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Ethylene Oxide Sterilization

Ethylene Oxide (EO) is a simple chemical compound that is commonly used for gaseous sterilization of disposable healthcare products. A wide variety of materials and components commonly used in the manufacture of these products may be sterilized with ethylene oxide in their final breathable packaging configuration.

History of ethylene oxide

  • 1859 – Ethylene oxide is discovered
  • 1920s/1930s – EO is used for fumigation
  • 1940s – EO is developed as a sterilant by the U.S. military
  • Late 1950s – The McDonald process is patented for medical devices
  • 1998 – EOExpress® technology introduced

How does ethylene oxide work?

Ethylene oxide sterilization is a chemical process consisting of four primary variables: gas concentration, humidity, temperature and time. Ethylene oxide is an alkylating agent that disrupts the DNA of microorganisms, which prevents them from reproducing. Ethylene oxide sterilization assures that a safe and sterile product will be delivered to the market each and every time.

What is ethylene oxide used for?

The EO process is ideal for:
  • Custom procedure kits
  • Cellulose and plastic products that may exhibit discoloration with irradiation
  • Devices manufactured from materials whose physical properties degrade with heat or irradiation
  • Various materials not compatible with other methods of sterilization, such as tissue and collagen

What is a typical ethylene oxide processing cycle?

The EO sterilization process may take place within a traditional cycle or through our exclusive EOExpress® expedited processing cycle. Both options consist of three processing phases:

  • Pre-conditioning: Used to preheat and humidify product loads to predefined conditions. This will assure a repeatable sterilization process regardless of pre-processing load storage conditions
  • Sterilization: Performed using process phases specifically designed to provide the required level of ethylene oxide exposure to assure sterility for a device or family of devices
  • Aeration: Used to accelerate out gassing of exposed product loads and to contain and eliminate residual ethylene oxide emissions

Traditional EO Processing

  • Biological indicators are placed into the sterilization load, and the load is placed into a preconditioning room
  • The product is then moved into the sterilization chamber where it is treated with EO gas
  • Following exposure, the product is transferred into an aeration cell for dissipation of the EO
  • Biological indicators are removed from the product and tested
  • Product is shipped to the Customer while still in quarantine
  • Product is released once the biological indicators have completed testing and the EO residual levels are acceptable

EOExpress® Expedited Processing

  • Product is loaded into the sterilization chamber, where it is exposed to all three phases of the sterilization process (pre-conditioning, sterilization and aeration)
  • This process uses parametric release, which eliminates the labor and time of post-process sterility testing
  • In-chamber aeration prevents products from having to be held for EO residual dissipation
  • Products can be processed and released to market within one day