Chronic toxicity/carcinogenicity study of FD & C Blue No. 2 in rats.

FD & C Blue No. 2 was fed to rats in the diet in a long-term toxicity/carcinogenicity study. The study included an in utero phase in which the compound was administered to groups of 60 male and 60 female Charles River CD albino rats at levels of 0.5, 1.0 and 2.0%. Two concurrent control groups, each containing 60 rats of each sex, received the basal diet. After random selection of the F1 animals, the long-term phase was initiated at the same dietary levels, with 70 rats of each sex in each dose group and in each of two control groups. Maximum exposure was 30 months. No consistent compound-related biologically adverse effects were noted. There were random statistically significant differences from the controls with respect to body weight, food consumption and clinical chemistry tests. Food consumption by the test groups showed a dose-related increase. This was probably due to the non-nutritive character of the colouring. A statistically significant increase in gliomas in the high-dose male rats was not found to be biologically significant, since none of the criteria for determining the neurocarcinogenic potential of chemical substances was met. The overall brain-tumour incidence in this study was within the range typical for 2-yr-old CD rats. Under the conditions of this study, FD & C Blue No. 2 did not produce evidence of any toxicity, including carcinogenicity.