A therapeutic-agent release region is described, which comprises: (i) a first phase comprising a plurality of miscible polymers that are miscible with one another and (ii) a second phase comprising an additional polymer, which can be immiscible with any or all of the plurality of miscible polymers or a blend of the miscible polymers. Also described is a therapeutic-agent-releasing medical device, which comprises: (a) an implantable or insertable medical device substrate (b) the above release region, disposed over at least a portion of the implantable or insertable medical device substrate, and (c) a therapeutic agent. The release region regulates the rate of release of the therapeutic agent from the medical device upon implantation or insertion of the device into a patient. Also described are methods for making an implantable or insertable medical device, for administering a therapeutic agent to a patient, and for modulating the release rate of a therapeutic agent.
