EPA 730-F-98-005
United 8Ut«t Offlo* of PravcntfOti. P»rtklde« EPA-737-F-98
Environment*! Protection *nd Taxte Subttaneti March 1998
Agoncy _ Wathlnaton DC 20460
Offlo* of PeirtcWt Program*
New Pesticide
Fact Sheet
1. Description of the Chemical;
Generic Name: ('[2,5-dioxo-3-(2-propynyl)-l-imidazolidinyl]
methyl (1R)- CIST trans-chrysanthemate
Common Name: im'Iprothrin
Trade Name: Prialle
EPA Shaughnessy Code (OPP Chemical Code): 004006
Chemical Abstracts Service (CAS) Number: 72963-72-5
Year of Initial Registration: MARCH 1998
Pesticide Type: Insecticide
Chemical Family: Synthetic Pyrethroid
Producer: Sumitomo Chemical Company Limited
2. Use Patterns and Formulations;
Application Sites: Indoor/ non- food use (residences homes,
non- food areas of restaurants, schools, warehouses, hotels)
Type and Method of Application: Crack and crevice and spot
application. i
Types of Formulation: 50.5% Manufacturing Use Product
(MUP); 16.0% intermediate product (plus d-phenothrin and MGK
264); 0.4% aerosol spray (plus d-phenothrin and MGK 264);
0.1% aerosol spray (plus cypermethrin).
Target Pest: Roaches, Waterbugs, Ants, Silverfish, Crickets
and Spiders
Nrtoiul Tichnlcu MonmUon a
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3. Scienca Findings!
Summary Statement: Imiprothrin technical grade and MUP are
of a low acute toxicity profile i.e. all toxicity categories
are either III/IV (Caution). Although imiprothrin enlisted a
mild sensitization based upon the results of a guinea pig
maximation test with the technical grade active ingredient
it was negative in a second study with the technical and
negative in two sensitization studies with the MUP. The end
use (EP) products all have a low order of acute toxicity and
were assigned a!Toxicity Category III (Caution) based on the
acute dermal and primary eye or skin irritation routes of
exposure. , ;
i :
Subchronic oral', dermal and inhalation studies have
been submitted and found acceptable in the rat. The
NOEL's were 100 ppm, 300 mg/kg/bw and 22.0 mg/mj
respectively. Based on the results of developmental
toxicity studies in rabbits imiprothrin is not a
developmental toxicant at dose levels which did not
also produce maternal toxicity. A range of mutagenicity
tests revealed no evidence that imiprothrin has
mutagenic potential. Chronic feeding, carcinogenic
reproduction and metabolism studies were not submitted
since these studies are not required for a non- food
use registration.
Based upon relevant toxicity studies noted above and
the proposed use! pattern the Toxicology Endpoint
Selection Committee(TESC) concluded that the only risk
assessment required was for inhalation exposure. The
occupational inhalation exposure for the use of this
chemical was calculated to be 0.000143 mg/kg/day.
Therefore, using the TESC recommended NOEL of 22.0
mg/m3 from the 28 day inhalation study in the rat, the
Margin of Exposure (MOE) for occupational inhalation is
greater than 25,000. A MOE of this size is sufficiently
large to alleviate concern for exposure from the indoor
uses of imiprothrin. Due to the conservative exposure
assumptions (six hours for five days per week) used in
the calculation of occupational inhalation exposure, no
calculation was done for residential exposure. The MOE
for residential inhalation would be even larger than
25,000 MOE for occupational inhalation.
Two avian dietary, and three fresh- water aquatic acute
toxicity studies were submitted to support the proposed
end-use and manufacturing use product. The submitted
toxicity studies' are adequate to satisfy the basic
ecological toxibity data requirements except for a data
gap of an aviarij acute oral toxicity study. However, the
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study is waived!due to the unlikeliness of exposure
from this indoor use pattern and the low toxicity to
birds. The chem'jLcal is practically non-toxic to birds
based on the rejsxilts of the subacute dietary toxicity
studies. The LCJ0j values for mallards and bobwhite
quails are bothl greater than 5620 ppm.
(i
Due to the indoor use pattern environmental persistence
(soil and water), mobility in soil and water and
bioaccumulation are not of concern at this time. The
only enviromental fate data submitted was an hydrolysis
study conducted on imiprothrin at pH 5, 7 and 9.
Additional outdoor uses of imiprothrin will require
additional supporting environmental fate data.
The proposed uses (residential homes, non-food areas of
restaurants, schools, warehouses, hotels, etc.) of this
new active ingredient are such that the only risk
concern is through the inhalation route in an
occupational and residential setting. A food-use
registration has not been requested at this time for
this chemical and therefore, no concern from dietary
(food and water|! risk is anticipated.
CHEMICAL CHARACTERISTICS: Technical Grade imiprothrin
Physical: Liquid '
Color: Golden yellow (amber)
odor: Sweet (Slightly sweet)
Melting Point: NA
Density: 0.979 g/ml (1.122 g/ml)
Molecular Formula: C,gH22N2O3
Vapor Pressure: 1.39 mm Hg at 25 degrees C
8.64 mm Hg at 35 degrees C
Octanol/Water Partition Coefficient:P= 7.92 x 102 at 25 degrees C
Log n^= 2.9
pH: 5.22 (5.95)
Stability: Stable toj metals, metal ions, sunlight and elevated
temperature
Oxidizing of Reducing Action: Product does not contain oxidizing
or reducing agents. :|
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Toxicology Characteristics: Technical Grade imiprothrin
Acute Toxicity
Guideline
No.
81-1
81-2
81-3
81-4
81-5
81-6
Study Type
Acute Oral
Acute Dermal
Acute Inhalation
Primary Eye
Irritation
Primary Skin
Irritation
Dermal
Sensitization
HRID #(S).
43750718
43750720
43750722
43750724
43750724
43750726;
43750727
Results
Rat LDj, =1800
rag/kg for males
and 900 mg/kg for
females;
neurological signs
(tremor, ataxic
gait and decreased
spontaneous
activity) within
30 mts. of
exposure
Rat LDjo =>2000
mg/kg for males
and females. No
clinical signs of
toxicity observed.
Rat LC,, =>1.2
mg/1 for males and
females; at 0.418
tng/L (LTD);
neurological signs
(ataxic gait and
tip toe gait) seen
1 hour post-
exposure
Rabbit: Non-
irritating
Rabbit:. Non-
irritating
Guinea pig: Mild-
sensitizer using
Magnusson and
Kligman test;non-
sensitizer using
Buehler method
Toxicity
Category
III
III
III
IV
IV
NA
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Subchronio Toxicitvt
A 13-week oral rat study showed significantly body weight loss
and suppression of feeding rate at doses of 3000, 6000 or 10000
ppm. Hematology and blood chemistry values were also altered at
these doses as compared to the lowest dose (100 ppm) and the
control group. The weights of the liver and other organs
increased in the three higher dose groups. The NOEL was judged to
be 100 ppm and the LOEL to be 3000 ppm.
A 21 day dermal study with rats conducted at 100, 300 or 1000
mg/kg body weight showed an increase in the incidence of dermal
acanthosis and hyperkeratosis in the high dose group. The NOEL
was 300 mg/kg body weight based on these effects and the LOEL was
1000 mg/kg body weight/day.
A 4- week inhalation study exposed rats to 2.4, 22.0 or 186 mg/m3
of imiprothrin with a median aerodynamic diameter of 0.80 to 0.86
urn. The NOEL was 22.0 mg/m3 based on lower total body weight
gain, changes in hematblogy and clinical chemistry parameters,
and changes in liver and the salivary glands. The LOEL was 186
mg/m3.
Developmental Toxicityt
Rabbits were fed with imiprothrin at 30, 100 or 300 mg/kg body
weight/day. The maternal NOEL was 30 mg/kg/body weight/day based
upon suppressed body weight gain and food consumption, while the
LOEL was 100 mg/kg body weight/day. At 300 mg/kg body weight/day
premature labor, abortion and mortality were noted. The
developmental NOEL was not determined (i.e. it was less than 100
mg/kg body weight/day), on the basis of decreased fetal body
weight and frontal bone hypoplasia. An increased incidence of the
27th pre- sacral vertebra occurred in all treatment groups. The
LOEL was not determined.
An additional developmental study was conducted on rabbits at
doses of 3, 10 or 30 mg/kg body weight/day to determine the
developmental end points which the earlier study had not been
able to define. This study showed no treatment related
developmental effects. The developmental NOEL, based on both
studies, was 30 mg/kg/body weight/day while the LOEL was 100
ing/kg/body weight/day.
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Mutagenicitv;
Imiprothrin was subjected to Ames tests with Salmonella and with
E. coli. Both tests showed imiprothrin not to be mutagenic. An in
vitro gene mutation assay with Chinese hamster cells showed that
this chemical does not have the potential to cause gene
mutations. An in vitro chromosome aberration assay showed that
imiprothrin did have the potential to cause chromosome
aberrations in Chinese hamster lung cells in the presence of S9
metabolic activation. An in vivo mouse bone marrow micronucleus
test did not show chromosome damage. Two in vivo/in vitro
unscheduled DNA synthesis tests were conducted with primary rat
hepatocytes; time course and dose response. Neither UDS test
showed an increase in such synthesis. The weight- of- evidence
indicates imiprothrin is not genotoxic.
Toxicology Characteristics;
End- Use Formulations:
A. Pralle (50.5% imiprothrin)
Acute Oral Toxicity (Rats: male and female): The acute
oral LDJO was 4500 mg/kg for males and 2400 mg/kg for
females. Toxicology Category III
Acute Dermal Toxicity (Rats: male and female) The acute
dermal LD^ is greater than 2000 mg/kg. Toxicity
Category III.
Acute Inhalation Toxicity (Rats: male and female) The
acute inhalation LCJO is greater than 2 mg/L for male
and female rats. Toxicity Category IV.
Primary Eye Irritation (Rabbits) non- irritating.
Toxicity Category IV.
Primary Dermal Irritation (Rabbits) non- irritating.
Toxicity Category IV.
Dermal Sensitization- Not a sensitizer.
B. Multicide Intermediate 2734 (16% imiprothrin, 11.2% d-
phenothrin, 52.8% MGK 264)
Acute Oral Toxicity (Rats: male and female): Combined
LDj0 is greater than 5 g/kg. Toxicology Category IV.
Acute Dermal Toxicity (Rabbits: male and female)
Combined LD30 is greater than 2 g/kg. Toxicity Category
III.
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Acute Inhalation Toxicity (Rabbits: male and female)
Combined LCJO is greater than 2.69 mg/L. Toxicity
Category IV.
Primary Eye Irritation (Rabbits) mild irritant.
Toxicity Category III.
Primary Dermal Irritation (Rabbits) non- irritating.
Toxicity Category IV.
Dermal Sensitization- Sensitizer.
c. Multicide Pressurized Roach Spray 27341 (0.4%
imiprothrin, 0.5% d- phenothrin, 1% MGK 264)
Acute Oral Toxicity (Rats: male and female): Combined
LD50 is greater than 5 g/kg. Toxicology Category IV.
Acute Dermal Toxicity (Rabbits: male and female)
Combined LDJO is greater than 2 g/kg. Toxicity Category
III.
Acute Inhalation Toxicity (Rabbits: male and female)
Combined LC50 is greater than 3.82 mg/L. Toxicity
Category IV.
Primary Eye Irritation (Rabbits) Mild irritant.
Toxicity Category III.
Primary Dermal Irritation (Rabbits) moderate
irritation. Toxicity Category III.
Dermal Sensitization- Sensitizer.
D. Raid Ant & Roach 17 (0.1% imiprothrin, 0.1% cypermethrin)
Acute Oral Toxicity (Rats: male and female): Combined
LDJO is greater than 5 g/kg. Toxicity Category IV.
Acute Dermal Toxicity (Rabbits: male and female)
Combined LD50 is greater than 5 g/kg. Toxicity Category
IV.
Acute Inhalation Toxicity (Rabbits: male and female)
Combined LCJO is greater than 5.1 mg/L. Toxicity
Category IV.
Primary Eye Irritation (Rabbits) No corneal irritation.
Toxicity Category IV.
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Primary Dermal Irritation (Rabbits) moderate
irritation. Toxicity Category III.
Dermal Sensitization- Not a dermal sensitizer.
ENVIROMENTAL FATE CHARACTERISTICS: Technical Grade imiprothrin
Hydrolysis Data- Imiprothrin degrades by pH sensitive
hydrolysis with calculated half-lives of less than one day at pH
9 and approximately 59 days at pH 7. Degradation did not occur at
pH 5. There was only one degradate which accounted for more than
10% of the radioactivity at pH 7 and 9. this compound was
identified as N-carbamoyl- N- propargyglycine (CPC).
ECOLOGICAL EFFECTS CHARACTERISTICS; Technical Grade imiprothrin
Freshwater Fish
Rainbow trout: LC50 = 0.038 ppm.
Aquatic Invertebrate
Daphia magna; ECX =0.051 ppm.
Avian Dietary
Bobwhite quail and mallard ducks: LC50 = are both
greater than 5620 ppm.
Warmwater Fish
Bluegill: LC50 =0.07 ppm.
SUMMARY OF DATA GAPS: There are no data gaps for this use.
CONTACT PERSON:
Linda DeLuise
Reviewer, PM-13
Insecticide Branch
Registration Division (7505C)
Office of Pesticide Programs
U.S. EPA
401 M St. SW
Washington, DC 20460
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Office Location and Telephone Number:
Rm. 200, Crystal Mall # 2
1921 Jefferson Davis Highway
Arlington, VA 22202
(703) 305-5428
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