Formation of catechol-like and monophenolic metabolites of propranolol by the rat liver 9000G supernatant.

The oxidation of the naphthalene ring system of propranolol by the rat liver 9000g supernatant has been studied by gas chromatography-mass spectrometry. Two dihydroxy metabolites, one of which possibly catechol-like, and four monophenols were identified based on the mass fragmentation pattern and retention times of their trimethylsilyl and d9-trimethylsilyl derivatives. These observations emphasize the complex oxidation pattern of this drug. All metabolites identified are proposed to be associated with significant biological activity.