Method of forming a drug-eluting medical device

• US 8,616,040 B2
• Filed: 09/17/2010
• Issued: 12/31/2013
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Inventors: Bienvenu, Ryan
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US12/884,272
• Publication Number:
  US 20120067103A1
• Time in Patent Office: 1,201 Days
• Field of Search: 72/76, 722/74, 723/421, 723/671, 723/68, 723/700.1, 727/00, 72/38, 724/668, 623/1.15, 623/1.42, 216/56, 216/72, 216/73, 216/100, 216/109, 438/706, 294/12, 294/13
• US Class Current: 72/367.1
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• 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 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61L 2400/18 Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: A61M 2207/10 Device therefor
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: B23P 19/04 for assembling or disassembling parts
• CPC Class Codes: C23F 1/12 Gaseous compositions
• CPC Class Codes: Y10T 29/4987 Elastic joining of parts

Abstract

A method of forming a stent includes the steps of forming a composite member into a stent pattern, forming openings through an outer member of the composite member, processing the composite member to remove a portion of the composite member without adversely affecting the outer member, and swaging the outer member to create a plurality of lumens. The composite member may be formed of an outer member with an hourglass-shaped inner member, wherein the processing step removes the inner member and the swaging step forms two lumens from the hourglass shaped cavity. The composite member may be formed of an outer member, an inner member, and an intermediate member, wherein the processing step removes the intermediate member and the swaging step presses portions of the outer member into contact with the inner member to form two lumens separated by the inner member.

Claims

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

utilizing a composite member including an outer member and an hourglass shaped core member disposed within a lumen of the outer member;

shaping the composite member into a stent pattern;

forming openings through the outer member;

after the step of shaping the composite member into the pattern, processing the composite member such that the core member is removed from the outer member without adversely affecting the outer member, thereby leaving an outer member with an hourglass shaped lumen; and

swaging the outer member such that the hourglass shaped lumen is separated into a first lumen and a second lumen separated by a portion of the outer member.

2. The method of claim 1, further comprising the step of filling the first lumen with a first biologically or pharmacologically active substance and filling the second lumen with a second biologically or pharmacologically active substance after the core member has been removed.

3. The method of claim 2, wherein the first and second biologically or pharmacologically active substances are the same.

4. The method of claim 2, wherein the first and second biologically or pharmacologically active substances are different.

5. The method of claim 2, wherein the first and second biologically or pharmacologically active substances are selected from the group consisting of antineoplastic, antimitotic, antiinflammatory, antiplatelet, anticoagulant, anti fibrin, antithrombin, antiproliferative, antibiotic, antioxidant, and antiallergic substances as well as combinations thereof.

6. The method of claim 1, wherein the step of processing the composite member comprises exposing the composite member to an etchant that reacts with the core member to remove the core member, wherein the etchant does not react with the outer member.

7. The method of claim 6, wherein the etchant is a liquid chemical that dissolves the core member.

8. The method of claim 6, wherein the etchant is a gas.

9. The method of claim 8, wherein the outer member is formed from MP35N, the core member is formed from one of tantalum, tungsten, molybdenum, niobium, rhenium, carbon, germanium, and silicon, and the etchant is xenon difluoride.

10. The method of claim 6, wherein the core member is soluble in the etchant and the outer member is not soluble in the etchant.

11. The method of claim 1, wherein the step of processing the composite member comprises heating the composite member to a temperature to sublimate the core member.

12. The method of claim 1, wherein the step of processing the composite member comprises heating the composite member to a temperature to melt the core member.

13. The method of claim 1, wherein the composite member comprises a core wire, and wherein the step of shaping the composite member into the stent pattern comprises bending the core wire into a waveform and helically wrapping the waveform into a tubular configuration.

14. The method of claim 1, wherein the step of swaging the outer member is performed prior to the step of processing the composite member such that the core member is removed from the outer member.

15. The method of claim 1, wherein the step of swaging the outer member is performed after the step of processing the composite member such that the core member is removed from the outer member.