I found unopened bottle with powdered insulin (100 mg) bought in 2008 and stored until now at -20C. Is it still biologically active or should I buy fresh. I would like to use it to supplement the cell culture medium.
I think I don't wanna use it. Sigma for example says that it is stable for 1 year: http://www.sigmaaldrich.com/catalog/product/sigma/i6634?lang=de®ion=DE so your sample is 4-5 years old....
Hello Marcin,
Did you checked expired date label?
I think that powdered insulin shut be fine when stored at -20C. However, please make little volume at first to check. Serum-free medium supplements such as insulin are essential for long-term growth of commonly used mammalian cell lines. When insulin is absent from media, cell may exhibit disturbances in morphology and growth rate.
Thank's
There was nothing about expiry date.
From sigma:
...it can be stored for up to 12 months at 2-8°C if it is sterile filtered...
...powdered -0°C (whatever that means), 1 year...
I have strong feeling that can be stored for many years;)
Dear Marcin, I think it can work effectively, as it is in -20C. Thanks.
Dear Marcin,
I deal with many of such questions as yours - this particular product relies on the activity of an enzyme or hormone, whichever way you want to call insulin. Temperature is a very important factor affecting the activity of an enzyme. When formulated properly an enzyme can remain usable for a long time, so long as there was no break in the recommended storage temperature. At the stated -20 C, the insulin will be stable for 1 year, just as colleagues have stated here from a SIGMA reference. However, the hidden information to many is that it can stay up to 2 years when well-stored. After that period, you will need to retest the product to verify its activity or usability. In this case, if your lot was packaged in 2008, it needed to have been re-tested in 2010. Since you haven't done that, it would be advisable to open it and test the lot against a new one proven to give expected results before proceeding with its use. If it is found okay, you will need to always run a control every time you use that 'expired' lot till its depletion.
Personally, I CANNOT guarantee its results until such verification testing is done because it is now 5 years since it was manufactured, way over the acceptable shelf life.
Thank you and let me know if that information helps.
For research purposes, Westerns, Cell culture (without animal or human use): it should be ok. If it was not exposed to moisture or bacterial contamination, it should be fine as long as it was stored at -20 at all times as dry powder. Its activity might go down even in the absence of moisture and bacterial contamination or air exposure. If you find moisture, clumping or patches of different color inside the vial, it has gone bad and you should discard it without thinking twice. I would test activity first before using it as a supplement in cell culture. I don't recommend its use for animal or human applications. Please discard of it properly if it has expired.
Hi Marcin Chrusciel did you find out if it was OK? In a similar situation have found some old stock in the freezer! Curious to see if yours was still active? Thanks!
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