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|標題:||Investigation of the Effect of Protective Colloids upon the Properties of Ethylcellulose Microcapsules.|
|摘要:||Preparation of ethylcellulose microcapsules containing theophylline and vitamin K3 was performed by simple non-solvent addition and emulsion non-solvent addition methods in the presence of polybutadiene or polyisobutylene as a protective colloid. The effects of the protective colloid upon the properties of microcapsules with respect to the size distribution, drug content, ethylcellulose loss, and porosity were characterized. The results of microcapsules containing theophylline indicate that, in the presence of an appropriate amount of the protective colloid, the extent of aggregation was reduced and the surface became smoother and less porous. Mononucleated microcapsules were obtained by the emulsion non-solvent addition method in the presence of polybutylene. Owing to the occurrence of aggregation, the theophylline release from microcapsules appeared to follow the diffusion-controlled matrix model; the release rate being dependent upon the extent of aggregation and the porosity of microcapsules.
Mircoencapsulation of vitamin K3, a novel antitumor drug, was performed by emulsion non-solvent addition method in the presence of polyisobutylene as a protective colloid. The results showed that the release rates of ethylcellulose microcapsules containing vitamin K3 were slower than those obtained from the ethylcellulose microcapsules prepared without any protective colloid. The extent of aggregation was reduced and individually film-coated core particles formed. However, they were accompanied by formation of small empty coacervate droplets, as detected by microscopic observation.|
|Appears in Collections:||化學工程學系所|
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