Spray processing of porous medical devices

• US 7,163,715 B1
• Filed: 12/30/2002
• Issued: 01/16/2007
• Est. Priority Date: 06/12/2001
• Status: Expired due to Fees

• Current Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Kramer, Pamela A.
• Primary Examiner(s): MIGGINS, MICHAEL C
• Application Number:
  US10/331,838
• Time in Patent Office: 1,478 Days
• Field of Search: 428/35.7, 428/544, 428/35.8, 428/36.5, 427/96.2, 427/108, 427/110, 427/189, 427/191, 427/202, 427/205, 427/427, 514/182, 604/891.1, 623/1.15, 623/1.42
• US Class Current: 427/189
• 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 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; and

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

2. The method of claim 1, wherein applying the drug to the porous coating includes impregnating the porous coating with paclitaxel.

3. The method of claim 1, wherein applying the drug to the porous coating includes using a cold spray process.

4. The method of claim 1, wherein the coating material is sprayed on the device as solid particles.

5. The method of claim 1, wherein applying the drug to the porous coating includes selecting the drug from the group consisting of antiplatelets, anticoagulants, antifibrins, antiinflammatories, antithrombins, and antiproliferatives.

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

7. The method of claim 6, wherein providing the medical device includes forming a stent.

8. The method of claim 7, wherein providing the medical device includes forming the stent from stainless steel.

9. The method of claim 8, wherein providing the coating material includes using stainless steel.

10. The method of claim 7, wherein providing the medical device includes forming the stent from a cobalt-chromium alloy.

11. The method of claim 10, wherein providing the coating material includes using a cobalt-chromium alloy.

12. The method of claim 5, wherein providing the coating material includes providing a metal selected from the group consisting of iron, titanium, tungsten, tantalum, vanadium, gold, silver, palladium, platinum and iridium.

13. The method of claim 1, further comprising applying a polymer to the porous coating.

14. The method of claim 13, wherein applying the polymer to the porous coating includes using a spray process.

15. 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;

applying a drug to the porous coating on the medical device; and

wherein the porous coating is functionally graded with different degrees of porosity and/or density that allows the coating to function as a diffusion barrier to control the release of the drug.

16. The method of claim 15, wherein the coating material is sprayed on the device as molten material.