Sodium mercaptoacetate

Endpoint summary

Description of key information

NaTG is toxic by ingestion and harmful in contact with skin.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 31 August to 01 December 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

ANIMALS
- Source: RCC, Ltd, Biotechnology & Animal breeding division,  Wölferstrasse, 4 CH-4414 Füllinsdorf , Switzerland.
- Age: 8-10 weeks
- Weight:  217.1-234.7 g (M), 158.9-181.9 g (F)
- Acclimatization: 1 week
- Housing: 3 per sex
- Diet: ad libitum Pelleted standard Kliba 3433, batch n° 03/00 and 04/00,  rat maintenance diet (Provimi Kliba AG, CH-4303 Kaiseraugst)
- Water: ad libitum tap water

CONDITIONS:
- Air changes: 10-15/hour
- Temperature: 21-23.5 °C
- Relative Humidity: 36-57%
- Light-Dark cycle: 12/12

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The animals received a single dose of the test item on a 200, 50 or 25 mg/kg bw by oral gavage following fasting for approx. 17 hours, but with free access to water. Food was provided again 3 hours after dosing.

Doses:

25, 50 and 200 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

Animals were observed once daily during the acclimatization phase and then 1, 2, 3 and 5 hours after administration on day 1 and twice daily for surviving animals during days 2-15. Surviving animals were weighted on day 1, 8 and 15. All abnormalities and clinical signs were recorded. All animals were necropsied and examined macroscopically.

Statistics:

None

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 50 - <= 200 mg/kg bw

Based on:

test mat.

Mortality:

All males and females treated at 25 and 50 mg/kg survived until scheduled  necropsy. Two out of 3 females treated at 200 mg/kg died on day 1. The following animals were treated and percentage mortality was observed:                          
Males         Females
Group 1 (200 mg/kg)                 66%        
Group 2 (50 mg/kg)                 0%
Group 3 (50 mg/kg)        0%
Group 4 (25 mg/kg)                 0%
Group 5 (25 mg/kg)         0%

Clinical signs:

other: No clinical signs were observed during the observation period in all 50  mg/kg treated males and females and all 25 mg/kg treated females. Slightly ruffed fur was observed in all 200 mg/kg treated females from 1  to 3 hours (2 females) or from 1 or 5 ho

Gross pathology:

A distended stomach with gas was observed at the unscheduled necropsy in  two females treated at 200 mg/kg. No macroscopic findings were observed  at the other scheduled necropsy.

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The median lethal dose is between 50 and 200 mg/kg in rat after a single oral administration in both sexes.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

50 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7-Mar-2003 - 19-Sep-2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

French Republic, Prime Minister, Interministerial Group on Chemicals (GIPC)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Breeder: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: approximately 9 weeks
- Weight at study initiation: 290 ± 7 g for the males and 228 ± 6 g for the females
- Water and food: ad libitum
- Acclimation period: at least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 30 to 70
- Ventilation: approximately 12 cycles/hour of filtered, non-recycled air.

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

- Area of exposure: a dorsal area of the skin (approximately 5 cm x 6 cm for the females and 5 cm x 7 cm for the males)
- % coverage: approximately 10%
- Type of wrap if used: hydrophilic gauze pad held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage.

Duration of exposure:

24 h

Doses:

A single dose of 2000 mg/kg of the test item in its original form was placed on a hydrophilic gauze pad (pre-moistened with 2 mL of PEG 400) and then applied to the clipped area of the skin.

No. of animals per sex per dose:

5

Control animals:

yes, concurrent no treatment

Sex:

male

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 1 000 - <= 2 000 mg/kg bw

Based on:

test mat.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 798 - <= 1 596 mg/kg bw

Based on:

act. ingr.

Mortality:

At the 2000 mg/kg dose-level, all females were found dead or died on day 2. No clinical signs were observed prior to death in four of them and the last one was in coma prior to death.

Clinical signs:

other: At the 2000 mg/kg dose-level, in males, no clinical signs were noted. Dryness of the skin was recorded in 3/5 animals on day 3; it persisted, together with crusts, in one of them until day 7. At 1000 mg/kg, no clinical signs were recorded. A very slight o

Gross pathology:

Macroscopic examination of the main organs of the animals revealed no apparent abnormalities.

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

Under the experimental conditions, the dermal LD50 of NaTG is higher than 2000 mg/kg in male rats and is between 1000 and 2000 mg/kg in female rats.

Executive summary:

The test item was applied to the skin of one group of ten Sprague-Dawley rats (five males and five females).

The application was performed with the test item in its original form at the dose-level of 2000 mg/kg. Water was used to moisten the gauze pad and ensure a good contact with the skin. The test site was then covered by a semi-occlusive dressing for 24 hours.

Clinical signs, mortality and body weight gain were checked for a period of 14 days following the single application of the test item.

At the 2000 mg/kg dose-level, all females were found dead or died on day 2. No clinical signs were observed prior to death in four of them and the last one was in coma prior to death.

In males, no clinical signs and no mortality occurred. Dryness of the skin was recorded in 3/5 animals on day 3; it persisted, together with crusts, in one of them until day 7.

At 1000 mg/kg, no clinical signs and no mortality occurred. A very slight or well-defined erythema, together with dryness of the skin in 3/5 animals, was observed in all females from day 4 up to day 8; some of these reactions persisted in 3/5 animals until day 10, 11 or 13.

A reduced body weight gain was seen in 4/5 females receiving the test item at the dose-level of 1000 mg/kg between day 1 and day 8. The body weight gain of the other animals was similar to that of CIT historical control animals.

All animals were subjected to necropsy, but no apparent abnormalities were observed in any animal.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

1 000 mg/kg bw

Quality of whole database:

LD50 determined with NaTG (LD50 is >1000 mg/kg bw for female rats.

Additional information

Thioglycolic acid and its salts are toxic by oral administration. When expressed as thioglycolate anion, the LD₅₀values of thioglycolic acid and its salts are quite accurately in the same dose range.

Justification for selection of acute toxicity – oral endpoint
LD50 determined via ATC method with NaTG

Justification for classification or non-classification

Based on acute oral and dermal toxicity data in rats.

Classification:

DSD: T, R25. Toxic if swallowed. Xn, R21. Harmful in contact with skin.

EU-GHS: Acute tox cat. 3. H301. Toxic if swallowed. Acute tox cat. 4. H312: Harmful in contact with skin.