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Abstract Polyelectrolyte complexes (PECs) as drug delivery systems are widely explored since they are easily obtained by coacervation and biopolymers can be associated. However, particle distribution is a challenging critical parameter that has been infrequently focused. This work evaluated the effect of NaCl concentration on the physicochemical properties of PECs based on chitosan and hypromellose loaded with methotrexate. The particle size, zeta potential and polydispersity index (PdI) were determined by DLS, besides of drug entrapment efficiency (EE) and in vitro drug release profile determination. Particle size decreased while NaCl concentration rised, achieving a narrower size distribution of (345±79 nm) and PdI (0.285±0.067) with 200 mmol/L NaCl. The higher the NaCl concentration, the lower the zeta potential at acid pH. The EE was kept similar ((28.2±4.5) %) from 0 to 300 mmol/L NaCl, while 400 mmol/L NaCl impaired the drug entrapment. The addition of (200 and 300) mmol/L NaCl did not affect the drug release profile, but it was faster with (100 or 400) mmol/L. In conclusion, the addition of 200 mmol/L NaCl reduced particle size and PdI with no changes in the EE and drug release. Therefore, the ionic strength plays an important role on PECs development.
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Objective: To prepare carboxymethyl Bletilla striata polysaccharide-chitosan@curcumin (CM-BSP) polyelectrolyte complex films, optimize their preparation technology, and evaluate its quality. Methods: CM-BSP was synthesized, then CM-BSP and CS formed water-insoluble complex by electrostatic bonding, the Cur-loaded polyelectrolyte complex films were prepared by a volatilization of solvent method. The formulation and preparation technology were optimized using an orthogonal design method and the morphology and structure were observed by scanning electron microscopy and fourier transform microscopic infrared spectroscopy. Results: The optimal prescription was of CM-BSP 117 mg, CS 233 mg, glycerol 25%, Cur 20 mg. The mean thickness of Cur-loaded polyelectrolyte complex films was (74.0 ± 2.0) μm, drug loading capacities was 95.41%, and in vitro release rate was 93.78%. Conclusion: The obtained polyelectrolyte complex films displayed an smooth exterior inspection, uniform distribution, good drug loading capacities and in vitro release rate.
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This study evaluates various techniques for producing mesalamine (5ASA)-loaded particles employing chitosan as a biopolymer: (1) the polyelectrolyte complexation of chitosan with phthalate hypromelose (HP), (2) the chemical crosslinking of chitosan with genipin and (3) the water-in-oil emulsion method associated with chemical crosslinking with genipin. Systems were characterized by dynamic light scattering, zeta potential (ζ), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and a drug release profile. Method (1) was efficiently produced unloaded nanoparticles (491 nm, PdI=0.26 and ζ = 23.2), but the conditions for chitosan and HP cross-linking enhanced the precipitation of 5ASA. Method (2) caused the degradation of the drug. Method 3 produced sub-micron and microparticles, thereby varying the agitation method; 3 h magnetic agitation resulted in 2692 nm, Pdi = 0.6 and ζ = 46, while Ultra-Turrax, 5 min produced submicron particles (537 nm, PdI = 0.6). The percentage yield was approximately 50%, which is very satisfactory considering the impossibility of encapsulating 5ASA using other methods. FTIR showed the covalent interaction of chitosan and genipin. The drug release was rapid in acidic fluid, but in neutral pH a slower release was obtained in the initial stage, followed by rapid release, which may ensure the controlled release of 5ASA in the colon.
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Capsosomes, a new class of polymer capsules containing liposomes subcompartments, which preserve the advantages of both polyelectrolyte microcapsules and liposomes while eliminating some of the shortcomings, are formed through the layer-by-layer (LBL) assembly of polymers and liposomes and expected to find diverse applications in biomedicine, especially for the creation of artificial cells or organelles. In this review, the design and performance of capsosomes are mainly introduced, and capsosomes are pointed out to be a promising platform toward the creation of therapeutic artificial cells and organelles or as a novel approach for multiple drug delivery.
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Polyelectrolyte layer-by-layer assembled lipid nanoparticles (NPs) were prepared to improve their stability against lipolysis in gastrointestinal tract, and efficiency of oral absorption of doxorubicin (DOX). The lipid NPs were prepared by hot melt-probe sonication method. The polyelectrolyte layer-by-layer assembled lipid NPs (DOX-NPs/CS/γ-PGA) was prepared by layer-by-layer self-assembling polyelectrolytes cationic chitosan (CS) and anionic poly (γ-glutamic acid) (γ-PGA) on the surface of lipid NPs based on electrostatic interaction. The particle size, polydispersity index (PDI) and zeta potential of lipid NPs and DOX-NPs/CS/γ-PGA were determined by dynamic light scattering (DLS). The in vitro drug release was determined in pH 1.2 HCl solution and pH 6.8 phosphate buffer solution (PBS). The stability of lipid NPs against lipolysis was evaluated in simulated gastrointestinal medium containing lipase. The cellular uptake of lipid NPs and DOX-NPs/CS/γ-PGA was evaluated in Caco-2 cell model. The pharmacokinetic of DOX after oral absorption was studied in SD rats. Results showed that the average particle size and zeta potential of DOX-NPs/CS/γ-PGA were 180.6±5.4 nm and -38.53±0.29 mV, respectively. The DOX-NPs/CS/γ-PGA effectively slowed down the release of DOX from nanoparticles, and decreased the lipolysis of lipid NPs in simulated gastrointestinal medium. The cell study showed that DOX-loaded lipid NPs and DOX-NPs/CS/γ-PGA remarkably enhanced the cell uptake in comparison with DOX solution. The DOX-NPs/CS/γ-PGA significantly improved oral absorption of DOX compared with DOX-loaded lipid NPs. The Cmax, tmax were 0.76±0.25 μg·mL-1 and 0.5 h, respectively; AUC0-24h was 3.02 folds and the relative bioavailability was 302.46% with DOX solution as reference. The stability of lipid NPs against lipolysis and drug release were significantly improved by layer-by-layer assembling, leading to an improved oral absorption.
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We investigated the polyelectrolyte properties of actin filaments which are in interaction with myosin motors, basic participants in mechano-electrical transduction in the stereocilia of the inner ear. Here, we elaborated a model in which actin filaments play the role of guides or pathways for localized flow of calcium ions. It is well recognized that calcium ions are implicated in tuning of actin-myosin cross-bridge interaction, which controls the mechanical property of hair bundle. Actin filaments enable much more efficient delivery of calcium ions and faster mechanism for their distribution within the stereocilia. With this model we were able to semiquantitatively explain experimental evidences regarding the way of how calcium ions tune the mechanosensitivity of hair cells.
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A adição de polieletrólito ao processo de floculação no tratamento físico-químico por coagulação-floculação-sedimentação de efluentes tem sido uma alternativa para a obtenção de clarificados de boa qualidade em menor tempo devido ao aumento da velocidade de sedimentação. Deste modo, este artigo, objetivou determinar as inter-relações entre as variáveis pH, gradiente de floculação, dosagem de ferro e tipo de polieletrólito e avaliar o efeito desta adição na remoção de cor, DQO e turbidez no pós-tratamento do lixiviado submetido a tratamento biolõgico. Através do uso da técnica de planejamento e analisando-se os resultados obtidos, pôde-se verificar que o polímero de carga catiônica apresentou-se como o mais eficiente, obtendo remoções de até 97,70% para cor verdadeira, 81,52% para DQO e 92,18% para turbidez.
The addition of polyelectrolyte flocculation process in the physical-chemical treatment by coagulation-flocculation-sedimentation effluent has been an alternative to obtain clarification of good quality in less time due to increased sedimentation rate. Thus, this article aimed to determine the interrelationships between the pH gradient, flocculation, iron dosage and type of polyelectrolyte and evaluate the effect of this addition on color removal, COD and turbidity in the post-treatment of the leachate subjected to pretreatment biological. Through the use of technical planning and analyzing the results, it was found that the polymer cationic charge introduced himself as the most efficient, achieving removals of up to 97.70% for true color, 81.52% for COD and 92.18% for turbidity.
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OBJECTIVE: To fabricate a novel sandwich-type drug carrier called "capsosome" using natural polyelectrolytes such as chitosan and alginate, then characterize the structure, drug loading and release profile. METHODS: Chitosan and alginate and DMPG (Dimyristoyl Phosphatidylglycerole) liposomes were coated on the CaCO3 microparticles using layer-by-layer assembly technique. Upon removal of the CaCO3 template core, stable capsosomes, containing one layer of intact liposomes as cargo, were obtained; As a model drug, DOX with different concentrations was used to evaluate the drug loading ability of capsosome, the cumulative release a-mount was determined at different time points. RESULTS: Confocal laser scanning microscope images and transmission electron microscope images indicated that liposomes were embeded in the microcapsule shell successfully, drug loading amount of the obtained capsosomes increased with the DOX incubation concentration increasing (100-1000 μg · mL-1), the highest loading amount could reach to 30.47 × 10-3 ng/each capsosome, the cumulative release amount was about 46% in 48 h. CONCLUSION: The capsosome had favourable drug loading and release ability, it deserved to be studied as a novel drug carrier. Copyright 2012 by the Chinese Pharmaceutical Association.
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Objective To Investigate the in vitro and in vivo release of chitosan-alginate microgels coated layer-by-layer by polyelectrolyte self-assembly. Methods The cores of the microgels were made by gelatinization using electrostatic microencapsulated and coated by polyelectrolytes using electrostatic attraction. The effects of different layers and ratios of polymer on the in vitro lease of FITC-dextran were evaluated. Histrological examination was carried out to observe the in vivo release process by injecting the coated microgels into mice. Results The results showed that alginate and calcium chloride concentrations and polyelectrolyte layers markedly affected the lag time of pulsed release and the relasing speed after lagging. Conclusion The release of microgels coated layer-by-layer by polyllectrolyte can be controlled in vitro and can be observed in vivo; meanwhile, the microgels are safe and have good biocompatibility.
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Objective To Investigate the preparation method, the release profile and structure of the polyelectrolyte layer- by-layer coated chitosan-alginate microgels. Methods The cores of the microgels were prepared by a high voltage electrostatic system, and the semipermeable membrane outside the microgel was polyelectrolyte deposits on the core surface through electrostatic attraction. The influences of different ratios of materials on the expansion property and the in vitro cumulative release of the coated microgels were evaluated by a single factor experiment. Results The prepared polyelectrolyte-coated microgels were well-shaped, with a narrow range of diameter distribution. The lag time of in vitro release was 2. 67 h; the release was rapid after lagging, with the cumulative in vitro release being 72% within 3 h. Conclusion Polyelectrolyte layer-by- layer coated chitosan-alginate microgels can release payload in a pulsed fashion in vitro.
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Objective:To investigate whether chitosan-polyelectrolyte complex (CS-PEC) can be used as scaffold for chondrocyte culture and for cartilage regeneration in vivo.Methods:Condylar chondrocytes of fetal mouse were seeded onto the three-dimension gel scaffolds of CS-PEC and cultured.The cultured chondrocytes/CS-PEC complex samples were transplanted subcutaneously into nude mice and the CS-PEC scaffold without chondrocyte was used as the control.The animals were sacrificed 4 and 8 weeks after operation respectively.Cartilage formulation was observed by histological and immunohistochemical methods.Results:In the in vitro culture the majority of cells attached to the CS-PEC surface and expanded rapidly. 4 weeks after transplantation,in the chondrocytes/CS-PEC complex the scaffold maintained mostly the original structure. Hypertrophic chondrocytes appeared in scaffold materials. CollagenⅡwas positive in the new cartilage. 8 weeks after transplantation the scaffold degraded almost completely and new cartilage could be observed. CollagenⅡ and cartilage matrix was positive in the new cartilage and the collagen I was positive in the surrounding fibroblast-like cells. In control transplants,8 week after transplantation some fibre-like tissue formed in the circumference, but there was no new cartilage formation and the collagen II and the cartilage matrix was negative.Conclusions:CS-PEC may be used as scaffold for fibre-cartilage regeneration.
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VE: Chitosan and sodium tripolyphosphate were used as Complex matrix material for preparing pellets loading sodium diclofenac and its properties were studied. METHODS Chitosantripolyphosphate sodium polyelectrolyte was prepared according to the principle of static electricity polymerization. Its properties and structure characteristics were further investigated. The preparation process, effective factors and the optimal condition for the pellets loading sodium diclofenac were studied. RESULTS IR indicated that the structure of compound contained -NH3+-O-P group. DTA demonstrated that polyelectrolyte had an exothermic peak. There was no interaction between the drug and expedient. SEM showed that the surface of the pellets was regular, dense and the structure of the surface wasn't consistent with the inner. The pellets prepared by this method were uniform, round, well-distributed, hardy, good-mobility and its average diameter was about 10mm. CONCLUSION Chitosan-tripolyphosphate sodium polyelectrolyte could be used as a good matrix material for preparing pellets.
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Solutions of chitosan and carrageenan were co-reacted under various experimental conditions to form water-insoluble precipitates. DR. spectroscopic studies and the counter -ions analyses revealed that the combination of the polyions proceeded through the electrostatic interaction between the - NH+3 of chitosan and the - SO3 of carrageenan, and the mole retios of N/S in the poly-electrolyte complexes (PEC) thus prepared have large scope depending on pH, the degree of deacetyla-tion (DD) of chitosan as well as the mixin ratio of the complexing components. The observation of the PEC by scanning electron microscopy showed that there exist fibrous structures in some PEC depending on such reactive conditions as pH, DD of chitosan related with the charge densities of chitosan chains. The solubility of PEC, which is greatly affected by the DD of chitosans, and the blood compatibility have also been studied.