Preserving the residue in 4C is recommended. For longer preservation -20C is desirable though. If your residue is organic in nature, avoid keeping your sample in room temperature as it may cause contamination. Hope that helps.

P.S. Since you talked about an in vivo experiment, are you not suppose to use PBS, instead of water?

Dear

At room temperature is less than 6 hrs. But as Patra mentioned, at 4 C is recommended for not more than 24 hrs.

Regards

 Moumita Patra and Jabbal Al sa'aidi thank you for your answers

Patra : I found in some protocols, the use of physiological water

I think it's better if you dry your extract using a frezze- dryer and then dissolve the amount you need any time. Good luck.

thank you Pr Olga Lock