pharmacopoeia

A pharmacopoeia is an official reference book that sets the legally recognized standards for medicines: what each drug and excipient must be, how pure it must be, and how to test it. Think of it as the rulebook that defines what may legitimately be called, say, aspirin in a given country.

Its core content is the monograph — a standardized entry for each substance or product giving its definition, identification tests, purity limits, assay method and acceptance criteria. Pharmacopoeias also describe general methods, such as how to run a dissolution test or measure tablet friability, so that laboratories everywhere test the same way.

Major pharmacopoeias include the United States Pharmacopeia, the European Pharmacopoeia and the British Pharmacopoeia, alongside national ones such as the Chinese Pharmacopoeia. Where a country recognizes a pharmacopoeia, its standards are not mere advice but enforceable requirements, and a product failing its monograph is legally substandard.