Chemical indicator for oxidation-type sterilization processes using bleachable dyes

• US 5,942,438 A
• Filed: 11/07/1997
• Issued: 08/24/1999
• Est. Priority Date: 11/07/1997
• Status: Expired due to Term

• Current Assignee: Ethicon Incorporated (Johnson & Johnson)
• Original Assignee: Johnson & Johnson Medical Incorporated (Johnson & Johnson)
• Inventors: Hui, Henry K., Feldman, Leslie A., Ebrahim, Alireza, Kohli, Nitu, Antonoplos, Patricia A.
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/966,397
• Time in Patent Office: 655 Days
• Field of Search: 422/57, 422/61, 422/28, 422/34, 422/37, 436/1, 436/2, 436/166
• US Class Current: 436/1
• CPC Class Codes: A61L 2/28 Devices for testing the effectiveness or completeness of sterilisation, e.g. indicators which change colour apparatus involving enzymes or microorganisms C12M1/34; methods involving enzymes or microorganisms C12Q1/00
• CPC Class Codes: C12Q 1/22 Testing for sterility conditions
• CPC Class Codes: G01N 31/226 for investigating the degree of sterilisation

Abstract

A method and apparatus for detecting exposure to an oxidation-type sterilant using a chemical indicator comprising bleachable dye is disclosed. Using the method and apparatus disclosed, a bleachable azo dye is incorporated with an anodized aluminum or chromate conversion coated surface and exposed to an oxidation-type sterilant, such as hydrogen peroxide, and inspected upon completion of the sterilization process for color change. If exposed to sterilant for an appropriate amount of time the bleachable dye changes color thereby indicating adequate sterilization. The surface incorporating bleachable dye may be made to change color after a predetermined number of exposures to a oxidation-type sterilant.

Claims

1. A method for indicating adequate exposure to an oxidative sterilant or disinfectant comprising:

exposing a surface having a metallic azo dye thereon to an oxidative sterilant or disinfectant; and

viewing said bleachable dye for a change in color.

2. The method of claim 1, wherein said exposing a surface comprises exposing a metallic surface to an oxidative sterilant or disinfectant.

3. The method of claim 1, wherein said exposing a surface comprises exposing anodized aluminum.

4. The method of claim 1, wherein said exposing a surface comprises exposing a chromate conversion coating.

5. The method of claim 1, wherein said exposing comprises providing oxidation-type sterilant in gaseous form to a chamber containing medical devices and a surface having a non-pH-sensitive, bleachable dye thereon.

6. The method of claim 1, wherein the step of exposing a non-pH-sensitive, bleachable dye comprises exposing aluminum bordeaux RL dye to an oxidative sterilant or disinfectant.

7. The method of claim 1, wherein the step of exposing the metallic azo dye to a oxidative sterilant or disinfectant comprises exposing bleachable dye to hydrogen peroxide, ozone, chlorine dioxide, and peracetic acid.

8. The method of claim 1, wherein the step of exposing a the metallic azo dye to a oxidative sterilant or disinfectant comprises exposing a bleachable dye to a sterilant in plasma form.

9. The method of claim 1, wherein said exposing comprises using a chemical indicator strip having a metallic azo dye thereon in an oxidative sterilization chamber.

10. The method of claim 1, wherein said exposing comprises placing a test pack with the metallic azo dye chemical indicator thereon in an oxidation-type sterilization chamber, said test pack configured to provide for gas flow into said test pack by diffusion.

11. The method of claim 1, wherein said exposing comprises placing a container in a sterilization chamber, said container having a cover, said cover secured to said container with a tamper-evident device, said tamper-evident device having said surface with the metallic azo dye thereon.

12. The method of claim 1, wherein said change in color is not apparent until a plurality of exposing steps are conducted.

13. The method of claim 1, wherein said exposing a surface comprises exposing a flexible medium having the metallic azo dye and adhesive thereon.

14. The method of claim 1, wherein said exposing comprises placing a self-contained biological indicator having a surface with the metallic azo dye thereon in an oxidative sterilization chamber.

15. The method of claim 14, wherein said surface having the metallic azo dye thereon comprises a generally flat disc on the cap of said self-contained biological indicator.

16. A method for determining if a device has been exposed to an oxidation-type sterilization process a predetermined number of times comprising:

exposing a device with a surface having a metallic azo dye thereon to an oxidation-type sterilant, said dye configured to change color after a predetermined number of oxidation-type sterilization processes;

viewing said surface after said exposing to determine if the color of said dye has changed from the original color of said dye.

17. The method of claim 16, wherein said exposing comprises exposing the surface with the metallic azo dye thereon in contact with an oxidation-type sterilant, said surface with the metallic azo dye thereon residing on an aluminum substrate.

18. The method of claim 16, wherein said exposing comprises exposing a device with an anodized aluminum surface having the dye thereon to a sterilant, said dye configured to change color after a predetermined number of sterilization processes.

19. The method of claim 16, wherein said exposing comprises exposing a device with a chromate conversion coated surface having dye thereon to a sterilant, said dye configured to change color after a predetermined number of sterilization processes.

20. The chemical indicator of claim 16, wherein said surface comprises of polyester, polystyrene, polyethylene, polypropylene, and cellulosics.

21. The method of claim 16, wherein said surface comprises a flexible medium having adhesive on one side.

22. The method of claim 16, wherein said surface comprises part of a tamper-evident device.

23. The method of claim 16, wherein said azo dye is configured to change color after a predetermined number of exposures to an oxidation-type sterilant.

24. The method of claim 23, wherein said predetermined number of exposures comprises the number of times a medical device may be used before the warranty of said medical device expires.

25. An apparatus for determining exposure to an oxidation-type sterilization comprising:

metallic surface means for containing a metallic azo dye thereon;

the metallic azo dye on said surface means for indicating exposure to an oxidation-type sterilant.

26. The apparatus of claim 25, wherein said indicator means is generally pH nonreactive.