1,1-dimethylheptanethiol

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a dermal sensitisation study, the skin sensitising potential of 1,1-dimethylheptanethiol was evaluated using Dunkin-Hartley guinea-pigs (5/sex – control; 10/sex - treatment) using the method of Magnusson and Kligman. The sensitisation potential of the test substance was evaluated after a 10-day induction period during which time the animals were treated with paraffin oil (control group) or the test substance (treated group). On day 1, in presence of Freund's complete adjuvant, 0.1 ml of the test substance at a concentration of 1% (w/w) in the vehicle was administered by intradermal route. On day 8, 0.5 ml of the test substance in its original form was applied by cutaneous route during 48 hours by means of an occlusive dressing. After a period of 12 days without treatment, a challenge cutaneous application of 0.5 ml of the vehicle (left flank) and 0.5 ml of the test substance at a concentration of 75% (w/w) in the vehicle (right flank) was administered to all animals. The test substance and the vehicle were prepared on a dry gauze pad then applied to the skin and held in place for 24 hours by means of an occlusive dressing. Cutaneous reactions on the challenge application sites were then evaluated 24 and 48 hours after removal of the dressing. After the final scoring period, the animals were killed and cutaneous samples were taken from the challenge application sites from the animals. The sensitivity of the guinea-pigs in C.I.T. experimental conditions was checked in a recent study with a positive sensitiser: 2,4-dinitrochlorobenzene. During induction period the test substance was applied at 0.1% (day 1) and 5% (day 8) concentrations. At cutaneous challenge application, 1% (w/w) was tested on the right flank.

 

No treatment-related clinical signs or mortality were noted during the study. Well-defined erythema was observed in 2/19 animals 24 and 48 hours after removal of the dressing. No effects of the treatment were noted in the control group. The guinea-pigs which were used in a recent study showed a satisfactory sensitisation response in 95% animals using a positive sensitiser (2,4-DNCB).

1,1-dimethylheptanethiol was considered to be weakly sensitising to the skin of guinea pigs.

Migrated from Short description of key information:
1,1-dimethylheptanethiol was observed to be weakly sensitising (effects observed in 10% of animals) to the skin of guinea pigs.

Respiratory sensitisation

Endpoint conclusion

Additional information:

No respiratory sensitisation data are available for 1,1-dimethylheptanethiol.

Migrated from Short description of key information:
No respiratory sensitisation data are available for 1,1-dimethylheptanethiol.

Justification for classification or non-classification

1,1-dimethylheptanethiol does not meet the criteria for classification and labelling as a skin sensitiser as defined by EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.