Registration Dossier

Diss Factsheets

Toxicological information


Currently viewing:

Administrative data

Description of key information

Carcinogenicity of o-anisidine has not been investigated. But o-anisidine hydrochloride is carcinogenic in rats and mice, with its main target organ being the urinary bladder. 

Key value for chemical safety assessment

Justification for classification or non-classification

In accordance with the procedure of the EU-RAR and based on the results on carcinogenicity obtained with o-anisidine hydrochloride and the mutagenic activity of o-ansidine itself it is evident, that the submission substance has carcinogenic properties. In conclusion data are considered to be sufficient for classification as Carc 1B, H350 and Carc. Cat 2; R45 which fits to the current classification in Annex VI to Regulation (EC) No.1272/2008.

Additional information

There are no human data and no investigations in experimental animals on carcinogenicity of o-anisidine. But o-anisidine hydrochloride was found to be carcinogenic in mice and rats in a two year carcinogenicity study. The carcinogenic effect of o-anisidine hydrochloride after oral administration is probably due to o-anisidine itself, because o-anisidine hydrochloride rapidly hydrolyses to o-anisidine in vivo. In both studies the main target organ was the urinary bladder. Additionally in male rats o-anisidine hydrochloride gave rise to thyroidal tumours. The authors of the EU-RAR assume that these tumors of the thyroid "may be caused by thyroid-pituitary imbalance, leading to increases of sizeand proliferation of certain thyroid cells, in order to be able to produce enough hormone." Furthermore they concluded that o-anisidine has to be considered a genotoxic carcinogen because there is sufficient evidence that o-anisidine is mutagenic in vitro while equivocal results on genotoxicty were obtained in vivo. Additionally, an indirect mechanism cannot be ruled out for o-anisidine, since there were no indications for DNA adducts in liver and bladder of treated animals whereas an increased mutation frequency was observed in the bladder of transgenic mice.

Based on the findings mentioned above o-anisidine has been classified as carcinogenic category 2 according to Council Directive 67/548/EEC.