Electrically conductive lead and a method of producing such a lead

• US 20040172117A1
• Filed: 04/19/2004
• Published: 09/02/2004
• Est. Priority Date: 03/29/2001
• Status: Active Grant

• Current Assignee: St. Jude Medical AB (Abbott Laboratories)
• Original Assignee: St. Jude Medical AB (Abbott Laboratories)
• Inventors: Hill, Rolf, Obel, Martin, Wargelius, Maria, Kalling, Sven
• Granted Patent: US 7,398,126 B2
• Time in Patent Office: Days
• US Class Current: 607/120
• CPC Class Codes: A61N 1/0568 with drug delivery

Abstract

In an electrically conductive lead adapted for implantation in a human or animal body, and a method for making such a lead, a drug-dispensing member is disposed at a distal end portion of the lead, at which an electrode member is disposed that is adapted to emit and/or sense electrical signals associated with medical therapy. The drug-dispensing member has a configuration so that, after implantation, the amount of drug released into the body per time unit is automatically controlled to smoothly vary with time from al larger amount to a smaller amount in accordance with a predetermined relationship of the amount of drug released as a function of time.

Claims

1. An electrically conductive lead suitable to be implanted in a human or animal body, the lead comprising:

a proximal end portion designed to be attached to a device,

a distal end portion comprising at least one electrode member (12) for emitting and/or sensing electrical signals,

an elongated body extending between said proximal end portion and said distal end portion,

a drug dispensing member (26) positioned at said distal end portion and comprising a drug adapted to be released into said human or animal body, wherein the drug dispensing member (26) is located such that a part of the surface of the drug dispensing member faces the exterior of the lead, and wherein said drug dispensing member (26) is designed such that, once the lead has been implanted into said body, the amount of drug released into the body per time unit is automatically controlled to smoothly vary with time from a larger amount to a smaller amount in accordance with a predetermined relationship of the amount of drug released as a function of time.

2. An electrically conductive lead according to claim 1, wherein said drug comprises an anti-inflammatory agent.

3. An electrically conductive lead according to claim 1 or 2, wherein the design of the drug dispensing member (26) is such that the decrease in the amount of drug released into the body from a maximum amount released during the first hours after implantation to an amount which is about ⅓

of this maximum amount takes at least 24 hours.

4. An electrically conductive lead according to any of the preceding claims, wherein said distal end portion comprises at least one cavity (28) having an opening (30) arranged at an exterior surface of the distal end portion of the lead such that the cavity (28) is open to the exterior of the distal end portion, wherein said drug dispensing member (26) is located in said cavity (28), and wherein the shape of the cavity (28) is such that the amount of drug released into the body per time unit is controlled by said shape.

5. An electrically conductive lead according to claim 4, wherein the shape of said cavity (28) is such that the cross-sectional area of the cavity varies smoothly from a maximum area (32) at said opening (30) at the exterior surface of the distal end portion to an essentially smaller area (34) at a position further into said cavity (28).

6. An electrically conductive lead according to claim 5, wherein the shape of said cavity (28) is such that said maximum cross-sectional area (32) at said opening (30) at the exterior surface of the distal end portion is at least twice the smallest cross-sectional area (34) of said cavity (28).

7. An electrically conductive lead according to any of claims 4-6, wherein said at least one electrode member (12) comprises a first surface portion (16) facing the exterior of the distal end portion of the lead and a second surface portion (18) facing the interior of the lead, wherein said cavity (28) is located such that said opening (30) is located in said first surface portion (16).

8. An electrically conductive lead according to claim 7, wherein said cavity (28) is located such that the cavity (28) does not extend to the second surface portion (18), such that it does not extend all the way through the electrode member (12), wherein the cavity (28) does not have any opening towards the interior of the lead.

9. An electrically conductive lead according to claim 7 or 8, wherein said cavity (28) extends from said first surface portion (16) and has a minimum cross-sectional area (34) at an intermediate position of said cavity (28) which is smaller than the cross-sectional area (36) of the cavity (28) at a position located proximal of said intermediate position.

10. An electrically conductive lead according to any of claims 4-9, wherein said cavity (28) is positioned such that said opening (30) is located at the distal end tip of the lead and such that the cavity (28) extends in the longitudinal direction of the lead.

11. An electrically conductive lead according to any of claims 4-10, wherein said distal end portion comprises a plurality of said cavities (28).

12. An electrically conductive lead according to any of claims 4-11, wherein said drug dispensing member or members (26) are formed in a material that is soluble or resorbable in body fluids.

13. An electrically conductive lead according to any of claims 1-3, wherein said electrode member (12) forms the distal end portion of the lead and wherein said drug dispensing member (26) is positioned on the surface of said electrode member.

14. An electrically conductive lead according to claim 13, wherein said drug dispensing member (26) is formed in a material that is soluble or resorbable in body fluids, and wherein the drug dispensing member (26) has a shape that is such that the exterior surface area of the drug dispensing member (26) will decrease with time, when the drug dispensing member (26) is dissolved or resorbed, in such a manner that said controlled release of the drug is achieved.

15. An electrically conductive lead according to claim 14, wherein said drug dispensing member (26) has a cone-like shape with a base surface (38) attached to said electrode member (12) and a narrow end (40), pointing away from said electrode member (12).

16. An electrically conductive lead according to any of the claims 1-15, wherein said drug dispensing member (26) comprises different concentration of said drug in different parts of the drug dispensing member (26) such that the amount of drug released over time is controlled at least in part by the varying concentration of the drug in said member (26).

17. An electrically conductive lead according to any of the claims 1-16, wherein different parts of the drug dispensing member (26) comprise materials of different compositions, which are soluble or resorbable in body fluids with different pace, wherein said different parts are positioned such that the amount of drug released over time is controlled at least in part by the different compositions and the position of the different parts in said drug dispensing member (26).

18. A method of producing a an electrically conductive lead suitable to be implanted in a human or animal body and comprising a drug to be released into said body with a predetermined amount as a function of time after implantation, the method comprising:

providing an electrically conductive lead having a proximal end portion designed to be attached to a device, a distal end portion, which comprises at least one electrode member (12) for emitting and/or sensing electrical signals, and an elongated body extending between said proximal end portion and said distal end portion,

providing a drug dispensing member (26) at said distal end portion, which drug dispensing member (26) comprises said drug adapted to be released into said human or animal body, wherein the drug dispensing member (26) is arranged such that a part of the surface of the drug dispensing member (26) faces the exterior of the lead, and wherein said drug dispensing member (26) is designed such that, once the lead has been implanted into said body, the amount of drug released into the body per time unit is automatically controlled to smoothly vary with time from a larger amount to a smaller amount in accordance with a predetermined relationship of the amount of drug released as a function of time.

19. A method according to claim 18, wherein said drug comprises an anti-inflammatory agent.

20. A method according to any of claims 18 and 19, wherein said relationship is determined such that the decrease in the amount of drug released into the body from a maximum amount released during the first hours after implantation to an amount which is about ⅓

of this maximum amount takes at least 24 hours.

21. A method according to any of the claims 18-20, comprising the step of forming said distal end portion such that it comprises at least one cavity (28) having an opening (30) arranged at an exterior surface of the distal end portion of the lead such that the cavity (28) is open to the exterior of the distal end portion, and positioning said drug dispensing member (26) in said cavity (28), wherein the shape of the cavity (28) is designed such that the amount of drug released into the body per time unit is controlled by said shape.

22. A method according to claim 21, comprising the step of forming said cavity (28) such that the shape of said cavity (28) is such that the cross-sectional area of the cavity (28) varies smoothly from a maximum area (32) at said opening (30) at the exterior surface of the distal end portion to an essentially smaller area (34) at a position further into said cavity (28).

23. A method according to claim 22, wherein the shape of said cavity (28) is formed such that said maximum cross-sectional area (32) at said opening (30) at the exterior surface of the distal end portion is at least twice the smallest cross-sectional area (34) of said cavity (28).

24. A method according to any of claims 21-23, wherein said at least one electrode member (12) is formed such that it comprises a first surface portion (16) facing the exterior of the distal end portion of the lead and a second surface portion (18) facing the interior of the lead, wherein said cavity (28) is located such that said opening (30) is located in said first surface portion (16).

25. A method according to claim 24, wherein said cavity (28) is formed such that the cavity (28) does not extend to the second surface portion (18), such that it does not extend all the way through the electrode member (12), wherein the cavity (28) does not have any opening towards the interior of the lead.

26. A method according to claim 24 or 25, wherein said cavity (28) is formed such that it extends from said first surface portion and has a minimum cross-sectional area (34) at an intermediate position of said cavity which is smaller than the cross-sectional area (36) of the cavity (28) at a position located proximal of said intermediate position.

27. A method according to any of claims 21-26, wherein said cavity (28) is formed such that said opening (30) is located at the distal end tip of the lead and such that the cavity (28) extends in the longitudinal direction of the lead.

28. A method according to any of claims 21-27, wherein said distal end portion is formed to comprise a plurality of said cavities (28).

29. A method according to any of claims 21-28, wherein said drug dispensing member or members (26) are formed in a material that is soluble or resorbable in body fluids.

30. A method according to any of claims 18-20, wherein said electrode member (12) is formed to constitute the distal end portion of the lead and wherein said drug dispensing member (26) is positioned on the surface of said electrode member (12).

31. A method according to claim 30, wherein said drug dispensing member (26) is formed in a material that is soluble or resorbable in body fluids, and wherein the drug dispensing member (26) is formed to have a shape that is such that the exterior surface area of the drug dispensing member (26) will decrease with time, when the drug dispensing member (26) is dissolved or resorbed, in such a manner that said controlled release of the drug is achieved.

32. A method according to claim 31, wherein said drug dispensing member (26) is formed to have a cone-like shape, with a base surface (38) attached to said electrode member (12) and a narrow end (40), pointing away from said electrode member (12).

33. A method according to any of the claims 18-32, wherein said drug, dispensing member (26) is formed such that it comprises different concentration of said drug in different parts of the drug dispensing member (26) such that the amount of drug released over time is controlled at least in part by the varying concentration of the drug in said member (26).

34. A method according to any of the claims 18-33, wherein said drug dispensing member (26) is formed such that different parts of the drug dispensing member (26) comprise materials of different compositions, which are soluble or resorbable in body fluids with different pace, wherein said different parts are positioned such that the amount of drug released over time is controlled at least in part by the different compositions and the position of the different parts in said drug dispensing member (26).