The anthraquinone color Disperse Blue 1 is used in many nonoxidative hair dyes, colors and rinses. In vitro dermal penetration studies using skin from miniature pigs indicate this ingredient is poorly absorbed. All rats given Disperse Blue 1 orally at concentrations up to 3 g/kg survived. Reduced body weights and blue tissue samples were observed in short-term, subchronic, and chronic animal studies. No skin irritation was observed with concentrations up to 10%, but Disperse Blue 1 was a moderate sensitizer in guinea pigs. Disperse Blue 1 was mutagenic in several test systems. In feeding studies, the ingredient produced a significant increase in urinary bladder neoplasms in male and female rats. Equivocal results were reported in studies with male mice and negative results were reported for female mice. A dermal carcinogenesis study in mice was negative. Further evaluation of the carcinogenesis data suggests that the urinary bladder neoplasms appear to be associated with bladder calculi rather than arising from a genotoxic mechanism. Such bladder calculi do not appear to form in humans. Based upon these data and the facts that dermal exposure produced no evidence of carcinogenesis, that the ingredient is poorly absorbed, and that exposure to hair dyes is brief, it was concluded that Disperse Blue 1 is safe for use in hair dyes at concentrations up to 1%.
A Clinicopathological Study of Urinary Bladder Neoplasms in Patients at Three Centers in Khartoum, Sudan
