EDMF / ASMF: the open part and the closed part explained

The two-part structure

An EDMF (European Drug Master File), also called ASMF (Active Substance Master File), is presented in two parts:

• Applicant's Part / Open Part — shared with the finished-product manufacturer and the authority. Contains general information: name, manufacturer, route of synthesis (overview), specifications, test methods, stability, TSE data.
• Restricted Part / Closed Part — seen only by the authority. Contains the confidential manufacturing details: full synthesis, process validation, impurity profiles, starting-material controls.

Why it is structured this way

The split lets an API manufacturer protect its process know-how while still giving regulators everything they need to assess quality. The finished-product maker never sees the confidential closed part.

How it is referenced in a filing

In the marketing-authorisation application, the applicant cites the EDMF by its reference number and version, and includes the open part. The authority reviews both parts together.

Practical checklist for buyers

• Ask for the EDMF/ASMF reference number and the latest version/date.
• Confirm the open part is available to you for your dossier.
• Check whether a Written Confirmation is needed for import into the EU (see our guide on Written Confirmation).
• Verify GMP status of the manufacturing site.

We maintain EDMF/ASMF dossiers for several key APIs and provide the open part to qualified partners under NDA.

General information only; not legal or regulatory advice. Requirements change — always confirm with the competent authority.