Stent Drug Delivery System

• US 20080288059A1
• Filed: 07/11/2008
• Published: 11/20/2008
• Est. Priority Date: 09/30/1997
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Johnson, Michael W.
• Granted Patent: US 7,963,990 B2
• Time in Patent Office: Days
• US Class Current: 623/1.43
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 2300/00 Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
• CPC Class Codes: A61L 2300/608 having two or more layers
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/14 Titanium or alloys thereof
• CPC Class Codes: B23K 2103/26 Alloys of Nickel and Cobalt and Chromium
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10T 29/49995 : Shaping one-piece blank by removing material

Abstract

Expandable intraluminal stents are provided as well their method of manufacture. These stents are made of metal, the metal characterized by a desired porosity, with a drug compressed into the pores of the stent. The stents are formed by subjecting one or more powdered metals in a die cavity to a pressure treatment followed by a heat treatment. The metal may be cast directly in a stent-like form or cast into sheets or tubes from which the inventive stents are produced. The so-formed porous metal stent is then loaded with one or more drugs.

Claims

1-22. -22. (canceled)

23. An expandable intraluminal stent comprising:

a main body portion having a first end, a second end and a flow passage defined therethrough, the main body portion being sized for intraluminal placement within a body passage and subsequent expansion for implantation, the stent further comprising at least two separate regions arranged along the length of the main body portion, the first region comprising a first powdered material having first pores within, the first material characterized by a first porosity and a first pore size, the second region comprising a second powdered material having second pores within, the second material characterized by a second porosity and a second pore size.

24. The stent of claim 23, wherein the first powdered material and the second powdered material are characterized by different average particle size.

25. The stent of claim 23, wherein the first powered material comprises a first polymer, and wherein the second powdered material comprises a second polymer.

26. The stent of claim 25, wherein the first powdered material comprises the first polymer and a first metal, and wherein the second powdered material comprises the second polymer and a second metal.

27. The stent of claim 26, wherein the first metal and the second metal are characterized by different average particle size.

28. The stent of claim 26, wherein at least one of the first and second regions has a porosity of twenty percent to eighty percent by volume.

29. The stent of claim 26, wherein at least one of the first and second regions has a porosity of between forty percent and sixty percent by volume.

30. The stent of claim 26, wherein the first metal is different than the second metal.

31. The stent of claim 26, wherein the first polymer is different than the second polymer.

32. The stent of claim 26, wherein the pores in the first material and the second material contain at least one drug.

33. The stent of claim 32, wherein the first pores contain a first drug and the second pores contain a second drug, the first drug being different from the second drug.

34. The stent of claim 32, wherein the stent is coated with one or more layers of one or more drug containing materials.

35. The stent of claim 32, wherein the at least one drug is selected from the group consisting of smooth muscle cell inhibitors, collagen inhibitors, vasodilators, anti-platelet substances, anti-thrombotic substances, anti-coagulants, cholesterol reducing agents, angiogenics and combinations thereof.

36. A method of forming a stent comprising the steps of:

providing a first powdered polymer;

providing a second powdered polymer, the first powdered polymer and second powdered polymer having different compositions or different physical properties or both;

treating the first and second powdered polymer to form a stent preform having a length, the stent preform including a first region comprising the first powdered polymer and a second region comprising the second powdered polymer, the first region displaced along the length of the stent preform from the second region; and

forming a stent from the stent preform.

37. The method of claim 36, wherein the step of providing a first powdered polymer further includes providing a first powdered metal, and wherein the step of providing a second powdered polymer further includes providing a second powdered metal, the first powdered metal and second powdered metal having different compositions or different physical properties or both.

38. The method of claim 37, wherein the treating step includes subjecting the first powdered metal, the first powdered polymer, the second powdered metal, and the second powdered polymer to high pressure to form the stent preform.

39. The method of claim 37, wherein the treating step includes subjecting the first powdered metal, the first powdered polymer, the second powdered metal, and the second powdered polymer to high pressure to form a compact, and sintering the compact to form the stent preform.

40. The method of claim 37, wherein the treating step includes sintering the first powdered metal, the first powdered polymer, the second powdered metal, and the second powdered polymer to form the stent preform.

41. The method of claim 37, wherein the first powdered polymer and the second powdered polymer are characterized by different average particle size.

42. The method of claim 37, wherein the first powdered metal and the second powdered metal are characterized by different average particle size.

43. The method of claim 37, wherein the first powdered metal and the second powdered metal are of different compositions

44. The method of claim 37, wherein the first powdered polymer and the second powdered polymer are of different compositions.

45. The method of claim 37, further comprising the step of filling the pores in the first material and the second material with at least one drug.

46. The method of claim 45, wherein the step of filling the pores in the first material and the second material with at least one drug further comprises filling the pores in the first material with a first drug and filling the pores in the second material with a second drug, the first drug being different from the second drug.

47. The method of claim 45, further comprising the step of coating the stent with one or more layers of one or more drug containing materials