Avaliação cinética e potencial do Nb2O5 obtido a partir de um complexo de nióbio para formação do oleato de metila através da reação de esterificação do ácido oleico

Among the heterogeneous catalysts materials made from niobium show up as an alternative to meet the demand of catalysts for biodiesel production. This study aims to evaluate the potential of a heterogeneous catalyst derived from a complex of niobium in the reaction of methyl esterification of oleic acid. The catalyst was synthesized after calcination at different temperatures of a niobium complex ((NH4)3[NbO(C2O4)3].H2O) generating a niobium oxide nanostructure with a different commercial niobium oxide used to synthesize the complex. The commercial niobium oxide, the complex niobium and niobium catalyst were characterized by thermogravimetry (TG and DTA), surface area analysis (BET), scanning electron microscopy (SEM) and X-ray diffraction (XRD), showing the catalyst has researched morphological and crystallographic indicating a catalytic potential higher than that of commercial niobium oxide characteristics. Factorial with central composite design point, with three factors (calcination temperature, molar ratio of alcohol/oleic acid and mass percentage of catalyst) was performed. Noting that the optimal experimental point was given by the complex calcination temperature of 600°C, a molar ratio alcohol/oleic acid of 3.007/1 and the catalyst mass percentage of 7.998%, with a conversion of 22.44% oleic acid in methyl oleate to 60 min of reaction. We performed a composite linear and quadratic regression to determine an optimal statistical point of the reaction, the temperature of calcination of the complex at 450°C, the molar ratio of alcohol/oleic acid 3.3408/1 and mass percentage of catalyst of 7.6833% . Kinetic modeling to estimate parameters for heterogeneous catalysis it set well the experimental results with a final conversion of 85.01% with 42.38% of catalyst and without catalyst at 240 min reaction was performed. Allowing to evaluate the catalyst catalytic studied has the potential to be used in biodiesel production

Structure and viscoelastic behavior of pharmaceutical biocompatible anionic microemulsions containing the antitumoral drug compound doxorubicin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural Properties Induced by the Composition of Biocompatible Phospholipid-Based Microemulsion and Amphotericin B Association

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Doxorubicin biocompatible O/W microemulsion stabilized by mixed surfactant containing soya phosphatidylcholine

Microemulsions (ME) containing soya phosphatidylcholine (SPC/polyoxyethylenglycerol trihydroxystearate 40 (EU)/sodium oleate (SO) as surfactant cholesterol (CHO) as oil phase and aqueous buffer were studied. Pseudo-ternary phase diagrams of the investigated systems were obtained at constant SPC/EU/SO weight ratio 3.5:3.5:3.0 by titration, in order to characterize the proportions between the components to form clear systems. The dynamic light scattering results showed that the size of the oil droplets decreases significantly with the ratio of surfactant/oil phase added to system. Depending on the composition ME system could exhibit a thixotropic behavior. The apparent viscosity increased 25- and 13-folds with cholesterol concentration for drug-free and drug-load ME, respectively. It was also verified that the octanol/aqueous buffer partition coefficient (K-O/B) of doxorubicin (DOX) was pH dependent increasing abruptly above pH 6.0. It was possible to incorporate 2.24 mg/ml of DOX into ME. The incorporation of DOX in the ME systems increased the droplets size for all surfactant concentrations used in the system. The results suggest that DOX interacts with the microstructure of the ME at the studied pH increasing significantly the drug solubility. It was possible to conclude that the investigated ME can be a very promising vehicle as drug-carrier for administration of doxorubicin. (c) 2006 Elsevier B.V. All rights reserved.

Relationship between structural features and in vitro release of doxorubicin from biocompatible anionic microemulsion

In this work structural features of anionic microemulsions, containing the pharmaceutical biocompatible components soya phosphatidylcholine (SPC), eumulgin HRE 40 (EU) and sodium oleate (SO) as surfactant, cholesterol (CHO) as oil phase and aqueous buffer were studied. Microemulsions were formulated with and without the antitumor drug doxorubicin (DOX). The various microstructures characterized in the pseudo-temary phase diagram were analyzed by polarized light microscopy, small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD) as well as by their ability to incorporate and release DOX. The experimental results demonstrated a correlation between the composition, the structural features and drug delivery. It was found that at higher cholesterol contents, the crystallization of CHO polymorph phases changed the mobility of DOX molecules. Droplets were formed with short-range spatial correlation from a microemulsion (ME) with a low surfactant:oil ratio. More ordered structures with lamellar arrangements formed by the increasing of the CHO proportions in the formulation may be due to CHO crystallization. The in vitro release of DOX showed that the presence of a high content of crystalline CHO prolongs the release of DOX from ME. The retention of DOX in the internal oil phase of the ME may modulate the drug release for a prolonged time. These results clearly demonstrate the potential of ME as a drug-delivery system. (c) 2007 Elsevier B.V. All rights reserved.

Effect of chemical pretreatment on the physical properties of dehydrated grapes

The effects of chemical pretreatment and air drying temperature on drying kinetics, shrinkage, density and rehydration ratio of grapes were determined at various moisture contents. It was observed that the chemical pretreatment employed - a solution of 2% CaCO3 with 0 to 3% ethyl oleate - increased considerably the drying rate. It was established that the shrinkage increased with drying temperature between 40 to 80 degrees C and decreased with increasing concentration of ethyl oleate in the chemical pretreatment solution.

Estudo das alterações eletrocorticográficas na insuficiência hepática aguda experimental.

The aim of this study was to test the application and value of electrocorticography (ECG) in the early diagnosis and characterization of electrocorticograms changes on experimental fulminant hepatic failure (FHF). Our material was composed of two groups of guinea pigs: a) ethanolamine group--42 animals with FHF induced by intrabiliary injection of 2.5 ml of monoethanolamine oleate; b) control group--10 animals submitted to intrabiliary injection of 2.5 ml of saline. Electrocorticograms recordings were taken in both groups with the electrodes implanted on the parieto-occipital regions of the skull. The hepatic failure was characterized by clinical manifestations, serum biochemical tests and histopathological findings. In the early hepatic coma the electrocorticograms could not be unequivocally distinguished from normal pattern, and alpha rhythm was recognizable in most animals. With further deterioration of the clinical condition the tracing showed progressive slowness of the normal rhythm, increased voltage and triphasic waves followed by suppression of electrical activity preceding the animal death. The electrocorticography was not suitable for the early diagnosis of hepatic coma, since the ECG alterations became evident only in overt coma. However the method could be useful for the characterization of cerebral disorders and the study of the pathogenesis of fulminant hepatic failure.

Dispersed lipid liquid crystalline phases stabilized by a hydrophobically modified cellulose

Aqueous dispersions of monoolein (MO) with a commercial hydrophobically modified ethyl hydroxyethyl cellulose ether (HMEHEC) have been investigated with respect to the morphologies of the liquid crystalline nanoparticles. Only very low proportions of HMEHEC are accepted in the cubic and lamellar phases of the monoolein-water system. Due to the broad variation of composition and size of the commercial polymer, no other single-phase regions were found in the quasi-ternary system. Interactions of MO with different fractions of the HMEHEC sample induced the formation of lamellar and reversed hexagonal phases, identified from SAXD, polarization microscopy, and cryogenic TEM examinations. In excess water (more than 90 wt %) coarse dispersions are formed more or less spontaneously, containing particles of cubic phase from a size visible by the naked eye to small particles observed by cryoTEM. At high polymer/MO ratios, vesicles were frequently observed, often oligo-lamellar with inter-lamellar connections. After homogenization of the coarse dispersions in a microfluidizer, the large particles disappeared, apparently replaced by smaller cubic particles, often with vesicular attachments on the surfaces, and by vesicles or vesicular particles with a disordered interior. At the largest polymer contents no proper cubic particles were found directly after homogenization but mainly single-walled defected vesicles with a peculiar edgy appearance. During storage for 2 weeks, the dispersed particles changed toward more well-shaped cubic particles, even in dispersions with the highest polymer contents. In some of the samples with low polymer/MO ratio, dispersed particles of the reversed hexagonal type were found. A few of the homogenized samples were freeze-dried and rehydrated. Particles of essentially the same types, but with a less well-developed cubic character, were found after this treatment. © 2007 American Chemical Society.

Desenvolvimento e análise estrutural de microemulsões lipídicas contendo a substância antitumoral metiljasmonato. Estudos da atividade antiproliferativa in vitro, liberação in vitro e toxicidade aguda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação hemodinâmica de equinos com oclusão jugular por trombose induzida submetidos a exercício físico e teste da terapia com estreptoquinase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complexos de inclusão de anfotericina B com derivados de ciclodextrinas e sua incorporação em microemulsões lipídicas biocompatíveis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Formulação e caracterização físico-química e biofarmacêutica de microemulsões lipídicas contendo doxorrubicina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Reproducible Venous Thrombosis Model in Horses Induced by the Combination of an Endothelial Lesion and Blood Flow Stasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nanostructured Lipid Systems as a Strategy to Improve the in Vitro Cytotoxicity of Ruthenium(II) Compounds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)