Objective: To prepare injectable Shenmai thermosensitive in situ gel and to investigate its in vitro release characteristics. Method: Shenmai thermosensitive in situ gel was prepared by cold dissolution method

the content of ginsenoside Rb1 was determined by HPLC

in vitro release characteristics of Shenmai thermosensitive in situ gel was investigated by dialysis method

and release curve was fitted by drug release model equation. Result: Gelation temperature was 34.92℃

corresponding viscosity value was 1579.52 mPa·s

gelation time was 110.67 s. This in situ gel showed a newtonian fluid at a low temperature while it might be a pseudoplastic fluid when the temperature reached a certain point

in vitro release of Shenmai thermosensitive in situ gel fitted first order kinetics equation. Conclusion: Shenmai thermosensitive in situ gel had temperature sensitivity and obviously sustained-release effect.