Introduction: Xanthine oxidase inhibitors are currently under scrutiny as attractive therapeutics for disorders such as hyperuricemia, gout, ulcers, cancer, ischemia, hypertension and oxidative damage. The fewer side effects of non-purine xanthine oxidase inhibitors, as compared to purine analogs, make them suitable for further research, which is evidenced by the fact that many articles and patents are now being published on them in the research domain.
Areas covered: This review describes the patent literature covering both purine and non-purine analogs as xanthine oxidase inhibitors, up to December 2010, together with their recent highlights in pharmacology. Readers will gain an in-depth knowledge of patents covered and compounds discussed with their therapeutic use.
Expert opinion: Several of the compounds which are discussed in this article have IC(50) values which offer some advantages over existing molecules such as allopurinol. The available reports on X-ray crystal structures of xanthine oxidase will certainly be beneficial for the design and synthesis of novel xanthine oxidase inhibitors of diverse chemotypes.