Ethylene Oxide (ETO) Sterilization Process for Medical & Pharmaceutical Products
Ethylene Oxide (ETO) sterilization is mainly used to sterilize medical and pharmaceutical products that cannot support conventional high temperature steam sterilization – such as devices that incorporate electronic components, plastic packaging or plastic containers. ETO gas infiltrates packages as well as products themselves to kill micro organisms that are left during production or packaging processes. This gas, mixed with air at a ratio of at least 3% ETO gas, forms an explosive mixture. Pure ETO gas boiling point is 10.73 ºC at atmospheric pressure. Most of the time, it is mixed with Nitrogen or CO2.
Ethylene Oxide (ETO) sterilization Process
Most ETO sterilization lines involve three different stages. These can be separated into three different cells depending on the size or amount of devices to treat:- Pre Conditioning
- Sterilizer
- Degasser
Pre Conditioning Stage
First, products need to go through a pre conditioning phase to make micro organisms grow. The batch load goes through a dwell time under a controlled environment of : Temperature/HumiditySterilizer Stage
Then the load goes through a long and complex sterilization cycle. Requirements of such a system are :- Accurate temperature control.
- Availability of the control system.
- Accurate pressure and vacuum control.
- Easy displays of process phases
- Dedicated customer recipes.
- Auto batching release through tolerance tests.
- Reporting
- Security interlocks between actuators.
- Alarming.
- Shut down strategies.
- Audit Trail facilities – Trending.
- 21CFR Part11
Once the cycle is started, easy to use displays are required to show
- The actual phase of sterilization
- All the key set points and tolerances as loaded by the recipe
- All the key process values for the auto batch release facility
- Cycle start delay to enable the system to start in stable conditions
- General cell temperature check
- Initial vacuum phase
- Leak rate test
- First flush
- Second flush
- DEC (Dynamic Environmental Conditioning)
- ETO gas injection
- Sterilization dwell time period under ETO Sterilizer
- Post dwell vacuum level
- First wash
- Second wash
- Final air admission
- Final chamber re-evacuation delay
Batch logged files could be searched by the following
- Batch ID
- Customer name
- Recipe
- Product type
- Start and stop time
Degasser Stage
Finally, products need to go through a degassing phase to remove any particle of ETO. The batch load goes over a dwell time under a temperature controlled environmentEthylene Oxide (ETO) Sterilization Process FAQs
1. What is an ETO sterilizer?
An ETO sterilizer, also known as ethylene oxide sterilization, is a type of sterilization equipment that uses the gas ethylene oxide to sterilize medical and other equipment.2. How does an ETO sterilizer work?
An ETO sterilizer works by introducing ethylene oxide gas into a sealed chamber along with the equipment to be sterilized. The gas penetrates the equipment and kills any microorganisms present. The chamber is then evacuated and the equipment is removed.3. What types of equipment can be sterilized using an ETO sterilizer?
An ETO sterilizer can be used to sterilize a wide variety of equipment including medical instruments, lab equipment, and electronic devices. It can also be used to sterilize heat-sensitive materials such as plastics and rubber.4. How to ensure the effectiveness of ETO sterilization?
- Adequate exposure time and concentration of ETO gas should be used.
- Proper loading and placement of the items in the sterilizer chamber is important.
- Proper aeration of the chamber after sterilization is important to remove residual ETO gas.
- Regular maintenance and calibration of the sterilizer equipment is important.
- Regular monitoring and validation of the sterilization process should be done.