Polymer membranes for continuous analyte sensors

• US 8,583,204 B2
• Filed: 03/05/2010
• Issued: 11/12/2013
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Boock, Robert, Rixman, Monica A., Zhang, Huashi, Estes, Michael J., Lawrence, Kristina
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US12/718,299
• Publication Number:
  US 20100280341A1
• Time in Patent Office: 1,348 Days
• Field of Search: 600/309, 600345-366
• US Class Current: 600/345
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/40 Semi-permeable membranes or partitions

Abstract

Devices and methods are described for providing continuous measurement of an analyte concentration. In some embodiments, the device has a sensing mechanism and a sensing membrane that includes at least one surface-active group-containing polymer and that is located over the sensing mechanism. The sensing membrane may have a bioprotective layer configured to substantially block the effect and/or influence of non-constant noise-causing species.

Claims

1. A device for continuous measurement of an analyte concentration, the device comprising:

a sensor configured to continuously measure a signal associated with an analyte concentration in a host; and

a membrane located over the sensor, wherein the membrane comprises a polyurethane and a hydrophilic portion;

wherein the device is configured to provide, at analyte concentrations of from about 40 mg/dL to about 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of no more than 8% over a sensor session of at least about 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

2. The device of claim 1, wherein the sensor session is at least about 5 days.

3. The device of claim 1, wherein the sensor session is at least about 6 days.

4. The device of claim 1, wherein the sensor session is at least about 7 days.

5. The device of claim 1, wherein the sensor session is at least about 10 days.

6. The device of claim 1, wherein the membrane comprises a copolymer comprising a silicone segment.

7. The device of claim 1, wherein the mean absolute relative difference is no more than 7% over the sensor session.

8. The device of claim 1, wherein the membrane comprises an enzyme configured to react with the analyte.

9. The device of claim 1, wherein the membrane comprises a copolymer comprising a fluorocarbon segment.

10. The device of claim 1, wherein the membrane comprises a polycarbonate segment.

11. The sensor of claim 1, wherein the sensor is configured for transcutaneous implantation into a host.

12. The sensor of claim 1, wherein the sensor comprises a first portion and second portion, wherein the first portion is adapted for insertion under the host'"'"'s skin and the second portion is adapted to reside ex vivo.

13. The sensor of claim 1, wherein the sensor is configured to reside in subcutaneous tissue.

14. The sensor of claim 1, wherein the sensor is configured to have a mean absolute difference of no more than 7 mg/dL at an analyte concentration range of from 40 mg/dL to 80 mg/dL.

15. The sensor of claim 1, wherein the host is diabetic.

16. The sensor of claim 1, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 30 mg/dL while immersed in a solution comprising about 3 mg/dL acetaminophen.

17. The sensor of claim 1, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 17 mg/dL while immersed in a solution comprising about 6 mg/dL ascorbic acid.

18. The sensor of claim 1, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 25 mg/dL while immersed in a solution comprising about 6 mg/dL uric acid.

19. A system for continuous measurement of an analyte concentration, the system comprising:

a sensor comprising;

a sensing region configured to continuously produce sensor data associated with an analyte concentration in a host; and

a membrane located over the sensing region, wherein the membrane comprises a polyurethane and a hydrophilic portion;

a processor configured to process continuous sensor data; and

a user interface configured to display information associated with continuous sensor data;

wherein the sensor is configured to provide, at analyte concentrations of from about 40 mg/dL to about 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of no more than 8% over a sensor session of at least about 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

20. The system of claim 19, wherein the sensor session is at least about 5 days.

21. The system of claim 19, wherein the sensor session is at least about 6 days.

22. The system of claim 19, wherein the sensor session is at least about 7 days.

23. The system of claim 19, wherein the sensor session is at least about 10 days.

24. The system of claim 19, wherein the mean absolute relative difference is no more than 7% over the sensor session.

25. The system of claim 19, wherein the membrane comprises an enzyme configured to react with the analyte.

26. The system of claim 19, wherein the membrane comprises a copolymer comprising a fluorocarbon segment.

27. The system of claim 19, wherein the membrane comprises a copolymer comprising a silicone segment.

28. The system of claim 19, wherein the membrane comprises a polycarbonate segment.

29. The system of claim 19, wherein the sensor is configured for transcutaneous implantation into a host.

30. The system of claim 19, wherein the sensor comprises a first portion and second portion, wherein the first portion is adapted for insertion under the host'"'"'s skin and the second portion is adapted to reside ex vivo.

31. The system of claim 19, wherein the sensor is configured to reside in subcutaneous tissue.

32. The system of claim 19, wherein the sensor is configured to have a mean absolute difference of no more than 7 mg/dL at an analyte concentration range of from 40 mg/dL to 80 mg/dL.

33. The system of claim 19, wherein the host is diabetic.

34. The system of claim 19, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 30 mg/dL while immersed in a solution comprising about 3 mg/dL acetaminophen.

35. The system of claim 19, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 17 mg/dL while immersed in a solution comprising about 6 mg/dL ascorbic acid.

36. The system of claim 19, wherein the sensor is configured to exhibit no more than an equivalent glucose signal of no more than about 25 mg/dL while immersed in a solution comprising about 6 mg/dL uric acid.