双配体修饰脂质聚合物杂化纳米粒的制备及细胞摄取研究

目的制备双修饰的主动心肌靶向的载荧光探针香豆素-6(C-6)的脂质-聚合物杂化纳米粒(LPHNs),并考察其细胞摄取。方法通过巯基化反应,合成导向化合物心肌细胞靶向肽-聚乙二醇-磷脂酰乙醇胺(PCM-PEG-DSPE)。选取C-6为荧光探针,采用自动组装法制备包载C-6的LPHNs,再通过插入法,用PCM和细胞穿膜肽(TAT)对C-6-LPHNs进行修饰。以心肌细胞(H9C2)为模型做体外细胞摄取实验。结果双修饰的C-6-LPHNs的平均粒径为74.5±4.2 nm,分散系数(PDI)为0.051±0.013,Zeta电位为-32.8±1.2 mV,包封率为87.04%±3.19%。双修饰的C-6-LPHNs对H9C2心肌细胞的摄取率明显高于未修饰的C-6-LPHNs。结论 LPHNs经双修饰后可促进H9C2心肌细胞的摄取。     

细胞外囊泡在肿瘤靶向治疗中的作用及应用

植物细胞、细菌细胞和哺乳动物细胞均可生成和分泌细胞外囊泡,囊泡内含有蛋白质、核酸、脂质和小分子代谢物。在发现早期,细胞外囊泡只被认为是细胞处置细胞废弃物的一种方式,后发现这些囊泡可在不同细胞之间传递活性物质并改变囊泡受体细胞表型。越来越多的研究证实囊泡是细胞间短程和长程通讯的一种新机制,是细胞间通讯的新范式。细胞外囊泡具有广泛的生理病理作用,既可直接用作药物也可作为药物递送载体,还可作为药物靶标和生物标志物。综述植物、细菌和哺乳动物等不同细胞来源的细胞外囊泡在肿瘤靶向治疗中的作用和应用及工程化策略。     

新型给药系统聚合物泡囊及其研究进展（上）

英国人Rymen于1971年发现由磷脂类和胆固醇的双分子层组成的脂质体,其膜具有类似生物膜结构,可以作为药物的优良载体,主要特点有靶向性、缓释性、细胞亲和性和组织相容性。脂质体存在的问题主要是不太稳定,包括药物易渗漏、磷脂易受氧化和降解等。近年发展成泡囊（niosomes）。聚合物泡囊作为药物载体与脂质体的结构极其相似,同脂质体一样具有组织相容性和细胞亲和性,但没有脂质体易受氧化或水解的缺点,粒径较小的泡囊可在有渗漏性血管的组织（如肿瘤或炎症区等）聚集,即增强滞留和透过（EPR）效应,粒径大的泡囊也可在肝、脾浓集,具有被动靶向作用。     

配体修饰聚合物胶束的研究进展

配体修饰的聚合物胶束除了具有一般聚合物胶柬所具有的稳定性好、载药范围广等优点外。还能主动靶向于特定的组织、器官,从而成为主动靶向制剂的载体。近年来。配体修饰的聚合物胶束得到了广泛的研究,研究结果显示其作为主动靶向制剂载体,具有良好开发和应用前景。本文就不同类型的配体(多肽、转铁蛋白、叶酸等)所修饰的聚合物胶束进行了分类综述。     

聚乙二醇修饰对羟喜树碱隐形纳米囊泡的肿瘤靶向和抑瘤作用的影响

目的探讨聚乙二醇相对分子质量对载羟喜树碱(HCPT)的聚乙二醇化聚十六烷基氰基丙烯酸酯纳米囊泡(PEG-PHDCA)在S180肉瘤小鼠体内的肿瘤靶向性及抗肿瘤作用的影响。方法选用司盘60和PEG-PHDCA为载体材料,制备HCPT的PEG-PHDCA隐形纳米囊泡,进行S180肉瘤小鼠瘤内药动学试验和抑瘤试验。结果PEG相对分子质量为2 000、5 000、10 000的PEG-PHDCA纳米囊泡在S180肉瘤小鼠肿瘤中125I-HCPT的AUC分别为HCPT的9.21、13.82、9.48倍;对S180肉瘤小鼠抑瘤率分别为88%、97.1%、80.8%,普通纳米粒PHDCA组抑瘤率为41.8,而原药组抑瘤率仅为17.3%。结论PEG修饰纳米囊泡明显优于原药和未经PEG修饰纳米囊泡,PEG相对分子质量为5 000,粒径为80 nm左右时,载HCPT的隐形纳米囊泡具有最佳肿瘤靶向作用。     

肺靶向卡铂泡囊冻干品的制备及特性研究

用薄膜分散法制备卡铂非离子表面活性剂泡囊,其球形圆整,大小较均匀,算术平均球径为3．72um,包封率为29．16％,pH值为6．34,体外释药符合双相动力学规律,释药t1/2比原药延长约10倍,于冰箱,室温和37℃（RH75％）考察3个月,几乎无变化。     

聚合物囊泡的稳定性及H+透膜特性考察

目的 以嵌段聚合物制备聚合物囊泡并考察其稳定性，测定聚合物囊泡膜层的H⁺跨膜渗透特性，及1,4-二氧六环对膜渗透性能的影响，作为聚合物囊泡载药的基础。方法 以二嵌段共聚物PEG-PLGA在溶液中自组装制备聚合物囊泡，采用pH敏感荧光探针HPTS对囊泡的H⁺透膜特性进行考察，并与PBD-b-PEO、PS-b-PEO制备的囊泡及脂质体进行比较。考察不同浓度的1,4-二氧六环对聚合物囊泡膜渗透特性的作用。结果 HPTS的荧光激发光谱有pH依赖性，囊泡外水相中H⁺浓度与t^1/2呈线性相关，不同膜壁厚度的聚合物囊泡的膜渗透能力有显著区别。3种聚合物囊泡对比脂质体，H⁺透膜系数分别降低了2.39×10⁴ 、3.38×10⁴、5.48×10⁸倍。1,4-二氧六环对囊泡膜的渗透性具有调节作用，且存在浓度依赖关系。结论 聚合物囊泡的膜渗透显著低于脂质体，稳定性更好，1,4-二氧六环可调节囊泡膜的渗透性，从而调节药物的装载和释放。     

肺靶向卡铂囊泡的研究

目的制备卡铂非离子型表面活性剂囊泡,以提高卡铂对肺癌的疗效并降低其毒副作用。方法用薄膜分散法制备卡铂囊泡,紫外分光光度法测定药物的含量,二阶导数法测定体外释药。小鼠体内分布试验,用iv.S-180肿瘤细胞建立了肺肿瘤模型,计算瘤结节数。结果卡铂囊泡平均粒径为3.72μm,最小粒径为2.0μm,最大粒径为10.0μm,跨距为0.66。卡铂囊泡包封率为29.2%。体外释药符合双指数方程的规律,释药T_1/2比原药延长9.14倍。体内分布研究表明,卡铂囊泡与原药相比,有明显的肺靶向性。卡铂泡囊对小鼠肺脏S-180肿瘤生长较原药的抑瘤作用有明显提高。结论卡铂囊泡在体内有良好的肺靶向性。     

RP-HPLC法测定康普瑞丁A4磷酸酯聚合物囊泡的含量

目的:建立康普瑞丁A4磷酸酯(CA4P)聚合物囊泡中CA4P的含量测定方法。方法 :采用反相高效液相色谱法。色谱柱为C18,流动相为乙腈-甲醇-0.02 mol/L乙酸铵(10∶40∶50),流速为1.0 ml/min,检测波长为288 nm。结果:CA4P检测质量浓度线性范围为2.1⁴2μg/ml(r=0.999 9),平均回收率为96.72%(RSD=1.61%,n=3),检测限与定量限分别为0.21、0.70μg/ml。结论:本方法简便、准确度好,可有效控制CA4P聚合物囊泡中CA4P的含量。     

聚焦超声联合微泡开放血脑屏障增强脑靶向递送研究进展

血脑屏障(blood-brain barrier, BBB)是药物脑靶向递送的最主要屏障,聚焦超声和微泡联合应用为跨BBB脑靶向递送提供了一种新途径,其主要机制为空化效应.本综述概括了近年来采用聚焦超声联合微泡增强BBB通透性实现药物脑靶向递送的相关研究,详细论述了聚焦超声及其作用机制;商品化微泡种类、常用微泡膜材、内...     

脑靶向鼻腔给药的研究进展

目的阐述鼻腔的生理特点和药物由鼻黏膜转运入脑的机制及其影响因素。方法依据近年来的29篇中外文文献,对药物的鼻腔脑靶向实验手段、离体在体模型、鼻黏膜的毒性等方面的研究进展进行阐述。结果鼻黏膜给药途径在脑内递药领域具有独特优势,其在脑部疾病治疗方面具有独到之处,值得进一步深入研究。结论药物的鼻腔脑靶向给药将受到越来越多的关注。     

Effect of a Chemical Delivery System for Dexamethasone (Dex-CDS) on Peritumoral Edema in an Experimental Brain Tumor Model

Pharmaceutical Research -     

Transport Across the Primate Blood-Brain Barrier of a Genetically Engineered Chimeric Monoclonal Antibody to the Human Insulin Receptor

Purpose. Brain drug targeting may be achieved by conjugating drugs,that normally do not cross the blood-brain barrier (BBB), to brain drugdelivery vectors. The murine 83-14 MAb to the human insulin receptor(HIR) is a potential brain drug targeting vector that could be used inhumans, if this MAb was genetically engineered to form a chimericantibody, where most of the immunogenic murine sequences arereplaced by human antibody sequence. Methods. The present studies describe the production of the gene forthe chimeric HIRMAb, expression and characterization of the protein,radiolabeling of the chimeric HIRMAb with 111-indium and125-iodine, and quantitative autoradiography of living primate brain taken 2hours after intravenous administration of the [¹¹¹In]chimeric HIRMAb. Results. The chimeric HIRMAb had identical affinity to the targetantigen as the murine HIRMAb based on Western blotting andimmunoradiometric assay using partially purified HIR affinity purified fromserum free conditioned media produced by a CHO cell line secretingsoluble HIR. The [¹²⁵I]chimeric HIRMAb was avidly bound to isolatedhuman brain capillaries, and this binding was blocked by the murineHIRMAb. The [¹¹¹In]chimeric HIRMAb was administeredintravenously to an anesthetized Rhesus monkey, and the 2 hour brain scanshowed robust uptake of the chimeric antibody by the living primatebrain. Conclusions. A genetically engineered chimeric HIRMAb has beenproduced, and the chimeric antibody has identical reactivity to thehuman and primate BBB HIR as the original murine antibody. Thischimeric HIRMAb may be used in humans for drug targeting throughthe BBB of neurodiagnostic or neurotherapeutic drugs that normallydo not cross the BBB.     

Effect of lactoferrin- and transferrin-conjugated polymersomes in brain targeting： in vitro and in vivo evaluations

Aim:

To evaluate the effect of lactoferrin (Lf) and transferrin (Tf) in brain targeting.

Methods:

Polymersomes (PSs), employed as vectors, were conjugated with Lf or Tf and were characterized by morphology, particle size, zeta potential, and surface densities of the Lf or Tf molecules. In vitro uptake of Lf-PS and Tf-PS by bEnd.3 cells was investigated using coumarin-6 as a fluorescent probe. In vivo tissue distribution and pharmacokinetics of ¹²⁵I-Lf-PS and ¹²⁵I-Tf-PS were also examined.

Results:

The mean particle size of PS, Lf-PS, and Tf-PS was around 150 nm and the zeta potential of the PSs was about -20 mV. Less than 0.12% of the coumarin was released from coumarin-6-loaded PS in 84 h indicating that coumarin-6 was an accurate probe for the PSs'' behavior in vitro. It was shown that the uptake of Lf-PS and Tf-PS by bEnd.3 cells was time-, temperature-, and concentration-dependent. Both Lf and Tf could increase the cell uptake of PSs at 37°C, but the uptake of Tf-PS was significantly greater than that of Lf-PS. In vivo tissue distribution and pharmacokinetics in mice revealed higher brain uptake and distribution of Tf-PS than Lf-PS, which was in accordance with in vitro uptake results. The drug targeting index (DTI) of Tf-PS with regard to Lf-PS was 1.51.

Conclusion:

Using a PS as the delivery vector and bEnd.3 cells as the model of the blood-brain barrier (BBB), Tf was more effective than Lf in brain targeting.     

基于营养转运体或信号受体介导的仿生递药策略在脑部肿瘤治疗中的应用进展

血脑屏障（BBB）限制了绝大多数药物进入脑部,从而成为中枢神经系统疾病治疗的主要障碍。基于仿生策略的脑部疾病靶向递药系统,是近年来极受研究者关注的具有广阔应用前景的药物递送系统。在脑部肿瘤病理环境中,BBB的血管上皮组织或肿瘤细胞高表达营养转运体及特定信号受体,以支撑肿瘤快速增殖的需要。综述近年来基于营养物质转运体及信号受体途径介导的脑部肿瘤仿生靶向递药研究进展。

     

Stereoselectivity of noradrenaline uptake into synaptic vesicles of the rat brain

Summary To investigate the stereoselectivity of the ATP-Mg²⁺-dependent uptake of noradrenaline, synaptic vesicles were isolated from the rat brain by differential centrifugation and incubated with ³H-(±)-, ³H-(–)- or ¹⁴C-(+)-noradrenaline in the absence and in the presence of ATP-Mg²⁺. The K _m values of the ATP-Mg²⁺-dependent uptake were found to be different for the two isomers (mol/l): ³H(±)-noradrenaline 14.9 ± 2.2 × 10^–1, ³H-(–)-noradrenaline 7.7 ± 0.5 × 10^–1, ¹⁴C-(+)-noradrenaline 17.3 ± 3.7 × 10^–1, whereas the V _maX of the racemate was identical with those of the two isomers (pmol/mg protein/min): ³H-(±)-noradrenaline 5.5 ± 0.4, ³H-(–)-noradrenaline 4.9 + 0.1, ¹⁴C-(+)-noradrenaline 5.1 ± 0.4. Moreover, (+)-noradrenaline inhibited competitively the ATP-Mg²⁺-dependent uptake of ³H-(±)-noradrenaline (K_i 19.2 + 1.0 × 10^–1 mol/l) and ³H-(–)-noradrenaline (Ki 17.7 ± 1.8 × 10^–1 mol/l), the K_i values being nearly identical with the K _m of the ATP-Mg²⁺-dependent uptake of ¹⁴C-(+)-noradrenaline. It is concluded that the ATP-Mg²⁺-dependent uptake of noradrenaline into synaptic vesicles of the rat brain is stereoselective and that both isomers share the same transport system.The experiments were carried out at the Institut für Pharmakologie and Toxikologie der Universitat Würzburg, FRG. This work was supported by the Deutsche Forschungsgemeinschaft Send offprint requests to A. Philippu at the above address     

Human serum albumin nanoparticles modified with apolipoprotein A-I cross the blood-brain barrier and enter the rodent brain

Nanoparticles made of human serum albumin (HSA) and modified with apolipoproteins have previously been shown to transport drugs, which normally do not enter the brain, across the blood-brain barrier (BBB). However the precise mechanism by which nanoparticles with different apolipoproteins on their surface can target to the brain, as yet, has not been totally elucidated. In the present study, HSA nanoparticles with covalently bound apolipoprotein A-I (Apo A-I) as a targetor for brain capillary endothelial cells were injected intravenously into SV 129 mice and Wistar rats. The rodents were sacrificed after 15 or 30?min, and their brains were examined by transmission electron microscopy. Apo A-I nanoparticles could be found inside the endothelial cells of brain capillaries as well as within parenchymal brain tissue of both, mice and rats, whereas control particles without Apo A-I on their surface did not cross the BBB during our experiments. The maintenance of tight junction integrity and barrier function during treatment with nanoparticles was demonstrated by perfusion with a fixative containing lanthanum nitrate as an electron dense marker for the permeability of tight junctions.     

The Effects of Clioquinol on P-glycoprotein Expression and Biometal Distribution in the Mouse Brain Microvasculature

Previous studies have demonstrated that the ionophore clioquinol (CQ), in conjunction with the biometals copper and zinc, increases the expression of P-glycoprotein (P-gp) in human cerebral microvascular endothelial (hCMEC/D3) cells. As P-gp expression and function at the blood-brain barrier (BBB) is of great interest regarding CNS drug access and endogenous toxin trafficking (e.g., amyloid beta), the present study assessed the in vivo translation of these previous in vitro findings. Swiss outbred mice received an 11-day treatment of CQ (30 mg/kg) by oral gavage, after which brain microvessel-enriched fractions (MEFs) and surrounding interfaces (subcortical brain tissue and plasma) were extracted. P-gp expression was quantified in the MEF, and biometal concentrations in all 3 compartments were assessed via inductively coupled plasma mass spectrometry. CQ treatment did not modify the expression of P-gp, nor copper or zinc concentrations in the brain MEF under this treatment regime. Metallomic analysis revealed, however, that CQ reduced potassium and magnesium levels in the brain MEF and also lowered brain iron levels. This study has shown that under this dosing regimen, CQ does not increase BBB P-gp expression in Swiss outbred mice, but that CQ facilitates redistribution of certain metal ions within the brain MEF, plasma, and brain parenchyma.     

Selective plasma pharmacokinetics and brain uptake in the mouse of enzyme fusion proteins derived from species-specific receptor-targeted antibodies

Enzymes may be re-engineered for brain drug targeting as an IgG-enzyme fusion protein, where the IgG is a monoclonal antibody (MAb) against an endogenous blood–brain barrier (BBB) receptor transporter, such as the insulin receptor or transferrin receptor (TfR). Iduronate 2-sulfatase (IDS) is fused to the heavy chain of a genetically engineered MAb against the human insulin receptor (HIR). Neither the HIRMAb alone, nor the HIRMAb–IDS fusion protein, is delivered across the BBB in the mouse, owing to lack of cross-reactivity of the HIRMAb with the insulin receptor in the mouse. The uptake of the HIRMAb–IDS fusion protein in peripheral organs exceeds that of the HIRMAb, which is attributed to uptake mediated via the mannose-6 phosphate receptor in non-brain organs. In contrast to the lack of BBB transport of the HIRMAb–IDS fusion protein, there is high BBB penetration in the mouse of an IDS fusion protein and a chimeric MAb against the mouse TfR. The comparison of the brain distribution of two different IgG-IDS fusion proteins, with different reactivity for an endogenous BBB receptor, illustrates the difference in brain targeting of a biopharmaceutical caused by the targeting properties of the IgG domain of the fusion protein.