Abstract:

Objective  To study the preparation of melatonin (MLT) liposomes and their physico-chemical property. Methods  Liposomes were prepared by a film dispersion method. Based on a single test, the optimum formulations and the preparation technology were optimized by a uniform experiment. Morphology of the liposomes was detected by transmission electron microscopy. The Zeta potential and particle size distribution were evaluated by laser scattering. High speed centrifugation was applied to separate the free drug and liposomes. The entrapment efficiency and drug loading were determined by UV. The release character of melatoninliposomes was studied by the dialysis method. Results  The optimal formula was obtained by a uniform design: the phosphatides to cholesterol ratio was 25∶1, and the drug to lipid ratio was 1∶10, 40℃. The liposomes were a multi-layer spherical orellipsoidal shape with a uniform size. The mean diameter of melatonin liposomes  was(5.542±0.04)μm. The Zeta potential was -31.68?mV. The drug loading and entrapment efficiency of melatonin liposomes were (77.23±2.51)% and (3.60±0.29)%, respectively. In vitro release could be sustained for 72h and conformed to bio-exponential kinetics (rα=0.988?6 and rβ=0.9874). Conclusion  Melatonin liposomes made by using the film dispersion method have a high encapsulation efficiency and have a good delayed-release property in vitro.

Key words: Melatonin; Liposome; Film dispersion method; Release in vitro