Volume 3, Issue 2 (February 2006)
Cleanliness Testing and Identification of Residues on Polymer Medical Devices
Machining and cleaning are key processes in the manufacturing of metal, ceramic, and polymer medical devices. During these processes, the components and final devices are exposed to processing aids, handling equipment, cleaning agents, and packaging materials. Methods for the cleanliness testing of such potential residues are discussed in this paper. To assess the effectiveness of the total organic carbon (TOC) analysis for cleanliness testing, the recovery of organic residues was studied. Spiking tests showed that nonpolar hydrocarbons are not well extracted, neither by 1 h ultrasonication nor by 24 h refluxing in boiling water. This results in a very poor TOC recovery for mineral oil-like residues. Good recovery and a high sensitivity for such residues are obtained by solvent extraction following Fourier transform infrared spectroscopy (FTIR) analysis. Furthermore, extracted organic residues from machined polymer devices were identified by gas chromatography mass spectrometry (GC-MS). The results indicate that nonpolar polymers like ultra-high molecular weight polyethylene (UHMWPE) absorb hydrocarbons from mineral oil-based processing aids during machining.