Patent ID: 8323267

Claim:
An implantable therapeutic substance infusion device comprising: a therapeutic substance reservoir; control electronics operably connected to a power source; a bolus pump operably connected to the power source and the control electronics, the bolus pump further operably connected to the reservoir and configured to pump a therapeutic substance from the therapeutic substance reservoir in a downstream direction from the bolus pump to an infusion port in response to a pump signal received from the control electronics; a passive check valve located in a fluid pathway between the infusion port and the bolus pump, the passive check valve comprising a normally closed valve that opens in response to fluidic pressure generated by operation of the bolus pump; and an active check valve located in the fluid pathway between the passive check valve and the infusion port, wherein the active check valve comprises a normally closed valve that opens in response to an open signal from the control electronics, wherein fluid pressure on an upstream side of the active check valve increases the energy required to open the active check valve, and wherein fluid flow in the downstream direction through the active check valve is prevented when the active check valve is closed.