Glucuronides are formed when a glucuronic acid is bound in vivo to a drug or xenobiotic. In nature, glucuronidation is one of the main phase 2 metabolic pathways by which an organism transforms a small molecule drug or xenobiotic into a more water soluble substance which may be responsible for a drug’s therapeutic affect but certainly enable its detoxification and further excretion. Glucuronides are formed enzymatically by the UDP-Glucuronosyltransferases which have been reported active in the liver, kidneys, epithelial cells of the lower gastrointestinal tract and the brain.

Enzyme-mediated Glucuronidation

Compounds featuring aliphatic alcohol and phenols are metabolized into O– glucuronide ethers whilst primary and secondary amines are metabolized into N- glucuronides. Drugs containing carboxylic acid functions are transformed into acyl glucuronides.