STEREOSPECIFIC HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY OF KETOPROFEN IN HUMAN PLASMA AND URINE

A high-performance liquid chromatographic (HPLC) assay suitable for the analysis of the enantiomers of ketoprofen (KT), a 2-arylpropionic acid (2-APA) non-steroidal antiinflammatory drug (NSAID), in plasma and urine was developed. Following the addition of racemic fenoprofen as internal standard (I.S.), plasma containing the KT enantiomers and I.S. was extracted by liquid-liquid extraction at an acidic pH. After evaporation of the organic layer, the drug and I.S. were reconstituted in mobile phase and injected into the HPLC system. The enantiomers were separated at ambient temperature on a commercially available 250 x 4.6 mm amylose carbamate-packed chiral column (Chiralpak AD) column with hexane-isopropyl alcohol-trifluoroacetic acid (80:19.9:0.1, v/v/v) as the mobile phase pumped at 1.0 ml/min. The enantiomers of KT were quantified by ultraviolet detection with the wavelength set at 254 nm. The assay described allows for the direct quantitation of KT enantiomers without pre-column derivatization, and is suitable for clinical studies of KT enantiomers in human plasma and urine after administration of therapeutic doses.