Ethylene oxide is one of the most commonly used sterilization methods in the healthcare industry because of its non-damaging effects for delicate instruments and devices that require sterilization, and for its wide range of material compatibility. It is used for instruments that cannot tolerate heat, moisture or abrasive chemicals, such as electronics, optical equipment, paper, rubber and plastics.
Ethylene oxide treatment is generally carried out between 30 and 60 °C (86 and 140 °F) with relative humidity above 30% and a gas concentration between 200 and 800 mg/l. Typically, the process lasts for several hours. It is highly effective, as it penetrates all porous materials, and it can penetrate through some plastic materials and films.
Ethylene oxide kills all known microorganisms, such as bacteria (including spores), viruses, and fungi (including yeasts and moulds), and is compatible with almost all materials even when repeatedly applied.
The most common EO processing method is the vaccum assisted gas chamber method. To benefit from economies of scale, EO has traditionally been delivered by filling a large chamber with a combination of gaseous EO either as pure EO, or with other gas like carbon dioxide. The process includes pre conditioning phase, exposure & last is the aeration to remove the EO residue.
To get the optimum sterilization assurance level (SAL) the most important parameters that need to be control are :
For ethylene oxide sterilization, two voluntary consensus standards (ANSI AAMI ISO 11135:2014 and ANSI AAMI ISO 10993-7:2008(R)2012) describe how to develop, validate, and control ethylene oxide sterilization processes for medical devices and the acceptable levels of residual ethylene oxide and ethylene chlorohydrin left on a device after it has undergone ethylene oxide sterilization. These standards help ensure levels of ethylene oxide on medical devices are within safe limits since long-term and occupational exposure