Spg Membrane Emulsification Monodispersed Sexual Drug-loaded Microcapsules,

In the drug delivery system, a majority of polypeptides and protein drugs are water-soluble, but the biodegradable polymers, as the carrier material, are oil-soluble, it is very difficult for the preparation of drug-loaded microcapsules. The emergence of Water-oil-water (W/O/W) multiple emulsion-solvent evaporation method effectively solved the problem, had been widely used in the field of drug delivery system. Usually, the water-oil-water (W/O/W) multiple emulsions were prepared by ultrasound, homogenization or mechanical stirring. However, the problems of the lowly encapsulation efficiency, the burst release of drug and the cohesion and inactivation of drug were frequently appeared, no matter what kind of the above-mentioned preparation methods were used. In the nineties of the 20th century, the emergence of Shirasu Porous Glass(SPG) membrane emulsification technique effectively solved the above problems. Membrane emulsification technology is a new type of emulsion preparation methods, with the obvious advantages of low energy consumption, simple operation, reproducibility, narrow size distribution of the obtained products and the controlled size of products.Firstly, the paper investigated the influences of experimental conditions on BSA-loaded microspheres. The researches as follow:Firstly, the paper investigated the influences of the type of emulsifier, emulsifier concentration and the oil phase density on primary emulsion stability. The effect of press, stirrer speed and solidification time on encapsulation efficiency and the release behavior of BSA-loaded microcapsules were studied. PLGA and BSA were used in the experiment of this chapter. It was demonstrated that the encapsulation efficiency reduced when press was increased; when stirrer speed was more than 200rpm, the encapsulation efficiency also reduced by the increase of stirrer speed; the encapsulation efficiency was highest when solidification time was 5 hours. The influences of primary emulsion droplets size on BSA-loaded microspheres were investigated. It was demonstrated that primary emulsion droplets size had an important influence on microspheres surface morphology, encapsulation efficiency and release behavior. When primary emulsion droplets size was reduced, the diameter of holes on microspheres wall also was reduced, the encapsulation efficiency was increased, the highest encapsulation efficiency reached 90%, and the initial release was decreased.Secondly, BSA-loaded microcapsules were prepared by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and multiple emulsion-solvent evaporation method with poly(lactic-co-glycolic acid)(PLGA) as the carrier material. Compared with mechanical stirring method, the encapsulation efficiency of microspheres which prepared by membrane emulsification technique was obviously higher, the highest encapsulation efficiency reached 93.72%. Initial release was lower when microcapsules were prepared by Shirasu Porous Glass (SPG) membrane emulsification technique, and the total release achieved 80% in a month.Lastly, the preparation of insulin-loaded microcapsules by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and solid-oil-water (S/O/W) method was investigated. By using methods of isoelectric points deposition, insulin nanoparticles was successfully achieved within the range of 30-50nm. Insulin-loaded microcapsules were prepared by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and solid-oil-water (S/O/W) method. It was demonstrated that the amount of holes on microspheres wall was relatively small by using S/O/W method; the encapsulation efficiency was relatively low by using S/O/W method, the highest encapsulation efficiency only reached 71.55%; initial release was relatively lower by using S/O/W method, in view of the overall situation, the behavior of drug release lasted for two weeks.