Extractables and Leachables in Pharmaceutical Products: Potential Adverse Effects and Toxicological Risk Assessment

During production, storage, and administration, drug products (and their intermediates) are in contact with many different types of materials, which include manufacturing components, container closure systems, and administration materials; therefore, there is a potential for their interactions and the introduction of leachables. The presence of leachables may impact key quality attributes of drug products in many ways. These include potential alterations in drug product stability, resulting in a reduced shelf-life, compromised drug product efficacy due to degradation or inactivation of active pharmaceutical ingredients, and impaired drug product physical acceptability due to precipitation, discolouration and/or change in odour or flavour. Moreover, some leachables may be inherently toxic (mutagenic, carcinogenic, immunogenic, etc.) posing direct risks to patient safety. Comprehensive toxicological evaluation of extractables and leachables is therefore essential. Documented cases demonstrate that presence of leachables can lead to serious and clinically significant adverse effects, underscoring the importance of their identification, quantification, and toxicological assessment during pharmaceutical development. This paper provides an overview of the toxicological limits used in the analyses of extractables and leachables and illustrates how they are translated into analytical limits. It also outlines the workflow for toxicological risk assessment of extractables and/or leachables, including evaluations of mutagenicity and other relevant toxicological endpoints. Special attention is given to the interpretation of the draft ICH Q3E guideline, which represents a pivotal development in harmonizing global expectations for extractables and leachables safety assessments. Understanding and correctly applying ICH Q3E is crucial, as it will shape regulatory strategies, analytical approaches, and risk management practices across the pharmaceutical industry. The paper concludes by highlighting emerging challenges that demand sustained advancements in both scientific methodologies and regulatory frameworks.