Controlled release of dexamethasone from microcapsules produced by polyelectrolyte layer-by-layer nanoassembly
Controlled release of dexamethasone from microcapsules produced by polyelectrolyte layer-by-layer nanoassembly
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DOI：
10.1007/s11095-005-2600-0
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发表时间：
2005-05-01
影响因子：
3.7
通讯作者：
de Villiers, MM
中科院分区：
文献类型：
--
作者：
Pargaonkar, N;Lvov, YM;de Villiers, MM
目的为了扩大静电逐层自组装核壳结构在药物释放方面的应用，本研究报道了地塞米松从聚电解质壳层包裹的微晶中的控制释放。方法采用静电逐层自组装工艺，通过交替吸附带正电的聚二甲基二烯丙基氯化铵、带负电的聚苯乙烯磺酸钠，并根据带负电的明胶A或明胶B在带负电的地塞米松颗粒表面的pH值，制备出具有最多5层双层结构的地塞米松颗粒。用石英晶体微天平、微电泳法、微量热法、共聚焦显微镜和扫描电子显微镜对纳米薄壳进行了表征。用垂直Franz型扩散池测定了地塞米松微囊在水或羧甲基纤维素凝胶中的体外释放。结果地塞米松微晶悬浮液在PDDA溶液中超声不仅减少了聚集性，而且减小了亚微米颗粒的尺寸。在这些单分散核周围组装多层聚电解质层可在药物微晶周围形成一层聚电解质多层壳层，该壳层可根据药物微晶的组成和层数进行控制释放。结论采用LBL工艺对地塞米松微晶进行直接表面修饰可制得单分散混悬液，并通过聚电解质多层壳层实现药物的扩散控制缓释。
Purpose In an effort to expand the application of core-shell structures fabricated by electrostatic layer-by-layer (LbL) self-assembling for drug delivery, this study reports the controlled release of dexamethasone from microcrystals encapsulated with a polyelectrolyte shell.Methods The LbL self-assembly process was used to produce dexamethasone particles encapsulated with up to five double layers formed by alternating the adsorption of positively charged poly(dimethyldiallyl ammonium chloride), negatively charged sodium poly(styrenesulfonate) and depending on the pH positively or negatively charged gelatin A or B onto the surface of the negatively charged dexamethasone particles. The nano-thin shells were characterized by quartz crystal microbalance measurements, microelectrophoresis, microcalorimetry, confocal microscopy, and scanning electron microscopy. In vitro release of dexamethasone from the microcapsules suspended in water or carboxymethylcellulose gels were measured using vertical Franz-type diffusion cells.Results Sonication of a suspension of negatively charged dexamethasone microcrystals in a solution of PDDA not only reduced aggregation but also reduced the size of the sub-micrometer particles. Assembly of multiple polyelectrolyte layers around these monodispersed cores produced a polyelectrolyte multilayer shell around the drug microcrystals that allowed for controlled release depending on the composition and the number of layers.Conclusions Direct surface modification of dexamethasone microcrystals via the LbL process produced monodispersed suspensions with diffusion-controlled sustained drug release via the polyelectrolyte multilayer shell.