Implantable medical device with drug filled holes
View Patent ↗The present invention relates to implantable medical devices for delivery of therapeutic agents, such as drugs, to a patient. More particularly, the invention relates to a device having therapeutic agents protected by a protective layer that prevents or retards processes that deactivate or degrade the active agents.
1. An implantable medical device comprising:
an implantable device body having a plurality of through holes therein;
a barrier formed in the plurality of through holes, the barrier formed of a biodegradable copolymer having a first copolymer ratio;
a drug filled portion formed in the plurality of through holes adjacent the barrier; and
a cap formed in the plurality of through holes adjacent the drug filled portion, the cap formed of the biodegradable copolymer having a second copolymer ratio, wherein the second copolymer ratio is different from the first copolymer ratio, and wherein the barrier is formed adjacent a luminal surface of the implantable device body, the cap is formed adjacent a mural surface of the implantable device body, and the cap degrades faster than the barrier.
2. The device of claim 1 , wherein the implantable medical device is a stent.
3. The device of claim 2 , wherein the drug filled portion comprises a drug for prevention of restenosis.
4. The device of claim 1 , wherein the barrier, the drug filled portion, and the cap are formed by loading compositions dropwise into the through holes.
5. The device of claim 1 , wherein the biodegradable copolymer is poly(lactide-co-glycolide).
6. The device of claim 5 , wherein the first copolymer ratio is 85:15.
7. The device of claim 5 , wherein the second copolymer ratio is 50:50.
8. The device of claim 1 , wherein the first and second copolymer ratios are selected such that following implantation the cap degrades faster than the barrier.
9. The device of claim 1 , wherein the drug filled portion includes a limus drug.
10. The device of claim 1 , wherein the drug filled portion includes a water sensitive drug.
11. A method of forming an implantable medical device comprising:
forming an implantable device body having a plurality of through holes therein;
loading a mixture of a biodegradable copolymer having a first copolymer ratio and a first solvent into the holes and evaporating the first solvent to form a barrier;
loading a mixture of a drug, a polymer, and a second solvent into the holes and evaporating the second solvent to form a drug portion; and
loading a mixture of the biodegradable copolymer having a second copolymer ratio and a third solvent into the holes and evaporating the third solvent to form a cap, wherein the second copolymer ratio is different from the first copolymer ratio, and wherein the barrier is formed adjacent a luminal surface of the implantable device body, the cap is formed adjacent a mural surface of the implantable device body, and the cap degrades faster than the barrier.
12. The method of claim 11 , wherein the first, second, and third solvents are the same.
13. The method of claim 11 , wherein the implantable medical device is a stent.
14. The method of claim 11 , wherein the drug comprises a drug for prevention of restenosis.
15. The method of claim 11 , wherein the loading steps include loading the mixtures dropwise into the through holes.
16. The method of claim 11 , wherein the biodegradable copolymer is poly(lactide-co-glycolide).
17. The method of claim 16 , wherein the first copolymer ratio is 85:15.
18. The method of claim 16 , wherein the second copolymer ratio is 50:50.
19. The method of claim 11 , wherein the first and second copolymer ratios are selected such that following implantation the cap degrades faster than the barrier.
20. The method of claim 11 , wherein the drug comprises a limus drug.
21. The method of claim 11 , wherein the drug comprises a water sensitive drug.