Objective: To determine apparent solubility and oil-water partition coefficients of total saponins from Pulsatillae Radix

then investigate its stability in vitro gastrointestinal fluid. Method: Taking saponins(B3

BD

B7) from Pulsatillae Radix as index

apparent solubilities of three kinds of components were determined by saturation method and a shake flask method was established to determine oil-water partition coefficients

stability of total saponins in vitro gastrointestinal fluid was investigated.ELSD-HPLC was adopted to determine contents of index components with mobile phase of methanol(A)-water(B) for gradient elution(0-28 min

25%-10%B). Result: B7 had the best apparent solubility in these three kinds of components.Oil-water apparent partition coefficients of three kinds of component in different pH were very low.RSD of stability of index components in vitro gastrointestinal fluid was less than 5%. Conclusion: Dissolving ability of total saponins from Pulsatillae Radix in weak alkaline environment was the highest.Lipophilicity of total saponins was weak

so it was difficult to absorb into body through intestinal wall of lipid membrane and water layer.Total saponins from Pulsatillae Radix in vitro gastrointestinal fluid was stable.