Acetylsalicylic acid,(Aspirin) is a well-known analgesic with the chemical formula C₉H₈O₄. It is also referred to as 2-acetoxybenzoic acid. Aspirin appears as a colourless to white crystalline powder. While typically odourless, it acquires a vinegar-like smell of acetic acid in moist air. It has a flashpoint of 482°F and is widely used for treating pain, inflammation, and fever.
Acetylsalicylic acid (ASA) is a potent and irreversible platelet aggregation inhibitor. However, its effectiveness diminishes after first-pass deacetylation to salicylic acid (SA). Introduced into the pharmaceutical industry over 100 years ago, Aspirin was initially developed as an analgesic but soon found numerous medicinal applications.
The German chemist Felix Hoffmann, working at Bayer Pharmaceutical Company in 1894, sought a remedy for his father’s arthritis. Building on earlier work with salicin and salicylic acid, Hoffmann buffered salicylic acid to create acetylsalicylic acid (ASA). This new compound had improved tolerability and reduced gastrointestinal side effects. By 1899, it was marketed under the name Aspirin.
Recognised as one of the safest and most effective medicines, Aspirin is listed on the World Health Organization’s List of Essential Medicines. It is one of the most commonly used medications worldwide.
Acetylsalicylic Acid exhibits reactivity under various conditions:
(Session 2025 - 26)