Zirconium di(acetate) oxide

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A GLP-compliant OECD guideline 406 study (Magnusson-Kligman maximisation) test with guinea pigs was available (BASF AG, 1987). A group of 20 female Dunkin-Hartley guinea pigs was induced intradermally with0.1 ml Freund's adjuvant without the test substance emulsified with water (ratio 1:1), 0.1 mL of 25% dilution in water of the test substance and 0.1 mL Freund's adjuvant/water (1:1) with test substance. One week later the animals were induced epicutaneously with a single 48 hours application of the unchanged test substance under occlusive conditions. Two control groups were induced intradermally with the same injections, but without the test substance. No epicutaneous induction was performed, since the test substance was applied unchanged and no solvent was used. Approximately 14 days after epicutaneous induction, the animals of the test group and of the first control group were challenged at the untreated site epicutaneously for 24 hours with the unchanged substance under occlusive conditions. The animals of the second group remained untreated. The readings of the skin reactions were performed ca. 24, 48 and 72 hours after the beginning of application. One week later a rechallenge was performed, in which animals of all groups were treated with the test substance for 24 hours under occlusive conditions and the readings were performed after 24, 48 and 72 hours.

After intradermal induction distinct erythema and edema were observed at the injection sites of the control animals and the test animals which were applied with Freund's adjuvant/water (1:1). The test substance formulation in water or Freund's adjuvant/water (1:1) caused necrotic skin changes and distinct edema in the test animals. No skin changes were observed in the control animals which were applied with solvent. After percutaneous induction, necrotic skin changes caused by the intradermal induction were observed in addition to distinct edema.

The percutaneous challenges with the unchanged test substance did not cause any skin changes either in the test group or in the control groups. The scores were 0 at all time points in all animals. Based on the results of the study, the substance is concluded to be not sensitising to the skin.

Migrated from Short description of key information:
Based on the results of a GLP-compliant OECD guideline 406 (Magnusson-Kligman assay) study, zirconium di(acetate) oxide is not considered a skin sensitiser.

Justification for classification or non-classification

Based on the negative results in the GLP-compliant OECD Guideline 406 study (Magnusson-Kligman assay), classification of zirconium di(acetate) oxide as a skin sensitiser according to EU Directive 67/548 and EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 is not warranted.