Thioacetic acid

Endpoint summary

Description of key information

The acute oral LD50 of THIOACETIC ACID was comprised between 200 and  350mg/kg, in female rats. Hypoactivity or sedation, piloerection,  dyspnea, lateral recumbency, tonic-clonic convulsions and hypersalivation  were the clinical signs observed prior to death. The dermal LD0 of THIOACETIC ACID is equal to or higher than 2000 mg/kg in rats. No  signs of toxicity were observed at this dose.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

discriminating dose

Value:

200 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Additional information

Oral route

The acute oral toxicity of the THIOACETIC ACID was evaluated in rats according to OECD (No. 401, 24th February 1987) and EC (92/69/EEC, B.l, 31st July 1992) guidelines. The study was conducted  in compliance with the principles of Good  Laboratory Practice Regulations. The test substance was administered by oral route (gavage) to groups of five male or five female fasted Sprague-Dawley rats. The test substance was prepared in corn oil and administered to the animals under a volume of 10 ml/kg. The study design was as follows:

 

Dose (mg/kg)	Vehicle	Volume (ml/kg)	Male	Female
200	corn oil	10		5
350	corn oil	10		5
500	corn oil	10		5
1000	corn oil	10	5

 

Clinical signs, mortality and body weight gain were checked for a period of up to 14 days following the single administration of the test substance. All animals were subjected to necropsy.

At the 200 mg/kg dose-level, no clinical signs and no mortality were recorded. At the 350, 500 and 1000 mg/kg dose-levels, all animals died within 24 hours following treatment. Hypoactivity or sedation, piloerection, dyspnea, lateral recumbency, tonic-clonic convulsions and hypersalivation were the clinical signs observed prior to death. The body weight gain of the surviving animals given 200 mg/kg was not affected by treatment with the test substance. At necropsy, a whitish coloration of the stomach and intestines was noted in the animals given 1000 mg/kg. No apparent abnormalities were observed in the other animals. The oral LD50 of the test substance THIOACETIC ACID is comprised between 200 and 350 mg/kg, in female rats.

Dermal route

The acute dermal toxicity of THIOACETIC ACID was evaluated in rats according to OECD (No. 402, 24th February 1987) and EC (92/69/EEC, B.3, 31 st July 1992) guidelines. The study was conducted in compliance with the principles of Good Laboratory Practice Regulations. The test substance was applied to the skin of one group of ten Sprague-Dawley rats (five males and five females). The application was performed with the undiluted test substance at the dose of 2000 mg/kg, taking into consideration that its specific gravity was 1.064. 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 substance.All animals were subjected to necropsy.No death occurred at 2000 mg/kg. The general behaviour and overall body weight gain of the animals were not affected by treatment with the test substance. No cutaneous reactions were observed.No apparent abnormalities were observed at necropsy in all the animals.Under these experimental conditions, the dermal LD₀of THIOACETIC ACID is equal to or higher than 2000 mg/kg in rats. No signs of toxicity were observed at this dose.

Justification for selection of acute toxicity – oral endpoint
Key study

Justification for selection of acute toxicity – dermal endpoint
Key study

Justification for classification or non-classification

Acute oral toxicity:

The oral LD₅₀of thioacetic acid was higher than 200 mg/kg and lower than 350 mg/kg in rats. In accordance with Regulation (EC) No 1272/2008, thioacetic acid shall be classified as Acute Tox. 3 (Hazard statement: H301; Toxic if swallowed) and in accordance with Annex VI of Commission Directive 2001/59/EC, tioacetic acid shall be classified as being harmful if swallowed (R22).

Acute inhalation toxicity:

Data lacking.

Acute dermal toxicity:

The percutaneous LD₀of ioacetic acid was greater than 2000 mg/kg in rats. On this basis and in accordance with Regulation (EC) No 1272/2008 and in accordance with Annex VI of Commission Directive 2001/59/EC, thioacetic acid shall not be classified with respect to acute dermal toxicity.