Ferromagnetic particles and methods

• US 7,976,823 B2
• Filed: 08/27/2004
• Issued: 07/12/2011
• Est. Priority Date: 08/29/2003
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: McKenna, Erin P., Casey, Thomas V. II, Lanphere, Janel L.
• Primary Examiner(s): Hartley; Michael G
• Assistant Examiner(s): PERREIRA, MELISSA JEAN
• Application Number:
  US10/928,452
• Publication Number:
  US 20050129775A1
• Time in Patent Office: 2,510 Days
• Field of Search: 424/9.32, 424/9.322, 424/9.323, 424/489, 424/646, 424/1.11
• US Class Current: 424/1.11
• CPC Class Codes: A61K 41/0028 Disruption, e.g. by heat or ultrasounds, sonophysical or sonochemical activation, e.g. thermosensitive or heat-sensitive liposomes, disruption of calculi with a medicinal preparation and ultrasounds
• CPC Class Codes: A61K 41/0052 Thermotherapy; Hyperthermia; Magnetic induction; Induction heating therapy
• CPC Class Codes: A61K 9/0009 involving or responsive to electricity, magnetism or acoustic waves; Galenical aspects of sonophoresis, iontophoresis, electroporation or electroosmosis microelectromechanical systems A61K9/0097
• CPC Class Codes: A61K 9/1635 obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• CPC Class Codes: A61K 9/1652 Polysaccharides, e.g. alginate, cellulose derivatives; Cyclodextrin homeopathic globules A61K9/1623
• CPC Class Codes: A61K 9/5026 obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• CPC Class Codes: A61K 9/5036 Polysaccharides, e.g. gums, alginate; Cyclodextrin
• CPC Class Codes: A61K 9/5094 Microcapsules containing magnetic carrier material, e.g. ferrite for drug targeting

Abstract

Ferromagnetic particles and methods are disclosed.

Claims

1. A particle having a particle radius (r) extending from a particle center in at least one direction, the particle comprising:

a polymeric matrix; and

a ferromagnetic material contained within the polymeric matrix,

wherein;

the particle has an interior region extending from the particle center to a radius of about r/3 with pores having a mean size of about 20 microns or more,

the particle has a surface region enclosing the interior region with pores having a mean size of about one micron or less,

the particle further comprises a third region between the interior region and the surface region, and

the third region extends to a radius of about 2 r/3 and has pores having a mean size of about 18 microns or less.

2. The particle of claim 1, wherein a density of the ferromagnetic material in the interior region of the particle is greater than a density of the ferromagnetic material at the surface region of the particle.

3. The particle of claim 2, wherein there is substantially no ferromagnetic material at the surface region.

4. The particle of claim 1, wherein the particle further comprises a therapeutic agent contained within the polymeric matrix.

5. The particle of claim 1, further comprising a coating surrounding the polymeric matrix, the coating comprising a therapeutic agent.

6. The particle of claim 1, wherein the polymeric matrix comprises at least one polymer selected from the group consisting of polyvinyl alcohols, polyacrylic acids, polymethacrylic acids, poly vinyl sulfonates, carboxymethyl celluloses, hydroxyethyl celluloses, substituted celluloses, polyacrylamides, polyethylene glycols, polyamides, polyureas, polyurethanes, polyesters, polyethers, polystyrenes, polysaccharides, polylactic acids, polyethylenes, polymethylmethacrylates, polycaprolactones, polyglycolic acids, and poly(lactic-co-glycolic) acids.

7. The particle of claim 1, wherein the ferromagnetic material is selected from the group consisting of transition metals, metal alloys, and metal oxides.

8. The particle of claim 1, wherein the ferromagnetic material is a particle, and the dimension is less than about 40 microns.

9. The particle of claim 1, wherein the ferromagnetic material is a fiber and has a ratio of a largest linear dimension to a smallest dimension of at least about 2:

1.

10. The particle of claim 1, wherein the ferromagnetic material is a fiber has a ratio of a largest linear dimension to a smallest dimension of at most about 20:

1.

11. The particle of claim 1, wherein the ferromagnetic material comprises a combination of fibers having two or more different aspect ratios.

12. The particle of claim 1, wherein the ferromagnetic material is about 0.1 percent by weight to about 90 percent by weight of the particle.

13. The particle of claim 1, wherein the ferromagnetic material is homogeneously distributed in the interior region of the particle.

14. The particle of claim 1, wherein the ferromagnetic material is in a form selected from the group consisting of particle, fiber, and powder.

15. The particle of claim 14, wherein the ferromagnetic material is in the form of a particle having a dimension of more than 15 microns, and the dimension is selected from the group consisting of a width, a diameter, and a length.

16. The particle of claim 1, wherein the polymeric matrix comprises cross-linked polyvinyl alcohol.