Method for delivering a therapeutic substance to a body lumen

• US 5,824,048 A
• Filed: 10/09/1996
• Issued: 10/20/1998
• Est. Priority Date: 04/26/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Tuch, Ronald J.
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US08/731,106
• Time in Patent Office: 741 Days
• Field of Search: 623/1, 623/12, 427/2.25, 427/2.3, 606/191
• US Class Current: 128/898
• 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 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 2300/43 Hormones, e.g. dexamethasone
• CPC Class Codes: A61L 2300/608 having two or more layers
• 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 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence

Abstract

A method for delivering a therapeutic substance to a body lumen utilizing an intravascular stent having a coating comprising a polymer and a therapeutic substance in a solid/solid solution with the polymer. The coating comprises a first coating layer nearer the stent body having a first concentration of therapeutic substance overlaid by a second porous coating layer having a second lesser concentration of therapeutic substance. The inclusion of a porous polymer coating layer on the stent helps retain the therapeutic substance on the stent during expansion of the stent and also controls the administration of the therapeutic substance following implantation. By this method, drugs such as dexamethasone can be applied to a stent, retained on a stent during expansion of the stent and elute at a controlled rate.

Claims

1. A method for delivery of a therapeutic substance to the interior of a body lumen comprising the steps of:

(a) providing a generally cylindrical stent body having a surface;

(b) providing a coating on the surface of the stent body comprising a polymer and a therapeutic substance in a solid/solid solution with the polymer, the coating further comprising a first coating layer nearer the stent body having a first concentration of therapeutic substance overlaid by a second porous coating layer having a second lesser concentration of therapeutic substance;

(c) introducing the stent transluminally into a selected portion of the body lumen; and

(d) radially expanding the stent into contact with the body lumen.

2. A method according to claim 1 wherein the surface of the stent body is a metal surface.

3. A method according to claim 1 wherein the first coating layer is porous and the second coating layer is more porous than the first coating layer.

4. A method according to claim 1 wherein the polymer is a bioabsorbable polymer.

5. A method according to claim 4 wherein the polymer is selected from the group consisting of poly(lactic acid), poly(lactide-co-glycolide) and poly(hydroxybutyrate-co-valerate).

6. A method according to claim 1 wherein the polymer is a biostable polymer.

7. A method according to claim 6 wherein the polymer is selected from the group consisting of silicones, polyurethanes, polyesters, vinyl homopolymers and copolymers, acrylate homopolymers and copolymers, polyethers and cellulosics.

8. A method according to claim 1 wherein the therapeutic substance is selected from the group consisting of glucocorticoids, dexamethasone, dexamethasone sodium phosphate, anticoagulants, heparin, hirudin, tick anticoagulant peptide, angiopeptin, antimitotic agents, and oligonucleotides.

9. A method according to claim 1 wherein the second coating layer is the product of phase inversion precipitation of the polymer.