Acetaminophen

Acetaminophen, systematically named N-(4-hydroxyphenyl)acetamide and commercially designated as paracetamol, is classified among acetanilide-derived antipyretic analgesics. First synthesized by Morse in 1878, its initial clinical application was documented by Von Mering in 1893. The compound achieved over-the-counter approval in the United States in 1955, with Chinese domestic production initiated during the late 1950s according to Chemicalbook documentation.

The compound maintains chemical stability at temperatures below 45°C. Under humid environmental conditions, however, it undergoes hydrolytic degradation to yield p-aminophenol, which subsequently undergoes oxidative transformation. This degradation pathway is visually identifiable through progressive chromatic transition from pinkish hue to brown coloration, ultimately developing black pigmentation. Therefore, optimal preservation requires maintenance in cool, desiccated storage environments.

This pharmaceutical substance manifests as white crystalline structures or powdered crystals, exhibiting a characteristic melting point between 168-172°C. It is characterized by absence of odor and a mildly bitter taste profile, demonstrating high solubility in heated aqueous and ethanolic solutions, moderate dissolution in acetone, and negligible solubility in both cold aqueous media and petroleum ether.