Device and method for determining analyte levels

• US 8,527,025 B1
• Filed: 11/22/1999
• Issued: 09/03/2013
• Est. Priority Date: 03/04/1997
• Status: Expired due to Fees

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Shults, Mark C., Updike, Stuart J., Rhodes, Rathbun K.
• Primary Examiner(s): Nasser, Robert L
• Application Number:
  US09/447,227
• Time in Patent Office: 5,034 Days
• Field of Search: 600/309, 600345-347, 600365-366, 600/373, 600/573, 600/582, 600/584, 424422-425
• US Class Current: 600/347
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• 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 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

Devices and methods for determining analyte levels are described. The devices and methods allow for the implantation of analyte-monitoring devices, such as glucose monitoring devices, that result in the delivery of a dependable flow of blood to deliver sample to the implanted device. The devices comprise a unique microarchitectural arrangement in the sensor region that allows accurate data to be obtained over long periods of time.

Claims

1. A device for measuring a glucose concentration in a host, the device comprising:

a sensor operably connected to an electronic circuit and configured to continuously measure a signal associated with a glucose concentration in a host; and

a membrane located over at least a portion of the sensor, wherein the membrane is configured to control a flux of oxygen and glucose, wherein the membrane is configured to use oxygen from a biological fluid surrounding the membrane to catalyze a reaction of glucose and oxygen, and wherein the membrane comprises a silicone-containing polymer;

wherein the device is capable of exhibiting, at a glucose concentration of 400 mg/dL, no more than a 10% drop in sensor output over a range of pO₂ from about 150 mm Hg down to about 30 mm Hg.

2. The device of claim 1, wherein the membrane comprises a layer comprising an enzyme.

3. The device of claim 1, wherein the membrane is monolithic and homogeneous.

4. The device of claim 1, wherein the membrane is monolithic and heterogeneous.

5. The device of claim 1, wherein the membrane has a thickness of from about 15 microns to about 60 microns.

6. The device of claim 1, wherein at least 95% of glucose concentration values measured by the device are within 25% of corresponding values determined by analysis of blood over a useful life of the device.

7. The device of claim 6, wherein the useful life of the device is at least 3 days.

8. The device of claim 1, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to about 500 mg/dL.

9. The device of claim 1, wherein the membrane comprises an interference layer.

10. The device of claim 6, wherein the useful life of the device is at least 1 day.

11. The device of claim 6, wherein the useful life of the device is at least 2 days.

12. The device of claim 6, wherein the useful life of the device is at least 4 days.

13. The device of claim 6, wherein the useful life of the device is at least 5 days.

14. The device of claim 6, wherein the useful life of the device is at least 6 days.

15. The device of claim 6, wherein the useful life of the device is at least 7 days.

16. The device of claim 6, wherein the useful life of the device is at least 10 days.

17. The device of claim 6, wherein the useful life is defined by a period of time after stabilization of the device.

18. The device of claim 17, wherein the useful life is further defined by a period of time during which stability of calibration is maintained.

19. The device of claim 1, wherein the membrane comprises a urethane polymer or polyurethane.

20. The device of claim 19, wherein the urethane polymer or polyurethane comprises a polycarbonate-polyurethane backbone.

21. The device of claim 1, wherein the membrane comprises a cross-linked polymer.

22. The device of claim 1, wherein the device is capable of obtaining a calibration stability that is maintained within 10% for one week.

23. The device of claim 1, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to at least 400 mg/dL.

24. The device of claim 1, wherein the device is capable of attaining a 90% time response to a 100 mg/dL glucose concentration step in less than 5 minutes.

25. The device of claim 1, wherein the device is configured to reduce or eliminate motion artifact.

26. A device for measuring a glucose concentration in a host, the device comprising:

a sensor operably connected to an electronic circuit and configured to continuously measure a signal associated with a glucose concentration in a host; and

a membrane located over at least a portion of the sensor, wherein the membrane is configured to control a flux of oxygen and glucose;

wherein at least 95% of glucose concentration values measured by the device are within 25% of corresponding values determined by analysis of blood over a time period of at least two days.

27. The device of claim 26, wherein the membrane comprises a layer comprising an enzyme.

28. The device of claim 26, wherein the membrane is monolithic and homogeneous.

29. The device of claim 26, wherein the membrane is monolithic and heterogeneous.

30. The device of claim 26, wherein the membrane has a thickness of from about 15 microns to about 60 microns.

31. The device of claim 26, wherein the time period is at least 3 days. device is at least 3 days.

32. The device of claim 26, wherein the device is capable of exhibiting, at a glucose concentration of 400 mg/dL, no more than a 10% drop in sensor output over a range of pO₂ from about 150 mm Hg down to about 30 mm Hg.

33. The device of claim 26, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to about 500 mg/dL.

34. The device of claim 26, wherein the membrane comprises an interference layer.

35. The device of claim 26, wherein the time period is at least 1 day.

36. The device of claim 27, wherein the time period is at least 2 days.

37. The device of claim 28, wherein the time period is at least 4 days.

38. The device of claim 29, wherein the time period is at least 5 days.

39. The device of claim 30, wherein the time period is at least 6 days.

40. The device of claim 31, wherein the time period is at least 7 days.

41. The device of claim 32, wherein the time period is at least 10 days.

42. The device of claim 33, wherein the time period is defined by a period of time after stabilization of the device.

43. The device of claim 42, wherein the time period is further defined by a period of time during which stability of calibration is maintained.

44. The device of claim 34, wherein the time period is defined by a period of time after stabilization of the device.

45. The device of claim 44, wherein the time period is further defined by a period of time during which stability of calibration is maintained.

46. The device of claim 26, wherein the membrane comprises a urethane polymer or polyurethane.

47. The device of claim 46, wherein the urethane polymer or polyurethane comprises a polycarbonate-polyurethane backbone.

48. The device of claim 26, wherein the membrane comprises a cross-linked polymer.

49. The device of claim 26, wherein the device is capable of obtaining a calibration stability that is maintained within 10% for one week.

50. The device of claim 26, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to at least 400 mg/dL.

51. The device of claim 26, wherein the device is capable of attaining a 90% time response to a 100 mg/dL glucose concentration step in less than 5 minutes.

52. The device of claim 26, wherein the device is configured to reduce or eliminate motion artifact.

53. A device for measuring a glucose concentration in a host, the device comprising:

an electrode surface operably connected to an electronic circuit and configured to continuously measure in vivo a signal associated with a glucose concentration in a host; and

a membrane located over at least a portion of the electrode surface, wherein the membrane is configured to control a flux of oxygen and glucose;

wherein at least 95% of glucose concentration values measured by the device are within 25% of corresponding values determined by analysis of blood over a time period of at least 2 days.

54. The device of claim 53, wherein the time period is at least 3 days.

55. The device of claim 53, wherein the time period is at least 4 days.

56. The device of claim 53, wherein the time period is at least 5 days.

57. The device of claim 53, wherein the time period is at least 6 days.

58. The device of claim 53, wherein the time period is at least 7 days.

59. The device of claim 53, wherein the time period is at least 10 days.

60. The device of claim 53, wherein the membrane comprises a urethane polymer or polyurethane.

61. The device of claim 60, wherein the urethane polymer or polyurethane comprises a polycarbonate-polyurethane backbone.

62. The device of claim 53, wherein the membrane comprises a cross-linked polymer.

63. The device of claim 53, wherein the device is capable of obtaining a calibration stability that is maintained within 10% for one week.

64. The device of claim 53, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to at least 400 mg/dL.

65. The device of claim 53, wherein the device is capable of attaining a 90% time response to a 100 mg/dL glucose concentration step in less than 5 minutes.

66. The device of claim 53, wherein the device is configured to reduce or eliminate motion artifact.