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,24h内5-氟尿嘧啶累积释药量达36.2%,10d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。     

Effect of PEG conformation and particle size on the cellular uptake efficiency of nanoparticles with the HepG2 cells.

Core-shell nanoparticles were prepared from di-block copolymer of methoxy poly(ethylene glycol)-polycaprolactone (MePEG-PCL) and tri-block copolymer of polycaprolactone-poly(ethylene glycol)-polycaprolactone (PCL-PEG-PCL). The MePEG-PCL copolymers form nanoparticles with PEG "brush" on their surfaces and PCL-PEG-PCL copolymers form nanoparticles with a "mushroom-like" structure on their surfaces in aqueous solution. The morphology and size of nanoparticles were measured by field emission scanning electron microscopy (FESEM) and laser light scattering (LLS). All the nanoparticles are in spherical shape and the sizes are less than 200 nm. The sizes of the nanoparticles increases with increasing PCL segment length. The drug-loading content results showed that the optimal feeding ratio of paclitaxel to copolymer is dependent upon the copolymer composition and 5% is a suitable feeding ratio. The in vitro release behavior exhibits a sustained release manner and is affected by copolymer composition. Experimental results showed that cells would prefer to attach to more hydrophobic polymers. Comparing between MePEG-PCL and PCL-PEG-PCL of similar hydrophobicity, more HepG2 cells have attached to the MePEG-PCL copolymer films because a denser PEG layer was formed on the surfaces of PCL-PEG-PCL copolymers. In vitro cellular uptake experimental results indicated that HepG2 cells prefer smaller nanoparticles with the same PEG configuration on their surfaces. The cytotoxicity of paclitaxel-loaded nanoparticles seemed to increase with increasing drug loading of nanoparticles against HepG2 cells.     

Incorporation and release behavior of hydrophobic drug in functionalized poly(D,L-lactide)-block-poly(ethylene oxide) micelles.

The poly(ethylene oxide)-poly(lactide) (PEO-PLA) block copolymers containing a small quantity of carboxylic acid in the PLA block were synthesized. The microscopic characteristics of nanoparticles with carboxylic acid content in the copolymer were analyzed, and the effect of specific interactions between the copolymer and the model drug on the drug loading capacity and the release behavior were investigated systematically. The sizes of nanoparticles prepared by a dialysis method are within the range of 30-40 nm. The nanoparticles prepared from functionalized block copolymers have a very low critical micelle concentration (CMC) value as low as approximately 10(-3) mg/ml, which indicates a good stability of the nanoparticles in spite of the presence of carboxylic acid. The drug loading efficiency of nanoparticles dramatically increased when carboxylic acid content was increased in the block copolymer. This result may be attributed to the increase of interactions between the copolymer and the drug. The release rate of the drug was much slower from nanoparticles containing higher amounts of carboxylic acid in the copolymer, which might be associated with the enhanced interaction between the carboxylic group of copolymers and the drug. These experimental results suggest that the nanoparticles prepared from functionalized PEO-PLA block copolymers could be a good candidate for an injectable drug delivery carrier.     

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,24h内5-氟尿嘧啶累积释药量达36.2%,10d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。     

Synthesis, characterization of novel injectable drug carriers and the antitumor efficacy in mice bearing Sarcoma-180 tumor.

New unsaturated polyesters of poly(fumaric acid-glycol-dodecanedioic acid) P(FA-GLY-DDDA) copolymers, poly(fumaric acid-glycol-brassylic acid) P(FA-GLY-BA) copolymers, poly(fumaric acid-glycol-tetradecanedioic acid) P(FA-GLY-TA) copolymers and poly(fumaric acid-glycol-pentadecanedioic acid) P(FA-GLY-PA) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: fumaric acid, glycol and one of C(12-15) dibasic acids. The copolymers were characterized by FT-IR, gel permeation chromatography (GPC), and the surface structure of unsaturated polyesters after solidify were studied by atomic force microscopy (AFM). The molecular structure and composition of the unsaturated polyesters were determined by 1H NMR spectroscopy. In vitro studies showed that some of the copolymers are degradable in phosphate buffer at 37 degrees C and have properly drug release rate as drug carriers. The biocompatibility of P(FA-GLY-DDDA) and P(FA-GLY-BA) copolymers under mice skin was also evaluated, macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. Antitumor efficacy of P(FA-GLY-DDDA) copolymers and P(FA-GLY-BA) copolymers containing 5% adriamycin hydrochloride (ADM) in mice bearing Sarcoma-180 tumor exhibited increased volume doubling time (VDT) (22+/-1.5 days and 24+/-2.5 days) compared to plain subcutaneous injection of ADM (7+/-0.9 days). The antitumor efficacy of injecting P(FA-GLY-DDDA)-ADM inside tumor twice intervened in 22 days exhibited an especially increased cytotoxic effect as revealed by increased VDT (33+/-2.5 days), and the antitumor efficacy of injecting P(FA-GLY-BA)-ADM inside tumor twice intervened in 24 days exhibited an especially increased cytotoxic effect as revealed by increased VDT (35+/-1.5 days). The studies suggested that P(FA-GLY-DDDA) copolymers and P(FA-GLY-BA) copolymers as effective and injectable carriers for antineoplastic drug like adriamycin hydrochloride have a very good foreground in the treatment of noumenon tumor.     

Novel composite core-shell nanoparticles as busulfan carriers.

This study presents a method for the design of novel composite core-shell nanoparticles able to encapsulate busulfan, a crystalline drug. They were obtained by co-precipitation of mixtures of poly(isobutylcyanoacrylate) (PIBCA) and of a diblock copolymer, poly(epsilon-caprolactone)-poly(ethylene glycol) (PCL-PEG), in different mass ratios. The nanoparticle size, morphology and surface charge were assessed. The chemical composition of the top layers was determined by X-ray photo-electron spectroscopy (XPS). (3)H-labelled busulfan was used in order to determine the drug loading efficiency and the in vitro drug release by liquid scintillation counting. Physico-chemical techniques such as Zeta potential determination and XPS analysis provided evidence about a preferential surface distribution of the PCL-PEG polymer. Therefore, composite nanoparticles have a "core-shell"-type structure, where the "core" is essentially formed by the PIBCA polymer and the "shell" by the PCL-PEG copolymer. The use of PIBCA to form the core of the nanoparticles leads to a 2-4 fold drug loading increase, in comparison to the single PCL-PEG nanoparticles. In addition, the complement activation results showed a significant difference between the composite nanoparticles and the single PIBCA nanoparticles, thus demonstrating that PEG at the surface of the nanoparticles reduced the complement consumption. The PIBCA:PCL-PEG composite nanoparticles prepared using the new co-precipitation method here described represent an original approach for busulfan administration.     

Polymeric micelles of poly(2-ethyl-2-oxazoline)-block-poly(epsilon-caprolactone) copolymer as a carrier for paclitaxel.

Polymeric micelles based on amphiphilic block copolymers of poly(2-ethyl-2-oxazoline) (PEtOz) and poly(epsilon -caprolactone) (PCL) were prepared in an aqueous phase. The loading of paclitaxel into PEtOz-PCL micelles was confirmed by 1H-NMR spectra. Paclitaxel was efficiently loaded into PEtOz-PCL micelles using dialysis method, and the loading content of paclitaxel in micelles was in the range 0.5-7.6 wt.% depending on the block composition of block copolymers, organic solvent used in the dialysis, and feed weight ratio of paclitaxel to block copolymer. The higher the content of hydrophobic block in the block copolymers, the higher the loading efficiency of micelles for paclitaxel. When acetonitrile was used as solvent, a higher drug loading efficiency was obtained than with THF. The loading efficiency decreased with increasing feed weight ratio of paclitaxel to block copolymer from 0.1:1 to 0.2:1. The hydrodynamic diameters of paclitaxel-loaded micelles were in the range 18.3-23.4 nm with narrow size distribution. The hemolysis test of PEtOz-PCL performed in vitro indicated that the toxicity of PEtOz-PCLs to lipid membrane was not significant compared with Tween 80, and was comparable to that observed with Cremophore EL. The proliferation inhibition activity of paclitaxel-loaded micelles for KB human epidermoid carcinoma cells was also evaluated in vitro. Paclitaxel-entrapped polymeric micelles exhibited comparable activity to that observed with Cremophore EL-based paclitaxel formulations in inhibiting the growth of KB cells.     

Micellar carriers based on block copolymers of poly(epsilon-caprolactone) and poly(ethylene glycol) for doxorubicin delivery.

Diblock copolymers of poly(epsilon-caprolactone) (PCL) and monomethoxy poly(ethylene glycol) (MPEG) with various compositions were synthesized. The amphiphilic block copolymers self-assembled into nanoscopic micelles and their hydrophobic cores encapsulated doxorubicin (DOX) in aqueous solutions. The micelle diameter increased from 22.9 to 104.9 nm with the increasing PCL block length (2.5-24.7 kDa) in the copolymer composition. Hemolytic studies showed that free DOX caused 11% hemolysis at 200 microg ml(-1), while no hemolysis was detected with DOX-loaded micelles at the same drug concentration. An in vitro study at 37 degrees C demonstrated that DOX-release from micelles at pH 5.0 was much faster than that at pH 7.4. Confocal laser scanning microscopy (CLSM) demonstrated that DOX-loaded micelles accumulated mostly in cytoplasm instead of cell nuclei, in contrast to free DOX. Consistent with the in vitro release and CLSM results, a cytotoxicity study demonstrated that DOX-loaded micelles exhibited time-delayed cytotoxicity in human MCF-7 breast cancer cells.     

Release of anti-restenosis drugs from poly(ethylene oxide)-poly(DL-lactic-co-glycolic acid) nanoparticles.

Dexamethasone- or rapamycin-loaded nanoparticles based on poly(ethylene oxide) and poly(dl-lactic-co-glycolic acid) block copolymers (PEO-PLGA) were prepared without additional stabilizer using the salting-out method. A fast release of drug in PBS (pH 7.4) at 37 degrees C resulting in 100% release within 5 h was observed for both drugs. The rate of drug release was substantially reduced by treating the particles with gelatin or albumin after drug loading, resulting in a linear drug release in time. It was shown that the rate of drug release is related to the amount of protein associated with the nanoparticles. After gelatin treatment of drug-loaded nanoparticles, sustained release of dexamethasone for 17 days and of rapamycin for 50 days could be achieved.     

Poly(ethylene glycol)/poly(epsilon-caprolactone) diblock copolymeric nanoparticles for non-viral gene delivery: the role of charge group and molecular weight in particle formation, cytotoxicity and transfection.

Two types of nanoparticles containing pGL3-Control (plasmid DNA) were prepared using nonionic amphiphlic block copolymers and ionic amphiphilic block copolymers containing a terminal cationic group to investigate the effect of charge on the vehicle properties for systemic gene delivery. Methoxy poly(ethylene glycol) (MPEG)/poly(epsilon-caprolactone) (PCL) diblock copolymers were synthesized by the ring-opening polymerizatrion of epsilon-caprolactone in the presence of a catalyst-free MPEG homopolymer. The hydroxy groups of MPEG/PCL block copolymer were then modified into an amine group to synthesize an amine-terminated MPEG/PCL diblock copolymer (AMPEG/PCL). DNA was incorporated into the polymeric nanoparticles by physical entrapment and electrostatic interaction. All nanoparticle samples exhibited spherical structures and although their sizes increased slightly after DNA-loading, they remained less than 160 nm. The AMPEG/PCL nanoparticles exhibited smaller particle sizes than the MPEG/PCL nanoparticles of the same molecular weight after DNA-loading. The optimum mixing ratio of MPEG/PCL and AMPEG/PCL copolymers to DNA ranged from 4:1 to 1:2 depending on the molecular weight of the block copolymer, the composition of MPEG and PCL and terminal amine group. Based on in vitro cytotoxicity tests, the DNA-loaded MPEG/PCL and AMPEG/PCL nanoparticles did not induce any remarkable cytotoxicity against normal human fibroblasts. Transfection efficiencies of DNA-loaded nanoparticles were improved about 3.4 - 12.9 times under serum conditions.     

Indomethacin-loaded polymeric nanocarriers based on amphiphilic polyphosphazenes with poly (N-isopropylacrylamide) and ethyl tryptophan as side groups: Preparation, in vitro and in vivo evaluation.

The effects of copolymer composition, drug structure and initial drug feed on drug loading of polymeric micelles based on amphiphilic polyphosphazenes were investigated. It was found that the drug loading capacity of micelles based on this type of amphiphilic copolymers was mainly determined by copolymer composition and the chemical structure of drug. In addition to the compatibility between drug and micellar core, hydrogen bonding interaction between drug and hydrophilic corona may significantly influence drug loading as well. In vitro drug release in 0.1 M PBS (pH 7.4) suggested that indomethacin (IND) in the micelles was released through Fickian diffusion, and no significant difference in release rate was observed for micelles based on copolymers with various EtTrp content. Compared with in vitro IND release profile, in vivo pharmacokinetic study after subcutaneous administration provides a more sustained release behavior. Additionally, in comparison with free drug solution at the same dose, IND concentration in rat plasma showed a prolonged retention when the drug was delivered through polymeric micelles. In vivo pharmacodynamic study based on both carrageenan-induced acute and complete Freund's adjuvant-induced adjuvant arthritis model indicated that sustained therapeutic efficacy could be achieved through intraarticular injection of IND-loaded micelles. Most importantly, local delivery of IND can avoid the severe gastrointestinal stimulation, which was frequently associated with oral administration.     

载神经生长因子纳米药物体外诱导PCI2细胞的药效

背景：研究发现经表面修饰过的聚合物纳米粒能通过血脑屏障,可以改善药物对中枢神经系统疾病的疗效.目的：以生物可降解材料聚乙二醇-聚乳酸聚乙醇酸共聚物制备高包封率的载神经生长因子的纳米粒,并初步探讨其对PC12细胞的体外诱导效果评价. 方法：采用复乳化溶剂扩散法制备载牛血清白蛋白的聚乙二醇-聚乳酸聚乙醇酸共聚物纳米粒,用单因素分析及正交设计对工艺进行优化筛选;扫描电镜观察纳米粒形态;纳米粒分析仪测定平均粒径和分散指数;BCA法测定纳米粒包封率及载药量,并进一步研究纳米粒体外释放特性.得到最好的制备方案后,制备载神经生长因子的聚合物纳米粒,并以此处理PC12细胞,倒置荧光显微镜观察载神经生长因子的聚乙二醇-聚乳酸聚乙醇酸共聚物纳米粒对 PC12细胞的体外诱导状况,对其诱导效果、毒性及缓释效果进行评价. 结果与结论：最优处方制备的载牛血清蛋白的聚乙二醇-聚乳酸聚乙醇酸共聚物纳米粒呈球形、大小均匀,平均粒径（258.9±5.73） nm,包封率为（80.56±2.23）%,内水相中投药量10 mg 时载药量约（4.24±0.12）%,体外释放符合Higuchi方程,分初期突释释放和后期缓释释放2个阶段,0-56 d的累积释放总量分别为76.61%（牛血清白蛋白）、62.34%（神经生长因子）.载神经生长因子的聚乙二醇-聚乳酸聚乙醇酸共聚物纳米粒可以诱导PC12细胞像神经元样分化效能,表现出良好的缓释性能及无毒性作用.提示制备的载神经生长因子的聚乙二醇-聚乳酸聚乙醇酸共聚物纳米粒理化性质优良,在体外有良好的缓释效能及无毒性作用.     

Crosslinked poly(alkylene oxides) for the preparation of controlled release micromatrices

Poly(ethylene oxides) and block copolymers of ethylene oxide and propylene oxide were crosslinked by diisocyanates and multifunctional branching agents to form water-swellable, partially crystalline networks. The equilibrium weight swelling ratio of the samples was determined in water and benzyl alcohol. Solvent fractional uptake varying from about 0.2 to 19, relative to the dry material, was achieved. This wide sorption range allowed incorporation of large amounts of active agents with different solubility characteristics. Proxyphylline, theophylline and methylcatechin were incorporated into the hydrogels by soaking in benzyl alcohol solutions. The final systems were reduced to a particle size of 400–630 μm and their release behavior studied. Various preparation parameters, such as the molecular weight of the initial poly(ethylene oxide), the copolymer composition and the interlinking degree, influenced the delivery rate by means of a modified effective mesh size of the network. In addition, drug characteristics greatly affected their release, possibly due to drug-polymer interactions. Fickian drug delivery was observed from these micromatrix systems.     

Conjugates of poly(DL-lactic acid) with ethylenediamino or diethylenetriamino bridged bis(beta-cyclodextrin)s and their nanoparticles as protein delivery systems.

Some biodegradable amphiphilic copolymers were synthesized by conjugating poly(DL-lactic acid) (PLA) onto ethylenediamino or diethylenetriamino bridged bis(beta-cyclodextrin)s (bis-CDs). Double emulsion (DE) and nanoprecipitation (NP) methods were used to fabricate the nanoparticles of these copolymers entrapping bovine serum albumin (BSA) as a model protein. Effects of the experimental parameters, such as copolymer composition, BSA concentration, copolymer concentration and poly(vinyl alcohol) concentration, on particular size and encapsulation efficiency (EE) were investigated. Their EE to BSA could reach 83.5% at an optimized condition owing to the cooperative binding effect of the CD moiety with BSA. The core-corona structure of copolymer micelles fabricated from the nanoprecipitation was studied on the basis of 1H NMR and other measurements at various temperatures. The results showed that the core-corona structure kept stable below 50 degrees C (lower than Tg). And increase of the micelle association number occurred above the Tg because the size of the NPs became larger and proton signals of the liquid-like PLA cores could be observed in 1H NMR in D2O at 60 degrees C. The release profiles of NPs showed a burst effect followed by a continuous release. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, circular dichroic and fluorescence spectra were further used to identify the stability of BSA released from the NPs. The nanoparticles from the conjugates have a promising potential in nasal delivery system.     

PLGA-mPEG nanoparticles of cisplatin: in vitro nanoparticle degradation, in vitro drug release and in vivo drug residence in blood properties.

The in vitro nanoparticle degradation, in vitro drug release and in vivo drug residence in blood properties of PLGA-mPEG nanoparticles of cisplatin were investigated. The nanoparticles were prepared by a double emulsion method and characterized with regard to their morphology, size, zeta potential and drug loading. The rate of in vitro degradation of the PLGA-mPEG nanoparticles in PBS (pH 7.4) depended on their composition, increasing when the mPEG content (mPEG:PLGA ratio) of the nanoparticles increased. Sustained cisplatin release over several hours from the PLGA-mPEG nanoparticles in vitro (PBS) was observed. The composition of the nanoparticles affected drug release: the rate of release increased when the mPEG content of the nanoparticles increased. Within the range of drug loadings investigated, the drug loading of the nanoparticles did not have any significant effect on drug release. The loading efficiency was low and needs improvement in order to obtain PLGA-mPEG nanoparticles with a satisfactory cisplatin content for therapeutic application. The i.v. administration of PLGA-mPEG nanoparticles of cisplatin in BALB/c mice resulted in prolonged cisplatin residence in systemic blood circulation. The results appear to justify further investigation of the suitability of the PLGA-mPEG nanoparticles for the controlled i.v. delivery and/or targeting of cisplatin.     

Dependence of copolymer composition, swelling history, and drug concentration on the loading of diltiazem hydrochloride (DIL.HCl) into poly[(N-isopropylacrylamide)-co-(methacrylic acid)] hydrogels and its release behaviour from hydrogel slabs.

The loading of an antihypertensive cationic drug, diltiazem hydrochloride (DIL.HCl), into poly(N-isopropylacrylamide) [P(N-iPAAm)], poly(methacrylic acid) [P(MAA)], and their poly[(N-isopropylacrylamide)-co-(methacrylic acid)] P[(N-iPAAm)-co-(MAA)] hydrogels as well as their release behaviour have been investigated. For this purpose, two series of hydrogels have been tested, one previously soaked under acidic pH (treated hydrogels) and the other from the synthesis and washed in deionized water (untreated hydrogels). For the drug loading, these two series of hydrogels have been soaked in drug solutions with different concentrations. DIL.HCl amounts loaded by the gels as well as swelling degrees as a function of both hydrogel composition and DL.HCl concentration in the loading solution have been analyzed. Due to the interactions among DIL.HCl and the MAA group, "untreated" enriched MAA copolymer hydrogels present the highest drug load and loading efficiency. A DIL.HCl concentration of 320 microm/mL has been employed to load copolymers for release experiments, because for this concentration, hydrogels reach relative high drug load with a still high efficiency of loading. Release has been tested in three media, namely, fresh water (Milli-Q grade, pH 7.0), 0.1 N hydrogen chloride (pH 1.2), and a phosphate buffer (pH 7.0). In general, release is lower in fresh water and acidic media than in phosphate buffer. To explain these results, the effect of temperature, medium, and composition on the pH and thermo sensitivity of the hydrogels as well as the diltiazem-polymer interactions have been taken into account.     

Preparation of biodegradable cyclosporine nanoparticles by high-pressure emulsification-solvent evaporation process.

The cyclic endecapeptide cyclosporine (CsA), a potent immunosuppressive drug, was incorporated into biodegradable poly (DL-lactide-co-gylcolide) (DL-PLG) 50/50, 65/35 and PEG 5000-70/30 DL-PLG to improve the oral bioavailability and pharmacokinetics. Nanoparticles were prepared by a high-pressure emulsification-solvent evaporation (HPESE) process. The CsA-loaded nanoparticles were evaluated for particle size, zeta potential, surface morphology by scanning electron microscopy (SEM), thermal characterizations by differential scanning calorimetry (DSC), encapsulation efficiency (E.E.%) and in vitro release. The amount of CsA loaded into the nanoparticles was determined using high-performance liquid chromatography (HPLC) at a detection wavelength of 210 nm. The mobile phase was acetonitrile-water (70:30% v/v) and flow rate was set at 1.5 ml min(-1). The photon correlation spectroscopy showed that the particles size were <250 nm and polydispersity index (PI) <0.14. The zeta potential was positive for 200 mg and negative for 400 mg of polymer composition, respectively. The SEM micrographs revealed that the nanoparticles were spherical and smooth. The drug loading was between 82% and 92%. Differential scanning calorimetry (DSC) studies did not show the melting endotherm for CsA in the drug-loaded nanoparticles. In-vitro release in intestinal fluid pH 6.8 (USP XXIV) showed a cumulative percent release of 30-45% CsA in 8 h. The physicochemical properties showed that the DL-PLG and PEG-DLPLG nanoparticles could be an effective carrier for oral CsA delivery. The reported method is easy, reproducible and can be automated for batch scale production.     

磁性聚乳酸-羟基乙酸氧化酚砷纳米微粒的制备及其特性

背景:基于纳米技术发展起来的纳米载体介导的磁性载药系统,在外加磁场作用下,能实现位点特异性靶向给药的目的,有利于提高病灶部位的局部药物浓度,从而进一步提高治疗效果,减少全身毒副作用.目的:研究磁性聚乳酸-羟基乙酸氧化酚砷纳米微粒的制备工艺,评价纳米粒子特性.设计:首先选择几个可能影响纳米微粒特性的因素进行了单因素实验,然后再根据实验结果,结合统计学中的正交设计,获得了最佳优化处方.单位:解放军第二军医大学长海医院特诊科.材料:实验于2005-01/2006-03在解放军第二军医大学药学院药剂教研室完成.实验用氧化酚砷购自美国Sigma公司,聚乳酸-羟基乙酸由山东医疗器械研究所提供,纳米级四氧化三铁购自美国Sigma公司,聚乙烯醇购自北京有机化工厂,二氯甲烷等其他试剂均为分析纯,购于上海国药集团化学试剂有限公司.方法:运用超声乳化-溶剂挥发法制备磁性聚乳酸-羟基乙酸氧化酚砷纳米微粒,通过透射电镜观察微粒形态,振动样品磁强计确证纳米微粒磁性的存在,激光粒径仪测定纳米粒的粒径大小和分布,高效液相法测定氧化酚砷的载药量及包封率,并计算氧化酚砷体外释放百分率.主要观察指标:磁性聚乳酸-羟基乙酸氧化酚砷纳米微粒的形态、粒径、载药量、包封率、磁性及体外释放情况.结果:①微粒包封率和载药量:实验制备的纳米粒平均包封率为34.2%;5批纳米粒载药量分别为3.06%,3.15%,3.18%,3.21%,3.41%,平均载药量为3.20%,批间差异较小,说明工艺稳定性、重现性好.②微粒形态:纳米微粒呈圆形,表面光滑,分布均匀,不粘连,磁性微球中可见非均匀分散的黑色不透光区,为四氧化三铁微粒.③微粒粒径:分布范围窄(140～500 nm),平均290 nm.④微粒磁性:在不断改变外加磁场的大小与方向的情况下,微粒具有不同的磁化强度,说明氧化酚砷聚乳酸纳米微粒具有一定的磁响应性.⑤体外释放实验:氧化酚砷经过最初的快速释放后,进入缓慢控释阶段,于第8天时达到最终基本稳定的平台期.结论:实验获得了较满意的磁性聚乳酸-羟基乙酸氧化酚砷纳米微粒制备工艺;该纳米微粒在外加磁场的情况下有较好磁靶向性的作用,同时具备良好药物缓释作用.     

肽功能化载GOD智能响应型相变纳米粒用于乳腺癌超声诊疗的实验研究

目的制备一种肿瘤归巢穿膜肽tLyp-1介导的载葡萄糖氧化酶（GOD）和全氟正戊烷（PFP）纳米粒（tLyp-1-GOD@PFP NPs），观察其基本表征、体内外超声成像以及对人乳腺癌MDA-MB-231细胞的体外靶向及体内外抗肿瘤能力。 方法采用乳化法制备tLyp-1-GOD@PFP NPs，观察其形态特点，检测其理化性质（粒径、电位、包封率、释药率）；低强度聚焦超声（LIFU）辐照纳米粒后，光镜下观察其相变情况，并观察其体内外超声成像效果；激光共聚焦显微镜和流式细胞仪检测纳米粒对MDA-MB-231细胞的靶向能力；使用CCK-8法和流式法评估在LIFU辐照下该纳米粒对MDA-MB-231细胞的抗肿瘤能力；通过荷瘤裸鼠尾静脉注射纳米粒并观察肿瘤体积变化和裸鼠体重以探索其体内抑瘤效果。 结果制备的纳米粒呈球形壳核结构，大小均一，其平均粒径为（227.4±12.5）nm，平均电位为（-16.5±2.7）mV，GOD的包封率为（12.93±0.46）%，载药率为（1.62±0.06）%，24 h释药率可达（51.73±3.22）%。光镜下相变和体外超声成像具有辐照时间依赖性。CCK-8和流式细胞仪检测结果证明tLyp-1-GOD@PFP NPs具有良好的生物安全性，并且在LIFU辐照后其抑瘤效果较好。同时，体内实验证实该纳米粒具有良好的超声造影能力和靶向能力，体内治疗结果也表明该纳米粒可有效抑制肿瘤增殖。 结论本研究成功制备了tLyp-1介导的载GOD和PFP的相变型纳米粒，对MDA-MB-231细胞具有特异靶向能力，在LIFU辐照下，可实现体内外超声成像，同时产生良好的抗肿瘤效果。     

Influence of formulation parameters on the characteristics of poly(D, L-lactide-co-glycolide) microspheres containing poly(L-lysine) complexed plasmid DNA.

This study describes the influence of polymer type, surfactant type/concentration, and target drug loading on the particle size, plasmid DNA (pDNA) structure, drug loading efficiency, in vitro release, and protection from DNase I degradation of poly(D, L-lactide-co-glycolide) (PLGA) microspheres containing poly(L-lysine) (PLL) complexed pDNA. PLGA microspheres containing pDNA-PLL were prepared using the water-in-oil-in-water (w-o-w) technique with poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) as surfactants in the external aqueous phase. A complex ratio of 1:0.33 (pDNA-PLL, w/w) enhanced the stability of pDNA during microsphere preparation. Higher pDNA-PLL loading efficiency (46.2%) and supercoiled structure (64.9%) of pDNA were obtained from hydrophobic PLGA (M(w) 31000) microspheres compared with hydrophilic PLGA or low-molecular-weight PLGA microspheres. The particle size decreased from 6.6 to 2.2 microm when the concentration of PVA was increased from 1 to 7%. At the same concentration of surfactant, PVA stabilized microspheres showed higher pDNA-PLL loading efficiency (46.2%) than PVP stabilized microspheres (24.1%). Encapsulated pDNA in PLGA microspheres was protected from enzymatic degradation and maintained in the supercoiled form. The pDNA-PLL microspheres showed in vitro release of 95.9 and 84.9% within 38 days from the low-molecular-weight PLGA and hydrophilic PLGA microspheres, respectively, compared to 54.2% release from the hydrophobic, higher-molecular-weight PLGA microspheres. The results suggest loading and release of pDNA-PLL complex can be influenced by surfactant concentration and polymer type.