Glossary
Active Pharmaceutical Ingredient (API) / Drug Substance
Also writtenactive substance
A substance or mixture of substances used in manufacturing a medicine that becomes the active ingredient in the finished product.
Related sections
Related terms
Real inspection findings
Findings from regulators' inspection documents in which this term appears.
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Failure to prepare, review, and approve documents related to the manufacturing of API in accordance with written procedures.
FDA · FDA Warning Letter · 2024-12-17 -
You failed to conduct adequate identity testing on incoming components, including APIs, used in the manufacture of your drug products.
FDA · FDA Warning Letter · 2025-10-07 -
Several API lots were released into production without performing adequate acceptance testing…
FDA · FDA Warning Letter · 2022-08-30
Counted as of 2026-09-24 — the search you land on shows today's figures, so it may differ slightly.
Source
ICH Q7, Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, §20 Glossary, Active Pharmaceutical IngredientGRM Regulatory Glossary
243 GMP terms in one place
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