Determination of equilibrium solubility and oil/water partition coefficient of dauricine by HPLC

Objective:To determine the equilibrium solubility of dauricine at various pHs and its oil/water partition coefficient in the n-Octanol-buffer solution system.Methods:An HPLC method was established to determine the concentration of dauricine.A shake flask-HPLC method was applied and the value of oil/water partition coefficient was calculated by the concentration ratio of dauricine in n-octyl alcolhol and water phase.Results:At 37 ℃ both the equilibrium solubility and the oil/water partition coefficient increased with the increasing pH.Conclusions:Both equilibrium solubility and oil/water partition coefficient of dauricine are affected by pH;this method can be used to accurately determine the equilibrium solubility and oil/water partition coefficient of dauricine and help to predict its behavior in vivo.