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Kimiko Makino - One of the best experts on this subject based on the ideXlab platform.
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Factors affecting the loading efficiency of water-soluble drugs in PLGA microspheres.
Colloids and surfaces. B Biointerfaces, 2007Co-Authors: Fuminori Ito, Hiroyuki Fujimori, Kimiko MakinoAbstract:Poly(lactide-co-glycolide), PLGA, microspheres containing Blue Dextran as a hydrophilic model drug were prepared by a solvent evaporation method from w/o/w emulsions using a micro homogenizer. Effects of surfactant concentration in oil phase, stirring time period and stirring rate in the preparation procedure of primary emulsion (w/o) upon drug-loading efficiency were evaluated. Stirring rate during preparation of primary emulsion and surfactant concentration in oil phase affected drug-loading efficiency and the particle size of primary emulsion. Microspheres having the higher drug-loading efficiency were obtained when size differences between the primary emulsions and the secondary ones were large. That is, when the diameter of the primary emulsion is much smaller than that of the secondary emulsion, PLGA microspheres with high-loading efficiency of Blue Dextran were obtained.
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Incorporation of water-soluble drugs in PLGA microspheres.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: Fuminori Ito, Hiroyuki Fujimori, Kimiko MakinoAbstract:Abstract Poly(lactide- co -glycolide) (PLGA) microspheres containing Blue Dextran, as a model of water-soluble drugs, were prepared from w 1 /o/w 2 emulsions by using a microhomogenizer and a solvent evaporation method. Effects of preparation conditions, such as, concentration of poly(vinyl alcohol) (PVA) in w 2 phase, viscosity of inner soluble water phase, volume ratio of oil phase to w 1 phase in primary emulsion, PLGA concentration in oil phase, and molecular weight or composition of PLGA, upon the properties of PLGA microspheres containing water-soluble drugs were examined. Concentration of poly(vinyl alcohol) (PVA), the dispersant dissolved in w 2 phase of secondary emulsion did not show any effects on the final particle size. On the other hand, volume ratio of oil phase to water one in primary emulsion affected the final particle size, which seemed to be related to the local PLGA concentration in w 1 /o emulsions. That is, the particle size increased as the volume ratio of w 1 phase against oil phase, w 1 /o (v/v), increased. The loading efficiency, however, was not affected by the volume ratio of w 1 /o (v/v), but affected by Blue Dextran concentration in w 1 phase. Higher loading efficiency was observed in PLGA microspheres prepared from w 1 phase containing lower concentration of Blue Dextran. Blue Dextran solution (inner water phase) with the lower viscosity may result in the lower leakage ratio of Blue Dextran during the preparation procedure. Increases in concentration and molecular weight of PLGA made particle size larger.
Jean-marc Porcher - One of the best experts on this subject based on the ideXlab platform.
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Use of transepithelial electrical resistance in the study of pentachlorophenol toxicicity
Toxicology in Vitro, 1999Co-Authors: G. Velarde, Selim Ait-aissa, Chantal Gillet, Françoise Rogerieux, Claude Lambre, Eric Vindimian, Jean-marc PorcherAbstract:The toxicity of pentachlorophenol (PCP), a polluting substance believed to exert a narcotic effect, was assayed using the Caco-2 cell line as a model. In order to assess this toxicity as fully as possible, several viability tests, each examining different endpoints, have been used. Neutral red uptake was found to be more sensitive to PCP than MTT and Alamar Blue tests. Transepithelial electrical resistance (TEER) was shown to be the most sensitive to PCP at concentrations and exposure times where the Alamar Blue, LDH leakage and Blue Dextran passage did not evidence any effect. Blue Dextran passage and optical microscopy revealed cellular detachment at concentrations where LDH and Alamar Blue showed little or no cytotoxicity. Thus, PCP seems to affect the integrity of the intestinal barrier at levels where no cytotoxicity is seen. Our results support the notion that TEER can be used as a very sensitive method for evaluating membrane-perturbing toxicants.
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Use of transepithelial electrical resistance in the study of pentachlorophenol toxicity.
Toxicology in vitro : an international journal published in association with BIBRA, 1999Co-Authors: G. Velarde, Selim Ait-aissa, Chantal Gillet, Françoise Rogerieux, Claude Lambre, Eric Vindimian, Jean-marc PorcherAbstract:The toxicity of pentachlorophenol (PCP), a polluting substance believed to exert a narcotic effect, was assayed using the Caco-2 cell line as a model. In order to assess this toxicity as fully as possible, several viability tests, each examining different endpoints, have been used. Neutral red uptake was found to be more sensitive to PCP than MTT and Alamar Blue tests. Transepithelial electrical resistance (TEER) was shown to be the most sensitive to PCP at concentrations and exposure times where the Alamar Blue, LDH leakage and Blue Dextran passage did not evidence any effect. Blue Dextran passage and optical microscopy revealed cellular detachment at concentrations where LDH and Alamar Blue showed little or no cytotoxicity. Thus, PCP seems to affect the integrity of the intestinal barrier at levels where no cytotoxicity is seen. Our results support the notion that TEER can be used as a very sensitive method for evaluating membrane-perturbing toxicants.
Fuminori Ito - One of the best experts on this subject based on the ideXlab platform.
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Factors affecting the loading efficiency of water-soluble drugs in PLGA microspheres.
Colloids and surfaces. B Biointerfaces, 2007Co-Authors: Fuminori Ito, Hiroyuki Fujimori, Kimiko MakinoAbstract:Poly(lactide-co-glycolide), PLGA, microspheres containing Blue Dextran as a hydrophilic model drug were prepared by a solvent evaporation method from w/o/w emulsions using a micro homogenizer. Effects of surfactant concentration in oil phase, stirring time period and stirring rate in the preparation procedure of primary emulsion (w/o) upon drug-loading efficiency were evaluated. Stirring rate during preparation of primary emulsion and surfactant concentration in oil phase affected drug-loading efficiency and the particle size of primary emulsion. Microspheres having the higher drug-loading efficiency were obtained when size differences between the primary emulsions and the secondary ones were large. That is, when the diameter of the primary emulsion is much smaller than that of the secondary emulsion, PLGA microspheres with high-loading efficiency of Blue Dextran were obtained.
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Incorporation of water-soluble drugs in PLGA microspheres.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: Fuminori Ito, Hiroyuki Fujimori, Kimiko MakinoAbstract:Abstract Poly(lactide- co -glycolide) (PLGA) microspheres containing Blue Dextran, as a model of water-soluble drugs, were prepared from w 1 /o/w 2 emulsions by using a microhomogenizer and a solvent evaporation method. Effects of preparation conditions, such as, concentration of poly(vinyl alcohol) (PVA) in w 2 phase, viscosity of inner soluble water phase, volume ratio of oil phase to w 1 phase in primary emulsion, PLGA concentration in oil phase, and molecular weight or composition of PLGA, upon the properties of PLGA microspheres containing water-soluble drugs were examined. Concentration of poly(vinyl alcohol) (PVA), the dispersant dissolved in w 2 phase of secondary emulsion did not show any effects on the final particle size. On the other hand, volume ratio of oil phase to water one in primary emulsion affected the final particle size, which seemed to be related to the local PLGA concentration in w 1 /o emulsions. That is, the particle size increased as the volume ratio of w 1 phase against oil phase, w 1 /o (v/v), increased. The loading efficiency, however, was not affected by the volume ratio of w 1 /o (v/v), but affected by Blue Dextran concentration in w 1 phase. Higher loading efficiency was observed in PLGA microspheres prepared from w 1 phase containing lower concentration of Blue Dextran. Blue Dextran solution (inner water phase) with the lower viscosity may result in the lower leakage ratio of Blue Dextran during the preparation procedure. Increases in concentration and molecular weight of PLGA made particle size larger.
Huw A. John - One of the best experts on this subject based on the ideXlab platform.
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Retardation of serum albumin migration in native polyacrylamide gel electrophoresis by the incorporation of Blue Dextran in the gel matrix.
Electrophoresis, 1993Co-Authors: Alan D. Pemberton, Huw A. JohnAbstract:Blue Dextran was incorporated into the stacking layer of one-dimensional polyacrylamide gels to prevent the migration of albumin into the resolving gel during the electrophoresis of native plasma samples. Human and horse plasma proteins normally masked by albumin were revealed by this method.
John P. Kampine - One of the best experts on this subject based on the ideXlab platform.
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Use of Blue Dextran for measuring changes in perfused vascular surface area in lungs.
American Journal of Physiology-Heart and Circulatory Physiology, 1992Co-Authors: David L. Roerig, Christopher A. Dawson, Susan B. Ahlf, Robert D. Bongard, John H. Linehan, John P. KampineAbstract:We investigated the uptake and efflux of Blue Dextran in the isolated perfused rabbit lung. Blue Dextran is a high-molecular-weight glucose polymer (original mol wt 2 x 10(6) g/mol) containing covalently bonded Reactive Blue 2 dye (approximately mmol/g Dextran). This Blue dye is known for its high binding affinity to a wide variety of proteins, with a particularly high affinity for serum albumin. In isolated rabbit lungs perfused with a protein-free perfusate, both bolus injection and recirculation of Blue Dextran revealed a rapid saturable uptake. Once the lungs were loaded with Blue Dextran, efflux of the Blue Dextran accumulated in the lungs could be induced by addition of bovine serum albumin (BSA) to the recirculating perfusate. The amount of BSA-induced efflux of Blue Dextran from the lung was independent of perfusate flow. When the left pulmonary artery was ligated after the lungs had been loaded with Blue Dextran, the dye-induced BSA efflux was only about 50% of normal. Release of the ligature so that both lungs were perfused resulted in efflux of the remaining Blue Dextran. The combination of high airway pressure and low flow also reduced the dye efflux, and the effect was reversed by reducing the airway pressure. With the assumption that the high average molecular weight of Blue Dextran confines this molecule to interaction with proteins on the vascular surface, the results of this study suggest that Blue Dextran uptake and its BSA-induced efflux are proportional to the perfused vascular surface area in the lung.