Self-Assembled Biodegradable Nanoparticles Developed by Direct Dialysis for the Delivery of Paclitaxel

Purpose The main objective of this study was to obtain self-assembled biodegradable nanoparticles by a direct dialysis method for the delivery of anticancer drug. The in vitro cellular particle uptake and cytotoxicity to C6 glioma cell line were investigated. Methods Self-assembled anticancer drugs—paclitaxel-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(l-lactic acid) (PLA) nanoparticles—were achieved by direct dialysis. The physical and chemical properties of nanoparticles were characterized by various state-of-the-art techniques. The encapsulation efficiency and in vitro release profile were measured by high-performance liquid chromatography. Particle cellular uptake was studied using confocal microscopy, microplate reader, and flow cytometry. In addition, the cytotoxicity of this drug delivery system was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on C6 glioma cell line to predict the possible dose response of paclitaxel-loaded PLGA and PLA nanoparticles. Results PLGA and PLA nanoparticles with or without vitamin E tocopherol polyethylene glycol succinate (TPGS) as an additive were obtained, in which the sustained release of paclitaxel of more than 20 days was achieved. The coumarin6-loaded PLGA and PLA nanoparticles could penetrate the C6 glioma cell membrane and be internalized. The cytotoxicity of paclitaxel-loaded nanoparticles seemed to be higher than that of commercial Taxol? after 3 days incubation when paclitaxel concentrations were 10 and 20 μg/ml. Conclusions Direct dialysis could be employed to achieve paclitaxel-loaded PLGA and PLA nanoparticles, which could be internalized by C6 glioma cells and enhance the cytotoxicity of paclitaxel because of its penetration to the cytoplasm and sustained release property.     

Cytotoxicity of Paclitaxel Incorporated in PLGA Nanoparticles on Hypoxic Human Tumor Cells

Purpose  The aim of this work was to prepare paclitaxel-loaded PLGA nanoparticles and determine cytotoxicity of released paclitaxel for two hypoxic human tumor cell lines: breast carcinoma (MCF-7) and carcinoma cervicis (HeLa). Methods  Poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles containing paclitaxel were prepared by o/w emulsification-solvent evaporation method. Physicochemical characteristics of nanoparticles were studied. Cellular uptake of nanoparticles was evaluated by transmission electronic microscopy and fluorescence microscopy. Flow cytometry quantified the number of cells held in G₂/M phase. Cell viability was determined by the ability of single cell to form colonies. Biodistribution of nanoparticles in mice was evaluated by fluorescence microscopy. Results  The nanoparticles were spherical with average diameter 318 ± 5.1 nm. The encapsulation efficiency was 88.52%. The drug release profile in vitro exhibited a biphasic pattern. Cellular uptake was observed. Co-culture of tumor cells with paclitaxel-loaded nanoparticles demonstrated that released paclitaxel retained its bioactivity to block cells in G₂/M phase. Paclitaxel-loaded nanoparticles exhibited cytotoxic effect on both hypoxic MCF-7 and HeLa cells and its cytotoxicity was more significant than that of free paclitaxel. Fluorescent nanoparticles were mainly distributed to liver and spleen of mice. Conclusions  Paclitaxel-loaded PLGA nanoparticles may be considered a promising drug delivery system to eradicate hypoxic tumor cells. Cheng Jin and Ling Bai contributed equally to this work.     

Biodegradable films developed by electrospray deposition for sustained drug delivery

The objective of present study is to develop biodegradable films with controllable thickness for sustained release applications using a combination of electrospray deposition techniques. The model anticancer drug-paclitaxel is encapsulated inside PLGA films. The morphology observed by atomic force microscopy and scanning electron microscopy reveals that the film has a flat surface together with a dense structure. X-ray photo-electron spectroscopy results show that some amount of paclitaxel is found on the surface layer of films. X-ray diffractometry (XRD) analysis suggests that paclitaxel is in an amorphous form in the polymer matrix even for up to 30% drug loading. Differential scanning calorimetry (DSC) study further proved that paclitaxel is in a solid solution state in polymer films. In vitro release profile indicates that sustained release of paclitaxel from the films is for more than 85 days, without the tri-phasic release profile typically for PLGA films. The phase contrast images clearly suggests a slight decrease in the number of C6 glioma cells as the paclitaxel loading within the polymeric films is increased. The results of MTT assay employed to quantify the cell viability correlates well with the observation from phase contrast microscopy.     

The characterization of paclitaxel-loaded microspheres manufactured from blends of poly(lactic-co-glycolic acid) (PLGA) and low molecular weight diblock copolymers

Paclitaxel-loaded biodegradable drug delivery systems manufactured from poly(lactic-co-glycolic acid) (PLGA) are known to release the drug at extremely slow rates. The objective of this study was to characterize paclitaxel-loaded microspheres composed of blends of PLGA with low molecular weight ampipathic diblock copolymers. The encapsulation and release of a series of poly(epsilon-caprolactone) (PCL)- or poly(D,L-lactic acid) (PDLLA)-co-methoxypolyethylene glycol (MePEG) diblock copolymers was measured using quantitative gel permeation chromatography. Polymeric miscibility was determined by glass transition temperature measurements using differential scanning calorimetry and paclitaxel release was measured using HPLC methods. The PCL- and PDLLA-based diblock copolymers encapsulated at high efficiency and were miscible in PLGA microspheres (30-120m microm size range). The burst phase of paclitaxel release was increased up to 20-fold by the inclusion of diblock copolymers in PLGA microspheres. Approximately 10% of the more hydrophobic PCL-based copolymers released from the microspheres in a short burst over 3 days followed by very slow release over the following 10 weeks. Only the PDLLA-based copolymer released from the PLGA microspheres in a controlled manner over 10 weeks. All microspheres containing PEG were found to have more hydrophilic surfaces (as measured by contact angle) with improved biocompatibility (reduced neutrophil activation) compared to PLGA only microspheres. These results indicate that low molecular weight polyester-based diblock copolymers may be effectively encapsulated in PLGA microspheres to increase paclitaxel release (probably through a micellization process) and improve biocompatibility.     

Poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles prepared by high pressure homogenization for paclitaxel chemotherapy

High pressure homogenization was employed in the current work to prepare poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) for controlled release of paclitaxel. The prepared drug-loaded PLGA NPs were found of spherical shape with a size of 200-300 nm. The drug encapsulation efficiency ranged from 34.8+/-1.6 to 62.6+/-7.9% depending on the homogenization pressure and cycles. Paclitaxel was released from the nanoparticles in a biphasic profile with a fast release rate in the first 3 days followed by a slow first-order release. A higher or comparable cytotoxicity against glioma C6 cells was found for the drug formulated in the PLGA NPs in comparison with the free drug Taxol. Confocal laser scanning microscopy (CLSM) evidenced internalization of the fluorescent coumarin 6-loaded PLGA NPs by the C6 cells. The freeze-dried nanoparticles were found to possess excellent water redispersability. The high pressure homogenization could be applied for large industrial scale production of nanoparticles for drug delivery.     

Hydrogel Matrix Entrapping PLGA-Paclitaxel Microspheres: Drug Delivery with Near Zero-Order Release and Implantability Advantages for Malignant Brain Tumour Chemotherapy

Purpose

To develop paclitaxel-delivering PLGA microspheres entrapped in a gel matrix with sustained drug release properties and implantability advantages for local glioma chemotherapy.

Methods

Paclitaxel-loaded PLGA microspheres were fabricated using electrohydrodynamic atomization and entrapped by electrospray and gelation. The physicochemical characterizations were performed using scanning electron microscopy and differential scanning calorimetry. The influence of various parameters on the disintegration time was investigated. In vitro release of paclitaxel was quantified using high performance liquid chromatography. Cytotoxicity of the formulations was assessed by the quantification of IC₅₀ and caspase-3 activity against C6 glioma cells in vitro. The formulations were tested against a subcutaneous C6 glioma tumour in mice.

Results

Highly monodisperse gel beads containing a uniform microsphere distribution were obtained. Gelation using Ca²⁺ ions ensured entrapment of microspheres with high loading efficiency. With an increase in the gelation time, gelling bath concentration and decrease in microsphere loading, it was more difficult to disintegrate the beads and release the microspheres. The formulations demonstrated sustained drug release for more than 60 days at a near-constant rate and a low initial burst. Cell culture studies proved the cytotoxicity against C6 glioma and improved performance in comparison to Taxol®. The formulations could reduce subcutaneous tumour volume to a greater extent compared to Taxol® and the control.

Conclusions

Paclitaxel-loaded PLGA microspheres entrapped in an alginate gel matrix could be potential local chemotherapy implants to treat malignant glioma with critical advantages of implantability and sustained drug release with low initial burst.

     

Preparation and testing of cefquinome-loaded poly lactic-co-glycolic acid microspheres for lung targeting

The aim of this study was to prepare cefquinome-loaded poly lactic-co-glycolic acid (PLGA) microspheres and to evaluate their in vitro and in vivo characteristics. Microspheres were prepared using a spry drier and were characterized in terms of morphology, size, drug-loading coefficient, encapsulation ratio and in vitro release. The prepared microspheres were spherical with smooth surfaces and uniform size (12.4?±?1.2?μm). The encapsulation efficiency and drug loading of cefquinome was 91.6?±?2.6 and 18.3?±?1.3%, respectively. In vitro release of cefquinome from the microspheres was sustained for 36?h. In vivo studies identified the lung as the target tissue and the region of maximum cefquinome release. A partial lung inflammation was observed but disappeared spontaneously as the microspheres were removed through in vivo decay. The sustained cefquinome release from the microspheres revealed its applicability as a drug delivery system that minimized exposure to healthy tissues while increasing the accumulation of therapeutic drug at the target site. These results indicated that the spray-drying method of loading cefquinome into PLGA microspheres is a straightforward method for lung targeting in animals.     

Modified Paclitaxel-loaded Nanoparticles for Inhibition of Hyperplasia in a Rabbit Arterial Balloon Injury Model

Purpose This study tested the possibility of localized intravascular infusion of positive charged paclitaxel-loaded nanoparticles (NPs) to better prevent neointimal formation in a rabbit carotid artery injury model. Materials and Methods NPs were prepared by oil–water emulsion/solvent evaporation technique using biodegradable poly (lactide-co-glycolide) (PLGA). A cationic surfactant, didodecyldimethylammonium bromide (DMAB), was absorbed on the NP surface by electrostatic attraction between positive and negative charges. NPs were characterized in such aspects as size, surface morphology, surface charges as well as in vitro drug release profile. Balloon injured rabbit carotid arteries were treated with single infusion of paclitaxel-loaded NP suspension and observed for 28 days. The inhibitory effects of NPs on neointima formation were evaluated as end-point. Results NPs showed spherical shape with a diameter ranging from 200 to 500 nm. Negatively charged PLGA NPs shifted to positive after the DMAB modification. The in vitro drug release profile showed a biphasic release pattern. Morphometric analyses on the retrieved artery samples revealed that the inhibitory effect of intima proliferation was dose-dependent. At a concentration of 30 mg ml⁻¹, NP infusion completely inhibited intima proliferation in a rabbit vascular injury model. Conclusions Paclitaxel-loaded NPs with DMAB modification were proven an effective means of inhibiting proliferative response to vascular injury in a rabbit model.     

Improvement of survival in C6 rat glioma model by a sustained drug release from localized PLGA microspheres in a thermoreversible hydrogel

A local drug delivery system based on sustained drug release is an attractive approach to treat brain tumors. We have developed a novel device using drug-incorporated poly(lactic-co-glycolic acid) (PLGA) microspheres embedded in thermoreversible gelation polymer (TGP) formulation (drug/PLGA/TGP formulation). TGP forms a gel at body temperature but sol at room temperature. Therefore, when this formulation is injected into the brain tumor, the PLGA microspheres in TGP gel are localized at the injection site and do not diffuse throughout the brain tissue; eventually, sustained drug release from PLGA microspheres is achieved at the target site. In this study, two chemotherapeutic drugs (camptothecin (CPT) or vincristine (VCR)) were incorporated into PLGA microspheres to prepare drug/PLGA/TGP formulations. VCR/PLGA microspheres exhibited the higher encapsulation efficiency than CPT/PLGA microspheres (70.1% versus 30.1%). In addition, VCR/PLGA microspheres showed a higher sustained release profile than CPT/PLGA microspheres (54.5% versus 72.5% release, at 28 days). Therapeutic effect (mean survival) was evaluated in the C6 rat glioma model (control group, 18 days; CPT/PLGA/TGP treatment group, 24 days; VCR/PLGA/TGP treatment group, 33 days). In particular, the VCR/PLGA/TGP formulation produced long-term survivors (>60 days). Therefore, this formulation can be therapeutically effective formulation for the glioma therapy.     

Enhanced Oral Paclitaxel Bioavailability After Administration of Paclitaxel-Loaded Lipid Nanocapsules

Purpose The aim of this study was to evaluate the pharmacokinetics of paclitaxel-loaded lipid nanocapsules (LNC) in rats to assess the intrinsic effect of the dosage form on the improvement of paclitaxel oral exposure. Methods Paclitaxel-loaded LNC were prepared and characterized in terms of size distribution, drug payload, and the kinetics of paclitaxel crystallization. Taxol?, Taxol? with verapamil, or paclitaxel-loaded LNC were administered orally to rats. The plasma concentration of paclitaxel was determined using liquid chromatography mass spectrometry. Results The average size of LNC was 60.9 ± 1.5 nm. The drug payload of paclitaxel was 1.91 ± 0.01 mg/g of aqueous dispersion. The encapsulation efficiency was 99.9 ± 1.0%, and 1.7 ± 0.1% of paclitaxel was crystallized after 24 h. The oral bioavailability of Taxol? alone was 6.5%. After oral administration of paclitaxel-loaded LNC or paclitaxel associated with verapamil, the area under the plasma concentration–time curve was significantly increased (about 3-fold) in comparison to the control group (p < 0.05). Conclusions The results indicated that LNC provided a promising new formulation to enhance the oral bioavailability of paclitaxel while avoiding the use of pharmacologically active P-gp inhibitors, such as verapamil.     

Development of a novel morphological paclitaxel-loaded PLGA microspheres for effective cancer therapy: in vitro and in vivo evaluations

Sustained release of therapeutic agents into tumor cells is a potential approach to improve therapeutic efficacy, decrease side effects, and the drug administration frequency. Herein, we used the modified double-emulsion solvent evaporation (DSE) method to prepare a novel morphological paclitaxel (PTX) loaded poly(lactide-co-glycolide) (PLGA) microspheres (MS). The prepared rough PTX-PLGA-MS possessed microporous surface and highly porous internal structures, which significantly influenced the drug entrapment and release behaviors. The rough MS with an average particle size of 53.47?±?2.87?μm achieved high drug loading (15.63%) and encapsulation efficiency (92.82%), and provided a favorable sustained drug release. The in vitro antitumor tests of flow cytometry and fluoroimmunoassay revealed that the rough PTX-PLGA-MS displayed effective anti-gliomas activity and enhanced the cellular PTX uptake through adsorptive endocytosis. Both in vitro and in vivo antitumor results demonstrated that the sustained-release PTX could induce the microtubules assembly and the over-expression of Bax and Cyclin B1 proteins, resulting in the microtubule dynamics disruption, G2/M phase arrest, and cell apoptosis accordingly. Furthermore, as the rough PTX-PLGA-MS could disperse and adhere throughout the tumor sites and cause extensive tumor cell apoptosis with one therapeutic course (12?days), they could reduce the system toxicity and drug administration frequency, thus achieving significant tumor inhibitory effects with rapid sustained drug release. In conclusion, our results verified that the rough PTX-PLGA-MS drug release system could serve as a promising treatment to malignant glioma.     

Sustained release of low molecular weight heparin from PLGA microspheres prepared by a solid-in-oil-in-water emulsion method

Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres for the sustained release of low molecular weight heparin (LMWH) were prepared by a soild-in-oil-in-water (s/o/w) emulsion method. Prior to encapsulation, the LMWH micro-particles were fabricated by a modified freezing-induced phase separation method. The micro-particles were subsequently encapsulated into PLGA microspheres. Process optimization revealed that the NaCl concentration in the outer phase of s/o/w emulsion played a critical role in determining the properties of the microspheres. When the NaCl concentration increased from 0% to 5%, the encapsulation efficiency significantly increased from 51.5% to 76.8%. The initial burst release also decreased from 37.3% to 12.4%. In vitro release tests showed that LMWH released from PLGA microspheres in a sustained manner for about 14 days. Single injection of LMWH-loaded PLGA microspheres into rabbits resulted in an elevation of an anti-factor Xa activity for about 6 days. Furthermore, the integrity of the encapsulated LMWH was preserved during encapsulation process.     

表面修饰紫杉醇纳米粒局部给药抑制血管再狭窄的研究

制备表面修饰紫杉醇纳米粒并观察其抑制兔颈动脉损伤模型新生内膜增生的效果。采用超声乳化-溶剂挥发法制备载紫杉醇纳米粒，用物理吸附法对纳米粒进行表面修饰。对纳米粒进行表征，包封率和体外释放使用高效液相色谱仪进行分析。建立兔颈动脉损伤模型，在血管局部灌注不同浓度的修饰纳米粒。28天后，取出局部给药的颈动脉血管，进行苏木素-伊红(Hematoxylin & Eosin staining，HE)染色和弹力纤维染色。制备的载紫杉醇纳米粒粒径300 nm左右、包封率80%以上且表面带正电荷。体外药物释放呈两相释放。28天后，血管内局部灌注紫杉醇纳米粒悬液可有效抑制血管内皮增生，并呈剂量依赖性。浓度达到30 mg·mL^-1时，可完全抑制血管内膜增生。血管内局部灌注正电荷修饰的紫杉醇纳米粒悬液可有效抑制血管内皮增生，抑制效果随纳米粒悬液浓度的增加而提高。     

β-methasone-containing biodegradable poly(lactide-co-glycolide) acid microspheres for intraarticular injection: effect of formulation parameters on characteristics and in vitro release

A sustained drug release system based on the injectable poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with β-methasone was prepared for localized treatment of rheumatic arthritis. The microscopy and structure of microspheres were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR). The effects of various formulation parameters on the properties of microspheres and in vitro release pattern of β-methasone were also investigated. The results demonstrated that increase in drug/polymer ratio led to increased particle size as well as drug release rate. Increase in PLGA concentration led to increased particle size, but decreased burst release. The drug encapsulation efficiency increased sharply by increasing polyvinyl alcohol (PVA) concentration in the aqueous phase from 1.5 to 2.0%. β-methasone release rate decreased considerately with decreasing OP (organic phase)/AP (aqueous phase) volume ratio. Stirring rate had significantly influence on the particle size and encapsulation efficiency. Independent of formulation parameters, β-methasone was slowly released from the PLGA microspheres over 11 days. The drug release profile of high drug loaded microspheres agree with Higuchi equation with a release mechanism of diffusion and erosion, that of middle drug loaded microspheres best agreed with Hixcon-Crowell equation and controlled by diffusion and erosion as well. The low drug loaded microspheres well fitted to logarithm normal distribution equation with mechanism of purely Fickian diffusion.     

Formulation,development, and performance evaluation of metoclopramide HCl oro-dispersible sustained release tablet

The present study was undertaken to develop and evaluate an oro-dispersible, sustained release tablet of metoclopramide HCl. The technology was comprised of developing sustained release microparticles, and compression of resultant microspheres into a fast dispersible tablet by direct compression. The microspheres of metoclopramide HCl were prepared by an emulsification-solvent evaporation method using ethylcellulose as the matrix polymer. The prepared microspheres were evaluated for morphology, particle size, entrapment efficiency, and in vitro drug release characteristics. Scanning electron microscopy demonstrated spherical particles with a mean diameter of 81.27 ± 5.87 μm and the drug encapsulation efficiency was found to be 70.15 ± 3.06%. The process and formulation variables such as rotation speed, polymer concentration, and drug concentration influenced the drug encapsulation efficiency and in vitro drug release. Optimized microspheres were compressed into tablets which were comprised of metoclopramide HCl microspheres, 53% (w/v) of D-mannitol granules, 7% (w/w) of Polyplasdone XL 10, and 0.5% (w/w) of calcium stearate. The tablets demonstrated a hardness of 59 ± 3 N, friability of 0.21% and disintegration time of 27 ± 3 sec. The formulations were subjected to stability studies as per ICH guidelines and were found to be stable after a 6 month study. In vivo experiments conducted in rats demonstrated that a constant level of metoclopramide HCl in plasma could be maintained for up to 20 h at a suitable concentration for antiemetic activity. An appropriate combination of excipients made it possible to obtain orally disintegrating sustained release tablets of metoclopramide HCl using simple and conventional techniques.     

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     

Design and Development of a Novel Controlled Release PLGA Alginate-Pectinate Polyspheric Drug Delivery System

A 23 full factorial design was employed to evaluate and optimize the drug entrapment efficiency and in vitro drug release from PLGA microparticles encapsulated in a complex crosslinked alginate-pectinate matrix (polysphere). The independent formulation variables included the volume of internal and external phases, and concentration of PLGA. Surface morphology and internal structure of PLGA microparticles and polyspheres were examined by scanning electron microscopy which revealed spherical PLGA microparticles with highly porous surfaces that accounted for the rapid burst effect of this system. Texture analysis was used to profile the matrix resilience, tolerance, and energy absorbed. In vitro drug release was assessed in buffer media on PLGA microparticles and polyspheres. Polyspheres exhibited ideal zero-order release while PLGA microparticles had a burst effect followed by lag phase. Kinetic modeling of in vitro drug release data indicated that formulations were not highly dependent on polymeric erosion as a mechanism for drug release but rather diffusion. A close correlation existed between the matrix tolerance and energy absorbed. Formulations with decreased tolerance absorbed less energy, thus led to rapid surface erosion, lower matrix integrity and hence a burst effect. The converse was true for an increased matrix tolerance, which led to zero-order release supported by superior matrix integrity and a significantly reduced burst effect. The rat subcutaneous model validated in vitro release data and demonstrated that the polyspheres provided flexible yet superior rate-modulated drug delivery.     

Enhanced oral paclitaxel bioavailability after administration of paclitaxel-loaded nanosponges

The aim of this study was to evaluate the pharmacokinetics of paclitaxel-loaded nanosponges (PLN) in rats. The study also evaluates the intrinsic effect of the dosage form on the improvement of paclitaxel oral bioavailability. Paclitaxel-loaded nanosponges were prepared and characterized in terms of size distribution, drug solubilization, and the kinetics of paclitaxel sedimentation. Taxol^® and paclitaxel-loaded nanosponges were administered orally to rats. The plasma concentration of paclitaxel was determined using liquid chromatography. The average size of PLN was 350?±?25?nm. The drug payload of paclitaxel was 500?±?0.27?mg/g of lyophilized powder. The encapsulation efficiency was 99.1?±?1.0%, and 1.7?±?0.2% of paclitaxel was crystallized after 48?h. The relative oral bioavailability of paclitaxel-loaded nanosponges was 256. After oral administration of paclitaxel-loaded PLN, the area under the plasma concentration time curve was significantly increased (～ 3-fold) in comparison to the control group (p?<?0.05). The results indicated that PLN provided a promising new formulation to enhance the oral bioavailability of paclitaxel while avoiding the use of cremophore El: Ethanol in Taxol^®.     

Synthesis of high loading and encapsulation efficient paclitaxel-loaded poly(n-butyl cyanoacrylate) nanoparticles via miniemulsion

The manufacture of stable paclitaxel-loaded poly(n-butyl cyanoacrylate) (PBCA) nanoparticles containing high loading and encapsulation efficiency simultaneously were achieved in the presence of pluronic F127 via miniemulsion. It was found that both drug loading and encapsulation efficiencies of PBCA nanoparticles prepared by miniemulsion were higher (approximately three times) than those obtained by emulsion with similar paclitaxel content in the feed monomer (1%, w/w). Furthermore, the loading and encapsulation efficiencies increased concurrently (to a maximum of 4 and 80%, respectively) with increasing paclitaxel content and these nanoparticles were spherical in shape and with size near 100 nm. XRD patterns revealed that paclitaxel in particles was distributed in the molecular or amorphous state or in the form of small crystals. The in vitro drug release profile of drug-loaded PBCA nanoparticles prepared from miniemulsion exhibited a gradual release; more than 80% (w/w) of the paclitaxel was released after 96 h.     

葫芦素B-聚乳酸-羟基乙酸共聚物载药纳米粒的构建与药效学评价

目的 以聚乳酸-羟基乙酸共聚物（PLGA）作为纳米制剂载体材料将葫芦素B制备成纳米粒,并考察其对HepG2肝癌细胞的抑制效果。方法 使用乳化溶剂蒸发法制备葫芦素B-PLGA载药纳米粒,以PLGA浓度（X₁）、PVA浓度（X₂）和药物浓度（X₃）作为考察因素,以载药纳米粒的粒径大小（Y₁）和包封率（Y₂）作为评价指标,应用中心复合设计-效应面法优化葫芦素B-PLGA载药纳米粒处方;测定了纳米粒的粒径分布和Zeta电位值,通过透射电镜观察其微观形态,并考察了葫芦素B-PLGA载药纳米粒的体外药物释放特性;比较了葫芦素B与葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制效果。结果 葫芦素B-PLGA载药纳米粒的最优处方组成为：PLGA浓度为9.0%,PVA浓度为2.0%,药物浓度为4.5%,制备的纳米粒粒径为（145.4±15.8） nm,Zeta电位值为（-7.6±0.8） mV;透射电镜下可观察到纳米粒表面光滑,分布均匀;葫芦素B-PLGA载药纳米粒释药前期出现突释,后期平缓,48 h药物释放达到86%;葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制作用显著高于葫芦素B。结论 葫芦素B-PLGA载药纳米粒可延缓药物释放,提高对HepG2肝癌细胞的抑制活性,为进一步临床研究奠定实验基础。