Search

The aim of this study was to encapsulate ivermectin in poly(methyl methacrylate) (PMMA) using a supercritical antisolvent (SAS) process. The Box–Behnken method was employed for obtaining a lower average particle diameter (dexp) of ivermectin-impregnated PMMA nanoparticles. The encapsulation efficiency was 73.08 ± 3.22%, and the nanoparticles were characterized morphologically, thermally, and conformationally using the following techniques: scanning electron microscopy, differential thermogravimetric analysis, and attenuated total-reflectance Fourier-transform infrared spectroscopy. The in vitro release kinetics showed that the drug had a controlled release of approximately 100 h, and that the Higuchi, Peppas–Sahlin, and Korsmeyer–Peppas models were able to correctly describe the drug diffusion processes. The precipitation kinetic parameters were determined from dexp using the population balance equation. This equation showed that the nucleation rate and nucleation population density were dominant for R6 (9 MPa, 313.15 K, 3 mL/min), and that the growth rate had little variation across all experiments.

For potential application to the controlled release of ivermectin from nanoparticle preparations, this study discloses experimental data on the phase transitions in the CO2, acetone, and ivermectin system subjected to high pressures. The data were acquired via the static synthetic method with a variable-volume view cell in the temperature range of 303.15-333.15 K at pressures up to 10 MPa using three concentrations of ivermectin B1a in acetone (0.029, 0.043, and 0.058 mol·kg-1) and CO2 molar fractions of 0.3-0.9. Vapor-liquid-type phase transitions were observed, characterized as bubbles in the presence or absence of a solid phase. A solid phase was formed for all ivermectin B1a concentrations evaluated in this study. Determination of the region of precipitation of ivermectin is important for identifying the concentration of the acetone/ivermectin mixture where CO2 will act strongly as an antisolvent. Thermodynamic modeling was performed by considering the system as pseudo-ternary based on the low concentration of ivermectin B1a in the system. Thermodynamics modeling using the Peng-Robinson cubic state equation with the van der Waals mixing rule (PR-vdW2) adequately described the experimentally observed trends.

Photocatalytic activity of TiO2 nanoparticles is highly dependent on their phase composition. The coexistence of anatase and rutile phases in a single nanoparticle eases the electron transfer process between the phases, and favors the separation of photogenerated pairs. In this work, highly photoactive mixed-phase TiO2 nanostructures were prepared by supercritical antisolvent precipitation (SAS), an environmentally friendly technology. It is shown here that this methodology has the remarkable ability to produce highly porous (515 m2/g) and crystalline TiO2 nanoparticles. The phase composition of as-prepared TiO2 samples can be tailored through annealing process. Several mixed-phase TiO2 samples were tested to assess the correlation between photocatalytic activity and phase composition. The photocatalytic performance is strongly affected by the anatase-rutile ratio, since the synergism between phases enhances the charge separation, reducing the recombination effect of the photogenerated pairs (e−/h+). It was found that the nanocatalyst composed by 7.0 wt% of rutile phase and 93.0 wt% of anatase phase, named as TiO2_650, presented the highest photodegradation for both methyl orange (MO) and methylene blue (MB) dyes. Interestingly, TiO2 samples prepared by SAS have superior photoactivity than the benchmark photocatalyst names as P25, which is a widely used TiO2 material composed of anatase and rutile phases.

O objetivo principal deste estudo foi produzir e otimizar nanopartículas de polimetil metacrilato (PMMA) via processo emulsão simples seguida de evaporação. Os compostos utilizados foram clorofórmio, lecitina, progesterona, ivermectina e PMMA na fase orgânica e água e poliacetato de vinila (PVA) na fase aquosa. As NPs/P4 tiveram um diâmetro de 154,3 ± 0,1 nm e as NPs/IM 184,1 ± 0,1. A otimização desse diâmetro ocorreu por uma superfície de resposta de Box-Behnken. As partículas formadas foram caracterizadas pelas técnicas de MET, MEV, TGA/DTA e FT-Raman para a determinação da morfologia, resistência térmica e elucidar sua estrutura conformacional.

In this work, was investigate the effect of the molecular weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) on the preparation of medroxyprogesterone acetate (MPA)⿿encapsulated polymeric nanoparticles (PNPs) using the supercritical fluid extraction of emulsions (SFEE) technique. Particles with diameters between 850 nm⿿183 nm were obtained using PHBV of molar mass reduced and variable between 210 kDa to 14 kDa, thus establishing a direct relation between the size of the PNPs prepared with SFEE and the molar mass of the polymer. These results were contrasted with those obtained with the conventional emulsion solvent evaporation (ESE) technique. PNPs prepared by SFEE were observed to be smaller than those produced by ESE, for all polymer molecular weights (MW) studied. The encapsulation efficiency (EE%) of MPA in the PNPs prepared with the SFEE technique, and with the lowest MW PHBV was determined to be 70%. The in vitro release kinetics for this system indicated that the mean time for 35% release of MPA was 18 h. Both a first and a second-order kinetics models provide a good fit to the release profile of MPA from the PHBV PNPs. Cellular viability results indicate low toxicity profiles of the PHBV PNPs prepared with the SFEE technique, even at high PNP concentrations.

This study reports the oil extraction efficiency using Moringa oleifera seed and pressurized propane; a new experimental data for phase transition of the binary system {n-propane + Moringa oleifera oil} and the profile of fatty acid compositions of the extracted Moringa oil. During the present study, the knowledge of the phase behaviour proved to be of great importance to optimize supercritical extraction using pressurized fluid. This project also presents a comparison with the classical Soxhlet method including mathematical modelling of kinetic curves of extraction. The extraction experiments were performed in the temperature and pressure ranges of 303–333 K and 2.5–12 MPa, respectively, at a constant flow rate of 1.0 cm3/min of n-propane. All the conditions applied during the n-propane extraction process provided similar or higher yields (32.8 to 42.1%) compared to extractions using n-hexane (42.6%) and supercritical carbon dioxide (SC-CO2) (37.8%). In addition, phase transition study for the {Propane (1) + Moringa oleifera oil (2)} system was performed using a variable volume cell and the static synthetic method in a temperature range of 303–343 K, pressures up to 3.23 MPa and n-propane mass fraction between 0.2 and 0.8. Vapour-liquid (VLE), liquid-liquid (LLE) and vapour-liquid-liquid (VLLE) phase transitions were observed at relatively low pressures. The fatty acid profiles of the extracted Moringa oils were evaluated using gas chromatography. They all have very close composition regardless of the solvent used and oleic acid as the major component (≈76%). The Sovova mathematical model indicated a good fit for all the conditions investigated. This article is protected by copyright. All rights reserved

New experimental data were measured for phase transition of the binary system CO2 + black sesame oil. A variable volume cell was employed using the static synthetic method in a temperature range of 303–333 K, pressures up to 20 MPa, and CO2 mass fractions between 0.12–0.39 g/g. For mass fractions > 0.39, phase transition data were not measured due to pressure limitations of the high-pressure system used. Vapour-liquid transitions (VLE) of bubble point (BP) were determined. Phase transition data of CO2 + black sesame oil were compared to reported data from the literature involving CO2 and similar oils. The trend of the phase transition behaviour between all systems compared was similar. Phase equilibrium data obtained experimentally were successfully modelled with the Peng-Robinson equation of state (PR-EoS) combined with the van der Waals mixing rule (PR-vdW2) and Wong-Sandler mixing rule (PR-WS).

This paper reports experimental phase equilibrium data for the systems {CO2 (1) + solketal (2)} and {CO2 (1) + solketal (2) + oleic acid (3)}. The phase transition pressure measurements for ternary mixtures were carried out by injecting a known amount of carbon dioxide into a mixture with fixed molar ratios of the two other components (0.75 solketal + 0.25 oleic acid). A variable-volume cell with a front window was used for the measurements. The experimental data were measured over the temperature range from (308 to 338) K and at pressures of up to 20 MPa. Bubble point conditions were measured for the binary system {CO2 (1) + solketal (2)}, whereas bubble and dew point conditions were measured for the ternary system {CO2 (1) + solketal (2) + oleic acid (3)}. Phase equilibrium modeling with the Peng–Robinson equation of state was successful in describing the behavior of the investigated systems.

In this work the vapor–liquid equilibrium for the {CO2(1) + dichloromethane(2) + medroxyprogesterone(3)} system were measured for different concentrations of medroxyprogesterone in dichloromethane (0.01 g mL−1 and 0.02 g mL−1) at temperatures ranging from (303 to 333) K and pressure up to 8.6 MPa. The experimental data were obtained using a visual synthetic static method employing a variable volume cell. The liquid–vapor transitions were classified as a bubble points and dew points in the presence or absence of solid phase. The experimental vapor–liquid equilibrium data were satisfactory correlated using the Peng–Robinson equation of state with a quadratic mixing rule.

New data on phase equilibria for Sacha inchi seed oil in carbon dioxide have been measured using a variable volume cell phase equilibria system at temperatures of 303, 313 and 323 K and at pressures ranging from 4.3 to 27.7 MPa. The CO2 mole fraction varied from 0.7488 to 0.9997. At the studied concentrations, phase transitions of vapor-liquid, liquid-liquid-vapor and liquid-liquid were observed. Sacha inchi oil contains 47% of omega-3 fatty acids, with a ratio of 0.76:1 for omega-6:omega-3, which is good for human health. The Peng-Robinson equation of state was used to describe the experimental data. A qualitative agreement was obtained between experimental and calculated data for the binary system CO2 and Sacha inchi seed oil.

In the present work phase equilibrium data for the ternary systems CO2 + ethanol + curcumin and CO2 + ethyl acetate + curcumin, at different concentrations of curcumin in the organic solvent (0.01 g.cm-3, 0.005 g.cm-3 for ethanol and 0.01 g.cm-3, 0.0025 g.cm-3 for ethyl acetate) are reported. The static synthetic method, using a variable-volume view cell was employed for obtaining the experimental data in the temperature range of (303 to 333) K and pressures up to 11 MPa. Vapor-liquid phase transitions were observed as bubble and dew points for the overall compositions investigated. The phase equilibria of the ternary systems were fitted to the Peng-Robinson equation of state (PR-EoS) using only binary system information. Experimental data together with modeling results may constitute relevant information for the precipitation of curcumin using the supercritical antisolvent process.

This work reports the synthesis of particles based on poly(3-hydroxybutirate-co-3-hydroxyvalerate) (PHBV) polymer that were impregnated with progesterone. The PHBV particles were obtained by supercritical CO2 (scCO2) anti-solvent expansion (SAS). scCO2 was also used at a high pressure (25 MPa) and moderate temperature (323 K) for the impregnation of progesterone into the PHBV particles at different impregnation times. In vitro release tests showed that the half-time of progesterone release in a hydro-alcoholic medium, for the samples produced with impregnation times of 2–32 h, was 3–5 h, with the higher release times generally related to smaller impregnation times.

The survey awakened a big interest in the production of functional, such as isoflavones, with proven action on the prevention of health problems, such as cancer and cardiovascular diseases. Considering the importance of soybean supplements standardization, this study aimed identifying and quantifying the isoflavones in products sold at different pharmacies. Isoflavones samples were acquired in six different pharmacies specialized in the production of phytotherapic medications. The isoflavones were extracted, quantified and identified in HPLC. None of the samples, from different pharmacies, presented the isoflavones content presented on the label, i.e., 20 mg. In relation to the isoflavones profile, the highest levels found were of daidzein, with up to 66.8 µg, being the lowest levels the ones of genistein. Therefore, it is necessary to adopt methods of standardization and characterization of raw ensure that the content of isoflavones, because they are essential for the purposes prescribed by medical professionals

RESUMO – Este trabalho tem por objetivo a investigacao do comportamento de fases da mistura binaria {CO2(1) + Cumarina(2)} empregando o metodo estatico sintetico a partir uma celula de volume variavel com visualizacao das transicoes de fases. Os experimentos foram conduzidos nas faixas de temperatura e fracao molar de 298-338 K e 2x10 -3 -6x10 -3 , respectivamente. As transicoes de fases ocorreram em pressoes de ate 20 MPa, sendo observados equilibrios solido-fluido (ESF), solido-liquido-vapor (ESLV), liquido-vapor (ELV) e fluido-fluido (EFF).

RESUMO Este trabalho tem como objetivo a extracao e quantificacao de compostos bioativos da semente do cumaru por meio de extracao convencional (soxhlet) e supercritica utilizando dioxido de carbono e solventes modificadores. As extracoes supercriticas foram realizadas numa faixa de pressao de 180 220 bar e temperatura de 60 80oC. O planejamento experimental foi definido a partir do design fatorial fracionado (metodo Taguchi). Os extratos foram analisados por cromatografia liquida (HPLC) e gasosa com espectrofotometro de massas (GCMS). A extracao da cumarina utilizando o dioxido de carbono e modificados apresentou melhor seletividade e rendimentos em relacao a extracao convencional.

Grande parte da energia consumida no mundo provém do petróleo, do carvão e do gás natural, que devido à problemas ambientais tem suas existências limitadas. Em função disso, há uma constante busca por fontes alternativas que não competem com a alimentação humana. O biodiesel é um combustível alternativo para o diesel de petróleo, feito a partir de fontes biológicas renováveis, tais como óleos vegetais e gorduras animais. Ele é biodegradável e não tóxico, além de ser benéfico para o meio ambiente. Foi realizada em um reator contínuo a transesterificação no óleo de palma, para ocorrer produção de biodiesel, onde os triacilglicerídeos do óleo de palma reagiram com metanol na presença de um catalisador ácido heterogêneo, produzindo uma mistura de ésteres de ácidos graxos e glicerol. Utilizou-se o óleo de palma pelo seu alto rendimento de produção, onde foi encontrado conversão de 53,47% em ésteres, através da transesterificação na condição de 1:15 de óleo de palma e metanol, 105 ºC, 8g de catalisador Amberlyst® 15 e vazão de 0,7 mL/min, em um reator contínuo.

Experimental data from the phase transition of the ternary systems {CO2(1) + [0.25 monoethanolamine(2) + 0.75 ethanol(3)]}, {CO2(1) + [0.25 diethanolamine(2) + 0.75 ethanol(3)]} and {CO2(1)+ [0.25 triethanolamine(2) + 0.75 ethanol(3)]} is reported. A variable volume cell was employed using the static synthetic method in a temperature range of (313–343) K, pressures up to 14 MPa and CO2 mole fractions between 0.05 and 0.35. For xCO2 > 0.35 phase transition data could not be measured for pressures up to 35 MPa. Vapor–liquid transitions (VLE) of bubble point (BP) are determined for the three ternary systems studied. The determination of measures of the phase equilibrium of systems involving CO2 and alkanolamines are of great importance in the development of absorption processes. A great feature of alkanolamines is the possibility of capturing carbon dioxide (CO2) and promoting separation of this gas from other gas streams. Fil: Brito Guerra Neto, Dival de . Universidade Federal do Rio Grande do Norte; Brasil Fil: Ferreira Pinto, Leandro . Universidad Estadual de Maringá; Brasil Fil: Machado Giufrida, Willyan . Universidad Estadual de Maringá; Brasil Fil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Planta Piloto de Ingenieria Quimica (i). Grupo Vinculado Al Plapiqui - Investigación y Desarrollo en Tecnologia Quimica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Quimica; Argentina Fil: Cardozo Filho, Lúcio. Universidad Estadual de Maringá; Brasil Fil: Chiavone Filho, Osvaldo . Universidade Federal do Rio Grande do Norte; Brasil

This work presents new experimental phase equilibrium data for mitotane in supercritical CO 2 and mitone in supercritical CO 2 plus ethanol. The synthetic-static method in a high-pressure variable-volume view cell was used to measure the solid-fluid (SF) and the fluid-fluid (FF) equilibrium data. The phase equilibrium experiments were carried out in the temperature range from (298 to 333) K and in the pressure range from (3.44 to 21.84) MPa. The Peng-Robinson equation of state (PR-EoS) was used for describing the fluid phases, and an expression for the fugacity of pure solid mitotane was used for representing the solid phase. This made it possible to model the SF and FF equilibrium data for the CO 2 + mitotane mixtures. Fair agreement was found between experimental and calculated values. Fil: Giufrida, W. M.. Universidade Estadual de Maringá; Brasil Fil: Rodriguez Reartes, Sabrina Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Alonso, C. G.. Universidade Estadual de Maringá; Brasil Fil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Cabral, V. F.. Universidade Estadual de Maringá; Brasil Fil: Tavares, F. W.. Universidade Federal do Rio de Janeiro; Brasil Fil: Cardozo Filho, L.. Universidade Estadual de Maringá; Brasil