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Noxilizer’s Sterilization Technology

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

Noxilizer has developed a room temperature surface sterilization process based on nitrogen dioxide, NO2. This patented sterilization technology has applications in multiple market segments: medical device manufacturing, pharmaceutical and biotechnology isolators, clinical hospital reprocessing and sterilization for the developing world.

Sterilization with NO2 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.

For more information, please see attached White Paper entitled, "Mechanism Overview," June 2012.

NO2 Sterilization and Endotoxin Reduction

Data just-released demonstrates the effectiveness of NO2 as a sterilant with a reduction in endotoxins on temperature-sensitive prefilled, polymer syringes. For more information, please see attached Technical Update entitled, "Depyrogenation and Sterilization of Medical Device Materials with Nitrogen Dioxide Gas," October 2013.

Penetration into 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.

For more information please see attached White Paper entitled, "NO2 vs H2O2 Lumen Testing Summary," August 2012.

Rapid Aeration – Minutes vs. Days

Rapid Aeration ? Minutes vs. Days
Click to Image to enlarge view

The relatively low boiling point of NO2, coupled with the low concentrations employed during sterilization, translates into rapid aeration of the sterilization chamber and exposed products. NO2 does not permeate materials to the same degree as ethylene oxide (EO). This greatly reduces the overall cycle time of the sterilization process and eliminates the need for lengthy post-sterilization aeration as compared to EO. This benefit applies to terminal sterilization using a batch process or high level decontamination in isolators.

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.

Flexibility 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

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.

Packaging – Compatible with Many Options

Noxilizer’s sterilization process is compatible with sterile barrier packaging already on the market.  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.  Sterilization is performed prior to final packaging.

Materials Compatibility – Many 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.  Each device will be evaluated individually. 

Incompatible materials and design alternatives

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.

To learn more about Noxilizer’s room-temperature based sterilization solution contact Mike Valentine at