Sodium Valproate Dilutions

Sodium valproate (C₈H₁₅NaO₂ ) is MW 166.19 .

Because it is a small molecule sodium salt, we prepare sodium valproate in sterile water at 0.15 M (ie 300 mOsm).

    0.15M = 25 mg/ml = 1.25 g/ 50 ml sterile H2O

Subsequent dilutions were made with sterile isotonic saline (0.15M NaCl) to preserve tonicity at 300 mOsm.

For experiments to determine effects of valproate on conditioned taste aversion, 3 concentrations were tested:

• 200 mg/kg = 8 ml/kg of 150 mM sodium valproate

• 60 mg/kg = 8 ml of 45 mM sodium valproate (15 ml of 150 mM Na Valproate + 35 ml of 150 mM NaCl)

• 20 mg/kg = 8 ml of 15 mM sodium valproate (5 ml of 150 mM Na Valproate + 45 ml of 150 mM NaCl)

(NB: 60 mg/kg is 1/2 log unit between 20 and 200 mg/kg).