Preparation and Characterization of Danofloxacin Mmesylate Liposomes

Five different methods were tested and compared to prepare danofloxacin mesylate liposomes, the ammonium sulfate gradient method with freeze-thawing steps was validated as the best one; the optimal preparation condition confirmed by orthogonal experiment was as follows: EPC-CH ratio was 3 : 2 and 2.6% SA was added to gain the positive electricity; drug-lipoid was 2 : 5, the concentration of ammonium sulfate was 250 mmol · L−1, water-oil ratio was 1 : 5, and they were incubated at 35°C for 15 min. The prepared liposome products were ivory white semitransparent suspension, the electron microscope appearance was intact and globular or globular-like vesicles with uniformed distribution; the particle size was centralized from 3 to 7 μm, zeta-electric potential valued+ (15.92±1.49) mV, pH valued 6.02±0.09; HPLC method was established in quantitative analyses of danofloxacin and reverse dialysis with RP-HPLC method was validated for determination of entrapment efficiency. The entrapment efficiency results were all above 90%. They were stored at 4°C with satisfied stability. Six months later, the appearance, characters and entrapment efficiency were almost with no change.