can you freeze media with antibiotics in it - (Nov/16/2008 )

hi all,

Is it ok to freeze media with antibiotics in it?

As far as i knew it was fine to do this but recently somebody said it can stop the antibiotics working

The media i use is DMEM/F12 with5 % FBS, along with ITS and EGF with 0.5 % penn/strep and i never had any problem using media that had been frozen and thawed prior to use.

Recently though i have had to add 50 ug/ml neomycin to this media as i have immortalised with a plasmid which has neomycin resistance as the selection marker

I normally make up a large batch of media, around 500 ml at one time containing all the ingredients then aliqout it out into 15 or so sterile 30 ml universals and freeze them, then thaw one universal as i need it, does anyone know of any issue with me doing this?

I'm just guessing here, but since antibiotic stock solutions can be frozen without causing problems, and if the media can also be frozen without problems, then I don't think freezing them in combination will be a problem.