Self-buffering medical implants

• US 8,267,992 B2
• Filed: 03/02/2010
• Issued: 09/18/2012
• Est. Priority Date: 03/02/2009
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Atanasoska, Liliana, Shippy, James Lee III, Holman, Tom, Arney, Michael S., Schoenle, Victor, Genovese, Frank, Feng, James Q., Flanagan, Aiden, Weber, Jan
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): SCHALL, MATTHEW WAYNE
• Application Number:
  US12/715,577
• Publication Number:
  US 20100222873A1
• Time in Patent Office: 931 Days
• Field of Search: 623 142- 146, 623/1.38, 606/77
• US Class Current: 623/1.42
• CPC Class Codes: A61L 2300/416 Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus
• CPC Class Codes: A61L 2300/604 Biodegradation
• CPC Class Codes: A61L 2400/12 Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
• CPC Class Codes: A61L 2420/04 Coatings containing a composite material such as inorganic/organic, i.e. material comprising different phases
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/446 with other specific inorganic fillers other than those covered by A61L27/443 or A61L27/46
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/128 containing other specific inorganic fillers not covered by A61L31/126 or A61L31/127
• 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: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

A medical implant includes a bioerodible portion that includes a bioerodible polymer and a bioerodible metal. The bioerodible polymer matrix degrades under physiological conditions to form acidic degradation products. The bioerodible metal degrades under physiological conditions to form basic degradation products. The acidic degradation products and the basic degradation products buffer at least a portion of the medical implant. In one aspect, the bioerodible portion includes a bioerodible polymer matrix and a bioerodible metal within the bioerodible polymer matrix. In another aspect, the medical implant can include a body, a plurality of discrete deposits of the bioerodible polymer on the body, and a plurality of discrete deposits of the bioerodible metal on the body.

Claims

1. A medical implant comprising a bioerodible portion comprising:

a bioerodible polymer matrix that degrades under physiological conditions to form acidic degradation products; and

a bioerodible metal within the bioerodible polymer matrix, wherein the bioerodible metal degrades under physiological conditions to form basic degradation products, the acidic degradation products and the basic degradation products buffering at least a portion of the medical implant,

wherein the bioerodible polymer comprises a plurality of fibers comprising the bioerodible polymer metallized with the bioerodible metal.

2. The medical implant of claim 1, wherein the bioerodible metal is selected from the group consisting of magnesium, iron, calcium, and alloys thereof.

3. The medical implant of claim 2, wherein the bioerodible metal comprises magnesium or an alloy thereof.

4. The medical implant of claim 2, wherein the bioerodible metal comprises calcium.

5. The medical implant of claim 1, wherein the bioerodible polymer is selected from the group consisting of polylactic acid, poly(lactic-co-glycolic acid), poly(propylene-ram-c-caprolactone carbonate), polycaprolactone, poly-L-lactic-acid, poly(3-hydroxybutyrate), and a combination thereof.

6. The medical implant of claim 5, wherein the bioerodible polymer is polylactic acid.

7. The medical implant of claim 5, wherein the bioerodible polymer is poly(lactic-co-glycolic) acid.

8. The medical implant of claim 1, further comprising a therapeutic agent.

9. The medical implant of claim 8, wherein the therapeutic agent is incorporated in the bioerodible polymer matrix and elutes as the bioerodible polymer degrades under physiological conditions.

10. The medical implant of claim 8, wherein the therapeutic agent comprises paclitaxel.

11. The medical implant of claim 1, wherein the medical implant consists essentially of the bioerodible portion.

12. The medical implant of claim 1, wherein the medical implant is bioscaffolding, an aneurysm coil, an orthopedic implant, an identification tag, a pacemaking electrode, or a bone screw.

13. The medical implant of claim 1, wherein the medical implant is a stent.