Preparation and quality evaluation of bryostatins freeze-dried liposomes / 第二军医大学学报

ABSTRACT

Objective: To prepare bryostatins freeze-dried liposomes and to establish a quality standard for the liposomes. Methods: Film dispersion technique was used to encapsulate bryostatins with liposomes. Chloroform was taken as the solvent and was volatilized by revolving. Emulsification was performed with the probe after hydration, then the supporting agent was added for freeze drying. An RP-HPLC method was developed to determine the freeze-dried liposome content. The separation was performed with a Agilent C18 Column and the mobile phase was methanol-water in gradient elution 75 25 (0-38 min), 73.7 26.3(38-45 min), 79 21(45-48 min) by a flow rate of 1.5 ml/min, with the UV detector set at 228 nm. Zetasizer was used to determine the size of liposomes and the entrapment efficiency was determined with centrifugal ultrafilter. Results: The freeze-dried liposomes were homogeneous and the mean diameter was 0.423 μm. The standard curve was linear over the range of 44-220 μg/ml, r=0.999 8. The intra-day and inter-day RSDs were less than 2.0 %. The recoveries of the high, middle and low concentrations (88, 110, and 132 μg/ml) were 100.8 %, 98.4 %, and 100.9 %, respectively. The detection limit was 4.4 ng, the quantitation limit was 17.6 ng, and the entrapment efficiency was 98.68 %. Conclusion: The film dispersion technique is suitable for preparation of bryostatins liposomes. The method in this study is easy-to-use, accurateg and with good repeatability.