Metabolite profiling study of propranolol in rat using LC/MS/MS analysis

Abstract

Metabolite profiling is one of the most challenging fields in applied mass spectrometry. Mass spectrometry was used to characterize the metabolites of propranolol, a β-adrenergic receptor antagonist containing numerous oxidation sites. Propranolol is extensively metabolized, with most metabolites appearing in urine. Urine samples were collected from young adult male Sprague–Dawley rats. Structural identification of various metabolites was performed by LC/MS/MS, using a PE SCIEX triple quadrupole instrument (PE SCIEX API 3000). Metabolites were itemized using several LC/MS/MS techniques, including Q3 full scan and precursor and constant neutral loss experiments. A looped experiment technique revealed the presence of mono- and di-hydroxylated metabolites as well as regio isomers of hydroxy- and dihydroxy-propranolol glucuronides and propranolol glucuronic acid. Propranolol glucuronide was not observed, while the presence of dealkylated metabolites was suggested but not confirmed. Copyright © 1999 John Wiley & Sons, Ltd. Abbreviations used: ESI, electrospray; LC, liquid chromatography; MS, mass spectrometry.