Abstract: | Stereoselective CE method for investigations of pharmacokinetics of ketoprofen enantiomers (KTP) in patients taking also other drugs is proposed, to establish relation between levels of KTP enantiomers in blood and synovial fluid of patients with rheumatoid arthritis. Resolution of the analytes was obtained in silica capillary filled with chiral selector-heptakis 2,3,6-tri-O-methyl–β-cyclodextrin in triethanolamine-phosphate buffer. Calibration curves for enantiomers in plasma and synovial fluid were linear in the range of 0.25–50.0 mg L−1, but 1.0–250.0 mg L−1 in urine. Concentrations of KTP enantiomers in synovial fluid measured at 4 h after the administration of a tablet with racemic KTP were insignificantly greater (−)-R = 1.07 ± 0.66; (+)-S-KTP = 1.13 ± 0.65 mg L−1] than in plasma (−)-R = 0.86 ± 0.37; (+)-S-KTP = 0.96 ± 0.42 mg L−1]. The validated method has been successfully applied for the determination of KTP enantiomers in biological fluids of patients with rheumatoid arthritis. |