High-performance liquid chromatographic analysis of the enantiomers of flurbiprofen and its metabolites in plasma and urine.

Reversed-phase high-performance liquid chromatographic methods have been developed to quantitate the R- and S-enantiomers of flurbiprofen and its major metabolites, 4'-hydroxyflurbiprofen, 3'-hydroxy-4'-methoxyflurbiprofen, and 3',4'-dihydroxyflurbiprofen. The compounds are extracted from plasma or urine and derivatized with S-(alpha)-methylbenzylamine to form diastereomeric amides which are readily separated on a C18 column. Fluorescence detection resulted in detection limits that readily allowed us to characterize the disposition of R- and S-flurbiprofen and its major metabolites in man following therapeutic doses.