The major aim of this work is to demonstrate the applicability of micellar electrokinetic capillary chromatography with SDS based pseudostationary phase for the screening of cytochrome P450 inhibitors. In contrast with the other capillary electrophoresis modes the cytochrome P450 reaction mixture thus could be used for the analysis without any pre-treatment. Cytochrome P450 2C9, one of the most important isoforms in human liver, was chosen as a model example for this study in combination with diclofenac as a probe substrate. The inhibitory effect on the given cytochrome P450 reaction was evaluated for two inhibitors with different inhibition potential - strong inhibitor sulfaphenazole and moderate inhibitor ketoconazole. As a result 50% inhibitory concentrations IC(50) and inhibition constants K(i) were evaluated; their values for both inhibitors were in a good agreement with the literature data determined by different methods.

Department of Biochemistry Faculty of Science Masaryk University Kamenice 5 62500 Brno Czech Republic