Ethylene Oxide Sterilizers – What You Need To Know

Ethylene Oxide Sterilizers are among the commonly used chemical methods of sterilization. They are often used alongside physical methods such as dry heat and autoclave steam sterilization. Ethylene oxide (EtO) gained popularity as a disinfectant for surgical and pharmaceutical products because it comes across as a very practical option. Working with the same efficiency as hot steam and high pressure, Ethylene Oxide Sterilizers are suitable for heat and moisture sensitive materials.


Ethylene Oxide Sterilizers – Structure and Working


ethylene oxide sterilizersIn its most basic form, the sterilizer is constructed like a container and the items to be sterilized go straight into it. The gas chamber is well-sealed to prevent leaks and human exposure to the alkaline agent. The container is saturated with the toxic gas, ethylene oxide in this case. It infiltrates the object and its packaging and kills all the present microbes. Because of its highly toxic and inflammable nature, it is mixed with inert gases.


The process of sterilization using ethylene oxide is divided into 3 stages:


1. Preconditioning: This is the first stage of ethylene oxide sterilization. It involves preparing the chamber environment and the load by regulating temperature, humidity and pressure settings. During this stage, the air is removed from the chamber. Also, the product is humidified to make the process more effective. The jacket surrounding the sterilizer holds steam which keeps the temperature within the chamber constant.

2. Sterilization: The actual sterilization process begins at this stage. The product is introduced into the chamber and exposed to EtO. It is injected into the chamber via evaporation wherein liquid ethylene oxide is heated to form a gas. The amount of concentration of gas determines the amount of time the procedure will take complete.

3. Aeration: Also known as degassing, this is the final stage. It involves removing residual Ethylene Oxide from the load and the chamber. Many materials absorb the gas and if they come in contact with human skin, it can be harmful. The amount of time required to complete the procedure depends upon the product and materials. The procedure might be completed in the same chamber or the product may be placed in a separate aeration cabinet.

The entire procedure must be conducted under the supervision of skilled technicians and keeping in mind the necessary safety precautions.


Is ethylene oxide a suitable for all types of material?


The use of Ethylene Oxide was first discovered in 1859; however, it gained industrial recognition as a sterilizing agent more than 4 decades later in the early 1900s. The properties of this gas make it a highly suitable option for all those materials that cannot withstand high heat or moisture.

Metals cannot be treated in a steam autoclave sterilizer because they exhibit a tendency to be oxidized. Thus, slight moisture exposure causes metal to disintegrate. Plastics and organic substances on the other hand, can be treated only in an autoclave sterilizer because the dry heat of an oven can cause them to melt and burn.

Gas chemical sterilizers like ethylene oxide make up for this drawback as they can be used to disinfect metal, glass and plastic surfaces in addition to organic substances. It is highly toxic even at low temperatures. Ethylene oxide sterilizers can also be used on devices and equipment that are made up of electronic components.

One of the biggest challenges facing the medical industry today is the need to provide sterile products, those that are completely free of microbial life. With Ethylene Oxide Sterilizers, at hand medical and research centers can find an efficient, cost-effective, practical and time-saving solution when it comes to the sterilization of medical equipment.