Dissertation > Medicine, health > Pharmacy > Pharmacy

Study on the Preparation of Biodegradable Microparticle and Its in Vitro Drug Release Kinetics

Author LiJin
Tutor DingFuXin
School Tsinghua University
Course Chemical Engineering and Technology
Keywords Controlled release drug delivery system Microspheres Biodegradable materials Degradation Drug release mechanism
Type PhD thesis
Year 2008
Downloads 783
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Biodegradable drug-loaded microspheres in recent years, sustained and controlled release drug delivery systems, research focus, small size, diversity and versatility of the carrier material and applicable in a variety of modes of administration, on the release rate by control to significantly improve the safety and effectiveness of clinical medicine. In this paper, PLGA - poly ethylene glycol monomethyl ether copolymer (PLGA-mPEG) as the material for the development of drug-loaded microspheres loaded microspheres for drug release mechanism studies insufficient, from the microscopic structure of the microspheres and performance relationship, the analysis of the degradation of the material on the release behavior of the mechanism for the design and application of the guidance controlled release drug-loaded microspheres prescription. Small the hydrophobic molecule drugs methotrexate (MTX) as a model drug, examine the impact and the causes of the emulsion solvent evaporation method of process parameters on the nature of the drug-loaded microspheres. Through the orthogonal process optimization, higher encapsulation efficiency and sustained-release effect of MTX microspheres were prepared. The experiments show that the MTX and the material has a good compatibility. Certain drug loading process of release of MTX microspheres showed obvious three stages, including the initial burst release period, when demurrage and secondary burst release period. Microspheres degradation kinetics of the microspheres in the degradation process of the physical and chemical changes that occur with some regularity, and morphological changes differ for the different stages of drug release, degradation factors also control the release of the microspheres. The presence of the hydrophilic block is polyethylene glycol monomethyl ether (mPEG), accelerated the degradation rate of the material, to improve the flexibility of the material, thereby reducing the risk of the microspheres by external damage and chipping explanation drug, but also makes release demurrage greatly shortened. Microspheres degradation by its own nature and the release environment factors, these factors affect the degradation of the material on drug release indirect regulation. Paper studied the material composition of the four factors of drug loading, particle size as well as the release of environmental degradation kinetics mode of action of MTX microspheres, and then analyze each factor control law for a different release stage from which to expand the adjustment the release rate of the microspheres way to achieve controllable release rate of microspheres of important guiding significance. The mass transfer model describes the diffusion of the drug and the degradation of the material MTX microspheres release process, and the applicability of the model to research. Analyzed the relationship between the main factors affecting the degradation of the material and the drug diffusion coefficient, and the impact of the trend to make predictions. PLGA-mPEG and the compatibility of the hydrophilic drugs, were prepared microspheres of salbutamol sulphate (SBS), and lysozyme (LYS) microspheres. Serious burst release, the stagnation of the late release of the active macromolecules, adding additional agents to improve the preparation process for the encapsulation of hydrophilic drugs microspheres low, other methods to improve the quality of the microspheres.

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