两种RGD肽修饰的新型阿霉素脂质体的体外表征

目的作为配体,肽对于多种受体显示出良好的靶向性,例如在肿瘤表面过度表达的整合素家族受体。本文主要研究和表征分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的载药脂质体。方法分别采用RGD和GRGDS对包载阿霉素的立体稳定脂质体(SSL-doxorubicin)进行修饰,以制备RGD-SSL-doxorubicin和GRGDS-SSL-doxorubicin。在体外表征试验中,测定了各种脂质体的包封率、粒径、Zeta电位和释放率,采用SRB试验研究了各脂质体对卵巢癌细胞的细胞毒作用,并应用流式细胞仪和共聚焦显微镜考察了肿瘤细胞对各脂质体包封的阿霉素的摄取情况。结果所有脂质体的包封率均在95%以上,采用RGD或GRGDS进行的修饰并未影响长循环脂质体的包封率。各种脂质体的平均粒径在105.7±3.5nm和130.5±3.0nm之间,Zeta电位在–3.3±0.3和–6.1±0.3mV之间,在模仿体内环境的释放介质(含胎牛血清)中,12小时内约有2/5的阿霉素从脂质体中释放。与游离阿霉素相比,修饰后的脂质体对肿瘤细胞的抑制率略有下降;在研究对阿霉素摄取的流式细胞试验和共聚焦试验中,也有类似现象出现。将各种脂质体分别加入肿瘤细胞后,阿霉素主要分布于SKOV-3的细胞核。结论本研究成功制备了两种分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的阿霉素脂质体。体外表征结果显示,该修饰不会显著改变立体稳定脂质体的性质。     

紫杉醇脂质体制备及体外抑制两种细胞的作用

目的:制备紫杉醇脂质体并考察体外对人卵巢癌上皮细胞(SKOV-3)和人脐静脉内皮细胞(HUVEC)两种细胞的抑制作用。方法:采用薄膜分散法制备紫杉醇脂质体,透射电镜观察脂质体的形貌,激光粒度仪测量粒径和Zeta电位,MTT法检测脂质体体外对SKOV-3和HUVEC的抑制作用。结果:制备的脂质体呈圆形或类圆形,平均粒径为54.6 nm,Zeta电位为-40.9 mv,体外释放符合Higuchi方程。体外细胞结果实验显示,紫杉醇能同时抑制肿瘤细胞和血管内皮细胞的生长。结论:紫杉醇脂质体较紫杉醇注射液(TAXOL)能更有效的抑制SKOV-3和HUVEC的生长。     

两亲性壳聚糖包覆紫杉醇脂质体的制备及体外释放研究

目的:制备两亲性壳聚糖N-辛基-N,O-羧甲基壳聚糖包覆紫杉醇脂质体(PTX-LP-OCC),并考察其理化性质及体外释放行为。方法:采用基于乙醇的前体脂质体法制备紫杉醇脂质体并以OCC包覆,并以普通脂质体(PTX-LP)为对照,测定其包封率、粒径大小、电位,观测其形态及稳定性,然后采用全体液平衡反向透析法研究体外释放行为。结果:紫杉醇脂质体包封率为89.5%,粒径为236.5 nm,Zeta电位为-31.4 mV,多糖包覆修饰后药物包封率无显著变化,粒径及Zeta电位显著增加,脂质体稳定性显著提高,药物释放呈缓释特征,且突释显著降低。结论:两亲性壳聚糖包覆脂质体是一个有前景的抗肿瘤药物递送载体     

脒修饰的包载荧光探针香豆素-6脂质体的制备

目的研究3,5-二-十五烷氧基苯甲脒(DBH)修饰的香豆素-6脂质体的制备工艺,并初步考察该脂质体的体外释放性能和肾小球靶向性。方法首先合成DBH。再以其为配基,胆固醇、大豆磷脂为载体材料,采用薄膜分散-超声法制备脒修饰的载香豆素-6荧光探针脂质体,考察其粒径分布、Zeta电位、包封率及体外累积释药率。结果脒基修饰的香豆素-6脂质体形态圆整,粒径分布为120.7±2.4 nm,Zeta电位为12.6±1.6 m V,包封率为99.7%±1.8%,体外的48 h累积释药量小于2%。结论脒基修饰的香豆素-6脂质体的制备工艺简便易操作,包封率高,性质稳定。     

甘草次酸修饰的阿霉素靶向脂质体的制备及体外抑瘤活性考察

目的：制备甘草次酸（GA）靶向阿霉素脂质体（GA-DOX-Lip）,并初步考察其体外抑瘤活性。方法：采用硫酸铵梯度载药法制备GA-DOX-Lip,单因素考察其处方工艺;采用微柱离心法和粒径仪考察脂质体包封率及其理化性质;通过荧光显微镜和流式细胞仪考察BEL-7402肝癌细胞对脂质体的摄取情况并用MTT法评价其体外杀伤效果。结果：GA-DOX-Lip形态圆整,粒径约为120 nm,包封率达到95%以上,72 h释放约20%;体外细胞摄取量和细胞杀伤效果均显著高于阿霉素普通脂质体。结论：甘草次酸修饰的脂质体有望成为肝肿瘤靶向的新型载体,促进抗肿瘤药物向肿瘤细胞内的递送。     

肺靶向吡非尼酮脂质体的制备及体外释药性质研究

目的：研究肺靶向吡非尼酮脂质体的制备方法并考察其体外释药性质。方法：采用薄膜分散法制备吡非尼酮脂质体;用D-甘露糖修饰脂质体并添加适量十八胺调节脂质体表面电荷;用紫外分光光度法测定包封率;用正交实验优化处方,用透析法考察药物体外释放性质。结果：制得的脂质体平均粒径为581.1nm,表面电荷为-20.61mV,包封率为81.1%,稳定性好。药物体外释药符合Weibull方程。结论：采用薄膜分散法,用D-甘露糖修饰并添加十八胺可制得具有较高包封率及稳定性的吡非尼酮脂质体,有助于提高吡非尼酮的肺靶向性。     

紫杉醇长循环热敏前体脂质体的制备与表征

目的:研究紫杉醇长循环热敏前体脂质体的制备并对其性质进行考察.方法:采用薄膜分散法制备紫杉醇长循环热敏脂质体,再用冷冻干燥技术制备紫杉醇长循环热敏前体脂质体;采用激光粒度仪考察粒径和Zeta电位;采用高效液相色谱法研究其含量与包封率;并考察脂质体的体外释药特性.结果:紫杉醇长循环热敏前体脂质体水合后形成紫杉醇长循环热敏脂质体,粒径均值为(108.6 ±3.6)nm,Zeta电位的均值为(-12.2±1.8)mV,包封率可达96.2％;该脂质体在相变温度42℃下药物释放达到95％以上.结论:紫杉醇长循环热敏前体脂质体的制备工艺稳定,载药量大,包封率高,具有良好的热敏性;含量及其包封率测定方法简单、快速、准确.本实验可为紫杉醇静脉注射用新制剂的开发提供研究基础.     

甘草次酸修饰多西紫杉醇脂质体的制备和体外抑瘤效果

目的:制备甘草次酸(GA)修饰的多西紫杉醇脂质体,并初步考察其体外抗肿瘤效果.方法:化学合成甘珀酸十八醇酯(18-GA-Suc)作为修饰材料,采用薄膜分散法制备甘草次酸修饰的多西紫杉醇脂质体,考察影响脂质体包封率的因素.采用MTT法评价脂质体对HepG2细胞的体外抑瘤效果.结果:18-GA-Suc修饰的DX脂质体的体外抑瘤效果强于未修饰的DX脂质体,并且抑瘤效果随着载体中18-GA-Suc的增加而增强.结论:甘草次酸修饰的脂质体有望成为新型肝靶向的抗肿瘤载体.     

叶酸壳寡糖修饰的紫杉醇PLGA纳米粒的体外释放及对SKOV-3增殖的抑制作用

摘 要 目的： 制备叶酸壳寡糖修饰的紫杉醇PLGA纳米粒（F-CS-PLGA-NPs）,并考察其对人卵巢癌上皮细胞（SKOV-3）的抑制作用。方法: 采用界面沉积法制备F-CS-PLGA-NPs,以30%乙醇作为释放介质考察修饰和未修饰纳米粒的体外释药情况,MTT法比较不同剂型和不同浓度紫杉醇对SKOV-3增殖的抑制作用。结果: F-CS-PLGA-NPs的粒径为（321±0.76）nm,电位为（22.6±0.26）mV,载药量为（5.1±0.25）%,包封率为（41.96±1.96）%。修饰和未修饰纳米粒的体外释药曲线相似,在最初24 h内约有35%药物释放,随后释药速度减慢,纳米粒以近零级方式释放,144 h累计释药率约为75%。细胞实验结果显示,在紫杉醇浓度相同的情况下,F-CS-PLGA-NPs在不同作用时间对细胞的抑制作用均强于紫杉醇溶液组和普通纳米粒组,F-CS-PLGA-NPs对SKOVS细胞增殖的抑制作用在一定程度上被游离叶酸减弱。结论:叶酸壳寡糖的修饰增加了纳米粒对SKOVS 3细胞的靶向性。     

pH敏感多肽修饰载紫杉醇脂质体的制备及评价

目的制备p H敏感多肽修饰载紫杉醇脂质体(p HS-LP-PTX),并评价其体外性质。方法采用薄膜分散法制备PHS-LP-PTX,MTT实验考察脂质体对MCF-7细胞和Hep G2细胞的毒性,通过细胞摄取实验考察脂质体与肿瘤细胞的结合能力。结果所制备的p HS-LP-PTX在p H6.4时平均粒径为125.5±13.4 nm,Zeta电位为10.47±2.53 m V,24 h内具有良好的血清稳定性。MTT结果显示:p H6.4时,p HS-LP-PTX的细胞毒性优于各对照组。体外细胞摄取实验表明:p H6.4时,MCF-7细胞和Hep G2细胞对p HS-LP-PTX的摄取效率优于p H7.4时和普通脂质体。结论紫杉醇脂质体经过p H敏感多肽修饰后,能增强脂质体在酸性环境下的细胞穿透能力,是一种良好的p H敏感型肿瘤靶向给药系统。     

Active methods of drug loading into liposomes: recent strategies for stable drug entrapment and increased in vivo activity

INTRODUCTION: The use of liposomes increases the therapeutic index of many drugs, and also offers drug targeting and controlled release. The commercial impact of liposomes is strengthened by the invention of several active drug encapsulation methods, allowing the encapsulation of several weak base or weak acid drugs with very high drug-to-lipid ratios. AREAS COVERED: In recent years, there have been reports on several new approaches to retain more hydrophobic drugs inside liposomes, in the circulation. Most of these methods apply drug precipitation inside preformed liposomes, as low soluble complexes with ions or chemicals. In some cases, drug derivatization was applied to enable active encapsulation of hydrophobic drugs, previously not reported to encapsulate, by active or remote loading. This review presents and compares most of the existing methods of active drug encapsulation and outlines recent strategies to achieve stable drug encapsulation in vivo. EXPERT OPINION: At present, there is no single universal encapsulation method that offers stable encapsulation of most drugs; each drug requires a different approach to manage all of its properties. Now is the time to combine all these strategies to achieve the goal of a complex, but successful, anticancer therapy.     

Characterization and in-vivo ocular absorption of liposome-encapsulated acyclovir.

The potential of liposomes as an in-vivo ophthalmic drug delivery system for acyclovir was investigated. The drug-membrane interaction was evaluated by means of differential scanning calorimetry analysis. These experiments showed that acyclovir is able to interact with both positively and negatively charged membranes via electrostatic or hydrogen bonds. No interaction was observed with neutral membranes made up of dipalmitoylphosphatidylcholine. Different liposome preparation procedures were carried out to encapsulate acyclovir. The drug encapsulation mainly depends on the amount of water which the liposome system is able to entrap. In the case of multilamellar vesicles, charged systems showed the highest encapsulation efficiency. No particular difference in the encapsulation efficiency was observed for oligolamellar vesicles prepared with the reverse-phase evaporation technique. Oligolamellar liposomes showed the highest acyclovir encapsulation parameters and had release profiles similar to those of multilamellar liposomes. In-vivo experiments using male New Zealand albino rabbits were carried out to evaluate the aqueous humour concentration of acyclovir bioavailability. The most suitable ophthalmic drug delivery system was oligolamellar systems made up of dipalmitoylphosphatidylcholine-cholesterol-dimethyldioctadecyl glycerole bromide (7:4:1 molar ratio), which presented the highest encapsulation capacity and were able to deliver greater amounts of the drug into the aqueous humour than a saline acyclovir solution or a physical liposome/drug blend.     

Lyophilized Paclitaxel Magnetoliposomes as a Potential Drug Delivery System for Breast Carcinoma via Parenteral Administration: <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">in Vivo</Emphasis> Studies

No HeadingPurpose. The study reports in vitro and biological evaluation of lyophilized negatively charged paclitaxel magnetic liposomes as a potential carrier for breast carcinoma via parenteral administration.Methods. Paclitaxel in magnetoliposomes were extracted by centrifugation and quantified by high-performance liquid chromatography (HPLC). Biological properties were studied using pharmacokinetics, in vivo distribution and cytotoxicity assays, as well as a mouse model of EMT-6 breast cancer.Methods. Pharmacokinetic studies showed that encapsulation of paclitaxel in magnetoliposomes produced marked difference over the drug in Cremophor EL/ethanol pharmacokinetics, with an increased t_1/2 19.37 h against 4.11 h. For in vivo distribution, paclitaxel concentration of lyophilized magnetoliposomes in the tumor was much higher than that of lyophilized conventional liposomes or Cremophor EL/ethanol, whereas in heart it was much lower than the latter two formulations via s.c. and i.v. administration. Lyophilized paclitaxel magnetic liposomes showed more potency on the therapy of breast cancer than other formulations via s.c. and i.p. administration.Conclusions. The current study demonstrates that paclitaxel magnetoliposomes can effectively be delivered to tumor and exert a significant anticancer activity with fewer side effects in the xenograft model.     

胸腺五肽脂质体的研制

目的:制备胸腺五肽脂质体并进行质量评价。方法:采用复乳法制备胸腺五肽脂质体,以聚乳酸-羟基乙酸共聚物(PLGA)及卵磷脂为成球材料、以胸腺五肽为主药制备脂质体。以明胶浓度、PLGA浓度和卵磷脂浓度为考察因素,以包封率和载药量为考察指标设计L(934)正交试验优化基质处方并进行验证试验。通过测定优化处方所制脂质体粒径、包封率、体外累积释放百分率等评价脂质体质量。结果:优化基质处方为明胶、PLGA和卵磷脂浓度分别为100、200、100mg.mL-1。所制脂质体形态完整,平均粒径为(9.03±0.83)μm,载药量与包封率分别为(1.81±0.03)与(74.4±1.4),20d的累积释药百分率达90以上。结论:所制胸腺五肽脂质体工艺简单、重现性好,包封率和载药量高,具有显著的缓释作用。     

去氢骆驼蓬碱脂质体制备工艺优化及抗肝癌活性

目的 制备去氢骆驼蓬碱脂质体并对其制备工艺进行优化，评价脂质体的相关表征及对肝癌细胞的毒性。方法 用薄膜水化法制备去氢骆驼蓬碱脂质体。以包封率作为评价指标，以大豆卵磷脂和药物的质量比、大豆卵磷脂与胆固醇的质量比和超声时间作为评价因素对脂质体包封率的影响。并对脂质体的粒径、Zeta电位、外观和稳定性进行评价。CCK-8法对比去氢骆驼蓬碱和去氢骆驼蓬碱脂质体的抗肝癌细胞增殖活性。结果 最优制备工艺：大豆卵磷脂和药物的质量比为11.4：1，大豆卵磷脂与胆固醇的质量比为4.4：1，超声时间为33 min。在此条件下制备的脂质体的包封率为81.88%，粒径为143.65 nm，Zeta电位为-12.68 mV，低温环境稳定性良好，具有缓释效应。去氢骆驼蓬碱脂质体的抗肝癌细胞增殖活性大于裸药。结论 所制得的去氢骆驼蓬碱脂质体包封率和稳定性均符合标准。将去氢骆驼蓬碱制备成为脂质体能提高其抗肝癌细胞增殖活性。     

西罗莫司脂质体的制备及处方因素考察

目的 制备西罗莫司脂质体并对处方进行筛选,以期得到高包封率的脂质体制剂.方法 选用乙醇注入法制备西罗莫司脂质体,微柱离心-HPLC法测定包封率,以包封率为评价指标,考察磷脂浓度、磷脂胆固醇质量比、药脂比、水相介质pH等因素对脂质体的影响,在此基础上运用正交设计对处方进行优化.结果 正交试验结果表明磷脂浓度为4%,磷脂与胆固醇质量比例为8:1,药物磷脂质量比为1:20,水相pH为7.4为最佳处方,制得的脂质体包封率为(82.11±2.13)%.结论 优选出最佳处方,制得的西罗莫司脂质体包封率高,重现性好.     

Encapsulation enhancement and stabilization of insulin in cationic liposomes

The purpose of this study was to enhance encapsulation efficiency and sustained-release delivery for parenteral administration of a protein drug. To reduce the administration frequency of protein drugs, it is necessary to develop sustained delivery systems. In this study, protein drug-loaded cationic liposomes were formulated with dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), dioleoyl-3-trimethylammonium-propane (DOTAP), and cholesterol (CH) at a molar ratio of DOPE/DOTAP/CH of 2/1.5/2. Five mol% of distearoylphosphatidyl ethanolamine polyethylene glycol (DSPE-PEG) was added prior to encapsulation of the drug into liposomes. Insulin was chosen as a model protein drug and encapsulation efficiency was evaluated in various liposomes with and without DSPE-PEG. Scanning electron microscopy was used to examine the insulin-loaded cationic liposomes. Structural analysis was performed using spectropolarimetry. Additionally, the stability and cytotoxicity of insulin-loaded cationic liposomes were evaluated. Liposomes coated with DSPE-PEG showed higher insulin encapsulation efficiency than did those without DSPE-PEG, but not significantly. Moreover, among the liposomes coated with DSPE-PEG, those hydrated with 10% sucrose showed higher encapsulation efficiency than did liposomes hydrated in either phosphate-buffered saline or 5% dextrose. In vitro release of insulin was prolonged by cationic liposomes. Our findings suggest that cationic liposomes may be a potential sustained-release delivery system for parenteral administration of protein and peptide drugs to prolong efficacy and improve bioavailability.     

Preparation and the in-vivo evaluation of paclitaxel liposomes for lung targeting delivery in dogs

Objectives The aim of this study was to develop paclitaxel liposomes for a lung targeting delivery system. Methods The liposomes composed of Tween‐80/HSPC/cholesterol (0.03 : 3.84 : 3.84, mol/mol), containing paclitaxel and lipids (1 : 40, mol/mol), were prepared by a combination of solid dispersion and effervescent techniques, and then subjected to ultrasonication. The pharmacokinetics and biodistribution of liposomal and injectable formulation of paclitaxel in dogs were studied after intravenous administration. Key findings The mean diameter, polydispersity index, zeta‐potential and entrapment efficiency of the liposomes were 501.60 ± 15.43 nm, 0.28 ± 0.02, ?20.93 ± 0.06 mV and 95.17 ± 0.32%, respectively. The liposomal formulation kept stable for at least 3 months at 6 ± 2°C and didn't cause haemolysis. The liposome carrier decreased the area under the curve and terminal half‐life of paclitaxel compared with paclitaxel injection ranging from 0.352 ± 0.031 mg/l*h and 0.0671 ± 0.144 h to 0.748 ± 0.062 mg/l*h and 1.978 ± 0.518 h, respectively. The paclitaxel liposomes produced a drug concentration in the lung that was markedly higher than that in other organs or tissues and was about 15‐fold of that of paclitaxel injection at 2 h. Conclusions To sum up, these results demonstrated that the paclitaxel liposomes are an effective lung targeted carrier in the treatment of lung cancer.     

Development of a new topical system: Drug-in-cyclodextrin-in-deformable liposome

A new delivery system for cutaneous administration combining the advantages of cyclodextrin inclusion complexes and those of deformable liposomes was developed, leading to a new concept: drug-in-cyclodextrin-in-deformable liposomes. Deformable liposomes made of soybean phosphatidylcholine (PC) or dimyristoylphosphatidylcholine (DMPC) and sodium deoxycholate as edge activator were compared to classical non-deformable liposomes. Liposomes were prepared by the film evaporation method. Betamethasone, chosen as the model drug, was encapsulated in the aqueous cavity of liposomes by the use of cyclodextrins. Cyclodextrins allow an increase in the aqueous solubility of betamethasone and thus, the encapsulation efficiency in liposome vesicles. Liposome size, deformability and encapsulation efficiency were calculated. The best results were obtained with deformable liposomes made of PC in comparison with DMPC. The stability of PC vesicles was evaluated by measuring the leakage of encapsulated calcein on the one hand and the leakage of encapsulated betamethasone on the other hand. In vitro diffusion studies were carried out on Franz type diffusion cells through polycarbonate membranes. In comparison with non-deformable liposomes, these new vesicles showed improved encapsulation efficiency, good stability and higher in vitro diffusion percentages of encapsulated drug. They are therefore promising for future use in ex vivo and in vivo experiments.