ETO (Ethylene Oxide) Residue Test

Sterilizing medical devices with ethylene oxide is a common practice due to extensive material compatibility. The main side effect of using ethylene oxide as a sterilizing agent is that it can leave residue on the devices being processed.

In general, the residues that can be found on the device after this process are as follows:

• Ethylene oxide: Residue that may occur after processing is complete
• Ethylene chlorohydrin: Residue formed when ethylene oxide comes into contact with free chloride ions
• Ethylene glycol: Residue formed when ethylene oxide comes into contact with water

These residues can be harmful to both workers and patients. Therefore, it is important that all devices meet the limit values ​​in the AAMI 10993-7 standard. Limits designed by the Association for the Advancement of Medical Devices (AAMI) vary depending on the intended use of the device.

For this reason, devices are divided into three main groups: limited use, long-term use and permanent use. There are also several special device groups with their own limitations. Devices without patient contact are not required to meet this standard.

According to the AAMI 10993-7 standard, no exposure limit has been established for ethylene glycol because it is unlikely that biologically significant residues of ethylene glycol will be present when risk assessment is made.

Surface contact or implantable devices must meet an additional set of criteria called the tolerable contact limit. The purpose of this limit is to prevent local irritation due to the release of ethylene oxide or ethylene chlorohydrin from the device.

In an ethylene oxide process, most residue problems are overcome with a few simple changes to existing sterilization parameters. For new device manufacturers, residue problems are eliminated in advance by considering the following methods when developing sterilization parameters:

• Nitrogen washes
• Added heat
• Extended ventilation
• Load configuration

If residues are a problem or pose a challenge to a new device, sterilization tests must be performed first, and in particular to ensure that the correct test methods are used, in order to minimize the effects of the ethylene oxide sterilization process.

Our organization also provides ETO (ethylene oxide) residue testing services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.