Stent coating for eluting medication

• US 8,057,543 B2
• Filed: 01/27/2006
• Issued: 11/15/2011
• Est. Priority Date: 01/28/2005
• Status: Expired due to Fees

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: O'Brien, Robert C., Frysz, Christine A.
• Primary Examiner(s): Sweet; Thomas J
• Assistant Examiner(s): STEWART, JASON-DENNIS NEILKEN
• Application Number:
  US11/307,226
• Publication Number:
  US 20060200231A1
• Time in Patent Office: 2,118 Days
• Field of Search: 623/1.44, 623/1.42, 623/1.11, 427 21- 231
• US Class Current: 623/11.11
• 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 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61L 2300/108 Elemental carbon, e.g. charcoal
• CPC Class Codes: A61L 31/084 Carbon; Graphite
• 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: Y10T 29/49885 with coating before or during assembling

Abstract

A vascular stent comprising a drug-eluting outer layer of a porous sputtered columnar metal having each column capped with a biocompatible carbon-containing material is described. This is done by placing the stent over a close-fitting mandrel and rotating the assembly in a sputter flux. The result is a coating that is evenly distributed over the outward-facing side of the stent'"'"'s wire mesh while preventing the sputtered columnar coating from reaching the inward facing side where a smooth hemocompatible surface is required. The stent is then removed from the mandrel, exposing all surfaces, and finally coated with a layer of carbon such as amorphous carbon or diamond-like carbon. The carbonaceous coating enhances biocompatibility without preventing elutriation of a therapeutic drug provided in the porosity formed between the columnar structures. The result is a stent that is adapted to both the hemodynamic and the immune response requirements of its vascular environment.

Claims

1. A device comprising a biocompatible coating for contact with body tissue, the device comprising:

a) a substrate;

b) an intermediate coating of a metal or a ceramic adhered to the substrate and comprising a plurality of discrete columnar structures, each of the columns having a sidewall extending between a proximal end adhered to the substrate and a distal end spaced therefrom, wherein the sidewalls of immediately adjacent columns do not contact each other to thereby provide an area of the substrate between adjacent columns that is not contacted by the intermediate coating serving as porosity between the columns; and

c) a cap of a carbon-containing material provided on the distal end of each of the plurality of columnar structures.

2. The device of claim 1 wherein the intermediate coating is selected from the group consisting of carbides, oxides, nitrides, oxynitrides, and carbonitrides of titanium, boron, aluminum, calcium, gold, hafnium, iridium, molybdenum, niobium, platinum, rhenium, ruthenium, silicon, silver, tantalum, titanium, tungsten, yttrium, zirconium.

3. The device of claim 1 wherein the carbon-containing material is selected from an amorphous carbon and a diamond-like carbon.

4. The device of claim 1 wherein the intermediate coating is adhered to the substrate and the carbon-containing material is provided as the cap on the distal end of each of the plurality of columnar structures by one of the deposition techniques selected from the group consisting of sputtering, chemical vapor deposition, pulsed laser deposition, reactive evaporation, and as a thermal spray.

5. The device of claim 1 wherein the plurality of columnar structures comprising the intermediate coating each have a length of about 0.1 μ

m to about 20 μ

m.

6. The device of claim 1 wherein the carbon-containing material has a thickness of about 0.05 μ

m to about 2.0 μ

m.

7. A device comprising a biocompatible coating for contact with body tissue, the device comprising:

a) a substrate;

b) an intermediate coating of titanium nitride adhered to the substrate and comprising a plurality of discrete columnar structures, each of the columns having a sidewall extending between a proximal end adhered to the substrate and a distal end spaced therefrom, wherein the sidewails of immediately adjacent titanium nitride columns do not contact each other to thereby provide an area of the substrate between adjacent columns that is not contacted by the intermediate coating serving as porosity adapted for receiving an elutable material between the columns;

c) a cap of a carbon-containing material provided on the distal end of each of the plurality of columnar structures.

8. The device of claim 7 wherein the carbon-containing material is selected from an amorphous carbon and a diamond-like carbon.

9. The device of claim 7 wherein the intermediate coating is adhered to the substrate and the carbon-containing material is provided as the cap on the distal end of each of the plurality of columnar structures by one of the deposition techniques selected from the group consisting of sputtering, chemical vapor deposition, pulsed laser deposition, reactive evaporation, and as a thermal spray.

10. The device of claim 7 wherein the plurality of columnar structures comprising the intermediate coating each have a length of about 0.1 μ

m to about 20 μ

m.

11. The device of claim 7 wherein the carbon-containing material has a thickness of about 0.05 μ

m to about 2.0 μ

m.

12. A device comprising a biocompatible coating for contact with body tissue, the device comprising:

a) a substrate;

b) an intermediate coating of a metal or a ceramic adhered, to the substrate and comprising a plurality of discrete columnar structures, each of the columns having a sidewall extending between a proximal end adhered to the substrate and a distal end spaced therefrom, wherein the sidewalls of immediately adjacent columns do not contact each other to thereby provide an area of the substrate between adjacent columns that is not contacted by the intermediate coating serving as porosity adapted for receiving an elutable material between the columns;

c) a cap of a carbon-containing material provided on the distal end of each of the plurality of columnar structures; and

d) wherein stress levels between immediately adjacent columnar structures are sufficiently within elastic limits of the substrate such that delamination upon expansion of the substrate is substantially precluded.

13. The device of claim 12 wherein the intermediate coating is selected from the group consisting of carbides, oxides, nitrides, oxynitrides, and carbonitrides of titanium, boron, aluminum, calcium, gold, hafnium, iridium, molybdenum, niobium, platinum, rhenium, ruthenium, silicon, silver, tantalum, titanium, tungsten, yttrium, zirconium.

14. The device of claim 12 wherein the carbon-containing material is selected from an amorphous carbon and a diamond-like carbon.

15. The device of claim 12 wherein the intermediate coating is adhered to the substrate and the carbon-containing material is provided as the cap on the distal end of each of the plurality of columnar structures by one of the deposition techniques selected from the group consisting of sputtering, chemical vapor deposition, pulsed laser deposition, reactive evaporation, and as a thermal spray.

16. The device of claim 12 wherein the plurality of columnar structures comprising the intermediate coating each have a length of about 0.1 μ

m to about 20 μ

m.

17. The device of claim 12 wherein the carbon-containing material has a thickness of about 0.05 μ

m to about 2.0 μ

m.