Metabolism of [14C]2-aminobiphenyl in vivo by different species.

[14C] 2-Aminobiphenyl is predominantly metabolised in vivo to 3- and 5-hydroxy conjugated derivatives in all species. In some species, 2-aminobiphenyl is also excreted to a small extent as N-conjugated derivatives. Renal excretion accounts for about 30-40% of the administered dose during the first 24 hours. The 5-O-sulphate and 5-O-glucuronide of 2-amino-5-hydroxybiphenyl have been found as major metabolites with all species; 2-amino-3-hydroxybiphenyl-O-sulphate is also a significant metabolite. There were metabolic differences observed between species in this study. HPLC and TLC analytical techniques were used for separation and detection of [14C] 2-aminobiphenyl and its metabolites. Formation of different isomeric metabolites may be explained by electronic Hückel molecular orbital calculations and stereochemical factors.