Reversed phase high-performance liquid chromatography of heterocyclic aromatic N-oxides: application to measurement of N-oxidation by microsomes and rat hepatocytes in primary culture.

1. The rates of N-oxide formation from pyridine, nicotinamide and isonicotinamide by rat liver microsomes and by cultured rat hepatocytes have been quantified using a simple h.p.l.c. system. 2. Hepatocytes produce hetero-aromatic N-oxides for at least 5 h, making them a useful system to study the N-oxidation of pyridines.