ETHYLENE OXIDE STERILIZATION VALIDATION

[acejyke]

Good Day.

I would like to ask some questions/guidance with regards to EtO validation.

• During our half cycle we put IPCD and EPCD, but the result was there are BI growths on IPCD as well as EPCD, is this considered as a failed result?
• We repeat the half cycle, this time both IPCD and EPCD are all negative, is this also a failed result?

ISO 11335:2014 9.4.2.5 states that “if the overkill half cycle approach is used then there shall be no positive IPCD from half cycle.
Postive EPCD during half cycle are acceptable if they have demonstrated greater resistance than the IPCD providing a “worst-case challenge” for routine processing. However all IPCD should test negative”

- Based on the above requirement, we have difficulty on judging the results. Is there any other way or a justification that can be used to accept the above result.

Thank you in advance. Hoping you help and guide us.

 

[planB]

Are there any differences between the initial and the repeated half cycle in terms of cycle parameters, used PCD (lot), handling of PCDs before/after exposure, microbiological methods or anything else that might give a hint for the cause of the two different outcomes?

Did you test the PCDs in a test of sterility or have them quantitatively analysed? In case of the latter, what was the spore count for the iPCDs and ePCDs, respectively? What was the test result of your positive control?

 

[acejyke]

Sir/Maam,

None was changed. We also checked the machine for any problem, but it is running well.

With regards to the sterility test, no, our test is just the BI test (BI strip into the broth medium). We also did not performed quantitative analysis, not so familiar with that. Is the quantitative analysis that you refer to is similar to the "Spore recovery count test"? but the sample shall be that of the positive growth?

Sorry for the inexpertise , just a newbie.

Thank you.

 

[planB]

Yes, the quantitative BI analysis delivers a (surviving) spore count. This would provide you the information whether your half cycle may be just at the brink of delivering the required SAL.

How many iPCDs and ePCDs did you actually employ?

Did you also leave the validation load unaltered between the 2 runs?

In case really absolute nothing was changed between the two runs: Could you repeat the half cycle run at least one more time and report the outcome?

 

[chris1price]

Out of interest, have you performed the fractional, sub-lethal cycles? How conclusive were the results?