Octane-1-thiol

Endpoint summary

Description of key information

Key data were identified to evaluate the acute oral, dermal, and inhalation toxicity potential of octane-1-thiol. The key parameters are discussed below :
• Acute oral LD50: >2000 mg/kg bw 
• Acute dermal LD50: >2000 mg/kg bw
• Acute inhalation LC50: >3.1 mg/L

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

3.1 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Acute Oral Toxicity

One key acute study was identified to evaluate the acute oral toxicity potential of octane-1-thiol.

In a key acute oral toxicity study (Moon, 1981a; Klimisch score = 1), groups of fasted, albino rats (5/sex/dose) were given a single oral dose of octane-1-thiol at doses of 1680, 2100, 2688, or 3360 mg/kg bw and subsequently observed for 14 days. Mortality was observed in one animal in the 1680 mg/kg bw dose group while 3, 6, and 9 animals dies in 2100, 2688, and 3360 mg/kg bw dose groups, respectively. Treatment related clinical signs such as lacrimation, loss of activity, ruffed fur, ocular bleeding, and respiratory conditions were seen in animals that died through the study period. Gross necroscopy revealed abnormalities in the lung, liver, stomach, intestines, kidneys, gonads, and ovaries in 3 of 10 animals that were tested at the 1680 mg/kg dose level. 8 of 10 rats dosed at 2100 mg/kg bw were seen to have abnormalities in the lungs, liver, adrenal glands, stomach, spleen, kidneys, and intestines. Abnormalities in multiple organs were seen in all animals that were treated with octane-1-thiol at 2688 and 3360 mg/kg bw. Using probit analysis the oral LD₅₀ for octane-1-thiol was determined to be 2436 mg/kg bw in males and female rats.

 

In a supporting guideline (OECD 401) acute oral toxicity study (MHLW, 2004; Klimisch score = 1), groups of fasted Sprague-Dawley rats (Crj:CD(SD)IGS,SPF; 5/sex) were given a single oral dose of octane-1-thiol (CAS # 111-88-6) at doses of 0, 250, 500, 1000, 2000 mg/kg bw. The animals were subsequently observed and weighed daily for a period of 14 days. Two male and all female rats in the 2000 mg/kg bw dose group died on day 3 post-exposure. One female rat dosed at 1000 kg/mg bw also died by day 3 post-exposure. Treatment-related clinical signs of toxicity supported by observations at gross necroscopy were observed in male and female rats treated with octane-1-thiol at doses of 1000 and 2000 mg/kg bw. Gross necroscopy also revealed treatment-related effects in female rats dosed at the 500 mg/kg bw dose level. Body weights were observed to be lower in the three highest dose levels by day 2 post-exposure when compared with the corresponding controls. Based on the effects seen, the oral LD₅₀ was determined to be >2000 mg/kg bw in males and 1293 mg/kg bw (95% confidence limit; 889-1780 mg/kg) in female rats.  

 

Supporting data are available from one study conducted in rats. One acute oral toxicity study (Latven, 1958; Klimisch score = 2) reported an LD₅₀ of 2000 mg/kg bw based on mortality observed in 3 of 6 male WBS/W rats orally administered octane-1-thiol.

 

Based on the weight of evidence of key and supporting data, the acute oral LD₅₀ for octane-1-thiol was determined to be >2000 mg/kg bw.

Acute Dermal Toxicity

One key study in rabbits was identified to evaluate the acute dermal toxicity potential of octane-1-thiol.

In a key acute dermal toxicity study (Moon, 1981b; Klimisch score = 2), groups of New Zealand albino rabbits (3/sex) were dermally exposed to octane-1-thiol for 24 hours at a dose of 1680 mg/kg bw. Animals were subsequently observed for a period of 14 days. There was no mortality observed in either male or female rabbits through the study period. Erythema was observed in all animals on day 1 and persisted through day 6 of the study period. Induration that appeared on day 5 and persisted through day 14 was observed in five of the 6 animals. No treatment-related adverse effects on body weight were observed through the study period and gross necroscopy did not reveal any remarkable findings. In the absence of adverse systemic toxicity effects, the acute dermal LD₅₀ was determined to be >1680 mg/kg bw.

 

Supporting data available from a study conducted in rats (Latven, 1977; Klimisch score = 2) indicates that the LD₅₀ for octane-1-thiol is >2000 mg/kg bw in rats.

 

Based on the key data available, octane-1-thiol has a low order of toxicity via the dermal route with an LD₅₀ >2000 mg/kg bw/day.

Acute Inhalation Toxicity

One key acute study was identified to evaluate the acute inhalation toxicity potential of octane-1-thiol.

In a key acute inhalation toxicity study (Collins, 1987; Klimisch score = 2) young adult Sprague-Dawley rats (5/sex) were exposed via the inhalation route (head only) to 3.10 mg/L octane-1-thiol for 4.5 hours. Animals were subsequently observed for a period of 14 days. No treatment-related macroscopic or microscopic changes were evident through the study period. Clinical signs observed during the study were ataxia, lethargy, salivation, lachrymation, and piloerection on the day of exposure. Piloerection was also noted on the day following exposure. Based on the lack of adverse treatment-related effects, the acute inhalation LC₅₀ was determined to be >3.10 mg/L in male and female rats.

In a supporting acute inhalation toxicity study (Hardy and Jackson, 1987; Klimisch score = 1), groups of young adult Sprague-Dawley rats (5/sex) were exposed via the inhalation route (whole body) to octane-1-thiol at concentrations of 0 or 0.24 mg/L. Animals were subsequently observed for 14 days. No mortality was observed in either male or female rats following exposure to octane-1-thiol. During exposure, clinical signs such as hunched body posture and a slow, shallow respiratory pattern were observed. These were attributed to the irritant nature of the vapour. Apart from hyperactivity immediately following exposure, the rats exposed to octane-1-thiol were normal in appearance and behaviour throughout the observation period. Body weight remained unaffected through the study period and gross necroscopy revealed minimal congestion in the lungs of 2 rats exposed to octane-1-thiol. Based on the lack of significant treatment-related signs of clinical toxicity, the acute inhalation LC₅₀ was determined to be >0.24 mg/L.

Supporting data from another study (Yates, 1981; Klimisch score = 1) in rats exposed (whole-body inhalation) to vapours of octane-1-thiol at a concentration of 3.04 mg/L (508 ppm) did not show any treatment-related effects. The LC₅₀ was therefore determined to be >3.04 mg/L in this study.

 

Justification for classification or non-classification

Octane-1-thiol 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.

 

Octane-1-thiol 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.

 

Octane-1-thiol 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.