| abstract |
Medical devices such as stents, stent grafts, and balloon catheters include an exterior surface, an intermediate layer overlying the exterior surface, and a coating layer overlying the intermediate layer, wherein the intermediate layer comprises a poly(p xylylene); and the coating layer comprises a hydrophobic therapeutic agent and at least one additive. The intermediate layer may be a parylene. The therapeutic agent may include paclitaxel, rapamycin, or combinations thereof. The intermediate layer may affect the release kinetics of the drug from the balloon, the crystallinity of the drug layer, the surface morphology of the coating and particle shape, the particle size of drug of a therapeutic layer in the coating layer, or may release a micron layer of parylene with the drug to prohibit washout by the blood stream after delivery. For example, the effects caused by the intermediate layer may increase the retention time and amount of therapeutic agent in tissue. |