1,1-dimethylheptanethiol

Endpoint summary

Description of key information

Key data were identified to evaluate the acute oral, dermal, and inhalation toxicity potential of 1,1-dimethylheptanethiol. The key parameters are discussed below: 
• Acute oral LD50: 5550 mg/kg bw 
• Acute dermal LD50: >2000 mg/kg bw
• Acute inhalation LC50: >7.04 mg/L

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 550 mg/kg bw

Additional information

Acute Oral Toxicity

One key acute study in the rat was identified to evaluate the oral toxicity potential of 1,1-dimethylheptanethiol.

In a key acute oral toxicity study (Latven, 1977a; Klimisch score = 2), groups of male WBS/W rats (5/dose) were orally administered (via gavage) a single dose of 1,1-dimethylheptanethiol at 3536, 5000, 7071, or 10,000 mg/kg bw. Animals were subsequently observed for a period of 7 days.

 

Motor inactivity, disorientation, and lack of co-ordination were observed at 24 and 48 hours for all groups. Body weight losses were observed for several days among survivors, but recovery was observed 5 or 6 days after treatment. Autopsies revealed probable hepatic and renal pathology. 40% mortality was observed at 5000 mg/kg; 80% at 7071 mg/kg; and100% mortality was observed in rats that received 1,1-dimethylheptanethiol at 10,000 mg/kg bw. The oral LD₅₀ in male rats was determined to be 5550 mg/kg.

Acute Inhalation Toxicity

Two key acute studies in the rat were identified to evaluate the inhalation toxicity potential of 1,1-dimethylheptanethiol.

In a key acute inhalation toxicity study (Collins, 1987; Klimisch score = 1), Crl:CD(SD)BR strain rats (5/sex) were exposed via inhalation (head only) to 1,1-dimethylheptanethiol for 4.5 hours at a concentration of 7.04 mg/L. Animals were subsequently observed for a period of 14 days. No mortality was observed in either male or female rats through the course of the study. Marked clinical signs of pilo-erection, ataxia, transient salivation and wet fur were observed for all treated animals. These signs were not apparent in control animals. No treatment-related effects on body weight were observed in either male or female rats. No gross or histopathological signs of specific organ toxicity were observed in any of the treated animals. Based on the lack of treatment-related signs of clinical toxicity, the acute inhalation LC₅₀ for 1,1-dimethylheptanethiol was determined to be >7.04 mg/L (7041 mg/m³ or 1074 ppm).

In a second key acute inhalation toxicity study (Hardy and Jackson, 1987; Klimisch socre = 1), young adult Sprague-Dawley rats (5/sex/dose) were exposed to 1,1-dimethylheptanethiol vapour via the inhalation route (whole body) at a concentration of 1.97 mg/L for a period of 4 hours.Animals were subsequently observed for a period of 14 days. No mortality was observed in either male or female rats exposed to 1,1-dimethylheptanethiol. Signs observed during exposure included closing or partial closing of the eyes, disturbances to the respiratory pattern, and adoption of a hunched body posture. These effects were attributed to the irritant nature of the vapour. Immediately subsequent to exposure, all rats in the exposed group were ataxic and had a slow respiratory pattern. All rats seemed normal in behavior and appearance after Day 1 of the post-exposure observation period. No adverse treatment-related effects on bodyweight gain were observed through the study period and macroscopic pathology did not reveal any remarkable findings. Based on the lack of adverse signs of toxicity, the acute inhalation LC₅₀ for 1,1-dimethylheptanethiol was determined to be >1.97 mg/L (1970 mg/m³ or 300 ppm) in rats.

Acute Dermal Toxicity

One key acute study in the rat was identified to evaluate the dermal toxicity potential of 1,1-dimethylheptanethiol.

In an acute dermal toxicity study (Latven, 1977b; Klimisch score = 2), 6 male WBS/W rats were dermally administered a single dose of 1,1-dimethylheptanethiol at 2000 mg/kg bw. A pre-fitted occlusive sleeve was then placed on each animal and remained in place for 24 hours. The animals were subsequently observed for a period of 7 days.

 

None of the animals exhibited any clinical symptoms and no mortality was observed through the study period. Some loss in body weight was observed but had recovered one day later. Based on the lack of observed adverse toxicity effects, the acute dermal LD₅₀ for 1,1 -dimethylheptanethiol was determined to be >2000 mg/kg bw.

Justification for classification or non-classification

1,1-dimethylheptanethiol does not meet the criteria for classification as an acute oral toxicant under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.

1,1-dimethylheptanethiol does not meet the criteria for classification as an acute dermal toxicant under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.

 

1,1-dimethylheptanethiol does not meet the criteria for classification as an acute inhalation toxicant under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.