文献类型：期刊文献

英文题名：Dual-response nanocarrier based on graft copolymers with hydrazone bond linkages for improved drug delivery

作者：He, Yueying[1];Zhang, Yan[1];Xiao, Yan[1];Lang, Meidong[1]

机构：[1]E China Univ Sci & Technol, Sch Mat Sci & Engn, Shanghai Key Lab Adv Polymer Mat, Key Lab Ultrafine Mat,Minist Educ, Shanghai 200237, Peoples R China

年份：2010

卷号：80

期号：2

起止页码：145

外文期刊名：COLLOIDS AND SURFACES B-BIOINTERFACES

收录：;EI(收录号：20103113112239);WOS:【SCI-EXPANDED(收录号:WOS:000281077500006)】；

基金：This research was supported by the Fundamental Research Funds for the Central Universities, the National Natural Science Foundation of China (20804015), "Shu Guang" Project of Shanghai Municipal Education Commission, Specialized Research Fund for the Doctoral Program of Higher Education (200802511021), the Natural Science Foundation of Shanghai (08ZR1406000), Shanghai Leading Academic Discipline Project (B502) and Shanghai Key Laboratory Project (08DZ2230500).

语种：英文

外文关键词：Polymeric micelles; N-isopropylacrylamide; Hydrazone bond; Dual-responsive; Poly(2-oxepane-1,5-dione-co-epsilon-caprolactone); Drug delivery

摘要：Core-shell micelles with biodegradability, thermo- and pH-response were successfully demonstrated by poly(2-oxepane-1,5-dione-co-epsilon-caprolactone) (P(OPD-co-CL)) grafted with hydrophilic segments of amine-terminated poly(N-isopropylacrylamide) (At-PNIPAM). To compare with the graft copolymer, P(OPD-co-CL) block PNIPAM polymer was also prepared. The micelles with core-shell structure were formed with both graft and block copolymers by self-assembly in aqueous solutions, of which PNIPAM shell is thermo-response. Furthermore, P(OPD-co-CL)-g-PNIPAM also showed pH-sensitivity, which was attributed to the acid-cleavable property of the hydrazone bond. The low critical micelle concentrations (CMCs) of graft polymers and block polymers were 6.7 mg/L and 14.3 mg/L, respectively, which indicated the formation of stable micelles. Both drug-free and drug-loaded micelles were in uniformly spherical shape observed by transmission electron microscopy (TEM). The sizes of the drug-free and drug-loaded micelles prepared from graft polymer were 123.5 nm and 146.5 nm, respectively, and the sizes of those prepared from block polymer were 197.5 nm and 211.5 nm, respectively. The lower critical solution temperature (LCST) for the graft polymer was 34.3 degrees C, while that for the block polymer was 28.1 degrees C, demonstrating a thermo-response. The graft polymeric micelles exhibited thermo-triggered decelerated release at pH 7.4, and pH-triggered accelerated release at 25 degrees C in vitro release test, indicating that the graft polymeric micelles could be a promising site-specific drug delivery system for enhancing the bioavailability of the drug in targeted pathological areas. (C) 2010 Elsevier B.V. All rights reserved.