Department of Polymer Engineering, School of Chemical Engineering, University of Tehran , Tehran , Iran.
Pharm Dev Technol. 2014 Dec;19(8):952-9. doi: 10.3109/10837450.2013.846371. Epub 2013 Oct 25.
The rheological and drug release behavior of biopolymer nanocomposite gels based on the cellulose derivatives, formulated as the bioadhesive drug delivery platforms, were investigated. The bioadhesive gel is composed of the microcrystalline cellulose, sodium carboxymethyl cellulose and phosphate buffered saline (pH = 7.4 at 20 °C) as the dissolution and release medium. The reinforcing nanofillers such as MMT-clay, fumed porous silica and porous starch were used as additives in the nanogel bioadhesive. The constant steady state viscosities of this nanogels upon incorporation of various nanofillers into the systems is the sign of structural stability. Hence, this system is suitable for use in the controlled drug delivery systems in contact with the biological tissues. Based on the rheological measurements, the shear flow properties (i.e. zero shear viscosity and yield stress) were influenced by the concentration of polymers and nanoparticles. The results indicate that the nonlinear rheological data are fitted properly by the Giesekus model. Furthermore, the results showed that the nonlinear viscoelastic parameters (λ and α) are highly affected by the biogel and nanoparticles concentrations. Finally, the drug release was measured, and the results indicated that the biopolymer-clay nanocomposites have appropriate release pattern as the release is better controlled compared to the other nanogel formulations.
研究了基于纤维素衍生物的生物聚合物纳米复合凝胶的流变性和药物释放行为，将其配方制成了生物黏附性药物传递平台。生物黏附性凝胶由微晶纤维素、羧甲基纤维素钠和磷酸盐缓冲盐水（20°C 时 pH 值为 7.4）组成，作为溶解和释放介质。蒙脱土纳米粘土、气相法多孔二氧化硅和多孔淀粉等增强型纳米填料被用作纳米凝胶生物黏附剂中的添加剂。在将各种纳米填料掺入系统后，纳米凝胶的恒定稳态粘度是结构稳定性的标志。因此，该系统适用于与生物组织接触的控制药物释放系统。基于流变学测量，剪切流动特性（即零剪切粘度和屈服应力）受聚合物和纳米颗粒浓度的影响。结果表明，Giesekus 模型可以很好地拟合非线性流变数据。此外，结果表明，非线性黏弹性参数（λ 和 α）受生物凝胶和纳米颗粒浓度的高度影响。最后，测量了药物释放，结果表明，与其他纳米凝胶制剂相比，生物聚合物-粘土纳米复合材料具有合适的释放模式，因为释放得到了更好的控制。
