Patent ID: 7766885

Claim:
A drug delivery system for implantation in a body for delivery of a liquid drug, the system comprising: a) an infusion housing defining a drug reservoir, a propellant chamber within the infusion housing and proximate the drug reservoir, wherein a positive pressure drug reservoir is created; b) the drug reservoir having a reservoir inlet for receiving the liquid drug and a reservoir outlet; c) a pump having a pump inlet and a pump outlet; d) a first fluid passageway operable to transfer the liquid drug between the reservoir outlet and the pump inlet; e) a first regulator having a first subchamber having a first regulator outlet and a second subchamber having a first regulator inlet; f) a first opening between the first subchamber and the second subchamber; g) a first diaphragm positioned in the second subchamber, the diaphragm moveable between an open position and a closed position to open and close the first opening, the diaphragm separating the second subchamber into a first middle chamber and a first lower chamber; h) a second fluid passageway operable to transfer the liquid drug between the pump outlet and the first regulator inlet, the first regulator inlet positioned in the first middle chamber; and i) a third fluid passageway between the lower chamber and the drug reservoir, whereby accidental flow from the reservoir to the first regulator outlet is prevented.