DETERMINATION OF A SUBSTANCE-P ANTAGONIST IN HUMAN PLASMA AND URINE USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ULTRAVIOLET ABSORBENCY AND TANDEM MASS-SPECTROMETRIC DETECTION

A high-performance liquid chromatographic (HPLC) assay using ultraviol et (UV) detection was developed and compared with a HPLC method with t andem mass spectrometric (HPLC/MS-MS) detection for the determination of a substance P receptor antagonist nyl-4-((3-oxo-1,2,4-triazol-5-yl) methyl)morpholine (Fig. 1, Ia, L-742 694) in human plasma and urine. T he drug was isolated from the biological matrix through liquid-liquid extraction. In the HPLC/UV method, the samples were initially injected onto a cyano Hypersil column, and the chromatographic region containi ng the peaks of interest was heart-cut onto an analytical C-18 Hypersi l column via a column switching device. The analyte was quantified by monitoring absorbance at 205 nm. The limit of quantification for I ext racted from 1 ml of plasma or urine was 2.5 ng ml(-1), and the assays were validated in the concentration range 2.5-500 ng ml(-1). The HPLC/ MS-MS method was validated in the concentration range 0.2-500 ng ml(-1 ). Both assays provided data with precision, measured as coefficient o f variation, better than 10% at all points within the standard curve r ange and with adequate accuracy. (C) 1997 Published by Elsevier Scienc e B.V.