Hygromycin stability at both 37¡C and 4¡C?

[Kevin Mulcahy]

Does anybody know how stable the antibiotic Hygromycin B is at 37°C and 
also at 4°C in tissue culture medium? The reason I ask this is that one 
of the transfection guides which I have consulted warns that it is very 
unstable and only lasts for 2-3 days in tissue culture medium at 37°C 
and 2 weeks at 4°C. However, none of the other transfection guides 
mention this when refering to hygromycin B selection.

Many thanks,

Kev.