The measurement of theophylline metabolism in hepatic microsomes using high-performance liquid chromatography.

A method is described to measure the in vitro metabolism of theophylline by liver microsomes. The formation of 1-methyluric acid and 1,3-dimethyluric acid in incubation mixtures was determined by high-performance liquid chromatography. The formation of both metabolites was linear with time and the formation of 1-methyluric acid was blocked by allopurinol. This method will be useful in assessing potential drug interactions involving theophylline.