Department of Chemistry and Kanbar Laboratory for Nanomaterials, Bar-Ilan University Center for Advanced Materials and Nanotechnology, Bar-Ilan University, Ramat-Gan 52900, Israel.
Chemistry. 2010 Jan 11;16(2):562-7. doi: 10.1002/chem.200901464.
Chitosan is a biodegradable natural polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density, nontoxicity, and mucoadhesion properties. Processing techniques for the preparation of chitosan microspheres have been extensively developed since the 1980s. The present paper describes for the first time a fast and one-step process for the preparation of stable chitosan microspheres by a simple sonochemical method. The microspheres were characterized by their particle size, surface morphology, stability, and drug-entrapment efficiency. The average size of the microspheres was found to be around 1 mum with a narrow size distribution, which enabled them to be used for in vivo applications. The encapsulation of different dyes into these microspheres was readily achieved with more than 75 % efficacy by dissolving them into the organic phase before sonication. The chitosan microspheres demonstrated excellent stability toward acidic and basic conditions ranging from pH 4 to 9, thereby indicating their implementation as possible therapeutic and diagnostic agents. The stability of these microspheres appears to be contributed from intermolecular imine cross-linking in addition to other noncovalent interactions. The ability of the surface-exposed amino groups of chitosan microspheres to undergo chemical conjugation with potential drugs and/or targeting vectors was determined by their reaction with fluorescein isothiocyanate (FITC) and fluorescamine followed by confocal microscopy.
壳聚糖是一种可生物降解的天然聚合物，由于其生物相容性、高电荷密度、无毒性和黏膜黏附特性，在药物应用方面具有巨大的潜力。自 20 世纪 80 年代以来，壳聚糖微球的制备加工技术得到了广泛的发展。本文首次描述了一种通过简单的超声化学方法制备稳定壳聚糖微球的快速一步法。通过粒径、表面形貌、稳定性和药物包封效率对微球进行了表征。发现微球的平均粒径约为 1 微米，粒径分布较窄，可用于体内应用。通过在超声前将不同染料溶解在有机相中，很容易将这些微球包封，包封效率超过 75%。壳聚糖微球在 pH 值为 4 至 9 的酸性和碱性条件下表现出优异的稳定性，这表明它们可作为潜在的治疗和诊断剂。这些微球的稳定性似乎是由于分子间亚胺交联以及其他非共价相互作用所致。壳聚糖微球表面暴露的氨基与潜在药物和/或靶向载体发生化学偶联的能力通过其与异硫氰酸荧光素（FITC）和荧光胺的反应以及共聚焦显微镜来确定。
