However, a special knowledge should be applied on those kind of projects, as many factors should be taken into account like safety, product technical specifications, cycle efficiency and economic studies (ROI).

What is the ethylene Oxide?

For those who don't know that gas, the ethylene oxide (EO/ETO) is a colourless and odourless gas, having the following characteristics due to its chemical properties:

• An excellent diffusion and absorption into the porous materials.
• Very efficient at low temperature, ideal to sterilize thermo-sensitive products (mainly plastics).
• A preservation of the material characteristics during and after the sterilization.
   

What are the materials that could be sterilized with the ethylene oxide sterilization process (eo/eto)?

It's thanks to all its characteristics (previously mentioned) that this gas is able to:

• Spread into creases and difficult access to be sterilized.
• Sterilize between 25ºC and 60ºC (low temperature) ensuring neither deformation nor destruction of the sterilized elements.
• Go across wrapping membranes that contain the product.
• It is for all these reasons that ethylene oxide sterilization process is perfect for the sterilization of thermo-sensitive products like: wrapping, plastic products, catheters, raw materials, surgical, medical and optical instrumentation, prosthesis and custom procedure packs….

That process is able to sterilize all the materials that cannot be sterilized by traditional methods, and is especially efficient for to reach hard access areas.

What are the advantages of ethylene oxide sterilization process?

Several advantages for ethylene oxide process:

• It is able to sterilize some products and materials that could not sterilized by traditional sterilization process (steam for example).
• It can also sterilize thermo-sensitive materials without bringing propriety changes on them, many thanks to the fact that only low temperature process is used.
• That's a sterilization process having a high efficiency as antivirus, bactericide and fungicide.
• Its high diffusion coefficient gives the advantage to reach any difficult access area like wrapping, creases, etc.
• This sterilization process doesn't alter physical qualities and esthetical of the product sterilized.
   

Why does the know-how is so important?

The know-how is very important for the safety of this process, as well as for the security of the personal, but is also useful to optimise the sterilization cycles.

Don't forget that the ethylene oxide is a dangerous gas because it's explosive, inflammable, toxic and mutagenic. Therefore, we must use it properly and adopt several precautions.

One of the important points of this process is the ethylene oxide sterilization cycle. For an optimized ethylene oxide sterilization cycle, we must perfectly control the following variables:

• Gas concentration,
• Pressure,
• Humidity,
• Temperature,
• Exposure time

An excellent correlation with those variables is very important to get an expected result.

The Ethylene Oxide sterilization consists of 3 main phases:

1. Conditioning/Pre-conditioning
2. Sterilization
3. Aeration/degassing

More information in our web “EO sterilization process”.

The control of the key parameters until the end of the cycle sterilization will allow to have an optimized process.

Why does a good sterilizer design is so important?

The know-how, as explained previously, is a very important point in the ethylene oxide sterilization process, but we must not minimize the importance of having an appropriate design, that should be taken into consideration for the manufacturing.

The autoclave/sterilizer has to withstand several thousand of cycles during its live, as pressure variations could affect lead to fatigue. Those cycles can cause structure deformations, and that's why the autoclave has to be well calculated during the design phase, built according the rules of the art, using high quality materials, perfect welding procedures,….

In terms of configurations, the manufacturer can offer several options and accessories.

Concerning RSD® and our collaborator Inoxtorres SL, those options can be offered:

• Parametric release,
• Jacket cooling system,
• Automatic loading and unloading system,
• Proportional pneumatic valves,
• ... 

Those auxiliary equipment can be also proposed:

• Preconditioning room,
• Degassing room,
• Pure steam generator,
• Monitoring system: LEL (explosimetric) & PPM (toxicometric) detectors,
• Gas purification system (catalytic or scrubber),
• ...
   

RSD® has a huge experience on the ethylene oxide sterilization sector (design, qualification, installation, training, audit, advisory ...). The collaboration with Inoxtorres SL for the equipment manufacturing & installation gives the possibility to the final user to expect a customized design and especially focused on turnkey projects.

For further information, contact us. Our team of ETO sterilization process experts will be pleased to answer you.