Hi everyone, I have recently purchased mitomycin C from SantaCruz to inactivate MEFs and since insufficient information was provided by the manufacturer on reconstitution and stability I had a read around and decided to dissolve the dry powder in PBS at a final concentration of 0.5mg/mL. I then prepared aliquots of 300uL and stored them at -20degrees protected from light. The following day after freezing I thawed a few vials to use and did not notice anything unusual (colour was nice light purple and no flocculation). However after 10 days I took some more vials out and noticed that an insoluble precipitate has formed. I did some research around and could not find anything exhaustive. Sigma says that once precipitate forms the solution becomes toxic/ineffective. However this paper (http://www.ncbi.nlm.nih.gov/pubmed/11821684) says that mitomycin in PBS retains stability up to one month when stored at -20 in PBS. I would like to ask in your experience, has this ever happened to you? Have you noticed any difference in efficacy? Many thanks in advance
Hi! I used to make aliquotes at -20 in water but also me I have noticed these precipitates and my feeders continued to grow so the concentration of mitomycin was decreased. Now I used mitomycin from Sigma and the aliquotes are conserved at 4° and you can use for 6 weeks without problem. Datasheet suggests to resuspend in water.
Why cant you store the stock solution in 100% ethanol? Ethanol will not freeze even at -80. Aliquot your stock solution and store at -20. At the time of use dilute sufficiently (1:1000 for example) in medium or PBS.
I will suggest you to make fresh solution of MMC before each and every use. I also did the same for my work........Then you need not bother about this problem...........
I also use water for dissolving and so far never observed such precipitate. Some manufacturers say the precipitate is toxic to cells and fresh solution should be prepared. You might need to do so before applying it to your cells.
It has happened de to me too and the aliquotes still worked ok. I routainely inactivate MEFs. Watch fotosensibility.
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