 Dr. Jerry Nelson Nelson Laboratories Chief Science Officer Visit Website |
Jerry R. Nelson, Laboratory Director at Nelson Laboratories, has a PhD in microbiology and immunology from the University of Utah. He is a member of numerous standards-writing committees and associations, including the New York Academy of Sciences, American Society for Quality, Parenteral Drug Association, American Society of Testing and Materials, Association for Advancement of Medical Instrumentation, Society for Pharmaceutical Engineering, and the American Society for Microbiology. In addition to having published dozens of articles, he is also an adjunct professor of bioengineering at the University of Utah and an adjunct assistant professor of microbiology at Brigham Young University. Jerry was named by MPMN's sister publication, MD+DI, as one of the Top 100 Notable Individuals in the medical device industry.
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Sterilization and Biocompatibility Q&A
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Do you have any suggestion for sterilizing a bioabsorbable stent made from polylactic acid (PLA) material? It is better to sterilize it at room temperature without wetting and gassing the material. We tried sterilizing it in EtO at room temperature, but the stent became deformed. The literature suggests the use of E-beam or gamma irradiation. Which one do you prefer?Answered August 3rd, 2011 by Expert:If the stent is metal or has metal in it, I would prefer gamma radiation because the E-beam method can cause ‘shadowing.’ By ‘shadowing,’ I mean that the E-beam bounces off metal objects and does not penetrate to the other side well if they are not sterilized from both sides. E-beam sterilization also needs additional samples to dose-map the sterilization process. Gamma is a better sterilization method, in my opinion. It ‘radiates’ from all sides and provides very good sterilization assurance.
Because the stent would most likely have a very low bioburden, a low-dose sterilization process could be performed if the bioburden is consistent. However, according to TIR17, polylactides are poor to good with regard to radiation stability. The best option may be to irradiate using both sources and see how the functionality testing comes out.