NTP Toxicology And Carcinogenesis Studies Of C.I. Acid Orange 3 In F344/N Rats And B6C3F1 Mice

The study investigated the toxicology and carcinogenicity of C.I. Acid Orange 3, a dye used in semipermanent hair coloring, in F344/N rats and B6C3F1 mice. Over 2 years, the dye was administered by gavage in corn oil to groups of 50 animals per sex and species. In rats, there was clear evidence of carcinogenic activity in female rats, as indicated by transitional cell carcinomas of the kidney at the highest dose of 750 mg/kg, along with nonneoplastic kidney lesions. No carcinogenic activity was observed in male rats or in male and female mice. The study also noted nonneoplastic kidney lesions in both species and sexes. The dye was mutagenic in certain strains of Salmonella typhimurium. The study concluded that C.I. Acid Orange 3 posed a carcinogenic risk to female rats but not to male rats or mice.