首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The objective of this work is to produce doxorubicin-loaded galactose-conjugated poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to be specifically recognised by human hepatoma cellular carcinoma (Hep G2) cells and assess NPs cytotoxicity. Doxorubicin-unloaded and doxorubicin-loaded galactose-conjugated PLGA NPs were prepared using an emulsion method and characterised for morphology, size, drug release behaviour, Hep G2 recognition and cell cytotoxicity. The produced doxorubicin-loaded PLGA-galactose-conjugate nanoparticles (PLGA-GAL NPs) are spherical in shape with a size of 365?±?74?nm, a drug encapsulation efficiency of 69% and released in a biphasic pattern with higher release rates at pH 5. In vitro cell studies confirmed the specific interaction between the receptors of Hep G2 and the PLGA-GAL NPs. Cell cytotoxicity tests showed that unloaded NPs are non-toxic and that doxorubicin-loaded NPs caused a cellular viability decrease of around 80%, therefore representing a promising approach to improve liver-specific drug delivery.  相似文献   

2.
The present investigation was aimed at developing PEGylated PLGA nanoparticles of cytarabine. PLGA Nanoparticles were prepared by modified nanoprecipitation method, optimized for mean particle size (152?±?6?nm) and entrapment efficiency (41.1?±?0.8%) by a 32 factorial design. The PEGylated PLGA nanoparticles of cytarabine had a zeta potential of ?7.5?±?1.3?mV and sustained the release of cytarabine for 48?h by Fickian diffusion. The IC50 values for L1210 cells were 6.5, 5.3, and 2.2?µM for cytarabine, cytarabine loaded PLGA nanoparticles and cytarabine loaded PLGA-mPEG nanoparticles respectively. Confocal microscopy and flow cytometry showed that the nanoparticles were internalized by the L1210 cells and not simply bound to their surface. Biodistribution studies showed that the PEGylated nanoparticles of cytarabine were present in significantly higher concentrations in blood circulation as well as in brain and bones and avoided RES uptake as compared to the free drug.  相似文献   

3.
Abstract

A current treatment strategy for peritoneal ovarian cancer is a combination of peritoneal surgery and multi-drug-based chemotherapy that often involves intraperitoneal (IP) injection. A thermosensitive poly-(d,l-lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly-(d,l-lactide-co-glycolide) (PLGA-b-PEG-b-PLGA) hydrogel platform (thermogels) enabled gel loading of poorly work-soluble paclitaxel (cytotoxic agent), 17-allylamino-17-demethoxygeldanamycin (17-AAG, heat shock protein inhibitor), and rapamycin (mammalian target of rapamycin protein inhibitor). PLGA-b-PEG-b-PLGA thermogels (15%) carrying paclitaxel, 17-AAG, and rapamycin (named Triogel) made a successful transition from a free-flowing solution below ambient temperature to a gel depot at body temperature. Triogel gradually released paclitaxel, 17-AAG, and rapamycin at an equal release rate in response to the physical gel erosion. In an ES-2-luc ovarian cancer xenograft model, a single IP injection of Triogel (60, 60, and 30?mg/kg of paclitaxel, 17-AAG, and rapamycin, respectively) significantly reduced tumor burden and prolonged survival of ES-2-luc-bearing nude mice without notable systemic toxicity relative to those delivered by poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles in solution via IP or intravenous (IV) injection route. These results show a great potential of a biodegradable thermogel platform carrying multi-drugs for IP chemotherapy in peritoneal ovarian cancer.  相似文献   

4.
The present study was intended to develop poly(d,l-lactide-co-glycolide) (PLGA; 50:50, 0.15 dL/g) microspheres (MS) loaded with yuanhuacine (YHC) for passive targeting in lung as well as providing a simple evaluation method for the targeting efficiency of MS. A kind of photochromic spiropyran dye was applied to label MS to clearly demonstrate the in vivo distribution characteristics through intravenous injection into mice and rabbits. Sections of 10-μm thickness from different organs were cut using a microtome, and fluorescent microscopy was used to determine the biodistribution of the MS. The average particle size of MS was 9.0 μm, and the glass transition temperature was 37–40°C. In vitro, the cumulative release achieved 50.8% in 24 h. Histological sections from different organs indicated that the amount of MS in lung achieved maximum in 6 h, as about 8 times as in liver and 70 times higher than the average concentration of other organs. In vivo, MS were gradually swelled and drug concentration remained just 10% in 12 h, which would not result in long time embolization in the lung. This evaluation method supplies a simple and visualized channel in focus for the targeting efficiency of PLGA MS.  相似文献   

5.
Polymeric micelles have been widely explored preclinically as suitable delivery systems for poorly soluble chemotherapeutic drugs in cancer therapy. The present study reported the development of cholesterol (Ch)-conjugated poly(D,L-Lactide) (PLA)-based polymeric micelles (mPEG–PLA-Ch) for effective encapsulation and delivery of curcumin (CUR) at the tumor site. Cholesterol conjugation dramatically affected the particle size and improved drug loading (DL) and encapsulation efficiency (EE). mPEG–PLA-Ch-CUR showed bigger hydrodynamic diameter (104.6?±?2.1?nm, and 169.3?±?1.52?nm for mPEG–PLA and mPEG–PLA-Ch, respectively) due to increased size of the hydrophobic core. The newly developed polymer exhibited low critical micelles concentration (CMC) (25?μg/mL) which is close to lipid-based polymer, PEG-phosphatidyl ethanolamine (12.5?μg/mL) compared to mPEG–PLA (50?μg/mL). mPEG–PLA-Ch micelles exhibited relatively higher EE (93.74?±?1.6%) and DL (11.86?±?0.8%) compared to mPEG–PLA micelles (EE 91.89?±?1.2% and DL 11.06?±?0.8%). mPEG–PLA-Ch micelles were internalized by the cancer cells effectively and exhibited higher cytotoxicity compared to free CUR in both, murine melanoma (B16F10) and human breast cancer (MDA-MB-231) cells. mPEG–PLA-Ch exhibited satisfactory hemocompatibility indicating their potential for systemic application. Further, mPEG–PLA-Ch-CUR demonstrated higher rate of reduction of tumor volume in B16F10-xenografted tumor-bearing mice compared to free CUR. At the end of 22 days, the tumor reduced to 1.87-fold (627.72?±?0.9?mm3 versus 1174.68?±?1.64?mm3) compared to the treatment with free CUR. In conclusion, the experimental data in vitro and in vivo indicated that the newly developed CUR-mPEG–PLA-Ch micelles may have promising applications in solid tumors.  相似文献   

6.
Characterization of biodegradable polymers used for controlled drug delivery is essential to ensure reproducibility of in vitro and in vivo performance. Selected characterization techniques established for poly(d,l-lactide-co-glycolide) (PLGA) copolymers included DSC to analyse thermal behavior, 13C-NMR to determine exact comonomer ratios and comonomer sequencing, cloud point titration to establish solubility, SEC to monitor molecular weight averages and polydispersity, SEM to observe surface morphology, BET gas adsorption to analyse surface area, tapped bulk density measurements to suggest internal pore structure and porosity and finally in vitro degradation to analyse degradation times and profiles. Comonomer ratios of 50:50 PLGAs were found to be closer to stated values for Boehringer Ingelheim polymers than for polymers from two other suppliers. Implementing such a characterization program for biodegradable polymers ensures the production of reproducible and reliable controlled drug delivery systems.  相似文献   

7.
The effect of gamma-irradiation on the physicochemical properties of peptide-containing hydrophilic poly (d,l-lactide-co-glycolide) (PLGA) microspheres was evaluated. PLGA (50/50, Mw: 8,600) with free carboxylic end groups was used to make drug-loaded and placebo microspheres by a solvent extraction evaporation method. Both formulated and non-formulated microspheres were gamma-irradiated at 0, 1, 1.5, and 2.5 Mrad doses. HPLC analysis based on extraction of peptide from the microspheres showed that peptide content of the microspheres was lowered upon irradiation and the reduction was more pronounced in formulated microspheres. The in-vitro release in 0.033M phosphate buffer, pH 7.0 at 37 degrees C (based on extraction of residual peptide) showed that the initial and subsequent release of peptide was higher in gamma-irradiated microspheres during the first 20 days. The difference became insignificant during the erosional controlled release of the peptide. There was no difference in release between the formulated and non-formulated microspheres of the nonirradiated or irradiated forms. Molecular weights (Mw and Mn), determined by size exclusion chromatography, were reduced by gamma-irradiation for both formulated and non-formulated placebo microspheres. Differential scanning calorimetry showed a gradual reduction in Tg of placebo microspheres but no reduction in peptide-loaded microspheres. In-vivo evaluation of the nonirradiated and the 1.5 Mrad irradiated microspheres showed no marked differences through 28 days. Since irradiation caused a lowering of Mw and Mn with the appearance of a low amount of unidentified substances, seemingly catalyzed by the polymer and the formulation excipients, gamma-irradiation sterilization of these parenteral delivery systems requires careful investigation on an individual product basis.  相似文献   

8.
Abstract

Candesartan cilexetil (CC) is used in the treatment of hypertension and heart failure. It has poor aqueous solubility and low oral bioavailability. In this work, CC loaded solid lipid nanoparticles (CC-SLNs) were developed to improve the oral bioavailability. Components of the SLNs include either of trimyristin/tripalmitin/tristearin, and surfactants (Poloxamer 188 and egg lecithin E80). The CC loaded nanoparticles were prepared by hot homogenization followed by ultrasonication method. The physicochemical properties, morphology of CC-SLNs were characterized, the pharmacokinetic and pharmacodynamic behaviour of CC-SLNs were evaluated in rats. Stable CC-SLNs having a mean particle size of 180–220?nm with entrapment efficiency varying in between 91–96% were developed. The physical stability of optimized formulation was studied at refrigerated and room temperature for 3 months. Further, freeze drying was tried for improving the physical stability. DSC and XRD analyses indicated that the drug incorporated into SLN was in amorphous form but not in crystalline state. The SLN-morphology was found to be nearly spherical by electron microscopic studies. Pharmacokinetic results indicated that the oral bioavailability of CC was improved over 2.75-fold after incorporation into SLNs. Pharmacodynamic study of SLNs in hypertensive rats showed a decrease in systolic blood pressure for 48?h, while suspension showed a decrease in systolic blood pressure for only 2?h. Taken together, these effects are due to enhanced bioavailability coupled with sustained action of CC in SLN formulation. Thus, the results conclusively demonstrated the role of CC-SLNs for a significant enhancement in oral bioavailability along with improved pharmacodynamic effect.  相似文献   

9.
The objective of this work was to develop a fast and significant method for the determination of the intraparticulate pore size distribution of microspheres. Poly(lactide-co-glycolide) (PLGA) microspheres prepared with a solvent extraction/evaporation process were studied. From the envelope and the skeletal volume of the microspheres the porosity was calculated. The skeletal volume was determined with nitrogen and helium pycnometry and mercury intrusion porosimetry. Based on single particle optical sensing (SPOS) a novel method was developed by which the envelope volume is calculated from the particle size distribution (PSD), provided that all particles have a spherical shape. The penetration capacity of the applied intrusion media is limited by their atomic or molecular diameter or by the surface tension and the pressure in case of mercury. A classification of the pore structure was obtained by comparing these different skeletal values with the values for the envelope volume. Two well separated pore fractions were found, a nanoporous fraction smaller than 0.36nm and a macroporous fraction larger than 3.9μm. The total porosity and the ratio between both fractions is controlled by the preparation process and was shown to depend on the solvent extraction temperature.  相似文献   

10.
Synthetic short interfering RNA (siRNA) is promising for specific and efficient knockdown of disease-related genes. However, in vivo application of siRNA requires an effective delivery system. Commonly used siRNA carriers are based on polycations, which form electrostatic complexes with siRNA. Such poly- or lipoplexes are of limited use in vivo due to severe problems associated with toxicity, serum instability and non-specific immune-responses. The aim of the present study was to prepare uniformly sized nanoparticles (NPs) with a high load of siRNA by use of the safe and biodegradable poly-(dl-lactide-co-glycolide) (PLGA) polymer without including polycations. The siRNA was encapsulated in the core of NPs by the double emulsion solvent evaporation method. To optimize the NP formulation, the effects of important formulation and processing parameters were investigated systematically. Generally, spherical siRNA-loaded NPs (<300 nm, PDI < 0.2, zeta potential −40 mV) were obtained. An encapsulation efficiency of up to 57% was achieved by adjusting the inner water phase volume, the PLGA concentration, the first emulsification sonication time, and stabilization of the water–oil interface with serum albumin. The integrity of siRNA was preserved during the preparation. Preparation of core-loaded siRNA-NPs based on PLGA and no cationic excipient seems possible and promising for delivery of siRNA.  相似文献   

11.
Flavone acetic acid (FAA) is a new antitumor agent that has recently entered Phase I clinical trials. In preclinical studies, we have found that FAA was broadly active against a variety of transplantable solid tumors of mice (colon #51, #07, #10, #26; pancreatic ductal adenocarcinomas #02 and #03; mammary adenocarcinoma #16/C/Adr; M5076 reticulum cell sarcoma and Glasgow's osteosarcoma). FAA was curative for colon adenocarcinoma # 10 and pancreatic ductal adenocarcinoma # 03. Thus, for the first time an agent has been identified with very broad, perhaps nearly universal solid tumor activity. FAA was also found to be orally active and stable in solution at 37 °C for 48 h. FAA was selectively cytotoxic in vitro for solid tumors over leukemias L1210 and P388 (in a soft-agar colony formation assay), thus correlating cellular selectivity in vitro with in vivo antitumor activity. The finding that FAA was active in vitro, established that the agent did not need metabolism (activation) outside the tumor cell. The main drawback of FAA was an unusual threshold behavior in which only a narrow range of doses were active and splitting the dose markedly decreased activity.  相似文献   

12.
13.
Heuristic modeling of drug delivery to malignant brain tumors   总被引:2,自引:0,他引:2  
It is apparent that chemotherapy against malignant brain tumors is generally ineffective. While some agents are more effective than others, none appreciably alters the clinical course of and the poor prognosis for patients with brain tumors. Even though new and more effective agents are being or will be developed, chemotherapy depends as much on the delivery of drug as it does on the drug used. Therefore, we have defined factors that we believe are of primary importance in drug delivery to brain tumors, and, using computer simulation, we have modeled the effects of these factors. In this article we discuss (a) the extent of the breakdown in the blood-brain barrier (BBB) that accompanies the development of malignant tumors in the brain, (b) factors that influence drug transport from tumor capillaries to tumor cells at varying distances from the capillaries, (c) the problems inherent in drug delivery from a well-vascularized tumor outward to normal brain tissue that might harbor malignant cells but that does not have leaky vessels (i.e., normal BBB), and (d) the difficulties in drug delivery from a well-perfused, highly permeable outer tumor shell to a central, poorly perfused tumor core.This work was supported by American Cancer Society Grant CH-75 and NIH Program Project Grant CA-13525. V. A. L. is the recipient of an American Cancer Society Faculty Research Award (FRA-155).  相似文献   

14.
This work describes a method for preparation of sub-micron poly(d,l-lactide-co-glycolide) (PLGA) particles loaded with magnetite/maghemite nanoparticles to be used as magnetically-controlled drug delivery systems. The methodology of simple emulsion/evaporation technique has been optimized to provide greater iron oxide loading rates. The surface of iron oxide nanoparticles was coated with oleic acid (OA) for better compatibility with organic phase containing the polymer. To increase their loading into polymeric sub-micron particles, we added dried iron oxide nanoparticles in variable ferrite/polymer ratio of 1:1; 1:1.5 and 1:2 w/w. Composition and surface properties of obtained composite sub-micron particles have been studied in comparison with those of ferrite-free PLGA sub-micron particles. Presence of magnetite/maghemite was qualitatively confirmed by characteristic bands in the FT-IR spectra of composite sub-micron particles. Quantification of the incorporated iron was achieved by AAS. The highest incorporation rates of ferrite (up to 13.5% w/w) were observed with initial ferrite/polymer ratio of 1:1 w/w. TEM images indicate that the composite sub-micron particles are nearly spherical. According to laser granulometry data, average hydrodynamic diameter of the composite sub-micron particles is close to 280nm, independently of ferrite presence. Electrophoretic properties (zeta potential) were very similar for both composite and ferrite-free PLGA sub-micron particles, thus indicating that the polymeric coating should mask the surface of ferrite nanoparticles buried inside. Finally, composite sub-micron particles exhibit superparamagnetic property.  相似文献   

15.
Intratympanic (IT) therapies have been explored to address several side effects that could be caused by systemic administration of steroids to treat inner ear diseases. For effective drug delivery to the inner ear, an IT delivery system was developed using poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and thermosensitive gels to maintain sustained release. Dexamethasone (DEX) was used as a model drug. The size and zeta potential of PLGA NPs and the gelation time of the thermosensitive gel were measured. In vitro drug release was studied using a Franz diffusion cell. Cytotoxicity of the formulations was investigated using SK-MEL-31 cells. Inflammatory responses were evaluated by histological observation of spiral ganglion cells and stria vascularis in the mouse cochlea 24 h after IT administration. In addition, the biodistribution of the formulations in mouse ears was observed by fluorescence imaging using coumarin-6. DEX-NPs showed a particle size of 150.0 ± 3.2 nm in diameter and a zeta potential of −18.7 ± 0.6. The DEX-NP-gel showed a gelation time of approximately 64 s at 37 °C and presented a similar release profile and cytotoxicity as that for DEX-NP. Furthermore, no significant inflammatory response was observed after IT administration. Fluorescence imaging results suggested that DEX-NP-gel sustained release compared to the other formulations. In conclusion, the PLGA NP-loaded thermosensitive gel may be a potential drug delivery system for the inner ear.  相似文献   

16.
目的: 研制负载利福喷丁的聚乳酸-羟基乙酸共聚物[poly(lactic-co-glycolic acid),PLGA]纳米粒,并对其处方及制备工艺进行优化。方法: 采用快速膜乳化法制备利福喷丁/PLGA纳米粒。通过单因素实验考察了乳化剂浓度、PLGA浓度、油相/水相体积比、初乳制备转速、初乳制备时间、过膜压力、过膜次数对纳米粒制备的影响。在此基础上以粒径、载药率、包封率为评价指标,使用正交实验设计对纳米粒制备的处方工艺进行优化,以TOPSIS法进行多指标综合分析。然后对最优处方工艺进行验证,并对载药纳米粒的体外释药行为进行考察。结果: 经最优处方工艺制备的载药纳米粒,粒径(428±11.4)nm,粒径分布为(0.186±0.036),包封率为(76.89±2.6)%,载药率为(10.89±1.2)%。用透视电镜观察呈均匀分布的球形。在体外药物释放实验中,药物在72 h内累计释放了78.81%。结论: 采用快速膜乳化可以简单快捷地制备均匀圆整、包封性好、具有良好缓释性能的利福喷丁/PLGA纳米粒,并为新型抗结核精准治疗的开发提供了基础。  相似文献   

17.
Abstract

Objective: The aim of this study was to develop nanostructured lipid carriers (NLCs) as well as solid lipid nanoparticles (SLNs) and evaluate their potential in the topical delivery of meloxicam (MLX).

Materials and methods: The effect of various compositional variations on their physicochemical properties was investigated. Furthermore, MLX-loaded lipid nanoparticles-based hydrogels were formulated and the gels were evaluated as vehicles for topical application.

Results and discussion: The results showed that NLC and SLN dispersions had spherical shapes with an average size between 215 and 430?nm. High entrapment efficiency was obtained ranging from 61.94 to 90.38% with negatively charged zeta potential in the range of ?19.1 to ?25.7?mV. The release profiles of all formulations exhibited sustained release characteristics over 48?h and the release rates increased as the amount of liquid lipid in lipid core increased. Finally, Precirol NLC with 50% Miglyol® 812 and its corresponding SLN were incorporated in hydrogels. The gels showed adequate pH, non-Newtonian flow with shear-thinning behavior and controlled release profiles. The biological evaluation revealed that MLX-loaded NLC gel showed more pronounced effect compared to MLX-loaded SLN gel.

Conclusion: It can be concluded that lipid nanoparticles represent promising particulate carriers for topical application.  相似文献   

18.
《Drug delivery》2013,20(7):493-501
The efficacy of antisense oligodeoxynucleotides (AsODNs) is compromised by their poor stability in biological fluids and the inefficient cellular uptake due to their size and negative charge. Since chemical modifications of these molecules have resulted in a number of non-antisense activities, incorporation into particulate delivery systems has offered a promising alternative. The aim of this study was to evaluate various poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles for AsODN entrapment and delivery. PLGA nanoparticles were prepared using the double emulsion solvent evaporation method. The influence of formulation parameters such as PLGA concentration and volume ratio of internal aqueous phase volume (Va1) to organic phase volume (Vo) to external aqueous phase volume (Va2) on particle size, polydispersity index (PDI) and zeta potential (ZP) was investigated using a full factorial study. The particle size increased with increasing PLGA concentrations and volume ratios, with an interaction detectable between the two factors. AsODN entrapment efficiencies ranged between 49.97% and 54.95% with no significant difference between various formulations. By fitting the in vitro release profiles to a dual first order release model it was shown that the AsODN release occurred via two processes: a diffusion controlled process in the early phase (25 to 32% within one day) and a PLGA degradation process in the latter (39 to 70% after 14 days). Cellular uptake studies using primary corneal epithelial cells suggested active transport of nanoparticles via endocytosis. PLGA nanoparticles therefore show potential to successfully entrap AsODNs, transport them into cells and release them over time due to polymer erosion.  相似文献   

19.
The objective of this study was to evaluate formulation variables such as drug load and addition of a porosigen in achieving an increased initial release of peptide from poly(d,l-lactide-co-glycolide) (PLGA) microspheres by altering carrier characteristics. Leuprolide acetate-loaded PLGA microspheres were prepared by a solvent-extraction–evaporation process and were characterized for their drug load (HPLC assay), bulk density (tapping method), size distribution (dynamic light scattering), specific surface area (Brunauer–Emmett–Teller [BET] analysis), surface morphology (scanning electron microscopy), in vitro drug release (at 37°C), and in vivo efficacy (suppression of rat serum testosterone). Increasing the drug load, and adding various amounts of calcium chloride to organic and aqueous phases of the emulsion during processing yielded particles with increased porosity, lower bulk density, higher specific surface area, and accordingly higher initial release. In an animal model, these formulations showed a faster onset of testosterone suppression compared to microspheres without higher drug load or calcium chloride. The approaches employed in this study were found to be effective in avoiding the therapeutic lag phase usually observed with microencapsulated macromolecular drugs.  相似文献   

20.
Purpose The purpose of this study was to evaluate the ability of poly(ethylene glycol)-coated lipid nanocapsules (LN) to deliver the highly potent hydrophobic anticancer drug docetaxel to solid tumors. Methods Docetaxel-loaded nanocapsules (80–120 nm) were produced by a solvent-free phase inversion process and were coated with polyethylene glycol distearoylphosphatidylethanolamine conjugate by a postinsertion step. In vivo studies were conducted in mice bearing subcutaneously implanted C26 colon adenocarcinoma to assess the pharmacokinetics and biodistribution of both the drug and LN. Results Incorporation of docetaxel into the LN dramatically increased the drug's biological half-life while providing substantial accumulation at the tumoral site. The pharmacokinetics and biodistribution pattern were found to depend on the specific surface area and shell composition of the nanocapsules. Conclusion This study demonstrates that docetaxel physically entrapped into a lipid colloidal drug carrier can be efficiently targeted to neoplastic tissues.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号