Study of sterilizing effectivity of different ethylene oxide gaseous mixtures using CFCs and HCFCs (Oxyfume 12R and 2002R).

The use of ethylene oxide as a sterilizing agent has been frequently practiced, especially taking into account the huge variety of medical devices produced with heat sensitive materials. Mixtures of ethylene oxide and inert gases have been widely adopted in order to decrease the undesirable flammable and explosive properties of ethylene oxide. This article provides a study regarding the sterilizing effectiveness of two ethylene oxide blends: Oxyfume 2002R (using HCFCs 22 and 124) and Oxyfume 12R (using CFC 12), at different temperatures (45, 55, and 65 degrees C). To accomplish this procedure, sub-lethal challenges were performed (0, 3, 6, 9, 12, and 15 minutes) using biological indicators (obtained in the laboratory) made of Bacillus subtilis var. niger ATCC 9372. The sterilizing efficacy of both mixtures was equivalent at the gas concentration of 600 mg/L. The influence of higher temperatures was thus proved.