Drug Eluting Stents Coated With Rapamycin Crystals for the Prevention of Restenosis and Biofilm Formation

Abstract

Restenosis and biofilm formation during coronary stent implantation were considered to increase the complications of cardiovascular disease. To prevent these dual problems, drug-eluting stents coated with crystallized drug-polymer mixtures (Rapamycin-Polyvinyl pyrrolidone) were developed and its efficacy was investigated in the present study. Single layer coating using seeding and crystallization of drug-polymer mixture on the stent surface were carried out for effective drug delivery at the target site. Efficacy of rapamycin release concentration from the coated drug-eluting stents for the prevention of restenosis using High performance liquid chromatography was determined. Antibacterial activity of the drug-eluting stents against biofilm organisms was simultaneously studied. High performance liquid chromatography established the efficiency of modified coating technique and controlled release of rapamycin from drug-polymer mixture. Antibacterial activity of drug-eluting stents showed maximum inhibitory zone of 31.3mm against Staphylococcus aureus for 2X crystallized rapamycin coated stents. SEM images of rapamycin coatings on the stents exhibits extremely large uniform and continuous layer of parallelogram shaped rapamycin crystals in drug loaded stents. The sustained release of drugs fulfilled the primary aim of developing an anti-infective method for post-operative infection caused by biofilm organisms and also the prevention of restenosis.