Patent ID: 8702682

Claim:
A medical device comprising a therapeutic-agent-containing region, a shrinkable and swellable barrier layer having an aperture disposed over the therapeutic-agent-containing region wherein the aperture increases in size when the barrier layer shrinks and decreases in size when the barrier layer swells, a piezoelectric region, a first conductive region disposed on a first surface of the piezoelectric region and a second conductive region disposed on a second surface of the piezoelectric region, wherein said first and second conductive regions are not in contact with one another, wherein when said device is administered to a subject and said piezoelectric region is subjected to mechanical stress, a voltage is created between the first and second conductive regions, wherein the barrier layer shrinks and the aperture is increased in size when the voltage is created, thereby initiating or increasing a rate of release of therapeutic agent from said therapeutic-agent-containing region into the subject.