Patent ID: 8137315

Claim:
An apparatus for controlled release of drugs, the apparatus comprising a self-contained pump comprising: a reservoir; at least one outlet; a pumping mechanism comprising at least one piezoelectric actuator on at least one wall of the reservoir, wherein the at least one piezoelectric actuator comprises at least one selected from the group consisting of: (1) a helix around at least one side wall of the reservoir, (2) a double helix around at least one side wall of the reservoir, (3) at least two piezoelectric actuators on a bottom wall of the reservoir, (4) corner posts of a plurality of side walls of the reservoir, and (5) at least one piezoelectric actuator integrated with at least one of the bottom wall and a top wall of the reservoir; and a central core within the reservoir; whereby the pumping mechanism is for controlled compression of the reservoir to force a required volume of fluid in the reservoir through the at least one outlet, and whereby the central core extends between and seals with the top wall and the bottom wall of the reservoir, the central core being substantially rigid.