Following the completion of the extraction studies on the container closure system, the development team must begin the evaluation of leachables in the final drug product.    Ideally, the leachables study should be performed as part of the self-life stability study on three separate production lots.    When designing the leachables study, the development team needs to consider including a control.   

A proper control is critical for a successful leachables study.   The main purpose of the control is to allow for a quick determination if unknowns are leachables or drug product degradation products.  Leachables methods are usually orders of magnitude more sensitive than the degradation products methods and thus will detect degradation products and impurities that are well below specifications.    Therefore detecting new drug product degradation products during leachables analysis is common.

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