[Pharmacodynamics of China-made rapamycin-polylactide-co-glycolide peripheral arterial eluting stent membrane: in vitro experiment].

Objective: To evaluate the property and drug releasing pattern of the China-made rapamycin-polylactide-co-glycolide (PLGA) peripheral arterial eluting stent membrane.

Methods: Rapamycin was put into PLGA so as to made rapamycin-PLGA complex. Twelve nickel-titanium self-expanding stents were dipped into the complex to make drug-eluting stents. Somatotype microscope was used to observe the macro-form of the surface of the eluting membrane, and atom force microscope was used to analyzing the three-dimensional appearance and surface roughness of the membrane. The stents were put into fluid with platelets to observe the form of platelets blood compatibility by scanning electron microscopy. The extra degradation of the coating layer, by putting the stents into a simulation system of internal environment. High efficacy liquid chromatography was used to study the pharmacokinetics of the stents. Standard curve and stimulative curve, and drug release curve of multiple stents were drawn and analyzed.

Results: The membranes of all 12 stents had smooth surfaces and regular thickness and no membrane falling-off was observed. The platelets on the surfaces of the stents were inactivated and the number of the platelets adhering to the surfaces of the stents were reduced obviously in comparison with the blank control. PLGA degraded by 20% within 2 weeks and then the degradation speed accelerated until complete degradation occurred within 6 weeks, and the drug releasing lasted more than 50 days. The percentage of accumulative drug release was 11.02% in 24 hours, 41.23% in 9 days, and 79.44% in 30 days.

Conclusion: Smooth and even, and capable of controlling the drug release, rapamycin-PLGA peripheral arterial eluting stent membrane coating has the potential clinical value in preventing in-stent stenosis.