Metabolism and excretion of promazine by the horse

Abstract

Abstract The urinary excretion of promazine and its metabolites has been examined in five horses, by ultraviolet spectrometry and thin-layer chromatography. In each horse, excretion continued for at least 96 h although the amount excreted was low, being about 11% of the dose. No correlation of excretion and pH or urinary volume was observed. Glucuronic acid conjugates predominated, their ratio to unconjugated metabolites being about 5:1. Promazine was found only in small amounts and traces of unconjugated sulphide metabolites were found in only one horse. At least nine metabolites of promazine were detected, the major one being the glucuronide of 3-hydroxypromazine.