Comparison of the optical and mechanical properties of plastics before and after ethylene oxide sterilization

Ethylene oxide (EO) sterilization is the most used sterilization method for disposable medical devices. Its popularity is based on the fact that it can be executed on industrial scale on full pallets of packed products and the fact that many materials are compatible with this sterilization technique.

This article describes an introduction to EO as a sterilization technique and further studies on the compatibility of medical grade plastics with EO sterilization.

Fourteen different healthcare polymer grades have been exposed to EO. This includes frequently used polyethylenes, polypropylenes, polyesters, and polycarbonates. Their mechanical and optical properties before and after exposure with EO were determined.

After both the statistical analysis and a comparison with the accuracy of the measurement system, it can be concluded that all tested polymers retained their mechanical properties as measured by tensile and Izod impact testing after 1 sterilization cycle. Optical measurements showed that only 2 of the polymer grades had a minor discoloration, while all other materials had a very limited color change.

It has been shown that all families of plastics typically used in disposable medical products can be sterilized with EO without significant change in properties as determined on standardized test specimen.