METHODS FOR FORMING STABILIZED METAL SALT PARTICLES

• US 20090092538A1
• Filed: 10/08/2007
• Published: 04/09/2009
• Est. Priority Date: 10/08/2007
• Status: Abandoned Application

• Current Assignee: Johnson & Johnson Vision Care Incorporated (Johnson & Johnson)
• Original Assignee: Johnson & Johnson Vision Care Incorporated (Johnson & Johnson)
• Inventors: Khanolkar, Amit, Yewey, Gerald L., Kindt-Larsen, Ture, Sorensen, Jens-Erik
• Application Number:
  US11/868,914
• Publication Number:
  US 20090092538A1
• Time in Patent Office: Days
• US Class Current: 423/491
• CPC Class Codes: A01N 59/16 Heavy metals; Compounds thereof
• CPC Class Codes: A61L 12/088 Heavy metals
• CPC Class Codes: C01G 9/006 Compounds containing, besides zinc, two ore more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C01P 2006/82 water content
• CPC Class Codes: G02B 1/043 Contact lenses

Abstract

The present invention relates to a process for forming stabilized metal salt particles.

Claims

1. A process comprising

a. forming a first solution comprising at least one salt precursor;

b. forming a second solution comprising a complex formed from at least one metal agent and at least one dispersing agent in a particle size stabilizing effective amount;

c. adding said second solution to said first solution at a rate sufficient to maintain a clear solution throughout addition and to form a product solution comprising stabilized metal salt particles having a mean particle size of less than about 200 nm;

d. drying said product solution to form an antimicrobial metal salt powder comprising 0.01 to about 10 weight % metal in the antimicrobial metal salt powder.

2. The process of claim 1 wherein said second solution has a metal agent concentration of at least about 1500 ppm.

3. The process of claim 1 wherein the dispersing agent is present in said second solution in a concentration between about 20 and about 50 w/w %.

4. The process of claim 1 wherein said first solution has a salt precursor concentration of at least about 1500 ppm.

5. The process of claim 1 wherein said first solution has a salt precursor concentration of at least about 5000 ppm.

6. The process of claim 1 wherein said first solution has a salt precursor concentration of about 5000 ppm to about 50,000 ppm.

7. The process of claim 1 wherein said mean particle size is less than about 100 nm.

8. The process of claim 1 wherein said mean particle size is less than about 50 nm.

9. The process of claim 1 wherein said first and second solutions are aqueous solutions.

10. The process of claim 1 wherein said product solution has a viscosity of less than about 50 cps.

11. The process of claim 1 wherein said first solution is stirred as said second solution is added.

12. The process of claim 9 wherein said solutions are maintained at a pressure between about ambient and about 40 mbar during said adding step.

13. The process of claim 1 wherein said dispersing agents are independently selected from the group consisting of hydroxyalkylmethylcellulose polymers, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, starch, pectin, polyacrylamide, gelatin, polyacrylic acid, organoalkoxysilanes 3-aminopropyltriethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, vinyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane, boric acid ester of glycerin and mixtures thereof.

14. The process of claim 1 wherein at least one of said first and second solution comprises at least one solvent and said powder comprises less than about 10 wt % of said solvent.

15. The process of claim 14 wherein said powder comprises less than about 5% of said solvent.

16. The process of claim 14 wherein said solvent comprises water.

17. The process of claim 14 wherein said metal agent comprises at least one silver salt which is soluble in said at least one solvent.

18. The process of claim 13 wherein said dispersing agent comprises polyvinyl pyrrolidone.

19. The process of claim 18 wherein said polyvinyl pyrrolidone and metal agent are present in said second solution in a molar ratio of at least about 1.5.

20. The process of claim 1 wherein said metal salt has a K_sp of less than about 2×

10<sup>−

10</sup> in pure water at 25°

C.

21. The process of claim 1 wherein said metal salt has a K_sp of not more than about 2.0×

10<sup>−

17</sup> moles/L.

22. The process of claim 1 wherein said second solution has a metal agent concentration of at least about 5000 ppm.

23. The process of claim 1 wherein said first solution has a metal agent concentration of about 5000 ppm to about 50,000 ppm.

24. A process comprising

a. forming a first solution comprising NaI;

b. forming a second solution comprising a complex formed from AgNO₃ and polyvinyl pyrrolidone in a particle size stabilizing effective amount;

c. adding said second solution to said first solution at a rate sufficient to maintain a clear solution throughout addition and to form a product solution comprising stabilized AgI particles having a mean particle size of less than about 200 nm;

d. drying said product solution to form an antimicrobial AgI powder comprising 0.01 to about 10 weight % Ag in the antimicrobial AgI powder.