THE TOXICITY AND METABOLISM OF MESIDINE AND PSEUDOCUMIDINE IN RATS

¹ Division of Pharmacology and Toxicology, Food and Drug Administration, U.S. Department of Health, Education and Welfare, Washington, D.C.

The toxicities of the aromatic amines mesidine, pseudocumidine and other amines derivable from the dye Ponceau 3R were studied individually in rats, and the metabolic fates of the amines were determined after p.o. intake. The toxicity studies included an oral toxicity test and a 6-month subacute feeding study. A general pattern was observed in which the number of methyl groups on the aromatic ring and the arrangement of such groups influence toxicity. Metabolic studies with mesidine and pseudocumidine, when correlated with known metabolic pathways of other amines in Ponceau 3R, were found to be useful in understanding the differences in toxicity among these compounds. The greater toxicity of mesidine and pseudocumidine as compared with many other amines derivable from Ponceau 3R can be explained, in part, by their greater resistance to oxidative metabolism and to the greater toxicity of their metabolites.