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目的 为改善依托泊苷(VP-16)水溶性差和活性较低的问题,将VP-16制备成纳米颗粒(NP)悬浊液(VP-16 NP),以提高其对肿瘤细胞的杀伤作用,并通过体外血脑屏障(BBB)模型评价其穿透性.方法 利用反溶液交换法将VP-16制备为VP-16 NP,扫描电镜(SEM)观察形态,透射电镜(TEM)观察内部结构,动态光散射(DLS)测定粒径大小.通过测定VP-16粉末和VP-16 NP的药物释放曲线比较两者的释放率.采用MTT比色法检测VP-16 NP对KB细胞存活的影响.采用2周龄SD大鼠的第1~2代原代脑微血管内皮细胞构建体外BBB模型.依据经典的4 h渗漏实验、跨内皮电阻(TEER)实验和荧光素钠(FLU)穿透性实验,验证体外BBB模型,评价VP-16 NP的BBB穿透性.结果 TEM,SEM和DLS观察可见,制备的VP-16 NP为实心结构的球形,粒径约为140 nm.药物释放曲线结果显示,VP-16 NP的药物累积释放率是VP-16粉末的3倍.MTT比色法检测结果表明,VP-16粉末对KB细胞存活无抑制作用,而VP-16 NP能有效地抑制KB细胞存活.4 h渗漏实验中,Transwell细胞模型上室与下室能维持>0.5 cm的液面差,说明体外BBB模型初步形成.TEER实验有效电阻值为223 Ω·cm2,表明体外BBB模型基本建成.FLU穿透性实验结果显示,在15,30和60 min时,穿透系数分别为(0.33±0.04)×10-3,(0.42±0.07)×10-3和(0.52± 0.06)×10-3cm·min-1,说明模型的通透性低.体外BBB模型VP-16 NP穿透性结果显示,其在30 min的穿透系数为(1.87±0.03)×10-3cm·min-1,显示出较高的穿透性,表明VP-16 NP对BBB有较好的穿透效果.结论 VP-16 NP可提高药物的释放率,并有较好的BBB穿透性.“,”OBJECTIVE To improve the poor water solubility and evaluating poor acitivity of etoposide (VP-16) by preparing VP-16 nanoparticle suspension (VP-16 NP) and its penetration through the blood-brain barrier (BBB).METHODS VP-16 NP was prepared with the anti-solution exchange method.The shape structure and diameter were observed with transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and dynamic light scattering (DLS), respectively. The drug release profiles of the VP-16 powder and VP-16 NP were measured.The effect of VP-16 NP on the growth of KB cells was observed via MTT assay. In addition, primary brain microvascular endothelial cells from 1stto 2nd generation of SD rats at two weeks of age were used to construct an in vitro BBB model.The classic 4 h leak test,trans-epithelial electrical resistance (TEER) test and fluorescein disodium salt(FLU)perme?ability test were conducted to verify whether the in vitro BBB model was successfully established.RESULTS VP-16 NP was a solid sphere with a size of 140 nm detected by TEM,SEM and DLS.The cumulative release rate of VP-16 NP was 3 times that of VP-16 powder. The results of MTT colorimetric assay showed that VP-16 powder had no inhibitory effect on KB cells,while VP-16 NP could effectively inhibit KB cells. In the 4 h leakage experiment, the top and bottom chambers of the Transwell cell model could maintain a liquid surface distance of >0.5 cm,indicating that the in vitro BBB model was initially formed.The effective resistance value of the TEER experiment was 223 Ω·cm2,indicating that the in vitro BBB model was basically established. In FLU permeability experiments, the permeability coefficients were respectively (0.33±0.04)×10-3,(0.42±0.07)×10-3,and (0.52±0.06)×10-3cm·min-1at 15,30 and 60 min, indicating that the model had low permeability.The above three experiments suggested that the BBB in vitro model was successfully constructed. On this basis, the in vitro BBB model was used to evaluate the penetration of VP-16 NP at a permeability coefficient of (1.87±0.03)×10-3cm·min-1at 30 min,showing high permeability.VP-16 NP showed better penetration of BBB.CONCLUSION VP-16 NP is success?fully prepared,which increases the release rate of the drug,enhances the killing effect of the cells,and shows good penetration through the in vitro BBB model evaluation.