Requirements for product purity, activity & shelf life dictate a very high standard for injectable drug packaging, particularly for highly active peptides and proteins. Packaging represents the first line of defense for all formulated pharmaceuticals. A good package protects the drug product from the outside world and vice versa. At the same time the package -- including the vial itself, stopper & seal materials -- must be fully compatible with the product, whether it is in solution or lyophilized. The FDA's requirements, as spelled out in the Guidance Container Closure Systems for Packaging Human Drugs & Biologics, discuss understanding levels of extractables/leachables & test methods related to these contaminants. The Guidance, which addresses evaluation of packaging systems for pharmaceutical and biopharmaceutical drug products, requires that each New Drug Application (NDA) contain enough information to demonstrate that a proposed package & its components are suitable for their intended use. It clearly indicates that all injectable products need to be evaluated for leachables, that may have migrated over the product shelf life during formal stability testing & beyond.