DETERMINATION OF DRUGS IN BIOLOGICAL-FLUIDS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ONLINE SAMPLE PROCESSING

An automated two column HPLC system with the new packing material LiCh rospher RP-18 ADS (alkyl-diol-silica) was tested for the determination of several drugs and metabolites (talinolol, celiprolol, metoprolol, oxprenolol, triamterene, trimethoprim, tiracizine, artcaine, detajmium , ajmaline, lamotrigine) in various biological fluids (serum, urine, i ntestinal aspirates, supernatants of cell cultures and supernatants af ter protein denaturation). The method allows the direct injection of b iological fluids into a reversed-phase HPLC system and on-line clean-u p and sample enrichment by a column-switching technique. Precision, ac curacy and sensitivity were similar to conventional assays as describe d in the literature. With this new method it was possible to measure d rug concentrations in various biological fluids without changing the s ample preparation procedure. In some cases an additional sample prepar ation like protein denaturation or solid-phase extraction was advantag eous to enhance the sensitivity of the method and the life-time of the ADS column. (C) 1998 Elsevier Science B.V.