HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF NEMONAPRIDE AND DESMETHYLNEMONAPRIDE IN HUMAN PLASMA USING AN ELECTROCHEMICAL DETECTION

A high-performance liquid chromatographic method using an electrochemi cal detector (HPLC-ED) was developed for the determination of nemonapr ide and its active metabolite, desmethylnemonapride in human plasma. N emonapride, desmethylnemonapride and moperone chloride, which was used as the internal standard (I.S.) in plasma, were extracted by a rapid and simple procedure based on C-18 bonded-phase extraction, and were s eparated by C-8 reversed-phase HPLC column. Nemonapride and desmethyln emonapride were detected by high conversion efficiency amperometric de tection at +0.84 V. Determination of both nemonapride and desmethylnem onapride were possible in the concentration range at 0.25-5.0 ng/ml, a nd the limit of detection for each was 0.1 ng/ml. The recoveries of ne monapride and desmethylnemonapride added to plasma were 97.0-98.2% and 96.7-98.8%, respectively, with coefficients of variation of less than 7.2% and 10.3%, respectively. This method is applicable to drug level monitoring in the plasma of schizophrenia patients treated with nemon apride and to the study of pharmacokinetics. (C) 1998 Elsevier Science B.V. All rights reserved.