Brief Introduction of the Ethylene oxide sterilization

At present, ethylene oxide is widely used for sterilization of medical devices. Ethylene oxide is a broad-spectrum sterilant. It is a flammable and explosive toxic gas with aromatic ether smell. The relative density is 0.884 at 4°C, the boiling point is 10.8°C, and its density is 1.52g. /cm3. At room temperature, it is easy to volatilize into a gas, and when the concentration is too high, it can cause an explosion.

Scope of application

Ethylene oxide does not damage sterilized items and has strong penetrating power, so most items that are not suitable for general methods can be disinfected and sterilized with ethylene oxide. For example, electronic equipment, optical equipment, medical equipment, fur, cotton, chemical fiber, plastic products, endoscopes, dialyzers and disposable medical supplies, etc. Ethylene oxide is currently one of the most important low-temperature sterilization methods.

Advantage

1. It can kill all microorganisms, including spores, Mycobacterium tuberculosis, bacteria, viruses, fungi, etc.

2. Sterilized items can be wrapped and encapsulated as a whole to maintain a sterile state before use.

3. Relatively speaking, ethylene oxide does not corrode plastics, metals, and rubbers, and will not make things yellow or brittle.

4. It can penetrate objects with irregular shapes, complex structures and difficult to permeate (such as long and thin catheters) for sterilization.

5. It can be used to sterilize items that cannot be soaked with disinfectant, dry heat, pressure, steam and other chemical gases.

Instructions

Since ethylene oxide is flammable, explosive, and toxic to humans, it must be carried out in a closed ethylene oxide sterilizer.

Ethylene oxide sterilizer and its application

There are many types of ethylene oxide sterilizers currently in use. Large-scale containers have tens of cubic meters, medium ones have 1-10 cubic meters, and small ones have a few tenths to one cubic meter. They each have different purposes.

Large-scale ethylene oxide sterilizer:

Generally used for the sterilization of a large number of processed items, the dosage is 0.8kg/m³～1.2kg/m³, and the effect is 6h at 55℃～60℃.

Medium-sized ethylene oxide sterilizer:

Generally used for the sterilization of disposable medical supplies. This kind of sterilization equipment is complete and highly automated, and can be used with pure ethylene oxide or a mixed gas of ethylene oxide and carbon dioxide. Generally required sterilization conditions are: concentration, 800 mg/L～1000mg/L; temperature, 55℃～60℃; relative humidity 60%～80%; action time 6 h. Vacuum is required to complete the sterilization. Sterilized items are often sealed and packaged with plastic film permeable to ethylene oxide. If there is a filter membrane that can filter air on the small package, the sterilization effect will be better.

Small ethylene oxide sterilizer:

It is mostly used in the medical and health departments to process a small amount of medical equipment and supplies. At present, there are 100% pure ethylene oxide or a mixture of ethylene oxide and carbon dioxide. This kind of sterilizer has a relatively high degree of automation, can automatically vacuum, automatically add medicine, automatically adjust the temperature and relative humidity, and automatically control the sterilization time.

The requirements for medium and small ethylene oxide sterilizers are: have good pressure resistance and airtight performance, should be able to withstand a hydraulic test of 1.25 times the working pressure, without degeneration and leakage, and can be vacuumed to 53.3 kPa or more; accurate dosage, good heat preservation performance, can adjust the temperature and relative humidity in the sterilizer; after sterilization, when flushing with external ambient air, the input air passes through a high-efficiency filter, which can filter 99.6 particles ≥0.3µm % Or more; after the discharged residual ethylene oxide is harmlessly treated, the residual ethylene oxide in the sterilized articles should be less than 15.2mg/m; the concentration of ethylene oxide in the sterilization environment should be less than 2mg/m.