In March 2026, the now final “Guideline on the chemistry of active substances” was published on the EMA website.
As reported in the news “EMA/CHMP: New Guideline Draft on Active Substances published for Comment”, the draft guideline was open for public consultation until the end of January 2025 and has now been adopted by the Quality Working Party (QWP) and approved by the Committee for Medicinal Products for Human Use (CHMP). The guideline is due to come into force on 1 September 2026.
The purpose of this guideline is to set out the type of information required for the manufacture and control of active substances (existing or new chemical entities) used in a medicinal product. The differences in requirements for new or existing active substances are clarified in the relevant paragraphs of the guideline where applicable.
For the purposes of this guideline, an existing active substance is one that has been used in a finished product authorised previously within the European Union. This approach is consistent with the definition of new active substance in the Notice to Applicants, Volume 2A, Chapter 1, Annex I: a chemical (…) substance not previously authorised as a medicinal product in the European Union. This guideline is not applicable to herbal, biological, biotechnological products, radiopharmaceuticals and radiolabelled products. The guideline does not apply to contents of submissions during the clinical research stages of drug development.
Nevertheless, the development principles presented in this guideline are important to consider during the investigational stages.