Implantable medication delivery device using pressure regulator

• US 20050273083A1
• Filed: 08/12/2005
• Published: 12/08/2005
• Est. Priority Date: 03/27/2003
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Infusion Systems, LLC
• Inventors: Das, Stephen D., Lebel, Ronald J.
• Granted Patent: US 7,510,552 B2
• Time in Patent Office: Days
• US Class Current: 604/891.100
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3351 Controlling upstream pump pressure
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/16813 by controlling the degree of opening of the flow line
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/16881 Regulating valves on-off valves, e.g. clamps A61M39/28
• CPC Class Codes: G05D 7/0688 by combined action on throttling means and flow sources G05D7/0694 takes precedence

Abstract

An implantable medication delivery apparatus including a flow path coupling a medication reservoir to a device outlet port where the flow path includes a regulator means for limiting the magnitude of pressure transferred downstream from the medication reservoir. The regulator means is configured to respond to the reservoir pressure exceeding a certain threshold for closing a valve located downstream from the reservoir. The valve closure functions to isolate the device outlet port from further reservoir pressure increases which otherwise could induce unintended medication flow from the device outlet port.

Claims

1. An implantable medication delivery device comprising;

an implantable housing having a fill port and an outlet port;

a medication reservoir in said housing in communication with said fill port; and

a flow path in said housing coupling said reservoir to said outlet port, said flow path including pressure regulator means operable to isolate said reservoir from said outlet port in response to an increase in reservoir pressure in excess of a threshold level.

2. The device of claim 1 wherein said pressure regulator means includes a flow controller responsive to said reservoir pressure increasing above said threshold level for isolating said reservoir pressure from said outlet port.

3. The device of claim 1 wherein said pressure regulator means includes a regulator medication chamber for receiving medication from said reservoir for delivery to said outlet port;

and

a flow controller responsive to pressure in said chamber exceeding a threshold level for closing said flow path downstream from said reservoir and upstream form said chamber.

4. The device of claim 3 further including means for pumping medication from said chamber to said outlet port.

5. The device of claim 1 wherein said pressure regulator means includes:

a pressure responsive element mounted for movement in response to a sufficient difference in first and second pressures respectively applied thereto; and

a flow control element coupled to said pressure responsive element for movement between an open position coupling said reservoir to said outlet port and a closed position isolating said reservoir from said outlet port.

6. The device of claim 5 wherein said pressure responsive element includes a bellows.

7. The device of claim 5 wherein said pressure responsive element includes a diaphragm.

8. The device of claim 5 wherein said first pressure is referenced to a substantially constant pressure within said housing.

9. The device of claim 5 wherein said second pressure is derived from the pressure in said medication reservoir.

10. The device of claim 5 further including a catheter coupled to said outlet port;

and wherein

said first pressure is referenced to a pressure derived from the distal end of said catheter.

11. A medication delivery device adapted for implantation in a patient'"'"'s body comprising:

an implantable housing having a fill port and an outlet port;

a reservoir in said housing for storing fluid medication from said fill port;

a flow path in said housing coupling said reservoir to said outlet port, said flow path including;

a normally open valve;

a medication chamber located downstream from said valve for receiving fluid medication from said reservoir; and

pressure responsive means operable to close said valve in response to pressure in said chamber exceeding a threshold level.

12. The delivery device of claim 11 wherein said flow path further includes a pump for pumping medication from said medication chamber to said outlet port.

13. The delivery device of claim 11 wherein said pressure responsive means includes an element mounted for movement in response to a differential between said medication chamber pressure and a reference pressure.

14. The delivery device of claim 13 wherein said reference pressure is derived from ambient pressure within a fixed volume chamber in said housing.

15. The delivery device of claim 13 wherein said reference pressure is derived from a site in said patient'"'"'s body spaced from said housing.

16. The delivery device of claim 13 including a catheter coupled to said outlet port for delivery medication to a patient'"'"'s body site;

and wherein said reference pressure is derived from said catheter.

17. The delivery device of claim 11 wherein said pressure responsive means comprises a bellows.

18. The delivery device of claim 11 wherein said pressure responsive means comprises a diaphragm.

19. A method of operating a medication delivery device to avoid overpressurization of a medication reservoir inducing unintended medication delivery from a device outlet port, said method comprising:

comparing the pressure in said medication reservoir to a threshold level; and

closing a normally open flow path coupling said reservoir to said outlet port in response to said reservoir pressure exceeding said threshold level.

20. A method of delivering fluid medication from a reservoir to a patient'"'"'s body site comprising:

providing a reservoir having a fill port; and

providing a flow path for transferring medication from said reservoir to an outlet port where said flow path includes a normally open valve, a medication chamber downstream from said valve, and a pressure responsive mechanism operable to close said valve in response to the pressure in said chamber exceeding a threshold level.

21. The method of claim 20 further including establishing a reference pressure level;

and

referencing said threshold level to said reference pressure level.

22. The method of claim 21 wherein said step of establishing a reference pressure level includes deriving a substantially constant pressure from a fixed volume chamber.

23. The method of claim 21 wherein said step of establishing a reference pressure level includes deriving said reference pressure level from proximate to said body site.

24. The method of claim 21 including a further step of coupling a catheter to said outlet port for transporting fluid medication to said body site;

and wherein

said step of establishing a reference pressure level includes deriving said reference pressure level from said catheter.