Is Aeration Process in ETO Sterilization Validation Required?

A

ANDY-QA

Dear ALL

Really need your help.

1. Aeration process in ETO sterilization validation it is a must?

2. Can we exclude this aeration process if we can verify by doing ETO residual that our ETO level for product less than 4mg as required by ISO 10993-7?

3. Our ETO chamber having function flushing which is the process purpose likely same as aeration. Can we consider this flushing as aeration?

4. Aeration room or in chamber what is the parameter we need to control to said that this process is validated and can rely on it

TQVM
 
T

thnksnow247

My experience is with sterilization of a single use polymer based product.

You need to validate that after a set period of time ETO levels in your product have dropped to acceptable levels. The reality is that you will need some period of time to get samples to the lab and perform the eto residual testing, this time period would define the minimum aeration time, because you haven't verified ETO levels at an earlier time period. You may also need to used the requirement for maximum ETO surface area concentration from 10993-7.

In summary, you want some defined aeration time, this can be short if you are able to validate it.

ETO aeration rate is influenced by temperature and fresh air flush rates. Elevated temperatures are typically used to increase aeration, though a controlled room temperature may work.
 
A

ANDY-QA

Dear thnksnow247

Thank for the response.

1. Actually for aeration process, we already set it 48H but i can't find any document that mention how this days is choose.

2. From your reply you mean by doing the ETO residual we can actually know the minimum time of aeration, right?

3. ...maximum ETO surface area concentration from 10993-7.- This one you mean the calculation in PPM right for ETO residual?
 

planB

Super Moderator
ANDY-QA,

adding to what thnksnow247 wrote:

1. Aeration process in ETO sterilization validation it is a must?

Aeration is an integral part of the overall sterilization process, which has to be validated. So yes, you have to validate except you want to follow ISO 11135:2014, Annex E.2.4 i) and verify each batch on its own merits. However, this is definitely more tedious than validating EO residuals during an initial sterilisation validation.

2. Can we exclude this aeration process if we can verify by doing ETO residual that our ETO level for product less than 4mg as required by ISO 10993-7?

Yes, you can - in case you have a limited-exposure device without any surface contact. Otherwise, additional EO limits apply. Do not forget to also consider the applicable limits for ECH.

3. Our ETO chamber having function flushing which is the process purpose likely same as aeration. Can we consider this flushing as aeration?

Per ISO 11135:2014, section 3.15, flushing typically refers to the active removal of EO from the sterilisation chamber by applying pressure differentials. But yes, flushing can also be used to aerate the product.

4. Aeration room or in chamber what is the parameter we need to control to said that this process is validated and can rely on it

Refer to ISO 11135:2014, sections 9.5.4.g)&h) and 10.2.n)&o)

3. ...maximum ETO surface area concentration from 10993-7.- This one you mean the calculation in PPM right for ETO residual?

Refer to ISO 10993-7:2008, sections 4.3.5.2 and 4.3.5.3

HTH, Gerhard
 
A

ANDY-QA

TQVM for the reply Gerhard,

Aeration is an integral part of the overall sterilization process, which has to be validated. So yes, you have to validate except you want to follow ISO 11135:2014, Annex E.2.4 i) and verify each batch on its own merits. However, this is definitely more tedious than validating EO residuals during an initial sterilisation validation.
- this annex can't find in the standard "ISO 11135:2014, Annex E.2.4 i" it is right?


Yes, you can - in case you have a limited-exposure device without any surface contact. Otherwise, additional EO limits apply. Do not forget to also consider the applicable limits for ECH.

- yes you mean if we can confirm during sterilization validation the EO or ECH residual are below the limit mean aeration can exclude. Or it reflected to your first answer which if we not validate the aeration process we need to verify each batch on its own merits. One to ask, how many day the aeration process need to be done is base one ETO/ECH residual curve decay right?

Per ISO 11135:2014, section 3.15, flushing typically refers to the active removal of EO from the sterilisation chamber by applying pressure differentials. But yes, flushing can also be used to aerate the product.
- if after flushing ETO/ECH residual immediately can confirm below limit during sterilization validation so no need aeration process?


Refer to ISO 11135:2014, sections 9.5.4.g)&h) and 10.2.n)&o)
- Noted but surprisingly no need to monitor ETO level that aerate out during aeration process to confirm ETO level below 5ppm (standard expose limit below 1 h)


Refer to ISO 10993-7:2008, sections 4.3.5.2 and 4.3.5.3
-Noted TQ

HTH, Gerhard
 

somashekar

Leader
Admin
Keeping the standards aside and looking more into the process, the aeration is a vital process in the ETO cycle.... Why.
Because ethylene oxide (EO) gas is toxic to humans, restrictions have been imposed on its use for sterilization, specifying allowable levels of residual EO remaining in sterilized apparatus and materials.
So what is the material of your device in sterilization ? Does it absorb and leach later like PVC material ?
The aeration time that optimizes the removal of the remaining EO when a rigid sterilizing container is used for a vessel had not been identified.
So aeration process requires validation in ETO cycle.

Some food for thought
 
A

ANDY-QA

Thank Somashekar for the comment

Few series of ETO/ECH residual testing we done, our product was achieve below limit at day 1. So, aeration still required?
 

planB

Super Moderator
ANDY-QA,

in the end you have to demonstrate that your product's residual levels _consistently_ and _reproducibly_ comply to ISO 10993-7 within the (worst-case) tolerances of your process definition. In this respect, I would consider performing "a few series of ETO/ECH residual testing" as exploratory feasibility study, but not a validation per the standard requirements.

Refer also to ISO 11134:2014, section D.6.2.1b), which says
Residues of EO and its reaction products can be hazardous. It is essential for the manufacturer of the product to be sterilized to be aware of the possible occurrence of residues in the product. Temperature, dwell time, forced heated air circulation, load characteristics, product and packaging materials all affect the efficiency of aeration, and the set points and tolerances should be taken into account when evaluating residual levels as outlined in ISO 10993-7. Aeration can be performed within the sterilizer, in a separate area(s), or in a combination of both. [...]. Inadequately aerated items and packaging will release EO, which can injure patients and health care facility personnel.

HTH,

Gerhard
 
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