What Is an Active Pharmaceutical Ingredient (API)?

In short: An active pharmaceutical ingredient (API), also called a drug substance in ICH Q7, is the substance or mixture used to make a medicine that provides its intended pharmacological effect. The API is distinct from an upstream intermediate and from the finished dosage form. Regulatory classification and the boundary of API manufacture depend on the applicable region and product filing.

What is an active pharmaceutical ingredient?

An API is the substance, or mixture of substances, used in manufacturing a medicine that becomes the active ingredient in the finished drug product and is intended to provide its pharmacological activity or another direct therapeutic effect. ICH Q7 uses “API” and “drug substance” for this manufacturing concept. In U.S. CGMP, an active ingredient is defined by the effect the component is intended to provide in the drug product. See ICH Q7A (2000/2001), §§1.2 and 20, and 21 CFR 210.3(b)(7) (current eCFR edition, 2026).

The API is not the whole finished medicine. A finished product is a dosage form, such as a tablet, capsule, or solution, in its final immediate packaging. It may contain one or more active ingredients together with inactive ingredients and other formulation components.

API, starting material, intermediate, and finished product

Term	Practical meaning
API or drug substance	The material manufactured to provide the intended active effect in the finished medicine.
API starting material	A defined material introduced at the justified start of API manufacture. ICH Q7 describes it as contributing a significant structural fragment to the API; the selection and rationale depend on the process.
Intermediate	Material formed during API processing that undergoes further molecular change or purification before it becomes the API. It may be isolated or carried forward without isolation.
Finished drug product	The final dosage form intended for use or marketing, such as a tablet, capsule, injection, or solution.

These terms describe different points in a manufacturing process. A material does not become an API simply because it is sold commercially, handled in bulk, or contains an active substance. In ICH Q7, a mixture can fall within the API definition when it is intended for drug-product manufacture and becomes the active ingredient; ICH Q7 also notes that legal classification of materials can vary between regions and countries.

What is a bulk process intermediate?

“Bulk process intermediate” (BPI) is not a universal synonym for the active ingredient in a biological medicine. A process intermediate is a material made at a defined stage and may need further processing before the drug substance is complete. Use the terminology in the product’s approved filing and controlled process documents. ICH Q11 (2012) recognises that biological manufacturing can use complex upstream processes, including splitting and pooling of intermediates, and that the manufacturer should explain how drug-substance batches are defined.

Which GMP guidance applies to API manufacture?

ICH Q7 provides GMP guidance for APIs used in human medicines. Its scope covers manufacture by chemical synthesis, extraction, cell culture or fermentation, recovery from natural sources, and combinations of these routes. For APIs made through cell culture or fermentation, it includes specific guidance in Section 18. Its scope excludes vaccines, whole cells, whole blood and plasma, blood and plasma derivatives, and gene-therapy APIs; those products remain subject to applicable regional requirements.

Under ICH Q7 §1.3, the guide’s API GMP scope begins at the defined API starting material. The manufacturer should document the rationale for that boundary; for fermentation, extraction, or purification routes, the point is determined case by case. This scope statement does not remove other applicable legal, filing, or quality controls for upstream operations. ICH Q11 (2012), §§5.1–5.2, provides principles for selecting and justifying starting and source materials in the drug-substance process.

ICH guidance is harmonised guidance, not automatically a statute in every jurisdiction. ICH Q7 §1.2 notes that regions or countries may classify a material differently. Manufacturers should determine which local GMP requirements and filing commitments apply to the product and site.

Preparing for an API manufacturer audit

Example in-house criterion (not a pharmacopoeial requirement): An audit plan may use ICH Q7’s main topics as a practical checklist: quality management, personnel, premises and equipment, documentation, materials, production, packaging and labelling, laboratory controls, validation, change control, and outsourced operations. Tailor the audit to the material, process, supplier or site, and applicable regulatory commitments. This list is a planning aid; it is not a universal regulatory audit scheme.

Frequently asked questions

Is every material handled in an API plant an API?

No. Raw materials, reagents, starting materials, intermediates, APIs, and packaging materials are different categories. An intermediate still requires further processing before it becomes the API under the ICH Q7 definition.

Does ICH Q7 cover every step before the API starting material?

ICH Q7’s API GMP scope does not cover steps before the defined starting material, but the manufacturer must justify and document the boundary. Other local requirements and marketing-authorisation commitments may still apply upstream. ICH Q11 helps with selection and justification of starting materials.

Does ICH Q7 apply to every biological medicine?

No. Q7 covers some API routes that use cell culture or fermentation, but explicitly excludes certain products, including vaccines, whole cells, plasma derivatives, and gene-therapy APIs. Check the product type and applicable regional guidance.

Is an API the same as a finished drug product?

No. The API is the drug substance that provides the active effect. The finished product is the final dosage form and may include inactive formulation ingredients, packaging, and other components.

Specifications, test procedures and acceptance criteria for drug substances and products
Complaints and recalls in an API manufacturing unit
Handling laboratory reagents

Records and retention

Document the justified API starting-material boundary and maintain the controlled process and quality records required for the applicable product. Retain batch-specific GMP records at least one year after expiry of the respective product batch. EU GMP Part I Chapter 4 §4.11 requires batch documentation to be kept for one year after expiry or at least five years after Qualified Person certification, whichever is longer; 21 CFR 211.180(a), current eCFR edition (2026), requires at least one year after expiry for production, control, or distribution records specifically associated with a drug-product batch. Apply any longer applicable legal or marketing-authorisation period.

References

International Council for Harmonisation. Q7: Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, Step 4 version (10 November 2000); issued by FDA as Q7A Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients (August 2001), §§1.1–1.3, 18 and 20. FDA official guidance.
International Council for Harmonisation. Q11: Development and Manufacture of Drug Substances (Chemical Entities and Biotechnological/Biological Entities), Step 4 version (1 May 2012), §§4–5. Official ICH PDF.
21 CFR §210.3(b)(7), definition of active ingredient, current eCFR edition (2026; accessed 19 October 2026). Official eCFR.
European Commission. EudraLex Volume 4, EU Guidelines for Good Manufacturing Practice, Part I, Chapter 4: Documentation (January 2011), §4.11. Official PDF.
21 CFR §211.180(a), current eCFR edition (2026; accessed 19 October 2026). Official eCFR.

What Is an Active Pharmaceutical Ingredient (API)?