In one aspect, a medical device has a first configuration and a second configuration, a reservoir containing a therapeutic agent, and a barrier layer disposed over the reservoir, wherein the barrier layer comprises an inorganic material. In another aspect, a medical device has a reservoir containing a therapeutic agent, a barrier layer disposed over the reservoir, wherein the barrier layer comprises an inorganic material, and a swellable material disposed between the barrier layer and a surface of the medical device, wherein the swellable material is a material that swells upon exposure to an aqueous environment. In yet another aspect, a medical device has a multi-layered coating having alternating reservoir layers and barrier layers, and a plurality of excavated regions penetrating through at least a partial thickness of the multi-layered coating. In yet another aspect, a medical device has a polymer layer comprising a block co-polymer, wherein the polymer layer contains a therapeutic agent, and a barrier layer disposed over the polymer layer, wherein the barrier layer comprises an inorganic material, and wherein the barrier layer has a plurality of discontinuities. Methods of forming coatings on medical devices and methods of delivering therapeutic agents to body sites are also disclosed.
