Patent ID: 8388678

Claim:
An implantable or insertable medical device comprising as components: (a) a substrate component comprising a depression that is at least partially filled with a therapeutic-agent-containing material that comprises a first therapeutic agent, and (b) a porous membrane component engaged with the substrate component and disposed over the depression such that it regulates transport of chemical species between the depression and the exterior of the device upon implantation or insertion of the device into a subject, wherein one component having an inner surface at least partially surrounds the other component having an outer surface, wherein the inner surface is engaged with the outer surface, wherein the components are formed from materials that have a different thermal expansion coefficient (TEC), wherein either (i) wherein both components expand upon heating such that the inner surface moves outwardly relative to the outer surface and such that the porous membrane component disengages from the substrate component upon heating the medical device and wherein the component that at least partially surrounds the other component is the component with the higher TEC or (ii) wherein both components contract upon cooling such that the inner surface moves outwardly relative to the outer surface and such that the porous membrane component disengages from the substrate component upon cooling the medical device and wherein the component that at least partially surrounds the other component is the component with the lower TEC, and wherein the porous membrane component is engaged with the substrate component upon implantation or insertion of the device into a subject.