Preparation Of PLGA-PGA Microspheres Containing Drugs By Membrane Emulsification Technique

At present biodegradable materials have more and more applications in medical science, biodegradable polymers have well biocompatibilities and biodegradabilities, drug-loading biodegradable polymer microspheres could realize the controlled drug release. The traditional process of the preparation of microspheres exist shortcomings such as low uniformity and low preparation of repeatability, low encapsulation efficiency. The drug-loading biodegradable microspheres with uniform particle size, high. encapsulation efficiency and controlled drug release were preparaed by combining membrance emulsification technique and multiple emulsification method.At first, we prepared biodegradable polymers such as PLGA, PBLG and PLGA-PGA, and these biodegradable polymers were also investigated by 1H-NMR and FT-IR.Secondly, we inspected the influence of experimental conditions on preparation of drug-loading microspheres by membrance emulsification technique. This chapter chose 2.6μm SPG membrance for research, using PLGA as a carrier materials,bovine serum albumin as model drugs. The stability of primary emulsion was studied, the influence of the dosage of emulsifier and the choose of organic solvents on stability of primary emulsion were studied. The membrance emulsification technic procedure parameters on preparation of drug-loading microspheres. The influence of operating pressure, stirring speed and curing procedural stirring speed on preparation of drug-loading microspheres were studied. According to this chapter experiment content,the dosage of emulsifier is 20mg, the ratio of the ratio of methylene chloride and toluene in oil phase is 1:2,operating pressure is 0.014MPa, stirring speed is 180rpm, curing procedural stirring speed is 120rpm. The influence of inner aqueous phase particulates size on preparation of drug-loading microspheres and inner aqueous phase additive were studied, the morphology of drug-loading microspheres, encapsulation efficiency and the release behavior were observed. According to this chapter experiment content, drug-loading microspheres with smaller inner aqueous phase particulates size have smooth surface, highly monodisperse and higher encapsulation efficiency. the release behavior of drug-loaded microspheres with smaller inner aqueous phase particulates size have the lower initial release and more stable release. Encapsulation efficiency of rug-loaded microspheres was effectual improved by adding 0.5%(ω)PEG in inner aqueous phase. Drug-loaded microspheres have smooth surface by adding PEG in inner aqueous phase.Finally, drug-loading microsphere with PLGA and PLGA-PGA as carrier materials were separate prepared. PLGA microspheres containing BSA were prepared by membrance emulsification technique with 2.6μm SPG membrance, these microspheres have with uniform particle size and smooth surface, encapsulation efficiency is 90.1%, accumulative release in 50d is 82.2%. Microspheres with different particulates size were prepared by SPG membrance with different aperture size, the reason of different morphology was studied. PLGA-PGA microspheres containing drugs were prepared, This study provides a method for drug of intestinal absorption type,has a positive market prospect.