Identification of four new metabolic products of metoclopramide using mass spectrometry.

1. N-(Diethylaminoethyl)-4-amino-5-chloro-2-methoxybenzamide (metoclopramide, I) N-(ethylaminoethyl)-4-amino-5-chloro-2-methoxybenzamide (II), N-(aminoethyl)-4-amino-5-chloro-2-methoxybenzamide (III), N-(2'-hydroxyethyl)-4-amino-5-chloro-2-methoxybenzamide (IV), N-(diethylaminoethyl)-4-amino-5-chloro-2-hydroxybenzamide (V) and N-(ethylaminoethyl)-4-amino-5-chloro-2-hydroxybenzamide (VI) were obtained from chloroform extracts of incubation mixtures of I or II (HCl salts) with 9000 g liver microsomal preparations from male rabbits.