RAPID, SENSITIVE AND DIRECT CHIRAL HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR KETOPROFEN ENANTIOMERS

The stereospecific HPLC assays reported for ketoprofen (KT) mainly uti lize indirect approaches. These assays involve the formation of amide diastereomeric derivatives, which are then separated by chromatography . The advantages of indirect methods include versatility, good sensiti vity and cost effectiveness; however, lengthy preparation time is ofte n required. Therefore, we have developed a new direct stereospecific H PLC assay for KT enantiomers to improve preparation time and sensitivi ty. The KT enantiomers and indomethacin, internal standard (I.S.), wer e resolved using a Chiralpac AD column attached to 5 cm Supelcosil LC- SI at constant temperature (30 degrees C). The mobile phase consisted of hexane-isopropanol-trifluoroacetic acid (90:10:0.1). Under chromato graphic conditions employed R-KT, S-KT and I.S. were eluted at 12, 14 and 16 min, respectively. A linear concentration response relationship was found (0.05-5.0 mu g/ml of enantiomers) which covered normally ob served concentrations in plasma after conventional doses of KT. The mi nimum quantifiable concentration of the assay was found to be 0.025 or 0.25 mu g/ml based on 1 mi of human or 0.1 mi of rat plasma samples, respectively. This direct HPLC method is suitable for pharmacokinetic studies of KT enantiomers and offers the advantages of shorter sample preparation and run time. This method is at least as sensitive as assa ys currently in use.