How to validate Device Shelf Life?

[SteveK]

I have submitted a TF for a NB review for a new device. It is a non-sterile 12V DC pneumatic device (with simple firmware) which does not come into contact with the patient. In the TF dossier section I indicate a shelf life of 5 years (like we quote for all our products). The TF reviewer is now asking for validation or verification data to support the life of the device. How am I supposed to supply such data other than leave it (on the shelf) for 5 years and see if it still works after this time? I cannot see how some sort of accelerated aging test would be relevant, we are not talking about putting it some cycle testing etc since 'shelf life' in my understanding relates to not using the product i.e. distinct from product life cycle. So how can I respond?

Any thoughts?

Steve

 

[MIREGMGR]

Shelf life is usually considered to be related to various mechanical failures occurring due to physico-chemical processes and the passage of time.

Because most chemical reaction speeds are related to temperature, shelf-storage-simulative passive accelerated aging at elevated temperature is considered to be an adequate, approximate way of obtaining information about shelf life while sufficient time passes for real time aging studies to be completed.

Such data usually is obtained by putting a sufficient number of units of the packaged product on a shelf-like rack in an accelerated aging testing chamber, setting it to an appropriate test cycle, and running it for the appropriate test time for your total desired shelf life claim. Usually you do intermediate product removals at each "year" test point to track progress and discover problems as early as possible.

Probably your reviewer is asking for such accelerated aging data.

 

[SteveK]

Shelf life is usually considered to be related to various mechanical failures occurring due to physico-chemical processes and the passage of time.

Because most chemical reaction speeds are related to temperature, shelf-storage-simulative passive accelerated aging at elevated temperature is considered to be an adequate, approximate way of obtaining information about shelf life while sufficient time passes for real time aging studies to be completed.

Such data usually is obtained by putting a sufficient number of units of the packaged product on a shelf-like rack in an accelerated aging testing chamber, setting it to an appropriate test cycle, and running it for the appropriate test time for your total desired shelf life claim. Usually you do intermediate product removals at each "year" test point to track progress and discover problems as early as possible.

Probably your reviewer is asking for such accelerated aging data.

Basically I think the request is totally unreasonable so I have now put this in my TF

Device Shelf Life

“The ABC123 has a recommended shelf life of 5 years (i.e. it should be fully inspected and retested before installation if stored unused for this period – noting it is not a sterile product) and is given a manufacturers warranty of 5 years (the time in which we would repair or replace a faulty product).”

Note the italics are what I have now added to my original statement.

In a different life I did conduct aging/stability tests as you suggest. However for my TF component parts I am using the guidance (section) given in NB-MED/2.5.1/Rec5 i.e.:

'(vii) identification of ‘shelf-life’ reflected
by any ‘use by’ date, or
other ‘lifetime’ of the device(s)

In certain cases, such restrictions on use will reflect a time-related deterioration in characteristics that are important to product safety and performance. In other cases, however, the restrictions will be based on other considerations. The ‘lifetime’ of an active device, for example, may be determined by the period for which the manufacturer will support the device by way of availability of spare parts, manuals, training, service/repairs etc.'

I don’t believe I fall under ‘certain cases’ with the Class IIa device I referred to and there no indication of validation in this respect. Basically I will just have to ‘stand my ground’ with our NB reviewer.

As a positive note and a follow up of another thread (http://elsmar.com/Forums/showthread.php?t=53564) the NB did turn round the TF review within 30 days!

Steve

 

[plantengineer]

An oldie but a goodie....

http://www.mddionline.com/article/g...ed-protocol-accelerated-aging-medical-devices

 

[DesiQE]

I am at a loss to explain to management when aging starts for a finished device.

When does aging of a device begin? When it is manufactured or when it is sterilized? Let's say, the aging study was done using sterile products and aged for 2 years. If I were to "manufacture" a device and keep unsterile on the shelf for 6 months, can I still claim 2 years once I sterilize it or would it now reduce to 1.5 years? Been mulling this question around for a bit with various folks and everyone has a different opinion. Your opinion would matter a bit.

I am not even going down to the component level here.

Thank you.

 

[MIREGMGR]

When does aging of a device begin? When it is manufactured or when it is sterilized?

Shelf life often refers to the period over which a stored product can be pulled from storage and assuredly will provide proper functionality, not including consideration of sterility.

Shelf life however can also mean the period during which, for a sterile product, the sterile barrier packaging assuredly maintains its barrier functionality and therefore the sterilization is valid.

In most cases, the answer to your question will come from which definition is meant for "shelf life". If the question pertains to sterility, the period normally is counted from which the device is sterile barrier packaged, since that date of course is before sterilization. This is conservative. If the question pertains to functionality, the period normally is counted from date of manufacture.

A possible exception to the latter might be if there is something about the product's materials or other characteristics that is especially challenged by sterilization in such a manner that the relevant functionality-impairing aging process is initiated or significantly accelerated by the sterilization process itself. This however in my experience would be rare, and in any case an undesirable design if any alternative was possible.

 

[DesiQE]

Thank you.

Let's assume it is a typical vascular catheter made of plastic tubing,and bonding and laser welding is used to join different components. And the catheter is sterilized 2x and accelerated aged for 2 years. Then shelf life is given for 2 years on the label. But, in reality the product will be made and stored for one year, then sterilized and then given 2 years on the label. Is this acceptable and if so, how and why?

 

[blargon]

It'd be acceptable if the product is stored for 1 year, sterilized twice and accelerated aged for 2 years. Start a real time shelf life study with products that have been stored for 1 year, sterilized twice to be able to validate the accelerated aging results.

 

[DesiQE]

Thank you. So that would mean I do need to "test" the 1 year of storage aging. Correct? That is to say, the aging study shall contain the storage time as well?