壳聚糖在药物剂型中的应用

Application of chitosan in pharmaceutical dosage forms

壳聚糖来源丰富,具有良好的生物相容性、生物可降解性、无毒性、成膜性和极强的可塑性,已经作为高分子材料,广泛用于药物剂型中。利用壳聚糖制备的缓释制剂可以提高药物安全性、有效性及可靠性,可以调整药物释放速率,减少给药次数。壳聚糖及其衍生物是很好的靶向制剂载体,已被广泛应用于靶向给药系统的研究,可以有效提高药物在靶点的作用,减少给药量,避免药物在到达靶点前被降解,使药物在其他部位的毒副作用降低。壳聚糖作为药物载体虽然由其独特的优势,但在生产和应用上还有不少问题,目前常用戊二醛作为化学交联剂而制备壳聚糖微球,但是戊二醛对蛋白质等生物活性药物的伤害极大,并且对人体也有害,而用离子交联方法制备的微球极不稳定。因此,目前人们研究的重点在于对壳聚糖进行改性,进一步提高其载药能力。

Chitosan can be obtained in large quantities with many features such as biocompatibility, biodegradability, non-toxicity, film-forming and plasticity, thus it has been used extensively in pharmaceutical dosage forms as a new kind of natural biomaterial. The chitosan-based sustained-release preparations can not only improve safety, effectiveness and reliability of the encapsulated drugs but also modulate the drug release rate and decrease the administration frequency. Chitosan and its derivatives are good carders for targeted preparations, which have been used extensively in research on targeted drug delivery. These carriers can improve the effects of the drugs on targets, decrease dose and prevent the drugs from degradation before reaching targets, thus minimizing the side effects of the drugs on other sites. Chitosan has distinct advantages when used in drug delivery systems, however, many problems still exist in practice. At present, glutaraldehyde is the common used chemical cross linker in the preparation of chitosan microsphere However, glutaraldehyde has harmful effects on human beings and bioactive drugs such as protein. The microsphere prepared by ionic cross linking is unstable. Therefore, much attention has been paid on the modification of chitosan in order to increase the loading efficiency of the microsphere.