Sodium octyl sulphate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are several studies regarding skin sensitisation with C8AS Na (CAS 142-31-4) available.

The key study assessed the skin sensitizing potential of C8AS Na (CAS 142-31-4, analytical purity 32%) in a Local Lymph Node Assay similar to OECD Guideline 429 (P&G, 1992). In this study 12.5 µL of a 10, 50 and 100% aqueous solution of the test substance were topically applied on 4 consecutive days to 5 female CBA mice per dose group. 21 h after the last treatment all animals received injections with radiolabelled thymidine. Animals were sacrificed 5 h thereafter and auricular lymph nodes were removed. Single cell suspensions were prepared, washed and precipitated. The total radio counts in these precipitates were subsequently quantified by liquid scintillation spectrometry. The stimulation index in the carrier control was 1. The stimulation indices for the naive control and animals tretated with 10, 50 and 100% of the test substance were 2.4, 1.25, 2.7 and 3.1, respectively. The treatment had no significant effect on thymidine incorporation and thus the test substance showed not sensitising potential.

 

The safety under exaggerated conditions of product exposure was confirmed by 5 human repeat-insult patch tests (HRIPT) with volunteers at lower concentrations of C8AS Na (CAS 142-31-4). All HRIPT were performed with 0.4 to 0.5 mL test substance at concentrations ranging from 0.1 to 0.5% active ingredients. During the conduct of all studies the test substance was applied for 24 h under occlusive conditions to the upper arm of volunteers. This induction was performed three times a week on three consecutive weeks. After a two weeks rest period the test substance was applied at the same concentration as during the induction phase under occlusive conditions. The studies were performed with 95 to 116 volunteers aged from 17 to 70 years. None of the studies revealed any evidence of sensitisation. In one study a mild erythema was observed during the induction phase (P&G, 1994b). In another study a mild erythema was observed at 6/100 volunteers during the challenge period (P&G, 1993a). Signs of irritation during the conduct of the study were also reported in the study of P&G (1994a) however without indication when these signs occurred.

Results of the above mentioned studies show that C8AS Na (CAS 142-31-4) is not a skin sensitizer. Another alkyl sulfate, i.e. sodium lauryl sulphate (C12AS Na) is recommended as an agent to induce local irritation in a method to assess skin sensitising properties of chemicals (OECD guideline 406, Guinea Pig Maximisation Test). Therefore there is a lot of experience with sodium lauryl sulfate in sensitising studies and no evidence occurred that it shows sensitising properties. Thus, skin sensitisation by members of the alkyl sulfates is generally unlikely.

Migrated from Short description of key information:
Skin sensitisation (LLNA - OECD 429): not sensitising

Justification for selection of skin sensitisation endpoint:
Reliable study conducted similar to OECD guidelin 429

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the classification criteria of Directive 67/548/EEC and Regulation (EC) No 1272/2008 the substance does not need to be classified for skin sensitization. No data is available for respiratory sensitization.