The development of novel biodegradable bifurcation stents for the sustainable release of anti-proliferative sirolimus

In this report, a balloon-expandable, biodegradable, drug-eluting bifurcation stent (DEBS) that provides a sustainable release of anti-proliferative sirolimus was developed. Biodegradable bifurcation stents, made of polycaprolactone, were first manufactured by injection molding and hot spot welding techniques. Various properties of the fabricated stents, including compression strengths, collapse pressures, and flow pattern in a circulation test, were characterized. The experimental results showed that biodegradable bifurcation stents exhibited comparable mechanical properties with those of metallic stents and superior flow behavior to that of metallic bifurcation stents deployed via the T And small Protrusion approach. Polylactide- polyglycolide (PLGA) copolymer and sirolimus were then dissolved in acetonitrile and coated onto the surface of the stents by a spray coating device. An elution method and a high performance liquid chromatography analysis were utilized to examine the in vitro release characteristics of sirolimus. Biodegradable bifurcation stents released high concentrations of sirolimus for more than 6 weeks, and the total period of drug release could be prolonged by increasing the drug loading of the PLGA/sirolimus coating layers. In addition, the eluted drug could effectively inhibit the proliferation of smooth muscle cells. The developed DEBS in this study may provide a promising strategy for the treatment of cardiovascular bifurcation lesions.