Method and apparatus for spray processing of porous medical devices

• US 20070036905A1
• Filed: 10/17/2006
• Published: 02/15/2007
• Est. Priority Date: 06/12/2001
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Kramer, Pamela
• Granted Patent: US 7,514,122 B2
• Time in Patent Office: Days
• US Class Current: 427/421.100
• CPC Class Codes: A61L 2300/416 Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus
• CPC Class Codes: A61L 2300/42 Anti-thrombotic agents, anticoagulants, anti-platelet agents
• CPC Class Codes: A61L 2300/606 Coatings
• CPC Class Codes: A61L 2420/02 Methods for coating medical devices
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/106 Inorganic materials other than carbon
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/082 Inorganic materials
• CPC Class Codes: A61L 31/088 Other specific inorganic materials not covered by A61L31/084 or A61L31/086
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• 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: B05B 7/0006 Spraying by means of explosions
• CPC Class Codes: B05B 7/203 the material to be sprayed having originally the shape of a wire, rod or the like
• CPC Class Codes: B05B 7/205 the material to be sprayed being originally a particulate material
• CPC Class Codes: B05B 7/224 the material having originally the shape of a wire, rod or the like
• CPC Class Codes: B05B 7/226 : the material being originally a particulate material
• CPC Class Codes: C23C 24/04 : Impact or kinetic deposition of particles
• CPC Class Codes: C23C 28/00 : Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/028 : Including graded layers in composition or in physical properties, e.g. density, porosity, grain size
• CPC Class Codes: C23C 28/321 : with at least one metal alloy layer
• CPC Class Codes: C23C 28/322 : only coatings of metal elements only
• CPC Class Codes: C23C 28/34 : including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
• CPC Class Codes: C23C 28/3455 : with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• CPC Class Codes: C23C 28/36 : including layers graded in composition or physical properties
• CPC Class Codes: C23C 4/12 : characterised by the method of spraying
• CPC Class Codes: Y10T 428/12021 : having composition or density gradient or differential porosity
• CPC Class Codes: Y10T 428/12292 : Workpiece with longitudinal passageway or stopweld material [e.g., for tubular stock, etc.]
• CPC Class Codes: Y10T 428/12299 : Workpiece mimicking finished stock having nonrectangular or noncircular cross section
• CPC Class Codes: Y10T 428/13 : Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1376 : Foam or porous material containing
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article

Abstract

Thermal spray processing and cold spray processing are utilized to manufacture porous starting materials (such as tube stock, wire and substrate sheets) from biocompatible metals, metal alloys, ceramics and polymers that may be further processed into porous medical devices, such as stents. The spray processes are also used to form porous coatings on consolidated biocompatible medical devices. The porous substrates and coatings may be used as a reservoir to hold a drug or therapeutic agent for elution in the body. The spray-formed porous substrates and coatings may be functionally graded to allow direct control of drug elution without an additional polymer topcoat. The spray processes are also used to apply the drug or agent to the porous substrate or coating when drug or agent is robust enough to withstand the temperatures and velocities of the spray process with minimal degradation.

Claims

1. A method of manufacturing a medical device, comprising:

providing a biocompatible material;

using a spray process to form a porous substrate from the biocompatible material; and

processing the porous substrate into a medical device.

2. The method of claim 1, further comprising applying a therapeutic agent to the porous substrate.

3. The method of claim 2, wherein applying the therapeutic agent to the porous substrate includes selecting the therapeutic agent from the group consisting of antiplatelets, anticoagulants, antifibrins, antiinflammatories, antithrombins, and antiproliferatives.

4. The method of claim 2, wherein applying the therapeutic agent to the porous substrate includes impregnating the porous substrate with paclitaxel.

5. The method of claim 1, wherein providing the biocompatible material includes providing a metal alloy selected from the group consisting of iron-based, cobalt-based and titanium-based alloys.

6. The method of claim 1, wherein processing the porous substrate includes forming a stent.

7. The method of claim 6, further comprising applying a polymer layer on an outer surface of the stent.

8. The method of claim 6, further comprising using a spray process to form a porous layer of the biocompatible materials on an outer surface of the stent.

9. A method of manufacturing a drug eluting stent, comprising:

providing a biocompatible material;

forming a porous substrate from the biocompatible material, wherein a spray process is used;

processing the porous substrate into a porous tube stock;

forming a pattern in the porous tube stock to form a porous stent; and

impregnating the porous stent with a therapeutic agent.

10. The method of claim 9, further comprising applying a therapeutic agent to the porous substrate.

11. The method of claim 10, wherein applying the therapeutic agent to the porous substrate includes selecting the therapeutic agent from the group consisting of antiplatelets, anticoagulants, antifibrins, antiinflammatories, antithrombins, and antiproliferatives.

12. The method of claim 10, wherein applying the therapeutic agent to the porous substrate includes impregnating the porous substrate with paclitaxel.

13. The method of claim 9, wherein providing the biocompatible material includes providing a metal alloy selected from the group consisting of iron-based, cobalt-based and titanium-based alloys.

14. The method of claim 9, further comprising applying a polymer layer on an outer surface of the stent.

15. The method of claim 9, further comprising using a spray process to form a porous layer of the biocompatible materials on an outer surface of the stent.

16. A system for manufacturing a drug eluting stent, comprising:

means for providing a biocompatible material;

means for spray processing the biocompatible material to form a porous substrate;

means for processing the porous substrate into a porous tube stock;

means for forming a porous stent from the porous tube stock; and

means for applying a drug to the porous stent.

17. A method of coating a medical device, comprising:

providing a medical device;

providing a coating material;

applying the coating material to the medical device by cold spray thermal processing wherein powder particles are introduced into a high pressure gas where both the gas and particles enter a supersonic jet which is directed against the medical device forming a porous coating, and wherein the medical device is selected from the group consisting of a stent, guide wires, lead tips, catheters, and markers;

wherein the porous coating is functionally graded,

wherein the thickness of the coating on the medical device is varied, and

applying a drug to the porous coating on the medical device.

18. The method of claim 17, wherein applying the drug to the porous coating includes selecting the drug from the group consisting of antiplatelets, anticoagulants, antifibrins, antiinflammatories, antithrombins, and antiproliferatives.

19. The method of claim 17, wherein providing the coating material includes providing a metal alloy selected from the group consisting of iron-based, cobalt-based and titanium-based alloys.

21. The method of claim 17, wherein providing the medical device includes forming a stent.