Preparation Of PLGA Microspheres By Using SPG Membrane Emulsification

This study use PLGA as microspheres material by combining a new emulsificationmethod—SPG membrane emulsification technique, prepared two kinds of microspheres,nimodipine microspheres and lysozyme microspheres. And then the drug loading and invitro release effect were evaluated and made a preliminary evaluation of other propertiesfor the two types microspheres.During the preparation of nimodipine microspheres with O/W emulsion methods，theprescription of it was decided by investigate the various factors which may affect themicrospheres, such as the PLGA viscosity, the concentration in oil phase, etc. And thenthe appearance of the microspheres, drug loading and release behavior were used asindicators to decide the best prescription. Then the best prescription was used to preparethe nimodipine microspheres, characterized the microspheres. Its drug loading was16.33%, the encapsulation efficiency was97.98%, and the particle size is45.180μm. Itsin vitro release compared with nimodipine powder demonstrated good release properties,consecutive40days to release55%, in line with Ritger-peppas release equation. DSCresults showed that the amorphous nimodipine is wrapped in the form of microspheres.At the same time, we using W/O/W emulsion of the lysozyme, PLGA microspheresprepared by the same factors of preparation process of prescription. Results show that theprescription factors of nimodipine microspheres, the material viscosity and the dosage of microspheres has a great influence on encapsulation efficiency, in addition, due to themultiple emulsion method to prepared microspheres, which the volume of internal waterphase and additive also has a large effect on protein microspheres preparation. Accordingto the optimized conditions of lysozyme microspheres drug loadings was11.84%, theencapsulation efficiency was72.43%, the average particle size is63.89μm. But its invitro release for a week is only about40%, then release less and less, and shown asincomplete release. The DSC characterization of lysozyme microspheres and infraredcharacterization showed that lysozyme was wrapped inside the microspheres; Hemolysistests showed that the preparation of lysozyme microspheres suspension liquid has nohemolysis phenomenon; The degradation in vivo and in vitro showed that in vitrodegradation of7weeks are almost without the ball, the tissue section showed themicrospheres has little degradation in vivo test, and has a good histocompatibility.This research mainly studied the SPG membrane emulsification. The preparation use theSPG membrane emulsification method with fat-soluble medicine microsphere and proteinmicrospheres and a preliminary evaluation on the properties of microspheres can providethe appropriate reference for the use of SPG membrane emulsification.