双重响应二硫化钼纳米载药体系的制备及其性能研究

摘要 目的：制备肿瘤微环境响应释放的靶向二硫化钼纳米载药体系,并评价其载药量和释药性能。方法：以水热法合成的MoS₂纳米片为基底,利用MoS₂纳米片上的S空缺位点连接硫辛酸聚乙二醇羧酸,然后通过酰胺反应连接精氨酸-甘氨酸-天冬氨酸（RGD）靶向分子,再连接上交联剂3-(2-吡啶二硫代)丙酸N-琥珀酰亚胺酯（SPDP）,得到药物载体MoS2-PEG-RGD-SPDP（MPRS）,MPRS进一步与巯基化的阿霉素（DOX）反应,形成MPRS-DOX纳米载药体系。通过透射电子显微镜（TEM）,X-射线光电子能谱仪（XPS）以及纳米粒度电位仪对合成的材料进行表征;利用紫外可见分光光度计测试MPRS的载药性能,采用荧光分光光度计考察MPRS-DOX的释药性能。结果：成功合成MPRS-DOX纳米载药体系,其粒径大小在200 nm左右,Zeta电位为+28.2 mV;其载药效率为86.8%,载药量为53.5%。体外释药实验表明,在10 mM 谷胱甘肽（GSH）和pH=5.5的条件下DOX释放量最多。结论：成功制备了粒径合适的MPRS-DOX纳米载药体系,MPRS-DOX具有GSH和pH双重响应性,可实现预期的模拟肿瘤微环境内控制释放药物。这种GSH和pH双重响应的纳米载药体系为新一代刺激响应型纳米载药系统的构建提供了新的思路。     

疏水蛋白载药系统研究进展

药物的临床使用常常因为其强疏水性、低稳定性和高毒副作用等问题受到限制。日新月异的药物递送体系(DDS)可以有效地包载与保护药物,提高其生物相容性、作用特异性和治疗效果。疏水蛋白是真菌在如子实体发育等特殊时期分泌的小分子蛋白质。其独特的两亲性不仅有助于它们自组装成胶束和载送疏水性药物,还便于它们修饰和改造其它载药体系。其超低的免疫原性和细胞毒性则进一步支撑了它们在药物递送中的应用。对近几年基于疏水蛋白所发展的载药系统的研究进展进行了综述。     

基于酸敏感的双响应抗癌药物载体的研究进展

为了达到更好的肿瘤治疗效果,研究者们针对肿瘤微环境设计出了双重和多重响应性智能纳米药物载体。其中基于酸敏感的双重响应性智能纳米药物载体的研究是最广泛、最常见的一种。在当前的研究中,该智能纳米药物载体已经初步实现了体内长循环、有效地抵达肿瘤细胞、在特定肿瘤微环境下控制药物释放等功效,增加了药物抗肿瘤疗效,有效地减少了药物对机体中正常组织的伤害。但是这类研究仍存在许多问题需要解决,如价格昂贵、载体结构复杂、体内药物传递机理不明确等,使其很难用于临床治疗。这里主要从酸-温度、酸-磁、酸-氧化还原、酸-酶、酸-光和酸-超声几个方面简单介绍了近几年的纳米载体研究进展,为进一步实现纳米药物临床应用奠定基础。     

巨噬细胞装载纳米颗粒用于药物递送

目的:活细胞药物递送系统具有主动靶向至肿瘤部位,防止被免疫系统清除等诸多优势。本文提供了一种巨噬细胞负载纳米颗粒的递送方法,并探讨不同载药量对巨噬细胞的活性以及运动性的影响。方法:通过超声乳化法制备包载阿霉素的DOX@PLGA纳米颗粒。纳米粒度分析仪测量粒径和表面电位,透射电镜观察纳米颗粒形态。将DOX@PLGA纳米颗粒与巨噬细胞共同孵育,即得到负载DOX@PLGA纳米颗粒的巨噬细胞用以药物递送。然后通过CCK-8法、LDH法以及细胞迁移实验检测不同载药量情况下细胞活力水平、细胞损伤程度以及细胞运动性。结果:制备的DOX@PLGA纳米颗粒呈圆形或椭圆形,粒径为109.2±2.3 nm;表面电位为-45.0±2.0 m V;载药量为4.61%。当单个巨噬细胞负载0.15 pg DOX时细胞存活率为:71.5±4.4(%);细胞损伤率为:26.3±1.8(%);迁移率为:61.6±5.7(%)。结论:成功制备巨噬细胞负载DOX@PLGA纳米颗粒的递药系统,载药量适当的情况下载体细胞依然具有良好的活性和运动性。     

刺激响应型纳米载体在肿瘤诊疗中的研究进展

刺激响应型纳米载体是通过对外界刺激响应而产生相应结构或理化性质变化的纳米智能载药体系,具有避免药物过早泄露,提高病灶药物浓度的特点,目前已成为肿瘤诊断和治疗领域的研究热点,广泛用于控制药物的呈递和释放.本文从温度、磁场、超声、光、pH等外源和内源刺激角度,阐述了智能响应型纳米载体近年来在肿瘤诊疗领域的研究进展.     

新型γ-聚谷氨酸自组装纳米胶束的制备及用于蛋白载体的研究

对水溶性的γ-聚谷氨酸(γ-PGA)进行了接枝改性,合成了两亲性γ-聚谷氨酸(γ-PGA)接枝衍生物,采用超声探头法制备胆甾醇基γ-PGA自组装胶束,并以卵清蛋白(OVA)作为模型蛋白,研究其载药和释药性能.结果表明,制备的两亲性胆甾醇基γ-PGA自组装胶束平均粒径为299.6+ 27.3nm,粒径的多分散系数较窄(0.17),且具有较低的细胞毒性;其疏水核-亲水壳的纳米微结构对蛋白药物显示了良好载药性能,对OVA载药量可达118.8 μg/mg,包封率33.5％;体外释药结果显示,负载OVA的甾醇基γ-PGA自组装胶束能延缓蛋白的释放,释药速率与介质pH密切相关.     

还原可降解聚磺酸甜菜碱型纳米水凝胶的制备及载药研究

目的:制备与表征还原可降解的聚磺酸甜菜碱型纳米水凝胶,利用该纳米递药系统包载阿霉素(DOX)并初步评价其抗肿瘤性能。方法:利用回流沉淀聚合的方法合成含二硫键的聚磺酸甜菜碱甲基丙烯酸酯(PSBMA)纳米水凝胶及不含二硫键的PSBMA纳米凝胶(nd-PSBMA);通过粒度仪和透射电镜考察两种纳米水凝胶的粒径、形态以及稳定性;通过考察谷胱甘肽(GSH)对纳米凝胶溶液相对浊度的影响以评价还原环境对两种纳米凝胶的还原可降解性;利用纳米凝胶包载阿霉素(DOX),考察载药凝胶在GSH中的释药行为,并初步评价其对A549肿瘤细胞的杀伤作用。结果:以N, N'-双丙烯酰胱胺为交联剂制备了含二硫键的PSBMA纳米凝胶,其粒径在180～200 nm;同时以N, N'-双丙烯酰胺为交联剂制备了不含二硫键的n-PSBMA纳米凝胶。两种纳米凝胶与小鼠血清共孵育7天水合粒径仍无明显变化,表明磺酸甜菜碱型纳米凝胶具有良好的抗蛋白吸附能力。此外,PSBMA纳米凝胶在GSH溶液中迅速地降解,且降解速度与GSH浓度呈正相关;而nd-PSBMA纳米凝胶在GSH溶液中几乎不降解。载DOX的PSBMA纳米凝胶可在GSH作用下快速的释放药物而载DOX的nd-PSBMA纳米凝胶在GSH作用下缓慢的释放药物;体外细胞实验显示空白纳米凝胶和载药nd-PSBMA对A549细胞无明显毒性作用,但载DOX的PSBMA纳米凝胶可高效地杀死A549肿瘤细胞,其药效与游离DOX相仿。结论:还原可降解的PSBMA纳米水凝胶有望成为智能型控释药物载体。     

D-甘露糖修饰聚合物胶束的制备及其在靶向药物输送中的应用

聚合物胶束作为药物载体具有良好的稳定性和生物相容性,提高疏水性药物溶解性等优势,是一类很有应用潜力的药物传输系统。本研究以合成的共价键连D-甘露糖的双亲性聚合物分子(PGMA-Mannose)为药物载体,包载抗癌药物阿霉素(DOX)制备具有甘露糖受体靶向性和pH敏感药物释放特性的新型载药聚合物胶束。利用激光共聚焦显微镜和MTT细胞毒性评价方法对载药胶束的细胞内吞摄取和毒性进行评价。实验结果表明,载药胶束能特异性识别人乳腺癌细胞MDA-MB-231表面过度表达的甘露糖受体,被癌细胞大量摄取并在细胞溶酶体酸性环境内释放药物,而载药胶束在表面甘露糖受体低表达的HEK293细胞中只有少量摄取。与原药DOX相比,该载药胶束对癌细胞的毒性显著提高,而对正常细胞的毒性较低。因此,该PGMA-Mannose聚合物胶束有望成为一种新型的靶向药物输送系统应用于癌症的治疗。     

交联星型聚合物胶束的制备及其抗肿瘤应用

传统聚合物胶束因稳定性不足容易在血液循环的剪切力及蛋白质的作用下解体，导致封装的化疗药物提前释放，使得药物在体内进行非特异性分布并产生了毒副作用。为解决该问题，文章合成了基于聚赖氨酸的两亲性三嵌段共聚物m PEG-P(LL/LL-LA)-PCL，通过溶剂蒸发法制备非交联胶束DUCM，再利用二硫苏糖醇DTT诱导赖氨酸LA发生交联，在亲疏水壳层之间形成了还原响应型交联网络结构从而制备得到交联胶束DCM。基于内部的交联结构，DCM可以在血液循环中保持稳定，进入肿瘤细胞后，还原响应型交联网络结构中的二硫键会在肿瘤细胞中高表达的谷胱甘肽（GSH）的作用下断裂从而释放化疗药物，达到杀死肿瘤细胞的目的。文章通过合理的结构设计，提高了PEG-PCL胶束的稳定性及刺激响应性，为其他胶束药物传递系统的研发提供了参考。     

超声和pH响应的药物共转运纳米胶束的制备及其生物学性能初探

目的:制备一种超声和p H双重响应的同时载有阿霉素(DOX)与石胆酸(LA)的纳米胶束,实现两种药物的共转运。方法:将叠氮化的石胆酸(LA-(N3)_2)与两个丙炔胺化β-环糊精(β-CD-C≡CH)通过点击反应结合,得到一种两亲性β-环糊精二聚体(LA-(CD)_2)。该环糊精二聚体在水溶液中发生自组装,同时包裹疏水性药物阿霉素,最终得到阿霉素与石胆酸共转运的纳米胶束(LA-CD2/DOX)。通过核磁共振光谱和飞行时间质谱表征LA-(CD)2的结构,透射电镜(TEM)和动态光散射(DLS)表征共转运纳米粒的形貌和大小,动态透析法模拟体外释药,监测在不同p H值和超声作用下纳米胶束的释药特性,同时采用人口腔表皮样癌细胞(KB细胞)测定LA-(CD)2/DOX的细胞毒性。结果:1经核磁共振和飞行时间质谱表征LA-(CD)2成功合成。2透射电镜和动态光散射证实LA-(CD)2自组装成形态规整的纳米胶束,Dz=128 nm,PDI=0.21。3体外释药实验结果表明DOX的释药具有p H和超声双重响应性,而LA的释药只具有p H响应性。4细胞实验证实LA-CD2/DOX的细胞毒性高于DOX和LA。结论:LA-(CD)2/DOX可有望成为一种p H和超声双重响应的抗肿瘤药物共转运纳米载体。     

Preparation and evaluation of warfarin-β-cyclodextrin loaded chitosan nanoparticles for transdermal delivery

The main objective of the present work was to prepare warfarin-β-cyclodextrin (WAF-β-CD) loaded chitosan (CS) nanoparticles for transdermal delivery. CS is a hydrophilic carrier therefore, to overcome the hydrophobic nature of WAF and allow its incorporation into CS nanoparticles, WAF was first complexed with β-cyclodextrin (β-CD). CS nanoparticles were prepared by ionotropic pre-gelation using tripolyphosphate (TPP). Morphology, size and structure characterization of nanoparticles were carried out using SEM, TEM and FTIR, respectively. Nanoparticles prepared with 3:1 CS:TPP weight ratio and 2mg/ml final CS concentration were found optimum. They possessed spherical particles (35±12nm diameter) with narrow size distribution (PDI=0.364) and 94% entrapment efficiency. The in vitro release as well as the ex vivo permeation profiles of WAF-β-CD from the selected nanoparticle formulation were studied at different time intervals up to 8h. In vitro release of WAF-β-CD from CS nanoparticles followed a Higuchi release profile whereas its ex vivo permeation (at pH 7.4) followed a zero order permeation profile. Results suggested that the developed WAF-β-CD loaded CS carrier could offer a controlled and constant delivery of WAF transdermally.     

Intermolecular interaction and morphology investigation of drug loaded ABA-triblock copolymers with different hydrophilic/lipophilic ratios

Copolymers with different hydrophilic/lipophilic ratios (HLR) were used to optimize the compatibility between polymer as drug carrier and quercetin as lipophilic drug. Synthesis of amphiphilic triblock copolymers (TC) of poly(butylene adipate)–poly(ethylene glycol)–poly(butylene adipate) (PBA–PEG–PBA) with different PBA molecular weights is the first approach for this purpose. Polymerization and structural features of the polymers were analyzed by different characterization techniques (GPC, ¹H NMR and FT-IR). Formation of hydrophobic and hydrophilic domains with different ratios in the ABA-triblock copolymers was studied by ¹H NMR. The sunflower-like nanoparticles were prepared by self-assembling of the amphiphilic copolymers in the aqueous solution. The hydrophobic PBA segments formed the central solid-like core which stabilized by the hydrophilic PEG rings. The optimum HLR for these copolymers was determined on the basis of drug release time and profile, obtained from freeze-dried nanoparticle powders. The results indicated that optimum HLR for the sustained quercetin release obtained at higher molecular weight of polyesteric domains. Zeta potential measurements showed that the nanoparticle size was close related to the initial concentrations of the nanoparticle dispersions and the compositions of the triblock copolymers. Moreover, TEM pictures showed that the nanocarriers morphologies were changed by changing HLR of triblock copolymers. The PBA–PEG–PBA nanoparticles also showed good drug loading properties, suggesting that they were very suitable as delivery devices for hydrophobic drugs.     

Release characteristics of three model drugs from chitosan/cellulose acetate multimicrospheres

Chitosan/cellulose acetate multimicrospheres (CCAM) loaded different model drugs were prepared by the method of w/o/w emulsion. Model drugs with different hydrophilicity were selected to investigate the delivery system, such as hydrophilic ranitidine hydrochloride (RT), amphoteric acetaminophen (ACP) and hydrophobic 6-mercaptopurine (6-MP). The size of CCAM loaded RT or ACP were almost the same of 200–280 μm and the size of CCAM loaded 6-MP was only 50–80 μm. With the increasing of hydrophobicity of drug, the holes in the appearance of microspheres became smaller and the loading efficiency increased. The loading efficiency of 6-MP was more than 30% whereas that of RT and ACP was only 10%. The CCAM system had good effect on the controlled release in vitro of all model drugs of different hydrophobicity. However, the release rate was affected by the hydrophobicity of model drug. It became slower with the increasing of hydrophobicity of drugs. The highest release rate was almost 60% during 48 h which was for the hydrophilic drug of RT and the release rate of hydrophobic drug (6-MP) was not more than 30% in the same time.     

Controlled release formulation of tramadol hydrochloride using hydrophilic and hydrophobic matrix system

The effect of concentration of hydrophilic (hydroxypropyl methylcellulose [HPMC]) and hydrophobic polymers (hydrogenated castor oil [HCO], ethylcellulose) on the release rate of tramadol was studied. Hydrophilic matrix tablets were prepared by wet granulation technique, while hydrophobic (wax) matrix tablets were prepared by melt granulation technique and in vitro dissolution studies were performed using United States Pharmacopeia (USP) apparatus type II. Hydrophobic matrix tablets resulted in sustained in vitro drug release (>20 hours) as compared with hydrophilic matrix tablets (<14 hours). The presence of ethylcellulose in either of the matrix systems prolonged the release rate of the drug. Tablets prepared by combination of hydrophilic and hydrophobic polymers failed to prolong the drug release beyond 12 hours. The effect of ethylcellulose coating (Surelease) and the presence of lactose and HPMC in the coating composition on the drug release was also investigated. Hydrophobic matrix tablets prepared using HCO were found to be best suited for modulating the delivery of the highly water-soluble drug, tramadol hydrochloride.     

Folate-functionalized unimolecular micelles based on a degradable amphiphilic dendrimer-like star polymer for cancer cell-targeted drug delivery

A folate-functionalized degradable amphiphilic dendrimer-like star polymer (FA-DLSP) with a well-defined poly(L-lactide) (PLLA) star polymer core and six hydrophilic polyester dendrons based on 2,2-bis(hydroxymethyl) propionic acid was successfully synthesized to be used as a nanoscale carrier for cancer cell-targeted drug delivery. This FA-DLSP hybrid formed unimolecular micelles in the aqueous solution with a mean particle size of ca. 15 nm as determined by dynamic light scattering and transmission electron microscopy. To study the feasibility of FA-DLSP micelles as a potential nanocarrier for targeted drug delivery, we encapsulated a hydrophobic anticancer drug, doxorubicin (DOX), in the hydrophobic core, and the loading content was determined by UV-vis analysis to be 4 wt %. The DOX-loaded FA-DLSP micelles demonstrated a sustained release of DOX due to the hydrophobic interaction between the polymer core and the drug molecules. The hydrolytic degradation in vitro was monitored by weight loss and proton nuclear magnetic resonance spectroscopy to gain insight into the degradation mechanism of the FA-DLSP micelles. It was found that the degradation was pH-dependent and started from the hydrophilic shell gradually to the hydrophobic core. Flow cytometry and confocal microscope studies revealed that the cellular binding of the FA-DLSP hybrid against human KB cells with overexpressed folate-receptors was about twice that of the neat DLSP (without FA). The in vitro cellular cytotoxicity indicated that the FA-DLSP micelles (without DOX) had good biocompatibility with KB cells, whereas DOX-loaded micelles exhibited a similar degree of cytotoxicity against KB cells as that of free DOX. These results clearly showed that the FA-DLSP unimolecular micelles could be a promising nanosize anticancer drug carrier with excellent targeting property.     

嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束的制备及性质研究

目的：为构建聚合物胶束药物运载体系,制备嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束并测定其性质。方法：以L-天冬氨酸为原料,重氮化、环化后经开环聚合得到聚苹果酸苄基酯。氨基聚乙二醇通过酰胺键连接到β-聚苹果酸苄基酯上形成两亲性嵌段共聚物,喜树碱做药物模型制备载药胶束。动态光散射法测定胶束粒径、评价胶束稳定性,高效液相法测定喜树碱载药率和包封率,芘荧光法与动态光散射法测定临界胶束浓度。结果：喜树碱包封率72%,载药率6%,临界胶束浓度为40μg.mL-1。随着聚苹果酸苄基酯分子量减小,胶束稳定性增强。结论：聚乙二醇-聚苹果酸苄基酯在疏水链/亲水链分子量比值为2-4时在水中可自组装形成纳米胶束,可作为性能优良的聚合物药物载体。     

聚苹果酸- 聚乙二醇- 叶酸纳米共聚物的合成和生物活性的研究

目的:制备聚苹果酸-聚乙二醇-叶酸(PMLA-PEG-FA)纳米共聚物,为构建多功能靶向药物转运系统提供前期工作.方法:配体叶酸(FA)通过α-羟基-ω-醛基聚乙二醇(HO-PEG-CHO)以腙键连接在经过水合肼修饰的聚苹果酸的主链上.核磁共振光谱表征纳米共聚物的结构,动态透析法研究腙键响应不同pH值的断键特性,监测不同pH值共聚物中叶酸的稳定性.并采用SMCC-7721人体肝癌细胞测定该纳米共聚物的细胞毒性.结果:1、经核磁共振表征PMLA-PEG-FA共聚物合成完成.2、在pH5.5、pH6.5及pH7.4的PBS缓冲体系中,6h后配体叶酸累积释放率分别为88.1％,85.3％和41.6％.3、MTT实验证实PMLA-PEG-FA无毒性.结论:PMLA-PEG-FA有望成为智能靶向药物载体.     

Chitosan matrix with three dimensionally ordered macroporous structure for nimodipine release

Three dimensionally ordered macroporous (3DOM) chitosan (3D-CS) matrix with interconnected pores in the nanometer range was developed as a drug carrier for the first time. 3D-CS was prepared using a template-assisted assembly and characterized by SEM, TGA, N(2) adsorption and FT-IR. As a model drug, nimodipine (NMDP) was incorporated into the pores of 3D-CS matrix. The solid state properties of NMDP-loaded samples were characterized by SEM, XRD, DSC and FT-IR. Dissolution studies showed that release behavior of the drug was markedly affected by the particle size of the matrix. With a relatively small matrix particle size, formulations of NMDP-3D-CS-0.5 and NMDP-3D-CS-1 exhibited rapid release patterns. However, on increasing the amount of carrier, release rate of the drug decreased. The pH-dependent slow-release characteristic of 3D-CS matrix delivery system was demonstrated by investigating the release behavior of NMDP at different pH values.     

Hyperbranched double hydrophilic block copolymer micelles of poly(ethylene oxide) and polyglycerol for pH-responsive drug delivery

We report the synthesis of a well-defined hyperbranched double hydrophilic block copolymer of poly(ethylene oxide)-hyperbranched-polyglycerol (PEO-hb-PG) to develop an efficient drug delivery system. In specific, we demonstrate the hyperbranched PEO-hb-PG can form a self-assembled micellar structure on conjugation with the hydrophobic anticancer agent doxorubicin, which is linked to the polymer by pH-sensitive hydrazone bonds, resulting in a pH-responsive controlled release of doxorubicin. Dynamic light scattering, atomic force microscopy, and transmission electron microscopy demonstrated successful formation of the spherical core-shell type micelles with an average size of about 200 nm. Moreover, the pH-responsive release of doxorubicin and in vitro cytotoxicity studies revealed the controlled stimuli-responsive drug delivery system desirable for enhanced efficiency. Benefiting from many desirable features of hyperbranched double hydrophilic block copolymers such as enhanced biocompatibility, increased water solubility, and drug loading efficiency as well as improved clearance of the polymer after drug release, we believe that double hydrophilic block copolymer will provide a versatile platform to develop excellent drug delivery systems for effective treatment of cancer.     

Design of Magnetic Polymeric Particles as a Stimulus-Responsive System for Gastric Antimicrobial Therapy

The treatment of peptic ulcers induced by H. pylori remains challenging due to the deep mucous layer location of bacteria preventing antimicrobial drug access. The present work aimed to design and evaluate in vitro dual responsive (both pH and magnetic field-sensitive) polymeric magnetic particles loaded with amoxicillin as a smart drug carrier for deep mucous layer penetration and in situ drug release. Magnetite particles were produced by the co-precipitation method and subsequently coated with the Eudragit^®S100 and amoxicillin by using the spray-drying technique. The physicochemical characterization of the obtained particles was carried out by optical and scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry. Additionally, drug release tests and antibacterial activity tests were evaluated in vitro. Microparticles presented 17.2?±?0.4 μm in size and their final composition was 4.3?±?1.5% of amoxicillin, 87.0?±?2.3% of Eudragit, and 9.0?±?0.3% of magnetite. They were both pH and magnetic field responsive while presenting antimicrobial activity. On one side, magnetic field responsiveness of particles is expected to prompt them to reach bacterium niche in deep mucous layer by means of magnetic forces. On the other side, pH responsiveness is expected to enable drug release in the neutral pH of the deep mucous layer, preventing undesired delivery in the acidic gastric lumen. Smart microparticles were designed presenting both pH and magnetic field responsiveness as well as antimicrobial activity. These may be promising assets for peptic ulcer treatment.