A Conceptual Framework for the Qualification/Validation of Ethylene Oxide Sterilization Cycles

Abstract

Recent FDA inspections of ethylene oxide sterilization facilities have revealed that many medical products labeled as sterile are processed without a properly validated sterilization cycle. Since there is no clear definition as to what ethylene oxide sterilization qualification/validation entails, this study is an attempt to clarify the meanings of these terms. The difficulty in arriving at the “maximum/minimum” conditions in an ethylene oxide sterilizer is examined. A comparison is made to the use of the Stumbo equation as a measurement of the sterilization effectiveness delivered to the product. The 3-dimensional Cartesian co-ordinate is introduced as a means of defining the loading pattern and the location with the “minimum” conditions for the placement of innoculated products and/or biological indicators. Graphical presentation of the trajectories of the key process parameters is used to illustrate the importance of validation studies prior to making production runs.