Second onto market this year is Febuxostat, approved on the 13th of February. Febuxostat is a xanthine oxidase inhibitor used for the treatment of hyperuricemia (gout), and competes against well established agents such as Allopurinol (Allopurinol was approved in 1964 for the treatment of gout). Febuxostat is a small molecule drug (Molecular Weight of 316.4 g.mol-1) is fully Rule-Of-Five compliant, is essentially insoluble in water, and has good oral absorption (>49% bioavailable). Febuxostat plasma half-life of 5 to 8 hours, a volume of distribution of 50L, high plasma protein binding at 99.2% (unsurprising given the lipophilic acid nature of the molecule). Febuxostat is extensively metabolised, both by the UGT system, producing glucoronidated metabolites, and also by a range of complex CYP mediated transformations (metabolites of metabolites....). Some of the CYP mediated metabolites involve hydroxylation of the butyl sidechain, these themselves are pharmacologically active again...