Adding an extra Label on an Ethylene Oxide Sterilized Box


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I have a device that is packed in a cardboard box and then sterilized via EtO. The sterilization process has been validated. Does adding an extra label to the outside of the box before the device gets sterilized mean a new validation study to ensure the EtO is not absorbed by the new label? i.e. does the addition of a new label affect permeability of the EtO gas through the box?
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Hi dr1vn,

I would recommend reading through AAMI TIR28:2009(R)2013 Product Adoption and Process Equivalence for Ethylene Oxide Sterilization. Annex A contains a list of questions which we took and made into a type of product adoption form and use it to determine if further evaluations are required with a candidate product or to document the rationale for adopting the candidate product into the cycle.

In general, the answer to your question is, maybe...Adding a label could effect the transfer of heat, moisture, or gas. This would depend on the size of the label, the material permeability, etc. Assuming that you are using a contract sterilizer, they should be able to walk you through the process and even provide services for product adoption studies ($$$).

Assuming you are using the overkill EtO method, I would recommend performing a reduced microbial study. Otherwise, you will need a solid rationale to justify your reasons that the addition of the label does not compromise the effectiveness of the sterilization cycle.


Super Moderator

concurring with bjohnsonrli:

You have to evaluate whether the additional label implies that your product constitutes a greater challenge to the sterilization cycle than you validated product in terms of

- cycle lethality: can you demonstrate with existing data that your product with label does not create a more tortuous pathway for the sterilant gas (and humidity) to achieve the required SAL? Does your PCD (process challenge device) cover your product with label?
-> "Is it harder for the gas to get in?"

- residual levels: can you demonstrate with existing data that your product with label does not have a negative impact on the aeration properties of your product and thus negatively affect your validated residuals levels? Would you have another worst-case product for residuals that still covers your product with attached label?
-> "Is it harder for the gas to get out?"

As bjohnsonrli popinted out, AAMI TIR28, question list in annex A helps you through this evaluation process. In case of any "yes" answer, consider to perform (limited) experimental re-validation work.




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Thanks Gerhard and bjohnsonrli,

I checked the standard and I feel like I should be answering "yes" as a label on a cardboard box would impede gas going in and out... that is if the gas permeates through the cardboard to get into the device packaged within. If the gas goes around the corners and folds to reach the device then perhaps a label on the outside is okay.

Since permeability is an unknown, then I think a study is in order to at least put some numbers behind our ultimate labelling decision
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