Preparation of thermo- and pH- sensitive star copolymers via ATRP and used in drug release application

• Main Authors: Shu-Ping Hsu, 徐淑屏
• Other Authors: 芮祥鵬
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/89c7ku

碩士 === 國立臺北科技大學 === 有機高分子研究所 === 102 === The goal of this study is to evaluate if the star-copolymers have the potential for oral drug delivery system. We synthesized thermo- and pH- sensitive star copolymers, a star-poly(NIPAAm-co-IAM) with β-cyclodextrin (β-CD) produced by atom transfer radical polymerization (ATRP), in which the esterification of β-CD hydrodyl groups reaction with 2-bromopropionyl bromide produce β-CD-core initiator with 18.74 initiation sites. The results indicates that the LCST values of star copolymers increased as hydrophilic monomer feed molar ratio of IAM, having increased lower copolymer content in water media and higher pH value. By DLS measurement observation, it was found the particle becomes a smaller size with increasing temperature, in which diameters were about 104-208nm. It was also found that the size of the micelles increased with the pH values increasing. This is probably due to the ionization of carboxyl groups of the IAM segment with high pH value. The TEM images revealed that the morphology of micelle can self-assemble into core-shell spherical structure of copolymer within IAM. The drug release experiment were conducted under four different environment conditions, observed at pH7.4 and 37℃. The copolymer containing the cumulative drug release had the best overall performance, which means the carrier may be resistant to attack under acidic condition. Thus, the human digestive system will provide good absorption, confirming that the carrier has temperature- and pH- sensitive, therefore is subjective to becoming a new drug carrier with dual stimulation response function type.