Extractables and Leachables (E&L) testing is an essential safety evaluation that focuses on the chemicals that could migrate from the container closure system, medical devices, or manufacturing equipment into the drug product. "Extractables" are compounds that can be pulled out of a material under aggressive laboratory conditions (using solvents and heat), while "Leachables" are the compounds that actually migrate into the drug under normal storage conditions.

These studies are vital because many plastics, rubbers, and adhesives used in pharmaceutical packaging contain antioxidants, plasticizers, and stabilizers that could be toxic or interact with the drug. Analytical labs use a "non-targeted" screening approach, employing multiple techniques like GC-MS, LC-MS, and ICP-OES to identify any unknown chemical species. To see how specialized E&L services are integrated into the wider testing ecosystem, the Pharmaceutical Analytical Testing Outsourcing Market documentation offers a technical breakdown.

The data from an E&L study is used to perform a toxicological risk assessment. If a leachable is found at a concentration above the "Safety Concern Threshold" (SCT), the manufacturer must prove that it does not pose a risk to the patient. Because this testing requires specialized chemical libraries and high-resolution mass spectrometry, it is almost exclusively outsourced to laboratories that specialize in material science and trace-level chemical analysis. This ensures that the final drug product is not only effective but also free from potentially harmful contaminants.