Bioerodible endoprosthesis with biostable inorganic layers

• US 8,128,689 B2
• Filed: 09/14/2007
• Issued: 03/06/2012
• Est. Priority Date: 09/15/2006
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Weber, Jan, Atanasoska, Liliana, Schewe, Scott
• Primary Examiner(s): Stewart, Alvin J.
• Application Number:
  US11/855,542
• Publication Number:
  US 20080071352A1
• Time in Patent Office: 1,635 Days
• Field of Search: 623 138- 154, 623/1.15, 623/1.13, 623/23.7, 623/23.71, 623/23.72, 623/23.73, 623/23.74, 623/23.75, 623/23.76
• US Class Current: 623/1.42
• 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 31/022 Metals or alloys
• CPC Class Codes: A61L 31/082 Inorganic materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence

Abstract

Medical devices such as endoprostheses (e.g., stents) containing one or more biostable layers (e.g., biostable inorganic layers) and a biodegradable underlying structure are disclosed.

Claims

1. A stent comprising a biostable layer and a bioerodible underlying structure, wherein the biostable layer is about 5% or less of a wall thickness of a strut of the stent, wherein the bioerodible underlying structure comprises a bioerodible metal.

2. The stent of claim 1, wherein the biostable layer has a thickness on average of about 10 to 20 nm.

3. The stent of claim 1, wherein the biostable layer has an average volume in the range of about 5,000 to 20,000 cubic micrometer per square millimeter of stent surface area.

4. The stent of any of claims 1-3, wherein the biostable layer comprises ceramic material.

5. The stent of claim 1, wherein the biostable layer comprises one or more metal oxides.

6. The stent of any of claims 1-3, wherein the biostable layer comprises a crystalline form of titanium oxide.

7. The stent of claim 1, wherein the biostable layer is on a surface of the stent.

8. The stent of claim 7, wherein the biostable layer is on an interior surface, an exterior surface or a sidewall.

9. The stent of claim 1, wherein at least a portion of the biostable layer is covered by a bioerodible layer.

10. The stent of claim 1, wherein the biostable layer formed by a sol-gel process.

11. The stent of claim 1, wherein the biostable layer is formed by a process comprising:

modifying a selected portion of the surface of the underlying structure with hydroxyl groups;

allowing the hydroxyl groups to react with one or more metal alkoxides to form a covalently-bound biostable layer of the one or more metal alkoxides;

(optionally) removing excess adsorbed metal alkoxide; and

hydrolyzing the covalently-bound surface of the biostable layer.

12. The stent of claim 1, wherein the biostable layer is a monolayer.

13. The stent of claim 1, comprising one or more monolayers of a metal oxide, an organic material, a polymeric material or a biological material.

14. The stent of claim 1, further comprising at least one therapeutic agent.

15. The stent of claim 14, wherein the therapeutic agent is paclitaxel.

16. A method comprising implanting the stent of claim 1 in a body passageway to stimulate the attachment of endothelial cells to the stent or control the erosion rate of the underlying structure.

17. The method of claim 16, wherein at least a portion of the stent degrades over a period of time inside the organism and releases a therapeutic agent.

18. The method of claim 16, wherein the stent is implanted in a cardiovascular passageway.

21. The stent of claim 1, wherein the bioerodible underlying structure comprises magnesium or an alloy thereof.

19. A stent comprising a biostable layer and a bioerodible underlying structure, wherein the biostable layer is about 5% or less of a wall thickness of a strut of the stent, wherein the bioerodible underlying structure comprises a bioerodible metal, wherein the biostable layer comprises one or more of titanium oxide, ruthenium oxide, or iridium oxide.

20. A stent comprising a biostable layer and a bioerodible underlying structure, wherein the biostable layer is about 5% or less of a wall thickness of a strut of the stent, wherein the biostable layer comprises a plurality of nodules about 15-20 nm in size.