Patent ID: 8313759

Claim:
A therapeutic-agent-releasing medical device comprising: (a) an implantable or insertable medical device substrate; (b) a therapeutic agent; and (c) a release region in the form of a layer disposed over at least a portion of the implantable or insertable medical device substrate, said release region comprising (i) a first phase comprising a pair of miscible polymers that form a single polymer phase within the release region, said pair of miscible polymers being miscible with one another and selected from homopolymers, alternating copolymers, random copolymers and combinations thereof, and (ii) a second phase comprising an additional polymer which is not a block copolymer; wherein said first and second phases are in the same layer, wherein the volume of the first phase is less than the volume of the second phase, wherein said release region is a two-phase polymeric system, wherein the first phase forms cylindrical domains within the second phase or wherein the first and second domains form a lamellar structure, wherein said release region regulates the rate of release of said therapeutic agent from the medical device upon implantation or insertion of the device into a patient, and wherein said pair of miscible polymers is a pair of miscible polymers selected from the following: (a) poly(styrene-co-maleic anhydride)/poly(styrene-co-acrylonitrile), (b) poly(2,6-dimethyl-1,4-phenylene oxide)/polystyrene, (c) tetramethyl bisphenol A polycarbonate/polystyrene, (d) poly(ethylene oxide)/poly(methyl methacrylate), (e) polystyrene/poly(vinylmethyl ether), (f) poly(methyl methacrylate)/poly(styrene-co-acrylonitrile), and (g) poly(vinyl chloride)/poly(ethylene-co-vinyl acetate).