IPEC: New Stability Guide for Excipients Published

In early July, the IPEC (International Pharmaceutical Excipients Council Europe (IPEC Europe)) published the updated Version 3 of its "Excipient Stability Guide for Pharmaceutical Excipients" on its website. First published in 2010, this guide provides guidance on developing stability programs to support regulatory submissions, ensure the quality of excipients, and substantiate information on storage conditions, shelf life, and expiration dates.

This guide is a voluntary industry standard. Stability studies for excipients are generally not required for official CTD submission documents. However, depending on the specific substance, its function, and the specific application, stability data on excipients may be relevant in the context of pharmaceutical development, quality assessment, or a risk-based justification.

Version 3 of this guide has been expanded to include the following sections:

• Stability studies: Data from three risk-based stability study designs were presented and compared
• Expansion of recommendations and practical implementations on the following topics:
  - Bracketing and matrixing for similar compounds
  - Transport stability studies, bulk shelf life, ongoing stability studies, stress tests/studies, expiration dates and retest intervals, specifications and their test parameters, special stability studies (e.g., for new substances or substances used in biologics and vaccines
  - Harmonization of terminology and reduction of redundancies
• A clear distinction between the requirements for excipients and active pharmaceutical ingredients (APIs) has been established and presented.

The table of contents for the updated Version 3 of the Guide includes the following main chapters, with Chapters 1, 2, and 3 containing further subchapters and subsections:

FOREWORD
ACKNOWLEDGEMENTS
1 INTRODUCTION
2 EXCIPIENT STABILITY PROGRAMS
3 EXCIPIENT STABILITY OPTIONS
4 SHIPPING STUDIES
5 REFERENCES

Version 3 of the "Excipient Stability Guide for Pharmaceutical Excipients (Version 3, 2026)"  is available on the IPEC website and can be downloaded after registration.