Methaemoglobin formation induced by aromatic amines and amides

Abstract

Two series of anilides have been examined for their ability to induce the formation of methaemoglobin in cats. The first series is one in which the aniline was acylated by a series of acids and the second is one in which alkyl groups were substituted on the benzene ring and the acyl moiety kept as the acetyl group. In neither series was any correlation found between the methaemoglobin-forming ability and stability of the amide group. In the first series, as the size of the acyl group was increased so the activity rose to a peak and then declined. It is suggested that this phenomenon is related to absorption of the compounds from the gastrointestinal tract. In the second series a parallelism in response was observed between amides given orally and the corresponding amines administered intravenously, suggesting that the nature of the amine liberated on hydrolysis is the major determining factor in the methaemoglobin forming ability of amides.