中文摘要：

针对商品化聚乳酸微球粒径分布较宽难于适用气溶胶给药要求的不足,采用水力空化混合强化超临界流体辅助雾化技术（SAA-HCM）制备聚乳酸（PLA）超细微粒.该技术主要特点是通过在超临界流体和液相进料处引入水力空化混合器,强化两相间的混合.考察SAA-HCM过程混合器压力、温度、沉淀器温度、进料中CO2与液体溶液质量流量比和溶液质量浓度等操作参数对微粒形态和粒径分布的影响,成功制备出球形度较好,粒径分布较窄（1～3μm）的PLA微球.经X射线衍射（XRD）分析和差示扫描量热（DSC）分析显示,与原料PLA相比,微球晶型及热曲线变化不大,但结晶度下降.同时把操作参数与相行为进行关联,探讨了影响颗粒形貌的机理.对比超临界流体辅助雾化法（SAA）的实验结果表明：水力空化的引入能有效强化混合器内的两相传质,混合更好,能制备出适用于气溶胶给药要求的超细微粒.

英文摘要：

To resolve the problem of wide particle size distribution of the commercial poly（lactic acid）（PLA）microspheres for aerosol delivery,a novel technique named supercritical fluid assisted atomization introduced by hydrodynamic cavitation mixer（SAA-HCM）was developed to prepare the PLA microparticles.The primary advantage of SAA-HCM is the intensifying mixing between supercritical carbon dioxide,and liquid feedstock by introducing a hydrodynamic cavitation mixer.The effects of different process parameters such as mixer pressure,mixer temperature,precipitator temperature,mass flow ratio between carbon dioxide and liquid solution,and solute concentration were investigated to evaluate their influences on the morphology and size distribution of precipitated particles.Microparticles of PLA was successfully prepared with a narrow particle size distribution（1-3μm）and well-defined spherical shape at optimized conditions.Compared with the untreated PLA,X-ray diffraction（XRD）and differential scanning calorimetry（DSC）results suggested that there were no significant changes in crystalline type and heat properties,but prominent decrease in the crystalline of the resulting PLA products was observed.Considering the phase behavior,the influencing mechanism of the process parameters on the microparticle morphology was interpreted briefly.The results indicated that in contrast with SAA,the intensification of the mass transfer between the two phases in the mixer was verified and very sharp PSD can be obtained,that lies in the particle size range of aerosolizable drugs.