Medical device with sponge coating for controlled drug release

• US 6,364,856 B1
• Filed: 04/14/1998
• Issued: 04/02/2002
• Est. Priority Date: 04/14/1998
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Corporation
• Inventors: Andrus, W. Scott, Ding, Ni
• Primary Examiner(s): Nguyen, Anhtuan T.
• Assistant Examiner(s): Thompson, Michael M
• Application Number:
  US09/060,071
• Time in Patent Office: 1,449 Days
• Field of Search: 623/1, 623/11, 623/12, 604/96, 604/264, 604/99, 604/101, 604/104-109, 604/174, 604/265, 604/266, 604/280, 604/282, 604/284, 604/285-287, 604/509, 604/103.02, 427/2.1, 427/2.12, 427/2.13, 427/2.22, 427/2.24, 427/2.25, 427/2.3
• US Class Current: 604/103.02
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61L 2300/236 Glycosaminoglycans, e.g. heparin, hyaluronic acid, chondroitin
• CPC Class Codes: A61L 2300/42 Anti-thrombotic agents, anticoagulants, anti-platelet agents
• CPC Class Codes: A61L 2300/606 Coatings
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: A61M 2025/105 having a balloon suitable for drug delivery, e.g. by using holes for delivery, drug coating or membranes
• CPC Class Codes: A61M 2025/1075 having a balloon composed of several layers, e.g. by coating or embedding
• CPC Class Codes: A61M 2025/1081 having sheaths or the like for covering the balloon but not forming a permanent part of the balloon, e.g. retractable, dissolvable or tearable sheaths
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

The medical devices of the invention comprise an expandable portion which is covered with a sponge coating for release of at least one biologically active material. The sponge coating is made of a non-hydrogel polymer having a plurality of voids. The device can further include means for infusing or expelling the biologically active material or drug into the voids. The drug is delivered to the body lumen of a patient by expelling the drug and inflating or expanding the expandable portion of the catheter or device.

Claims

1. A medical device having at least an expandable portion which is insertable or implantable into a body lumen of a patient,

wherein at least a part of the expandable portion is covered with a sponge coating to form an exposed outermost surface for release of at least one biologically active material, and

wherein the sponge coating comprises a non-hydrogel polymer having a plurality of voids, wherein the voids contain at least one biologically active material and wherein the void space of the sponge coating is greater than about 60% of the volume of the sponge coating.

2. The medical device of claim 1 wherein the voids are formed by eluting a particulate material from the polymer.

3. The medical device of claim 1 further comprising means for infusing the biologically active material into the voids.

4. The device of claim 1 wherein the device is a catheter for delivering the biologically active material and wherein the expandable portion is expandable in response to expansion pressure to substantially fill the cross-section of the lumen and engage the tissue of the lumen.

5. The device of claim 4 wherein the expandable portion is inflated by an inflation lumen connected to a balloon having pores.

6. The device of claim 5 wherein the balloon is capable of containing the biologically active material which can be released through the pores and infused into the voids.

7. The device of claim 4 wherein the expandable portion further comprises a perfusion lumen for sustained infusion of the biologically active material into the voids and inflation of the expandable portion.

8. The device of claim 4 which further comprises control means for synchronizing the deflation of the expandable portion and the infusion of the biologically active material into the voids.

9. The device of claim 1 wherein the polymer comprises an elastomer.

10. The device of claim 9 wherein the elastomer is selected from the group consisting of silicones, polyurethanes, thermoplastic elastomers, ethylene vinyl acetate copolymers, polyolefin elastomers, polyisobutylene and its copolymers and EPDM rubbers.

11. The device of claim 4 wherein the biologically active material is heparin.

12. The device of claim 4 wherein the catheter is capable of delivering a stent for implantation in the body lumen.

13. A method of delivering a biologically active material to a desired location of a body lumen of a patient comprising

a) forming a sponge coating on a surface of an expandable portion of a medical device for insertion or implantation into the body of a patient, wherein the device comprises means for expelling the biologically active material from the device, and wherein the expandable portion has a surface which is adapted for exposure to body tissue of the patient, by

i) applying a composition comprising a non-hydrogel polymer and a particulate material to the surface and

ii) exposing the surface to a solvent to elute the particulate material from the polymer to form a plurality of voids therein,

b) loading the sponge coating with the biologically active material, by expelling the biologically active material from the device and

c) inflating the expandable portion at the desired location to deliver the drug.

14. The method of claim 13 which further comprises deflating the expandable portion and simultaneously expelling the biologically active material into the voids.

15. The method of claim 13 wherein the particulate material is eluted in vivo while the device is inserted or implanted in the body to form a plurality of voids in the sponge coating, and wherein the void space of the sponge coating is greater than about 60% of the volume of the sponge coating.

16. The method of claim 15 wherein the particulate material is a biologically active material.

17. A stent prosthesis having at least an expandable portion which is insertable or implantable into a body lumen of a patient,

wherein at least a part of the expandable portion is covered with a sponge coating to form an exposed outermost surface for release of at least one biologically active material, and

wherein the sponge coating comprises a non-hydrogel polymer having a plurality of voids, wherein the voids contain at least one biologically active material, and wherein the void space of the sponge coating is greater than about 60% of the sponge coating.

18. The stent of claim 17 wherein the stent is a self-expanding stent.

19. The stent of claim 17 wherein the stent is a balloon-expanding stent.

20. The stent of claim 17 wherein the voids are formed by eluting a particulate material from the polymer.

21. The stent of claim 17 wherein the voids are formed while the stent is inserted or implanted in the body lumen.

22. The stent of claim 17 wherein the polymer comprises an elastomer.

23. The device of claim 22 wherein the elastomer is selected from the group consisting of silicones, polyurethanes, thermoplastic elastomers, ethylene vinyl acetate copolymers, polyolefin elastomers, and EPDM rubbers.

24. The device of claim 17 wherein the biologically active material is heparin.