Xanthine oxidase-IN-4 (compound 19a) is an orally active and potent xanthine oxidase (XO) inhibitor, with an IC 50 of 0.039 μM. Xanthine oxidase-IN-4 exhibits hypouricemic potency in potassium oxonate induced hyperuricemia rats. Xanthine oxidase-IN-4 can be used for hyperuricemia and gout research.