Research Area: Metabolic Disease Biological Activity: Febuxostat (Uloric) is a non-purine selective XAO inhibitor with IC50 of 114 -210 nM.It works by non-competitively blocking the channel leading to the active site on xanthine oxidase. [1] Xanthine oxidase is needed to successively oxidize both hypoxanthine and xanthine to uric acid. Hence, febuxostat inhibits xanthine oxidase, therefore reducing production of uric acid. [2][3]