HIGHLY SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC TANDEM MASS-SPECTROMETRIC METHOD FOR THE ANALYSIS OF DEXTROMETHORPHAN IN HUMAN PLASMA

A stable-isotope-dilution HPLC-tandem mass spectrometry-based method w as developed for the determination of dextromethorphan in human plasma . Plasma samples were prepared for analysis by solid-phase extraction on octadecylsilane extraction cartridges. Dextromethorphan and the deu terium-labeled dextromethorphan internal standard were chromatographed on a short reversed-phase column and detected by a selected-reaction- monitoring scheme. Linear standard curves were obtained over three ord ers of magnitude and the limit of quantitation for dextromethorphan wa s 50 pg/ml, using a 1-ml plasma sample. The combination of HPLC and el ectrospray tandem mass spectrometry resulted in a rapid, selective and sensitive method for the analysis of dextromethorphan in plasma. The method was applied for the evaluation of the pharmacokinetic profile o f dextromethorphan in human volunteers following peroral administratio n. (C) 1997 Elsevier Science B.V.