Liquid chromatography-mass spectrometry in metabolic research. I. Metabolites of benzbromarone in human plasma and urine.

Seven benzbromarone metabolites were identified in human plasma and urine by electron-impact mass spectrometry after semipreparative high-performance liquid chromatographic fractionation and/or by liquid chromatography-mass spectrometry using a thermospray interface. The major metabolite in plasma and urine was a hydroxybenzofuranoyl species; the 1-hydroxyethyl entity was identified as a minor metabolite. Five urinary metabolites occurred in trace amounts, all of them carrying OH and/or C = O groups in different positions. The hydroxybenzofuranoyl metabolite has often been mistaken for benzarone in previous studies.