Effect of block sequence of hyperbranched block copolymers on the aggregation behavior, drug solubilization and release property

Publication date: Available online 15 January 2019Source: Journal of Molecular LiquidsAuthor(s): Yutao Xue, Jie Sun, Shan Xiong, Huining Chai, Xia Xin, Guiying Xu, Teng LiuAbstractTwo hyperbranched block copolymers H904 and H90R4 which were the same in chemical composition but different in block sequence were synthesized by anionic polymerization. Commercially X shaped Tetronic block copolymers T904 and T90R4 were selected for comparison. The effect of block sequence on the aggregation behaviors of these four copolymers were studied by surface tension, transmission electron microscopy, steady-state fluorescence and dynamic light scattering. Compared with H904 and T904, higher critical aggregation concentration, the greater hydrophobicity and smaller size of the aggregates were the characteristics of the reverse sequence copolymers H90R4 and T90R4. The ability of copolymer aggregates to encapsulate and in vitro release of a hydrophobic drug olmesartan medoxomil (OM) were also evaluated. The smaller size of H90R4 and T90R4 aggregates resulted in much lower drug solubilization. However, the more tightly packing of H90R4 and T90R4 aggregates led to a stronger interaction between OM and aggregates, so the release of OM from H90R4 and T90R4 were slower. Besides, H904 and H90R4 spontaneously formed vesicles in aqueous solution, while T904 and T90R4 formed micelles. The block order and hyperbranched architecture of the block copolymers had great effects on their aggregation behavior,...

Source: Journal of Molecular Liquids - January 15, 2019 Category: Molecular Biology Source Type: research