The influence of polystyrene and styrene-2-hydroxyethyl metha- crylate addition for microencapsulation

• Main Authors: Liu cheng chung, 劉政常
• Other Authors: Chen Hui
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/70014436898650695535

碩士 === 國立中央大學 === 化學工程研究所 === 83 === The investigation attempted to use PS (polystyrene) and S-H (copolymer of styrene and 2-hydroxyethyl metha crylate ) as modified agent for ethylcellulose-walled microcapsules, and the model core is theophylline. Ethylcellulose (EC) composite microcapsules were prepared by non-solvent addition phase sepa- ration method. The influences of the release rate with diff- erent composition of PS/ EC or S-H/EC composite microcapsules were discussed. From the cloud point experiment， the surfaces of microcapsules were affected by the characterization and coacer- vation time of co-wall materials. For the PS/EC system , the re- lease rate of the drug from microcapsules decreased with in- creasing addition or molecular weight of PS. Besides for the S-H/EC syrtem, the released rate of the drug from microcapsules decreased with increasing HEMA concentration, because the hydro- xy groups of HEMA increased the molecular intereaction of S-H copolymer-EC. In addition, dissolation results showed that the release rate of microcapsules could be prolonged by the addition of small amount of PS and S-H co-wall materials(1/39). It was found that the time of 50% drug released, T50 could increase to 1.6 times and 3.4 times . Especially, in the lower molecular wei- ght of PS and the higher HEMA concentration of S-H copylymer.