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Post Validation Changes in Breathable Area

Q.

We are considering changing one of our current packages to one that would double the surface area of porous substrate. We currently use EtO cycles that we do not plan to modify. Does an established rationale exist or is one possible that allows for the change without a full revalidation?

A.

Pouches, vented bags and other gas-sterilizable packages require an assessment of the ability of the sterilant gas to penetrate the package and interact with the medical device. Different sterilization cycles can be expected for each package size and type and a change from one to another may require a reassessment of the sterilization cycle.

The repeated entrance and evacuation of gas during the sterilization cycle necessitates an
evaluation of the ability of the gas to infiltrate all areas of the package. Although the area of porous material present is a primary variable that impacts the total flowrate into and out of a vented package, other variables must be considered. Blockage of the vent by secondary packaging or adjacent packages can occur and should be prevented in order to
maximize the flowrate of sterilant gas. A change in the location of the breathable web on a package may also necessitate reconsideration of the sterilization cycle.

During the cycle, the sterilant gas must remain in the package for a sufficient time to kill any microbes present. Its residence time in the package can be estimated by the ratio of the volume of the package to the total flowrate of gas through the breathable web. Any changes in the area of the breathable web or the package size, type or configuration will effect the residence time and therefore the efficiency of the sterilization cycle.

To the best of our knowledge, there is no established rationale that allows changes in the
breathable web or package to be made without a sufficient reassessment of its effects on the sterilization process. If the above considerations are made, a rationale may bepossible that allows the change without a full revalidation. During our discussions, an EtO contract sterilizer advised that a small-scale verification could aid in supporting the rationale and minimizing risk. It is still, however, the responsibility of the medical device manufacturer to evaluate if the change will continue to guarantee the safety and efficacy of the device.

Last updated on 2007-05-30 10:51:33 UTC
Keywords: sterilization, breathable area, revalidation, porous, porosity, EtO, sterilize

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