Substituted cyclic imides as potential anti-gout agents.

N-substituted cyclic imides of phthalimide, 2,3-dihydrohalazine-1,4-dione, and diphenimide were shown to reduce the serum uric acid levels in normal and hyperuric mice at 20 mg/kg/day I.P. for 14 days. The agents were potent inhibitors of commercial xanthine dehydrogenase and xanthine oxidase enzyme activities with IC50 values from 10(-7) to 10(-8) M concentrations of drug.