Polymer and metal composite implantable medical devices

• US 8,172,897 B2
• Filed: 06/28/2004
• Issued: 05/08/2012
• Est. Priority Date: 04/15/1997
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Gale, David C., Huang, Bin, Yan, John Y., Dehnad, Houdin, Capek, John M
• Primary Examiner(s): McDermott, Corrine M
• Assistant Examiner(s): Ou, Jing Rui
• Application Number:
  US10/880,025
• Publication Number:
  US 20050209680A1
• Time in Patent Office: 2,871 Days
• Field of Search: 623/1.15, 623/1.12, 623/1.13, 623/1.14, 623/1.38, 623/1.4, 623/1.42, 623/1.44, 623/1.45, 623/1.46, 427/2.1
• US Class Current: 623/1.38
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• 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 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2002/91583 by a bridge, whereby at least one of its ends is connected along the length of a strut between two consecutive apices within a band
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2250/003 differing in adsorbability or resorbability, i.e. in adsorption or resorption time
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• 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 2300/45 Mixtures of two or more drugs, e.g. synergistic mixtures
• CPC Class Codes: A61L 2300/604 Biodegradation
• CPC Class Codes: A61L 2300/606 Coatings
• CPC Class Codes: A61L 2400/12 Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/028 Other inorganic materials not covered by A61L31/022 - A61L31/026
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/146 : Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/148 : Materials at least partially resorbable by the body
• CPC Class Codes: A61L 31/16 : Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: Y10T 29/49982 : Coating

Abstract

A device and a method of manufacturing an implantable medical device, such as a stent, are described herein. The device includes a metallic region composed of a bioerodable metal and a polymer region composed of a biodegradable polymer contacting the metallic region. The metallic region may erode at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In certain embodiments, the polymer region is an outer layer and the metallic region is an inner layer of the device. A further aspect of the invention includes device and a method of manufacturing the device that includes a mixture of a biodegradable polymer and bioerodable metallic particles. The mixture may be used to fabricate an implantable medical device or to coat an implantable medical device. In some embodiments, the metallic particles are metallic nanoparticles.

Claims

1. A stent for implanting in a vascular lumen, comprising a stent body that is expandable from a pre-implant configuration to a post-implant configuration inside the vascular lumen, the stent body including a strut having a cross-section, wherein the cross-section of the strut including:

a metallic region comprising a bioerodable metal;

wherein the bioerodable metal comprises a pure or substantially pure bioerodable metal; and

a polymer region comprising a biodegradable polymer contacting and disposed over the metallic region, wherein the metallic region erodes at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids, and wherein the metallic region starts to erode when the polymer region is at least partially degraded after the stent body has been expanded to the post-implant configuration inside the vascular lumen, wherein the bioerodable metal erodes at a faster rate when exposed to bodily fluids than the biodegradable polymer when exposed to bodily fluids, wherein the metallic region is configured to completely or almost completely erode before the polymer region is completely or almost completely eroded.

2. The stent of claim 1, wherein the polymer comprises at least one material selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide.

3. The stent of claim 1, wherein the bioerodable metal is selected from the group consisting of magnesium, zinc, and iron.

4. The stent of claim 1, wherein the biodegradable polymer comprises a pure or substantially pure biodegradable polymer.

5. The stent of claim 1, wherein the biodegradable polymer comprises a mixture of at least two types of biodegradable polymers.

6. The stent of claim 1, wherein the biodegradable polymer comprises a bulk eroding polymer.

7. The stent of claim 1, wherein the biodegradable polymer comprises a surface eroding polymer.

8. The stent of claim 1, wherein the bioerodable metal comprises a mixture comprising at least two types of metals.

9. The stent of claim 1, wherein the bioerodable metal comprises an alloy comprising at least two types of metals.

10. The stent of claim 1, wherein the polymer region comprises an active agent.

11. The stent of claim 1, wherein the metallic region comprises pores comprising an active agent.

12. The stent of claim 1, wherein the polymer region is configured to release an active agent.

13. The stent of claim 1, wherein the polymer region is configured to delay, inhibit, or prevent erosion of the metallic region.

14. The stent of claim 1, wherein the polymer region is configured to inhibit or prevent erosion of the metallic region in a manner that allows the metallic region to provide mechanical support to a bodily lumen.

15. The stent of claim 1, wherein the polymer region is configured to inhibit or prevent erosion of the metallic region for at least a portion of, all of, or longer than the time period that the metallic region is desired to provide mechanical support of a bodily lumen.

16. The stent of claim 1, wherein the stent comprises sufficient radio-opacity to be imaged by X-Ray radiation.

17. The stent of claim 1, wherein the metallic region comprises a cylindrical or substantially cylindrical coil or mesh of metallic wire.

18. The stent of claim 1, wherein the metallic region comprises a cylindrical pattern of struts.

19. The stent of claim 1, wherein the polymer region comprises a coating comprising the biodegradable polymer on the metallic region.

20. The stent of claim 1, wherein the polymer region comprises uniform or substantially uniform erosion rate.

21. The stent of claim 1, wherein the metallic region comprises a uniform or substantially uniform composition and uniform or substantially uniform erosion rate.

22. The stent of claim 1, wherein the polymer region comprises at least two layers, wherein at least two layers comprise different erosion rates.

23. The stent of claim 1, wherein the metallic region comprises at least two layers, wherein at least two layers comprise different erosion rates.

24. The stent of claim 1, further comprising a second metallic region contacting the polymer region, wherein the polymer region is between the metallic region and the second metallic region.

25. The stent of claim 1, wherein the polymer region inhibits or prevents direct contact or exposure of the metallic region to a vascular environment.

26. The stent of claim 1, wherein the polymer region completely covers inward-facing surfaces and outward-facing surfaces of the stent.

27. The stent of claim 1, wherein the bioerodable metal is magnesium.