Assessment of the chemical risk factor for application of artificial cardiac pacemakers equipped with a head made of thermoplastic polyurethane compound

For the purpose of improving the technology of manufacturing artificial cardiac pacemaker heads (connector blocks) (ACPHs), the traditional PEO-113K epoxy compound (produced by the St. Petersburg State Institute of Technology) was replaced by polyurethane (PU) Estate 58144 compound from Lubrizol (Germany) on the basis of 4,4-methylene diphenyl diisocyanate, 1,4-butanediol, and polytetramethylene oxide. To assess the safety of using ACPHs made of thermoplastic PU, sanitary chemical studies of products made in accordance with the technological regulations and ACPHs processed in the accelerated aging regime in Ringer–Locke solution at 80°C for 1785 h, which simulates a long stay (7.5 years) in the body, were performed. It was proved that potentially hazardous substances (the components of PU composition, functional and technological additives, impurities in raw materials, and products of their transformation that were analyzed by chromatographic and integral methods were absent in the water extracts from ACPHs. On the basis of the gas chromatography/mass spectrometry method, admixtures of compounds that can be attributed to oligomers of polytetramethylene oxide, which is one of the components of the polyurethane compound, were detected among the products of migration. Similar or identical values of the registered parameters of initial ACPHs and ACPHs processed in the accelerated aging regime indicate that the properties of ACPHs remain almost the same even after their processing in the accelerated aging regime simulating a long stay in body. As a result of toxicological studies, the biocompatibility of ACPHs made of PU with the body was proved. Histological examination of the area of ACPH implantation showed that the tissue reaction to the implantation was weaker than that to the control implantation of a sample made of NS-3 medical glass (GOST 19808-86). The possibility of using plastic Estane 58144 PU from Lubrizol (Germany) for ACPH production was substantiated as a method to significantly reduce the time of the technological process of manufacturing both ACPHs and pacemakers as a whole.