尼莫地平PLGA微球的制备方法改良及其特性研究

用乳化 溶剂挥发法制备尼莫地平（nimodipine，NMP）PLGA微球，在油相中引入石油醚与二氯甲烷作混合溶剂，考察了石油醚对微球性质的影响。石油醚与二氯甲烷的不同体积比（0，1∶10，1∶8，1∶4和1∶2）可调节微球的固化速率，从而得到不同特性的载药微球。混合比为1∶10时，微球突释效应减轻，包封率显著提高。以PLGA浓度、投药比及混合溶剂比为考察因素进行了正交优化设计。结果表明优化后微球包封率提高52.2%，突释率降低58.8%，药物以无定形态存在于微球中，与单一溶剂组相比，微球形态有较大改善，微球缓释效应显著增强。

Modified Preparation Method and Characteristics of Nimodipine-Loaded PLGA Microspheres

The effect of petroleum ether,as an organic phase co-solvent,on the characteristics of nimodipine（NMP）-loaded poly（lactide-co-glycolide）（PLGA） microspheres prepared via the emulsion-solvent evaporation/extraction process was studied.Different ratio of petroleum ether to dichloromethane（DCM）（0,1∶10,1∶8,1∶4,and 1∶2,v/v） caused different solidification rate,leading to different properties of microspheres.At the ratio of 1∶10,the initial burst of microspheres was attenuated,and the encapsulation efficiency was improved significantly.To perform the orthogonal design for process optimization,polymer concentration,drug/PLGA ratio and ratio of petroleum ether/DCM were set as the factors for investigation.After optimization,the encapsulation efficiency of microspheres was improved by 52.2%,and the initial burst was declined by 58.8%.Drug was encapsulated in the matrix as amorphous state.Compared with microspheres prepared by single solvent,the morphology of the optimal formulation was modified evidently,therefore NMP was released in a more controlled fashion.