Porous stent drug delivery system

• US 5,972,027 A
• Filed: 09/30/1997
• Issued: 10/26/1999
• Est. Priority Date: 09/30/1997
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Johnson, Michael W.
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): Nguyen, Tram A.
• Application Number:
  US08/940,696
• Time in Patent Office: 756 Days
• Field of Search: 623/1, 623/11, 623/12, 623/16, 606/108, 606/191, 606/194, 606/195, 606/198, 424/422, 424/423
• US Class Current: 623/1.42
• 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 made of a powdered metal or polymer are provided as well their method of manufacture. These stents are 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 materials in a die cavity to a pressure treatment followed by a heat treatment. The material 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 or polymer stent is then loaded with one or more drugs.

Claims

1. 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, at least a portion of the main body portion formed of at least one material having pores therein, the material having been formed from at least one powdered metal, the stent comprising at least two separate regions arranged along the length of the stent, the first region formed of a first material having first pores within, the first material characterized by a first porosity and a first mean pore size, the first material having been formed from a first powdered metal, the second region formed of a second material having second pores within, the second material characterized by a second porosity and a second mean pore size, the second material having been formed from a second powdered metal.

2. The stent of claim 1 wherein at least one of the first and second regions has a porosity of twenty to eighty percent by volume.

3. The stent of claim 2 wherein at least one of the first and second regions has a porosity of between forty and sixty percent of the total volume of the metal.

4. The stent of claim 1 formed of a plurality of strands of a metal, the metal having pores therein.

5. The stent of claim 1 wherein the stent is coated with one or more layers of one or more drug containing materials.

6. The stent of claim 1 wherein the first or second powdered metal is stainless steel.

7. The stent of claim 6 wherein the pores in the first and second materials contain at least one drug.

8. The stent of claim 7 wherein the 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.

9. The stent of claim 1 wherein the first pores contain a first drug and the second pores contain a second drug.