An unknown leachable species was detected by GC-MS analysis of an alkaline drug product (pH approximately 10.5) that was packaged in a novel self-contained plastic Blow Fill Seal (BFS) vial. Due to the high pH of the drug product formulation, it could not be stored in untreated glass vials. Treated glass vials are more expensive and are prone to delamination and particulate formation. The unknown leachable was not easily identified using mass spectral databases or by manual identification. Learn how transformative leachable species can arise from container and formulation interactions and get details about the study conducted to determine the identity and the origin of the leachable compound.