EP0840630B1 — Patient controlled drug delivery device

USPTO Abstract

A delivery device for patient-controlled infusion of a medicament (6), the delivery device comprising a reservoir (2) for the medicament (6) and a pump (4) having a predetermined delivery dose which is capable of displacing the medicament from the reservoir (2) and delivering it to a patient, wherein the pump (4) comprises a pumping means (14), a first conduit (10), capable of restricting flow rate, chosen in conjunction with the delivery dose of the pumping means (14) to define a predetermined maximum dosage rate, said conduit (10) connecting the reservoir (2) to a pumping means (14), a one-way valve (18) in fluid communication with the first conduit (10) and the pumping means (14) which permits medicament flow into the pumping means (14) but prevents reverse flow, a controlling means (32), and a second conduit (28) extending from the pumping means and having a distal end (30) through which, the medicament may be released, wherein the controlling means (32), (a) is in fluid communication with the pumping means (12) and the second conduit (28); (b) opens when pressure within the dose chamber (12) exceeds a predetermined minimum opening pressure for the controlling means (32); and, (c) is adapted to prevent the reverse flow of medicament and air into the pumping means.