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Administrative data

acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From March 01, 1990 to March 21, 1990
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 401 (Acute Oral Toxicity)
according to guideline
other: E. E. C directive 84/449
GLP compliance:
Test type:
standard acute method
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
2-mercaptopropionic acid
EC Number:
EC Name:
2-mercaptopropionic acid
Cas Number:
Molecular formula:
2-sulfanylpropanoic acid
Test material form:
Details on test material:
colourless clear liquid
Specific details on test material used for the study:
Purity: 99.3 %

Test animals

Details on test animals or test system and environmental conditions:
Species, strain: Ico rat OFA.SD. (IOPS Caw),
Supplier: Iffa-Credo (69592 L'Arbresle Cedex - France),
Age: young adults between 5 and 7 weeks old.
Weight at the start of treatment (main study): from 123 g to 173 g (the individual weighs for each sex varied by no more than 20 % of the mean weight of the animals).

Environmental conditions:
Cages housed by sex and in groups of 5·(or 2 for the preliminary study), in type FI polycarbonate cages (interior dimensions 305 x 180 x 184 mm) for the preliminary study and in type MI (interior dimensions 365 x 225 x 180 mm) for the main study.
Air changes: at least 10 per hour
Temperature: 22 ± 3 °C
Humidity: 30 to 70 %
Lighting: artificial, 12 hours out of 24.
Hygiene: bedding changed once a week; cages changed for each study.
Diet: complete pelleted rat-mouse maintenance diet ad libitum (U.A.R., formula A.04 CR - U.A.R.).
Water: softened and filtered (0.6 µm) mains drinking water ad libitum. Bacteriological and chemical analyses checked twice a year.
Acclimatisation period: 8 days before the start of treatment.
Clinical examinations: at reception then before the start of treatment to ensure that only healthy animals are included in the study.
Identification of animals: perforation of ear pinna before the start of treatment.

Administration / exposure

Route of administration:
oral: gavage
unchanged (no vehicle)
Details on oral exposure:
Single oral administration by gestric gavage - round –ended curved stainless-steel oesophageal probe, 3 mm diameter, Perfektum.
No. of animals per sex per dose:
Preliminary study: 6 males, 6 non-pregnant females;
Main study:
control group - 5 males, 5 non-pregnant females;
groups 2 to 6 (treated) - 25 males, 25 non-pregnant females.
Control animals:
Details on study design:
Preliminary test:
3 groups each composed of 2 males and 2 females were treated, at dose levels of 504, 1008 and 2004 respectively at a volume of 0.42, 0.84 and 1.67 ml/kg of test substance as supplied. The test substance was administered after about 19 h of a water regime and received food 4 h after intubation.

Main test:
Five groups of 5 females and 5 males were dosed with at the levels of 360, 456, 564, 708 and 900 mg/kg, corresponding to
0.30, 0.38, 0.47, 0.59 and 0.75 ml/kg respectively. The control group was treated with the distilled water under the same conditions. The test article was administered once only after about 17 h and 30 min of a water regime and received food 4 h after intubation.

Following examinations were performed:
- Clinical examinations: 15 minutes after intubation, then at 1, 2 and 4 hours and then daily for 14 days.
The daily observations performed, amongst others, included changes in the skin and fur, the eyes, mucous membranes, respiratory system, circulatory system, autonomic and central nervous systems, as well as somato-motor activity and behaviour. Shivering, convulsions, salivation, diarrhoea, lethargy, sleeping and coma were noted with particular attention.
- Observation of body weight: Day -1, Days 1 (before administration of the test article), 8 and 15, as well as at the time of death from Day 2 onwards.
- Necropsy examination of all animals. The abdominal and thoracic cavities were opened and particular attention was paid to the following organs: liver, heart, kidneys and lungs.

Results and discussion

Preliminary study:
100 % mortality in all dose groups.
Effect levels
Key result
Dose descriptor:
Effect level:
730 mg/kg bw
Based on:
test mat.
95% CL:
> 651 - < 819
10 % mortality in 564 mg/kg dose group, 50 % in 708 mg/kg dose group, 80 % in 900 mg/kg dose group.
Clinical signs:
other: At at 360 mg/kg and at 456 mg/kg all animals showed subdued behaviour 15 min, 1 and 2 h after administration, some after 4 h and Day 2. At 360 mg/kg: All rats were normal on the day following treatment. At 456 mg/kg: All rats were normal on Day 3. at 564
Gross pathology:
Some animals that died during the study showed congested areas in the mucosa of the non-glandular stomach and a stenosis of the oesophagus with whitish substance. This oesophagial abnormality was also noted in some rats sacrified at the end of the study (groups 2 - 3 - 4 and 5); the other animals do not present any macroscopic abnormality.

Applicant's summary and conclusion

Interpretation of results:
Category 3 based on GHS criteria
Under the study conditions, the LD 50 of the test substance in the rat (male and female) was determined to be 730 mg/kg bw (651 - 819 mg/kg) by Bliss method and 735 mg/kg bw (641 – 844) by Litchfield & Wilcoxon's method.
Executive summary:

A study was conducted to determine the potential toxic effect of the test substance when administered as a single oral dose to Wistar rats according to OECD Guideline 401. The test substance was administered once only, as supplied and at the dose levels of 360, 456, 564, 708 and 900 mg/kg bw, by the oral route (gastric gavage), in the Sprague-Dawley rat (5 males and 5 females per group). This study was performed in comparison with a control group of 10 rats of both sexes treated with the distilled water under the same conditions. Mortality and abnormal clinical signs were noted 15 min after intubation, then at 1, 2 and 4 h, and then daily for the 14 d study period. All the animals were weighed the day before treatment (Day-1), immediately before administration of the test substance (Day-1), on Days 8 and 15, as well as at time of death from Day-2 onwards. A necropsy was performed for all the animals dead during the study and for all surviving rats after the 14 d study period and the final observation (Day-15). Under the study conditions, the LD 50 of the test substance in the rat (male and female) was determined to be 730 mg/kg bw (651 - 819 mg/kg) by Bliss method and 735 mg/kg bw (641 – 844) by the Litchfield & Wilcoxon’s method (Lheritier, 1990).