Discovery of a potent and selective COX-2 inhibitor in the alkoxy lactone series with optimized metabolic profile

Novel approach to pro-drugs of lactones: water soluble imidate and ortho-ester derivatives of a furanone-based COX-2 selective inhibitor

Interest in water soluble COX-2 inhibitors that can be administered intravenously led to the development of novel pro-drugs of a furanone based COX-2 inhibitor 2. Transforming the lactone moiety of the furanone to an imidate or an ortho-ester with a hydrophilic, endogenous appendage resulted in water soluble pro-drugs that converted to the parent drug in vivo.

Discovery, Biosynthesis, and Structure Elucidation of Metabolites of a Doping Agent and a Direct Analogue, Tetrahydrogestrinone and Gestrinone, Using Human Hepatocytes

Tetrahydrogestrinone (18a-homo-pregna-4,9,11-trien-17beta-ol-3-one, THG) is an anabolic androgenic steroid sold to athletes as an undetectable performance enhancer. Being an unapproved substance, no legitimate in vivo human excretion studies could be performed to identify urinary markers of this doping agent. In vitro systems were used as an alternative approach to study the human metabolism of THG and the gestrinone analogue, which is a marketed drug. Incubations of both compounds in the presence of human hepatocytes led to formation of oxidative and glucuroconjugated metabolites. Microgram quantities of the major in vitro metabolites were biosynthesized using human hepatocytes, characterized by HPLC/MS/MS, and their structures elucidated by NMR. Due to high structure similarity, both THG and gestrinone had an analogous in vitro metabolic pathway leading to successive addition of a hydroxyl and a beta-glucuronic acid at C-18. This in vitro metabolite of gestrinone was consistent with a previously reported major but unknown human urinary metabolite. The structure of another metabolite of THG was proposed to be a glucuroconjugate of an oxidative product with a hydroxyl group most likely at C-16epsilon. In vitro information reported therein could significantly impact the identification of new urinary markers of THG for doping control purposes.