A team of scientists from the New Jersey Center for Biomaterials and the Johnson & Johnson Sterility Assurance Group are finalizing a seminal publication, describing a comparison of 4 industrially relevant sterilization methods for medical implants. As part of a successful commercialization strategy, the selection of a suitable method for the FDA-required terminal sterilization of the implant is a critical task. All currently known sterilization methods can adversely affect the physicochemical properties of the polymers used as implant components. This study explores the effects of different sterilization modalities (ethylene oxide (EO), vaporized hydrogen peroxide (VHP), gamma (γ) radiation, and electron beam (E-beam)) on the chemical, structural and morphological properties of polymers with ether, carbonate, carboxylic acid, amide and ester functionalities using a family of poly(ethylene glycol) (PEG) containing tyrosine-derived polycarbonates (TyrPCs) as model compounds. Test polymers were selected to include slow, medium, fast and ultra-fast degrading polymers, representing a series of materials with increasing sensitivity to moisture, temperature, a radiation. Each of the sterilization modalities affected the tested polymers differently and no single sterilization technique emerged as being universally applicable for all test samples. This study illuminates the critical importance of considering the chemical composition of the polymer when selecting a sterilization method, and provides suggested conditions for each of the tested sterilization methods.
Pictured is the study's first author, Divya Bhatnagar, PhD.