Osmotic pump delivery system with pre-hydrated membrane(s) and/or primable catheter

Abstract

An implantable osmotic pump system includes a pre-hydrated semipermeable membrane to reduce the time interval between implantation of the system into the patient and full operation of the pump system. The semipermeable membrane is maintained in a hydrated state prior to implantation by fluid contact with a saline solution maintained in a saturated state by a salt tablet. As the differential osmotic pressure across the hydrated semipermeable membrane is negligible as the saline concentration on both sides of the membrane is the same, the pump system does not operate and does not infuse the pharmaceutical agent as long as this osmotic equipotential state is maintained. When the saturated saline solution is removed from fluid contact with the semipermeable membrane and the system is implanted in a patient, the osmotic pressure differential across the semipermeable membrane increases, thereby causing the pump to immediately begin operation at or near its intended and designed steady state infusion rate. To further decrease the delay between implantation and effusion of a pharmaceutical agent from the system, the infusion lumen of an attached catheter may be at least partially flushed with the same or a different pharmaceutical agent as is loaded in the pharmaceutical agent compartment of the pump system.