Surface crystallization of rapamycin on stents using a temperature induced process.

Metallic drug eluting stents (DES) are usually prepared by coating with a drug-polymer matrix as a rate controlling diffusion barrier. However, coating materials may display numerous problems, thus carrier-free DES are desired, yet releasing drug over long period of time. For this, we are reporting a novel temperature induced (TI) crystallization process for coating rapamycin on stents. Rapamycin crystals with a defined morphology and target drug load were applied from supersaturated solution. This method enables fabrication of controllable and homogeneous crystalline coatings on stent scaffolds and allowing the drug to release for several weeks.