Prodrug not its intended target. This reduces adverse or unintended effects of a drug, especially important in treatments like chemotherapy, which can have severe unintended and undesirable side effects. Many herbal extracts historically used in medicine contain glycosides (sugar derivatives) of the active agent, which are hydrolyzed in the intestines to release the active and more bioavailable aglycone. For example, salicin is a β-D-glucopyranoside that is cleaved by esterases to release salicylic acid. Aspirin, acetylsalicylic acid, first made by Felix Hoffmann at Bayer in 1897, is a synthetic prodrug of salicylic acid. However, in other cases, such as codeine and morphine,
Alendronic acid strong negative charge on the two phosphonate moieties limits oral bioavailability, and, in turn, the exposure to tissues other than bone is very low. After absorption in the bone, alendronate has an estimated terminal elimination half-life of 10 years. Alendronic acid Alendronic acid (INN) or alendronate sodium, sold in the U.S. under the trade name Fosamax among others, is a bisphosphonate drug used for osteoporosis, osteogenesis imperfecta, and several other bone diseases. It is marketed alone as well as in combination with vitamin D. Merck's U.S. patent on alendronate expired in 2008 and the drug is now available as a