A stock solution may be made by dissolving the valproic acid in an organic solvent with an inert gas. Valproic acid is soluble in organic solvents such as ethanol, DMSO and imethyl formamide (DMF). The solubility of valproic acid in ethanol is about 30mg/ml and about 5mg/ml in DMSO and DMF. Further dilutions of the stock solution into aqueous buffers or isotonic saline should be made prior to performing biological experiments.
Ensure that the residual amount of organic solvent is insignificant, since organic solvents may have physiological effects as low concentrations. Organic solvent-free aqueous solutions of valproic acid can be prepared by directly dissolving the crystalline compound aqueous buffers. The solubility of valproic acid in PBS, pH 7.2, is about 10mg/ml. We do not reco -mmend storing the aqueous solution for more than one day.