By Tim Sandle, Ph.D.
Published in: Pharmaceutical ONLINE
Published on: March 17, 2026
Extractables and leachables refer to various chemical compounds that can potentially migrate from packaging, devices, or manufacturing equipment into pharmaceutical products, posing safety risks. These are forms of impurity and can be organic impurities (process- and drug-related), inorganic impurities, or residual solvents. Different classifications for leachables and extractables exist, based on the potential harm they can cause to a patient (with mutagenic compounds in the highest class). Toxicological assessments need to consider both short- and long-term exposure.
A new draft guidance document from ICH, issued jointly with the European Medicines Agency,1 adopts the position that the assessment of these entities requires a holistic framework for risk evaluation, where risk concern should be foremost with patient safety and product quality. The ICH Q3E guidance focuses primarily on organic impurities, reserving elemental impurities for the companion document, ICH Q3D.2
Organic impurity is a general term for any unwanted carbon-based compound in a substance, such as pharmaceuticals. This can originate from raw materials, by-products, or degradation. In drugs, these also include intermediate compounds and isomers.
This article assesses the key points and requirements stemming from the guidance.
