聚乳酸/聚乙二醇琥珀酸酯-姜黄素纳米粒的制备及体外评价*

背景：聚乳酸及其共聚物是一类具有良好生物相容性的可降解高分子材料,已被广泛用于可生物降解型药物缓释或靶向给药系统中。 目的：探索载药纳米粒制备条件对包封率和载药量的影响,确定最佳制备工艺条件。 方法：以维生素E1000聚乙二醇琥珀酸酯(TPGS)为乳化剂、姜黄素为模型药物、聚乳酸为载体材料,采用O/W型乳化-溶剂挥发法制备聚乳酸-姜黄素纳米粒,以包封率和载药量为主要指标,单因素实验探索影响两指标的主要因素,再正交试验设计优化制备工艺。 结果与结论：通过正交试验设计制备聚乳酸-姜黄素纳米粒的最佳工艺为：水油相比10∶1,聚合物浓度15 g/L,药物浓度3 g/L,乳化剂TPGS浓度0.03%。以此工艺制备的载药纳米粒外形圆整光滑,粒度分布较为均匀,平均粒径为167.5 nm,包封率为89.52%,载药量为13.72%,纳米粒前期突释不明显具有良好的缓释作用。该工艺稳定、简单可行,优化制备工艺得到的聚乳酸-姜黄素纳米粒粒径适中、包封率和载药量较高。     

一种新型可降解缓释微系统的优化设计

多腔体的微型可降解高分子聚合物药物缓释系统是一种新型给药技术,其载体结构是利用MEMS工艺的制备特点,结合药物释放的要求和高分子聚合物生物降解特性进行设计的.为了达到该系统在体内长期释药的性能,对释药载体的结构进行参数优化十分必要.文中建立了具有多腔体的微型可降解高分子聚合物给药载体的释药模型以及载体的结构优化模型,仿真及优化结果表明该模型可以用来指导基于可降解材料的结构优化设计.     

甘草酸表面修饰万乃洛韦白蛋白纳米粒的制备及其肝靶向性研究

以万乃洛韦为模型药物 ,去溶剂化法制备普通载药纳米粒 ,结合高碘酸盐氧化法制备甘草酸 -万乃洛韦白蛋白纳米粒偶联物。对其表面甘草酸密度、形态、大小及其分布、体外释药特性、载药量、包封率、动物体内肝分布和体外肝细胞的摄取情况进行了研究。修饰纳米粒表面甘草酸密度为 9;平均粒径 d0 .5=2 6 8± 2 3nm;载药量1.35 % ;包封率 6 8.76 % ;体外释药符合双相动力学规律 ;对肝细胞具有选择靶向性。静注 15 min后 ,有 6 9.89%集中在肝脏 ,对照组为 6 4 .82 % ,二者之间存在显著差异 (P<0 .10 )。甘草酸表面修饰白蛋白纳米粒制备成功 ,为肝细胞靶向给药提供了新途径。     

阿糖胞苷纳米粒的制备及其释药规律研究

采用乳化聚合法制备阿糖胞苷纳米粒，研究其体内外释药特性。结果表明阿糖胞苷纳米粒体外释药规律符合双指数方程，有明显的缓释作用。在家兔体内的药物动力学过程符合二室模型，与阿糖胞苷注射剂相比，t1／2β和MRT延长，CL降低，表明阿糖胞苷纳米粒可显著延长阿糖胞苷在体内存留时间，具有明显的缓释特征。     

纳米粒载体研究进展

纳米粒是近年来载体研究中的热点。理想的纳米粒载体应有特异靶向性、药物释放可控性，无毒性以及可生物降解等。综述了纳米粒的研究进展，并对其应用前景进行展望。     

硫酸庆大霉素-壳聚糖纳米粒的制备及性能评价

背景：庆大霉素珠链是较早用于治疗慢性骨髓炎的局部释药系统,但是由于其不能在体内降解吸收,须二次取出,因而限制了其的应用。因此国内外学者一直致力于可吸收材料负载抗生素装置的研究。 目的：制备负载庆大霉素的壳聚糖纳米粒,评价其性能,观察其体外释药行为及体外抗金黄色葡萄球菌的作用。 方法：以壳聚糖为药用载体,硫酸庆大霉素为模型药物,三聚磷酸钠为离子交联剂,采用离子交联法制备庆大霉素-壳聚糖纳米粒,在MH平板上进行抑菌实验,观察及评价其抑制金黄色葡萄球菌的作用。 结果与结论：制备的纳米粒形态为类圆形,粒径为40~70 nm,包封率及载药量分别为31.3%和15.4%,体外释药可持续14 d左右,对金黄色葡萄球菌的体外抑菌效果可持续25 d,在第5天纳米粒的抑菌作用达到最大,随着时间的推移,抑菌圈逐渐缩小。     

乳酸-羟基乙酸共聚物载药纳米粒的制备及体外释药性

背景：医用纳米粒作为药物传递的新型载体,目前已经成为医药领域研究的重点。 目的：构建以生物可降解材料乳酸-羟基乙酸共聚物为载体,负载抗肿瘤药物5-氟尿嘧啶的载药纳米粒。 方法：利用复乳-溶剂挥发法制备乳酸-羟基乙酸共聚物载药纳米粒。场发射扫描电子显微镜观察纳米粒表面形态;激光粒度分析仪测定粒径分布并计算成球率;紫外分光光度计测定5-氟尿嘧啶载药量、包封率,并对体外释药进行评估。 结果与结论：纳米粒呈球性,平均粒径为(186±14) nm,成球率、载药量和包封率分别为70.8%、6.6%、28.1%,体外释药有突释现象,24 h内5-氟尿嘧啶累积释药量达36.2%,10 d达83.6%。提示成功制备乳酸-羟基乙酸共聚物载药纳米粒,其具有缓释效应。     

纳米粒载体研究进展

纳米粒是近年来载体研究中的热点。理想的纳米粒载体应有特异靶向性、药物释放可控性,无毒性以及可生物降解等。综述了纳米粒的研究进展,并对其应用前景进行展望。     

载阿霉素聚合物纳米粒的制备、表征与体内外性能研究

目的 以两亲性三嵌段共聚物聚己内酯-聚乙二醇-聚己内酯(PCL-b-PEG-b-PCL)为载体材料,制备包载抗肿瘤药物阿霉素(DOX)的聚合物纳米粒,并对其进行体内外性能研究.方法 以PCL-b-PEG-b-PCL作为载体材料,通过薄膜水化超声分散法制备出载DOX的聚合物纳米粒,并对其形态、粒径及其分布、载药量及包封率等理化性能进行表征.采用MTS法研究载DOX聚合物纳米粒对EMT6乳腺癌细胞的细胞毒性,激光扫描共聚焦显微镜(CLSM)观察EMT6细胞对纳米粒的细胞吞噬,离体脏器荧光成像研究纳米粒在荷EMT6乳腺癌小鼠的组织分布.结果 通过薄膜水化超声分散法成功制备出载DOX聚合物纳米粒,透射电镜和扫描电镜结果表明,该纳米粒呈球形,大小均匀,具有明显的核壳结构.粒度分析表明,载DOX聚合物纳米粒的平均粒径为130.8 nm,且粒径分布较窄(多分散系数为0.200).DOX在聚合物纳米粒中的包封率和载药量分别为(86.71±2.05)％和(8.71±0.57)％.细胞毒性研究发现,空白纳米粒对EMT6细胞无毒性,而载入DOX后,DOX-NPs的细胞毒性具有时间和剂量依赖性;在DOX质量浓度较高(20 μg/ml和40μg/ml)和孵育时间较长(72 h)时,载DOX聚合物纳米粒与游离DOX的细胞毒性相当,差异无统计学意义(P＞0.05).CLSM观察发现,EMT6乳腺癌细胞与载DOX聚合物纳米粒共同孵育后,DOX的荧光在细胞质和细胞核中均有分布,但与游离DOX共同孵育后,DOX的红色荧光主要出现在细胞核中.离体脏器荧光成像研究表明,分别对荷EMT6乳腺癌小鼠尾静脉注射载DOX聚合物纳米粒及游离DOX后,载DOX聚合物纳米粒可通过增强渗透和滞留效应(EPR)在肿瘤部位有效聚集.结论 载DOX聚合物纳米粒具有适合静脉注射的粒径、高载药量和包封率及良好的被动靶向特性,是一种在肿瘤治疗中具有潜在应用前景的纳米药物递送系统.     

蛋白多肽类药物口服纳米给药：现状、问题与前景

背景：研发药物新剂型和制剂新技术已成为有望提高蛋白多肽利用率的热点,尤其是近几年的纳米技术的研究进展更是促进了蛋白质药物的临床应用。 目的：综述蛋白口服纳米给药的研究现状。 方法：应用计算机检索CNKI数据库、SCI数据库1996至2014年文献,检索中英文关键词为“蛋白多肽,纳米粒,口服制剂;protein,peptide drugs,nanoparticles,oral administration”。 结果与结论：纳米材料种类、纳米粒粒径、表面电荷及其表面修饰等对药物的包封率、释药速度、纳米粒在胃肠道内的稳定性及透过肠黏膜的能力等方面有很大影响。纳米粒可增加蛋白药物的稳定性,提高药物的生物利用度;纳米粒的靶向性可减少某些药物的不良反应;纳米粒的缓释作用可以减少药物的用量,增加药物的体内循环时间。但纳米技术目前仍有很多问题有待解决：制备过程中不可避免地会使一些蛋白药物丧失活性;药物的包封率及载药量有待提高;蛋白突释问题不能完全解决;纳米粒目前大规模生产还很困难等。  中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

Synthesis and in vitro drug release behavior of amphiphilic triblock copolymer nanoparticles based on poly (ethylene glycol) and polycaprolactone

Novel BAB type amphiphilic triblock copolymers consisting of poly (ethylene glycol) (PEG) (B) as hydrophilic segment and poly (epsilon-caprolactone) (PCL) (A) as hydrophobic block were prepared by coupling reaction using L-lysine methyl ester diisocyanate (LDI) as the chain extender. The triblock copolymers obtained were characterized by FT-IR, 1H NMR, GPC, and DSC. Core-shell type nanoparticles were prepared by nanoprecipitation method and below 100 nm nanoparticles were obtained due to their specific structure. Transmission electron microscopy image demonstrated that these nanoparticles were spherical in shape. Stability of the nanoparticles in biological media was evaluated. Poorly water-soluble anticancer drug 4'-demethyl-epipodophyllotoxin (DMEP) was chosen for controlled drug release because it was easily encapsulated into polymeric nanoparticles via hydrophobic interaction. In vitro release behavior of DMEP from polymeric nanoparticles was investigated, the results showed that the drug release rate can be modulated by the variation of the copolymer composition.     

Amoxicillin-loaded polyethylcyanoacrylate nanoparticles: influence of PEG coating on the particle size, drug release rate and phagocytic uptake

Polyethyleneglycol (PEG)-coated polyethylcyanoacrylate (PECA) nanoparticles loaded with amoxicillin were prepared and the influence of the PEG coating on the particle size, zeta potential, drug release rate and phagocytic uptake by murine macrophages was studied. Experimental results show that this colloidal drug delivery system could be useful for intravenous or oral administration. The profile of amoxicillin release from PECA nanoparticles system was studied under various conditions similar to those of some corporeal fluids. In all these experiments, amoxicillin release in the free form was studied by HPLC analysis. Experimental results showed that at pH 7.4 drug release rises when molecular weight of PEG added to polymerization medium increases; in human plasma on the contrary drug release is reduced as molecular weight of PEG rises. Phagocytosis was evaluated by incubating amoxicillin-loaded PECA nanoparticles with murine macrophages and determining the amount of phagocytized nanoparticles by dosing the amoxicillin present inside the macrophages. The results of this study showed significative differences between nanoparticles prepared in the presence or in the absence of PEG and demonstrated that the PEG coating reduces the macrophages uptake. These results suggest that nanoparticles prepared in the presence of PEG are stealth carriers, which could be an injectable colloidal system able to avoid MPS recognition after intravenous injection. Experimental data of drug release at pH 1.1 and in the presence of urease, taking into account the mucoadhesive properties of polyalkylcyanoacrylate nanoparticles and the activity of the amoxicillin versus Helicobacter pylori, suggest moreover that the colloidal drug delivery system obtained in our laboratory could be useful for the treatment of diseases caused by H. pylori by peroral administration.     

Single-step surface functionalization of polymeric nanoparticles for targeted drug delivery

Targeted drug delivery using nanocarriers is achieved by functionalizing the carrier surface with a tissue-recognition ligand. Current surface modification methods require tedious and inefficient synthesis and purification steps, and are not easily amenable to incorporating multiple functionalities on a single surface. In this report, we describe a versatile, single-step surface functionalizing technique for polymeric nanoparticles. The technique utilizes the fact that when a diblock copolymer like polylactide–polyethylene glycol (PLA–PEG) is introduced in the oil/water emulsion used in polymeric nanoparticle formulation, the PLA block partitions into the polymer containing organic phase and PEG block partitions into the aqueous phase. Removal of the organic solvent results in the formation of nanoparticles with PEG on the surface. When a PLA–PEG–ligand conjugate is used instead of PLA–PEG copolymer, this technique permits a ‘one-pot’ fabrication of ligand-functionalized nanoparticles. In the current study, the IAASF approach facilitated the simultaneous incorporation of biotin and folic acid, known tumor-targeting ligands, on drug-loaded nanoparticles in a single step. Incorporation of the ligands on nanoparticles was confirmed by using NMR, surface plasmon resonance, transmission electron microscopy and tumor cell uptake studies. Simultaneous functionalization with both ligands significantly enhanced nanoparticle accumulation in tumors in vivo, and resulted in greatly improved efficacy of paclitaxel-loaded nanoparticles in a mouse xenograft tumor model. This new surface functionalization approach will enable the development of targeting strategies based on the use of multiple ligands on a single surface to target a tissue of interest.     

Effects of PEG tethering chain length of vitamin E TPGS with a Herceptin-functionalized nanoparticle formulation for targeted delivery of anticancer drugs

Drug formulation by ligand conjugated nanoparticles of biodegradable polymers has become one of the most important strategies in drug targeting. We have developed in our previous work nanoparticles of a mixture of two vitamin E TPGS based copolymers PLA-TPGS and TPGS-TOOH with the latter for Herceptin conjugation for targeted delivery of anticancer drugs such as docetaxel to the cancer cells of human epidermal growth factor receptor 2 (HER2) overexpression. In this research, we investigated the effects of the PEG chain length in TPGS, which is in fact a PEGylated vitamin E, on the cellular uptake and cytotoxicity of the drug formulated in the Herceptin-conjugated nanoparticles of PLA-TPGS/TPGS-COOH blend (NPs). Such NPs of PEG1000, PEG2000, PEG3350 and PEG5000, i.e. the PEG of molecule weight 1000, 2000, 3350 and 5000, were prepared by the nanoprecipitation method and characterized for their size and size distribution, drug loading, surface morphology, surface charge and surface chemistry as well as in vitro drug release profile, cellular uptake and cytotoxicity. We found among such nanoparticles, those of PEG1000, i.e. of the shortest PEG tethering chain length, could result in the best therapeutic effects, which are 24.1%, 37.3%, 38.1% more efficient in cellular uptake and 68.1%, 90%, 92.6% lower in IC₅₀ (thus higher in cytotoxicity) than the Herceptin-conjugated nanoparticles of PLA-TPGS/TPGS-COOH blend of PEG2000, PEG3350 and PEG5000 respectively in treatment of SK-BR-3 cancer cells which are of high HER2 overexpression. We provided a theoretical explanation from surface mechanics and thermodynamics for endocytosis of nanoparticles.     

PLGA–lecithin–PEG core–shell nanoparticles for controlled drug delivery

Current approaches to encapsulate and deliver therapeutic compounds have focused on developing liposomal and biodegradable polymeric nanoparticles (NPs), resulting in clinically approved therapeutics such as Doxil/Caelyx and Genexol-PM, respectively. Our group recently reported the development of biodegradable core–shell NP systems that combined the beneficial properties of liposomal and polymeric NPs for controlled drug delivery. Herein we report the parameters that alter the biological and physicochemical characteristics, stability, drug release properties and cytotoxicity of these core–shell NPs. We further define scalable processes for the formulation of these NPs in a reproducible manner. These core–shell NPs consist of (i) a poly(d,l-lactide-co-glycolide) hydrophobic core, (ii) a soybean lecithin monolayer, and (iii) a poly(ethylene glycol) shell, and were synthesized by a modified nanoprecipitation method combined with self-assembly. Preparation of the NPs showed that various formulation parameters such as the lipid/polymer mass ratio and lipid/lipid–PEG molar ratio controlled NP physical stability and size. We encapsulated a model chemotherapy drug, docetaxel, in the NPs and showed that the amount of lipid coverage affected its drug release kinetics. Next, we demonstrated a potentially scalable process for the formulation, purification, and storage of NPs. Finally, we tested the cytotoxicity using MTT assays on two model human cell lines, HeLa and HepG2, and demonstrated the biocompatibility of these particles in vitro. Our data suggest that the PLGA–lecithin–PEG core–shell NPs may be a useful new controlled release drug delivery system.     

Multi-core vesicle nanoparticles based on vesicle fusion for delivery of chemotherapic drugs

The Pluronic nanoparticles (NPs) composed of Pluronic (F-68) and liquid polyethylene glycol (PEG, molecular wt: 400) containing docetaxel (DTX) were stabilized with the vesicle fusion. When DTX-loaded Pluronic NPs were mixed with vesicles in the aqueous medium, DTX-loaded Pluronic NPs were incorporated into vesicles to form multi-core vesicle NPs. The morphology and size distribution of multi-core vesicle NPs were observed using FE-SEM, cryo-TEM and a particle size analyzer. To apply multi-core vesicle NPs as a delivery system for DTX, a model anti-cancer drug, the release pattern of DTX was observed and the tumor growth was monitored by injecting the DTX-loaded multi-core vesicle NPs into the tail veins of tumor-bearing mice. We also evaluated the time-dependent excretion profile, in?vivo biodistribution, circulation time, and tumor targeting capability of multi-core vesicle NPs using a non-invasive live animal imaging technology.     

Regulating the surface poly(ethylene glycol) density of polymeric nanoparticles and evaluating its role in drug delivery in vivo

Poly(ethylene glycol) (PEG) is usually used to protect nanoparticles from rapid clearance in blood. The effects are highly dependent on the surface PEG density of nanoparticles. However, there lacks a detailed and informative study in PEG density and in vivo drug delivery due to the critical techniques to precisely control the surface PEG density when maintaining other nano-properties. Here, we regulated the polymeric nanoparticles' size and surface PEG density by incorporating poly(ε-caprolactone) (PCL) homopolymer into poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG–PCL) and adjusting the mass ratio of PCL to PEG–PCL during the nanoparticles preparation. We further developed a library of polymeric nanoparticles with different but controllable sizes and surface PEG densities by changing the molecular weight of the PCL block in PEG–PCL and tuning the molar ratio of repeating units of PCL (CL) to that of PEG (EG). We thus obtained a group of nanoparticles with variable surface PEG densities but with other nano-properties identical, and investigated the effects of surface PEG densities on the biological behaviors of nanoparticles in mice. We found that, high surface PEG density made the nanoparticles resistant to absorption of serum protein and uptake by macrophages, leading to a greater accumulation of nanoparticles in tumor tissue, which recuperated the defects of decreased internalization by tumor cells, resulting in superior antitumor efficacy when carrying docetaxel.     

Hercon technology for transdermal delivery of drugs

The Hercon controlled drug delivery technology is based on a multi-layered laminated polymeric structure, in which a layer of vinyl chloride copolymer or terpolymer containing the drug is sandwiched between two or more layers of polymeric films. The drug is released from the device at a controlled rate by a process of diffusion through the reservoir and one of the outer layers, which can function as a rate controlling membrane. This basic technology has been successfully utilized for the development and commercialization of Nitroglycerin Transdermal System (NTS, Bolar Pharmaceutical Co., Inc). In vitro and in vivo investigations of transdermal delivery of different other drugs from the Hercon polymeric devices have indicated the feasibility of using this system to meet a variety of therapeutic needs.     

Tissue anti-adhesion potential of ibuprofen-loaded PLLA-PEG diblock copolymer films

This study was designed to evaluate the effect of polyethylene glycol (PEG) and nonsteroidal anti-inflammatory drug (ibuprofen) on the prevention of postsurgical tissue adhesion. For this, poly(L-lactic acid) (PLLA)-PEG diblock copolymers were synthesized by ring opening polymerization of L-lactide and methoxy polyethylene glycol (Mw 5000) of different compositions. The synthesized copolymers were characterized by gel permeation chromatography and 1H-nuclear magnetic resonance spectroscopy. PLLA-PEG copolymer films were prepared by solvent casting. The prepared copolymer films were more flexible and hydrophilic than the control PLLA film, as investigated by the measurements of glass transition temperature, water absorption content, and water contact angle. The drug release behavior from the ibuprofen (10 wt%)-loaded copolymer films was examined by high performance liquid chromatography. It was observed that the drug was released gradually up to about 40% of total loading amount after 20 days, depending on PEG composition; more drug release from the films with higher PEG compositions. In vitro cell adhesions on the copolymer films with/without drug were compared by the culture of NIH/3T3 mouse embryo fibroblasts on the surfaces. For in vivo evaluation of tissue anti-adhesion potential, the copolymer films with/without drug were implanted between the cecum and peritoneal wall defects of rats and their tissue adhesion extents were compared. It was observed that the ibuprofen-containing PLLA-PEG films with high PEG composition (particularly PLLA113-PEG113 film with PEG composition, 50 mol%) were very effective in preventing cell or tissue adhesion on the film surfaces, probably owing to the synergistic effects of highly mobile, hydrophilic PEG and anti-inflammatory drug, ibuprofen.     

聚己内酯-吐温80共聚物纳米粒在神经胶质瘤化疗中的应用

目的 研究新型载多西紫杉醇聚己内酯-吐温80共聚物(PCL-Tween 80)纳米粒在神经胶质瘤化疗中的应用.方法 以PCL-Tween 80和聚己内酯为材料,利用改良的溶剂萃取/挥发方法制备载多西紫杉醇纳米粒并进行性质表征.利用激光共聚焦显微镜观察纳米粒的细胞摄取情况,并利用噻唑蓝(MTT)法测定纳米粒对C6细胞的细胞毒作用.结果 载药纳米粒呈球形,粒径约为200 nm.PCL-Tween 80纳米粒的载药量为10%,28 d内可以释放包裹药物的34.90%.与同浓度的泰素帝(Taxotere(R))比较,载多西紫杉醇PCL-Tween 80纳米粒对C6细胞的细胞毒性作用更强.结论 载多西紫杉醇PCL-Tween 80纳米粒用于神经胶质瘤的化疗极具应用前景.