Carcinogenesis Studies of C.I. Acid Orange 10 (CAS No. 1936-15-8) in F344 Rats and B6C3F1 Mice (Feed Studies).
Carcinogenesis studies of 80% pure C.I. Acid Orange 10 (a monoazo textile dye) were conducted by feeding to groups of 50 male and 50 female F344/N rats diets containing 1,000 or 3,000 ppm C.I. Acid Orange 10 for 103 weeks. Groups of 50 male and 50 female B6C3F1 mice were fed diets containing 3,000 or 6,000 ppm for 103 weeks. Groups of 90 male and 90 female untreated rats and 50 male and 50 female untreated mice served as controls. Mean body weights and clinical signs of control and dosed rats and mice were comparable. Because no toxic effects or consistent weight differences were observed, the rats and mice may have been able to tolerate higher doses. In male rats with neoplastic nodules of the liver, the dose response trend was positive (P<0.05) and the incidence in the 3,000 ppm group was increased (P<0.05) compared to controls (control, 5/90, 6%; low dose, 3/50, 6%; high dose, 8/50, 16%). One male rat in the high dose group had both a neoplastic nodule and a carcinoma of the liver. This marginal increase in liver cell neoplasms may have been associated with the dietary administration of C.I. Acid Orange 10. For both dose groups of male and female rats, leukemia was significantly (P<0.05) decreased in a dose related (P<0.005) trend (male: 22/90, 24%; 4/50, 8%; 3/50, 6%; female: 16/88, 18%; 2/50, 4%; 0/50). No compound-related nonneoplastic or neoplastic lesions were observed in the female rats or in mice of either sex. For 103 weeks C.I. Acid Orange 10 was given in the diets of male and female F344/N rats (0, 0.1, or 0.3%) and of male and female B6C3F1 mice (0, 0.3%, or 0.6%). Under these conditions, there was no evidence of carcinogenicity for male and female F344/N rats or for male and female B6C3F1 mice. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative Synonym: 7-hydroxy-8-(phenylazo)-1,3-naphthalenedisulfonic acid, disodium salt