SILICONE BASED MEMBRANES FOR USE IN IMPLANTABLE GLUCOSE SENSORS

• US 20090287073A1
• Filed: 07/29/2009
• Published: 11/19/2009
• Est. Priority Date: 05/22/2002
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Boock, Robert, Rixman, Monica
• Granted Patent: US 8,064,977 B2
• Time in Patent Office: Days
• US Class Current: 600/365
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/46 containing polyether sequences
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

Membrane systems incorporating silicone polymers are described for use in implantable analyte sensors. Some layers of the membrane system may comprise a blend of a silicone polymer with a hydrophilic polymer, for example, a triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) polymer. Such polymeric blends provide for both high oxygen solubility and aqueous analyte solubility.

Claims

1. A membrane for use in an analyte sensor, comprising:

a silicone polymer; and

a poly(ethylene oxide) and poly(propylene oxide) co-polymer, wherein the membrane is adapted to permit diffusion of both the analyte and oxygen therethrough.

2. The membrane of claim 1, wherein the silicone polymer is a dimethyl-siloxane and methylhydrogen-siloxane copolymer.

3. The membrane of claim 2, wherein the silicone polymer comprises vinyl substituents.

4. The membrane of claim 1, wherein the copolymer comprises hydroxy substituents.

5. The membrane of claim 1, wherein the co-polymer is a triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) polymer.

6. The membrane of claim 1, wherein the co-polymer is a triblock poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) polymer.

7. The membrane of claim 1, wherein the analyte is glucose.

8. The membrane of claim 1, wherein at least a portion of the co-polymer is cross-linked.

9. The membrane of claim 1, wherein from about 5% w/w to about 30% w/w of the membrane is the co-polymer.

10. An implantable analyte sensor, comprising:

an enzyme layer comprising an enzyme; and

a bioprotective layer positioned between the enzyme layer and tissue adjacent to the sensor when implanted, wherein the bioprotective layer comprises a silicone polymer and a poly(ethylene oxide) and poly(propylene oxide) co-polymer.

11. The sensor of claim 10, further comprising a diffusion resistance layer positioned between the enzyme layer and the bioprotective layer.

12. The sensor of claim 11, wherein the diffusion resistance layer also comprises the silicone polymer and the poly(ethylene oxide) and poly(propylene oxide) co-polymer.

13. The sensor of claim 12, wherein a ratio of the silicone polymer to the co-polymer is different in the diffusion resistance layer than in the bioprotective layer.

14. The sensor of claim 10, further comprising a cell disruptive layer positioned between the bioprotective layer and tissue adjacent to the sensor when implanted.

15. The sensor of claim 10, wherein the silicone polymer is a dimethyl-siloxane and methylhydrogen-siloxane copolymer.

16. The sensor of claim 15, wherein the silicone polymer comprises vinyl substituents.

17. The sensor of claim 10, wherein the copolymer comprises hydroxy substituents.

18. The sensor of claim 10, wherein the co-polymer is a triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) polymer.

19. The sensor of claim 10, wherein the co-polymer is a triblock poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) polymer.

20. The sensor of claim 10, wherein the analyte is glucose.

21. The sensor of claim 10, wherein at least a portion of the co-polymer is cross-linked.

22. The sensor of claim 10, wherein from about 5% w/w to about 30% w/w of the bioprotective layer is the co-polymer.

23. The sensor of claim 10, wherein the enzyme layer also comprises the silicone polymer and the co-polymer.

24. The sensor of claim 23, wherein a ratio of the silicone polymer to the co-polymer is different in the enzyme layer than in the bioprotective layer.