脂蟾毒配基PLGA-TPGS纳米粒在小鼠体内肝的靶向性

Hepatic targeting properties of Resibufogenin-loaded PLGA-TPGS nanoparticles in mice

目的:研究脂蟾毒配基(Resibufogenin,RBG)/香豆素-6(Coumarin-6,C6)乙交酯丙交酯共聚物-维生素E聚乙二醇1000琥珀酸酯(PLGA-TPGS)纳米粒(RBG/C6-loaded PLGA-TPGS nanoparticles,RCPTN)在小鼠体内的分布及对小鼠肝脏的靶向性。方法:建立RP-HPLC法测定RBG在小鼠血浆及肝、心、脾、肺和肾等生物样品中的浓度,将RCPTN和RBG溶液(RS)经小鼠尾静脉注射后,测定不同给药时间后小鼠血浆及各脏器中的RBG浓度。采用靶向指数(TI)、选择性指数(SI)、相对靶向效率(Re)和靶向效率(Te)4个指标,同时通过对各器官进行冰冻切片,荧光倒置显微镜下观察荧光纳米粒RCPTN在各器官的分布,定性、定量的全面评价RCPTN对肝脏的靶向性。结果:除SI血浆在0.08,0.5 h时,TI和SI的数值均大于1,表明RCPTN在各时间点对肝脏的靶向作用良好;在血浆、肝、心、脾、肺、肾中的Re分别为2.1、40.1、1.1、16.4、11.7、1.4,即在整个考察时间范围内,RCPTN在肝脏中的药时曲线下面积(AUC)是RS的40.1倍,表明载药纳米粒能将药物更好的传递至肝脏;RCPTN在血浆、心、脾、肺、肾中的Te均大于3,表明RBG在肝脏比血浆和其他脏器匀浆中的AUC高达3倍以上,且在心脏中的Te(28.1)是RS在心脏中Te(0.8)的35.1倍,表明RCPTN具有良好的肝脏靶向作用,且可显著降低RBG在心脏中的分布。冰冻切片图可见在1 h的RCPTN组小鼠各器官中,肝中荧光分布面积最大,其次是脾和肺,最后是肾和心。表明RCPTN静脉注射后对肝脏有良好的靶向性,这与用TI、SI、Re和Te 4个靶向指标评价RCPTN对肝脏的靶向性结果是一致的。结论:RCPTN对小鼠肝脏有良好的靶向作用,在心脏分布较少。

OBJECTIVE To study the distribution and liver targeting properties of Resibufogenin （RBG）-loaded polylactide-co-glycolide -D-α-tocopherol polyethylene glycol 1000 succinate nanoparticles （RPTN） in mice.METHODS To determine the concentration of RBG in biological samples, reverse phase-high performance liquid chromatography （RP-HPLC） method was set up. After intravenous administration to mice in RCPTN and RS groups, concentration of RBG in plasma and different organs were simultaneously analyzed at the different timepoints. Detection indexes （targeting index, selective index, relative targeting efficiency, targeting efficiency, namely TI, SI, Re and Te） and fluorescence inversion microscopy images of the organs （liver, heart, spleen, lungs and kidneys） frozen slices were used for evaluating liver targeting properties of RCPTN quantitatively and qualitatively in mice.RESULTS The concentration of RBG in plasma and different organs were analyzed by RP-HPLC method. Detection indexes （TI, SI, Re and Te） were used for evaluating liver targeting properties of RCPTN in mice：TI and SI were both greater than 1 at the different timepoints except SIplasma for 0.08 h and 0.5 h, which indicated good properties of RCPTN in liver targeting; in the plasma, liver, heart, spleen, lungs and kidneys, Re was 2.1, 40.1, 1.1, 16.4, 11.7, 1.4, respectively, indicating that area under the concentration-time curve （AUC） of RCPTN in liver was 40.1 times than that of RS, this showed that RBG could be delivered efficiently to the liver by RCPTN. Te of RCPTN group in the plasma, liver, heart, spleen, lungs and kidneys were all greater than 3, indicating that AUC of liver was more than three times of AUC of plasma and other organs, while Te of RCPTN in heart was 35.1 times than that of RS, demonstrating the excellent properties of RCPTN in liver targeting and RCPTN could significantly reduce the distribution of RBG in the heart. Fluorescence inversion microscopy images showed that green fluorescence of RCPTN mostly gathered in liver, followed by lungs and spleen, the last being heart and kidneys, which was coincident to detection indexes of drug concentration and further proved that active liver targeting properties of RCPTN was excellent in mice.CONCLUSION RCPTN had better liver targeting properties in vivo for the mice, and the concentration of RBG in heart of mice is lower.