分别以相对分子质量为25 000、60000、100 000的聚(D,L)乳酸(PDLLA)为壁材,PVA-1788为乳化剂,采用乳化溶剂挥发法制备PDLLA-毒死蜱微胶囊,考察工艺条件对微胶囊粒径的影响,通过光学显微镜、扫描电子显微镜、激光粒度分布仪、高效液相色谱(HPLC)等表征PDLLA-毒死蜱微胶囊性能,并采用柱层析法评价了3种PDLLA-毒死蜱微胶囊的缓释性能.结果表明,工艺条件对微胶囊的粒径有显著影响,当PVA-1788质量分数为1.25％,连续相与有机相体积比为4∶5,PDLLA与毒死蜱质量比为2∶1时,可获得球形规整、粒径较小的微胶囊.PDLLA相对分子质量的改变对微胶囊的外观、粒径大小及分布、载药量和包覆率均无显著影响.3种PDLLA微胶囊对毒死蜱均具有明显的缓释效应,释药19 d,药物累积释放量分别为88.76％、76.74％、65.64％,其中,相对分子质量25 000的PDLLA-毒死蜱微胶囊释药速率最快.%Poly-D,L-Lactides (PDLLA1, PDLLA2 and PDLLA3) with molecular weight of 25 000, 60 000 and 100 000 respectively were used as coating material and, polyvinyl alcohol (PVA-1788) was used as emulsifier to prepare PDLLA-Chlopyrifos microcapsule by emulsion solvent volatilization method. The effects of process conditions were studied. The performance of PDLLA-Chlopyrifos microcapsule was characterized by optical microscope, scanning electron microscope, laser particle size distribution device and high performance liquid chromatograph and the performance of sustained release of three kinds of PDLLA-Chlopyrifos microcapsules was studied by column chromatography. The results showed that process conditions had a significant effect on microcapsule diameter, and microcapsule with regular sphere and small diameter could be obtained when PVA-1788 concentration was 1.25%, volume ratio of continuous phase and organic phase was 4.5 and weight ratio of PDLLA and Chlopyrifos was 2:1. The molecular weight of PDLLA had little effect on appearance, diameter and distribution of microcapsule. Three PDLLA-Chlopyrifos microcapsules showed significant sustained-release effect. And the accumulated release of PDLLA1, PDLLA2and PDLLA3 19 d after administering were 88.76%, 76.74% and 65.64%, respectively, among which PDLLA1 with the lowest molecular weight (25 000) had the fastest speed of release.
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