Xanthine oxidase inhibitors: patent landscape and clinical development (2015-2020).

INTRODUCTION: Xanthine oxidase (XO) is a molybdoflavoprotein that catalyzes the oxidative hydroxylation of purines to produce uric acid and reactive oxygen species. These reaction products can cause severe disease conditions like hyperuricemia which makes XO enzyme, an important therapeutic target in diseases like gout. AREAS COVERED: Herein, patents from 2015 to 2020 are discussed to disclose the synthetic, as well as natural compounds, claimed to inhibit XO enzyme. The article also presents the last five years of clinical progression of some prominent XO inhibitors. EXPERT OPINION: There has been considerable creativity in the discovery of novel XO inhibitors in the last five years that falls outside the purine scaffold. Along with the evaluation of synthetic compounds, natural compounds can also be an area of interest for the discovery of novel XO inhibitors. Based on the patent literature of last five years, we can expect a burst of novel alternate compounds in the near future which could have the ability to reduce the uric acid level, by inhibiting XO enzyme in patients, which at the moment are striving hard to fight against the dreadful disease condition like gout.