Objective: To optimize formulation of icariin magnetic nano-liposomes and investigate their in vitro release. Method: Ultrasonic film dispersion method was used to prepare icariin magnetic nano-liposomes

with encapsulation efficiency of icariin as index

based on single factor tests

orthogonal design was adopted to optimize preparation procedure by taking hydration medium and amounts of poloxamer 188(F-68)

PEG-2000

oleic acid-modified magnetic powder.HPLC was employed to investigate in vitro release of icariin magnetic nano-liposomes in phosphate buffer solution(PBS) containing 30% methanol

mobile phase consisted of acetonitrile-water(30:70) and detection wavelength was set at 270 nm. Result: Optimum formulation was as follows:icariin-magnetic powder(2:1)

F-68 of 200 mg

PEG-2000 of 60 mg

lecithin of 500 mg

cholesterol of 150 mg

PBS(pH 7.4) as hydration medium.Entrapment efficiency of icariin magnetic nano-liposomes was (96.57±0.42)%;cumulative release rate of icariin solution was near 99.68% in 16 h

but it was over 96.51% in 72 h for icariin magnetic nano-liposomes. Conclusion: Icariin magnetic nano-liposomes have high encapsulation efficiency and a good sustained release by ultrasonic film dispersion method.