Anand M. Lahoti

Febuxostat is a novel, non-purine, selective inhibitor of xanthine oxidase for hyperuricemia in patients with gout. It is the first promising substitute for allopurinol in 40 years. Various synthetic routes to febuxostat, as well as polymorphic forms and impurities of the drug, are reported in the literature. The authors have also identified several impurities that result from the synthesis of febuxostat. This article describes the identification and control of all isomeric, carryover, and byproduct impurities of febuxostat and its intermediates.