School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore.
Biomacromolecules. 2013 Jul 8;14(7):2262-71. doi: 10.1021/bm4003915. Epub 2013 Jun 4.
A two-step process is developed to form layer-by-layer (LbL) polyelectrolyte microcapsules, which are able to encapsulate and deliver hydrophobic drugs. Spherical porous calcium carbonate (CaCO3) microparticles were used as templates and coated with a poly(lactic acid-co-glycolic acid) (PLGA) layer containing hydrophobic compounds via an in situ precipitation gelling process. PLGA layers that precipitated from N-methyl-2-pyrrolidone (NMP) had a lower loading and smoother surface than those precipitated from acetone. The difference may be due to different viscosities and solvent exchange dynamics. In the second step, the successful coating of multilayer polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) onto the PLGA coated CaCO3 microparticles was confirmed with AFM and ζ-potential studies. The release of a model hydrophobic drug, ibuprofen, from these hybrid microcapsules with different numbers of PAH/PSS layers was investigated. It was found that the release of ibuprofen decreases with increasing layer numbers demonstrating the possibility to control the release of ibuprofen with these novel hybrid microcapsules. Besides loading of hydrophobic drugs, the interior of these microcapsules can also be loaded with hydrophilic compounds and functional nanoparticles as demonstrated by loading with Fe3O4 nanoparticles, forming magnetically responsive dual drug releasing carriers.
提出了一种两步法来制备层层(LbL)聚电解质微胶囊,该微胶囊能够包封和输送疏水性药物。采用球形多孔碳酸钙(CaCO3)微球作为模板,通过原位沉淀胶凝过程在其表面包覆一层含有疏水性化合物的聚(乳酸-共-乙醇酸)(PLGA)。在 N-甲基-2-吡咯烷酮(NMP)中沉淀的 PLGA 层比在丙酮中沉淀的 PLGA 层具有更低的载药量和更光滑的表面。这种差异可能是由于不同的粘度和溶剂交换动力学。在第二步中,通过原子力显微镜(AFM)和 ζ 电位研究证实了成功地将聚电解质多聚(盐酸烯丙胺)(PAH)和聚(苯乙烯磺酸钠)(PSS)多层包覆在 PLGA 包覆的 CaCO3 微球上。研究了具有不同 PAH/PSS 层层数的这些混合微胶囊中模型疏水性药物布洛芬的释放。结果表明,随着层数以增加,布洛芬的释放减少,表明可以通过这些新型混合微胶囊来控制布洛芬的释放。除了疏水性药物的负载外,还可以通过负载 Fe3O4 纳米粒子来证明这些微胶囊的内部还可以负载亲水性化合物和功能性纳米粒子,从而形成对磁场有响应的双药物释放载体。