Biodegradable stents as a platform to drug loading

Abstract

Despite technical and mechanical improvement in coronary stents the incidence of restenosis caused by in-stent neointimal hyperplasia remains high. Oral administration of numerous pharmacological agents has failed to reduce restenosis after coronary stenting in humans, possibly owing to insufficient local drug concentration. Therefore, drug-eluting stents were developed as a vehicle for local drug administration. The authors developed a new drug-eluting polymer stent that is made of poly-l-lactic acid polymer mixed with tranilast, an anti-allergic drug that inhibits the migration and proliferation of vascular smooth muscle cells induced by platelet-derived growth factor and transforming growth factor->1. Polymer stents might be superior to polymer-coated metallic stents as local drug delivery stents in terms of biodegradation and the amount of loaded drug. Drug-mixed polymer stents can be loaded with a larger amount of drug than can drug-coated metallic stents because the polymer stent struts can contain the drug. Clinical application is required to assess the safety and efficacy of drug-eluting polymer stents against stent restenosis.

A review on biodegradable materials for cardiovascular stent application

“…PHB and their copolymers are extensively used in the biomedical devices such as bone plates, sutures, rivets staple screws, orthopedic pins and bone marrow scaffolds. The uniqueness of these polymers is that it can be either Knitted-type balloon expanded PGA dog coronary artery [73] Knitted-type balloon expanded PGA pig coronary artery [74][75] Diamond braided self-expanded PLLA dog femoral [76] Film -PCL/(D, L)PLA porcine carotid [77] Tubular coil balloon PLLA-PCL rabbit carotid arteries [78] Coil stent self-expanded PLLA human coronary [75] Drug eluting thermal expanded PLLA pig coronary [76] blended or co-polymerized, and tailor made to achieve the desired properties. The crystallinity and mechanical properties of P (HB-HV) can be adjusted by varying the ratio of the respective monomers.…”

Iron and iron-based alloys for temporary cardiovascular applications

“…The two main materials used in biodegradable stents are polymers and metals. In comparison to polymer biodegradable stents which have demonstrated some limitations such as local inflammation, radiolucency, limited mechanical performance and early recoil post implantation [2,3], metal stents are remarkable since they have the potential to perform similarly to traditional stainless steel metal stents.…”

In vitro homogeneous and heterogeneous degradation of poly(ϵ‐caprolactone/polyethylene glycol/L‐lactide): The absence of autocatalysis and the role of enzymes

“…Research over the last thirty years has led to their extensive application in surgery and pharmacology, including degradable sutures, 1 degradable bone screws, pins and plates, [2][3][4] and drug delivery carriers. 5,6 However, with the emergence of new applications, such as drugeluting endovascular stents 7,8 and templates for tissue regeneration, 9,10 new biodegradable polymers displaying both a wide range of degradation rates and a combination of various properties have generated enormous interest in biomaterials research.…”