Multicompartment systems: A putative carrier for combined drug delivery and targeting

In this review, we discuss recent developments in multicompartment systems commonly referred to as vesosomes, as well as their method of preparation, surface modifications, and clinical potential. Vesosomal systems are able to entrap more than one drug moiety and can be customized for site-specific delivery. We focus in particular on the possible reticuloendothelial system (RES) – mediated accumulation of vesosomes, and their application in tumor targeting, as areas for further investigation.     

RPV‐modified epirubicin and dioscin co‐delivery liposomes suppress non‐small cell lung cancer growth by limiting nutrition supply

Chemotherapy for non‐small cell lung cancer (NSCLC) is far from satisfactory, mainly due to poor targeting of antitumor drugs and self‐adaptations of the tumors. Angiogenesis, vasculogenic mimicry (VM) channels, migration, and invasion are the main ways for tumors to obtain nutrition. Herein, RPV‐modified epirubicin and dioscin co‐delivery liposomes were successfully prepared. These liposomes showed ideal physicochemical properties, enhanced tumor targeting and accumulation in tumor sites, and inhibited VM channel formation, tumor angiogenesis, migration and invasion. The liposomes also downregulated VM‐related and angiogenesis‐related proteins in vitro. Furthermore, when tested in vivo, the targeted co‐delivery liposomes increased selective accumulation of drugs in tumor sites and showed extended stability in blood circulation. In conclusion, RPV‐modified epirubicin and dioscin co‐delivery liposomes showed strong antitumor efficacy in vivo and could thus be considered a promising strategy for NSCLC treatment.     

星点设计-效应面法优化pH值响应及线粒体靶向双功能金丝桃苷脂质体的处方及其体外评价

目的 优化线粒体靶向金丝桃苷脂质体（DLD/Hyp-Lip）制备的最佳处方，并研究研究其在胎牛血清中的稳定性及体外释放行为，考察其线粒体靶向性。方法 采用薄膜分散法制备DLD/Hyp-Lip，以包封率和载药量为考察指标进行单因素实验，考察磷脂总量与金丝桃苷（hyperoside，Hyp）用量比、二硬脂酰磷脂酰乙醇胺-聚乙二醇（DSPE-PEG）与DLD用量比等条件对DLD/Hyp-Lip的影响，结合星点设计-效应面法优化DLD/Hyp-Lip处方。使用透射电子显微镜和粒径仪观察测定脂质体粒子外观、平均粒径和Zeta电位，采用血清稳定性实验和体外释药、线粒体靶向性对该载药系统进行评价。结果 DLD/Hyp-Lip最佳处方为磷脂总量和金丝桃苷用量比为12.50：1，磷脂总量与胆固醇用量比为6.00：1，DSPE-PEG与DLD用量比为3：5；测得金丝桃苷包封率为（95.57±0.56）%，载药量为（8.55±0.57）%。所制备的DLD/Hyp-Lip外观良好，平均粒径为（124.9±3.4）nm，Zeta电位为（-6.2±1.9）mV；在胎牛血清中性状稳定，在体外释放介质中24 h累积释放量达到40%。线粒体靶向实验表明DLD/Hyp-Lip可以促进药物聚集在线粒体部位。结论 采用此方法能够精准有效的优化DLD/Hyp-Lip的制备工艺，该方法操作简单方便，可以用于DLD/Hyp-Lip制备与处方的优化，制备的DLD/Hyp-Lip包封率高，粒径小，分布均匀，且具有良好的缓释作用，为DLD/Hyp-Lip的进一步体内研究奠定了基础。载金丝桃苷的DLD/Hyp-Lip具有良好的肝癌细胞线粒体靶向性，是一种潜在高效的肝癌细胞线粒体靶向给药系统。     

载As2O3 pH敏感钙砷复合物脂质体的制备及体外评价

目的 制备pH敏感释药的As₂O₃脂质体，并进行体外评价。方法 采用薄膜分散法制备含钙离子脂质体，然后用离子沉淀法孵育制备钙砷复合物脂质体（CaAs-LP）。测定CaAs-LP的粒径、Zeta电位及多分散系数（PDI）；透射电子显微镜观察脂质体的形态；电感耦合等离子体发射光谱仪测定纳米药物的载药量与包封率；透析袋法考察其体外释药特性。噻唑蓝（MTT）法考察未载药脂质体及CaAs-LP对人源性乳腺癌MCF-7细胞、人源性脑胶质瘤U87细胞和人源性肝癌HepG2细胞的毒性；共聚焦显微镜考察U87细胞对CaAs-LP的摄取效率。结果 制备的CaAs-LP呈规整类球型，粒径约为（117.16±1.94）nm，包封率和载药量分别为（74.31±2.11）%、（8.31±0.13）%。体外释放研究表明，CaAs-LP具有明显的缓释以及pH响应释药特征。未载药的脂质体在MCF-7、U87、HepG2和L02细胞中的生物相容性良好；CaAs-LP抑制肿瘤细胞生长的作用较原药有所上升，半数抑制浓度（IC₅₀）值分别为11.91、4.90、19.41、27.59 μmol/L。细胞摄取研究表明肝癌细胞对脂质体具有良好的摄取。结论 CaAs-LP具备显著的缓释以及pH响应释药的特性，在肿瘤治疗方面具有较好的应用前景。     

脂质体辅助递送CTLA-4 siRNA通过激活系统性抗肿瘤免疫反应抑制肾细胞癌生长

目的:探索携带CTLA-4 siRNA的适配子偶联脂质体颗粒是否可以激活肿瘤部位的抗肿瘤免疫反应，抑制肾细胞癌的生长。方法:采用薄膜水化法制备脂质体；使用透射电子显微镜观察脂质体的形态和结构；用Zetasizer测量Zeta电位；共孵育实验观察靶细胞对Lipo-siRNA的摄取；qPCR检测Lipo-siRNA对CTLA-4基因的沉默；小鼠移植瘤模型检测Lipo-siRNA的体内抑瘤能力；流式细胞术检测肿瘤浸润T细胞的激活状态；免疫荧光法检测肿瘤浸润T细胞的数目。结果:成功制备Lipo-siRNA，电镜结果显示其具有双层球状结构；Zetasizer测得其Zeta电位为(+20.53±2.66)mV；荧光显微镜观察结果表明Lipo-siRNA可以被靶细胞有效摄取，qPCR检测Lipo-siRNA可以显著降低CTLA-4基因的表达（P＜0.001）；小鼠移植瘤模型显示Lipo-siRNA较对照组而言可以显著抑制肿瘤生长（P＜0.001），降低肿瘤细胞中CTLA-4的表达（P＜0.001），提升肿瘤浸润T细胞的数量（P＜0.000 1），并且提高了肿瘤浸润T细胞中IL-2（P＜0.000 1）和IFN-γ（P＜0.000 1）的表达水平。结论:适配子偶联脂质体可以携带CTLA-4 siRNA靶向肿瘤细胞，激活肿瘤部位的抗肿瘤免疫反应，抑制肿瘤的生长，对肾细胞癌的治疗具有潜在的临床应用价值。     

Determination of Nonspherical Morphology of Doxorubicin-Loaded Liposomes by Atomic Force Microscopy

The 3-D morphology of doxorubicin (DOX)–loaded liposomes with a size of circa 100 nm was characterized by atomic force microscopy in an aqueous environment. Prolate liposomes appear in accordance with linear expansion of DOX fiber bundles precipitated inside liposomes. Oblate and concave liposomes were simultaneously observed with increased DOX concentrations; however, their morphologies were not readily determined by 2-D cryo-TEM imaging. Precise data analysis of the 3-D parameters of each liposome allowed semiquantitative evaluation of the transformation of spherical liposomes into nonspherical—prolate, oblate, and concave liposomes. In addition, nonspherical liposomes became spherical on the replacement of the liposomal outer phase consisting of a sucrose solution, with water and subsequent water influx. All spherical liposomes transformed into oblate and concave liposomes with a return to hyperosmotic conditions, when transferred from water to sucrose solution. Furthermore, the concave liposomes did not appear under DOX incubation conditions (65°C), which could be due to the amorphous and supersaturated DOX inside the liposomes that restrained liposomal shrinkage. As atomic force microscopy has improved our ability to image 3-D morphologies of liposomes in various conditions, it is an alternative analytical tool to cryo-TEM and may have future applications in regulatory tests for quality control and assurance.     

Formulation Development,Optimization, and In Vitro–In Vivo Characterization of Natamycin-Loaded PEGylated Nano-Lipid Carriers for Ocular Applications

The present study aimed at formulating and optimizing natamycin (NT)-loaded polyethylene glycosylated nano-lipid carriers (NT-PEG-NLCs) using Box-Behnken design and investigating their potential in ocular applications. Response surface methodology computations and plots for optimization were performed using Design-Expert^® software to obtain optimum values for response variables based on the criteria of desirability. Optimized NT-PEG-NLCs had predicted values for the dependent variables which are not significantly different from the experimental values. NT-PEG-NLCs were characterized for their physicochemical parameters; NT's rate of permeation and flux across rabbit cornea was evaluated, in vitro, and ocular tissue distribution was assessed in rabbits, in vivo. NT-PEG-NLCs were found to have optimum particle size (<300 nm), narrow polydispersity index, and high NT entrapment and NT content. In vitro transcorneal permeability and flux of NT from NT-PEG-NLCs was significantly higher than that of Natacyn^®. NT-PEG-NLC (0.3%) showed improved delivery of NT across the intact cornea and provided concentrations statistically similar to the marketed suspension (5%) in inner ocular tissues, in vivo, indicating that it could be a potential alternative to the conventional suspension during the course of fungal keratitis therapy.     

Cationic liposome co-encapsulation of SMAC mimetic and zVAD using a novel lipid bilayer fusion loaded with MLKL-pDNA for tumour inhibition in vivo

The increase in multidrug resistance among colon cancer cells presents a challenge for the development of effective therapies. Small-molecule analogues of second mitochondria-derived activator of caspase (SMAC) mimetic in association with mixed lineage kinase domain-like protein (MLKL)-pDNA and z-VAD-fmk have shown ideal antitumor effects in colon cancer cells in vitro via induction of RIP3-dependent necroptosis. To achieve synergistic antitumor effects in vivo, liposomes loaded with SMAC mimetic, MLKL-pDNA and z-VAD-fmk have been developed using novel lipid fusion methods to co-localise the molecules of interest within the tumour cells. The co-encapsulation liposome (MLKL-zVAD-BV6-LP) had a high entrapment efficiency of approximately 95% for both zVAD and BV6 and was able to condense MLKL-pDNA very well. The vectors showed good biocompatibility, tumour targeting and small-molecule co-localisation. In a CT26 mouse model, the MLKL-zVAD-BV6-LP exhibited a tumour-suppression rate of over 60% in vivo, which was significantly higher than that of both the null-liposome and coadministration groups. Above all, the co-encapsulation system provided a novel approach to combination tumour therapy.     

Hybrid liposomes showing enhanced accumulation in tumors as theranostic agents in the orthotopic graft model mouse of colorectal cancer

Hybrid liposomes (HLs) can be prepared by simply sonicating a mixture of vesicular and micellar molecules in a buffer solution. This study aimed to elucidate the therapeutic effects and ability of HLs to detect (diagnosis) cancer in an orthotopic graft mouse model of colorectal cancer with HCT116 cells for the use of HLs as theranostic agents. In the absence of a chemotherapeutic drug, HLs exhibited therapeutic effects by inhibiting the growth of HCT116 colorectal cancer cells in vitro, possibly through an increase in apoptosis. Intravenously administered HLs also caused a remarkable reduction in the relative cecum weight in an orthotopic graft mouse model of colorectal cancer. A decrease in tumor size in the cecal sections was confirmed by histological analysis using HE staining. TUNEL staining indicated an induction of apoptosis in HCT116 cells in the orthotopic graft mouse model of colorectal cancer. For the detection (diagnosis) of colorectal cancer by HLs, the accumulation of HLs encapsulating a fluorescent probe (ICG) was observed in HCT116 cells in the in vivo colorectal cancer model following intravenous administration. These data indicate that HLs can accumulate in tumor cells in the cecum of the orthotopic graft mouse model of colorectal cancer for a prolonged period of time, and inhibit the growth of HCT116 cells.