According to the new Generic Drug User Fee Act (GDUFA) for the marketing authorisation of generic drugs in the USA, the Drug Master File (Type II) for APIs must undergo a completeness assessment (see our GMP News from 11 October 2012). The approach is described in the Draft Guidance for Industry entitled "Initial Completeness Assessment for Type II API DMFs under GDUFA" from October 2012.

Which information about the stability of the API contained in a generic drug is required in a Drug Master File submitted for a marketing authorisation application? The answers to this question can be found in a Q&A document published by the FDA on 26 August 2013 entitled "Guidance for Industry; ANDAs: Stability Testing of Drug Substances and Products; Questions and Answers". This Q&A document refers to the "Guidance for Industry; ANDAs: Stability Testing of Drug Substances and Products" which was released 2 months before and tackles a range of outstanding issues with regard to stability data of APIs and finished products for the marketing authorisation application of generic products.

The statements laid down in the Q&A document regarding the stability data of the API required in a DMF are explicit: in addition to the stability protocol and commitments, data demonstrating the beginning of stability studies have to be provided. The initial and one additional time point for the accelerated studies and long-term studies are sufficient. Yet, the DMF holder should provide amending data to keep the DMF as up-to-date as possible. This is the only way to ensure the successful completeness assessment by the reviewer in the Office of Generic Drugs (OGD) of the FDA. Furthermore, stability data from production scale batches are also accepted. Three production batches are necessary. The data must come from 6 months of accelerated data and long-term data covering the proposed retest period.

The Q&A document contains a range of other interesting clarifications like for example a concrete explanation of the term "small scale" with regard to the various dosage forms.

The Q&A document is a "Draft Guidance". Comments regarding the document should be submitted to the eRulemaking programme.