Thermal treatment of a drug eluting implantable medical device

• US 7,682,647 B2
• Filed: 06/25/2003
• Issued: 03/23/2010
• Est. Priority Date: 09/03/1999
• Status: Expired due to Fees

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Hu, Ty, Scheinpflug, Kurt, Pacetti, Stephen D., Hossainy, Syed F. A., Tang, Fuh-Wei, Royal, Jeff, Happ, Dorie M.
• Primary Examiner(s): Meeks; Timothy H
• Assistant Examiner(s): Sellman; Cachet I
• Application Number:
  US10/603,794
• Publication Number:
  US 20040220665A1
• Time in Patent Office: 2,463 Days
• Field of Search: 427 21- 224, 623/1.1, 623/1.15, 623/1.42, 623/1.44, 623/1.46
• US Class Current: 427/2.1
• 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: A61L 2300/416 Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus
• 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 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• 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
• 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: A61P 31/04 Antibacterial agents
• CPC Class Codes: A61P 37/00 Drugs for immunological or allergic disorders
• CPC Class Codes: A61P 43/00 Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• CPC Class Codes: A61P 9/10 for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
• CPC Class Codes: A61P 9/14 Vasoprotectives; Antihaemorrhoidals; Drugs for varicose therapy; Capillary stabilisers
• CPC Class Codes: C08L 29/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids

Abstract

A coating and a method of coating an implantable medical device, such as a stent, is disclosed. The method includes subjecting the coating to a thermal condition which can result in reduction of the rate of release of an active agent from the coating subsequent to the implantation of the device.

Claims

1. A method of manufacturing a stent coating, comprising:

applying a composition to a stent, the composition including a polymer and a solvent;

allowing the solvent to evaporate to form a coating; and

exposing the coating to a temperature equal to or greater than the glass transition temperature of the polymer for a duration of time, wherein the polymer is a semicrystalline polymer having about 40 to 75 percent crystallinity prior to the act of exposing.

2. The method of claim 1, wherein the composition further includes an active agent.

3. The method of claim 2, further comprising forming a primer layer on the stent prior to applying the composition to the stent.

4. The method of claim 2, further comprising forming a barrier layer over the coating prior to exposing the coating to the temperature.

5. The method of claim 2, further comprising forming a barrier layer over the coating subsequent to exposing the coating to the temperature.

6. The method of claim 2, wherein the active agent is of a type that does not adversely degrade when exposed to the temperature.

7. The method of claim 2, wherein the act of exposing does not reduce the total content of the active agent in the coating.

8. The method of claim 2, wherein the active agent is rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, or a functional analog or structural derivative thereof.

9. The method of claim 1, wherein the solvent is allowed to evaporate to form a dry coating comprising less than about 2% residual fluid content (w/w).

10. The method of claim 9, wherein the dry coating comprises less than about 1% residual fluid content (w/w).

11. The method of claim 1, wherein the temperature is below the melting temperature of the polymer.

12. The method of claim 1, wherein the composition additionally includes an additive for shifting the glass transition temperature or the melting temperature of the polymer to a temperature different than the actual glass transition temperature or the melting temperature of the polymer without the additive.

13. The method of claim 1, wherein the polymer comprises an ethylene vinyl alcohol copolymer, an ethylene-vinyl acetate copolymer, poly(butylmethacrylate), or a combination of the same.

14. The method of claim 1, wherein the temperature is equal to the glass transition temperature of the polymer plus the melting temperature of the polymer, divided by 2.

15. The method of claim 1, wherein the temperature is equal to 0.9 times the melting temperature of the polymer, wherein the melting temperature of the polymer is expressed in Kelvin.

16. The method of claim 1, wherein the glass transition temperature is determined by a method selected from the group consisting of dilatometry, differential thermal analysis, differential scanning calorimetry, brillouin light scattering, local thermal analysis, ellipsometry and x-ray reflectivity.

17. The method of claim 1, wherein the polymer is a blend of two or more polymers.

18. The method of claim 1, wherein the polymer is a block copolymer.

19. The method of claim 1, wherein the polymer is a graft copolymer.

20. The method of claim 1, wherein the polymer exhibits two or more glass transition temperatures, and wherein the method includes exposing the polymer to a temperature equal to or greater than the lowest exhibited glass transition temperature.

21. The method of claim 1, wherein the polymer exhibits two or more glass transition temperatures, and wherein the method includes exposing the polymer to a temperature equal to or greater than the highest exhibited glass transition temperature.