Gas chromatographic mass spectrometric analysis of hydroxylamine for monitoring the metabolic hydrolysis of metalloprotease inhibitors in rat and human liver microsomes

A gas chromatographic-mass spectrometric (GC-MS) method was developed for t he analysis of hydroxylamine (HA) in supernatants obtained from liver micro somes. HA monitoring was used to determine the metabolic hydrolysis of two hydroxamic acid-based matrix metalloprotease inhibitors in rat and human li ver microsomes. The hydrolysis of the hydroxamic acids to their correspondi ng carboxylic acids releases HA as a common metabolic product. HA was deriv atized to acetone oxime by addition of acetone to the liver microsomal supe rnatant, followed by direct injection of the supernatant into the GC-MS, wi th detection of the oxime by selected-ion-monitoring. The method is simple, reproducible, and sensitive for the determination of the hydrolysis of hyd roxamic acid compounds, where hydrolysis is the major metabolic pathway. Th e methodology can be used for rank ordering and selecting hydroxamic acid a nalogs based on their susceptibility to hydrolysis. (C) 1999 Elsevier Scien ce B.V. All rights reserved.