论文部分内容阅读
Generally speaking, linear conpolymers whose stability increased accompany with the adding of molecular weight, has hindered further adhibition of polymeric micelles due to poor ability in the field of nano-based drug delivery system (DDS) and targeting administration domain.However, star-shaped polymers with the advantages of smaller diffusion coefficient, lower solution viscosity and smaller hydrodynamic radius qualified themselves with strong anti-dilution property, enabling a new development of polymeric micelles.In this study, a new kind of stable and bio-compatible nano-carrier based on star-shaped diblock polymeric micelles were designed and investigated.With reversible addition-fragmentation chain transfer (RAFT) method, the amphiphilic diblock copolymers,comprised of beta-cyclodextrins core segments and poly (acrylic acid-co-methyl methacrylate)-b-poly (N-vinyl pyrrolidone) arms were synthesized, which were different in molecular weight (β-CD-[P(AA-co-MMA)-b-PVP]4, brief for β-CD-P4).Benefiting from its excellent biocompatibility and modifiable property, β-cyclodextrin was employed as the core part of this four-armed polymer.Meanwhile, among seven secondary hydroxyl groups of the smaller opening of β-cyclodextrin, four hydroxyls were decorated with hydrophobic and hydrophilic substituents to construct the four arms of β-CD-P4.Micellization behaviors of this star-shaped polymer (β-CD-P4) were detected by critical micelle concentration (CMC), drug loading efficiency (DL) and in vitro drug release indicators.Those Results showed that β-CD-P4 were capable to self-assemble under a very low concentration of 5.852× 10-3mg/1.And with a high DL of 12.7% and 66.4nm mean particle size, this star polymer exhibited a sustainable and controlled-release property at physiological pH condition.In vivo tissue distribution demonstrated that compared with vinpocetine (VP) injection,VP-loaded star-shaped polymeric micelles (VP/β-CD-P4 micelles) prepared by a solvent evaporation method showed an apparent lung targeting character, whose targeting efficiency (Te) was 8.98 times higher than VP injection.Herein, those results making β-CD-P4 an excellent candidate for application in the fields of nanoparticle drug delivery system and pulmonary targeting administration.