Sterilization methods for medical devices

• US 8,747,738 B2
• Filed: 08/14/2007
• Issued: 06/10/2014
• Est. Priority Date: 08/15/2006
• Status: Expired due to Fees

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Freeman, Abigail
• Primary Examiner(s): CLEVELAND, TIMOTHY C
• Application Number:
  US11/893,230
• Publication Number:
  US 20080044553A1
• Time in Patent Office: 2,492 Days
• Field of Search: 422/28, 427/2.24, 623/1.11, 623/1.2, 623/1.42, 623/1.43, 623/1.46
• US Class Current: 422/28
• CPC Class Codes: A61F 2/0095 Packages or dispensers for prostheses or other implants for intraocular lenses A61F2/1691; for dental surgery A61C19/02
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• 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 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61L 2/07 Steam
• CPC Class Codes: A61L 2/08 Radiation
• CPC Class Codes: A61L 2/081 Gamma radiation
• CPC Class Codes: A61L 2/082 X-rays
• CPC Class Codes: A61L 2/085 Infrared radiation
• CPC Class Codes: A61L 2/087 Particle radiation, e.g. electron-beam, alpha or beta radiation
• CPC Class Codes: A61L 2/18 Liquid substances or solutions comprising solids or dissolved gases
• CPC Class Codes: A61L 2/186 Peroxide solutions
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2/22 Phase substances, e.g. smokes, aerosols or sprayed or atomised substances
• CPC Class Codes: A61L 2202/23 Containers, e.g. vials, bottles, syringes, mail
• CPC Class Codes: A61L 2202/24 Medical instruments, e.g. endoscopes, catheters, sharps
• CPC Class Codes: A61L 2420/02 Methods for coating medical devices

Abstract

Methods of sterilizing medical devices, including implantable medical devices like stents, chemically and with radiation are disclosed. Methods of preparing a sterile, packaged medical device, including a sterile, packaged implantable medical device or stent are disclosed.

Claims

1. A method of sterilizing a stent, the method comprising:

exposing the stent to a sterilizing chemical at ambient temperature;

performing one or more processing operations on the exposed stent, wherein the one or more processing operations includes coating the exposed stent that includes applying a coating material to the exposed stent, wherein the coating is performed aseptically to ensure sterility of the stent from the exposure of the stent; and

packaging the processed stent that includes a coating from the coating step, wherein the sterility assurance level (SAL) of the packaged stent is less than a selected value due to the exposure to the sterilizing chemical.

2. The method of claim 1, wherein the stent comprises a biostable or bioabsorbable polymer.

3. The method of claim 1, wherein the one or more processing operations are further selected from the group consisting of heating the coated stent, mounting the stent onto a delivery device, and attaching the mounted stent onto a delivery system.

4. The method of claim 1, further comprising performing one or more processing operations prior to exposing the stent to the sterilizing chemical.

5. The method of claim 1, wherein the sterilizing chemical is a liquid or vapor.

6. The method of claim 5, wherein exposing the stent to a sterilizing chemical comprises immersing the stent in the liquid.

7. The method of claim 1, wherein exposing the stent to a sterilizing chemical comprises spraying the sterilizing chemical on the stent.

8. The method of claim 1, wherein exposing the stent to a sterilizing chemical comprises applying the sterilizing chemical to a surface of the stent with an application instrument.

9. The method of claim 1, wherein the selected value of the sterility assurance level (SAL) is less than or equal to 1×

10<sup>−

6</sup>.

10. The method of claim 1, wherein the selected value of the SAL is less than or equal to 1×

10<sup>−

3</sup>.

11. The method of claim 1, wherein the sterilizing chemical is selected from the group consisting of toluene, formaldehyde, acetone, isopropyl alcohol, and combinations thereof.

12. The method of claim 1, wherein the sterilizing chemical is free of water.

13. The method of claim 1, wherein the one or more processing operations are performed aseptically.

14. The method of claim 13, wherein the exposure to the sterilizing chemical is performed aseptically.

15. The method of claim 1, further comprising exposing the packaged stent to radiation, the radiation exposure being less than 15 KGy.

16. The method of claim 15, wherein the radiation is electron beam radiation.

17. The method of claim 15, wherein the exposure level is between 5 and 15 KGy.

18. The method of claim 17, wherein the radiation is electron beam radiation.

19. The method of claim 1, wherein the sterilizing chemical is toluene.

20. The method of claim 1, wherein the sterilizing chemical is formaldehyde.

21. The method of claim 1, wherein the sterilizing chemical is acetone.

22. The method of claim 1, wherein the sterilizing chemical is isopropyl alcohol.

23. The method of claim 1, wherein ambient temperature is 20°

C. to 27°

C.

24. The method of claim 23, wherein ambient temperature is 20°

C. to 25°

C.

25. The method of claim 23, wherein ambient temperature is 22°

C. to 27°

C.

26. The method of claim 1, wherein the exposure to the sterilizing chemical occurs under conditions of relative humidity of less than about 50%.

27. The method of claim 26, wherein the exposure to the sterilizing chemical occurs under conditions of relative humidity of less than about 30%.

28. The method of claim 27, wherein the exposure to the sterilizing chemical occurs under conditions of relative humidity of less than about 20%.