Toxicity Profile for Toluene-2,5-diamine (and its salts) (1995)

Abstract

A serious blood disorder (aplastic anaemia) has been reported in individuals using a hair dye containing toluene-2,5-diamine (2,5-TDA) or its sulphate. Sensitization reactions to 2,5-TDA or its salts have been described, particularly amongst hairdressers and hair-dye users. 2,5-TDA has caused eye inflammation in one individual whilst a solution of the sulphate was essentially non-irritating to the eyes of rabbits (when rinsed) and guinea-pigs, but irritating to the skin of rabbits. The acute toxicity of the sulphate salt to rats was high when administered orally or by intraperitoneal injection.

No evidence of chromosomal effects was seen in the blood of volunteers who repeatedly dyed their hair with 2,5-TDA-containing formulations. A range of genotoxicity screening assays in rodents gave generally negative results with 2,5-TDA and its sulphate. However, positive results were obtained with 2,5-TDA and its salts in mammalian cells in culture and in Ames bacterial tests. A long-term study in which rats and mice were fed 2,5-TDA sulphate provided no convincing evidence of carcinogenicity.

Reproductive effects amongst small numbers of workers exposed to an unspecified isomer of TDA and to dinitrotoluene were not confirmed by subsequent studies in larger groups of exposed workers. 2,5-TDA salts given to mice by injection or by stomach tube had a foetotoxic effect and possibly also caused malformations. Foetotoxicity was also reported in rats receiving 2,5-TDA sulphate orally during pregnancy, but only at a maternally toxic dose.