Biotransformation of drugs: quantitative structure-activity relationships for barbiturates, tertiary amines, and substituted imidazoles.

When using free energy-related physicochemical parameters, stimulation of NADPH oxidation by barbiturates and the N-oxidation of tertiary amines was found to be primarily dependent upon the lipophilic character of the substrates as measured by log P, where P is the partition coefficient from either 1-octanol-water or corn oil-water solvent systems. In contrast, the inhibition of epoxidation of aldrin by a series of substituted imidazoles appears to be much more dependent on electronic (sigma) and steric (Es) effects of the inhibitors.