Sterilization Steps Of Ethylene Oxide Sterilization

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Publish Time: 2024-01-05 | Technical Guide: EO Low-Temperature Sterilization

Ethylene Oxide Sterilization: Scope, Advantages & Steps

Ethylene Oxide (EO) sterilization is recognized globally as the primary low-temperature sterilization method. Its exceptional penetration and non-corrosive nature make it essential for medical devices that cannot withstand heat or moisture.

Scope of Application

Ideal for electronic instruments, optical devices, endoscopes, catheters, plastics, leather, and complex disposable diagnostic supplies.

Key Advantages

Kills all microorganisms (including spores); penetrates irregular structures; preserves material properties (no yellowing/brittleness); allows for pre-sealed packaging.

[Image: Comparison of various medical items suitable for EO sterilization vs. those that are not]

Industrial Sterilizer Comparison

Sterilizer Type Typical Volume Primary Use Cases Core Parameters
Large Scale 50 – 100 m³ Mass industrial production 0.8-1.2 kg/m³ dosage; 55-60°C; 6h cycle
Medium Scale 6 – 50 m³ Single-use medical factory lines Pure EO or CO2 mixture; 60%-80% Humidity
Small Scale 1 – 5 m³ Hospitals & Health departments High automation; integrated air filtration

The 6 Core Steps of the EO Sterilization Process

A validated EO sterilization cycle must follow a precise sequence to ensure both lethality and safety:

Preheating: Chamber and load reach operational temperature.
Vacuuming & Pre-wetting: Air removal followed by humidity injection (60%-80% RH).
Gas Injection: EO gas is introduced to the predetermined concentration.
Exposure Time: Maintaining parameters for a fixed duration (typically 6h).
Purging/Vacuum Pulses: Removing gaseous EO from the chamber.
Aeration: Controlled release of residual EO from items and packaging.
[Image: Diagram of an EO sterilization cycle showing Temperature, Pressure, and Humidity curves]

Critical Success Factors

  • Humidity Control: Relative humidity must be maintained at 60%-80%. Insufficient moisture hinders alkylation, while excessive moisture creates barriers.
  • Load Management: Total load should not exceed 80% of cabinet volume to allow for effective gas diffusion.
  • Packaging Material: Use paper, non-woven fabric, or composite films. Avoid PVC or non-permeable polypropylene.
  • Residual Management: Ventilation must meet environmental regulations, ensuring EO residuals are <2mg/m³ for patient safety.

Choose BOCON for High-Efficiency EO Sterilization

BOCON’s BCS Series ETO Sterilizers are engineered to automate these complex steps with high precision. Our systems feature integrated high-efficiency filters (99.6% at 0.3μm) and advanced vacuum performance (down to 533 kPa) to ensure ISO 11135 compliance and maximum production safety.

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