LC/MS and MS/MS in Drug Metabolism Investigations: Application for Structural Elucidation of Drug Metabolites

Abstract

Combined liquid chromatography/tandem mass spectrometry (LC/MS/MS) were used for the identification of the phase I and phase II (conjugated) metabolites of anxiolytic and antihypertensive drugs in biological matrix. These studies demonstrated that the collisionally activated dissociation (CAD) scan technique, i.e., product ion scan, precursor ion scan, and neutral loss scan, were very useful for detecting the unknown metabolites and for obtaining detailed structural information on the metabolites. Furthermore, the positional isomers of conjugated metabolites could be characterized by product ion scan analysis coupled with simple chemical derivatization.