Among the various techniques of sterilization, e.g., ethylene oxide, steam, and gamma irradiation, the latter might be one of the most attractive for its safety aspects, versatility, and easy procedures for its applications in fields such as food, biopharmaceutical and medical device industries(1–4). Currently, gamma irradiation is the most common irradiation modality used for the sterilization of medical devices and biopharmaceutical products while two other irradiation modalities are emerging: electron beam and X-ray irradiation. Whatever the type of ionizing radiation used, it would modify the physical-mechanical-tribological and chemical properties of polymers. A three-level approach (i.e. molecular level, macromolecular level and material level) for investigation of multilayer films was used. The effects of three irradiation sources – X-rays, e-beam and 60Co-gamma on the physical, mechanical, and chemical properties of multilayer films have been studied thoroughly using different techniques.

Single use bags made up of PE/EVOH/PE multilayer film and commonly used in the biopharmaceutical field have been selected as a model. Different techniques were used to monitor changes in the material such as differential scanning calorimetry (DSC) in Figure 1a, Electron Spin Resonance (ESR) in Figure 1b and High Performance Liquid Chromatography (HPLC).

With PE multilayer film as a model, we show that, whatever the type of irradiation, thermal properties are not significantly changed, and, as per, physical and mechanical properties of this material are also expected to behave likely.