Electrospun Skin Capable Of Controlling Drug Release Rates And Method

• US 20070087027A1
• Filed: 11/10/2006
• Published: 04/19/2007
• Est. Priority Date: 04/11/2002
• Status: Abandoned Application

• Current Assignee: Rob Kiefer, Skott Greenhalgh
• Original Assignee: Rob Kiefer, Skott Greenhalgh
• Inventors: Greenhalgh, Skott, Kiefer, Rob
• Application Number:
  US11/558,845
• Publication Number:
  US 20070087027A1
• Time in Patent Office: Days
• US Class Current: 424/423
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: D01D 5/0038 the fibre formed by solvent evaporation, i.e. dry electro-spinning
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• CPC Class Codes: D01F 1/10 Other agents for modifying properties
• CPC Class Codes: Y10T 442/159 Including a nonwoven fabric which is not a scrim
• CPC Class Codes: Y10T 442/2525 Coating or impregnation functions biologically [e.g., insect repellent, antiseptic, insecticide, bactericide, etc.]
• CPC Class Codes: Y10T 442/3065 Including strand which is of specific structural definition
• CPC Class Codes: Y10T 442/3472 Woven fabric including an additional woven fabric layer
• CPC Class Codes: Y10T 442/614 Strand or fiber material specified as having microdimensions [i.e., microfiber]
• CPC Class Codes: Y10T 442/696 Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, etc.]

Abstract

A versatile covering process enabled through the identification and manipulation of a plurality of variables present in the electrospinning method of the present invention. By manipulating and controlling various identified variables, it is possible to use electrospinning to predictably produce thin materials having desirable characteristics. The fibers created by the electrospinning process have diameters averaging less than 100 micrometers. Proper manipulation of the identified variables ensures that these fibers are still wet upon contacting a target surface, thereby adhering with each other to form a cloth-like material and, if desired, adhering to the target surface to form a covering thereon. The extremely small size of these fibers, and the resulting interstices therebetween, provides an effective vehicle for drug and radiation delivery, and forms an effective membrane for use in fuel cells.

Claims

1. A method of controlling the drug release rate of an implantable drug-containing object comprising covering the object with a fibrous fabric having interstices defined between the fibers that are small enough to control the rate at which a drug contained by the object may elute into tissue surrounding the object when the object is implanted.

2. The method of claim 1 wherein covering the object with a fibrous fabric having interstices defined between the fibers that are small enough to control the rate at which a drug contained by the object may elute into tissue surrounding the object when the object is implanted comprises covering the object with a polymer fabric having a plurality of fibrils having diameters that average less than 100 micrometers.

3. The method of claim 1 wherein covering the object with a fibrous fabric having interstices defined between the fibers that are small enough to control the rate at which a drug contained by the object may elute into tissue surrounding the object when the object is implanted comprises covering the object with a polymer fabric having a plurality of fibrils that are intertangled with each other but not woven.

4. A drug-eluting cloth comprising:

an inner layer of fibers of a first average diameter and defining interstices between the fibers;

a therapeutic releasably contained by the inner layer;

an outer layer of fibers of a second average diameter and defining interstices between said fibers that are smaller than the interstices of the inner layer such that the release rate of the therapeutic is controlled by the interstices of the outer layer;

wherein the outer layer is operably attached to and substantially encasing the inner layer.

5. The drug-eluting cloth of claim 4 wherein the fibers of the outer layer comprise electrospun fibrils having an average diameter of less than 100 micrometers.

6. The drug-eluting cloth of claim 4 wherein the fibers of the inner and outer layers comprise electrospun fibrils.

7. The drug-eluting cloth of claim 6 wherein the first average diameter is greater than the second average diameter.

8. A drug eluding cloth of claim 4 wherein the outer layer comprises a first polymer and the inner layer comprises a second polymer different than the first polymer.

9. The drug-eluting cloth of claim 4 wherein the therapeutic releasably contained by the inner layer is disposed in at least a portion of the interstices of the inner layer.

10. The drug-eluting cloth of claim 4 wherein the therapeutic releasably contained by the inner layer is encased in a plurality of microspheres, which are disposed in at least a portion of the interstices of the inner layer.