High-throughput approaches to the quantitative analysis of ketoconazole, apotent inhibitor of cytochrome P450 3A4, in human plasma

Ketoconazole, an imidazole-piperazine compound, is an orally active antimyc otic agent, in addition, Ketoconazole is a specific inhibitor of cytochrome P450 3A4. As about 60% of oxidized drugs are biotransformed by this isofor m, the potential effect of a concomitant administration of ketoconazole on drug disposition may be of interest during drug development. The present pa per describes three different approaches (methods A, B, and C) to attain hi gh-throughput sample preparation and analysis in the quantification of keto conazole in human plasma. Method A consisted of acetonitrile precipitation in a 96-well plate, transfer of the supernatant via a Tomtec Quadra 96 Mode l 320, and subsequent injection onto a 50 x 4.6 mm (i.d.) Develosil Combi-R P-5 column (packed with C30 bonded silica particles), Method B consisted of an identical sample preparation to method A.,vith the exception that a Mic hrom Magic Bullet(TM) column, 2.0 --> 0.50 mm (i.d., tapered bore) x25 mm l ength, was used, Lastly, in method C, a turbulent-flow chromatography (Turb oFlow LC/APCI-MS/MS) module was used for the direct analysis of ketoconazol e in human plasma. A Sciex API 3000 was used in methods A and B, while a Mi cromass Quattro LC was employed in method C, Based on the values obtained f or the calibrator (standard) and quality control samples, all three protoco ls yielded satisfactory accuracy, precision, and reduced manual sample prep aration time. Copyright (C) 2000 John Whey & Sons, Ltd.