Methods for the estimation of the excretion of proxicromil and its metabolites in the milk of nursing rat mothers

Abstract

The excretion of proxicromil [an antiallergy agent] and its metabolites into the milk of nursing rat mothers and its ingestion by rat pups were investigated. The methodology employed hand-milking of the mothers and analysis of suckling rat pups or their stomach contents. The most dependable of the methods used was the analysis of the stomachs of suckling rat pups. This method provided a useful index of radioactivity excreted into milk and allowed calcualtion of neonate exposure. At a maternal dose level of 20 mg/kg, a significant proportion of the dose (1-2%) was excreted into the milk. Analysis of milk taken from rat pup stomachs indicated that both proxicromil (63%) and its hydroxylated metabolites (37%) were present in the milk.