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,
I Should Have Known Better scene of "A Hard Day's Night". It was in fact filmed in a van, with crew members rocking the vehicle to fake the action of a train in motion. Paul McCartney is seen lip-syncing in the song in both the train scene and in the live performance at the end of the film, despite not singing in the actual recording. I Should Have Known Better "I Should Have Known Better" is a song by English rock band the Beatles composed by John Lennon (credited to Lennon–McCartney), and originally issued on "A Hard Day's Night", their soundtrack for the film of