factors
including the extent to which the formation of acetone following isopropanol exposure may
contribute to hematologic and reproductive/developmental toxicity of isopropanol. A
comparison of the combined AUC values for isopropanol and acetone following isopropanol
exposure to the AUC values for acetone alone for acetone-exposed animals led to the conclusion
that the AUC values for acetone alone were unable to account for the developmental toxicity
observed in isopropanol-exposed animals. This suggests that the developmental toxicity in these
animals resulted from combined exposure to isopropanol and acetone. The same was shown to
be true for hematological effects. No neurological data were presented or discussed.
The study by Clark et al. (2004) evaluated the PBPK models for isopropanol and acetone
described earlier by Clewell et al. (2001) and Gentry et al. (2002) based on the following
parameters: model purpose, model structure and biological characterizations, mathematical
descriptions, computer implementation, parameter analysis and model fit, and assessment of
specialized areas. Based on this evaluation, the study authors concluded that the PBPK models
by Clewell et al. (2001) and Gentry et al. (2002) were valid for risk assessment for neurological
and systemic toxicity but not developmental and reproductive effects.
In a study by Huizer et al. (2012). the study authors implemented a PBPK model to test
the influence of variability in human physiological parameters on the blood concentrations of
isopropanol and acetone during and following a simulated 4-hour inhalation exposure to
isopropanol. The analysis concluded that variability for blood concentrations approximated 2- to
3-fold during and following exposure, that uncertainty approximated variability during exposure,
but that uncertainty following exposure may range up to 100-fold at 16 hours following cessation
of the exposure. This study was designed for purposes other than risk assessment, with the
primary goal to highlight the importance of parameter value estimation when evaluating human
interindividual variability.
41
Isopropanol
-------
FINAL
9-16-2014
In a metabolism study by Sipes et al. (1973). the potentiation of carbon tetrachloride
(CCU) hepatotoxicity was investigated in fresh microsomes that were isolated after oral
administration of isopropanol or acetone in the male S-D rat. Isopropanol or acetone was
administered at 16 or 24 hours prior to sacrifice and microsome isolation. Pre-exposure in vivo
to isopropanol or acetone increased covalent binding of 14CCU and A-demethylation of
dimethylnitrosamine in rat microsomes but did not increase CYP450 or cytochrome c reductase
content or the amount of microsomal protein. In vitro addition of isopropanol and acetone to
microsomes was inhibitory in the covalent binding and A-demethylation experiments. Due to the
lack of treatment effect on CYP450 or cytochrome c reductase microsomal content, the
mechanism for increased covalent binding of 14CCU and A'-dem ethylation of
dimethylnitrosamine by isopropanol and acetone was not determined in this study.
Immunotoxicity Study
The immunosuppressive effects of isopropanol were investigated by Desv et al. (2008) in
a series of in vitro and in vivo experiments. In vitro, isopropanol (>0.16%) interfered with the
production of interleukin (IL)-2 in human peripheral lymphocytes and inhibited
IL-2 transcription at a concentration of 0.3% and higher. Isopropanol also inhibited interferon
(IFN)-y release in human peripheral T lymphocytes and natural killer (NK) cells, with virtually
complete inhibition at isopropanol concentrations of 1.2% and 0.6-1.2%), respectively.
Inhibition of IL-2 and IFN-y in vivo in the mouse was demonstrated by delay or protection from
staphylococcal enterotoxin B-induced toxic shock, and reduced cytokine production, after
administration of isopropanol. The study authors noted that a potential implication of these
findings may be immunosuppression after acute isopropanol intoxication; a hypothetical
situation of exposure to isopropanol concentrations of 60-95%) in hand sanitizer products that
were 500- to 1,000-fold more concentrated than the in vitro effective concentration illustrated the
potential for limited and transitory immunosuppressive effects even if poor dermal absorption
were assumed.
Occupational Exposure Studies
Limited information is available regarding occupational exposure of humans to
isopropanol. Shell Oil Co (2000) performed a retrospective study of male workers who were
involved in the manufacture of isopropanol by the low sulfuric acid method (67 to 80%> acid) and
exposed for 6 months to 18 years in Deer Park, TX, between 1943 and 1965. The study
evaluated cancer deaths in this cohort relative to cancer incidence in workers potentially exposed
to isopropyl oil generated by isopropanol manufacture with the high sulfuric acid method (98 to
99% acid). Although a slight excess in all cancer deaths (9 vs. 7.28) and in respiratory cancer
(4 vs. 2.96) was observed for workers exposed over 20 years to isopropanol during the
manufacturing process, there was no clear evidence that isopropanol exposure at this site was
causal to or increased the risk of cancer. A confounding factor in this exposure assessment was
that approximately one-third of the workers in the isopropanol cohort were also involved in the
manufacture of epichlorhydrin.
Another occupational exposure study (Lynch et al.. 1979) conducted a retrospective
analysis of 335 workers involved in ethanol and isopropanol manufacture, as well as a second
cohort with an additional 408 employees (n = 743 total). The incidences of cancer deaths in the
cohorts were compared to expected cancer deaths in white males listed in the Third
U.S. National Cancer Survey conducted in 1975. The incidence of laryngeal cancer was 5-fold
42
Isopropanol
-------
FINAL
9-16-2014
higher than expected, but other disproportionate cancer values were excluded due to low case
numbers (n = 1). The increased incidence of laryngeal cancer was reported as being solely
associated with the high acid ethanol process (worker exposure to diethyl sulfate) and was not
associated with the low acid isopropanol process.
Short-term Studies
Short-term exposure of human subjects to isopropanol in a scientifically controlled
environment has been examined in three inhalation studies. In a peer-reviewed published journal
article study by Smeets et al. (2002). groups of 12 adults (5 males and 7 females, with prior
occupational exposure or control) were administered a single exposure to 0 (control) or
164 mg/m3 isopropanol vapor for 4 hours. Approval for human exposure in this study was
obtained from an Institutional Review Board for the University of Pennsylvania. This exposure
was below the recommended exposure limit of 490 mg/m3 for an 8-hour TWA (ACGIH. 2013).
Overall, sensory irritation was rated as low and weak, although respiration frequency increased
in both groups (possibly the result of a voluntary, not reflexive, change in breathing due to an
unpleasant odor). No differences were noted between the control group and adults with prior
occupational exposure to isopropanol.
Two related peer-reviewed articles of human inhalation studies by Ernstgard et al. (2002)
investigated sex differences due to isopropanol vapor inhalation. Both studies were approved by
the regional ethical committee at the Karolinska Institute. Discomfort in the throat and airways
and fatigue were reported after a single 2-hour exposure to 31 mg/m3 of isopropanol vapor at
rest, with no significant effects on pulmonary function (Ernstgard et al.. 2002). This exposure
was below the recommended exposure limit of 490 mg/m3 for an 8-hour TWA (ACGIH. 2013).
Women were reported to be slightly more sensitive than men to the acute irritant effects of
isopropanol. After a single 2-hour exposure to 350 mg/m3 during light physical activity
(Ernstgard et al.. 2003). sex differences observed in females included lower respiratory uptake,
smaller volume of distribution, slightly shorter half-life of isopropanol in blood, and a higher
apparent total clearance when corrected for body composition. This exposure was below the
recommended exposure limit of 490 mg/m3 for an 8-hour TWA and the short-term exposure
limit of 980 mg/m3 (ACGIH. 2013). Isopropanol levels in exhaled air at 10 minutes
postexposure and times later were increased approximately 4-fold, and acetone blood
concentrations were slightly higher in women. The most marked sex difference was an
approximately 100-fold increase in salivary acetone concentration in women, with no increase in
men. Another marked sex difference was a 10-fold higher in vivo blood:breath ratio in men,
suggestive of sex differences in isopropanol lung metabolism. There was no significant
difference in toxicokinetics between subjects with different genotypes or phenotypes for
metabolic enzymes (i.e., alcohol dehydrogenase and CYP2E1). The study indicated several sex
differences in the inhalation toxicokinetics of isopropanol, and although most of these
differences were consistent with anatomical differences between women and men, differences in
isopropanol concentrations in expired air and acetone in saliva were not correlated to differences
in body build.
Case Reports
Additionally, various case report studies have been published describing the
hospitalization (primarily Emergency Department) and treatment of subjects after various
conditions of exposure (Shettv et al.. 2013; Blow et al.. 2012; Rehman. 2012; Killeen et al..
43
Isopropanol
-------
FINAL
9-16-2014
2011; Clark. 2010; Krieg. 2008; Leeper et al.. 2000; Vivier et al.. 1994; Parker and Lera. 1992;
Rich et al.. 1990; Gaudet and Fraser. 1989; Natowicz et al.. 1985; Daniel et al.. 1981; Mcfadden
andHaddow. 1969). These studies are briefly summarized in Table 5. Isopropanol intoxication
is well documented because isopropanol is inexpensive, readily available, and commonly used in
cleaning and several home remedies/therapies. General symptoms of isopropanol intoxication
included ataxia, lethargy, hypotonia, hyporeflexia, unresponsiveness to pain, and coma. While
symptoms usually resolved after 2-3 days of supportive management, central nervous system
and respiratory depression can result in deep coma. Blood concentrations of isopropanol and
acetone were often determined and followed throughout the course of medical treatment. The
pharmacokinetics of isopropanol and acetone generally were consistent with accepted values. Of
note, the half-life of acetone in one child (<1 year) was approximately half of the accepted adult
value (consistent with 2-fold greater ketone clearance in children) (Parker and Lera. 1992).
Reported cases of intoxication in humans via dermal exposure are likely due to vapor inhalation
and/or compromised skin integrity. In one adult case, intoxication resulted from applying
isopropanol-soaked towels to the face and shoulders during sleep to reduce pain (Leeper et al..
2000). and in two cases in children, intoxication resulted from isopropanol application to the
umbilical cord (Vivier et al.. 1994) or to whole body/nightclothes to aid fever reduction
(Mcfadden and Haddow. 1969).
44
Isopropanol
-------
FINAL
9-16-2014
Table 5. Summary of Case Reports of Human Exposure To Isopropanol
Reference
Number of cases
Exposure
Effects Observed
Comments
Setting/Purpose
Mcfadden and
Haddow CI9691
One infant male
Topical application of
2 quarts of 70% isopropanol
Coma
Whether the isopropanol was
absorbed through the skin or
inhaled could not be
determined.
Medical use
Daniel et al.
(1981)
One adult male
and one adult
female
Ingestion of unknown
amount of 70% isopropanol
in male and 1 pint in female.
Specific effects not reported for male; mental
confusion reported for female.
Isopropanol disappeared from
the blood at a rate following
first-order kinetics in both
cases; blood half-lives were
estimated at 155 and 187 min in
the male and female patients,
respectively.
Intentional abuse
Natowicz et al.
(1985)
One adult female
Ingestion of unknown
amount of 70% isopropanol
Coma
Pharmacokinetic analysis
showed that the elimination of
both isopropanol and its major
metabolite acetone obeyed
apparent first-order kinetics
with half-lives of 6.4 and
22.4 h, respectively
Intentional abuse
Gaudet and
Fraser (1989)
One adult female
Ingestion of unknown
amount of 70% isopropanol
Unresponsiveness, slurred speech, and
disorientation.
The calculated half-life of
isopropanol was 7.3 h
Intentional abuse
Rich et al.
(1990)
Three adult
males
Ingestion of unknown
amount of 70% isopropanol
Apathy, mental confusion, ataxia, hyperreflexia,
and encephalopathy.
No comments
Intentional abuse
Parker and
Lera (1992)
One infant
female
Ingestion of ~4 ounces of
isopropanol (concentration
unknown)
Vomiting, lethargic, and hyporeflexia.
Isopropanol (half-life = 5.8 h)
clearance was similar to values
reported for adults; acetone
(half-life = 10.8 h) was
eliminated twice as rapidly as in
adults
Accidental use
Vivier et al.
(1994)
One infant male
Topical application of
175 mL of 70% isopropanol
Hypotonia, lethargy, and unresponsiveness.
None
Medical use
Leedcr et al.
(2000)
One adult female
Topical application with an
unknown amount of 70%
isopropanol
Syncope and multiple neurological deficits.
None
Medical use
45
Isopropanol
-------
FINAL
9-16-2014
Table 5. Summary of Case Reports of Human Exposure To Isopropanol
Reference
Number of cases
Exposure
Effects Observed
Comments
Setting/Purpose
Blow et al.
(2012)
One adult female
Inhalation of unknown
concentration of isopropanol
Respiratory failure, lung infiltrates, and
hemoptysis.
None
Intentional abuse
Rehman et al.
(2012)
One adult female
Ingestion of unknown
amount of isopropanol
(concentration unknown)
Ketoacidosis, abdominal pain, and vomiting.
None
Intentional abuse
Clark (2010s)
One adult male
Ingestion of ~24 ounces of
70% isopropanol
Coma, poor respiratory effort, dilated pupils, and
significant hypotension.
None
Intentional abuse
Shettv et al.
(2013)
One adult male
Ingestion of unknown
amount of isopropanol-based
sanitizer (concentration
unknown)
Cardiac arrest
Sanitizer contained glycerin and
perfume
Intentional abuse
Kries (2008)
One male child
Transcutaneous absorption
of 24 to 32 oz (0.7 to 0.95 L)
of 70% isopropanol
Coma
None
Medical use
Killeen et al.
(2011s)
One adult female
Ingestion of unknown
amount of 70% isopropanol
Unresponsiveness and pseudorenal insufficiency.
None
Intentional abuse
46
Isopropanol
-------
FINAL
9-16-2014
DERIVATION OF PROVISIONAL VALUES
Table 6 presents a summary of noncancer reference values. Table 7 presents a summary of cancer values.
Table 6. Summary of Noncancer Reference Values for Isopropanol (CASRN 67-63-0)
Toxicity Type (Units)
Species/
Sex
Critical Effect
p-Reference
Value
POD Method
POD
UFc
Principal Study
Subchronic p-RfD (mg/kg-d)
Rabbit/F
Decreased fetal body
weight
2 x 10°
BMDLo5hed
55.2
30
Tvletal. r 19941
Chronic p-RfD (mg/kg-d)
Rabbit/F
Decreased fetal body
weight
2 x 10°
BMDLo5hed
55.2
30
Tvletal. (19941
Subchronic p-RfC (mg/m3)
Rat/F
Increased mean cumulative
motor activity
7 x 10°
NOAELhec
661.8
100
Burleieh-Flaver et al.
(1994)
Chronic p-RfC (mg/m3)
Mice/M
Decreased absolute and
relative testes weights
2 x 10-1
LOAELhec
221
1,000
Burleieh-Flaver et al.
(19971
Table 7. Summary of Cancer Reference Values for Isopropanol (CASRN 67-63-0)
Toxicity Type
Species/Sex
Tumor Type
Cancer Value
Principal Study
p-OSF
NDr
p-IUR
NDr
NDr = Not determined.
47
Isopropanol
-------
FINAL
9-16-2014
DERIVATION OF ORAL REFERENCE DOSES
Derivation of Subchronic Provisional RfD (Subchronic p-RfD)
The developmental study in rabbits by Tyl et al. (1994) is selected as the principal study
for derivation of the subchronic p-RfD. This study was presented in a peer-reviewed journal,
was performed according to good laboratory practice (GLP), and otherwise meets the standards
of study design and performance with regard to numbers of animals, examination of potential
toxicity endpoints, and presentation of information. Details of the study are provided in the
"Review of Potentially Relevant Data" section.
Justification
The effects of oral exposures to isopropanol in animals have been evaluated in one
subchronic-duration study, four developmental toxicity studies, and three reproductive toxicity
studies (see Table 3). As described above, these studies identified a variety of effects on the
liver, kidney, adrenals, spleen, body weight, developing fetus, and reproductive system, with
NOAELs ranging from 120 and 1,948 mg/kg-day and LOAELs ranging from 240 and
2,768 mg/kg-day (Bevan et al.. 1995; Bates et al.. 1994; Tyl et al.. 1994; Pilegaard and
Ladefoged. 1993; BIBRA. 1991. 1988. 1986). These studies were considered for the selection of
the principal study and are described below. Because all of these studies were considered
adequate for the derivation of the subchronic p-RfD and they identified sensitive effects in the
low-dose range, benchmark dose (BMD) modeling was performed on several of the endpoints
(where the data are amenable) and these results are presented below and discussed in detail in
Appendix C. The results of the BMD modeling were then used to identify potential PODs (see
Table 8) for the selection of the principal study and critical effect and derivation of the
subchronic p-RfD.
It is important to note that several studies observed concomitant decreases in water intake
and food consumption (see Table 3). With respect to decreased food consumption, treatment
with alcohol is a known contributor to caloric intake. It is possible that isopropanol treatment
was delivering calories and resulted in a decrease in food consumption, suggesting that this
endpoint is not a direct toxicological effect of isopropanol and therefore not an appropriate
critical effect for reference value derivation. The decrease in water intake is most likely due to
taste aversion, which may also have contributed to a decrease in food consumption. Based on
these reasons, these particular endpoints were not considered for reference value derivation.
In a study by Pilegaard and Ladefoged (1993). 22 male Wistar rats per group were treated
to 0, 870, 1,280, 1,680, and 2,520 mg/kg-day of isopropanol in the drinking water. Increases in
organ weights were observed at various doses: relative liver and adrenal weight at
>1,680 mg/kg-day and relative kidney weight at >1,280 mg/kg-day. The data for these organ
weight changes were subjected to BMD modeling, and the study was considered further for
selection as the principal study for derivation of the subchronic p-RfD. The results of the BMD
modeling are presented below.
BIBRA (1987) reported decreased fetal body weight in male and female fetal rats at
1,605 mg/kg-day as well as a decreased number of fetuses with the fourth sacral arch at
>596 mg/kg-day. For the decreased number of fetuses with the fourth sacral arch in Wistar rats
(BIBRA. 1987). the biological significance of this effect is unknown. Furthermore, the most
common skeletal variations (e.g., poorly ossified frontal bone and supraoccipital bone, etc.)
48
Isopropanol
-------
FINAL
9-16-2014
observed in other developmental toxicity studies were not observed in the BIBRA (1987) study.
These data suggest that a decreased number of fetuses with the fourth sacral arch in Wistar rats
(BIBRA. 1987) is not a relevant toxicological endpoint and was therefore not considered for
derivation of the subchronic p-RfD for isopropanol. However, the data for decreased fetal body
weight were subjected to BMD modeling, and the study was considered further for selection as
the principal study for derivation of the subchronic p-RfD.
In a developmental toxicity study by Bates et al. (1994). maternal CD rats were gavaged
with 0, 200, 700, or 1,200 mg/kg-day of isopropanol from GD 6 to PND 21. The study authors
reported that one dam died in the high-dose group on PND 15, identifying an FEL of
1,200 mg/kg-day with a corresponding NOAEL of 700 mg/kg-day. Because there is no
benchmark response (BMR) for increased mortality in adult animals, these data from Bates et al.
(1994) were not subjected to BMD modeling, nor were mortality data from any other study.
Thus, the Bates et al. (1994) study was not considered further for selection as the principal study
for derivation of the subchronic p-RfD.
Tyl et al. (1994) performed a developmental toxicity study in which dose groups of
25 maternal CD rats were treated by gavage to 0, 400, 800, and 1,200 mg/kg-day of isopropanol
from GDs 6-15. The study authors observed mortality in dams and decreased fetal body weight;
both at >800 mg/kg-day. The data for decreased fetal body weight were subjected to BMD
modeling, and the study was considered further for selection as the principal study for derivation
of the subchronic p-RfD.
In a developmental toxicity study by Tyl et al. (1994). maternal NZW rabbits (15 per
dose group) were gavaged with isopropanol (0, 120, 240, or 480 mg/kg-day) from GDs 6-18.
The study authors reported decreased food consumption and increased mortality in dams at
480 mg/kg-day. Decreased fetal body weight was observed at >240 mg/kg-day. The data for
decreased fetal body weight from this study were subjected to BMD modeling, and the study was
considered further for selection as the principal study for derivation of the subchronic p-RfD.
In a one-generation reproductive toxicity pilot study (BIBRA. 1986). male and female
Wistar rats were treated with isopropanol in the drinking water. The study authors reported
effects in both F0 and F1 rats. In F0 dams, body weight and food consumption were decreased at
both 2,825 and 2,724 mg/kg-day on PND 21. Absolute kidney and relative liver and kidney
weights were increased in dams at both 2,825 and 2,724 mg/kg-day. Also in dams, absolute liver
weight was increased at >2,645 mg/kg-day. In F0 males, food consumption and water intake
were decreased at >711 mg/kg-day. Increased absolute liver and kidney weights were also
observed in males at 1,176 mg/kg-day as well as increased relative liver and kidney weights at
>1,001 mg/kg-day. In F1 rats, decreased pup weight was reported at >1,167 mg/kg-day.
For the BIBRA (1986) study, BMD modeling was not conducted for effects occurring at
a LOAEL 10-fold greater than 240 mg/kg-day, which is the most sensitive, relevant LOAEL
identified in Table 3 (for decreased fetal body weight in female rabbits in Tyl et al.. 1994). With
respect to the endpoint of decreased pup weight in Wistar rats observed in BIBRA (1986). this
study is considered a pilot study (i.e., range-finding study) for the later study by BIBRA (1988).
Compared to the BIBRA (1986) study, the BIBRA (1988) study is considered more complete
because the study authors treated a larger number of dams which resulted in a larger number of
49
Isopropanol
-------
FINAL
9-16-2014
pups. Additionally, the dosimetry could not be calculated for the full duration of the BIBRA
(1986) pilot study because isopropanol intake, food consumption, and water intake were not
determined for either sex during the mating period, nor were these parameters determined for the
dams during the gestational period. The endpoint of decreased pup weight in Wistar rats that
was observed in both the BIBRA (1988). BIBRA (1986) studies could be BMD modeled using
data from the more complete BIBRA (1988) study. The resulting BMDL serves as the potential
POD for decreased pup weight from both the BIBRA (1988). BIBRA (1986) studies. Effects
occurring in F0 adult male rats from this study (e.g., liver weight changes) were not considered
for the derivation of the subchronic p-RfD because the adult male rats were treated longer than
13 weeks. These data were considered in the derivation of the chronic p-RfD as discussed
below. Based on the reasons described here, this study was not considered further for selection
as the principal study for derivation of the subchronic p-RfD.
In an additional one-generation reproductive toxicity study in male and female rats by
BIBRA (1988). similar effects to those observed in the BIBRA (1986) study were noted in F0
and F1 rats. In F0 rats, decreased water intake was reported in males at >625 mg/kg-day and in
females at 1,206 mg/kg-day. Decreased food consumption was observed in F0 males at
>347 mg/kg-day and in females at 1,206 mg/kg-day. Increased relative liver, spleen, and kidney
weights and increased absolute kidney weight were reported in males at 1,030 mg/kg-day.
Increased relative and absolute liver weight in females was observed at 2,768 mg/kg-day. In F1
rats, decreased pup body weight was reported at >668 mg/kg-day. At a dose of
1,902 mg/kg-day, the study authors reported decreased fetal body weight and an increased
number of preimplantation losses in F1 rats. Increased relative liver weight was reported in adult
male and female F1 rats at 2,768 mg/kg-day. As discussed above, effects with LOAELs 10-fold
greater than 240 mg/kg-day were not BMD modeled. Effects occurring in F0 adult male rats
from this study (i.e., liver weight changes) were not considered in the derivation of the
subchronic p-RfD because the adult rats were treated longer than 13 weeks. These data were
considered in the derivation of the chronic p-RfD as discussed below. For all other effects
occurring at lower doses, the data were BMD modeled and the study was considered further for
selection as the principal study for derivation of the subchronic p-RfD.
In a two-generation reproductive toxicity study, Bevan et al. (1995) reported gavage
administration of isopropanol (0, 100, 500, or 1,000 mg/kg-day) to groups of 30 male and
30 female S-D rats for 10-13 weeks before mating and continued through lactation (females) and
until the last litter was sired (males). The study authors noted effects in the F0, Fl, and
F2 generations. In F0 rats, the study authors reported increased absolute and relative liver
weight in males and increased relative liver weight in females (all at 1,000 mg/kg-day). In
Fl rats, increased relative liver weight was reported in adult males at >500 mg/kg-day and
increased relative liver weight in adult females at 1,000 mg/kg-day. The following reproductive
and developmental effects were noted in Fl rats: decreased male mating index at
1,000 mg/kg-day; decreased live birth index at 1,000 mg/kg-day; decreased Day 1
(1,000 mg/kg-day) and Day 4 (>500 mg/kg-day) survival indices. Similar reproductive and
developmental effects were also reported in F2 rats. The study authors reported decreased Day 1
(>500 mg/kg-day), Day 4 (1,000 mg/kg-day), and Day 7 (>500 mg/kg-day) survival indices as
well as decreased lactation index at >500 mg/kg-day in F2 rats. Decreased male pup body
weight was observed in F2 rats at 1,000 mg/kg-day. Effects occurring in F0 and Fl adult rats
(e.g., liver weight changes and decreased male mating index) from this study were not
50
Isopropanol
-------
FINAL
9-16-2014
considered in the derivation of the subchronic p-RfD because the adult rats were treated longer
than 13 weeks. These data were considered in the derivation of the chronic p-RfD as discussed
below. Finally, with respect to decreased survival index, lactation index, and live birth index in
F1 and/or F2 rats (Bevan et al.. 1995). BMD modeling could not be performed due to a lack of
individual pup survival data and variance data. However, Allen et al. (1998) reported BMD
modeling results for the F1 and F2 survival data using a nested logistic model and these data
were considered as potential PODs to derive the subchronic p-RfD for isopropanol. The data for
decreased pup weight in F2 male rats were BMD modeled, and the study was considered further
for selection as the principal study for derivation of the subchronic p-RfD.
Based on the results of the dose-response analysis, the most sensitive effect identified is
decreased fetal body weight in rabbits (Tyl et al.. 1994). As described in Appendix C, all
available continuous models in the EPA Benchmark Dose Software (BMDS version 2.1.2) (U.S.
EPA. 2010) were fit to the number of litters with decreased fetal body weight in rabbits
following treatment with isopropanol on GDs 6-18. Although use of a 10% BMR is the
standard practice, in this case, a 5% BMR is used because the developmental effect
(i.e., decreased fetal body weight) was observed during a potentially sensitive life stage. For
male rabbits and males and females combined, the data for decreased fetal body weight were not
amenable to BMD modeling; a NOAEL/LOAEL approach was employed to identify a potential
POD. For decreased fetal body weight in males and males and females combined, the LOAEL is
480 mg/kg-day based on a >5% decrease in rabbits, with a corresponding NOAEL of
240 mg/kg-day. For decreased fetal body weight in female rabbits, BMD modeling resulted in a
BMDLos of 120 mg/kg-day. Decreased fetal body weight is a common toxicological effect
following oral exposure to isopropanol as observed in four studies in rats. Thus, decreased fetal
body weight in female rabbits is chosen as the critical effect with a BMDLos of
120 mg/kg-day.
51
Isopropanol
-------
FINAL
9-16-2014
Table 8. Potential PODs for Subchronic p-RfD Derivation for
Isopropanol (CASRN 67-63-0)
Study
Species/Study
Sex
Critical
Effect
NOAEL
(mg/kg-d)
LOAEL
(mg/kg-d)
BMDa
(mg/kg-d)
BMDLa
(mg/kg-d)
Pilesaard
and
Ladefosed
(1993)
Rat/Subchronic
M
t Relative
kidney
weight
870
1,280
666b
554b
BIBRA
(1987)
Rat/Developmental
M/F
i Fetal
weight
1,242
1,605
1,348°
847°
Tvl et al.
(1994)
Rabbit/Developmental
F
i Fetal
weight
120
240
284°
120°
Tvl et al.
(1994)
Rat/Developmental
F
i Fetal
weight
400
800
719°
513°
BIBRA
(1988)
Rat/One-Gen
Reproductive
M/F
i Pup weight
NDr
668
563°
402°
Bevan et al.
(1995)
Rat/Two-Gen
Reproductive
M/F
i Survival
index on
PND 4 in
F2 rats
500
1,000
804°
418° as
determined by
Allen et al.
(1998)
aColumn contains lowest BMD(L) values among all endpoints modeled in the respective studies.
bBMR of 10% relative risk.
°BMR of 5% relative risk.
NDr = not determined.
Dosimetric Adjustments:
No duration dosimetric adjustments are made because developmental toxicity studies are
not adjusted for continuous exposure.
In EPA's Recommended Use of Body Weight4 as the Default Method in Derivation of
the Oral Reference Dose (U.S. EPA. 201 lb\ the Agency endorses a hierarchy of approaches to
derive human equivalent oral exposures from data from laboratory animal species, with the
preferred approach being physiologically based pharmacokinetic (PBPK) modeling. Other
approaches may include using some chemical-specific information, without a complete
physiologically based toxicokinetic model. In lieu of chemical-specific models or data to inform
the derivation of human equivalent oral exposures, the U.S. EPA endorses body weight scaling
to the 3/4 power (i.e., BW3/4) as a standard method to extrapolate toxicologically equivalent
doses of orally administered agents from all laboratory animals to humans for the purpose of
deriving a RfD under certain exposure conditions, including when extrapolating from
developmental effects in laboratory animals to humans in those situations where exposure to the
chemical of interest occurred in utero (i.e., dams were administered the chemical of interest
during gestation with effects observed subsequently in the offspring). The use of BW3 4 scaling
for deriving a RfD is also recommended when the observed effects are associated with the parent
compound or a stable metabolite, but not for portal-of-entry effects. A validated human PBPK
model for isopropanol is not available for use in extrapolating doses from rabbits to humans.
The selected critical effect of decreased fetal body weight is associated with the parent
52
Isopropanol
-------
FINAL
9-16-2014
compound or a stable metabolite. Furthermore, this fetal effect is not a portal-of-entry effect.
Therefore, scaling by BW3/4 is relevant for deriving human equivalent doses (HEDs) for this
effect.
Following U.S. EPA (2011b) guidance, the POD for decreased fetal body weight in
female rabbits is converted to a HED through application of a dosimetric adjustment factor
(DAF1) derived as follows:
DAF = (BWa1/4 - BWh1/4)
where
DAF = dosimetric adjustment factor
BWa = animal body weight
BWh = human body weight
Using a BWa of 3.10 kg for female rabbits (U.S. EPA. 1994b) and a BWh of 70 kg for
humans (U.S. EPA. 1988) the resulting DAF is 0.46. Applying this DAF to the BMDLos
identified for the critical effect in fetal rabbits yields a BMDLoshed as follows:
BMDLoshed = 120 mg/kg-day x DAF
= 120 mg/kg-day x 0.46
= 55.2 mg/kg-day
The subchronic p-RfD for isopropanol, based on the BMDLoshed of 55.2 mg/kg-day
(POD) in female fetal rabbits (Tyl et al.. 1994). is derived as follows:
Subchronic p-RfD = BMDLoshed ^ UFc
= 55.2 mg/kg-day -^30
= 2 x 10° mg/kg-day
Tables 9 and 10 summarize the uncertainty factors and the confidence descriptors,
respectively, for the subchronic p-RfD for isopropanol.
1 As described in detail in Recommended Use of Body Weight3/4 as the Default Method in Derivation of the Oral
Reference Dose U.S. EPA (20 lib), rate-related processes scale across species in a manner related to both the direct
(BWm) and allometric scaling (BW3/4) aspects such that BW3/4 ^ BW1/1= BW ' converted to a
DAF = BWa1'4 - BWt1'4.
53 Isopropanol
-------
FINAL
9-16-2014
Table 9. Uncertainty Factors for Subchronic p-RfD for Isopropanol (CASRN 67-63-0)
UF
Value
Justification
UFa
3
A UFa of 3 (10°5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between rats and humans following oral isopropanol exposure. The toxicokinetic
uncertainty has been accounted for by calculation of a human equivalent dose (HED) through
application of a dosimetric adjustment factor (DAF) as outlined in the EPA's Recommended Use of
Bodv Weight3/4 as the Default Method in Derivation of the Oral Reference Dose (U.S. EPA. 201 lb).
UFd
1
A UFd of 1 is applied because the database includes one acceptable two-generation reproductive
toxicity studv in rats (Bevan et al.. 1995) and three acceptable developmental toxicity studies in rats
and rabbits (Bates et al.. 1994; Tvl et al.. 1994) via the oral route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability in
susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of isopropanol in humans.
UFl
1
A UFl of 1 is applied for LOAEL-to-NOAEL extrapolation because the POD is a BMDL.
UFS
1
A UFS of 1 is applied because the critical effect (i.e., decreased fetal body weight) is a
developmental effect. The developmental period is recognized as a susceptible life stage when
exposure during a time window of development is more relevant to the induction of developmental
effects than lifetime exposure (U.S. EPA. 1991).
UFC
30
Composite Uncertainty Factor (UFA x UFD x UFH x UFL x UFS)
Table 10. Confidence Descriptors for Subchronic p-RfD for Isopropanol (CASRN 67-63-0)
Confidence Categories
Designation3
Discussion
Confidence in Study
H
The studv bv the Tvl et al. (1994) is a well-conducted,
peer-reviewed, GLP compliant, and comprehensive study with a
sufficient number of animals that examined a variety of endpoints.
Confidence in Database
M
The database is given medium confidence because there is a
subchronic-duration study in rats, as well as three developmental
toxicity studies in rats and one in rabbits. There are also acceptable
one- and two-generation reproductive toxicity studies in rats.
However, there are no chronic-duration oral studies performed in
animals.
Confidence in Subchronic p-RfDb
M
The overall confidence in the subchronic p-RfD is medium.
aL = low, M = medium, H = high.
bThe overall confidence cannot be greater than the lowest entry in table.
Derivation of Chronic Provisional RfD (Chronic p-RfD)
As described above in the derivation of the subchronic p-RfD, there are three
reproductive toxicity studies (with treatmet durations ranging from 126 to 147 days; Bevan et al..
1995; BIBRA. 1988. 1986) showing effects in adult animals that could be considered for
derivation of the chronic p-RfD, and the effects observed in these studies were BMD modeled to
determine potential PODs.
54
Isopropanol
-------
FINAL
9-16-2014
For the BIBRA (1986) study, the most sensitive effect is increased absolute liver weight
in adult male F0 rats with a BMDLio of 606 mg/kg-day. The most sensitive effect from the
BIBRA (1988) study is a BMDLio of 663 mg/kg-day for increased relative liver weight in F0
adult male rats. For the Bevan et al. (1995) study, the most sensitive effect is increased relative
liver weight in F1 adult male rats with a BMDLio of 197 mg/kg-day. These potential PODs are
all less sensitive than the BMDLos of 120 mg/kg-day for decreased fetal body weight in female
rabbits identified from the developmental study by Tyl et al. (1994) (see Table 11). Thus, based
on the increased sensitivity of decreased fetal body weight in female rabbits compared to the
available chronic-duration data in rats and for the reasons detailed above under the derivation of
subchronic p-RfD, decreased fetal body weight in female rabbits from Tyl et al. (1994) is
chosen as the critical effect for derivation of the chronic p-RfD, with a BMDLos of
120 mg/kg-day.
Table 11. Potential PODs for Chronic p-RfD Derivation for Isopropanol (CASRN 67-63-0)
Study
Species/Study
Sex
Critical Effect
NOAEL
(mg/kg-d)
LOAEL
(mg/kg-d)
BMDa
(mg/kg-d)
BMDLa
(mg/kg-d)
BIBRA
(1986s)
Rat/One-Gen
Reproductive
M
t Absolute liver
weight
1,001
1,176
958b
606b
BIBRA
(1988s)
Rat/One-Gen
Reproductive
M
t Relative liver
weight
625
1,030
l,049b
663b
Bevan et al.
(1995s)
Rat/Two-Gen
Reproductive
M
t Relative liver
weight
100
500
413b
197b
BIBRA
(1987s)
Rat/Developmental
M/F
i Fetal weight
1,242
1,605
1,348°
847°
Tvl et al.
(1994)
Rabbit/Developmental
F
I Fetal weight
120
240
284°
120°
Tvl et al.
(1994s)
Rat/Developmental
F
i Fetal weight
400
800
719°
513°
BIBRA
(1988s)
Rat/One-Gen
Reproductive
M/F
i Pup weight
NDr
668
563°
402°
Bevan et al.
(1995s)
Rat/Two-Gen
Reproductive
M/F
i Survival index
on PND 4 in
F2 rats
500
1,000
804°
418° as
determined
bv Allen et
al. (1998s)
aColumn contains lowest BMD(L) values among all endpoints modeled in the respective studies.
bBMR of 10% relative risk.
°BMR of 5% relative risk.
NDr = not determined.
Dosimetric Adjustments:
No duration dosimetric adjustments are made because developmental toxicity studies are
not adjusted for continuous exposure.
55
Isopropanol
-------
FINAL
9-16-2014
Following U.S. EPA (2011b) guidance, the POD for decreased fetal body weight in
female rabbits is converted to a HED through application of a dosimetric adjustment factor
(DAF2) derived as follows:
DAF = (BWa1/4 - BWh1/4)
where
DAF = dosimetric adjustment factor
BWa = animal body weight
BWh = human body weight
Using a BWa of 3.10 kg for female rabbits (U.S. EPA. 1994b) and a BWh of 70 kg for
humans (U.S. EPA. 1988) the resulting DAF is 0.46. Applying this DAF to the BMDLos
identified for the critical effect in fetal rabbits yields a BMDLoshed as follows:
BMDLoshed = 120 mg/kg-day x DAF
= 120 mg/kg-day x 0.46
= 55.2 mg/kg-day
The chronic p-RfD for isopropanol, based on the BMDLoshed of 55.2 mg/kg-day (POD)
in female fetal rabbits (Tyl et al.. 1994). is derived as follows:
Chronic p-RfD = BMDLoshed ^ UFc
= 55.2 mg/kg-day -^30
= 2 x 10° mg/kg-day
Tables 12 and 13 summarize the uncertainty factors and the confidence descriptors,
respectively, for the chronic p-RfD for isopropanol.
2As described in detail in Recommended Use of Body Weight3/4 as the Default Method in Derivation of the Oral
Reference Dose (U.S. EPA. 201 lb), rate-related processes scale across species in a manner related to both the direct
(BWm) and allometric scaling (BW3/4) aspects such that BW3/4 ^ BW1/1= BW ' converted to a
DAF = BWa1'4 - BWt1'4.
56 Isopropanol
-------
FINAL
9-16-2014
Table 12. Uncertainty Factors for the Chronic p-RfD for Isopropanol (CASRN 67-63-0)
UF
Value
Justification
UFa
3
A UFa of 3 (100 5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between rats and humans following oral isopropanol exposure. The toxicokinetic
uncertainty has been accounted for by calculation of a human equivalent dose (HED) through
application of a dosimetric adjustment factor (DAF) as outlined in the EPA's Recommended Use of
Bodv Weisht3/4 as the Default Method in Derivation of the Oral Reference Dose (U.S. EPA. 201 lb).
UFd
1
A UFd of 1 is applied because the database includes one acceptable two-generation reproductive
toxicity studv in rats (Bevan et al.. 1995) and three acceptable developmental toxicity studies in rats
and rabbits (Bates et al.. 1994; Tvl et al.. 1994) via the oral route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability in
susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of isopropanol in humans.
UFl
1
A UFl of 1 is applied for LOAEL-to-NOAEL extrapolation because the POD is a BMDL.
UFS
1
A UFS of 1 is applied because the critical effect (i.e., decreased fetal body weight) is a
developmental effect. The developmental period is recognized as a susceptible life stage when
exposure during a time window of development is more relevant to the induction of developmental
effects than lifetime exposure (U.S. EPA. 1991).
UFC
30
Composite Uncertainty Factor (UFA x UFD x UFH x UFL x UFS)
Table 13. Confidence Descriptors for Chronic p-RfD for Isopropanol (CASRN 67-63-0)
Confidence Categories
Designation3
Discussion
Confidence in Study
H
The studv bv the Tvl et al. (1994) is a well-conducted,
peer-reviewed, GLP compliant, and comprehensive study with a
sufficient number of animals that examined a variety of endpoints.
Confidence in Database
M
The database is given medium confidence because there is one
subchronic-duration study in rats, as well as three developmental
toxicity studies in rats and one in rabbits. There are also
acceptable one- and two-generation reproductive toxicity studies in
rats. However, there are no chronic-duration oral studies
performed in animals.
Confidence in Chronic
p-RfDb
M
The overall confidence in the chronic p-RfD is medium.
aL = low, M = medium, H = high.
bThe overall confidence cannot be greater than the lowest entry in table.
DERIVATION OF INHALATION REFERENCE CONCENTRATION
Derivation of Subchronic Provisional RfC (Subchronic p-RfC)
The subchronic-duration study in rats by Burleigh-Flaver et al. (1994) is selected as the
principal study for derivation of the subchronic p-RfC. This study was presented in a
peer-reviewed journal and was performed according to good laboratory practice (GLP) and
otherwise meets the standards of study design and performance with regard to numbers of
animals, examination of potential toxicity endpoints, and presentation of information. Details of
the study are provided in the "Review of Potentially Relevant Data" section.
57
Isopropanol
-------
FINAL
9-16-2014
Justification
No published studies investigating the effects of subchronic-duration inhalation exposure
to isopropanol in humans were identified. However, a developmental toxicity study in rats and
three subchronic-duration (13-week) studies in rats or mice utilized inhalation as the route of
exposure. Potential PODs evaluated from these studies are presented below in Table 15.
The most sensitive potential POD from the subchronic-duration inhalation studies is a
NOAEL of 222 mg/m3 for increased relative liver weight in female CD-I mice (Burleigh-Flaver
et al.. 1994). However, this NOAEL is not consistent with other NOAELs observed for
increased relative liver weight in female mice from other inhalation studies. In a
chronic-duration study by Burleigh-Flaver et al. (1997). a LOAEL of 2,211 mg/m3 is identified
for increased relative liver weight in female CD-I mice with a corresponding NOAEL of
1,101 mg/m3. The NOAEL from the subchronic-duration study by Burleigh-Flaver et al. (1994)
is 5-fold lower than that identified from the chronic-duration study by Burleigh-Flaver et al.
(1997) for the same liver endpoint in the same sex and strain of mouse. These data suggest that
the NOAEL of 222 mg/m3 may not be reliable because of its inconsistency with other NOAELs
identified for the same endpoint following even longer exposure durations. The next most
sensitive potential POD is a NOAEL of 661.8 mg/m3 for increased mean cumulative motor
activity in female rats in the chronic study by Burleigh-Flaver et al. (1994). Neither summary
(mean ± SD) nor individual data were provided for endpoints other than kidney histopathology;
therefore, BMD modeling could not be performed on these endpoints from Burleigh-Flaver et al.
(1994). Increased motor activity is a consistently observed effect following inhalation exposure
of isopropanol as it was also observed in female rats exposed to 2,199 mg/m3 for 13 weeks in the
subchronic-duration study by Burleigh-Flaver et al. (1998). Furthermore, the selection of the
NOAEL of 661.8 mg/m3 for increased mean cumulative motor activity in female rats would be
protective against other less sensitive subchronic-duration and developmental toxicity effects due
to isopropanol inhalation listed in Table 14. Thus, increased mean cumulative motor activity
in female rats is chosen as the critical effect with a NOAEL of 661.8 mg/m3.
Table 14. Potential PODs for Subchronic p-RfC Derivation for
Isopropanol (CASRN 67-63-0)
Study
Species/Study
Sex
Critical Effect
NOAEL
(mg/m3)
LOAEL
(mg/m3)
BMC
(mg/m3)
BMCL
(mg/m3)
Burleish-Flaver et al. (1994)
Rat/Subchronic
F
t Motor activity
661.8
2,198
NDr
NDr
Burleish-Flaver et al. (1998)
Rat/Subchronic
F
t Motor activity
NDr
2,199
NDr
NDr
Burleish-Flaver et al. (1994)
Mouse/Subchronic
F
t Relative liver
weight
222
661.8
NDr
NDr
Nelson etal. ^1988")
Rat/Developmental
M
i Fetal weight
2,516
5,048
2,537a
l,907a
aBMR of 5% relative risk.
NDr = not determined.
58
Isopropanol
-------
FINAL
9-16-2014
Adjusted concentrations for daily exposure:
The following dosimetric adjustments have been made for inhalation exposures.
Dosimetric adjustment for the 1,508-ppm group is presented as an example below.
(EXPOSUREhec, exresp) = [PPM conversion]
x [average daily concentration conversion]
x [blood gas partition coefficients (BGPC)*]
= (PPM) x (MW 24.45) x (hours exposed 24)
x (days exposed ^ total days) x (BGPC)
= 1,508 ppm x (60.09 - 24.45) x (6 - 24) x (65 - 91) x 1
= 661.8 mg/m3
*BGPC = [(Hb/g)a] ^ [(Hb/g)h]
= (1,290)a (848)h as determined by Kaneko et al. (1994)
= 1.5 (therefore, the default value of 1 is used for a BGPC ratio >1).
Although there is a valid PBPK model for isopropanol (Clewell et al..
2001) for converting animal concentrations to human, the application of
PBPK models is outside of the scope of a PPRTV assessment.
The subchronic p-RfC for isopropanol, based on the NOAELhec of 661.8 mg/m3 is
derived as follows:
Subchronic p-RfC = NOAELhec ^ UFc
= 661.8 mg/m3 100
= 7 x 10° mg/m3
Tables 15 and 16 summarize the UFs and the confidence descriptors, respectively, for the
subchronic p-RfC for isopropanol.
Table 15. Uncertainty Factors for Subchronic p-RfC for Isopropanol (CASRN 67-63-0)
UF
Value
Justification
UFa
3
A UFa of 3 (100 5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between rats and humans following inhalation exposure to isopropanol. The
toxicokinetic uncertainty has been accounted for by calculation of a human equivalent concentration
(HEC) as described in the RfC methodology (U.S. EPA. 1994b).
UFd
3
A UFd of 3 is applied because the database includes one acceptable developmental toxicity study in
rats (Nelson et al.. 1988) but no acceptable two-generation reproductive toxicity studies via the
inhalation route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability in
susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of isopropanol in humans.
UFl
1
A UFl of 1 is applied for LOAEL-to-NOAEL extrapolation because the POD is a NOAEL.
UFS
1
A UFS of 1 is applied because a subchronic-duration study was selected as the principal study.
UFC
100
Composite Uncertainty Factor (UFA x UFD x UFH x UFL x UFS)
59
Isopropanol
-------
FINAL
9-16-2014
Table 16. Confidence Descriptors for Subchronic p-RfC for Isopropanol (CASRN 67-63-0)
Confidence Categories
Designation"
Discussion
Confidence in Study
H
The Drincioal studv (Burleieh-Flaver et al.. 1994) assessed an
acceptable number of endpoints including body weight, motor
activity, food consumption and water intake, blood chemistry,
organ weights, and histopathology. The exposure duration of
13 weeks is sufficient to determine subchronic-duration toxicity.
Confidence in Database
M
The database includes two subchronic-duration studies in rats and
one in mice. There was a single developmental toxicity study in
rats. There were also one carcinogenic/chronic study in rats and
one in mice. A two-generation reproductive toxicity study is not
available.
Confidence in Subchronic p-RfCb
M
The overall confidence in the subchronic p-RfC is medium.
aL = low, M = medium, H = high.
bThe overall confidence cannot be greater than lowest entry in table.
Derivation of Chronic Provisional RfC (Chronic p-RfC)
The chronic-duration inhalation study in mice by Burleigh-Flaver et al. (1997) is selected
as the principal study for derivation of the chronic p-RfC. This study was presented in a
peer-reviewed journal and was performed according to good laboratory practice (GLP) and
otherwise meets the standards of study design and performance with regard to numbers of
animals, examination of potential toxicity endpoints, and presentation of information. Details of
the study are provided in the "Review of Potentially Relevant Data" section.
Justification
No published studies investigating the effects of chronic-duration inhalation exposure to
isopropanol in humans were identified. A developmental toxicity study in rats (Nelson et al..
1988) and chronic-duration carcinogenicity studies (Burl eigh-Fl aver et al.. 1997) in rats
(104 weeks) and mice (78 weeks) utilized inhalation as the route of exposure. For changes in
organ weight in rats and mice observed in the Burl eigh-Fl aver et al. (1997) studies, only those
noted at the terminal euthanasia were considered for candidate PODs. For organ weight changes,
the EPA Benchmark Dose Software (BMDS version 2.1.2) (U.S. EPA. 2010) continous models
were fit to the data. The most sensitive potential POD from these studies is a LOAEL of
221 mg/m3 for decreased absolute and relative testes weights in male mice following 78 weeks
of exposure (Burleigh-Flaver et al.. 1997); these data were not amenable to BMD modeling.
Testicular effects due to isopropanol treatment were also observed in other studies as indicated in
Table 3. Testicular seminiferous tubule atrophy was observed (unknown statistical significance)
in F344 rats at 2,211 mg/m3 at the interim sacrifice in the chronic-duration cancer inhalation
study by Burleigh-Flaver et al. (1997). The incidence of seminal vesicle enlargement was also
statistically significantly increased at 2,211 mg/m3 in male mice from this study. Additionally,
increased relative testes weight was observed following oral exposure in rats at 2,520 mg/kg-day
in the subchronic-duration study by Pilegaard and Ladefoged (1993). and was also observed at
2,768 mg/kg-day in F1 male rats in the reproductive study by BIBRA (1988). In the other oral
reproductive studies in rats by BIBRA (1986) and Bevan et al. (1995). testes weight was not
measured so it is possible that effects on testes weight could have been observed in those studies.
60
Isopropanol
-------
FINAL
9-16-2014
There were also reproductive effects rats treated with isopropanol. In the oral reproductive study
by Bevan et al. (1995). the male mating index was statistically decreased at 1,000 mg/kg-day in
S-D rats, and these reproductive effects due to isopropanol exposure could possibly be related to
testicular effects also caused by this chemical.
The next most sensitive effect is increased relative liver weight in male rats with a
BMCLio of 262 mg/m3 (Burleigh-Flaver et al.. 1997). Absolute liver weight was also
statistically significantly increased at the two highest concentrations but there were also
concominant increases in body weight that could have contributed to this effect, thus this effect
was not modeled.
An increase in the incidence and severity of renal lesions such as tubular proteinosis,
glomerulosclerosis, interstitial nephritis, interstitial fibrosis, and transitional cell hyperplasia in
mid- and high-concentration rats (both sexes) was also observed following inhalation of
isopropanol, with incidence and severity greater in males compared to females (Burleigh-Flaver
et al.. 1997). However, a potential confounding factor in the biological relevance of some of
these renal lesions in both male and female rats may be the high incidence rates (>50%) that
occurred in the control animals. For interstitial fibrosis in male rats, the incidence rate in the
controls was 64%. For interstitial nephritis in male and female rats, the controls displayed
incidences of 76% and 58%, respectively. Due to the high incidence rates in the control groups,
these specific lesions were not considered for selection of a POD to derive the chronic p-RfC.
All other lesions occurring in male and female rats that were statistically significantly increased,
were considered for selection of a POD. The EPA Benchmark Dose Software (BMDS
version 2.1.2) (U.S. EPA. 2010) dichotomous models were fit to the data for incidences of these
renal lesions in male and female rats. BMC input data for these incidences are presented in
Tables B-19 (male rats) and B-20 (female rats). The most sensitive of these renal lesions is
transitional cell hyperplasia in the male rat with a BMCLio of 291 mg/m3.
There were also developmental effects (e.g., decreased fetal body weight, increased
malformations, etc.) in rats due to inhalation exposure of isopropanol as reported by Nelson et al.
(1988). The most sensitive of these developmental effects is decreased fetal body weight in male
rats with a BMDLs of 1,907 mg/m3.
Of the potential PODs for derivation of the chronic p-RfC, the most sensitive is a LOAEL
of 221 mg/m3 for decreased absolute and relative testes weights in male mice (Burleigh-Flaver et
al.. 1997). As described above, there is large support for the testes being a target organ of
isopropanol-induced toxicity. Furthermore, the selection of the LOAEL of 221 mg/m3 for
decreased absolute and relative testes weights in male mice would be protective against other
less sensitive chronic-duration and developmental effects due to isopropanol inhalation. Thus,
decreased absolute and relative testes weights in male mice is chosen as the critical effect
with a LOAEL of 221 mg/m3.
Adjusted concentrations for daily exposure:
The following dosimetric adjustments have been made for inhalation exposures.
Dosimetric adjustment for the 500-ppm group is presented as an example below.
61
Isopropanol
-------
FINAL
9-16-2014
(EXPOSUREhec, exresp) = [PPM conversion]
x [average daily concentration conversion]
x [blood gas partition coefficients (BGPC)*]
= (PPM) x (MW ^ 24.45) x [(hours exposed ^ 24)
x (days exposed ^ total days)] x (BGPC)
= 504 ppm x (60.09 - 24.45) x (6 - 24) x (390 - 546) x 1
= 221 mg/m3
*BGPC = [(Hb/g)a] ^ [(Hb/g)h]
= (1,290)a (848)h as determined by Kaneko et al. (1994).
= 1.5 (therefore, the standard value of 1 is used for a BGPC ratio >1).
Although there is a valid PBPK model for isopropanol (Clewell et al..
2001) for converting animal concentrations to human, the use of PBPK is
outside of the scope of a PPRTV.
The chronic p-RfC for isopropanol, based on the LOAELhec of 221 mg/m3 for decreased
absolute and relative testes weights in male mice (Burleigh-Flaver et al.. 1997). is derived as
follows:
Chronic p-RfC = LOAELhec ^ UFc
= 221 mg/m3 - 1,000
= 2 x 10"1 mg/m3
Tables 17 and 18 summarize the uncertainty factors and the confidence descriptors,
respectively, for the chronic p-RfC for isopropanol.
Table 17. Uncertainty Factors for Chronic p-RfC for Isopropanol (CASRN 67-63-0)
UF
Value
Justification
UFa
3
A UFa of 3 (100 5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between rats and humans following inhalation exposure to isopropanol. The
toxicokinetic uncertainty has been accounted for by calculation of a human equivalent concentration
(HEC) as described in the RfC methodology (U.S. EPA. 1994b).
UFd
3
A UFd of 3 is applied because the database includes one acceptable developmental toxicity study in
rats (Nelson et al.. 1988) but no acceptable two-generation reproductive toxicity studies via the
inhalation route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability in
susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of isopropanol in humans.
UFl
10
A UFl of 10 is applied for LOAEL-to-NOAEL extrapolation because the POD is a LOAEL.
UFS
1
A UFS of 1 is applied because a chronic-duration study was selected as the principal study.
UFC
1,000
Composite Uncertainty Factor (UFA x UFD x UFH x UFL x UFS)
62
Isopropanol
-------
FINAL
9-16-2014
Table 18. Confidence Descriptors for Chronic p-RfC for Isopropanol (CASRN 67-63-0)
Confidence Categories
Designation3
Discussion
Confidence in Study
H
The Drincioal studv (Burleieh-Flaver et al.. 1997) assessed an
acceptable number of endpoints including survival, body weight,
organ weight (kidneys, liver, testes, brain, and lungs), urinalysis and
urine chemistry data, and histopathology of numerous tissues. The
exposure durations of 104 and 78 wk in the rat and the mouse are
considered sufficient to determine chronic toxicity.
Confidence in Database
M
The database includes two subchronic-duration studies in rats and
one in mice. There was a single developmental toxicity study in
rats. There were also one carcinogenic/chronic study in rats and
one in mice. A two-generation reproductive toxicity study is not
available.
Confidence in Chronic p-RfCb
M
The overall confidence in the chronic p-RfC is medium.
aL = low, M = medium, H = high.
bThe overall confidence cannot be greater than lowest entry in table.
CANCER WOE DESCRIPTOR
Table 19 identifies the cancer WOE descriptors for isopropanol. No carcinogenicity
studies in humans or animals by the oral route have been found. Human studies do not provide
exposure-response data for assessing carcinogenicity of isopropanol following inhalation
exposure. Inadequate epidemiology data are available to assess the potential for isopropanol to
act as a carcinogen in exposed humans. An association between upper respiratory cancer and
strong acid isopropanol processing jobs/factories was noted but was inadequate to assess for
isopropanol alone. A peer-reviewed journal article by Burleigh-Flaver et al. (1997) reported a
chronic-duration inhalation carcinogenicity study conducted with the F344 rat and the CD-I
mouse. No increases in the frequency of neoplastic lesions were observed in the mouse (both
sexes) or the female rat. An increased incidence in testicular interstitial (Leydig) cell adenomas
was noted in the male rat, but the finding was discounted as an artifact due to a low incidence in
the control group relative to historical incidence for male F344 control animals in the study
authors' laboratory and in NTP two-year carcinogenicity studies conducted with this rat strain.
The study authors stated that".. .interstitial cell adenomas of the testes probably represent foci of
marked hyperplasia rather than autonomous growth, because these adenomas originate as
multiple foci of hyperplasia, and the transformation from hyperplasia to adenoma represents a
continuous spectrum of morphologic change occurring within the testes of aged F344 male rats."
Interstitial cell tumors of the testes were also noted as the most frequently observed spontaneous
tumor in aged male F344 rats. Taken together, and in the absence of information to indicate
otherwise, there is inadequate information to assess carcinogenic potential for isopropanol
following oral exposure. For inhalation exposure, isopropanol is considered not likely to be
carcinogenic to humans.
63
Isopropanol
-------
FINAL
9-16-2014
Table 19. Cancer WOE Descriptor for Isopropanol (CASRN 67-63-0)
Possible WOE
Descriptor
Designation
Route of Entry
(Oral, Inhalation, or
Both)
Comments
"Carcinogenic to
Humans "
NS
NA
There are no human data to support this.
"Likely to be
Carcinogenic to
Humans "
NS
NA
There are insufficient data in animals and no data in
humans to support this.
"Suggestive
Evidence of
Carcinogenic
Potential"
NS
NA
There are insufficient animal data to support this.
"Inadequate
Information to
Assess
Carcinogenic
Potential"
Selected
Oral
There is adequate information available to assess
the carcinogenic potential of isopropanol in
animals following inhalation exposure but no
information is available for the oral route.
"Not Likely to be
Carcinogenic to
Humans"
Selected
Inhalation
Based on two studies (Burleish-Flaver et al.. 1997)
which observed no positive association between
relevant tumors and isopropanol inhalation
exposure in both sexes of rats and mice and an
unrelated increase in testes tumors in male rats,
isopropanol is considered not likely to be
carcinogenic to humans for the inhalation route.
NA = not applicable, NS = not selected.
MODE-OF-ACTION DISCUSSION
The Guidelines for Carcinogen Risk Assessment (U.S. EPA. 2005) define mode of action
".. .as a sequence of key events and processes, starting with interaction of an agent with a cell,
proceeding through operational and anatomical changes, and resulting in cancer formation."
Examples of possible modes of carcinogenic action for any given chemical include
".. .mutagenicity, mitogenesis, inhibition of cell death, cytotoxicity with reparative cell
proliferation, and immune suppression" (p. 1-10).
Isopropanol tested negative for mutagenicity in Ames assays (IARC. 1999; Zeiger et al..
1992). a meiotic nondisjunction and aneuploidy assay, gene mutation tests in CHO cells, a
mouse micronucleus assay, and a sister chromatid exchange assay in Chinese hamster V79 cells
(IARC. 1999). In the absence of positive results, isopropanol is not considered to be mutagenic.
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES
Derivation of Provisional Oral Slope Factor (p-OSF)
Lack of human and animal data preclude derivation of a p-OSF.
64
Isopropanol
-------
FINAL
9-16-2014
Derivation of Provisional Inhalation Unit Risk (p-IUR)
Because there is no evidence of carcinogenic potential for isopropanol following
exposure via the inhalation route and it is considered not likely to be carcinogenic to humans,
derivation of a p-IUR is precluded.
65
Isopropanol
-------
FINAL
9-16-2014
APPENDIX A. PROVISIONAL SCREENING VALUES
No provisional screening values were derived.
66
Isopropanol
-------
FINAL
9-16-2014
APPENDIX B. DATA TABLES
Table B-l. Relative Organ Weights and Absorbance in the Dorsal Hippocampus in Male
Rats Exposed to Isopropanol in Drinking Water for 12 Weeks"
Parameter
Isopropanol (mean intake mg/kg-d)
0
870
1,280
1,680
2,520
Relative Organ Weight g/100 g (± SD)
Organ
Liver
(% increase)
2.90 ±0.24
3.02 ±0.12
3.15 ±0.24* (|9)b
3.22 ±0.20** (fll)
3.26 ±0.25*** (f 12)
Kidneys
(% increase)
0.483 ±0.033
0.515 ±0.036
0.582 ±0.052***
(|20)
0.601 ±0.038***
(T24)
0.654 ±0.061***
(T35)
Adrenals
(% increase)
10.9 ± 1.5
11.5 ± 1.0
12.5 ± 1.3
13.8 ± 1.9*** (|27)
14.6 ± 1.7*** (|34)
Testes
(% increase)
0.785 ±0.086
0.741 ±0.072
0.736 ±0.065
0.788 ±0.091
0.888 ±0.084** (f 13)
Heart
0.251 ±0.020
0.251 ±0.016
0.246 ±0.013
0.257 ±0.018
0.259 ±0.022
Spleen
0.157 ±0.020
0.163 ±0.030
0.160 ±0.015
0.169 ±0.023
0.153 ±0.022
Absorbance (Mean ± SD)
CA1
0.139 ±0.014
ND
ND
ND
0.127 ±0.011
CA3
0.149 ±0.008
ND
ND
ND
0.139 ±0.014
Hilus
0.186 ±0.024**c
ND
ND
ND
0.163 ±0.021**c
aData were obtained from Tables 1 and 2 on page 329 in Pilegaard and Ladefoged (19931.
bDirection of percentage difference from control is included in parentheses.
"Difference between the hilar and CA1 regions.
n = 12/group, except for the high-dose group (n= 11).
*p < 0.05.
**p < 0.01.
***p < 0.001.
67
Isopropanol
-------
FINAL
9-16-2014
Table B-2. Effects of Daily Gestational Oral Exposures in the Cesarean Section Data from
Rats Administered Isopropanol by Gavage on GDs 6-16a
Parameter
Exposure Group (mg/kg-d)
0
596
1,242
1,605
All litters («)''
17
18
18
19
Corpora lutea per dam0
13 ±2.54
14.2 ±2.23
12.7 ± 1.41
12.2 ±2.93
Implantation sites per litter0
11.9± 1.50
11.3 ± 2.19
11.7 ± 1.88
11.1 ± 3.15
Preimplantation losses0
1.4 ±2.83
2.9 ±4.32
1.0 ± 1.61
1.11 ± 1.52
Live fetuses0
11.1 ± 2.34
10.2 ±3.19
11.0 ± 2.11
10.6 ±3.31
Early resorptions0
0.8 ± 1.20
1.1 ± 1.37
0.6 ±0.85
0.4 ±0.6
Late resorptions0
0.1 ±0.24
0.1 ±0.24
0.1 ±0.24
0.1 ±0.32
Postimplantation losses0
0.8 ± 1.38
1.2 ± 1.58
0.7 ±0.84
0.5 ±0.77
Mean % implantations
92.9
85
93.9
90.8
No. of females with postimplantation
losses
7
13
9
6
Litter weight (g)°
40.1 ±8.99
38.7 ±7.87
37.6 ±6.77
37.0 ±6.49
Fetal sex ratio (M:F)
1.05
1.26
1.23
1.35
Mean fetal body weight per litter (g)c
All fetuses
3.59 ±0.202
3.58 ±0.252
3.43 ± 0.221* (4,5)
3.35 ± 0.282** (|7)
Male fetuses
3.71 ±0.205
3.69 ±0.180
3.54 ±0.233
3.44 ±0.254
Female fetuses
3.47 ±0.214
3.48 ±0.260
3.32 ±0.228
3.24 ±0.319
aData were obtained from Table 2 on page 464 in Faberet al. (20081.
bIncludes all dams with litters on GD 20.
°Reported as mean ± SD.
*p < 0.01.
**p < 0.001.
68
Isopropanol
-------
FINAL
9-16-2014
Table B-3. Effects of Daily Gestational Oral Exposures in the Cesarean Section Data from
Rats Administered Isopropanol by Gavage on GDs 6-15a
Parameter
Exposure Group (mg/kg-d)
0
400
800
1,200
All litters (/?/'
(23)
(25)
(23)
(22)
Corpora lutea per dam0
14.9 ±0.4
15.4 ±0.4
14.6 ±0.4
14.4 ±0.4
Implantation sites per litter0
14.4 ±0.4
14.9 ±0.4
14.2 ±0.3
14.1 ±0.4
Percentage preimplantation loss0
4.0 ± 1.2
4.2 ± 1.0
4.0 ± 1.0
2.9 ±0.9
Percentage resorptions per litter0
1.5 ±0.6
1.4 ±0.6
1.8 ± 1.0
4.1 ± 1.3
No. (%) litters with resorptions
5 (21.7)
5 (20.0)
3 (13.0)
9 (40.9)
Percentage late fetal deaths per litter0
0.0
0.0
0.0
0.0
No. litters with late fetal deaths
0
0
0
0
Percentage adversely affected
implants per litter0'4 {
1.8 ±0.6
3.8 ±1.1
2.8 ± 1.1
5.7 ± 1.4
No. (%) litters with adversely affected
implants
6 (26.1)
9 (36.0)
6 (26.1)
13 (59.1)
Live litters (nf
(23)
(25)
(23)
(22)
Live fetuses per litter0
14.0 ±0.4
14.7 ±0.4
13.9 ±0.3
13.5 ±0.4
Percentage male fetuses per litter01
44.4 ±2.9
50.2 ±2.8
56.0 ±2.2**
46.9 ±2.4
Average fetal body weight per litter0
All fetusesff, }}}
3.866 ±0.051
3.794 ±0.058
3.682 ±0.050
3.559 ±0.075**
Male fetusesff, {{{
3.972 ±0.055
3.875 ±0.052
3.762 ±0.052*
3.649 ±0.076**
Female fetusesff, {{{
3.791 ±0.050
3.717 ±0.065
3.574 ±0.053*
3.487 ±0.074**
aData were obtained from Table 1 on page 143 in Tvl et al. (19941.
bIncludes all dams pregnant at sacrifice; litter size = no. implantation sites per dam.
°Reported as mean ± standard error of the mean.
dAdversely affected = nonlive (late fetal deaths plus resorptions) plus malformed.
"Includes only dams with live fetuses; litter size = no. live fetuses per dam.
*p < 0.05; Dunnett's test.
**p < 0.01; Dunnett's test.
tp < 0.05; ANOVA.
ft/? < 0.01; ANOVA.
%p< 0.05; test for linear trend.
}}}/? < 0.001; test for linear trend.
69
Isopropanol
-------
FINAL
9-16-2014
Table B-4. Average Fetal Body Weight Per Litter of Rabbits from Dams treated
on GDs 6-18a
Parameter
Exposure Group (mg/kg-d)
0
120
240
480
All litters («)''
15
11
15
11
Live litters (nf
15
11
15
11
Average fetal body weight per litterd
All fetuses
49.71 ± 1.80
49.71 ±0.82
47.92 ± 1.56
46.48 ±3.31
Male fetuses
49.68 ±2.23
50.42 ±0.99
48.99 ± 1.6
46.04 ±2.94
Female fetuses{
49.75 ± 1.88
48.68 ± 1.06
46.65 ± 1.69
42.79 ±3.05
aData were obtained from Tvl et al. (19941.
includes all dams pregnant at sacrifice; litter size = no. implantation sites per dam.
includes only dams with live fetuses; litter size = no. live fetuses per dam.
dReported as mean ± standard error of the mean.
%p< 0.05; test for linear trend.
70
Isopropanol
-------
FINAL
9-16-2014
Table B-5. Mean Body Weight (g) and Food (g/rat-day) Consumption and Water
(mL/rat-day) Intake in Postpartum Parental (F0) Female Rats Exposed to Isopropanol in
Drinking Water"
Postpartum
Day
Isopropanol (mean intake mg/kg-db)
0
1,167
2,645
2,825
2,724
Weight (g) in the Female Rat (± SD)
1 (% change)
242.7 ± 15.26
248.9 ±24.79
236.3 ± 19.69
236.8 ± 16.18
223.8 ±21.53
4 (% change)
259.2 ± 14.21
263.4 ± 12.57
259.4 ± 18.65
245.1 ±15.82* (45)c
226.0 ± 12.14*** (|13)
7 (% change)
270.3 ± 15.87
279.1 ± 11.44
269.1 ±20.81
249.1 ± 12.29** (|8)
230.1 ± 10.25*** (|15)
14 (% change)
289.1 ±20.25
299.4 ±7.17
287.5 ± 20.00
255.4 ± 13.34*** (J, 12)
230.2 ±20.02*** (|20)
21 (% change)
282.8 ±23.00
289.4 ± 12.76
289.9 ±20.26
244.9 ± 17.93*** (|13)
226.4 ± 33.93*** (420)
Food consumption (g/rat-day) in the Female Rat (± SD)
Premating
16.2 ±2.11
15.4 ± 1.65
14.7 ± 1.85
14.0 ± 1.97*
12.7 ±2.36**
1-4
26.9 ±7.29
30.6 ±4.67
30.1 ±3.73
25.1 ±6.01
16.5 ±4.35***
4-7
45.5 ± 12.95
43.5 ± 6.19d
39.6 ±5.31
30.0 ±6.78***
21.0 ±7.60***
7-11
47.2 ±8.38
52.0 ±9.02
45.8 ±8.86
34.7 ±8.85**
24.7 ±7.85***
11-14
55.5 ± 13.26
57.9 ± 10.38
54.7 ±7.56
38.7 ±9.96**
24.7 ± 9.66***
14-18
63.0 ± 12.50
63.1 ±7.97
58.4 ±6.13
43.3 ± 12.84***
23.9 ±6.46***
18-21
75.6 ± 19.00
78.1 ± 10.48
66.1 ± 11.00
43.7 ± 12.28***
25.8 ± 8.65***
Water Intake (mL/rat-day) in the Female Rat (± SD)
Premating
28.3 ±2.21
27.7 ±0.92
24.2 ± 1.87***
17.1 ±2.24***
14.3 ± 1.61***
1-4
51.6 ± 11.3
52.3 ±7.33
49.2 ±6.13
35.2 ± 5.13***
28.5 ±3.07***
4-7
65.6 ± 16.55
75.0 ± 11.22*
61.0 ±8.29
40.6 ±6.12***
30.5 ±4.59***
7-11
83.6 ± 18.00
90.2 ±8.84
79.7 ± 15.29
44.5 ± 14.46***
36.1 ± 14.01***
11-14
98.1 ±26.06
98.0 ± 10.18
87.8 ± 10.49
49.4 ± 12.00***
32.1 ±6.60***
14-18
96.5 ±20.33
102.0 ± 12.59
88.5 ± 16.77
54.9 ± 15.47***
32.0 ±7.44***
18-21
122.9 ±29.88
122.9 ± 15.66
112.1 ± 15.85
56.4 ± 16.76***
34.7 ± 10.12***
aData were obtained from Tables 8, 9, and 10 on pages 47-49 in BIBRA (19861.
bMean intake conversion data were obtained from Table 12 on page 51 in BIBRA (19861.
Direction of percentage difference from control is included in parentheses.
dThis number was illegible in the available copy of the document and may have been 43.5 ± 8.19.
n = 9-10/group.
Figures marked with asterisk(s) differ significantly from control by ANOVA and the procedure of Least Significant
Difference, and Student's /-test for the mean premating value.
*p < 0.05.
**p < 0.01.
***p < 0.001.
71
Isopropanol
-------
FINAL
9-16-2014
Table B-6. Litter Size, Pup Survival, and Pup Weight of F1 Animals Produced by Paired
Rats Exposed to Isopropanol in Drinking Water During the Postpartum Period"
Parameters
Isopropanol Exposure Group (mean intake mg/kg-db)
0
1,167
2,645
2,825
2,724
No. of litters
9
10
10
10
9
No. pups at Day 1
84
106
92
68
37
Mean no. pups/litter at Day 1
9.3
10.6
9.2
6.8
4.1
No. of pups at Day 21
82
105
90
62
31
Mean no. pups/litter at Day 21
9.1
10.5
9.0
6.2
3.4
Mean pup survival/litter (%)+
98.1
98.9
97.8
85.9
63.5
Total pup survival*
97.6
99.0
97.8
91.2
83.8
No. litters with 100% survival""
3
2
2
5
6
Mean pup weight/litter0
48.6 ±5.42
45.3 ±2.62
43.4 ±4.54*
38.4 ±5.04***
29.8 ±4.63***
aData were obtained from BIBRA (19861.
bMean intake conversion data were obtained from Table 12 on page 51 in BIBRA (19861.
°Mean ± SD.
Calculated from individual data as Mean no. pups Day 21 Mean no. pups Day 1 x 100.
"Calculated as: Total pups Day 21 Total pups Day 1 x ioo.
""Including animals with dead pups on Day 1.
*p < 0.05.
***p < 0.001.
72
Isopropanol
-------
FINAL
9-16-2014
Table B-7. Mean Absolute and Relative Organ Weights in Parental (F0) Rats Exposed to
Isopropanol in Drinking Water for a Pilot One-Generation Reproductive Study"
Parameter
Isopropanol (mean intake mg/kg-db)
0
317
711
1,001
1,176
Male
Absolute Weight (g)
Liver
10.64 ±0.631
10.74 ± 1.203
10.96 ±0.912
11.49 ± 1.181
12.00 ± 1.358**
Kidney
2.56 ±0.119
2.54 ±0.227
2.59 ±0.204
2.78 ±0.213*
2.89 ±0.234***
Terminal Body
Weight (g)
416.8 ± 18.16
427.1 ±39.02
419.3 ±22.14
402.5 ±37.93
412.1 ±37.11
Relative Weight (g/100 g bw)
Liver
(% change)
2.56 ±0.158
2.51 ±0.121
2.62 ±0.166
2.86 ±0.142***
(|12)b
2.91 ±0.185***
(t 14)
Kidney
(% change)
0.61 ±0.031
0.60 ±0.034
0.62 ±0.035
0.69 ±0.055***
(t 13)
0.70 ±0.039***
(t 15)
Parameter
Isopropanol (mean intake mg/kg-db)
0
1,167
2,645
2,825
2,724
Female
Absolute Weight (g)
Liver
6.90 ±0.928
6.96 ±0.320
7.61 ±0.657*
8.23 ± 1.072***
7.89 ±0.645**
Kidney
1.58 ±0.121
1.63 ±0.090
1.73 ±0.137
1.92 ±0.242***
1.83 ±0.327**
Terminal Body
Weight (g)
232.4 ± 17.01
236.3 ±8.18
241.4 ±20.19
226.0 ± 13.73
225.0 ± 18.06
Relative Weight (g/100 g bw)
Liver
(% change)
2.93 ± 0.403
2.95 ±0.135
3.17 ±0.320
3.66 ±0.590***
(T25)
3.54 ±0.494** (|21)
Kidney
(% change)
0.68 ±0.061
0.69 ±0.039
0.72 ±0.069
0.85 ±0.136***
(T25)
0.82 ±0.169** (|21)
aData were obtained from Table 16 on page 55 in BIBRA (19861.
bDirection of percentage difference from control is included in parentheses.
Figures marked with asterisk(s) differ significantly from control by ANOVA and the procedure of Least Significant
Difference.
*p < 0.05.
**p < 0.01.
***p < 0.001.
73
Isopropanol
-------
FINAL
9-16-2014
Table B-8. Effects of Daily Oral Exposures to Isopropanol in Rats on Litter Parameters in
the Gestational and Postpartum Components of a One-Generation Reproductive Study"
Parameter
Exposure Group (mg/kg-d)
0
668/1,053
1,330/1,948
1,902/2,768
No. of infertile males
0
0
0
0
Length of gestation (days)b
22.1 ±0.36
22.2 ±0.49
22.1 ±0.24
22.3 ±0.45
No. of females with litters on PND 1
15
20
17
16
No. of pups/litter on PND 1
7.9
9.5
8.3
6.1
Total no. pup survival (%)
84
89.4
89.4
71.4
Pup survival/litter (%)
87.5
85.3
86
58.6
Pup B W on PND 1 (g)b
5.9 ± 1.54
5.6 ± 1.09
5.3 ± 1.10
5.7 ±0.81
Pup B W on PND 4 (g)b
8.9 ±2.07
8.6 ± 1.90
8.3 ± 1.50
8.1 ±0.92
Pup B W on PND 7 (g)b
13.0 ±2.86
12.4 ±2.35
12.2 ±2.04
10.5 ± 1.23** (|12%)
Pup BW on PND 14 (g)b
27.6 ±5.71
25.7 ±5.04
26.3 ±3.74
23.7 ±2.71
Pup BW on PND 21 (g)b
47.4 ±7.22
44.2 ±8.08
44.0 ±5.38
38.3 ±5.06** (119%)
Pup BWG on PND 1-21 (g)b
42.3 ±6.35
38.5 ±7.14
38.6 ±4.68
32.7 ±5.14*** (|23%)
aData were obtained from Table 5 on page 471 in Faberet al. (20081.
bReported as mean ± SD.
**p < 0.01; ANOVA.
***p < 0.001; ANOVA.
74
Isopropanol
-------
FINAL
9-16-2014
Table B-9. Effects of Daily Oral Exposures to Isopropanol in Rats in the Gestational and
Postpartum Components of a One-Generation Reproductive Study"
Parameter
Exposure Group (mg/kg-d)
0
668
1,330
1,902
All litters («)''
9
9
7
8
Corpora lutea per dam0
13.2 ± 1.09
13.8 ±2.05
12.7 ±0.76
13.3 ± 1.04
Implantation sites per litter0
13.1 ±0.78
13.3 ±2.29
13.0 ±0.82
12.4 ± 1.19
Preimplantation losses0
0.1 ±0.33
0.7 ±0.73
0.1 ±0.38
1.0 ± 1.31*
Live fetuses0
12.1 ± 1.62
12.4 ± 1.88
12.0 ±0.82
12.1 ± 1.55
Early resorptions0
0.9 ± 1.27
0.8 ± 1.39
1.0 ±0.82
0.4 ±0.52
Late resorptions0
0.1 ±0.33
0.1 ±0.33
0
0
Postimplantation losses0
1.0 ± 1.22
0.9 ± 1.36
1.0 ±0.82
0.4 ±0.52
Mean % implantations
92.2
94.1
92.4
96.8
Litter weight (g)°
25.3 ±3.34
26.7 ±3.78
26.5 ±7.13
22.9 ±2.04
Fetal body weight (g)°
2.09 ±0.135
2.15 ±0.095
2.19 ±0.461
1.90 ±0.133
aData were obtained from Table 6 on page 471 in Faberet al. (20081.
bNumber of females with litters on GD 20.
°Reported as mean ± SD.
*p < 0.05; ANOVA.
75
Isopropanol
-------
FINAL
9-16-2014
Table B-10. Organ Weights in Rats After Continuous Exposure to Isopropanol in Drinking
Water for Two-Generationsa'b
Exposure Group (mg/kg-d)
0
347
625
1,030
F0 Males
No. in Group
10
10
10
10
Terminal BW (g)
454.5 ±45.80
459.9 ±34.35
458.5 ±52.58
426.4 ±28.51
Liver (g)
11.64 ± 1.317
11 49 ± 1.137
11.90 ± 1.774
12.20 ± 1.046
(g/lOOgBW)
2.57 ±0.276
2.50 ±0.137
2.59 ±0.143
2.86 ±0.171** (fll)
Spleen (g)
0.84 ±0.148
0.87 ±0.119
0.82 ±0.124
0.91 ±0.103
(g/lOOgBW)
0.19 ±0.031
0.19 ±0.032
0.18 ±0.013
0.21 ±0.019* (fll)
Kidney (g)
2.79 ±0.279
2.71 ±0.180
2.85 ±0.418
3.07 ± 0.187* (tlO)
(g/lOOgBW)
0.62 ±0.059
0.59 ±0.045
0.62 ± 0.060
0.72 ±0.030*** (t 16)
Exposure Group (mg/kg-d)
0
668/1,053c
1,330/1,948c
1,902/2,768c
F0 Females
No. in Group
15
20
17
16
Terminal BW (g)
234.1 ± 11.73
239.8 ± 10.70
237.6 ± 14.50
234.4 ±20.90
Liver (g)
6.74 ±0.712
6.77 ±0.521
7.35 ±0.928
8.00 ± 1.327***
(t 19%)
(g/100 g BW)
2.88 ±0.273
2.83 ±0.249
3.10 ±0.345
3.29 ±0.543**
(t 14%)
Spleen (g)
0.53 ±0.071
0.55 ±0.056
0.58 ±0.096
0.52 ±0.078
(g/100 gBW)
0.23 ±0.027
0.23 ± 0.024
0.24 ±0.035
0.21 ±0.023
Kidney (g)
1.54 ±0.085
1.53 ±0.092
1.59 ±0.161
1.66 ± 0.153* (t8)
(g/100 gBW)
0.66 ±0.031
0.64 ±0.035
0.67 ± 0.062
0.68 ±0.055
F1 Males
No. in Group
12
17
13
9
Terminal BW (g)
173.3 ±34.91
179.8 ±24.46
178.5 ±31.44
167.0 ± 22.74
Liver (g)
6.68 ± 1.255
7.31 ± 1.022
7.38 ± 1.446
7.28 ±0.872
(g/100 gBW)
3.87 ±0.260
4.07 ±0.182* (|5)
4.13 ± 0.332** (|7)
4.37 ±0.116*** (t 13)
Spleen (g)
0.62 ±0.131
0.60 ± 0.067
0.63 ±0.118
0.57 ±0.107
(g/100 gBW)
0.36 ±0.041
0.34 ±0.052
0.36 ±0.068
0.34 ±0.039
Kidney (g)
1.51 ±0.251
1.55 ±0.186
1.50 ±0.214
1.54 ±0.223
(g/100 gBW)
0.88 ±0.066
0.86 ± 0.067
0.85 ± 0.065
0.92 ± 0.059 (t5)
F1 Females
No. in Group
12
18
14
9
Terminal BW (g)
128.4 ± 16.50
128.3 ± 14.45
132.1 ± 17.57
124.4 ± 15.91
Liver (g)
4.84 ±0.716
5.15 ±0.621
5.23 ± 0.667
5.40 ±0.707
(g/100 gBW)
3.73 ±0.243
4.02 ± 0.252** (|8)
4.00 ±0.325* (|7)
4.48 ±0.200*** (t20)
76
Isopropanol
-------
FINAL
9-16-2014
Table B-10. Organ Weights in Rats After Continuous Exposure to Isopropanol in Drinking
Water for Two-Generationsa'b
Exposure Group (mg/kg-d)
0
347
625
1,030
Spleen (g)
0.47 ±0.071
0.47 ±0.061
0.46 ± 0.073
0.45 ±0.094
(g/lOOgBW)
0.37 ±0.039
0.37 ±0.041
0.35 ±0.041
0.36 ±0.050
Kidney (g)
1.15 ± 0.130
1.16 ±0.170
1.17 ± 0.117
1.14 ±0.124
(g/lOOgBW)
0.90 ±0.045
0.90 ± 0.060
0.90 ± 0.074
0.92 ±0.050
aData were obtained from Table 7 on page 472 in Faberet al. (20081.
bDirection of percentage difference from control is included in parentheses.
°Gestation/lactation doses.
Values are means ± SD.
*p < 0.05.
**p < 0.01.
***p < 0.001.
77
Isopropanol
-------
FINAL
9-16-2014
Table B-ll. Mean Absolute Organ Weights in Rats Exposed Daily to Isopropanol by
Gavage Prior to and During Mating, and During Gestation and Lactation"
Exposure Group (mg/kg-d)
0
100
500
1,000
F0 Males
Body weight (g)
603.8 ±45.9
583.5 ±51.9
618.6 ±42.1
612 ±59.1
Organ weight (g)
Liver
23.0 ±3.1
21.9 ±3.0
24.0 ±2.8
25.6 ±2.8** (|ll)b
Kidney
4.7 ±0.6
4.5 ±0.4
4.8 ±0.5
5.0 ±0.5
Organ weight/Body-weight ratio (%)
Liver (% increase)
3.8 ±0.4
3.7 ±0.3
3.9 ±0.3
4.2 ±0.3** (|10)
Kidney
0.79 ±0.11
0.76 ±0.05
0.78 ±0.06
0.83 ±0.07
F1 Males
Body weight (g)
661.2 ±63.7
678.2 ± 62.7
683.1 ±66.2
630.2 ±60.8
Organ weight (g)
Liver
24.1 ±3.2
25.2 ±3.5
27.2 ±3.8*
25.9 ±3.9
Kidney
4.6 ±0.5
4.5 ±0.4
4.8 ±0.5
4.7 ±0.6
Organ weight/Body-weight ratio (%)
Liver (% increase)
3.6 ±0.3
3.7 ±0.3
4.0 ±0.3** (fll)
4.1 ±0.4** (f 14)
Kidney (% increase)
0.7 ±0.07
0.66 ± 0.06
0.70 ±0.06
0.75 ± 0.08** (|7)
F0 Females
Body weight (g)
331.6 ± 38.4
330.2 ±30.2
335.2 ± 31.9
328.3 ±29.4
Organ weight (g)
Liver
13.2 ±2.0
13.3 ± 1.7
14.2 ±2.0
14.4 ± 1.7
Kidney
2.6 ±0.3
2.6 ±0.3
2.7 ±0.2
2.7 ±0.3
Organ weight/Body-weight ratio (%)
Liver (% increase)
4.0 ±0.4
4.0 ±0.3
4.2 ±0.4* (|5)
4.4 ±0.4** (t 10)
Kidney (% increase)
0.77 ±0.07
0.79 ±0.06
0.80 ±0.06
0.82 ±0.06* (|6)
F1 Females
Body weight (g)
366.8 ±34.8
369.8 ±36.9
355.1 ±46.2
353.5 ±31.9
Organ weight (g)
Liver
14.0 ± 1.7
14.3 ± 1.6
14.5 ±2.6
16.0 ± 1.9** (f 14)
Kidney
2.7 ±0.3
2.7 ±0.3
2.7 ±0.4
2.8 ±0.2
Organ weight/Body-weight ratio (%)
Liver (% increase)
3.8 ±0.3
3.9 ± 0.3
4.1 ± 0.4* (|8)
4.5 ±0.6** (f 18)
Kidney (% increase)
0.74 ±0.06
0.74 ± 0.07
0.77 ±0.09
0.8 ±0.08* (|8)
aData were obtained from Tables 1 and 2 on page 120 in Bevanetal. (19951.
bDirection of percentage difference from control is included in parentheses.
Values are means ± SD.
*p < 0.05 and **p < 0.01.
78
Isopropanol
-------
FINAL
9-16-2014
Table B-12. Summary of Reproductive Data from Parental Rats Exposed Daily to
Isopropanol by Gavage"
Exposure group (mg/kg-d)
0
100
500
1,000
F0
Male mating index (%)b
86.7
90.0
93.1
96.7
Male fertility index (%)°
80.0
83.3
82.8
70.0
Female fertility index (%)d
89.7
90.0
93.3
96.7
Female fecundity index (%)e
88.5
88.9
85.7
72.4
Gestational index (%)f
100
100
100
100
Mean gestational length (days)
22.5
22.5
22.4
22.6
Mean litter size
12.4
13.3
14.2
14.4
Mean live/litter
12.2
13.2
13.7
13.8
Mean dead/litter
0.2
0.1
0.5
0.6
F1
Male mating index (%)b
93.3
96.4
93.1
73.1*
Male fertility index (%)°
80.0
82.1
72.4
61.5
Female fertility index (%)d
93.3
96.7
93.1
82.6
Female fecundity index (%)e
82.1
79.3
77.8
78.9
Gestational index (%)f
100
95.8
100
100
Mean gestational length (days)
22.7
22.6
22.7
22.6
Mean litter size
13.2
14.0
14.1
14.4
Mean live/litter
13.0
13.7
13.7
14.0
Mean dead/litter
0.2
0.4
0.4
0.4
aData were obtained from Table 3 on page 121 in Bevanetal. (19951.
b(No. of confirmed mated males ^ no. of males used for mating) / 100.
°(No. of males impregnating females ^ no. of males used for mating) x 100.
d(No. of confirmed mated females no. of females used in mating) x 100.
e(No. of females pregnant, excluding nonconfirmed mated females no. of females confirmed mated) x 100.
f(No. of females with live litters ^ no. of females pregnant) x 100.
*p < 0.05.
79
Isopropanol
-------
FINAL
9-16-2014
Table B-13. Summary of Offspring Survival Data from Parental Rats Exposed Daily
to Isopropanol by Gavage"
Exposure Group (mg/kg-d)
0
100
500
1,000
F1
Live birth index (%)b
98.3
99.4
96.3
95.7*
Day 1 survival index (%)°
98.6
97.6
98.0
84.5**
Day 4 survival index (%)d
99.7
98.4
96.7**
91.0**
Day 7 survival index (%)e
100
100
99.5
99.2
Day 14 survival index (%)f
100
100
99.5
100
Day 21 survival index (%)g
100
99.5
100
99.2
Lactation index11
99.4
99.5
99.0
92.2
F2
Live birth index (%)b
98.4
97.9
97.0
97.0
Day 1 survival index (%)°
99.4
98.8
94.8**
94.2**
Day 4 survival index (%)d
99.0
99.1
97.1
96.2*
Day 7 survival index (%)e
100
99.4
96.3*
91.0**
Day 14 survival index (%)f
100
98.9
98.1
100
Day 21 survival index (%)g
100
99.4
100
100
Lactation index11
100
97.8
94 4**
91.0**
aData were obtained from Table 4 on page 121 in Bevanetal. (19951.
b(No. of live pups at birth ^ no. of pups born) x 100.
°(No. of live pups at Day 1 ^ no. of live pups at birth) x 100.
d[No. of live pups at Day 4(precull) ^ no. of live pups at Day 1] x 100.
e[No. of live pups at Day 7 no. of live pups at Day 4(postcull)] x 100.
f(No. of live pups at Day 14 no. of live pups at Day 7) x 100.
g(No. of live pups at Day 21 ^ no. of live pups at Day 14) x 100.
h[No. of live pups at Day 21 ^ no. of live pups at Day 4(postcull)] x 100.
*p < 0.05.
**p < 0.01.
80
Isopropanol
-------
FINAL
9-16-2014
Table B-14. Summary of F1 and F2 Offspring Body Weights from Parental Rats Exposed
Daily to Isopropanol by Gavage"
Postnatal Day
Exposure Group (mg/kg-d)
0
100
500
1,000
F1 Males
0
6.61 ±0.79
6.68 ±0.75
6.46 ± 0.70
6.27 ± 0.77* (|5)b
1
7.00 ±0.79
7.19 ±0.87
6.77 ±0.91
6.51 ± 0.86* (4,7)
4
9.47 ± 1.56
9.94 ± 1.54
9.30 ± 1.62
8.94 ± 1.56
7
15.09 ±2.67
15.96 ±2.30
14.21 ±2.74
14.31 ±2.59
14
30.71 ±4.18
32.65 ±3.69
30.46 ±5.22
30.21 ±4.71
21
48.01 ±7.63
52.94 ±6.59*
48.24 ±7.83
49.19 ±6.54
F1 Females
0
6.22 ± 0.64
6.37 ±0.72
6.25 ± 0.70
5.98 ±0.71
1
6.57 ±0.69
6.84 ±0.80
6.59 ±0.93
6.25 ±0.90
4
9.05 ± 1.41
9.54 ± 1.44
9.09 ± 1.64
8.35 ± 1.79
7
14.21 ±2.30
15.34 ±2.33
13.62 ±2.75
12.97 ±2.66
14
29.32 ±3.89
31.89 ±4.07*
29.77 ±4.79
28.35 ±4.78
21
45.56 ±6.59
50.79 ±6.06**
46.94 ±7.03
45.85 ±6.93
F2 Males
0
6.66 ± 0.66
6.75 ±0.71
6.58 ±0.76
6.33 ± 0.77* (|5)
1
7.20 ±0.81
7.21 ±0.81
7.03 ± 0.94
6.45 ±0.97** (|10)
4
10.21 ± 1.68
10.24 ± 1.49
9.72 ± 1.65
9.34 ± 1.94* (49)
7
16.34 ±2.75
16.14 ±2.96
15.72 ±2.69
15.39 ±2.97
14
32.74 ±3.62
32.66 ±4.48
32.54 ±3.80
31.11 ± 4.97
21
50.25 ±6.74
50.40 ±7.41
50.74 ±6.51
47.71 ±6.15
F2 Females
0
6.31 ±0.69
6.35 ±0.66
6.31 ±0.62
5.79 ±0.64** (48)
1
6.87 ±0.89
6.84 ±0.81
6.67 ±0.83
6.07 ±0.79** (412)
4
9.70 ± 1.67
9.73 ± 1.43
9.27 ± 1.75
8.50 ± 1.63** (412)
7
15.16 ± 3.19
15.56 ±2.87
14.96 ±3.13
14.07 ±2.79
14
30.45 ±5.30
31.59 ±4.49
31.14 ± 4.13
28.97 ±4.81
21
47.17 ±6.92
48.94 ±7.06
48.59 ±6.82
45.15 ±7.21
aData were obtained from Tables 5 and 6 on page 122 in Bevanetal. (19951.
bDirection of percentage difference from control is included in parentheses.
Values are means ± SD.
*p < 0.05 and **p < 0.01.
81
Isopropanol
-------
FINAL
9-16-2014
Table B-15. Summary of Motor Activity Data (Mean Cumulative Test Session Counts ± SD)
in Rats Exposed to Isopropanol by Vapor Inhalation9
Time
Group 1 (13-Week Exposure)
Group 2 (9-Week Exposure)
Human Equivalent Concentration (HEC, mg/m3)
0
2,199
0
2,199
Pre-exposure
933.4 ±480.6
965.0 ±364.57
679.0 ± 175.0
758.3 ±201.12
Week 4-1 Day Postexposure
956.1 ±229.21
1,294.5 ±420.25*
1,034.5 ±354.32
1,461.5 ± 589.3*
Week 7-1 Day Postexposure
1,121.0 ±445.09
1,710.7 ±733.58*
1,028.2 ±237.0
1,838.9 ±805.45*
Week 9-1 Day Postexposure
783.3 ±221.72
1,913.6 ±693.46**
1,049.6 ±281.44
1,852.7 ±613.0**
Week 9-2 Day Postexposure
NDb
ND
968.4 ± 342.72
1,180.6 ±661.17
Week 10-4 Day Postexposure
ND
ND
733.8 ±261.3
903.5 ± 533.4
Week 10-7 Day Postexposure
ND
ND
678.4 ± 264.04
734.5 ±309
Week 11-1 Day Postexposure
809.5 ±371.43
1,646.2 ± 1,024.69**
ND
ND
Week 13-1 Day Postexposure
934.9 ±328.52
2,020.8 ±830.73**
ND
ND
Week 13-2 Day Postexposure
685.9 ±261.93
1,226.7 ±514.79**
ND
ND
Week 14-4 Day Postexposure
826.9 ±267.34
1,401.5 ±451.69**
ND
ND
Week 14-7 Day Postexposure
818.5 ±215.52
1,128.9 ±478.5*
ND
ND
Week 15-14 Day Postexposure
1,320.9 ±558.63
1,393.6 ±442.13
ND
ND
Week 16-21 Day Postexposure
758.1 ±425.82
963.3 ±380.47
ND
ND
Week 17-28 Day Postexposure
955.2 ± 355.22
1,431.3 ±718.77*
ND
ND
Week 18-35 Day Postexposure
1,266.9 ±455.41
1,496.6 ±635.5
ND
ND
Week 19-42 Day Postexposure
1,438.8 ±626.03
1,510.9 ±648.44
ND
ND
aData were obtained from Table 1 on pages 98-99 in Burleigh-Flaver et al. (19981.
bND—no value determined; no animals tested from this block at this time.
n = 15/concentration group.
Values are mean ± SD.
*p < 0.05.
**p < 0.01.
82
Isopropanol
-------
FINAL
9-16-2014
Table B-16. Cesarean Section Observations on GD 20 in Rats Exposed to Isopropanol by
Vapor Inhalation from GDs l-19a
Parameter
Human Equivalent Concentration (HEC, mg/m3)
0
2,516
5,048
7,185
No. pregnant per no. bred
15/15
14/15
13/13
9/15
Mean no. of corpora lutea per dam
15.9
15.6
15.6
14.9
Mean no. of implants per dam
14.9
15.5
14.8
13.1* (412)
Implants resorbed per litter (%)
6
4
7
59* (|883)
Implants alive per litter (%)
94
96
93
41* (456)
Mean fetal weights ± SD (g)
Female
3.12 ±0.29
3.00 ± 0.38* (|4)b
2.63 ± 0.25* (|16)
1.88 ±0.45* (440)
Male
3.27 ±0.27
3.13 ± 0.36* (|4)
2.82 ±0.30* (|14)
1.89 ±0.49* (442)
aData were obtained from Table 3 on page 251 in Nelson etal. (19881.
bDirection of percentage difference from control is included in parentheses.
*p < 0.05; Kruskal-Wallis test for corpora lutea comparisons and ANOVA for fetal data.
83
Isopropanol
-------
FINAL
9-16-2014
Table B-17. Mean (SD) Results of Urinalysis and Urine Chemistry Evaluations in Rats
Exposed to Isopropanol by Vapor Inhalation for up to 24 Months"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
13 Months
Osmolality (mOsm/kg)
Male
2,332 ±217.5
2,113 ±318.2
2,157 ±300.7
1,574 ± 182.8**
Female
2,808 ± 280.5
3,036 ±436.7
2,739 ±397.1
2,512 ±258.5
Total Protein (g/L)
Male
11.426 ±3.6650
11.534 ±4.0704
12.768 ±3.5047
15.926 ±4.0636*
Female
8.526 ±4.6510
7.438 ± 3.8735
10.548 ±5.6097
6.424 ± 1.3920
Total Volume (mL)
Male
8.3 ±2.53
7.3 ±2.59
8.0 ±2.05
9.9 ±2.07
Female
4.9 ± 1.54
5.7 ±2.08
6.4 ± 1.98
7.3 ± 1.77**
Glucose (g/L)
Male
1.00 ±0.254
1.09 ±0.338
0.93 ±0.392
0.82 ±0.183
Female
0.71 ±0.145
0.70 ±0.136
0.64 ±0.126
0.54 ±0.088**
17 Months
Osmolality (mOsm/kg)
Male
1,225 ±401.7
1,491 ± 355.7
942 ± 346.0
605 ± 154.4**
Female
1,973 ± 322.8
1,954 ± 367.8
1,841 ±413.8
1,254 ± 440.6**
Total Protein (g/L)
Male
11.821 ±4.7889
13.243 ±4.0401
17.306 ±8.1660
19.382 ±3.8714**
Female
8.333 ± 3.0904
6.795 ±2.2485
12.652 ±7.5233
16.561 ±7.1626**
Total Volume (mL)
Male
8.7 ±2.87
5.9 ± 1.96
11.9 ±5.68
16.5 ±4.47**
Female
6.3 ± 1.78
5.0 ± 1.00
7.3 ±3.32
11.6 ± 6.11*
Glucose (g/L)
Male
0.43 ± 0.240
0.47 ± 0.227
0.29 ±0.087
0.21 ±0.054*
Female
0.54 ±0.084
0.54 ±0.127
0.52 ±0.145
0.41 ±0.139
24 Months
Osmolality (mOsm/kg)
Male
842 ±405.1
801 ±314.9
572 ± 128.3
b
Female
1,108 ± 590.1
1,054 ± 328.4
934 ± 347.0
537 ±256.3*
Total Protein (g/L)
Male
21.201 ±6.4667
19.344 ±3.3613
25.088 ±6.1684
b
Female
17.020 ± 7.9967
19.931 ±5.6631
20.213 ±6.9797
19.507 ±7.1804
84
Isopropanol
-------
FINAL
9-16-2014
Table B-17. Mean (SD) Results of Urinalysis and Urine Chemistry Evaluations in Rats
Exposed to Isopropanol by Vapor Inhalation for up to 24 Months"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Total Volume (mL)
Male
11.7 ±4.79
13.8 ± 6.16
16.3 ±7.74
b
Female
11.0 ±5.66
12.1 ±4.05
14.8 ±5.14
23.3 ±6.92**
Glucose (g/L)
Male
0.39 ±0.194
0.36 ±0.122
0.28 ±0.087
b
Female
0.51 ±0.256
0.52 ±0.095
0.47 ±0.116
0.33 ±0.146*
aData were obtained from Table 1 on page 101 in Burleigh-Flaver et al. (19971.
bThere were no surviving animals at this time point.
Significantly different from control.
*p < 0.05.
**p < 0.01.
85
Isopropanol
-------
FINAL
9-16-2014
Table B-18. Mean (±SD) Results of Selected Organ Weights as a Percentage of Final Body
Weight in Rats Exposed to Isopropanol by Vapor Inhalation for up to 104 Weeks"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Interim Euthanasia (Week 73)
Kidney
Male
0.742 ±0.1202
0.706 ± 0.0449
0.722 ± 0.0473
0.821 ±0.0430
Female
0.779 ± 0.0540
0.767 ± 0.0676
0.757 ±0.0544
0.800 ±0.0871
Liver
Male
3.455 ±0.6166
3.279 ±0.1550
3.693 ±0.5405
4.283 ± 0.6276** (|24)
Female
3.419 ±0.3480
3.275 ±0.2292
3.311 ±0.2653
3.447 ±0.3295
Testes
Male
0.646 ±0.1394
0.702 ± 0.0773
0.817 ±0.1719*
0.993 ±0.1693**(|53)
Brain
Male
0.460 ± 0.0549
0.443 ± 0.0273
0.442 ± 0.0287
0.427 ±0.0151
Female
0.645 ±0.0368
0.662 ± 0.0584
0.630 ±0.0307
0.650 ±0.0594
Lung
Male
0.442 ± 0.2906
0.374 ±0.0578
0.404 ±0.1261
0.384 ±0.0589
Female
0.389 ±0.0296
0.409 ± 0.0246
0.397 ±0.0326
0.426 ±0.0539
Terminal Euthanasia (Week 104)
Kidney
Male
1.017 ±0.3057
0.914 ±0.2244
1.140 ±0.2953
b
Female
1.056 ±0.3424
0.886 ±0.1812*
0.875 ±0.1923*
1.214 ±0.3391
Liver
Male
4.693 ±0.9872
4.603 ±0.7731
5.855 ± 1.0923*
b
Female
4.363 ±0.8208
4.202 ±0.8523
4.342 ±0.7325
5.394 ±0.5415** (|24)
Testes
Male
1.174 ±0.5502
1.457 ±0.6831
1.407 ±0.5896
b
Brain
Male
0.560 ±0.1023
0.525 ±0.0498
0.554 ±0.0984
b
Female
0.701 ±0.1072
0.638 ±0.0942**
0.604 ± 0.0742**
0.647 ± 0.0942*
Lung
Male
0.669 ± 0.2875
0.625 ±0.3170
0.865 ± 0.4844
b
Female
0.536 ±0.2070
0.458 ±0.0938
0.492 ±0.2471
0.573 ±0.2416
aData were obtained from Table 3 on page 103 in Burleigh-Flaver et al. (19971.
bThere were no surviving animals at this time point.
Significantly different from control.
*p < 0.05.
**p < 0.01.
86
Isopropanol
-------
FINAL
9-16-2014
Table B-19. Microscopic Findings in Kidneys of Male Rats Exposed
to Isopropanol by Vapor Inhalation9
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Number of Animals
75
75
75
75
Mineralization
13
11
24
46
Minimal
4
1
2
2
Mild
1
2
3
5
Moderate
4
5
8
21
Marked
4
3
11
18
Glomeruloscerosis
70
68
73
73
Minimal
1
8
6
0
Mild
38
30
22
17
Moderate
18
18
19
10
Marked
12
12
26
43
Severe
1
0
0
3
Interstitial nephritis
57
66
60
70
Minimal
4
9
5
0
Mild
44
41
22
36
Moderate
9
16
33
33
Marked
0
0
0
1
Interstitial fibrosis
48
60
65
67
Minimal
2
10
3
2
Mild
31
33
30
21
Moderate
15
17
27
42
Marked
0
0
5
2
Hydronephrosis
22
23
28
50
Minimal
0
0
1
0
Mild
22
23
27
46
Moderate
0
0
0
4
Transitional cell hyperplasia
12
14
30
39
Minimal
4
4
6
6
Mild
7
9
21
31
Moderate
1
1
2
2
Marked
0
0
1
0
87
Isopropanol
-------
FINAL
9-16-2014
Table B-19. Microscopic Findings in Kidneys of Male Rats Exposed
to Isopropanol by Vapor Inhalation9
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Tubular proteinosis
75
73
75
74
Minimal
1
0
1
0
Mild
24
25
18
10
Moderate
28
25
20
13
Marked
16
16
19
16
Severe
6
7
17
35
Tubular dilation
14
5
27
31
Mild
13
3
13
20
Moderate
0
2
14
11
Marked
1
0
0
0
aData were obtained from Table 5 on page 107 in Burleigh-Flaver et al. (19971.
88
Isopropanol
-------
FINAL
9-16-2014
Table B-20. Microscopic Findings in Kidneys of Female Rats Exposed
to Isopropanol by Vapor Inhalation9
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Number of Animals
75
75
75
75
Mineralization
14
12
21
20
Minimal
7
8
9
1
Mild
2
0
1
2
Moderate
1
2
4
10
Marked
4
2
7
7
Glomeruloscerosis
65
66
64
70
Minimal
8
14
8
3
Mild
34
36
28
21
Moderate
13
12
17
22
Marked
10
4
11
24
Interstitial nephritis
44
50
59
58
Minimal
11
8
15
2
Mild
28
35
40
54
Moderate
5
7
4
2
Interstitial fibrosis
42
40
51
53
Minimal
8
11
10
3
Mild
22
19
26
20
Moderate
12
10
15
30
Hydronephrosis
10
11
14
21
Mild
9
11
13
19
Moderate
1
0
1
2
Transitional cell hyperplasia
4
2
2
8
Minimal
0
1
0
6
Mild
4
1
2
2
Tubular proteinosis
73
73
74
75
Minimal
8
2
6
4
Mild
26
31
18
14
Moderate
25
28
27
23
Marked
12
9
15
23
Severe
2
3
8
11
Tubular dilation
5
7
6
24
Mild
2
5
5
16
Moderate
3
2
1
8
aData were obtained from Table 6 on page 108 in Burleigh-Flaver et al. (19971.
89
Isopropanol
-------
FINAL
9-16-2014
Table B-21. Mean (±SD) Results of Selected Organ Weights as a Percentage of
Final Body Weight in Mice Exposed
to Isopropanol by Vapor Inhalation for up to 78 Weeks"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Interim Euthanasia (Week 54)
Kidney
Male
2.306 ±0.3670
2.192 ±0.2249
2.307 ±0.3662
2.304 ±0.3178
Female
1.464 ±0.00882
1.582 ±0.2263
1.622 ±0.2165
1.444 ±0.1497
Liver
Male
5.732 ± 0.5354
5.708 ±0.4639
5.788 ±0.6522
6.547 ± 0.8840** (|14)
Female
5.472 ± 0.2849
5.643 ± 0.4365
5.811 ±0.4400
5.859 ±0.9078
Testes
Male
0.620 ±0.1319
0.559 ±0.1489
0.557 ±0.0704
0.484 ± 0.0843
Brain
Male
1.380 ±0.1488
1.333 ±0.1474
1.268 ±0.0973
1.267 ±0.1357
Female
1.491 ±0.1011
1.591 ±0.1230
1.490 ±0.1450
1.360 ±0.1350*
Lung
Male
0.788 ±0.3499
0.671 ±0.0545
0.643 ±0.0817
0.640 ± 0.0770
Female
0.686 ± 0.0526
0.695 ±0.0351
0.713 ±0.0714
0.667 ±0.0558
Terminal Euthanasia (Week 78)
Kidney
Male
2.150 ±0.4560
2.243 ±0.4188
2.149 ±0.3060
2.057 ±0.2183
Female
1.577 ±0.2191
1.548 ±0.1804
1.558 ±0.2147
1.573 ±0.1945
Liver
Male
5.823 ± 1.2043
5.726 ±0.9857
6.203 ± 1.4794
6.173 ± 1.6437
Female
5.822 ±0.7635
5.903 ±0.7201
6.139 ±0.8526
6.642 ± 0.6800** (|14)
Testes
Male
0.566 ± 0.0896
0.479 ± 0.1335**
0.495 ±0.0956*
0.496 ±0.1050**
Brain
Male
1.387 ±0.1256
1.366 ±0.2047
1.323 ±0.1695
1.240 ±0.1071**
Female
1.575 ±0.1724
1.540 ±0.1392
1.518 ±0.1400
1.438 ±0.1348**
Lung
Male
0.782 ±0.2325
0.749 ±0.2014
0.758 ±0.2289
0.760 ±0.1672
Female
0.809 ±0.1548
0.781 ±0.1165
0.785 ±0.1447
0.828 ±0.1427
Recovery Euthanasia (Week 78—only exposed through Week 54)
Kidney
Male
2.062 ±0.2014
1.923 ±0.1822
2.067 ±0.3037
2.030 ±0.3060
Female
1.428 ±0.2014
1.636 ±0.2477
1.644 ±0.2786
1.498 ±0.2286
90
Isopropanol
-------
FINAL
9-16-2014
Table B-21. Mean (±SD) Results of Selected Organ Weights as a Percentage of
Final Body Weight in Mice Exposed
to Isopropanol by Vapor Inhalation for up to 78 Weeks"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Liver
Male
4.828 ±0.3637
5.333 ±0.4389* (|10)
5.611 ±0.8950* (f 16)
6.319 ± 1.2627* (|30)
Female
5.999 ±0.5685
6.454 ±0.4329
8.735 ± 5.2223
6.418 ± 1.7143
Testes
Male
0.490 ± 0.0854
0.410 ±0.1531
0.408 ±0.1069
0.459 ±0.0416
Brain
Male
1.240 ±0.1308
1.213 ±0.0993
1.195 ± 0.1106
1.152 ±0.0660
Female
1.390 ±0.1362
1.432 ±0.0751
1.414 ±0.1921
1.316 ±0.1375
Lung
Male
0.662 ± 0.0667
0.679 ±0.0791
0.750 ±0.1732
0.683 ±0.0915
Female
0.762 ± 0.0802
0.933 ± 0.2263
0.764 ± 0.0686
0.891 ±0.2105
aData were obtained from Table 2 on page 102 in Burleigh-Flaver et al. (19971.
Significantly different from control.
*p < 0.05.
**p < 0.01.
91
Isopropanol
-------
FINAL
9-16-2014
Table B-22. Mean (±SD) Results of Selected Absolute Organ Weights in Mice Exposed
to Isopropanol by Vapor Inhalation for up to 78 Weeks"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Interim Euthanasia (Week 54)
Body
Male
36.8 ±4.98
38.0 ±2.78
40.7 ±4.47 (|11%)
41.3 ± 5.18(112%)
Female
35.0 ±2.09
33.9 ±2.27
35.8 ± 3.13
38.1 ± 3.19*
Kidney
Male
0.843 ±0.1395
0.832 ±0.0841
0.939 ±0.1784 (|11%)
0.948 ±0.1625 (|12%)
Female
0.513 ±0.0473
0.535 ±0.0784
0.579 ±0.0842 (|13%)
0.550 ±0.0674
Liver
Male
2.098 ±0.2517
2.166 ±0.1785
2.361 ±0.4068 (|13%)
2.691 ±0.4456** (|28%)
Female
1.916 ±0.1401
1.912 ±0.1742
2.082 ± 0.2622
2.234 ±0.4123* (|17%)
Testes
Male
0.225 ± 0.0404
0.214 ±0.0621
0.226 ±0.0309
0.198 ±0.0322
Brain
Male
0.502 ±0.0254
0.505 ± 0.0467
0.513 ±0.0268
0.517 ±0.0131
Female
0.521 ±0.0310
0.538 ±0.0346
0.530 ±0.0277
0.516 ±0.0471
Lung
Male
0.282 ±0.0971
0.255 ±0.0217
0.261 ±0.0394
0.262 ± 0.0246
Female
0.240 ±0.0130
0.236 ± 0.0220
0.254 ±0.0233
0.254 ±0.022
Terminal Euthanasia (Week 78)
Body
Male
37.2 ±3.72
38.6 ±4.03
40.1 ±3.73**
41.0 ± 3.53** (|10%)
Female
34.3 ±3.46
35.2 ±2.66
34.6 ±3.50
35.4 ±3.45
Kidney
Male
0.797 ±0.1631
0.868 ± 0.2045
0.858 ±0.1139
0.844 ±0.1166
Female
0.540 ±0.0931
0.544 ±0.0693
0.538 ±0.0740
0.557 ±0.0896
Liver
Male
2.158 ±0.4356
2.215 ±0.4815
2.497 ±0.6615* (|14%)
2.540 ±0.7349** (|18%)
Female
1.997 ±0.3508
2.080 ±0.3335
2.136 ±0.4264
2.359 ±0.3776** (|18%)
Testes
Male
0.209 ±0.0317
0.182 ±0.0460**
0.198 ±0.0403
0.202 ±0.0388
Brain
Male
0.512 ±0.0284
0.521 ±0.0458
0.527 ± 0.0445
0.506 ±0.0283
Female
0.535 ±0.0308
0.539 ±0.0287
0.522 ±0.0311
0.506 ±0.0272**
92
Isopropanol
-------
FINAL
9-16-2014
Table B-22. Mean (±SD) Results of Selected Absolute Organ Weights in Mice Exposed
to Isopropanol by Vapor Inhalation for up to 78 Weeks"
Human Equivalent Concentration (HEC, mg/m3)
0
221
1,101
2,211
Lung
Male
0.289 ±0.0816
0.285 ±0.0601
0.301 ±0.0783
0.311 ±0.0709
Female
0.276 ± 0.0572
0.275 ± 0.0490
0.272 ± 0.0580
0.292 ±0.0461
Recovery Euthanasia (Week 78—only exposed through Week 54)
Body
Male
41.9 ± 3.18
43.2 ±3.52
43.3 ±2.63
44.8 ± 1.61
Female
39.6 ±3.67
37.0 ±2.30
36.7 ±5.09
40.1 ±3.56
Kidney
Male
0.865 ±0.1282
0.829 ±0.0851
0.892 ±0.1317
0.908 ±0.1317
Female
0.562 ± 0.0679
0.603 ± 0.025
0.596 ±0.0828
0.599 ±0.0965
Liver
Male
2.028 ± 0.2806
2.305 ±0.2732 (|14%)
2.414 ±0.3143* (f 19%)
2.822 ±0.5201** (|39%)
Female
2.367 ±0.2323
2.388 ±0.2338
3.201 ± 1.8984 (|35%)
2.588 ±0.8062
Testes
Male
0.203 ± 0.0273
0.174 ±0.0584
0.176 ±0.0448
0.205 ±0.0166
Brain
Male
0.516 ±0.0202
0.523 ±0.0383
0.516 ±0.0398
0.516 ±0.0314
Female
0.546 ±0.0257
0.529 ±0.0375
0.512 ±0.0147
0.524 ±0.3487
Lung
Male
0.277 ±0.0321
0.292 ±0.0253
0.323 ±0.0722
0.306 ±0.0415
Female
0.302 ±0.0435
0.342 ±0.0713
0.280 ± 0.0406
0.359 ±0.0965
aData were obtained from a technical report by the BushvRun (1994).
Significantly different from control.
*p < 0.05.
**p < 0.01.
93
Isopropanol
-------
FINAL
9-16-2014
Table B-23. Microscopic Findings in Selected Organs of Mice Exposed
to Isopropanol by Vapor Inhalation9
Number of Animals With Finding (%)
Animals Euthanized
Animals Found
Dead/Euthanized Moribund
Male
Human Equivalent
Concentration (HEC, mg/m3)
0
221
1,101
2,211
0
221
1,101
2,211
Number of animals:
35
32
29
31
20
23
26
24
Seminal
Vesicle
Ectasia
8 (23)
6(19)
7(24)
20 (65)**
7(35)
5(22)
11 (42)
15 (63)
Kidney
Tubular
proteinosis
8 (23)
16 (50)*
14 (48)*
14 (45)
7(35)
4(17)
7 (27)
9(38)
Tubular dilation
0(0)
5 (16)*
0(0)
1(3)
2(10)
2(9)
3(12)
0(0)
Female
Human Equivalent
Concentration (HEC, mg/m3)
0
221
1,101
2,211
0
221
1,101
2,211
Number of animals:
42
35
43
37
13
20
12
18
Kidney
Tubular
proteinosis
7(17)
16
(46)**
15 (35)
16 (43)*
3 (23)
4 (20)
5(42)
7(39)
Tubular dilation
1(2)
0(0)
3(7)
6(16)*
3 (23)
2(10)
2(17)
0(0)
Adrenal
Gland
Congestion
1(2)
0(0)
0(0)
8 (22)*
1(8)
0(0)
0(0)
4(22)
Stomach
Mucosal cell
hyperplasia
1(2)
0(0)
0(0)
9 (24)**
0(0)
1(5)
0(0)
0(0)
Spleen
Extramedullary
hematopoiesis
13 (31)
0(0)
2(5)
23 (62)**
7(54)
8 (40)
3(25)
9(50)
Hemosiderosis
7(17)
0(0)
1(2)
14 (38)*
0(0)
3(15)
0(0)
3(17)
aData were obtained from Table 4 on page 104 in Burleigh-Flaver et al. (19971.
Significantly different from control.
*p < 0.05.
**p < 0.01.
94
Isopropanol
-------
FINAL
9-16-2014
APPENDIX C. BMD OUTPUTS
MODELING PROCEDURE FOR CONTINUOUS DATA
The benchmark dose (BMD) modeling of continuous data was conducted with EPA's
Benchmark Dose Software (BMDS version 2.1.2) (U.S. EPA. 2010). For these data, all
continuous models available within the software were fit using a default BMR of 1 SD relative
risk. For changes in liver, body, and kidney weights, a BMR of 10% change relative to the
control mean was also used. For fetal and F1 pup effects, a BMR of 5% change relative to the
control mean was used. An adequate fit was judged based on the goodness-of-fit p-value
(p > 0.1), magnitude of the scaled residuals in the vicinity of the BMR, and visual inspection of
the model fit. In addition to these three criteria forjudging adequacy of model fit, a
determination was made as to whether the variance across dose groups was constant. If a
constant variance model was deemed appropriate based on the statistical test provided in BMDS
(i.e., Test 2), the final BMD results were estimated from a constant variance model. If the test
for homogeneity of variance was rejected {p < 0.1), the model was run again while modeling the
variance as a power function of the mean to account for this nonconstant variance. If this
nonconstant variance model did not adequately fit the data (i.e., Test 3; p-v alue < 0.1), the data
set was considered unsuitable for BMD modeling. Among all models providing adequate fit, the
lowest benchmark dose lower confidence limit (BMDL) was selected if the BMDLs estimated
from different models varied greater than 3-fold; otherwise, the BMDL from the model with the
lowest Akaike's Information Criteria (AIC) was selected as a potential POD from which to
derive a p-RfD.
MODELING PROCEDURE FOR DICHOTOMOUS DATA
The BMD modeling of dichotomous data was conducted with EPA's BMDS
(version 2.1.2). For these data, all of the dichotomous models (i.e., Gamma, Multistage,
Logistic, Log-logistic, Probit, Log-Probit, and Weibull models) available within the software
were fit using a default BMR of 10% extra risk based on the U.S. EPA's Benchmark Dose
Technical Guidance Document (U.S. EPA. 2012b). Adequacy of model fit was judged based on
the x2 goodness-of-fit p-v alue (p> 0.1), magnitude of scaled residuals in the vicinity of the
BMR, and visual inspection of the model fit. Among all models providing adequate fit, the
lowest BMDL was selected if the BMDLs estimated from different models varied greater than
3-fold; otherwise, the BMDL from the model with the lowest AIC was selected as a potential
POD from which to derive a p-RfD.
DECREASED FETAL BODY WEIGHT OF FEMALE RABBITS TREATED WITH
ISOPROPANOL FROM GESTATION DAY 6 to 18 (Tvl et al.. 1994)
All available continuous models in BMDS (version 2.1.2) (U.S. EPA. 2010) were fit to
the decreased fetal body weight data from female rabbits treated with isopropanol from GD 6 to
18 (Tvl et al.. 1994) (see Table B-4). For decreased fetal body weight, a BMR of a 5% change
relative to the control mean was used. The homogeneity variance (Test 2) p-v alue of less than
0.1 indicates that nonconstant variance is the appropriate variance model. As assessed by the
goodness-of-fit test and visual inspection, the Polynomial model provided the best fit model (see
Table C-l and Figure C-l). Estimated doses associated with 5% relative risk and the 95% lower
confidence limit on these doses (BMDos values and BMDLos values, respectively) were 284 and
120 mg/kg-day.
95
Isopropanol
-------
FINAL
9-16-2014
Table C-l. Model Predictions for Fetal Body Weight"
Model
BMD
BMDL
/j-value
Test 2b
/>-value
Test 3b
/>-value
Test 4b
AIC
Conclusion
Exponential (M2)
168
99.0
0.015
0.127
0.162
267
Exponential (M3)
279
116
0.015
0.127
0.146
268
Exponential (M4)
168
82.8
0.015
0.127
0.162
267
Exponential (M5)
242
124
0.015
0.127
NDr
269
Hill
242
124
0.015
0.172
0.135
267
Power
281
120
0.015
0.127
0.144
268
Polynomial
284
120
0.015
0.172
0.255
266
Lowest AIC
Linear
172
106
0.015
0.172
0.130
268
aTvl etal. (19941.
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMD = benchmark dose; BMDL = lower confidence limit (95%) on the
benchmark dose; NDr = not determined.
96
Isopropanol
-------
FINAL
9-16-2014
Polynomial Model with 0.95 Confidence Level
dose
09:24 06/18 2013
Figure C-l. Selected BMD Model (Polynomial) Output for Decreased Fetal Body Weight
in Female Rabbits (Tyl et al., 1994)
Text Output for Polynomial BMD Model for Decreased Fetal Body Weight in Female
Rabbits (Tyl et al., 1994)
Polynomial Model. (Version: 2.16; Date: 05/26/2010)
Input Data File: C:\Documents and Settings\JKaiser\Desktop\modeling
results\ply_fetwet_isop_frabs_tyl_Ply-ModelVariance-BMR05-RestrictDown.(d)
Gnuplot Plotting File: C:\Documents and Settings\JKaiser\Desktop\modeling
results\ply_fetwet_isop_frabs_tyl_Ply-ModelVariance-BMR05-RestrictDown.pit
Thu Jul 25 09:27:59 2013
BMDS Model Run
The form of the response function is:
Y[dose] = beta_0 + beta_l*dose + beta_2*dose/s2 + ...
Dependent variable = mean
Independent variable = dose
97
Isopropanol
-------
FINAL
9-16-2014
The polynomial coefficients are restricted to be negative
The variance is to be modeled as Var(i) = exp(lalpha + log(mean(i)) * rho)
Total number of dose groups = 4
Total number of records with missing values = 0
Maximum number of iterations = 250
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
lalpha = 3.92863
rho = 0
beta_0 = 49.834
beta_l = -0.0104
beta 2 = -9.02778e-006
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -beta_l
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
lalpha rho beta_0 beta_2
lalpha 1 -1 0.081 -0.15
rho -1 1 -0.081 0.15
beta_0 0.081 -0.081 1 -0.55
beta 2 -0.15 0.15 -0.55 1
the user,
Parameter Estimates
Interval
Variable
Limit
lalpha
53.3455
rho
0.0628836
beta_0
51.2614
beta_l
beta_2
006
Estimate
28 . 6794
-6.46495
49.2116
0
-3.0586e-005
Std. Err.
12 .585
3.26642
1.04584
NA
1. 40009e-005
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
4.01327
-12.867
47.1618
-5 . 80273e-005
-3.14 4 63e-
Table of Data and Estimated Values of Interest
Dose N Obs Mean Est Mean Obs Std Dev Est Std Dev Scaled Res.
98
Isopropanol
-------
FINAL
9-16-2014
0
15
49.8
120
13
48.7
240
15
46.6
480
11
42.8
49.2 7.28
48.8 3.82
47.4 6.55
42.2 10.1
5.73 0.364
5.9 -0.0557
6.45 -0.481
9.44 0.22
Model Descriptions for likelihoods calculated
Model A1: Yij = Mu(i) + e(ij)
Var{e(ij)} = SigmaA2
Model A2: Yij = Mu(i) + e(ij)
Var{e(ij)} = Sigma(i)^2
Model A3: Yij = Mu(i) + e(ij)
Var{e(ij)} = exp(lalpha + rho*ln(Mu(i)))
Model A3 uses any fixed variance parameters that
were specified by the user
Model R: Yi = Mu + e(i)
Var{e(i)} = Sigma^2
Likelihoods of Interest
Model
A1
A2
A3
fitted
R
Log(likelihood)
-130.995075
-125.772468
-127.533879
-128.900848
-134.426485
# Param's
5
8
6
4
2
AIC
271.990150
267.544936
267.067758
265.801696
272.852970
Explanation of Tests
Test 1:
Test
Test
Test
Do responses and/or variances differ among Dose levels?
(A2 vs. R)
Are Variances Homogeneous? (A1 vs A2)
Are variances adeguately modeled? (A2 vs. A3)
Does the Model for the Mean Fit? (A3 vs. fitted)
(Note: When rho=0 the results of Test 3 and Test 2 will be the same.)
Tests of Interest
Test
-2*log(Likelihood Ratio) Test df
p-value
Test
Test
Test
Test
17.308
10.4452
3.52282
2.73394
0. 008215
0.01514
0.1718
0.2549
The p-value for Test 1 is less than .05. There appears to be a
difference between response and/or variances among the dose levels
It seems appropriate to model the data
The p-value for Test 2 is less than .1. A non-homogeneous variance
model appears to be appropriate
The p-value for Test 3 is greater than .1. The modeled variance appears
to be appropriate here
99
Isopropanol
-------
FINAL
9-16-2014
The p-value for Test 4 is greater than . 1. The model chosen seems
to adequately describe the data
Benchmark Dose Computation
Specified effect = 0.05
Risk Type = Relative risk
Confidence level = 0.95
BMD = 2 83.633
BMDL = 119.54
100
Isopropanol
-------
FINAL
9-16-2014
APPENDIX D. REFERENCES
ACGIH (American Conference of Governmental Industrial Hygienists). (2013). 2013 TLVs and
BEIs. Based on documentation of the threshold limit values for chemical substances and
physical agents and biological exposure indices. Cincinnati, OH.
Allen. B; Gentry. R; Shipp. A; Van Landingham. C. (1998). Calculation of benchmark doses for
reproductive and developmental toxicity observed after exposure to isopropanol. Regul
Toxicol Pharmacol 28: 38-44. http://dx.doi.org/10.1006/rtph.1998.1226
AT SDR (Agency for Toxic Substances and Disease Registry). (2013). Minimal risk levels
(MRLs) for hazardous substances. Atlanta, GA: Agency for Toxic Substances and
Disease Registry (ATSDR). Retrieved from http://www.atsdr.cdc.gov/mrls/index.asp
Bates. HK; Mckee. RH; Bieler. GS: Gardiner. TH: Gill. MW: Strother. DE: Masten. LW. (1994).
Developmental neurotoxicity evaluation of orally administered isopropanol in rats.
Fundam Appl Toxicol 22: 152-158. http://dx.doi.org/10.1006/faat.1994.1018
Bevan. C: Tyler. TR; Gardiner. TH: Kapp. RW. Jr; Andrews. L; Beyer. BK. (1995). Two-
generation reproduction toxicity study with isopropanol in rats. J Appl Toxicol 15: 117-
123. http://dx.doi.org/10.1002/iat.255015021Q
BIBRA (British Industrial Biological Research Association). (1986). A pilot one-generation
study with isopropyl alcohol in rats. (Unpubl report no. 0570/1/86). Carshalton, Surrey,
England: British Industrial Biological Research Association (BIBRA).
BIBRA (British Industrial Biological Research Association). (1987). A teratology study with
isopropyl alcohol in rats. (Unpubl. Report no. 0570/2/86). Carshalton, Surrey, England:
British Industrial Biological Research Association (BIBRA).
BIBRA (British Industrial Biological Research Association). (1988). A single generation
reproduction and embryotoxicity study with isopropyl alcohol in rats. (Report No.
0570/4/90.). Carshalton, Surrey, England: British Industrial Biological Research
Association (BIBRA).
BIBRA (British Industrial Biological Research Association). (1991). BIBRA toxicity profile of
para-isopropyltoluene. (NTIS/02988074_3). Carshalton, Surrey, England: British
Industrial Biological Research Association (BIBRA).
Blow. BJ: Ge. Y; Safdar. Z. (2012). Respiratory failure, lung infiltrates, and hemoptysis in a
woman with chronic isopropyl alcohol inhalation [Letter], Ther Adv Respir Dis 6: 189-
193. http://dx.doi.org/10.1177/1753465812439616
Burleigh-Flaver. H; Garman. R; Neptun. D; Bevan. C: Gardiner. T; Kapp. R; Tyler. T; Wright.
G. (1997). Isopropanol vapor inhalation oncogenicity study in Fischer 344 rats and CD-I
mice. Fundam Appl Toxicol 36: 95-111. http://dx.doi.org/10.1006/faat.1996.2284
Burl eigh-Fl aver. H; Gill. M; Hurley. J: Bevan. C: Gardiner. T; Kapp. R; Tyler. T; Wright. G.
(1998). Motor activity effects in female Fischer 344 rats exposed to isopropanol for 90
days. J Appl Toxicol 18: 373-381.
Burl eigh-Fl aver. HP: Gill. MW: Strother. DE: Masten. LW: Mckee. RH: Tyler. TR: Gardiner. T.
(1994). Isopropanol 13-week vapor inhalation study in rats and mice with neurotoxicity
evaluation in rats. Fundam Appl Toxicol 23: 421-428.
http://dx.doi.org/10.1006/faat.1994.1123
BushyRun (Bushy Run Research Center). (1994). Isopropanol: Ninety-day vapor inhalation
neurotoxicity study in female fischer 344 rats, with cover letter dated 05/16/94. Export,
PA. http://www.ntis.gov/search/product.aspx?ABBR=OTS0557397
101
Isopropanol
-------
FINAL
9-16-2014
Cal/EPA (California Environmental Protection Agency). (2012). All OEHHA acute, 8-hour and
chronic reference exposure levels (chRELs) as on February 2012. Sacramento, CA:
Office of Environmental Health Hazard Assessment.
http://www.oehha.ca.gov/air/allrels.html
Cal/EPA (California Environmental Protection Agency). (2014). All OEHHA acute, 8-hour and
chronic reference exposure levels (chRELs) as of June 2014. Sacramento, CA: Office of
Health Hazard Assessment, http://www.oehha.ca.gov/air/allrels.html
ChemicalBook (ChemicalBook Inc.). (2008). Isopropanol CASRN 67-63-0.
Clark. JD. (2010). Isopropyl alcohol intoxication. J EmergNurs 36: 81-82.
http://dx.doi.Org/10.1016/i.ien.2009.10.006
Clark. LH; Setzer. RW: Barton. HA. (2004). Framework for evaluation of physiologically-based
pharmacokinetic models for use in safety or risk assessment. Risk Anal 24: 1697-1717.
http://dx.doi.Org/10.llll/i.0272-4332.2004.00561.x
Clewell. HJ. Ill: Gentry. PR: Gearhart. JM; Covington. TR; Banton. MI; Andersen. ME. (2001).
Development of a physiologically based pharmacokinetic model of isopropanol and its
metabolite acetone. Toxicol Sci 63: 160-172.
Daniel. PR; Mcanallev. BH; Garriott. JC. (1981). Isopropyl alcohol metabolism after acute
intoxication in humans. J Anal Toxicol 5: 110-112.
Desv. O; Carignan. D; Caruso. M; de Campos-Lima. PO. (2008). Immunosuppressive effect of
isopropanol: Down-regulation of cytokine production results from the alteration of
discrete transcriptional pathways in activated lymphocytes. J Immunol 181: 2348-2355.
Eastman Kodak (Eastman Kodak Company). (1995). Dermal absorption and pharmacokinetics of
isopropanol in the male and female f-344 rat with cover letter dated 10/24/95. Rochester,
NY. http://www.ntis.gov/search/product.aspx?ABBR=OTS0572874
Ernstgard. L; Gull strand. E; Lof. A; Johanson. G. (2002). Are women more sensitive than men to
2-propanol and m-xylene vapours? Occup Environ Med 59: 759-767.
http://dx.doi.Org/10.l 136/oem. 59.11.759
Ernstgard. L; Sjogren. B; Warholm. M; Johanson. G. (2003). Sex differences in the
toxicokinetics of inhaled solvent vapors in humans 2. 2-propanol. Toxicol Appl
Pharmacol 193: 158-167. http://dx.doi.Org/10.1016/i.taap.2003.08.005
Faber. WD; Pavkov. KL; Gingell. R. (2008). Review of reproductive and developmental toxicity
studies with isopropanol [Review], Birth Defects Res B Dev Reprod Toxicol 83: 459-
476. http://dx.doi.org/10.1002/bdrb.20167
Gaudet. MP; Fraser. GL. (1989). Isopropanol ingestion: Case report with pharmacokinetic
analysis. Am J Emerg Med 7: 297-299. http://dx.d0i.0rg/l0.1016/0735-6757(89^)90174-5
Gentry. PR; Covington. TR; Andersen. ME; Clewell. HJ. III. (2002). Application of a
physiologically based pharmacokinetic model for isopropanol in the derivation of a
reference dose and reference concentration [Review], Regul Toxicol Pharmacol 36: 51-
68. http://dx.doi.org/10.1006/rtph.2002.154Q
Gentry. PR; Covington. TR; III. CH; Anderson. ME. (2003). Application of a physiologically
based pharmacokinetic model for reference dose and reference concentration estimation
for acetone. J Toxicol Environ Health A 66: 2209-2225.
http://dx.doi.org/10.1080/713853996
Haseman. JK; Arnold. J; Eustis. SL. (1990). Tumor incidences in Fischer 344 rats: NTP
historical data. In GA Borman; SL Eustis; MR Elwell; CA Montgomery, Jr.; WF
MacKenzie (Eds.), Pathology of the Fischer rat (pp. 555-564). San Diego, CA: Academic
Press.
102
Isopropanol
-------
FINAL
9-16-2014
Huizer. D; Oldenkamp. R; Ragas. AM; van Rooii. JG; Huiibregts. MA. (2012). Separating
uncertainty and physiological variability in human PBPK modelling: The example of 2-
propanol and its metabolite acetone. Toxicol Lett 214: 154-165.
http://dx.doi.Org/10.1016/i.toxlet.2012.08.016
IARC (International Agency for Research on Cancer). (1999). Isopropanol [IARC Monograph],
In Re-evaluation of some organic chemicals, hydrazine and hydrogen peroxide (pp. 1027-
1036). Lyon, France. http://monographs.iarc.fr/ENG/Monographs/vol71/mono71-45.pdf
Kaneko. T; Wang. PY; Sato. A. (1994). Partition coefficients of some acetate esters and alcohols
in water, blood, olive oil, and rat tissues. Occup Environ Med 51: 68-72.
Killeen. C: Meehan. T; Dohnal. J: Leikin. JB. (2011). Pseudorenal insufficiency with isopropyl
alcohol ingestion. Am J Ther 18: ell3-ell6.
http://dx.doi.org/10.1097/MJT.0b013e3181c96Qcb
Krieg. JC. (2008). Isopropyl alcohol poisoning from cast application. A case report. J Bone Joint
Surg Am 90: 1998-1999. http://dx.doi.Org/10.2106/JBJS.H.00053
Leeper. SC: Almatari. AL; Ingram. JD; Ferslew. KE. (2000). Topical absorption of isopropyl
alcohol induced cardiac and neurologic deficits in an adult female with intact skin. Vet
Hum Toxicol 42: 15-17.
Lynch. J: Hanis. NM; Bird. MG: Murray. KJ; Walsh. JP. (1979). An association of upper
respiratory cancer with exposure to diethyl sulfate. J Occup Med 21: 333-341.
Mcfadden. SW: Haddow. JE. (1969). Coma produced by topical application of isopropanol.
Pediatrics 43: 622-623.
Natowicz. M; Donahue. J: Gorman. L; Kane. M; Mckissick. J: Shaw. L. (1985). Pharmacokinetic
analysis of a case of isopropanol intoxication. Clin Chem 31: 326-328.
Nelson. BK; Brightwell. WS: Krieg. EF. Jr. (1990). Developmental toxicology of industrial
alcohols: A summary of 13 alcohols administered by inhalation to rats. Toxicol Ind
Health 6: 373-387.
Nelson. BK: Brightwell. WS: Mackenzie-Taylor. PR: Khan. A: Burg. JR; Weigel. WW. (1988).
Teratogenicity of n-propanol and isopropanol administered at high inhalation
concentrations to rats. Food Chem Toxicol 26: 247-254.
NIOSH. (2010). Isopropyl alcohol. In NIOSH pocket guide to chemical hazards. Atlanta, GA:
Centers for Disease Control and Prevention.
http://www.cdc.gov/niosh/npg/npgd0359.html
NTP (National Toxicology Program). (2011). Report on carcinogens: Twelfth edition (12th ed.).
Research Triangle Park, NC: U.S. Department of Health and Human Services, Public
Health Service, National Institutes of Health.
http://ntp.niehs.nih.gov/ntp/roc/twelfth/rocl2.pdf
OSHA (Occupational Safety & Health Administration). (2011). Air contaminants: occupational
safety and health standards for shipyard employment, subpart Z, toxic and hazardous
substances. (OSHA Standard 1915.1000). Washington, DC: U.S. Department of Labor.
http://www.osha.gov/pls/oshaweb/owadisp.show document?p table=STANDARDS&p
id=l0286
OTS (Office of Toxic Substances). (1987). Acute percutaneous toxicity study in rabbit with
cover letter dated 020987. Washington, DC.
http://www.ntis.gov/search/product.aspx?ABBR=OTSQ513336
Parker. KM: Lera. TA. Jr. (1992). Acute isopropanol ingestion: Pharmacokinetic parameters in
the infant. Am J Emerg Med 10: 542-544. http://dx.doi.org/10.1016/Q735-
6757(92)90179-2
103
Isopropanol
-------
FINAL
9-16-2014
Pilegaard. K; Ladefoged. O. (1993). Toxic effects in rats of twelve weeks' dosing of 2-propanol,
and neurotoxicity measured by densitometric measurements of glial fibrillary acidic
protein in the dorsal hippocampus. In Vivo 7: 325-330.
Rehman. HU. (2012). A woman with ketoacidosis but not diabetes. B M J (Online) 344: el535.
Rehman. IH; I
-------
FINAL
9-16-2014
U.S. EPA (U.S. Environmental Protection Agency). (1994b). Methods for derivation of
inhalation reference concentrations and application of inhalation dosimetry. (EPA/600/8-
90/066F). Research Triangle Park, NC: U.S. Environmental Protection Agency,
Environmental Criteria and Assessment Office.
http://cfpub. epa.gov/ncea/cfm/recordisplav. cfm?deid=71993
U.S. EPA (U.S. Environmental Protection Agency). (2002). A review of the reference dose and
reference concentration processes. (EPA/630/P-02/002F). Washington, DC: U.S.
Environmental Protection Agency, Risk Assessment Forum.
http://cfpub. epa.gov/ncea/cfm/recordisplav. cfm?deid=51717
U.S. EPA (U.S. Environmental Protection Agency). (2005). Guidelines for carcinogen risk
assessment. (EPA/630/P-03/001F). Washington, DC: U.S. Environmental Protection
Agency, Risk Assessment Forum, http://www.epa.gov/cancerguidelines/
U.S. EPA (U.S. Environmental Protection Agency). (2010). Benchmark dose software (BMDS)
(Version 2.1.2 (Final Release)) [Computer Program], RTP, NC: National Center for
Environmental Assessment. Retrieved from http://www.epa.gov/NCEA/bmds/new.html
U.S. EPA (U.S. Environmental Protection Agency). (2011a). Health effects assessment summary
tables (HEAST). Washington, DC: U.S. Environmental Protection Agency, Office of
Emergency and Remedial Response, http://epa-heast.ornl. gov/
U.S. EPA (U.S. Environmental Protection Agency). (201 lb). Recommended use of body weight
3/4 as the default method in derivation of the oral reference dose. (EPA/100/R11/0001).
Washington, DC: U.S. Environmental Protection Agency, Risk Assessment Forum.
http://www.epa.gov/raf/publications/interspecies-extrapolation.htm
U.S. EPA (U.S. Environmental Protection Agency). (2012a). 2012 Edition of the drinking water
standards and health advisories. (EPA/822/S-12/001). Washington, DC: Office of Water.
http://water.epa.gov/action/advisories/drinking/upload/dwstandards2012.pdf
U.S. EPA (U.S. Environmental Protection Agency). (2012b). Benchmark dose technical
guidance. (EPA/100/R-12/001). Washington, DC: Risk Assessment Forum.
http://www.epa.gov/raf/publications/pdfs/benchmark dose guidance.pdf
U.S. EPA (U.S. Environmental Protection Agency). EPA's Integrated Risk Information System
Program. Progress report and report to Congress. Washington, DC: U.S. Environmental
Protection Agency, IRIS. Retrieved from http://www.epa.gov/iris/index.html
U.S. EPA (U.S. Environmental Protection Agency). (2014). Integrated risk information system
(IRIS) [Database], Washington, DC: U.S. Environmental Protection Agency, Integrated
Risk Information System. Retrieved from http://www.epa.gov/iris/
Vivier. PM; Lewander. WJ: Martin. HF; Linakis. JG. (1994). Isopropyl alcohol intoxication in a
neonate through chronic dermal exposure: A complication of a culturally-based umbilical
care practice. Pediatr Emerg Care 10: 91-93.
WHO (World Health Organization). Online catalog for the Environmental Health Criteria Series.
Geneva, Switzerland: World Health Organization (WHO).
http://www.who.int/ipcs/publications/ehc/en/
Zeiger. E; Anderson. B; Haworth. S: Lawlor. T; Mortelmans. K. (1992). Salmonella
mutagenicity tests: V Results from the testing of 311 chemicals. Environ Mol Mutagen
19: 2-141. http://dx.doi.org/10.1002/em.28501906Q3
105
Isopropanol
------- |