聚乙二醇修饰的羟基喜树碱纳米脂质载体的制备及其小鼠组织分布

本研究采用熔融乳化-高压均质法制备了聚乙二醇(PEG)修饰的羟基喜树碱(HCPT)纳米脂质载体(HCPT-PEG-NLC)及非修饰的羟基喜树碱纳米脂质载体(HCPT-NLC)，并考察了其形态、粒径及包封率。测定了HCPT注射液、HCPT-PEG-NLC及HCPT-NLC 3种制剂经小鼠尾静脉注射后在血浆、心、肝、脾、肺、肾及卵巢等主要组织的浓度，评价了HCPT-PEG-NLC及HCPT-NLC在各组织的靶向性效果。透射电镜下观察，HCPT-PEG-NLC及HCPT-NLC呈球形；测得平均粒径分别为(88.6±22.5)和(127.2±43.4)nm；包封率分别为(90.51±3.29)%和(84.37±2.81)%。经小鼠尾静脉注射后，HCPT-PEG-NLC及HCPT-NLC在多数取样时间点的血药浓度较HCPT注射液有所提高，HCPT在各组织中的消除半衰期明显延长。HCPT-NLC蓄集于网状内皮系统(RES)，在肝、脾的相对摄取率(R_e)和峰浓度比(C_e)明显高于HCPT-PEG-NLC。HCPT-PEG-NLC延长了药物在血浆中的滞留时间，提高了生物利用度，MRT及AUC_{0-24 h}分别为注射液的19.80和17.02倍，并且与HCPT-NLC比较显著降低了RES的吞噬作用，在肺部表现出明显的靶向作用(R_e及C_e分别为14.51，41.35)。综上，HCPT-PEG-NLC可延长HCPT的体内循环时间，呈现明显的肺靶向性，有望作为HCPT肺癌治疗的理想载体。

Preparation of PEG-modified nanostructured lipid carriers loaded with hydroxycamptothecin and tissue distribution in mice

Hydroxycamptothecin (HCPT) loaded PEG modified nanostructured lipid carriers (HCPT-PEG-NLC) and nanostructured lipid carriers (HCPT-NLC) were prepared by melt emulsification and homogenization method. The morphology, particle size and encapsulation efficiency of them were investigated. HCPT concentrations in plasma, heart, liver, spleen, lung, kidney and ovary were determined after iv of HCPT injection, HCPT-PEG-NLC and HCPT-NLC in mice. The targeting indexes of HCPT-PEG-NLC and HCPT-NLC were calculated. The transmission electron microscope imaging showed that HCPT-PEG-NLC and HCPT-NLC exhibited a spherical shape. The particle sizes of them were (88.6 +/- 22.5) and (127.2 +/- 43.4) nm. The encapsulation efficiency were (90.51 +/- 3.29)% and (84.37 +/- 2.81)%, respectively. After iv injection into the tail vein of mice, HCPT plasma concentrations of HCPT-PEG-NLC and HCPT-NLC were higher than that of HCPT injection at each sampling time. They also showed longer elimination time in every tissue. HCPT-NLC accumulated in endothelial system (RES), Re and Ce of it in liver and spleen were significantly higher than HCPT-PEG-NLC. HPCT-PEG-NLC prolonged circulation time and increased bioavailability of HCPT. MRT and AUC0-24 h of it were 19.80 and 17.02 times higher than those of HCPT injection. It also significantly reduced phagocytosis of RES, and showed lung targeting effect (Re and Ce were 14.51 and 41.35). To summarize, HCPT-PEG-NLC could prolong the circulation time of HCPT in vivo, and had the lung targeting effect. It was a promising carrier to increase therapeutic effect of HCPT in treating lung cancer.