Rate limiting barriers for implantable medical devices

• US 20040072922A1
• Filed: 10/09/2002
• Published: 04/15/2004
• Est. Priority Date: 10/09/2002
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Hossainy, Syed F.A., Dehnad, Houdin, Tang, Fuh-Wei
• Granted Patent: US 7,087,263 B2
• Time in Patent Office: Days
• US Class Current: 523/113
• CPC Class Codes: A61L 2420/08 Coatings comprising two or more layers
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• 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 for a medical device, particularly for a drug eluting stent, is described. The coating comprises a polymer having a weight-average molecular weight between about 200,000 and about 250,000 Daltons or a polydispersity index between about 2.6 and about 3.0.

Claims

1. A coating for an implantable medical device, the coating comprising poly(ethylene-co-vinyl alcohol) having a weight-average molecular weight between about 200,000 and about 250,000 Daltons.

2. The coating of claim 1, wherein the implantable medical device is a stent.

3. The coating of claim 1, additionally comprising a therapeutic substance.

4. The coating of claim 3, wherein the therapeutic substance is selected from a group consisting of rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, 40-O-(3-hydroxy)propyl-rapamycin, 40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, and 40-O-tetrazole-rapamycin.

5. The coating of claim 1, wherein poly(ethylene co-vinyl alcohol) further has a polydispersity index between about 2.6 and about 3.0.

6. The coating of claim 1, wherein the coating comprises a first layer and a second layer disposed over the first layer, wherein the first layer is made from a polymer and a therapeutic substance and the second layer is made from the poly(ethylene-co-vinyl alcohol) having a weight-average molecular weight between about 200,000 and about 250,000 Daltons.

7. The coating of claim 6, wherein a ratio between the therapeutic substance and the polymer in the first layer is between about 1:

1 and about 1;

25.

8. A coating for an implantable medical device, the coating comprising poly(ethylene-co-vinyl alcohol) having a polydispersity index between about 2.6 and about 3.0.

9. The coating of claim 8, wherein the implantable medical device is a stent.

10. The coating of claim 8, additionally comprising a therapeutic substance.

11. The coating of claim 10, wherein the therapeutic substance is selected from a group consisting of rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, 40-O-(3-hydroxy)propyl-rapamycin, 40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, and 40-O-tetrazole-rapamycin.

12. The coating of claim 8, wherein the coating comprises a first layer and a second layer disposed over the first layer, wherein the first layer is made from a polymer and a therapeutic substance and the second layer is made from the poly(ethylene-co-vinyl alcohol) having a polydispersity index between about 2.6 and about 3.0.

13. The coating of claim 12, wherein a ratio between the therapeutic substance and the polymer in the first layer is between about 1:

1 and about 1;

25.

14. A coating for an implantable medical device, the coating comprising a first layer containing a polymer and a therapeutic substance, wherein a ratio between the therapeutic substance and the polymer in the first layer is between about 1:

1 and about 1;

25.

15. The coating of claim 14, wherein the implantable medical device is a stent.

16. The coating of claim 14, wherein the therapeutic substance is selected from a group consisting of rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, 40-O-(3-hydroxy)propyl-rapamycin, 40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, and 40-O-tetrazole-rapamycin.

17. The coating of claim 14, additionally comprising a second layer disposed over the first layer, the second layer comprising poly(ethylene-co-vinyl alcohol) having a weight-average molecular weight between about 200,000 and about 250,000 Daltons or a polydispersity index between about 2.6 and about 3.0.

18. A method of coating a stent comprising forming a coating comprising a copolymer of ethylene and vinyl alcohol on the stent, the copolymer having a weight-average molecular weight between about 200,000 and about 250,000 Daltons or a polydispersity index between about 2.6 and about 3.0.

19. The method of claim 18, wherein the coating further comprises a first layer containing a polymer and a therapeutic substance incorporated therein.

20. The method of claim 19, wherein the therapeutic substance is selected from a group consisting of rapamycin, 40-O-(2-hydroxy)ethyl-rapamycin, 40-O-(3-hydroxy)propyl-rapamycin, 40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, and 40-O-tetrazole-rapamycin.