Dodecane-1-thiol

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The key study comes from 2012 LLNA evaluation. The test material was administered to 10 groups of 4 CBA/J female mice by topical route to the dorsal surface of both ears at constant dose volume of 25µL. The first group received concentrations of 0.1, 0.25, 0.5, 1, and 2.5% by topical route. These concentrations were not sufficient to determine a dose-level responsible of irritation, therefore in the five following groups were tested concentrations of 0.2,0.4, 0.8, 1.6, and 3.2%. The result of the second assay showed that the stimulation index values relative to concentrations 1.6 (SI=15.99) and 3.2% (SI=21.46) were exceeding the positive control group (SI=10.96). No clinical signs and mortality were observed. The conclusion of the study is that the test item, n-dodecyl mercaptan, induced delayed contact hypersesitivity in the murine Local Lymph Assay, in a consistent and dose related manner. This suggests that 1 -dodecanethiol is a slight sensitiser.

In a second sensitization study (Shapiro, 1988; Klimisch score = 1), male Hartley guinea pigs (16/dose) were dermally exposed to 0.4 or 0.5 mL dodecane-1-thiol for a period of 6 hours for a total of 6 doses. Due to irritation observed in the first 3 induction doses, the concentration of the test material was reduced from 50% to 25% (v/v in ethyl alcohol) for doses 4 and 5, and to 12.5% for the last dose. Following a 15-day rest period, guinea pigs were subjected to 2 challenge doses of dodecane-1 -thiol at concentrations of 1% or 3% (v/v in ethyl alcohol). Dinitrochlorobenzene (0.08%) in 95% ethyl alcohol was employed as the positive control and naïve controls were also utilized in the study design. Animals were scored for sensitization 24 and 48 hours post challenge. Apart from skin irritation, all animals appeared active and healthy during the test period. Irritation was also noted at all test and naive sites 24 and 48 hours after challenge with 3% test product in 95% ethyl alcohol and at most test and naive sites 24 hours after challenge with a 1% solution of test product. These findings suggest that the test material is a primary skin irritant. Similar responses were observed in the sensitized guinea pigs and naïve control animals. This suggests that the post-challenge erythema is more likely a primary skin irritation rather than a sensitization response and the test product was therefore not considered to be a contact sensitizer.

 

Based on the data available, dodecane-1-thiol is considered to be a slight skin sensitiser.

Migrated from Short description of key information:
The key study showed that n-dodecyl mercaptan, induced delayed contact hypersesitivity in the murine Local Lymph Assay suggesting that the test material is a slight sensitiser. In contrast, a second study conducted on guinea pig showed that Dodecane-1-thiol was not considered to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion

Additional information:

Migrated from Short description of key information:
There are no data available on the respiratory sensitisation potential of dodecane-1-thiol.

Justification for classification or non-classification

Based on key data available for dodecane-1-thiol and taking into consideration the weight of evidence from structurally similar thiols, dodecane-1 -thiol does meet the classification requirements for sensitisation under CLP and DSD.