Controlled-release formulations for hydroxy urea and rifampicin using polyphosphate-anion-Crosslinked chitosan microspheres
Controlled-release formulations for hydroxy urea and rifampicin using polyphosphate-anion-Crosslinked chitosan microspheres
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DOI：
10.1002/app.25881
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发表时间：
2007-05-05
影响因子：
3
通讯作者：
Jabrail, Fawzi Habeeb
中科院分区：
文献类型：
--
作者：
Gupta, K. C.;Jabrail, Fawzi Habeeb
以三聚磷酸钠（STPP）和六偏磷酸钠（SHMP）为阴离子交联剂，制备了物理交联的利福平和羟基脲控释微球。已发现具有恒定脱乙酰度（75wt%）和恒定分子量（1134 kg/mol）的壳聚糖可用于所选药物的控制释放。用SHMP阴离子交联剂制备的微球比用STPP阴离子交联剂制备的微球在形状和尺寸上更疏水且更致密。SHMP-阴离子交联微球在pH 3时显示最佳负载，而STPP-阴离子交联微球在pH 4时显示最佳负载。STPP-阴离子交联微球适用于利福平的控释，而SHMP-阴离子交联微球适用于羟基脲的控释。物理交联的壳聚糖微球的药物释放特性的解释相对于它们的大小和封装的药物与聚合物基质和阴离子交联剂的离子相互作用。负载药物的初始突释本质上是Fickian的，并且遵循一级动力学，但是药物释放的受控步骤显示非Fickian的性质，并且遵循零级动力学。(c)2007 Wiley Periodicals，Inc.
Physically crosslinked microspheres for the controlled delivery of rifampicin and hydroxy urea have been prepared with sodium tripolyphosphate (STPP) and sodium hexametaphosphate (SHMP) anion crosslinkers. Chitosan with a constant degree of deacetylation (75 wt %) and a constant molecular weight (1134 kg/mol) has been found to be useful for the controlled release of selected drugs. The microspheres prepared with the SHMP anion crosslinker are more hydrophobic and compact in their shape and size than the microspheres prepared with the STPP anion crosslinker. The SHMP-anion-crosslinked microspheres show optimum loading at pH 3, whereas the STPP-anion-crosslinked microspheres show optimum loading at pH 4. The STPP-anion-crosslinked microspheres are suitable for the controlled release of rifampicin, but the SHMP-anion-crosslinked microspheres are suitable for the controlled release of hydroxy urea. The drug-release characteristics of the physically crosslinked chitosan microspheres are explained with respect to their size and the ionic interactions of the encapsulated drugs with the polymer matrices and anion crosslinkers. The initial burst release of the loaded drugs is Fickian in nature and follows first-order kinetics, but the controlled step of the drug release shows a non-Fickian nature and follows zero-order kinetics. (c) 2007 Wiley Periodicals, Inc.