Liu Liyao, Zhou Cuiping, Xia Xuejun, Liu Yuling
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing Key Laboratory of Drug Delivery Technology and Novel Formulations, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China.
Int J Nanomedicine. 2016 Feb 24;11:761-9. doi: 10.2147/IJN.S96146. eCollection 2016.
Here, we investigated the formation and functional properties of self-assembled lecithin/chitosan nanoparticles (L/C NPs) loaded with insulin following insulin-phospholipid complex preparation, with the aim of developing a method for oral insulin delivery.
Using a modified solvent-injection method, insulin-loaded L/C NPs were obtained by combining insulin-phospholipid complexes with L/C NPs. The nanoparticle size distribution was determined by dynamic light scattering, and morphologies were analyzed by cryogenic transmission electron microscopy. Fourier transform infrared spectroscopy analysis was used to disclose the molecular mechanism of prepared insulin-loaded L/C NPs. Fast ultrafiltration and a reversed-phase high-performance liquid chromatography assay were used to separate free insulin from insulin entrapped in the L/C NPs, as well as to measure the insulin-entrapment and drug-loading efficiencies. The in vitro release profile was obtained, and in vivo hypoglycemic effects were evaluated in streptozotocin-induced diabetic rats.
Our results indicated that insulin-containing L/C NPs had a mean size of 180 nm, an insulin-entrapment efficiency of 94%, and an insulin-loading efficiency of 4.5%. Cryogenic transmission electron microscopy observations of insulin-loaded L/C NPs revealed multilamellar structures with a hollow core, encircled by several bilayers. In vitro analysis revealed that insulin release from L/C NPs depended on the L/C ratio. Insulin-loaded L/C NPs orally administered to streptozotocin-induced diabetic rats exerted a significant hypoglycemic effect. The relative pharmacological bioavailability following oral administration of L/C NPs was 6.01%.
With the aid of phospholipid-complexation techniques, some hydrophilic peptides, such as insulin, can be successfully entrapped into L/C NPs, which could improve oral bioavailability, time-dependent release, and therapeutic activity.
在此，我们研究了在制备胰岛素 - 磷脂复合物后，负载胰岛素的自组装卵磷脂/壳聚糖纳米颗粒（L/C NPs）的形成及其功能特性，旨在开发一种口服胰岛素递送方法。
采用改良的溶剂注射法，通过将胰岛素 - 磷脂复合物与L/C NPs结合来获得负载胰岛素的L/C NPs。通过动态光散射测定纳米颗粒的大小分布，并用低温透射电子显微镜分析其形态。利用傅里叶变换红外光谱分析来揭示所制备的负载胰岛素的L/C NPs的分子机制。采用快速超滤和反相高效液相色谱法将游离胰岛素与包封在L/C NPs中的胰岛素分离，同时测定胰岛素包封率和载药效率。获得体外释放曲线，并在链脲佐菌素诱导的糖尿病大鼠中评估体内降血糖作用。
我们的结果表明，含胰岛素的L/C NPs平均粒径为180 nm，胰岛素包封率为94%，载药效率为4.5%。对负载胰岛素的L/C NPs的低温透射电子显微镜观察显示出具有中空核心的多层结构，周围环绕着几层双层结构。体外分析表明，胰岛素从L/C NPs中的释放取决于L/C比例。给链脲佐菌素诱导的糖尿病大鼠口服负载胰岛素的L/C NPs产生了显著的降血糖作用。口服L/C NPs后的相对药理生物利用度为6.01%。
借助磷脂复合技术，一些亲水性肽，如胰岛素，可以成功地包封到L/C NPs中，这可以提高口服生物利用度、时间依赖性释放和治疗活性。
