Registration Dossier

Administrative data

Endpoint:
acute toxicity: dermal
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 870.1200 (Acute Dermal Toxicity)
GLP compliance:
yes
Remarks:
United States Environmental Protection Agency TSCA: Good Laboratory Practice Standards, 40 CFR 792
Test type:
standard acute 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.

Test animals

Species:
rabbit
Strain:
other: Hra:(NZW)SPF
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: albino rabbits of the Hra:(NZW)SPF strain were procured from Covance Research Products Inc., Kalamazoo, Michigan on February 18 and March 4, 1998
- Age at study initiation: adult animals (14-15 weeks)
- Weight at study initiation: 2013 - 2562 g
- Fasting period before study: not reported
- Housing: during acclimation and throughout the study, the animals were individually housed in suspended, stainless steel cages.
- Diet (e.g. ad libitum): High Fiber Rabbit Diet #7015 (Harlan Teklad)
- Water (e.g. ad libitum): tap water
- Acclimation period: at least 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16-22°C
- Humidity (%): 50±20%
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: 180 cm2
- % coverage: occlusive
- Type of wrap if used: the area of application was covered with a zl-ply 9.5-cm x 19-cm gauze pateh secured with paper tape and overwrapped with Saran Wrap<0 and Elastoplast® tape

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: after the 24-hour exposure period

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): the amount of test material applied to the test site in a thin and uniform layer was approximately 0.006 g/cm2 (500 mg/kg dose level) to 0.04 g/cm2 (3000 mg/kg dose level).
Duration of exposure:
24 hours (at the end of the 24-hour exposure period, the restraining collars and bandages were removed. Any residual test material was then removed from the test sites using water and disposable paper towels)
Doses:
500, 1000 and 3000 mg/kg bw
No. of animals per sex per dose:
5 (except the 3000 mg/kg dose group, where the treatment was interrupted for humane reasons, after 3 males were treated)
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 ay (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 1 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 ere discarded and only those tissues with lesions were collected for possible histopathological evaluation.
- Other: the initial dermal irritation reading was made 30 minutes after removal of the test material according to the Draize technique (recorded as the Day 1 score). Subsequent readings of dermal irritation were made on Days 3, 7, 10, and 14.
Statistics:
For statistical purposes in this study, the animal sacrificed in a moribund condition was considered to have died due to the test material. Using this information, the estimated LD50 value for males was 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 levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 1 000 - <= 1 510 mg/kg bw
Remarks on result:
other: see below
Mortality:
A summary of the observed mortality along with the male LD50 value and 95% confidence limits are in Table 1. One male animal treated at 1000 mg/kg was sacrificed in a moribund condition on Day 1 and is counted as having died on study. All three males treated at 3000 mg/kg were found dead within 1 day of test material administration. No other mortality was observed during the study. Based on the mortality observed in the study (considering the animal which was sacrificed in a moribund condition as having died on study), the estimated dermal LD50 value in male 6 rabbits was determined to be 1510 mg/kg. The female LD50 value is estimated as being greater than 1000 mg/kg.
Clinical signs:
All animals treated at 500 mg/kg appeared normal throughout the study with the exception that one animal vocalized after dose administration. Clinical signs of toxicity observed in all five males and three females treated at 1000 mg/kg included decreased food consumption, hypoactivity, staggered gait, prostration, dyspnea, few feces, and convulsions. Three animals vocalized after dose administration. One female treated at this dose level appeared normal throughout the study. The surviving animals treated at 1000 mg/kg that exhibited clinical signs returned to a normal appearance by Day 6 after treatment. The incidence and persistence of clinical signs were less in the females treated at 1000 mg/kg than in the males treated at this dose level. Clinical signs of toxicity observed in the three males treated at the 3000 mg/kg dose level prior to death included hypoactivity, staggered gait, and vocalization after dose administration. One of these animals also had a cut toe nail (an incidental finding).
Body weight:
Individual and mean body weights and body weight gains are in Table 2. Two males and all five females treated at 500 mg/kg exhibited weight losses of 8 to 23 g during the first week. Recovery from these weight losses was noted during the second week. Animals treated at 1000 mg/kg and surviving to the end of the observation period exhibited body weight gain during the study with the exception of one male and three females which exhibited weight losses of 22 to 78 g during the first week. These animals also exhibited weight gains during the second week of the study. The body weight losses were probably associated with the severe dermal irritation/injury observed in these animals.
Gross pathology:
At necropsy, the treated skin of each animal was observed to be variable dark-brown or red, with or without crusted areas. The treated skin was also thickened in some animals. The underlying muscle in some animals was also dark-brown or tan. These findings are attributed to the irritation/injury caused by the test material.
Other findings:
- Other observations: dermal irritation (based on the most severe score for each animal at any time point) at the 500 mg/kg dose level consisted of severe erythema, slight to moderate edema, and moderate to marked atonia and coriaceousness. Dermal irritation at the 1000 mg/kg dose level consisted of severe erythema, slight edema, marked atonia and coriaceousness. Eschar and possible necrotic areas were also observed at both dose levels. Severe dermal irritation/injury continued to be present in all animals at the Day 14 observation.

Any other information on results incl. tables

Table 1: Mortality Summary

 

Dose level (mg/kg)

Mortality results (number died or sacrificed/number dosed*)

Male

Female

500

0/5

0/5

1000

1/5 (days 1)

0/5

3000

3/3 (day 1)

-

* Number of animals found dead or sacrificed on the indicated day

 

Table 2: Mean body weights / Body weight gains (g)

 

Treatment group (mg/kg bw)

Sex

Mean body weights / Body weight gains (g)

Day 0

Day 7

Day 14

Weight

Gain*

Weight

Gain*

 

Male

2182

2199

17

2369

187

 

Female

2418

2200

-17

2381

163

 

Male

2409

2384

13

2441

70

 

Female

2403

2383

-20

2477

73

 

Male

2181

-

-

-

-

* Gain from Day 0 body weight

Applicant's summary and conclusion