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Nitrogen Dioxide Sterilization Technology

Noxilizer has developed a room temperature nitrogen dioxide sterilization and decontamination technology that addresses many of the challenges associated with traditional methods of sterilization.

Only NO2 technology offers all the following benefits:

  • Effective, room temperature sterilization and decontamination process
  • Sterilization with or without vacuum, with humidification or limited humidification
  • Faster processing time (no preconditioning)
  • Maintenance of material properties for heat-sensitive products
  • Flexible cycles for materials compatibility
  • Safe and simple alternative to use in-house

NO2 is Rapid and Effective

NO2 is effective against a wide range of microorganisms. The primary mechanism of lethality is the degradation of DNA. Late outgrowth studies have shown no repair mechanisms for the DNA degradation.

White Paper: "Overview of Nitrogen Dioxide Sterilization Process," June 2012.

Data just-released demonstrates the effectiveness of NO2 as a sterilant with a reduction in endotoxins on temperature-sensitive prefilled, polymer syringes.

Technical Update: "Depyrogenation and Sterilization of Medical Device Materials with Nitrogen Dioxide Gas," October 2013.

Testing has also been completed to demonstrate the decontamination and depyrogenation of a Weiler Engineering ASEP-TECH® BFS System with NO2. The results indicate this process offers: enhanced decontamination and depyrogenation capability with the increased safety of an automated process with no human intervention in the filling zone that can be easily validated.

Technical Update: Decontamination and Depyrogenation of an ASEP-TECH® BFS System.

NO2 Penetrates Complex Geometries

The boiling point of NO2 is relatively low, at 21°C, and Noxilizer employs sterilant concentrations that are well below the vapor pressure of NO2. The NO2 gas will not condense on devices, or as it travels down long lumens or into other complex geometries. Therefore, NO2 gas can sterilize medical devices with complex geometries. The video above demonstrates sterilization in a long lumen.

White Paper: "NO2 vs H2O2 Lumen Testing Summary," August 2012.

Aerates Rapidly – Minutes vs. Days

Low boiling point, coupled with the low NO2 sterilant concentrations, translates into rapid aeration of the sterilization chamber and exposed products.
NO2 does not permeate materials to the same degree as other methods, greatly reducing the overall cycle time of the sterilization process and eliminating the lengthy post-sterilization aeration. This benefit applies to terminal sterilization using a batch process or high level decontamination in isolators.

Typical Vacuum Process Profile
Typical Non-Vacuum Process Profile

Leaves Low Residue Levels – Non-carcinogenic, non-cytotoxic and non-teratogenic

The rapid aeration process results in fewer residues on product and packaging. Noxilizer’s sterilant residues are non-carcinogenic, non-cytotoxic and non-teratogenic. Sterilized packages may be handled immediately after the cycle.

Flexible to Design Custom Cycles – Optimize Materials Compatibility and Sterilization

Process Parameter Range
NO2 Gas Concentration From 1 mg/L to 20 mg/L
Exposure Time Varies with application
Door-to-door Time 1 to 2 Hours (for humidified cycle)
Relative Humidity 0% to 90%
Depth of Vacuum 7 to 760 Torr
Chamber Temperature 18°C - 30°C

Key advantages over all other sterilization methods:

  • Ambient cycle for vacuum-sensitive products
  • Operates even at very low humidity for moisture-sensitive materials

Compatible with Common Packaging

Noxilizer’s sterilization process is compatible with commonly used sterile barrier packaging. This includes: non-woven polypropylene, Tyvek® pouches, Tyvek®-Mylar® pouches and plastic tubs with Tyvek® lids. Noxilizer’s process is not compatible with cellulosic materials such as paper and cardboard.

Compatible with Medical Device Materials

NO2 is less oxidative than traditional oxidizing sterilants like hydrogen peroxide and peracetic acid.  Noxilizer has tested many medical device materials including metals, polymers, bioresorbables and adhesives.  Compatible materials showed no increase in cytotoxic response.  The true room temperature performance of the Noxilizer process allows temperature sensitive materials to be processed.

Compatible Materials
Stainless Steel Polyethylene Polyetherimide Thermoplastic Elastomers
Aluminum Polypropylene Polycarbonate
Gold (Plating) PET/PETG Cyclic Olefins Polylactides Bioresorbables
Glass/Ceramic Polystyrene PVC*
Fluoropolymers Polysulfones Silicone* This list is not exhaustive
Viton (Gaskets) PEEK/PAEK Hypalon
Incompatible Materials Design Alternatives
Delrin® (polyacetal) Polyetherimide, polysulfone, PEEK
Nylon® Polyester or polyolefins
Polyurethane Thermoplastic elastomers (TPE)
Cellulosics (some paper) Polystyrene or polyester label stock
Nitinol Depends upon application

Delrin®, Mylar®, Nylon® and Tyvek® are registered trademarks of E. I. du Pont de Nemours and Company or its affiliates.

Scrubber Technology – Removes NO2 from Exhaust

No special ventilation required.  Noxilizer sterilization units can be fitted with a scrubber to remove NO2 from the exhaust gases.  The result is a solid, landfill-safe material that can be discarded without hazardous materials limitations.

Biological Indicator

The most resistant organism to the NO2 sterilization process is Geobacillus stearothermophilus; the same BI used in steam and hydrogen peroxide sterilization processes.

Chemical Indicator

Noxilizer offers color change chemical indicators with a proprietary ink to show when product has been exposed to NO2.  The indicating ink can be printed on labels and packages.

NO2 Sterilization-Video

"Low Temperature Sterilization: Discussion of Current Methods including Nitrogen Dioxide" June 2013. Presentation by David Opie PhD.

To learn more about the Noxilizer RTS 360 Industrial NO2 Sterilizer, contact Mike Valentine at mvalentine@noxilizer.com.