It depends on your the activity of your reagent
Thats a bit "short".
It depends on a lot of factors: for example, is it something that will dissolve in water? Would you need to test this with fish (drugs need to be tested for this, using trout).
It depends on where it works => need to do an eye test? Or not?
It depends on what your intentions are: human drug, animal drug, microbial drug?
and about differences in mouses: this is often for certain, specific, immunological reactions (certain deficits in mouses might be needed) etc...
If you don't know it, then ask it! Better to ask and look foolish to some then not ask and stay stupid.