COUPLING OF HPLC WITH F-19-NMR AND H-1-NMR SPECTROSCOPY TO INVESTIGATE THE HUMAN URINARY-EXCRETION OF FLURBIPROFEN METABOLITES

Results of an on-line HPLC-NMR analysis of human urine from a volunteer administered the anti-inflammatory drug flurbiprofen are reported. The two major human urina metabolites, namely the glucuronides of flurbiprofen and of 4'-hydroxyflurbiprofen, have been identified using H-1- and F-19-NMR spectroscopy. In vivo conjugation of the racemic drug and its metabolites with D-glucuronic acid results in diastereomeric molecules which give resolved NMR spectra thereby permitting the diastereomeric proportions to be evaluated. The cause of the observed deviation from equal proportions is discussed. This study represents the first use of both F-19- and 600 MHz H-1-NMR spectroscopy coupled to HPLC.