Sterilizing hydrophilic contact lenses

• US 4,312,833 A
• Filed: 09/16/1977
• Issued: 01/26/1982
• Est. Priority Date: 11/14/1974
• Status: Expired due to Term

• Current Assignee: Chauvin Pharmaceuticals Limited Bampton Road Harold Hill Romford
• Original Assignee: Smith and Nephew Pharmaceuticals Ltd (Smith & Nephew PLC)
• Inventors: Ruder, Gary C. F., Clough, David, Drain, David J.
• Primary Examiner(s): Garris, Bradley
• Application Number:
  US05/833,729
• Time in Patent Office: 1,593 Days
• Field of Search: 21/58, 21/57, 21/DIG. 3, 21/DIG. 4, 252/187 R, 252/188.3 R, 424/14, 422/30, 422/37
• US Class Current: 422/30
• CPC Class Codes: A61L 12/105 Iodine, iodides or iodophores

Abstract

A sterilizing solution for contact lenses particularly those formed of a hydrophilic polymer comprises (a) an alkali metal salt of formic acid, and (b) an iodophor selected from the group consisting of complexes of iodine with hydrophilic polymer and non-ionic surface active agent. The alkali metal salt and the iodophor are present in predetermined quantities such that the sterilizing solution contains sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20° to 25° C. The iodophor and the alkali metal salt of formic acid may be packaged in solid or powdered form, particularly in unit doses, and made into solution at the point of use.

Claims

1. A method of sterilizing a contact lens formed of a hydrophilic polymer which comprises contacting the lens with an aqueous solution of an iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents, said solution containing a sufficient quantity of an alkali metal salt of formic acid to reduce the available iodine level of the solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.;

the reaction products of the iodophor and the alkali metal salt being non-toxic and a non-irritant.

2. A method as claimed in claim 1 in which the iodophor is a polyvinylpyrrolidone/iodine complex.

3. A method as claimed in claim 1 in which the solution contains sufficient alkali metal salt of formic acid to reduce the available iodine level of the solution to substantially zero within a period of from 1 to 4 hours at a temperature of from 20°

to 25°

C.

4. A method as claimed in claim 1 in which the sterilizing solution contains sufficient iodophor to give an initial available iodine concentration of at least 20 ppm.

5. A method as claimed in claim 4 in which the sterilizing solution contains sufficient iodophor to give an initial available iodine concentration of from 20 to 300 ppm.

6. A method as claimed in claim 5 in which the sterilizing solution contains sufficient iodophor to give an initial available iodine level of from 25 to 100 ppm.

7. A method as claimed in claim 1 in which the alkali metal salt is sodium formate.

8. A method as claimed in claim 1 in which the alkali metal salt of formic acid is present in an amount of from 10 to 800 moles per mole of iodine in the iodophor.

9. A method as claimed in claim 8 in which the alkali metal salt is present in an amount of from 100 to 400 moles per mole of iodine in the iodophor.

10. A method as claimed in claim 1 in which the solution also contains a buffering agent to give the solution a final pH of from 5 to 8.

11. A method as claimed in claim 10 in which the solution contains a buffering agent in an amount sufficient to give the solution a final pH of from 7 to 7.5.

12. A method as claimed in claim 1 in which the solution also contains a tonicity adjusting agent.

13. A two-part pack for the production of a sterilizing solution for treating a contact lens formed of a hydrophilic polymer comprising (a) an aqueous solution of an alkali metal salt of formic acid, and (b) a solid iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents;

the aqueous solution being such that when the solid iodophor is added to a predetermined quantity of the aqueous solution, the resulting sterilizing solution contains sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.;

the reaction products of the iodophor and the alkali metal salt being non-toxic and a non-irritant.

14. A two-part pack as claimed in claim 13 in which the aqueous solution of alkali metal salt is contained in a sterilized package containing said predetermined quantity of reducing agent solution.

15. A two-part pack as claimed in claim 13 in which the quantity of aqueous solution of alkali metal salt contained in said container is more than said predetermined quantity of aqueous solution and the aqueous solution also contains an antibacterial preservative agent.

16. A two-part pack as claimed in claim 13 in which the solid iodophor also contains sodium chloride to render the final sterilizing solution isotonic.

17. A two-part pack as claimed in claim 13 in which the solid iodophor comprises from 2 to 30 mg of the iodophor.

18. A two-part pack as claimed in claim 17 in which the solid iodophor also contains sodium chloride.

19. A two-part pack for the production of a sterilizing solution for treating a contact lens formed of a hydrophilic polymer comprising (a) an aqueous solution of an iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents and (b) a solid alkali metal salt of formic acid;

the solid alkali metal salt and iodophor solution being such that when the solid alkali metal salt is added to a predetermined quantity of the iodophor solution, the resulting sterilizing solution contains sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.;

the reaction products of the iodophor and the alkali metal salt being non-toxic and a non-irritant.

20. A two-part pack as claimed in claim 19 in which the solid alkali metal salt also contains a buffering agent in an amount sufficient to give the final sterilizing solution a pH of from 5 to 8.

21. A two-part pack as claimed in claim 19 in which the solid alkali metal salt also contains sodium chloride to render the final sterilizing solution isotonic.

22. A two-part pack as claimed in claim 19 in which the solid alkali metal salt is present in a quantity of from 20 to 300 mg.

23. A two-part pack as claimed in claim 22 in which the solid alkali metal salt also contains a buffering agent.

24. A two-part pack as claimed in claim 22 in which the solid alkali metal salt also contains sodium chloride.

25. A two-part pack for the production of a sterilizing solution for treating a contact lens formed of a hydrophilic polymer comprising (a) an aqueous solution of an alkali metal salt of formic acid, and (b) an aqueous solution of an iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents;

the iodophor and alkali metal salt solutions being such that when a predetermined quantity of the iodophor solution is added to a predetermined quantity of the alkali metal salt solution, the resulting sterilizing solution contains sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.;

the reaction products of the iodophor and the alkali metal salt being non-toxic and a non-irritant.

26. A two-part pack as claimed in claim 25, in which the alkali metal salt solution is contained in a sterilized package containing said predetermined quantity of alkali metal salt solution.

27. A two-part pack as claimed in claim 25 in which the quantity of alkali metal salt solution contained in said container is more than said predetermined quantity of alkali metal salt solution and the alkali metal salt solution also contains an antibacterial preservative agent.

28. A two-part pack as claimed in claim 25, in which one or both of the alkali metal salt and iodophor solutions contain sodium chloride to render the final sterilizing solution isotonic.

29. A two-part pack as claimed in claim 25 in which one or both of the alkali metal salt and iodophor solutions contains a buffering agent.

30. A solid dosage unit form for the production of a sterilizing solution for treating a contact lens formed of a hydrophilic polymer comprising (a) a solid iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents and (b) a solid alkali metal salt of formic acid, the iodophor and alkali metal salt being such that on dissolution in a predetermined quantity of water to form a sterilizing solution the resulting sterilizing solution contains a sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.

31. A solid dosage unit form as claimed in claim 30 containing from 2 to 30 mg of iodophor and from 20 to 300 mg of alkali metal salt.

32. A solid dosage unit form as claimed in claim 30 also containing sufficient sodium chloride to render the sterilizing solution isotonic.

33. A solid dosage unit form as claimed in claim 30 also containing sufficient of a buffer to give the sterilizing solution a pH of from 5.0 to 8.0.

34. A two-part pack for the production of a sterilizing solution for treating a contact lens formed of a hydrophilic polymer comprising (i) a solid dosage unit form comprising (a) a solid iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents and (b) a solid alkali metal salt of formic acid and (ii) water;

the iodophor and alkali metal salt being such that on dissolution in a predetermined quantity of water to form a sterilizing solution the resulting sterilizing solution contains sufficient alkali metal salt to reduce the available iodine level of the sterilizing solution to substantially zero within a period of from 30 minutes to 8 hours at a temperature of from 20°

to 25°

C.

35. A two-part pack as claimed in claim 34 in which the water is contained in a sterilized package containing said predetermined quantity of water.

36. A two-part pack as claimed in claim 34 in which the quantity of water contained in said container is greater than the said predetermined quantity and the water also contains an antibacterial preservative agent.

37. A method of sterilizing a contact lens formed of a hydrophilic polymer which comprises contacting the lens with an aqueous solution of an iodophor selected from the group consisting of complexes of iodine with hydrophilic polymers and nonionic surface active agents containing sufficient iodophor to give an initial available iodine concentration of at least 20 ppm, said solution containing an alkali metal salt of formic acid in an amount of from 10 to 800 moles per mole of available iodine in the iodophor.

38. A method as claimed in claim 37 in which the iodophor is a polyvinylpyrrolidone/iodine complex.

39. A method as claimed in claim 37 in which the sterilizing solution contains sufficient iodophor to give an initial available iodine concentration of from 20 to 300 ppm.

40. A method as claimed in claim 39 in which the sterilizing solution contains sufficient iodophor to give an initial available iodine level of from 25 to 100 ppm.

41. A method as claimed in claim 37 in which the alkali metal salt is sodium formate.

42. A method as claimed in claim 37 in which the alkali metal salt is present in an amount of from 100 to 400 moles per mole of iodine in the iodophor.

43. A method as claimed in claim 37 in which the solution also contains a buffering agent to give the solution a final pH of from 5 to 8.

44. A method as claimed in claim 37 in which the solution contains a buffering agent in an amount sufficient to give the solution a final pH of from 7 to 7.5.

45. A method as claimed in claim 37 in which the solution also contains a tonicity adjusting agent.