Registration Dossier

Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (EPA) similar to OECD guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
GLP compliance:
yes
Remarks:
United States Environmental Protection Agency TSCA: Good Laboratory Practice Standards, 40 CFR 792
Test type:
acute toxic class method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): s-MOIPA
- Physical state: clear, light-yellow liquid
- Purity test date: 94.1 - 95.3%
- Lot/batch No.: 7/11/97
- Storage condition of test material: the test material was stored at room temperature. A reserve sample of the test material was taken and will be retained in a freezer set to maintain a temperature of -20°C±1°C

Test animals

Species:
rat
Strain:
other: Crl:CD®(SD)BR
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: procured from Charles River Laboratories, Inc., Portage, Michigan on February 9 and 23 and Mareh 9, 1998
- Age at study initiation: young adult albino rats (8 to 12 weeks)
- Weight at study initiation: 204 to 299 g
- Fasting period before study: not specified
- Housing: the animals were separated by sex and group housed in suspended, stainless steel cages
- Diet (e.g. ad libitum): Rodent Diet #8604 (Harlan Teklad)
- Water (e.g. ad libitum): tap water
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 26°C
- Humidity (%): 50±20%
- Photoperiod (hrs dark / hrs light): 12/12

The animals were provided continuous access to diet and water except for 17 to 20 hours before test material administration when the diet, but not water, was withheld. The diet is routinely analyzed by the manufacturer for nutritional components and environmental contaminants. Samples of the water are periodically analyzed. There were no known contaminants in the diet or water at levels that would be expected to interfere with or affect the results of the study.
In cases where variations from these conditions existed, they were documented and considered to have had no adverse effect on the study outcome.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 100 mg/kg level: the test material was mixed with distilled water to a concentration of 0.02 g/ml; 500, 1000, and 1500 mg/kg levels: undiluted test material. Individual dose calculated for each animal based on its fasted body weight.
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 0.02 g/ml (only 100 mg/kg dose level)
- Amount of vehicle (if gavage): 5 ml/kg of body weight
- Justification for choice of vehicle: the prepared test material mixture appeared to be a solution.
Doses:
100, 500, 1000, and 1500 mg/kg of body weight.
No. of animals per sex per dose:
5 (exception: only 5 males in the 1500 mg/kg group)
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: clinical observations were conducted at 1, 2.5, and 4 hours after test material administration and daily thereafter for 14 days. Mortality checks were conducted twice a day (morning and afternoon) for 13 days after test material administration and again the morning of Day 14.
Body weights were determined before test material administration (Day 0). Additional body weights were determined at Day 7, at termination of the respective in-life phase (Day 14), or at death (or moribund sacrifice) when survival exceeded one day.
- Necropsy of survivors performed: yes; at termination of the respective in-life phase for each dose level, surviving animals were euthanized. All animals, whether found dead during the study, sacrificed in a moribund condition, or euthanized at study termination, were subjected to an abbreviated gross necropsy examination and any abnormalities were recorded.
- Other examinations performed: after necropsy, the animals were discarded and only those tissues with lesions were collected for possible histopathological evaluation.
Statistics:
For statistical purposes in this study, the animals sacrificed in a moribund condition were considered to have died due to the test material. Using this information, the estimated LD50 values for males, females, and the sexes combined were determined by a Computer program using a modified Behrens-Reed-Muench cumulant method. No other statistical evaluations were required by the protocol.

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LD50
Effect level:
ca. 334 mg/kg bw
95% CL:
190 - 588
Remarks on result:
other: see below
Sex:
female
Dose descriptor:
LD50
Effect level:
ca. 224 mg/kg bw
95% CL:
112 - 445
Remarks on result:
other: see below
Sex:
male
Dose descriptor:
LD50
Effect level:
ca. 583 mg/kg bw
95% CL:
278 - 1 223
Remarks on result:
other: see below
Mortality:
A summary of the observed mortality along with the LD50 values and 95% confidence limits are in Table 1. Three male and three female animals treated at 500 mg/kg were found dead within 7 days of test material administration. Two additional females treated at 500 mg/kg were sacrificed in a moribund condition on Days 1 and 10, respectively, and are counted as having died on study. Three male and four female animals treated at 1000 mg/kg were found dead within 1 day of test material administration. The remaining female treated at 1000 mg/kg was sacrificed in a moribund condition on Day 1 and is counted as having died on study. All five male animals treated at 1500 mg/kg were found dead within 1 day of test material administration. Based on the mortality observed in the study (considering the animals which were sacrificed in a moribund condition as having died on study), the estimated oral LD50 values in rats were determined to be 583, 224, and 334 mg/kg for males, females, and the sexes combined, respectively.
Clinical signs:
All animals treated at 100 mg/kg appeared normal throughout the study with the exception of one male which exhibited a slight red discharge in the urogenital area on Day 2.
Clinical signs of toxicity observed at the 500 mg/kg dose level included thin appearance, flaccidity, sensitivity to touch, hypoactivity, staggered gait, red-stained face, lacrimation, gasping, red discharge around the nose and mouth, wet area around the mouth, and wet/red-/or yellow-stained urogenital area. One surviving male returned to a normal appearance by Day 3 after treatment. The other surviving male continued to exhibit clinical signs until study termination.
Clinical signs of toxicity observed at the 1000 mg/kg dose level included hunched posture, hypoactivity, staggered gait, prostration, cold to touch, red-stained face, lacrimation, wet area around the mouth, brown-stained mouth, tremors, red discharge in urogenital area, and red-/brown-stained urogenital area. The two surviving males treated at this dose level returned to a normal appearance by Day 3 after treatment.
Clinical signs of toxicity observed prior to death in the males treated at the 1500 mg/kg dose level included hypoactivity, staggered gait, absence of righting reflex, red-stained face, mydriasis, dyspnea, and clonic convulsions.
Body weight:
Individual and mean body weights and body weight gains are shown in Table 2. Animals surviving to the end of the observation period exhibited body weight gain during the study with the exception of one male at 500 mg/kg and one male at 1000 mg/kg which exhibited weight losses of 61 and 24 g, respectively, during the first week. The one male treated at 500 mg/kg also exhibited an additional weight loss of 17 g during the second week, while the one male treated at 1000 mg/kg showed recovery from the first week weight loss.
Gross pathology:
At necropsy, most of the findings observed were in the animals that died or that were sacrificed in a moribund condition. These changes pertained to the content (containing dark-red fluid) and coloration changes (dark-red areas) in the gastrointestinal tract. In some of the animals treated at 500 mg/kg there were adhesions between the stomach and adjacent organs or tissues. These are considered to be test material-related. All other findings are considered to be incidental and unrelated to the test material.
Other findings:
not applicable

Any other information on results incl. tables

Test Mixture:

AnalysisThe results of the analysis indicate that the mixture was homogeneous and that the mean value was within 94% of the targeted concentration of 20 mg/ml.

Table 1: Mortality Summary

 

Dose level (mg/kg)

Mortality result; number died or sacrificed/number dosed*

Males

Females

100

0/5

0/5

500

3/5; days 1 (2) and 7 (1)

5/5; days 1 (3+), 6 (1) and 10 (1)

1000

3/5; day 1 (3)

5/5; days 1 (5+)

1500

5/5; Days 0 (4) and 1 (1)

-

* Superscript number indicates the number of animals found dead or sacrificed on the indicated day; +One animal was sacrificed in a moribund condition.

 

Table 2: Mean body weight and body weight gain

 

Treatment group (mg/kg)

 

Sex

Mean body weight and body weight gain

Day 0

Day 7

Day 7

Weight

Gain*

Weight

Gain*

100

Male

293

358

65

296

103

Female

241

281

40

294

53

500

Male

222

212

-13

246

17

Female

212

171

-3

-

-

1000

Male

291

309

21

268

80

Female

237

-

-

-

-

1500

Male

233

-

-

-

-

* Gain from day 0 in body weight; - not applicable

 

Applicant's summary and conclusion