Stent and delivery system with reduced chemical degradation

• US 8,147,769 B1
• Filed: 05/16/2007
• Issued: 04/03/2012
• Est. Priority Date: 05/16/2007
• Status: Expired due to Fees

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Huang, Bin, Kleiner, Lothar W., Stankus, John
• Primary Examiner(s): Joyner, Kevin
• Application Number:
  US11/804,234
• Time in Patent Office: 1,784 Days
• Field of Search: 422/22, 422/243
• US Class Current: 422/243
• CPC Class Codes: A61L 2/08 Radiation
• CPC Class Codes: A61L 2/081 Gamma radiation
• CPC Class Codes: A61L 2/087 Particle radiation, e.g. electron-beam, alpha or beta radiation
• CPC Class Codes: A61L 2300/30 Compounds of undetermined constitution extracted from natural sources, e.g. Aloe Vera
• CPC Class Codes: A61L 2300/428 Vitamins, e.g. tocopherol, riboflavin
• 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 31/04 Macromolecular materials
• CPC Class Codes: A61L 31/042 Polysaccharides
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence

Abstract

Stents and delivery systems with reduced chemical degradation and methods of sterilizing the same are disclosed.

Claims

1. A stent comprising:

a substrate;

a coating comprising a polymer over the substrate; and

a chemical degradation-reducing substance that reduces or prevents chemical degradation in a polymeric portion of the stent, the chemical degradation arising from exposure to radiation during sterilization,

wherein the substance comprises a polymeric or oligomeric antioxidant or free radical scavenger selected from the group consisting of chitooligosaccharides obtained by partial chitosan hydrolysis.

2. The stent of claim 1, wherein the radiation comprises e-beam or gamma radiation.

3. The stent of claim 1, wherein the substrate comprises a biostable or bioabsorbable polymer, the substance being dispersed within the substrate.

4. The stent of claim 1, wherein the substance is dispersed within the coating.

5. The stent of claim 1, wherein the substance is dispersed within a substance layer of the coating, the substance layer being disposed above or below a drug-polymer layer of the coating.

6. The stent of claim 1, wherein the substance further comprises a free radical scavenger or antioxidant selected from the group consisting of L-ascorbate, Vitamin E, herbal rosemary, sage extracts, butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, tertbutylhydroquinone, and combinations thereof.

7. The stent of claim 1, wherein some of the polymeric or oligomeric antioxidant or free radical scavenger are bonded or grafted to the coating polymer.

8. A stent delivery assembly comprising a polymeric portion of the assembly, the polymeric portion including a chemical degradation-reducing substance that reduces or prevents chemical degradation in the polymeric portion arising from exposure to radiation during sterilization,

wherein the substance comprises a polymeric or oligomeric free radical scavenger selected from the group consisting of chitooligosaccharides obtained by partial chitosan hydrolysis.

9. The assembly of claim 8, wherein the radiation comprises e-beam or gamma radiation.

10. The assembly of claim 8, wherein the polymeric portion comprises a catheter, the substance being dispersed within the polymer of the catheter.

11. The assembly of claim 8, wherein the polymeric portion comprises a coating above a catheter, stent delivery balloon, or restraining sheath disposed over a stent disposed over the catheter, the coating comprising the substance dispersed within the coating.

12. The assembly of claim 8, wherein the polymeric portion comprises a restraining sheath disposed over a stent, the substance being dispersed within the polymer of the restraining sheath.

13. The assembly of claim 8, wherein the polymeric portion comprises a balloon, the substance being dispersed within the polymer of the balloon.

14. The assembly of claim 8, wherein the chemical degradation comprises reactions of free radicals with the polymer of the polymeric portion, the substance reducing or preventing the reactions.

15. The assembly of claim 8, wherein the substance further comprises a free radical scavenger or antioxidant selected from the group consisting of L-ascorbate, Vitamin E, herbal rosemary, sage extracts, butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, tertbutylhydroquinone, and combinations thereof.

16. The assembly of claim 8, wherein some of the polymeric or oligomeric antioxidant or free radical scavenger are bonded or grafted to the polymer of the polymeric portion.