chemistry of aspirin, an every day drug..

Basically, when we have a headache or pain in any part of our body, it is likely that we take aspirin. This drug is probably one of the most common and best known drug in the world. Aspirin is a pain killer that reduces inflammation. It also reduces or prevent the risk of a heart attack.

The major chemical component of aspirin is known as Salicin and its derivative Salicylic Acid has similar properties. The chemical structure of salicin is based on a hexagonal "Benzene ring" with two additional side groups, one of which is a hydroxyl group (-OH) and the other a carboxylic group (-COOH). Salicin and its derivative Salicylic Acid can cause horrendous digestive problems, therefore, Salicylic Acid is reacted with another chemical to change the hydroxyl group (-OH) on the benzene ring to an Acetyl group (-OCOOH) which makes it less harmfull. The chemical formed is called Acetyl salicydic Acid (ASA).

Diagramatic representation of the structure, composition and synthesis of Aspirin.


Aspirin when taken, binds to an enzyme (cylo oxygenase-2) in cells. This enzyme is produced in large quantities by damaged calls and they are responsible for pain. In the absence of ASA, this enzymes produce Prostaglandins which send messages to the brain that a part of the body is in pain. They also cause damaged cells to rlease fluid from blood and thus, become inflamed. When ASA is taken, the enzyme is no longer able to produce prostaglandins thus, messages to the brain that a part of the body is in pain is reduced and hence, the feeling of pain and also inflamation is reduced.

ASA also hinders the production of prostaglandins in the blood stream. Prostaglandins are involved in blood clotting, this is one reason why many older people take aspirin continually, to prevent blood clots in their blood stream andby so doing, reduce the risk of heart attack.