STRUCTURAL AND FUNCTIONAL STATE OF POLYMER COATING OF CORONARY STENTS AFTER EFFECTS OF THE ACCELERATED ELECTRONS FLOW

The article presents the results of investigation of the electron-beam processing effect by a stream of accelerated electrons on coronary stents with a drug coating. Experiments on the visualization of the polymer coating have been carried out, the parameters of the kinetics of the antiproliferative substance as a function of the radiation dose have been determined. Integrity of the drug-coated stents has been visually assessed by scanning electron microscopy and optical microscopy. The release kinetic have been evaluated by high-performance liquid chromatography method. It has been established that electron beam treatment by the stream of accelerated electrons leads to non-dangerous deformations of the coronary stents drug coating and to the increased yield of antiproliferative substance. Deformation sites of the elution system appear on the surface of the drug-eluting stents after electron-beam treatment by the stream of accelerated electrons at a dose of 1.5 and 3 Mrad. Prolonged diffusion of rapamycin from the treated stent creates concentrations greater than those when used untreated stent and depends on the radiation load in a dose-dependent manner. Stent electron beam treatment by the stream of accelerated electrons provides a high gradient of release of the antiproliferative substance from the elution system, exceeding that without treatment, for 10 days. Comparison of efficiency and safety allows us to consider the technology of electron beam processing as promising for the introduction into coronary stents production.