Isolation of an unknown metabolite of the non-steroidal anti-inflammatory drug etodolac and its identification as 5-hydroxy etodolac

The non-steroidal anti-inflammatory drug etodolac is extensively metabolize d in the liver. Renal elimination of etodolac mainly as glucuronide and its other phase I and phase II metabolites is the primary route of excretion. High-performance liquid chromatography assays of human urine after applicat ion of etodolac indicated the existence of a further monohydroxylated metab olite (metabolite X) that was identified as 5-hydroxy etodolac. For the ide ntification, electrospray ionization mass spectrometry (ESI-MS) as well as H-1-nuclear magnetic resonance H-NMR) and C-13-NMR spectroscopy have been u sed. (C) 2001 Elsevier Science B.V. All rights reserved.