Biotransformation and disposition of the coumaphos metabolite 3-chloro-4-methyl-(4-14C)-7-hydroxycoumarin in rats.

The biotransformation and disposition of 3-chloro-4-methyl-(4-14C)-7-hydroxycoumarin [(14C) chlorferron] were investigated in rats after single oral administration. Following administration of (14C) chlorferron at 0.5 and 20 mg/kg body weight to male rats, greater than 90% of the given dose was eliminated in the urine (77-84%) and faeces (7-15%) within 24 h. Low levels of (14C) chlorferron derived residues were detected in different organs of rats 7 days after dosing. Administration of (14C) chlorferron at 20 mg/kg allowed the isolation of three metabolites in the 24-h urine of male and female rats. Compounds tentatively identified were dechlorinated metabolites of chlorferron besides unchanged chlorferron. The majority of the metabolites were excreted in conjugated forms. The pattern of biotransformation of chlorferron was qualitatively similar in male and female rats. Comparative studies on the elimination and biodistribution of (14C) chlorferron and its parent compound (14C) coumaphos in male rats indicated rapid metabolism and faster elimination of chlorferron and its metabolites from the body than that of the parent compound.