Intravascular stent and method

• US 5,624,411 A
• Filed: 06/07/1995
• Issued: 04/29/1997
• 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): Green, Randall L.
• Assistant Examiner(s): VANOVER, PERRY
• Application Number:
  US08/483,005
• Time in Patent Office: 692 Days
• Field of Search: 604/28, 604/92-93, 604/83, 604/51-53, 604/48-49, 604/891.1, 604/264-266, 606/191-194, 600/36, 623/1, 623/12
• US Class Current: 604/265
• 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 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 2300/222 Steroids, e.g. corticosteroids
• 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 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 making an intravascular stent by applying to the body of a stent a therapeutic substance and then overcoating the therapeutic substance with a porous polymer. The inclusion of a porous polymer in intimate contact with a drug on the stent allows the drug to be retained on the stent during expansion of the stent and also controls the administration of drug following implantation. The adhesion of the coating and the rate at which the drug is delivered can be controlled by the selection of an appropriate bioabsorbable or biostable polymer.

Claims

1. A device for delivery of a drug into a body lumen comprising:

(a) a generally cylindrical, radially expandable stent body;

(b) a coating on the stent body a first coating layer comprising a therapeutic substance and a second coating layer comprising a porous polymer overlaying the first coating layer;

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

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

2. A device according to claim 1 wherein the stent body has a metal surface.

3. A device according to claim 1 wherein the stent body has a polymeric surface.

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

5. A device 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 device according to claim 1 wherein the polymer is a biostable polymer.

7. A device 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 device according to claim 1 wherein the drug 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 device according to claim 1 in which the porous polymer has average pore diameter in the range of about 0.5-10 microns.

10. 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;

(b) providing as a coating on the stent body a first coating layer comprising a therapeutic substance and a second coating layer comprising a porous polymer overlaying the first coating layer;

(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.

11. A method according to claim 10 wherein the stent body has a metal surface.

12. A method according to claim 10 wherein the stent body has a polymeric surface.

13. A method according to claim 10 wherein the polymer is a bioabsorbable polymer.

14. A method according to claim 13 wherein the polymer is selected from the group consisting of poly(lactic acid), poly(lactide-co-glycolide) and poly(hydroxybutyrate-co-valerate).

15. A method according to claim 10 wherein the polymer and therapeutic agent are in a solid/solid solution.

16. A method according to claim 10 wherein the polymer is a biostable polymer.

17. A method according to claim 16 wherein the polymer is selected from the group consisting of silicones, polyurethanes, polyesters, vinyl homopolymers and copolymers, acrylate homopolymers and copolymers, polyethers and cellulosics.

18. A method according to claim 10 wherein the drug is selected from the group consisting of glucocorticoids, dexamethasone, dexamethasone sodium phosphate, anticoagulants, heparin, hirudin, tick anticoagulant peptide, angiopeptin, antimitotic agents, and oligonucleotides.

19. A method for providing a stent having a therapeutic substance thereon comprising the steps of:

(a) providing a cylindrical, radially expandable stent body;

(b) applying to the stent body a solution which includes a solvent and a therapeutic substance dispersed in the solvent;

(c) evaporating the solvent;

(d) applying to the therapeutic substance on the stent body an overlayer of a polymer by the steps of;

(1) applying to the stent body a solution which includes a solvent and the polymer dissolved in the solvent;

(2) evaporating the solvent to produce pores in the resulting polymer coating; and

(e) radially expanding the stent body, applied polymer and therapeutic substance such that the polymer and therapeutic substance are retained on the stent body.

20. A method according to claim 19 wherein the overlayer is applied by spraying.

21. A method according to claim 19 wherein the overlayer is applied by immersion.

22. A method according to claim 19 wherein the polymer is a bioabsorbable polymer.

23. A method according to claim 22 wherein the polymer is selected from the group consisting of poly(lactic acid), poly(lactide-co-glycolide) and poly(hydroxybutyrate-co-valerate).

24. A method according to claim 19 wherein the polymer is a biostable polymer.

25. A method according to claim 24 wherein the polymer is selected from the group consisting of silicones, polyurethanes, polyesters, vinyl homopolymers and copolymers, acrylate homopolymers and copolymers, polyethers and cellulosics.

26. A method according to claim 19 wherein the solution for applying the overlayer includes a solvent mixture, the solvent mixture including a first solvent in which the polymer has a solubility and a second solvent in which the polymer has a lesser solubility.

27. A method according to claim 19 wherein the drug is selected from the group consisting of glucocorticoids, dexamethasone, dexamethasone sodium phosphate, anticoagulants, heparin, hirudin, tick anticoagulant peptide, angiopeptin, antimitotic agents, and oligonucleotides.