Remuñán-López C, Lorenzo-Lamosa M L, Vila-Jato J L, Alonso M J
University of Santiago de Compostela, Spain.
Eur J Pharm Biopharm. 1998 Jan;45(1):49-56. doi: 10.1016/S0939-6411(97)00122-7.
Chitosan (CS) is a very interesting biomaterial for drug delivery; however its use in oral administration is restricted by its fast dissolution in the stomach and limited capacity for controlling the release of drugs. To address this limitation, a new microparticulate CS controlled release system, consisting of hydrophilic CS microcores entrapped in a hydrophobic cellulosic polymer, such as cellulose acetate butyrate (CAB) or ethyl cellulose (EC) was proposed. These microparticles were obtained with different types of CS and various core/coat ratios, with the particle size in all cases being smaller that 70 microns. Using sodium diclofenac (SD) and fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) as model compounds, the properties of these new microparticles for the entrapment and controlled release of drugs and proteins were investigated. Results showed that the entrapment efficiency of SD was very high irrespective of the processing conditions. Furthermore, for both model compounds (SD and FITC-BSA) it was possible to modulate the in vitro release of the encapsulated molecules by changing the core properties (CS salt, Mw, core/coat ratio) or the coating polymer. The microparticles were stable at low pH and thus, suitable for oral delivery without requiring any harmful cross-linkage treatment.
壳聚糖（CS）是一种非常有趣的用于药物递送的生物材料；然而，其在口服给药中的应用受到其在胃中快速溶解以及控制药物释放能力有限的限制。为了解决这一限制，提出了一种新的微粒型CS控释系统，该系统由包裹在疏水性纤维素聚合物（如醋酸丁酸纤维素（CAB）或乙基纤维素（EC））中的亲水性CS微核组成。这些微粒通过不同类型的CS和各种核/壳比例获得，所有情况下的粒径均小于70微米。以双氯芬酸钠（SD）和异硫氰酸荧光素标记的牛血清白蛋白（FITC-BSA）作为模型化合物，研究了这些新型微粒对药物和蛋白质的包封及控释性能。结果表明，无论加工条件如何，SD的包封效率都非常高。此外，对于两种模型化合物（SD和FITC-BSA），都可以通过改变核的性质（CS盐、分子量、核/壳比例）或包衣聚合物来调节包封分子的体外释放。这些微粒在低pH值下稳定，因此适合口服给药，无需任何有害的交联处理。
