METABOLISM OF 1,4-DIHYDRO-6-TRIFLUOROMETHYLQUINOXALINE-2,3-DIONE(LILLY 72525) IN RATS AND CATS

The metabolism of 1,4-dihydro-6-trifluoromethylquinoxaline-2,3-dione (Lilly 72525), a sedative hypnotic drug, was studied in rats and cats. Plasma concentrations of Lilly 72525 were measured fluorometrically after oral and i.v. doses of the compound in rats. A comparison of the area under the 2 curves suggested that 84% of the oral dose was absorbed. Studies with 14C-labeled material in both species confirmed that the drug was well absorbed after oral adminstration and revealed that the dione was mainly eliminated unchanged in the urine. Bile duct cannulation experiments suggested that biliary excretion accounted for most or all of the drug present in feces of rats. Metabolites isolated from urinary extracts by TLC were identified by GLC-mass spectrometry. The only metabolite detected in rat urine or bile extracts was a ring-hydroxylated compound. This metabolite plus 2 N-hydroxylated metabolites were identified in extracts of cat urine.