Irradiation Sterilization Validation Maximum Dose - VDmax 25 method (ISO 11137)

F

Frodeno

Due to some project team issues I have had to take over a project to validate a sterilization process for a class IIb product. All of the dose verification activities have been completed and as I read the standard the information seems to be in good shape (the VDmax 25 method was used). However, I am a bit confused about the requirement from the standard (ISO 11137) for maximum dose establishment . Will an auditor expect so see complete product performance data including packaging repeated at the max dose ? it seems that this would be required according to the standard. Also, does this mean that shelf life would have to be repeated after max dose irradiation ? In some respects this ssems to be more of a design verification activity than process validation. Although there is a lot of information out there on establishment of the minimum dose there appears to be very little regardind the maximum dose. So if anyone could help me out with understanding the requirements for max dose it would be greatly appreciated. Also, can any of this be rationalised rather than fully tested.

Thanksin advance.
 

chris1price

Trusted Information Resource
I would agree that testing at Maximum dose is a Design Verification activity. Ideally, the product testing, packaging testing and shelf-life should be performed after exposure to maximum dose. This is the worst-case condition, and a polymer that is ok at 25kGy may well be unacceptable at the highest dose. Similarly, as the polymer degradation is time dependent, you may not identify that it is unacceptable until you reach the end of the shelf-life work. One reason for the increased number of lower VDmax values (22.5kGy, 17.kGy5, etc) in the AAMI TIR is to reduce the maximum dose.
 

planB

Super Moderator
Hi,

line with chris:

The VDmax method according to ISO 11137-2 tells you how to substantiate your routine dose of a minimum of 25 kGy, whereby "substantiate" means that you demonstrate a minimum SAL (sterility assurance level) of 10exp(-6). Any higher dose is favourable in terms of SAL, but may be unfavourable for your materials. So your maximum dose depends on your materials that you use: both your actual product materials as well as your packaging materials. Typically, material suppliers and/or material databases can provide you guidance on the maximum dose. In case you get reliable data from these sources, no additional testing for the maximum dose might be warranted.

HTH,

Gerhard
 

esraaasem22

Registered
I am looking for an SOP for gamma raddiation based on ISO 11137.
We are a manufacturer for medical devices that uses an external sterilization house and test lab. If anyone has one they using and willing to share, that would be helpful rather then trying to reinvent the wheel. Thanks in advance!
 
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