Drug coating with topcoat

• US 6,284,305 B1
• Filed: 05/18/2000
• Issued: 09/04/2001
• Est. Priority Date: 06/13/1996
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Schneider Electric SE
• Inventors: Helmus, Michael N., Ding, Ni
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): MICHENER, JENNIFER KOLB
• Application Number:
  US09/573,506
• Time in Patent Office: 474 Days
• Field of Search: 427/2.24, 427/2.25, 427/2.28, 427/2.3, 427/409, 427/261, 427/407.1
• US Class Current: 427/2.28
• 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 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 2300/236 Glycosaminoglycans, e.g. heparin, hyaluronic acid, chondroitin
• CPC Class Codes: A61L 2300/406 Antibiotics
• 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 2300/602 Type of release, e.g. controlled, sustained, slow
• CPC Class Codes: A61L 2300/606 Coatings
• 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 27/227 Other specific proteins or polypeptides not covered by A61L27/222, A61L27/225 or A61L27/24
• CPC Class Codes: A61L 31/08 Materials for coatings
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/141 Plasticizers
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: A61L 33/0011 Anticoagulant, e.g. heparin, platelet aggregation inhibitor, fibrinolytic agent, other than enzymes, attached to the substrate
• CPC Class Codes: C08L 5/00 Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00
• CPC Class Codes: C08L 71/02 : Polyalkylene oxides
• CPC Class Codes: C08L 83/00 : Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 : Polysiloxanes
• CPC Class Codes: C08L 83/08 : containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen

Abstract

A coating and method for a coating an implantable device or prostheses are disclosed. The coating includes an undercoat of polymeric material containing an amount of biologically active material, particularly heparin, dispersed therein. The coating further includes a topcoat which covers less than the entire surface of the undercoat and wherein the topcoat comprises a polymeric material substantially free of pores and porosigens. The polymeric material of the topcoat can be a biostable, biocompatible material which provides long term non-thrombogenicity to the device portion during and after release of the biologically active material.

Claims

1. A method of coating an implantable stent prosthesis having at least a portion which is implantable into the body of a patient, wherein at least a part of the stent portion is covered with a coating for release of at least one biologically active material;

the method comprising;

(a) applying an undercoat comprising a polymeric material and the biologically active material to the stent portion wherein the undercoat has a surface; and

(b) applying a discontinuous topcoat which covers less than the entire surface of the undercoat, said topcoat comprising a polymeric material, substantially free of pores and pore-forming materials.

2. The method of claim 1 wherein the polymeric material of the undercoat is a hydrophobic elastomeric material and wherein the polymeric material of the undercoat is a biostable, biocompatible material which provides long term non-thrombogenicity to the stent portion during and after release of the biologically active material.

3. The method of claim 1 wherein the polymeric material of the topcoat is selected from the group consisting of fluorosilicone, polyethylene glycol (PEG), polysaccharides, phospholipids and combinations thereof.

4. The method of claim 1 wherein the topcoat covers from about 5% to 95% of the surface of the undercoat.

5. The method of claim 4 wherein the topcoat covers from about 20% to 85% of the surface of the undercoat.

6. The method of claim 1 wherein the topcoat has an average thickness of about the average particle size of the biologically active material.

7. The method of claim 1 wherein the topcoat has an average thickness of about 1 to 7 microns.

8. The method of claim 7 wherein the topcoat has an average thickness of about 1 to 5 microns.

9. The method of claim 1 wherein the polymeric material of the topcoat is a polymer which is incompatible with the polymeric material of the undercoat such that the discontinuous topcoat is formed.

10. The method of claim 1 which further comprises applying a poor solvent to the topcoat to shrink the polymeric material to form the discontinuous topcoat.

11. The method of claim 1 wherein the Young'"'"'s modulus of the polymeric material of the undercoat and the Young'"'"'s modulus of the polymeric material of the topcoat are different.

12. The method of claim 11 wherein the Young'"'"'s modulus of the polymeric material of the topcoat is greater than the Young'"'"'s modulus of the polymeric material of the undercoat.