How To Test Eto Gas Sterilization

Testing and Validation of EtO

1. Process Validation:

   • Biological Indicators (BIs): These are used to challenge the sterilization process. BIs contain a known quantity of highly resistant microorganisms, typically Bacillus atrophaeus or Geobacillus stearothermophilus. The sterilization process is considered effective if these microorganisms are inactivated.
   • Chemical Indicators (CIs): These are used to visually confirm that the sterilization process has occurred. CIs change color when exposed to EtO under specific conditions, providing a quick visual check.

2. Physical Monitoring:

   • Gas Concentration: The concentration of EtO gas in the sterilization chamber is monitored to ensure it remains within the specified range. This is crucial as the effectiveness of sterilization is directly related to the concentration of the gas.
   • Temperature and Humidity: Both parameters are continuously monitored and controlled. The temperature typically ranges from 37°C to 63°C, and relative humidity is maintained between 40% and 80%.

3. Residual Testing:

   • Ethylene Oxide Residuals: After sterilization, it is essential to test for residual EtO on the products. The ISO 10993-7 standard outlines acceptable limits for EtO and its by-products, such as ethylene chlorohydrin (ECH). Products must be tested to ensure these limits are not exceeded, ensuring safety for end-users.

4. Aeration:

   • Degassing: This is a critical phase where the sterilized items are aerated to remove any residual EtO. The duration of aeration can vary but often lasts from several hours to days, depending on the material and the amount of EtO absorbed.

5. Environmental and Safety Monitoring:

   • Leak Detection: Regular checks for leaks in the sterilization equipment and ventilation systems are necessary to prevent EtO exposure to workers and the environment.
   • Air Monitoring: Continuous monitoring of EtO levels in the workplace is essential to ensure they remain below occupational exposure limits.

Regulatory Compliance

Compliance

Challenges and Considerations

• Material Compatibility: Not all materials are compatible with EtO sterilization. It is crucial to assess the compatibility of materials with EtO to prevent damage or degradation.

• Cycle Optimization: The sterilization cycle must be optimized to balance effectiveness with safety. This involves adjusting parameters like gas concentration and exposure time to achieve the desired sterility assurance level.

• Safety Concerns: Due to its toxic nature, handling EtO requires stringent safety measures. Facilities must be equipped with appropriate ventilation and safety protocols to protect workers.

Conclusion

Testing and validating EtO gas sterilization is a complex but essential process in the production