ANTIMICROBIAL MATERIAL AND METHOD FOR MAKING THE SAME

• US 20090186064A1
• Filed: 12/31/2008
• Published: 07/23/2009
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: Michael Szycher
• Original Assignee: Michael Szycher
• Inventors: Szycher, Michael
• Granted Patent: US 7,998,498 B2
• Time in Patent Office: Days
• US Class Current: 424/423
• CPC Class Codes: A61K 31/28 Compounds containing heavy metals
• CPC Class Codes: A61K 33/38 Silver; Compounds thereof
• CPC Class Codes: A61L 2300/104 Silver, e.g. silver sulfadiazine
• CPC Class Codes: A61L 2300/404 Biocides, antimicrobial agents, antiseptic agents
• CPC Class Codes: A61L 29/049 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61P 31/04 Antibacterial agents
• CPC Class Codes: C08L 31/04 Homopolymers or copolymers of vinyl acetate
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

This invention provides a modified catheter biomaterial that provides both immediate, and long-term microbiocidal effects on otherwise antibiotic-resistant strains of microorganisms. The material, which exhibits good mechanical performance characteristics for medical devices, is composed of a hydrophobic polyurethane (PU), a hydrophilic polyethylene vinyl acetate (PEVA), a soluble silver salt and a sparsely-soluble silver salt. The hydrophobic polyurethane provides the good physical properties, the PEVA the hydrophilicity necessary to allow some water ingress into the catheter, the soluble silver salt for an immediate burst effect, and the sparsely-soluble silver salt for sustained-release over many months postimplantation.

Claims

1. An antimicrobial material comprising an intimate mixture of:

a hydrophobic polyurethane (PU);

a hydrophilic polyethylene vinyl acetate (PEVA); and

a water soluble ionic silver salt.

2. The antimicrobial material as set forth in claim 1 further comprising a sparsely-soluble ionic silver salt in an intimate quaternary mixture.

3. The antimicrobial material as set forth in claim 2 wherein the sparsely soluble ionic silver salt comprises silver iodate.

4. The antimicrobial material as set forth in claim 2 wherein the PEVA is between 2% and 20% by weight of the material.

5. The antimicrobial material as set forth in claim 4 wherein the soluble ionic silver salt is between 1 and 10% by weight of the material.

6. The antimicrobial material as set forth in claim 4 wherein the sparsely soluble ionic silver salt is between 1 and 15% by weight of the material.

7. The antimicrobial material as set forth in claim 2 wherein the soluble ionic silver salt is at least one of silver trifluoro acetate and silver nitrate.

8. The antimicrobial material as set forth in claim 2 wherein the soluble ionic silver salt is silver trifluoro acetate and the sparsely soluble ionic silver salt is silver stearate.

9. The antimicrobial material as set forth in claim 2 wherein the soluble ionic silver salt is silver trifluoro acetate and the sparsely soluble ionic silver salt is silver iodate.

10. The antimicrobial material as set forth in claim 2 wherein the soluble ionic silver is silver trifluoro acetate and the sparsely soluble ionic silver salt is silver citrate.

11. The antimicrobial material as set forth in claim 2 wherein the sparsely soluble ionic silver salt is silver stearate.

12. The antimicrobial material as set forth in claim 2 wherein the sparsely soluble ionic silver compound is non-discoloring silver iodate.

13. The antimicrobial material as set forth in claim 2 wherein the sparsely soluble ionic silver salt is silver citrate.

14. A medical device having a wall constructed and arranged to contact internal tissue and fluids of a patient, the wall including the antimicrobial material as set forth in claim 2.

15. The medical device as set forth in claim 14 wherein the wall includes (a) a first portion having a first composition and (b) a second portion having a second composition.

16. The medical device as set forth in claim 15 wherein the first portion includes at least one of the soluble ionic silver salt in a first concentration and the sparsely soluble ionic silver salt in a first concentration and (b) a second portion having at least one of the soluble ionic silver salt in a second concentration, different from the first concentration and the sparsely soluble ionic silver salt in a second concentration, different from the first concentration.

17. The medical device as set forth in claim 16 wherein the wall defines an indwelling catheter shaft and each of the first portion and the second portion define concentric layers of the catheter shaft.

18. The medical device as set forth in claim 15 wherein the wall defines a wall of an indwelling catheter.

19. The medical device as set forth in claim 18 wherein the indwelling catheter comprises a Chronic Dialysis Catheter.

20. The medical device as set forth in claim 18 wherein the indwelling catheter comprises a Peripherally Inserted Central Catheter.

21. The medical device as set forth in claim 18 wherein the indwelling catheter comprises a Urinary Catheter.

22. The medical device as set forth in claim 18 wherein the indwelling catheter comprises a Gastrostomy Catheter.

23. A method for producing an antimicrobial material comprising the steps of:

(a) providing polyurethane (PU) to a solvent solution;

(b) providing polyethylene vinyl acetate (PEVA) to the solvent solution in a predetermined amount;

(c) providing a soluble ionic silver compound to the solvent solution in a predetermined amount; and

(d) forming a predetermined shape with the solution of steps (a), (b) and (c) and removing the solvent.

24. The method as set forth in claim 23 further comprising, before step (d), (c)(i)providing a sparsely soluble ionic silver compound to the solvent solution in a predetermined amount.

25. The method as set forth in claim 24 wherein step (d) includes mixing each of the PU, PEVA, soluble ionic silver compound and sparsely soluble ionic silver compound in and directing the mixture through a die of a twin-screw extruder.