[Histonet] Expiry date of NBF

[amitapandey <@t> torrentpharma.com]

Dear Histonetters,

I require one clarification on declaration of  expiry date of 4% nutral 
buffer formalin (NBF) prepared in our lab ( from 40% solution) ? 

Do you declare the expiry date of this prepared solution ? If so what 
criteria do you follow for this?

Important to mention that  we have to archive these tissue in NBF for 5 
years as part of GLP toxicology. 

Your experience or view on these points are welcomed.

Amita