ENDOPROSTHESIS WITH POROUS RESERVOIR AND NON-POLYMER DIFFUSION LAYER

• US 20090118821A1
• Filed: 11/02/2007
• Published: 05/07/2009
• Est. Priority Date: 11/02/2007
• Status: Abandoned Application

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Weber, Jan, Scheuermann, Torsten, Clarke, John T.
• Application Number:
  US11/934,353
• Publication Number:
  US 20090118821A1
• Time in Patent Office: Days
• US Class Current: 623/1.490
• CPC Class Codes: A61L 2300/608 having two or more layers
• CPC Class Codes: A61L 2420/08 Coatings comprising two or more layers
• CPC Class Codes: A61L 31/082 Inorganic 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

Abstract

An endoprosthesis such as a coronary stent includes a porous reservoir of drug, e.g., a porous layer formed of a ceramic and an overlayer formed of ceramic or metal for controlling elution of drug from the reservoir.

Claims

1. An endoprosthesis, comprising:

a surface,

a first porous layer formed of a first ceramic over the surface, and

a second porous layer formed of a second ceramic or a metal over the first layer.

2. The endoprosthesis of claim 1, wherein the first porous layer includes a drug.

3. The endoprosthesis of claim 2, wherein the second layer has less porosity than the first layer.

4. The endoprosthesis of claim 3, wherein the pore size of the second layer is smaller than the pore size of the first layer.

5. The endoprosthesis of claim 1, wherein the thickness of the second layer is about 10 to about 500 nm.

6. The endoprosthesis of claim 1, wherein the thickness of the first layer is about 0.1 to about 3 micron.

7. The endoprosthesis of claim 1, wherein the surface is the surface of a stent body.

8. The endoprosthesis of claim 1, wherein the second layer is formed of metal.

9. The endoprosthesis of claim 1, wherein the first layer and the second layer form a drug delivery system substantially free of polymer.

10. The endoprosthesis of claim 1, wherein the second layer is formed of a second ceramic.

11. The endoprosthesis of claim 10, wherein the second ceramic is IROX.

12. The endoprosthesis of claim 10, wherein the second ceramic has a smooth globular morphology.

13. The endoprosthesis of claim 12, wherein the second ceramic is different from the first ceramic.

14. A method of forming an endoprosthesis, comprising:

forming a first porous layer on the endoprosthesis,

introducing a drug into the first porous layer, and

forming a second porous layer of a ceramic or metal over the drug-containing first layer.

15. The method of claim 14, comprising forming the first porous layer by a sol-gel process.

16. The method of claim 14, comprising forming the first porous layer by a nanocluster deposition process.

17. The method of claim 16, comprising introducing the drug by coating, dipping, spraying in a solvent or applying substantially dry drug particles to the first porous layer.

18. The method of claim 14, comprising introducing the drug by PLD.

19. The method of claim 14, comprising forming the second porous layer by PLD.

20. The method of claim 14, comprising forming pores in the second layer by laser irradiation.

21. The method of claim 14, wherein the second layer is a metal.

22. The method of claim 14, wherein the second layer is ceramic.

23. The method of claim 22, wherein the second layer is IROX.

24. The method of claim 14, comprising introducing the drug during the sol-gel process.

25. The method of claim 14, comprising forming the second porous layer by a nanocluster deposition process.

26. A method of forming an endoprosthesis, comprising

forming a first porous ceramic layer on the endoprosthesis by providing metal oxide sol and treating by heat application at temperatures of about 300°

C. or less; and

forming a second porous layer over the first layer without heating at a temperature of about 300°

C. or more.

27. The method of claim 26, comprising incorporating a drug in the metal oxide sol prior to heat treating.

28. The method of claim 27, comprising the metal oxide is TiOx.

29. A method comprising

providing a stent including a first porous layer formed of a ceramic, the first porous layer incorporating a drug, the stent further including a second porous layer of a different ceramic, and delivering the stent into the body.