Process and apparatus for dry sterilization of medical devices and materials

• US 4,818,488 A
• Filed: 07/14/1987
• Issued: 04/04/1989
• Est. Priority Date: 02/25/1987
• Status: Expired due to Fees

• Current Assignee: Adir Jacob
• Original Assignee: Adir Jacob
• Inventors: Jacob, Adir
• Primary Examiner(s): Richman, Barry S.
• Assistant Examiner(s): Alexander, Lyle A.
• Application Number:
  US07/072,899
• Time in Patent Office: 630 Days
• Field of Search: 422/22, 422/23, 422/21
• US Class Current: 422/23
• CPC Class Codes: A61L 2/14 Plasma, i.e. ionised gases

Abstract

A process for dry sterilization of medical devices and materials in which these materials are subjected to an electrical discharge in a gaseous atmosphere to produce an active plasma to produce an electrically active neutral species for surface sterilization of the devices and materials.

Claims

1. A method for sterilization of medical devices and material comprising the steps of,

placing said devices and materials within a metallic perforated electrode, generally cylindrical in shape, said electrode being positioned within, and generally concentric with, a gas-tight confining chamber, said chamber being generally cylindrical, formed from metal and connected to a point of potential reference,

evacuating said chamber to a substantially low pressure and introducing a gas consisting of argon, or helium, or a mixture thereof, into said chamber,

initiating an electrical discharge in said gas within said chamber by application of RF voltage between said internal perforated electrode and the metal chamber wall, creating a gas plasma, having a substantially field free and glowless volume within the perforated electrode containing said devices and materials, whereby said devices and materials are contacted by substantially electrically neutral active species at a temperature below that which would be detrimental to said devices and materials,

maintaining said gas plasma for a controlled period of time,

maintaining a flow of said gas through said chamber during said electrical discharge;

and

evacuating the gas plasma residual gases from said chamber prior to withdrawing said devices and material from it.

7. A method in accordance with any one of claims 1, 2, 3, 4, or 5 wherein said gas is substantially pure argon.

8. A method in accordance with any one of claims 1, 2, 3, 4, or 5 wherein said gas is substantially pure helium.

9. A method in accordance with any one of claims 1, 2, 3, 4, or 5 wherein said gas is a gaseous mixture of 50% helium and 50% argon.

2. A method for sterilization of medical devices and materials enclosed within sealed pouches formed of gas permeable materials comprising the steps of:

placing said pouches containing said material or devices to be sterilized within a metallic perforated electrode generally cylindrical in shape, said electrode positioned within, and generally concentric with a gas-tight confining chamber, said chamber being generally cylindrical, formed from metal and connected to a point of potential reference,

evacuating said chamber to a substantially low pressure and introducing a gas consisting of argon, or helium, or a mixture thereof, into said chamber,

initiating an electrical discharge in said gas within said chamber by application of RF voltage between said internal perforated electrode and the metal chamber wall creating a gas plasma, and

having a substantially field free and glowless volume within the perforated electrode containing said pouches, said pouches containing said material devices and materials, whereby said devices and materials are contacted by substantially electrically neutral active species at a temperature below that which would be detrimental to said devices and materials, and maintaining said gas plasma for a controlled period of time,

maintaining a flow of said gas through said chamber during said electrical discharge; and

evacuating the gas plasma residual gases from said chamber prior to withdrawing said sealed pouches from it.

3. A method for sterilizing medical devices and materials enclosed within pouches formed of gas permeable materials comprising the steps of,

placing said pouches containing said devices and materials within a first metallic perforated electrode generally cylindrical in shape, said electrode being positioned within and generally concentric with a gas-tight confining chamber, said gas-tight chamber being metallic and generally cylindrical, said gas-tight chamber and said first perforated electrode being connected to a point of potential reference, said chamber enclosing a second perforated metallic electrode positioned between and generally concentric with said gas-tight chamber and said first perforated electrode,

evacuating said chamber to a substantially low pressure and introducing a gas consisting of argon, or helium, or a mixture thereof, into said chamber,

initiating an electrical discharge in said gas within said chamber by application of RF voltage between said second perforated electrode and said point of potential reference creating a gas plasma having a substantially field free and glowless volume within said first perforated electrode containing said devices and materials, whereby said devices and materials are contacted by substantially electrically neutral active species at a temperature below that which would be detrimental to said devices and materials,

maintaining said gas plasma for a controlled period of time,

maintaining a flow of said gas through said chamber during said electrical discharge;

and

evacuating the gas plasma residual gases from said chamber prior to withdrawing said pouches from it.

4. A method for sterilization of medical devices and materials comprising the steps of,

placing said devices and materials on a metallic electrode, said electrode being positioned within a gas-tight confining chamber being made of metal and connected to a point of potential reference, the internal surface area of said chamber being substantially larger than the surface area of said electrode,

evacuating said chamber to a substantially low pressure and introducing a gas consisting of argon, or helium, or a mixture thereof, into said chamber,

initiating an electrical discharge in said gas within said chamber by application of RF voltage between said metallic electrode and the metal chamber wall creating a gas plasma,

further including a perforated metallic enclosure within said chamber, and electrically insulated from it, said enclosure also being insulated from, and surrounding and containing said metallic electrode and said devices and materials positioned thereon, whereby said devices and materials are contacted by substantially electrically neutral active species at a temperature below that which would be detrimental to said devices and materials,

applying an RF voltage of one frequency to said perforated enclosure and a different frequency to said metallic electrode,

maintaining said gas plasma for a controlled period of time,

maintaining a flow of said gas through said chamber during said electrical discharge;

and

evacuating the gas plasma residual gases from said chamber prior to withdrawing said devices and materials from it.

6. A method in accordance with either one of the claims 4 or 5, wherein said medical devices and materials are enclosed within pouches of gas permable material when said devices and materials are placed within said chamber and remain so until said devices and materials are withdrawn from said chamber.

5. A method for sterilization of medical devices and materials comprising the steps of,

placing said devices and materials on a metallic electrode, said electrode being position within a gas-tight confining chamber, said chamber being made of metal and connected to a point of potential reference, the internal surface area of said chamber being substantially larger than the surface area of said electrode,

evacuating said chamber to a substantially low pressure and a gas consisting of argon, or helium, or a mixture thereof, into said chamber,

initiating an electrical discharge in said gas within said chamber by application of RF voltage between said metallic electrode and the metal chamber wall creating a gas plasma,

further including a perforated metallic enclosure within said chamber, said enclosure being insulated from, but surrounding and containing said metallic electrode and said devices and materials positioned thereon, said enclosure being connected to said point of potential reference, whereby said devices and materials are contacted by substantially electrically neutral active species at a temperature below that which would be detrimental to said devices and materials,

maintaining said gas plasma for controlled period of time,

maintaining a flow of said gas through said chamber during said electrical discharge;

and

evacuating the gas plasma residual gases from said chamber prior to withdrawing said devices and materials from it.