中文摘要：

超临界逆向蒸发法是利用超临界流体代替有机溶剂制备脂质体的方法，具有对水溶性药物脂质体制备过程简单、包覆率高等特点。文中利用该方法制备出了甲硝唑脂质体，并详细考察了不同工艺条件对脂质体粒径和包覆率的影响。结果表明：用超临界逆向蒸发法可成功地制备出平均粒径190—350nm、包覆率最高可达48．2％的甲硝唑脂质体。温度、压力和pH值对粒径和包覆率都有较大影响：温度升高、压力增大及溶液pH值从1上升至11的过程中，粒径增加至最大值然后逐渐减小，而包覆率增加至最大值后呈现显著下降的趋势。实验表明甲硝唑脂质体包覆率更容易受实验参数的影响。

英文摘要：

Supercritical reverse phase evaporation （SRPE） is a new technique for preparation of liposome with supercritical fluid instead of organic solvent. The process has the features of simple process and high coating ratio for water-soluble substances. The metronidazole liposomes were synthesized by the technique of SRPE. The effects of the process parameters on the particle size and the coating ratio of liposome were investigated. The liposomes with a volume average diameter of 190-350 nm were successfully prepared by this technique. The coating ratio for metronidazole liposomes was as high as 48.2%. The result shows that the temperature, pressure and pH have great effects on the particle size and the coating ratio. With the increase of temperature and pressure as well as the increase of solution pH from 1 to 11, the particle size increases to a maximum and then gradually decreases. While the coating ratio increases to the maximum and then presents a significant downward trend with the changes of the above parameters. It indicates that the coated ratio of metronidazote liposomes is more susceptible to the influence of the experimental parameters.