Gaseous sterilant

For gaseous sterilization procedures, elevated temperatures are monitored for each sterilization cycle by temperature probes, and routine leak tests are performed to ensure gas-tight seals. Pressure and humidity measurements are recorded. Gas concentration is measured independently of pressure rise, often by reference to weight of gas used. 

Gaseous sterilization Ethylene oxide (EO) Reactive chemical Indicator paper impregnated with a reactive chemical which undergoes a distinct colour change on reaction with EO in the presence of heat and moisture. With some devices rate of colour development varies with temperature and EO concentration Gas concentration, temperature, time (selected devices) NB a minimum relative humidity (rh) is required for device to function... 

Sintin-Damao, K. Other gaseous sterilization methods. In Morrissey, R., Phillips, G.B. (eds.). Sterilization Technology A Practical Guide for Manufacturers and Users of Health Care Products. New York Van Nostrand Reinhold, 1993. 

Ernst, R.R. Shull, J.J. Ethylene oxide gaseous sterilization. I. Concentration and temperature effects. Appl. Microbiol. 1962, 10, 337-341. 

Biological indicators (Bis) for use in thermal, chemical or radiation sterilization processes consist of standardized bacterial spore preparations which are usually in the form either of suspensions in water or culture medium or of spores dried on paper, aluminium or plastic carriers. As with chemical indicators, they are usually placed in dummy packs located at strategic sites in the sterilizer. Alternatively, for gaseous sterilization these may also be placed within a tubular helix (Line-Pickerill) device. After the sterilization process, the aqueous... 

Ernst, R. R. (1973). Ethylene oxide gaseous sterilization for industrial applications. In Industrial Sterilization (G. Briggs Phillips and W. S. Miller, eds.). Durham, N.C. Duke University Press. 

Sterilization can be achieved by moist or dry heat, by ethylene oxide (or other suitable gaseous sterilizing agent), by filtration with subsequent aseptic filling of sterile final containers, or by irradiation with ionizing radiation (but not with ultraviolet radiation unless the process is thoroughly validated). Each method has its particular applications and limitations. Where possible and practicable, heat sterilization is the method of choice. 

STERILISATION (1) A process intended to produce sterile goods. (2) Reduction of the probability of the presence of viable micro-organisms to an acceptable extent. Sterilisation is effected by moist or dry heat by treatment with a gaseous sterilant such as ethylene oxide, by irradiation with ionising radiation or, where such processes are inapplicable to solutions, by filtration. 

Ethylene oxide is used for the gaseous sterilization of disposable medical instruments. When the 2 -deoxyguanosine groups of a microorganism s DNA react with ethylene oxide, they are alkylated (see page 514), and the microorganism can no longer reproduce. 

---