Implantable medical devices fabricated from branched polymers

• US 20070282435A1
• Filed: 04/09/2007
• Published: 12/06/2007
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Wang, Yunbing, Gale, David C., Glauser, Thierry, Huang, Bin, Trollsas, Mikael O., Ludwig, Florian
• Granted Patent: US 8,486,135 B2
• Time in Patent Office: Days
• US Class Current: 623/1.380
• CPC Class Codes: A61L 27/14 Macromolecular materials
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 31/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

Implantable medical devices fabricated from branched polymers are disclosed.

Claims

1. A stent fabricated at least in part from a polymeric material comprising a branched biodegradable polymer, the structure of the branched biodegradable polymer selected from the group consisting of hyperbranched-like polymers, comb-like polymers, star polymers, dendrimer-like star polymers, dendrimers, or any mixture thereof in any proportion.

2. The stent of claim 1, wherein the biodegradable polymer comprises a random copolymer.

3. The stent of claim 1, wherein biodegradable polymer comprises a block copolymer.

4. The stent of claim 1, wherein the polymer is an aliphatic polyester selected from the group consisting of poly(L-lactide), poly(DL-lactide), polyglycolide, poly(lactic-co-glycolic acid), poly(ε

-caprolactone), poly(hydroxy butyrate), poly(trimethylene carbonate), polydioxanone, and any blends or copolymers thereof.

5. The stent of claim 1, wherein the polymer is selected from the group consisting of poly(ester amides), polypeptides, polyethylene glycol, and any blends or copolymers thereof.

6. The stent of claim 1, wherein the polymer is selected from the group consisting of polyacrylates, polymethacrylates, polypropylene oxides, polysaccharides, polyamide, and any blends or copolymers thereof.

7. A stent fabricated from a polymeric material comprising an unbranched biodegradable polymer blended with a branched biodegradable polymer, wherein a majority of the polymeric material comprises the unbranched polymer.

8. The stent of claim 7, wherein the polymeric material comprises greater than 95 wt % of the unbranched polymer.

9. The stent of claim 7, wherein the branched polymer is a star copolymer, wherein the star copolymer reduces the viscosity of the polymeric material when above a melting temperature of the polymeric material.

10. The stent of claim 7, wherein the unbranched polymer is selected from the group consisting of poly(L-lactide), poly(DL-lactide), poly(lactic-co-glycolic acid), poly(ε

-caprolactone), and any blends or copolymers thereof.

11. The stent of claim 7, wherein the branched polymer is selected from the group consisting of poly(L-lactide), poly(DL-lactide), poly(lactic-co-glycolic acid), poly(ε

-caprolactone), and any blends or copolymers thereof.

12. An implantable medical device fabricated from a polymer blend comprising:

a biodegradable matrix polymer blended with biodegradable star-block copolymers having at least three arms, wherein the arms include inner segments and outer segments, the inner segments forming a discrete phase within a continuous phase, the continuous phase including the matrix polymer and the outer segments.

13. The device of claim 12, wherein the implantable medical device is a stent.

14. The device of claim 12, wherein the star-block copolymers are dispersed throughout the polymer matrix.

15. The device of claim 12, wherein the inner segments are faster degrading than the outer segment.

16. The device of claim 12, wherein the outer segments are of the same or similar chemical composition as the matrix polymer.

17. The device of claim 12, wherein the inner segments have a Tg below body temperature and the outer segments have a Tg above body temperature.

18. The device of claim 12, wherein the inner segments are elastic at physiological conditions.

19. The device of claim 12, wherein the outer segments are glassy at physiological conditions.

20. The device of claim 12, wherein the matrix polymer and the outer segments comprise PLLA.

21. The device of claim 12, wherein the inner segments comprise units selected from the group consisting of CL, TMC, and dioxanone.

22. The device of claim 12, wherein the star-block copolymer comprises P(CL-co-TMC)-b-PLLA.

23. The device of claim 12, wherein 1 to 20 wt % of the polymer blend comprises the star-block copolymer.

24. A method of fabricating an implantable medical device comprising:

forming star-block copolymers having at least three arms, wherein the arms include inner segments and outer segments;

blending a matrix polymer with the star-block copolymers, wherein the blend comprises discrete phase regions dispersed within the continuous phase, the continuous phase comprising the matrix polymer and the outer segments, the discrete phase regions comprising the inner segments; and

fabricating an implantable medical device from the blend.

25. The device of claim 24, wherein the implantable medical device is a stent.