Compatibility of Polyvinyl Chloride (PVC) Medical Devices and Other Polymeric Materials with Reactive Ion Etching (RIE) and Inductively Couple Plasma (ICP) Sterilization Using a Quality by Design (QbD) Approach

Purpose The sterilization process for medical devices is an important step due to microbiological quality requirements of polymeric products. Irradiation and ethylene oxide sterilizations, traditional techniques, may compromise safety and efficacy of medical devices due to oxidation/alkylation or due to the presence of residues in polymeric materials. Alternatively, reactive Ion etching (RIE) and inductively coupled plasma (ICP) may be used for this purpose; however, the compatibility of polymeric materials with these processes and their lethality must be addressed. Methods We assessed herein chemical and biological modifications in polymeric materials after an RIE and ICP sterilization process, using photoacoustic Fourier transform infrared spectroscopy (FTIR-PAS), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), surface profilometry analysis (SPA), and in vitro agar diffusion cytotoxicity. In addition, a factorial design was adopted to study lethality in PVC catheters, evaluating the influence of sterilization mode (RIE or ICP), radio frequency power (from 100 to 300 W), hydrogen peroxide concentration (from 0 to 20%), and internal lumen diameter of PVC catheters (from 1 to 7 mm) in D-values. Results RIE and ICP sterilization using a mixture of O-2 and H2O2 (80 and 20%, respectively) have caused chemical modifications in all polymers, however, without increasing in vitro cytotoxicity. Based on factorial design results, we proposed mathematical models to predict the D-values (time to kill 90%-or 1 log reduction-of microbial load) as a function of H2O2 concentration and internal lumen diameter of catheters. Conclusions Quality by design approach allow one to develop a rational sterilization process considering the required time for sterilization, concentration of H2O2, and the internal lumen diameter of catheters.