Sodium 2-mercaptoethanolate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 2-mercaptoethanolate

EC Number:

253-523-3

EC Name:

Sodium 2-mercaptoethanolate

Cas Number:

37482-11-4

Molecular formula:

C2H6OS.Na

IUPAC Name:

sodium 2-sulfanylethan-1-olate

Test material form:

liquid

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Upon their arrival at the laboratory the animals were acclimatized to the experimental environment for at least 5 days before treatment, during which time they were observed daily.
On the day of treatment, the animals were approximately 6 weeks old and had a mean body weight of 175 ± 4 g for the males and 150 ± 5 g for the females. They were identified individually by earmarks or earnotches.
During the acclimatization period and throughout the study, the animals were kept in a conventional air-conditioned animal room. The ambient conditions were as follows : Temperature: 22 ± 3°C, relative humidity: 50 ± 20%, light/dark cycle: 12 hours of light/12 hours of dark.
The air was non-recycled and filtered.
The animals were housed in groups of 4 to 7 animals of the same sex during the acclimatization period and groups of 5 animals of the same sex during the study. They were housed in polycarbonate cages (48. x 27 x 20 cm) covered with a stainless steel lid containing food and a water bottle. Sifted and dusted sawdust was provided as litter. An analysis of the potential residues and major contaminants was performed periodically.
During the study, the animals were fed ad libitum (except during fasting) with a certified pelleted diet. An analysis of the diet for quality and major contaminants (pesticides, heavy metals, mycotoxins, etc.) was performed by the supplier and given for each batch.
During the study, the animals had free access to tap water filtered by a 0.22 micron filter membrane and contained in water bottles. Bacteriological and chemical analyses of the water and detection of major contaminants (pesticides, heavy metals and nitrosamines) are made periodically.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The day before treatment, the animals were fasted for a period of approximately 18 hours prior to administration of the test substance. They received food 4 hours after treatment.
As the test substance was supposed to be toxic, the study began by a preliminary -assay performed on a reduced number of animals in order to define the approximate dose levels to be administered for the evaluation of the LD50. The results of this preliminary test (which are not mentioned in this report) enabled to constitute 3 groups of 10 animals (5 males and 5 females in each).
The test substance was administered in a single dose by oral route using a gavage cannula fitted with a stainless steel round-shaped probe fitted to a glass syringe.

Doses:

86, 150 and 250 mg/kg

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

The animals were observed frequently after administration of the test substance and at least once a day for 14 days in order to determine the reversibility or irreversibility of any clinical signs. The appearance or disappearance of any clinical signs was recorded for each animal.
The animals were checked frequently for mortality just after administration of the test substance and at least twice a day during the 14-day observation period. The time of death was recorded individually, in terms of hours or days after administration of the test substance.
The animals were individually weighed just before administration of the test substance and then on days 5, 8 and 15. The body weight gain of the treated animals was compared to a reference curve of control animals with the same initial weight.
A necropsy was performed on the animals that died during the study. On the 15th day, the surviving animals were sacrificed by C02 inhalation in excess and a necropsy was performed. After opening the thoracic and abdominal cavities, a macroscopic examination of the main organs was performed: digestive tract, heart, kidneys, liver, lungs, pancreas, spleen and any other organ with obvious abnormalities.
Due to the absence of macroscopic lesions, no organ samples were taken and no histological examination was performed.

Statistics:

The LD50 was calculated according to Probit's method. Confidence interval calculated by Fieller's method (1944).

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

98 mg/kg bw

Based on:

act. ingr.

95% CL:

32 - 135

Effect levels 2

Sex:

male

Dose descriptor:

LD50

Effect level:

162 mg/kg bw

Based on:

act. ingr.

Effect levels 3

Sex:

male/female

Dose descriptor:

LD50

Effect level:

131 mg/kg bw

Based on:

act. ingr.

95% CL:

98 - 168

Mortality:

Deaths were noted between 4 hours and 24 hours post-treatment. The mortality rate was 20%, 50% and 100% in rats at 86, 150 and 250 mg/kg respectively. The test substance was slightly less toxic in males compared to females.

Clinical signs:

A slight to marked decrease in spontaneous activity was observed during the 24 hours post-dosing. Sedation or hypoactivity appeared from 2 hours post-treatment at 86 and 150 mg/kg and from 1 hour post-treatment at 250 mg/kg. The clinical signs had reversed by day 3 at 86 and 150 mg/kg.

Body weight:

The body weight gain of the surviving animals was not affected by the treatment.

Gross pathology:

Macroscopic post-mortem examination of the main organs of the animals found dead during the study or sacrificed at the end of the study revealed no abnormalities .

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria