Hi,

As not mentioned, how does it make to 25% (is it in H2O or ethanol). You can concentrate it first then make your desired doses. Usually, we make dry powder from the plant (s) of interest with solvents. Then dissolve in water or other non-toxic solvent and tested against cell lines after determining EC50 or IC50 etc.

You can determine EC50 first then use different doses for the activity of your extract.

Good Luck!

it is an ethanolic extract, absolute ethanol and the IC50 is 30

Then you can go from 3 to 10, depends how many doses you want to try...