Blog / Regulatory
What a Drug Master File is, and how a Letter of Access works
A plain guide for formulators: what an API maker files in a DMF, what stays confidential, and what a Letter of Access lets you reference.
If you buy an active pharmaceutical ingredient for a regulated market, two documents shape the relationship with your supplier long before the first drum ships: the Drug Master File and the Letter of Access.
What a Drug Master File is
A Drug Master File (DMF) is a confidential submission an API manufacturer makes to a regulator. It describes how the substance is made, controlled and tested: the route of synthesis, starting materials, impurity profile, specifications, analytical methods and stability data. In the United States it is filed with the FDA as a Type II DMF. Europe uses the Active Substance Master File, often still called an EDMF, and Korea has its own KDMF system.
A DMF is not approved or rejected by itself. It is reviewed only when a finished-dose applicant references it in their own application.
Why part of it stays closed
The file lets a manufacturer protect process know-how while still giving the regulator everything it needs. In the European format this is explicit: an applicant's part, shared with the customer, and a restricted part seen only by the authority.
What a Letter of Access does
A Letter of Access (LoA), also called a letter of authorization, is the manufacturer's written permission for the regulator to consult the DMF on behalf of a named applicant and product. It does not hand you the file. It tells the agency: when this company's dossier arrives, you may read ours in support of it.
What to have ready when you ask for one
- The API and the file you want to reference (USDMF, EDMF or KDMF)
- The applicant's legal name and address
- The dossier type and the market it is going to
- The finished product and strength, where the agency requires it
Questions worth asking your supplier
- Is the file current, and when was it last updated?
- How are process changes notified to holders of a Letter of Access?
- Which specification and pharmacopoeial grade does the file support?
Nivika holds USDMF 26343 for Nebivolol hydrochloride. If you need to reference it, use the enquiry form and choose Letter of Access.