Glucuronic acid (α-D-GLUCURONIC ACID) is a carboxylic acid that has the structure of a glucose molecule that has had its sixth carbon atom (of six total) oxidized. The salts of glucuronic acid are known as glucuronates. Glucuronic acid is highly soluble in water. In humans, glucuronic acid is often linked to toxic or poisonous substances to allow for subsequent elimination, and to hormones to allow for easier transport. These linkages involve O-glycosidic bonds. The process is known as glucuronidation, and the resulting substances are known as glucuronides (or glucuronosides). Glucuronidation uses UDP-glucuronic acid (glucuronic acid linked via a glycosidic bond to uridine diphosphate) as an intermediate. UDP-glucuronic acid is formed in the liver of all animals. α-D-GLUCURONIC ACID is used as pharmaceutical intermediate and in chemical research.