Degradable polymeric implantable medical devices with continuous phase and discrete phase

• US 7,923,022 B2
• Filed: 09/13/2006
• Issued: 04/12/2011
• Est. Priority Date: 09/13/2006
• Status: Expired due to Fees

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Wang, Yunbing, Gale, David C.
• Primary Examiner(s): Wax; Robert A
• Assistant Examiner(s): CRAIGO, WILLIAM A
• Application Number:
  US11/521,271
• Publication Number:
  US 20080063685A1
• Time in Patent Office: 1,672 Days
• Field of Search: None
• US Class Current: 424/426
• CPC Class Codes: A61L 31/129 containing macromolecular fillers
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body

Abstract

An implantable medical device is disclosed comprising: a structural element, wherein the structural element includes: a continuous phase comprising a first polymer of LPLG; a discrete phase within the continuous phase, wherein the discrete phase comprises a second polymer including rapidly eroding elastic discrete phase segments. The second polymer further includes anchor segments that have the same or substantially the same chemical make up as the first polymer of the continuous phase, and at least some of the anchor segments have partially or completely phase-separated from the discrete phase into the continuous phase.

Claims

1. An implantable medical device comprising:

a structural element, wherein the structural element includes;

a continuous phase comprising a first polymer of LPLG;

a discrete phase within the continuous phase, wherein the discrete phase comprises a second polymer including discrete phase segments;

the second polymer further includes anchor segments that have the same or substantially the same chemical make up as the first polymer of the continuous phase, and at least some of the anchor segments have partially or completely phase-separated from the discrete phase into the continuous phase.

2. The device according to claim 1, wherein the implantable medical device is a stent.

3. The device according to claim 1, wherein the discrete phase segments have a T_g below body temperature.

4. The device according to claim 1, wherein the discrete phase is more flexible than the continuous phase at body temperature.

5. The device according to claim 1, wherein the anchor segments are miscible with the first polymer.

6. The device according to claim 1, wherein the second polymer comprises P(GA-co-CL)-b-LPLG.

7. The device according to claim 1, wherein 5-20 wt % of the structural element comprises the second polymer.

8. The device according to claim 1, wherein the discrete phase segments degrade to acidic fragments.

9. The device according to claim 1, wherein the discrete phase segments degrade to hydrophilic fragments.

10. An implantable medical device, comprising:

a structural element fabricated of a blend that includes about 60 to about 99 wt % of a first polymer of LPLG, wherein the first polymer forms a continuous phase; and

about 1 to about 40 wt % of a second polymer, the second polymer forming a discrete phase within the continuous phase, wherein the second polymer having a T_g below body temperature comprises discrete phase segments that degrade to acidic fragments,

the second polymer further comprises anchor segments having the same or substantially the same chemical make up as the continuous phase, wherein the anchor segment has phase-separated out from the discrete phase into the continuous phase.

11. The device according to claim 10, wherein the second polymer is P(GA-co-CL)-b-LPLG.

12. The device according to claim 10, wherein the anchor segment is selected from the group consisting of LPLG and materials that are miscible in LPLG.

13. An implantable medical device, comprising:

a structural element fabricated of a blend that includes;

about 60 to about 99 wt % of a first polymer of LPLG, wherein the first polymer forms a continuous phase;

about 1 to about 10 wt % of a second polymer, the second polymer forming a discrete phase within the continuous phase, the second polymer comprising discrete phase segments and anchor segments, wherein anchor segments have the same or substantially the same chemical make up as the first polymer of the continuous phase and have phase-separated out from the discrete phase into the continuous phase; and

about 5 to about 30 wt % of a third polymer having a T_g below body temperature consisting essentially of discrete phase segments, wherein the third polymer degrades into fragments at least some of which are acidic.

14. The device according to claim 13, wherein the second polymer is P(GA-co-CL)-b-LPLG copolymer.

15. The device according to claim 13, wherein the anchor segments are LPLG.

16. The device according to claim 13, wherein the third polymer is P(GA-co-CL) copolymer.

17. A composition comprising:

a continuous phase comprising a first polymer of LPLG;

a discrete phase within the continuous phase, wherein the discrete phase comprises a second polymer including discrete phase segments;

the second polymer further includes anchor segments that have the same or substantially the same chemical make up as the first polymer of the continuous phase, and at least some of the anchor segments have partially or completely phase-separated from the discrete phase into the continuous phase.

18. The composition to claim 17, wherein the anchor segments are miscible with the first polymer.

19. The composition to claim 17, wherein the discrete phase comprise P(GA-co-CL) copolymer.

20. The composition to claim 17, wherein the second polymer comprises P(GA-co-CL)-b-LPLG.

21. The composition to claim 17, wherein the discrete phase segments comprise two or more of the following monomers in any proportion:

glycolide, caprolactone, and trimethylene carbonate.

22. A method of forming a copolymer comprising:

mixing glycolide monomers, caprolactone monomers, a catalyst, and a solvent to form a solution, wherein the glycolide and caprolactone monomers react in the solution to form P(GA-co-CL); and

adding L-lactide monomers and glycolide monomers and allowing the added monomers to react with P(GA-co-CL) to form P(GA-co-CL)-b-LPLG.

23. The method according to claim 22, wherein the L-lactide monomers and glycolide monomers are allowed to react with the P(GA-co-CL) in the presence of a solvent, wherein the solvent is the same or different solvent used to form the P(GA-co-CL).

24. The method according to claim 22, wherein the solvent is devoid of alcohol functional groups.

25. The method according to claim 22, wherein the solvent is selected from the group consisting of chloroform, toluene, xylene, cyclohexane, and any mixture thereof in any proportion.

26. A method of forming a copolymer comprising:

mixing glycolide monomers, L-lactide monomers, a catalyst, and a solvent to form a solution, wherein the glycolide and L-lactide monomers react in the solution to form LPLG; and

adding caprolactone monomers and glycolide monomers and allowing the added monomers to react with LPLG to form LPLG-b-P(GA-co-CL).

27. The method according to claim 26, wherein the caprolactone monomers and glycolide monomers are allowed to react with the LPLG in the presence of a solvent, wherein the solvent is the same or different solvent used to form the LPLG.

28. The method according to claim 26, wherein the solvent is devoid of alcohol functional groups.

29. The method according to claim 26, wherein the solvent is selected from the group consisting of chloroform, toluene, xylene, cyclohexane, and any mixture thereof in any proportion.

30. A copolymer comprising P(GA-co-CL)-b-LPLG.

31. A copolymer comprising LPLG-b-P(GA-co-CL).