Octabenzone

Endpoint summary

Description of key information

Three valid guinea pig maximization tests are available with commercial material from two different suppliers. The material from one supplier is not sensitizing whereas the material from the other supplier is moderately sensitizing.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Three valid guinea pig maximization tests are available with commercial material from two different suppliers. The material from one supplier is not sensitizing whereas the material from the other supplier is moderately sensitizing. The different results cannot be explained by differences in experimental procedures or choice of vehicle.

The test item was reported to be non sensitizing in a guinea pig maximization test performed under GLP and following the procedure of OECD testing guideline 406. Male Dunkin Hartley guinea pigs were used. The tested sample was a commercial product with a purity of > 98.5%. Concentrations were 5% in arachis oil for intradermal induction and 50% in arachis oil for epidermal induction. The epidermal induction treatment caused mostly grade 2 erythema at the 1h reading and mostly grade 1 erythema at the 24h reading. After challenge with either 25% or 50% in arachis oil, none of the twenty animals showed skin reactions at the 24h or 48h reading.

The material from the second supplier was found sensitizing in a guinea pig maximization test performed under GLP and following the procedure of OECD testing guideline 406. Male Pirbright White guinea pigs were used. The tested sample was a commercial product with a purity of > 99.5%. Applied concentrations were 5% in arachis oil for intradermal induction, 20 % in vaseline for epidermal induction and 30% in vaseline for epidermal challenge. After challenge, 13 and 12 of 20 animals showed skin reactions after 24 and 48h, respectively.

The test item as furthermore reported to be sensitizing in a second guinea pig maximization test performed under GLP and following the procedure of OECD testing guideline 406. Male and female Himalayan spotted guinea pigs were used. The tested sample was a commercial product and details on purity are not given in the report. Concentrations were 15% in PEG 300 for intradermal induction, 40 % in PEG for epidermal induction and 40% in PEG 300 for epidermal challenge. Prior to epidermal induction, the skin was treated with 10% sodium lauryl sulphate to induce irritation. After challenge, 7 and 7 of 9 animals showed skin reactions after 24 and 48h, respectively.

An analogue substance which carries a methyl substituent instead of an octyl substituent is known to cause skin sensitization, noting that for the analogue substance, skin penetration is better because of the lower molecuar weight.

The positive findings indicate that the test item is of moderate potency according to the EU expert group on skin sensitization. No case reports of sensitized people were found in the published literature.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is considered to be classified for skin sensitization (Category 1B) under Regulation (EC) No. 1272/2008, as amended for the eighth time in Regulation (EU) No 2016/218.