Teratological evaluation of FD&C red no.2-a collaborative government-industry study. I Introduction, experimental materials, and procedures.

Because of recent studies indicating possible embryolethality and teratogenicity of FD&C Red. No 2, and ad hoc committee was convened by the Food and Drug Administration to consider these questions. The committee suggested a collaborative study by three laboratories [Food and Drug Administration (FDA), Industrial Bio-Test Laboratories (IBT), and National Center for Toxicological Research (NCTR)] in which Red No. 2 was given at 200 mg/kg body weight, by gavage during days 0-19, 6-15, or 7-9 of gestation. FD*C Red No. 2 was also given at the same dose level via water bottle. Appropriate controls were utilized. FDA used Osborne-Mendel strain rats, IBT used Charles River strain also showed an increase in the same parameter for the same dose level and in addition showed a significant increase in the percentage of resorptions per litter. It was concluded that because of the inherent variation and the absence of an increase in abnormalities or other indications of embryotoxicity, there is reason to doubt that this effect is either biologically significant or reproducible.