Evaluation of sterilisation techniques for 3D-printed implantable devices

Objectives: This article investigates the potential use of microwave (MW) radiation, UV-light and gamma radiation for the sterilisation of 3D-printed implantable devices prepared using poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA). Methods: Samples were sterilised using MW, UV and gamma radiation. Subsequently, the sterility of these samples was tested following the British Pharmacopeia test for sterility and controlled contamination test. Finally, sterilised samples were characterised (DSC, FTIR and drug release studies) to evaluate potential changes in their physicochemical properties during sterilisation. Key findings: MW-radiation failed the British Pharmacopeia test for sterility. UV-light did not pass the British Pharmacopoeia test for sterility, but it showed promising results for the controlled contamination test (bacterial-contamination reduction >99.9%). These techniques did not modify the physicochemical properties of PLA. On the other hand, samples treated with gamma radiation passed the British Pharmacopeia sterility tests. However, the Tg and mechanical properties of the resulting samples were affected by gamma radiation. It is important to note that none of the sterilisation methods investigated in this article resulted in any change in the in vitro release results. Conclusions: Only gamma radiation passed the British Pharmacopeia test for sterility. However, UV method showed potential and should be further investigated.