Controlling resorption of bioresorbable medical implant material

• US 6,913,765 B2
• Filed: 03/21/2001
• Issued: 07/05/2005
• Est. Priority Date: 03/21/2001
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Li, Jianmin, Baldwin, Samuel, Harrah, Tim
• Primary Examiner(s): Azpuru, Carlos A.
• Application Number:
  US09/813,780
• Publication Number:
  US 20020138154A1
• Time in Patent Office: 1,567 Days
• Field of Search: 424/426, 424/423, 424/422, 424/427, 424/428, 424/430, 424/433, 514/772.3, 604/890.1, 604/891.1
• US Class Current: 424/426
• CPC Class Codes: A61B 17/12113 within an aneurysm
• CPC Class Codes: A61F 2/0004 Closure means for urethra or rectum, i.e. anti-incontinence devices or support slings against pelvic prolapse
• CPC Class Codes: A61F 2/02 Prostheses implantable into the body closure means for urethra or rectum or for artificial body openings therefor A61F2/0004
• CPC Class Codes: A61F 2/04 Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts A61F2/18, A61F2/20 take precedence; devices, other than stent-grafts, providing patency to, or preventing collapsing of, tubular structures of the body other than stent-grafts, e.g. stents A61F2/82; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/009 magnetic
• CPC Class Codes: A61L 2300/00 Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
• CPC Class Codes: A61L 27/40 Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/148 Materials at least partially resorbable by the body
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/12 Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: A61P 43/00 Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00

Abstract

The resorption of a medical implant can be controlled with the use of particles embedded in a resorbable bulk material forming the implant or portion thereof. The implant can be removed from a body of a mammal by natural biological mechanisms after use. The resorption of the implant can involve swelling and/or hydrolyzing of the particles within the implant upon contact with a body fluid such that porosity and flow of fluid within the bulk material of the implant is increased. Resorption of the implant may also involve the use of particles with magnetic properties embedded within the implant such that an applied magnetic field causes the particles to vibrate within the bulk material thereby increasing the porosity and thus the flow of fluid, hence facilitating resorption of the implant. The resorption rate of the implant can be controlled by modulating swelling, hydrolysis, or movement of the embedded particles.

Claims

1. A medical device for use in a mammal comprising:

(a) a bioresorbable bulk material comprising an ionically or covalently crosslinked polymeric material; and

(b) resorbable particles containing an agent that causes swelling of the particles upon contact with a body fluid, said particles embedded in said bioresorbable bulk material and said swelling of the particles causing fragmentation of said bioresorbable bulk material.

2. The medical device of claim 1 wherein said resorbable particles resorb upon contact with a body fluid at a resorption rate that is different from the resorption rate of said bioresorbable bulk material.

3. The medical device of claim 2 wherein the resorption rate of said resorbable particles is greater than the resorption rate of said bioresorbable bulk material.

4. The medical device of claim 1 wherein said bioresorbable bulk material comprises an ionically crosslinked polymeric material.

5. The medical device of claim 1 wherein said bioresorbable bulk material comprises a covalently crosslinked polymeric material.

6. The medical device of claim 4 wherein said ionically crosslinked polymeric material comprises at least one polymer or copolymer made from at least one member of the group consisting of polyacrylic acids, polymethacrylic acid, polyethylene amine, polysaccharides, alginic acid, pectinic acids, carboxy methyl cellulose, hyaluronic acid, heparin, chitosan, carboxymethyl chitosan, carboxymethyl starch, carboxymethyl dextran, heparin sulfate, chondroitin sulfate, cationic starch, and salts thereof.

7. The medical device of claim 4 wherein said ionically crosslinked polymeric material is an ionically crosslinked polymer hydrogel and has a water content of less than 90% by weight and possesses sufficient mechanical strength to serve as a stent, a catheter, a cannula, a plug, a constrictor, a sheet, a filler, a bone anchor, a plate, a rod, a seed, a tube, or a portion thereof.

8. The medical device of claim 1 wherein said medical device is a stent, a catheter, a cannula, a plug, a constrictor, a sheet, a filler, a bone anchor, a plate, a rod, a seed, a tube, or a portion thereof.

9. The medical device of claim 1 wherein each of said resorbable particles comprises an organic compound.

10. The medical device of claim 1 wherein each of said resorbable particles comprises a soluble or degradable inorganic compound.

11. The medical device of claim 9 wherein said organic compound is a sugar or a water soluble organic salt.

12. The medical device of claim 1 wherein each of said resorbable particles comprises an organic or inorganic crystal or powder aggregate.

13. The medical device of claim 1 wherein each of said resorbable particles comprises a water-swellable polymer.

14. The medical device of claim 13 wherein said water-swellable polymer comprises a material selected from the group consisting of polysaccharides, polyglycolic acid, polylactic acid, cellulose derivatives, hyaluronic acid, and colloid/hydrogel.

15. The medical device of claim 1 wherein the size of each of said resorbable particles is from about 5 nm to about 1 mm.

16. The medical device of claim 1 wherein the ratio of said resorbable particles in said bioresorbable bulk material is equal to or less than about 50% by volume.

17. The medical device of claim 1 wherein each of said resorbable particles comprises a polymer selected from the group consisting of polysaccharides, polyglycolic acid, polylactic acid, and polycaprolactone and copolymers of any two or three of glycolic acid, lactic acid, and caprolactone monomers.

33. The medical device of claim 1 wherein said resorbable particles comprise an ionically or covalently crosslinked polymeric material that is the same kind of ionically or covalently crosslinked polymeric material as said bioresorbable bulk material.

34. The medical device of claim 33 wherein said polymeric material of said resorbable particles is crosslinked at a lower ratio than the crosslinking ratio of said polymeric material of said bioresorbable bulk material.

35. The medical device of claim 33 wherein said polymeric material of said resorbable particles and bulk material are crosslinked with ions said ions of said resorbable particles having a weaker electronic affinity than said ions of said bioresorbable material.

18. A method for controlling resorption of a bioresorbable material in a device for use in a mammal, said method comprising:

(a) providing a bioresorbable bulk material comprising an ionically or covalently crosslinked polymeric material;

(b) embedding resorbable particles in said bioresorbable bulk material, said resorbable particles resorbing faster upon contact with a body fluid than said bioresorbable bulk material; and

(c) contacting a body fluid with said bioresorbable bulk material and said resorbable particles, wherein the resorbable particles swell upon contact with said body fluid and cause fragmentation of said bioresorbable bulk material.

19. The method of claim 18 wherein said controllable resorption rate is different from the resorption rate of said bioresorbable bulk material without said embedded resorbable particles.

20. The method of claim 19 wherein said bioresorbable bulk material comprises an ionically crosslinked polymeric material.

21. The method of claim 19 wherein said bioresorbable bulk material comprises a covalently crosslinked polymeric material.

22. The method of claim 19 wherein said resorption rate is controlled by varying the size or the amount of said resorbable particles.

23. The method of claim 19 wherein said resorbable particles hydrolyze into by-products soluble in said body fluid upon contact with said body fluid.

24. A composition for use in a device in a mammal, said composition comprising:

(a) a bioresorbable bulk material comprising an ionically or covalently crosslinked polymeric material; and

(b) resorbable particles containing an agent that causes swelling of the particles upon contact with a body fluid, said particles embedded in said bioresorbable bulk material, and said swelling of the resorbable particles causing fragmentation of said bioresorbable bulk material.

25. The composition of claim 24 wherein the resorption rate of said resorbable particles is greater than the resorption rate of said bioresorbable bulk material.

26. The composition of claim 24 wherein said bioresorbable bulk material comprises an ionically crosslinked polymeric material or a covalently crosslinked polymeric material.

27. The composition of claim 24 wherein each of said resorbable particles comprise an organic compound.

28. The composition of claim 24 wherein each of said resorbable particles comprise a soluble or degradable inorganic compound.

29. The composition of claim 24 wherein each of said resorbable particles comprise organic or inorganic crystals or powder aggregates.

30. The composition of claim 24 wherein each of said resorbable particles comprise a polymer.

31. The composition of claim 24 wherein the size of said resorbable particles is about 5 nm to about 1 mm.

32. The composition of claim 24 wherein the volume percentage of said resorbable particles in said bulk material is equal to or less than about 50%.