Plastics are increasingly used as packaging materials for pharmaceuticals. However, diffusion of compounds in plastic into drugs may endanger patients' health. Regulatory authorities therefore demand detailed information about leachable compounds in plastics. Here we identify migrating components of a sterilization-resistant polyurethane (PUR) adhesive used in the primary packaging for an aqueous pharmaceutical. This identification is an essential first step for quantification and toxicological evaluation of the compounds.