Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar 4710-057 Braga, Portugal.
Nutrients. 2020 Mar 31;12(4):967. doi: 10.3390/nu12040967.
Eudragit S100-coated chitosan microspheres (S100Ch) are proposed as a new oral delivery system for green tea polyphenon-60 (PP60). PP60 is a mixture of polyphenolic compounds, known for its active role in decreasing oxidative stress and metabolic risk factors involved in diabetes and in other chronic diseases. Chitosan-PP60 microspheres prepared by an emulsion cross-linking method were coated with Eudragit S100 to ensure the release of PP60 in the terminal ileum. Different core-coat ratios of Eudragit and chitosan were tested. Optimized chitosan microspheres were obtained with a chitosan:PP60 ratio of 8:1 (Ch-PP60), rotation speed of 1500 rpm, and surfactant concentration of 1.0% (/) achieving a mean size of 7.16 µm. Their coating with the enteric polymer (S100Ch-PP60) increased the mean size significantly (51.4 µm). The in vitro modified-release of PP60 from S100Ch-PP60 was confirmed in simulated gastrointestinal conditions. Mathematical fitting models were used to characterize the release mechanism showing that both Ch-PP60 and S100Ch-PP60 fitted the Korsmeyers-Peppas model. The antioxidant activity of PP60 was kept in glutaraldehyde-crosslinked chitosan microspheres before and after their coating, showing an IC of 212.3 µg/mL and 154.4 µg/mL, respectively. The potential of chitosan microspheres for the delivery of catechins was illustrated, with limited risk of cytotoxicity as shown in Caco-2 cell lines using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The beneficial effects of green tea and its derivatives in the management of metabolic disorders can be exploited using mucoadhesive chitosan microspheres coated with enteric polymers for colonic delivery.
Eudragit S100 包衣壳聚糖微球（S100Ch）被提议作为绿茶多酚 60（PP60）的新口服递药系统。PP60 是多酚类化合物的混合物，以其在降低氧化应激和代谢风险因素方面的积极作用而闻名，这些因素涉及糖尿病和其他慢性疾病。通过乳化交联法制备的壳聚糖-PP60 微球用 Eudragit S100 包衣，以确保 PP60 在回肠末端释放。测试了不同的核-壳比的 Eudragit 和壳聚糖。用壳聚糖：PP60 比为 8:1（Ch-PP60）、转速为 1500rpm 和表面活性剂浓度为 1.0%（/）获得优化的壳聚糖微球，平均粒径为 7.16 µm。用肠溶聚合物（S100Ch-PP60）对其进行包衣显著增加了平均粒径（51.4 µm）。在模拟胃肠道条件下证实了 S100Ch-PP60 中 PP60 的体外改性释放。使用数学拟合模型来表征释放机制，表明 Ch-PP60 和 S100Ch-PP60 均符合 Korsmeyers-Peppas 模型。戊二醛交联壳聚糖微球包衣前后 PP60 的抗氧化活性保持不变，分别为 IC50 为 212.3 µg/mL 和 154.4 µg/mL。壳聚糖微球对儿茶素传递的潜力表明，用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定法在 Caco-2 细胞系中显示出有限的细胞毒性风险。使用肠溶聚合物包衣的粘弹性壳聚糖微球可用于结肠递药，从而利用绿茶及其衍生物在代谢紊乱管理中的有益作用。
