Extended Hildebrand solubility approach and Yalkowsky-Roseman mode l for estimating the solubility of sulfadiazine and sulfamethazine in some {ethylene glycol (1) + water (2)} mixtures at several temperatures

SUMMARY Aim: extended Hildebrand Solubility Approach (EHSA) and Yalkowsky Roseman (YR) were applied to evaluate the solubility of sulfadiazine, and sulfamethazine in ethylene glycol + water mixtures. Methodology: reported experimental equilibrium solubilities and some fusion properties of these drugs were used for the calculations. Results: a good predictive character of EHSA (with mean deviations lower than 3.0%) were found by using regular polynomials in order two correlating the inter-action parameter W with the Hildebrand solubility parameter of solvent mixtures without drug; however, the results obtained from YR model show relatively high deviations greater than 50%.

Objetivo: aplicar los enfoques de los modelos de Solubilidad Extendido de Hildebrand (EHSA) y Yalkowsky Roseman (YR) para evaluar la solubilidad de sulfadiazina y sulfametazina en mezclas de etilenglicol + agua. Metodología: para los cálculos se utilizaron las solubilidades experimentales en equilibrio reportadas y algunas propiedades de fusión de estos fármacos. Resultados: en particular, se encontró un buen carácter predictivo de EHSA (con desviaciones medias inferiores al 3,0%) utilizando polinomios regulares en orden dos correlacionando el parámetro de interacción W con el parámetro de solubilidad de Hildebrand de mezclas de disolventes sin fármaco; sin embargo, los resultados obtenidos del modelo YR muestran desviaciones relativamente altas superiores al 50%.

Objetivo: aplicar as abordagens dos modelos de Solubilidade Estendida de Hildebrand (EHSA) e Yalkowsky Roseman (YR) para avaliar a solubilidade de sulfadiazina e sulfametazina em misturas de etilenoglicol + água. Metodologia: as solubilidades de equilíbrio experimental relatadas e algumas propriedades de fusão dessas drogas foram usadas para os cálculos. Resultados: em particular, foi encontrado um bom caráter preditivo de EHSA (com desvios médios menores que 3,0%) usando polinômios regulares na ordem dois, correlacionando o parâmetro de interação W com o parâmetro de solubilidade de Hildebrand de misturas de solventes sem fármaco; no entanto, os resultados obtidos com o modelo YR mostram desvios relativamente altos superiores a 50%.

Measurement and correlation of solubility of ethylparaben in pure and binary solvents and thermodynamic properties of solution / Determinación y correlación de la solubilidad del etilparabeno en disolventes puros y binarios y propiedades termodinámicas de solución

SUMMARY Solubility data of bioactive compound such as ethylparaben (EtP) are important for the scientific and community. Therefore, in present study, solubility, solution thermodynamics and solute-solvent interactions (at molecular level) of EtP in nine cosolvent mixtures (1-propanol {n-PrOH) (1) + methanol (MeOH) (2)} including pure solvent (methanol and 1-propanol) at three different temperatures, i.e. (T = 283.2 K, 298.2 K, and 313.2 K) and constant pressure (p = 0.1 MPa) were studied. Experimental solubility of EtP (expressed in mole fraction) was observed highest in n-PrOH at 313.2 K, so, mole fraction solubility of EtP (x3) increases when temperature arises and increases with n-PrOH proportion increasing. Ideal solubilities of EtP were estimated using their thermal parameters at three different temperatures. Ideal solubilities of EtP were observed similar to experimental solubilities of EtP at each temperature. With the help of ideal solubilities of EtP, activity coefficients were estimated. Based on estimated values of activity coefficients, highest interactions at molecular level were observed in rich-MeOH mixtures. Apparent thermodynamic analysis data showed endothermic and enthalpy-driven dissolution of EtP in each solvent and mixture studied. Solubility behavior was adequately correlated by means of the van't Hoff and Yalkowsky-Roseman models combined.

RESUMEN La solubilidad de compuestos bioactivos como el etilparabeno (EtP) es importante para la comunidad científica. Por lo tanto, en el presente estudio se reportan la solubilidad, termodinámica de solución e interacciones soluto-solvente (a nivel molecular) del EtP en nueve mezclas de cosolventes {1-propanol (n-PrOH) (1) + metanol (MeOH) (2)} incluyendo los solventes puros (metanol y 1-propanol) a tres temperaturas diferentes, (T = 283,2 K, 298,15 K y 313,2 K) y a presión constante ( p = 0,1 MPa). La solubilidad experimental más alta del EtP (expresadas en fracción molar) se registró en n-PrOH a 313,15 K, así, la solubilidad en fracción molar de EtP aumenta cuando la temperatura aumenta y la proporción de n-PrOH aumentan. Las solubilidades ideales de EtP se estimaron utilizando los parámetros térmicos a tres temperaturas diferentes. Las solubilidades ideales de EtPa son similares a las solubilidades experimentales de EtP a cada temperatura. A partir de las solubilidades ideales de EtP se estimaron los coeficientes de actividad y sobre la base de los valores estimados de los coeficientes de actividad, se define que las interacciones más altas a nivel molecular se registraron en mezclas ricas en MeOH. Los datos aparentes del análisis termodinámico mostraron un proceso endotérmico con conducción entálpica para el EtP cada uno de los solventes y mezclas de solventes estudiados. El comportamiento de solubilidad se correlacionó adecuadamente mediante los modelos de van't Hoff y Yalkowsky-Roseman combinados.

Laccase produced by a thermotolerant strain of Trametes trogii LK13

Thermophilic and thermotolerant micro-organisms strains have served as the natural source of industrially relevant and thermostable enzymes. Although some strains of the Trametes genus are thermotolerant, few Trametes strains were studied at the temperature above 30 °C until now. In this paper, the laccase activity and the mycelial growth rate for Trametes trogii LK13 are superior at 37 °C. Thermostability and organic cosolvent tolerance assays of the laccase produced at 37 °C indicated that the enzyme possessed fair thermostability with 50% of its initial activity at 80 °C for 5 min, and could remain 50% enzyme activity treated with organic cosolvent at the concentration range of 25%–50% (v/v). Furthermore, the test on production of laccase and lignocellulolytic enzymes showed the crude enzymes possessed high laccase level (1000 U g−1) along with low cellulose (2 U g−1) and xylanase (140 U g−1) activity. Thus, T. trogii LK13 is a potential strain to be applied in many biotechnological processes.

Preparation process of apigenin particles by supercritical CO2 anti-solvent method / 中草药

Objective: To prepare the apigenin particles by supercritical CO2 anti-solvent technology, to optimize the preparation process of apigenin particles on the basis of single factor experiments using the average particle size as evaluation index through orthogonal test design, and to investigate the in vitro dissolution rate. Methods: The particle size distribution, scanning electro- microscope (SEM) analysis, infrared spectrum (IR), and differential scanning calorimetry (DSC) were used to validate the selected process. The external dissolution rates of apigenin ingredient and apigenin particles of the optimal process were tested to speculate the bioavailability of apigenin. Results: The optimal process conditions by orthogonal test were set as follows: The proportion of acetone and dimethyl sulfoxide (DMSO) was 24:1, temperature was 40°C, pressure was 10 MPa, solution volumetric flow rate was 2.0 mL/min, and mass concentration of apigenin was 8 mg/mL. Under the optimal conditions, the volume average particle size was obviously smaller than that of ingredient. And the shapes of apigenin were irregular. FTIR and DSC analyses showed that the chemical structure did not change. The results showed that the in vitro dissolution rate of apigenin particles of the optimal process was significantly larger than that of apigenin ingredient. Conclusion: The supercritical CO2 anti-solvent technology is feasible to prepare apigenin particles and promote its bioavailability, and it provides a reference basis for preparing ultrafine particles.

Effects of components on and predictive modeling of microemulsion phase behavior in nonionic systems.

This study aimed to investigate phase behaviors, to study effects of cosolvent addition on size of microemulsion regions and to propose modified logistic regression which could describe microemulsion regions in nonionic systems. The systems composed of rice bran oil (RBO) or isopropyl palmitate (IPP), various ratios of sorbitan monooleate (SMO) and polyoxyethylene 20 sorbitan monooleate (PSMO) mixtures, water and isopropyl alcohol (IPA) or propylene glycol (PG) were studied for their microemulsion regions obtained on the phase diagrams. Concept of modified logistic regression was used to predict probability of microemulsion formation and size of microemulsion regions in the systems. It was found that both oil and cosolvent types affected on microemulsion formation. A system composed of IPP, 2:1 water:IPA, and 1:1 SMO:PSMO could provide the largest microemulsion region. However, the purposed modified logistic regression could be used consistently for only one system of the total four systems due to the faceted shape of microemulsion-zone.

Extracción de paaguicidas en suelo empleando dióxido de carbono supercrítico-cosolventes / Extracton of pessticides in soil using supercritical carbon dioxide -co-solvents / Extracço de pragguicidas em solo utilizndo dióxido de carbono supercriitica- co-solvente

En este estudio se evaluó la eficiencia de tres solventes orgánicos (acetato de etilo, metanol y acetona) empleados como cosolventes en la extracción con fluidos supercríticos (EFS) de una mezcla de plaguicidas con diferentes características fisicoquímicas. Los análisis se realizaron por medio de cromatografía de gases con detección simultánea por microcaptura electrónica (µECD) y nitrógeno-fósforo (NPD) acoplados en paralelo. Se hicieron extracciones a muestras de suelo fortificadas con los plaguicidas empleando dióxido de carbono supercrítico (CO2SC) como fase extractante a 35 °C y 14 MPa adicionando 10 mL de cada cosolvente. Se encontró que el metanol ofrece la mayor eficiencia en el proceso de extracción obteniendo valores de recuperación entre 51,24 y 123,50%.

In this study, three organic solvents (ethyl acetate, methanol and acetone) were used as cosolvent in supercritical fluid extraction (SFE) of a mixture of pesticides with different physical and chemical properties present in soil. These pesticides were determined by gas chromatography with electronic microcapture detector (µECD) and nitrogen-phosphorus detector (NPD), coupled in parallel. The extractions were performed on spiked soil samples using supercritical carbon dioxide (CO2SC) as the extracting phase to 35 °C and 14 MPa, using 10 mL of each cosolvent and it was found that methanol offers the greatest efficiency in the extraction process obtaining recovery values between 51.24 and 123.50%.

No estudo se avaliou três solventes orgânicos (acetato de etila, metanol e acetona), como cosolvente em a extração com fluido supercrítico (EFS) de uma mixtura de praguicidas com diferentes propiedades física e química (organoclorados, or-ganofosforados, organonitrogenados e piretróides) presentes no solo, determinadas por cromatografia gaseosa com in-jecção pulsed splitless e detecção simultânea por µECD e nitrogênio-fósforo (NPD) acoplados em paralelo, as extrações foram realizadas em amostras de solo fortificadas, usando dióxido de carbono (CO2), como a fase de extração a 35 °C 14 MPa, com 10 mL de cada solvente e constatamos que o metanol oferece a maior eficiência da remoção de todos os pragui-cidas e obter recuperação valores entre 51,24 e 123,50%.

Modelos de Yalkowsky-Roseman y Jouyban-Acree en la estimación de la solubilidad del ketoprofeno en algunas mezclas cosolventes propilenoglicol + agua / Yalkowsky-Roseman and Jouyban-Acree models on estimating the solubility of ketoprofen in some propylene glycol + water cosolvent mixtures

En la presente investigación se evaluó la validez de una adaptación específica del modelo de Jouyban-Acree ( J-A), en comparación con la utilidad de la ecuación logarítmica-lineal de solubilidad propuesta por Yalkowsky y Roseman (Y-R), para estimar la solubilidad del ketoprofeno (KTP) en algunas mezclas cosolventes propilenoglicol + agua, en función de la composición cosolvente y de la temperatura, en el intervalo entre 293,15 y 313,15 K. Los modelos de J-A y Y-R requieren únicamente de los valores experimentales de la solubilidad en equilibrio del fármaco en los solventes puros a las diferentes temperaturas de interés. Desafiando las ecuaciones frente a valores experimentales de solubilidad, se encontró que los valores predichos por los dos modelos semiempíricos son bastante similares entre sí (difiriendo en un promedio de 0,05 unidades logarítmicas naturales), y que además, presentan algunas desviaciones notorias respecto a los valores experimentales, en particular con el modelo Y-R. Estos resultados demostraron la necesidad de mejorar las estrategias teóricas para la estimación de esta propiedad, y así mismo, demostraron la importancia de la determinación experimental de la solubilidad, en función de la temperatura, en todas aquellas mezclas cosolventes que puedan ser útiles durante el proceso de diseño de productos farmacéuticos.

The feasibility of a trained version of the Jouyban-Acree ( J-A) model was evaluated in this research to predict the solubility of ketoprofen (KTP) in some propylene glycol + water cosolvent mixtures. The usefulness of the solubility log-linear equation proposed by Yalkowsky and Roseman (Y-R) was also evaluated for the same drug in this cosolvent system. The solubility estimation was studied as a function of temperature and cosolvent composition. The J-A and Y-R models require only the experimental equilibrium solubility values in the pure solvents at all the temperatures evaluated. The estimated solubility values obtained by using both semiempiric models were similar between them (differing in 0.05 natural logarithmic units), but they present notorious deviations with respect to the experimental values, in particular the Y-R model. These results demonstrated that it is necessary to improve the theoretical strategies for estimating this property, and on the other hand, they also demonstrated the great importance of the experimental determination of drugs solubility in those cosolvent mixtures useful in dosage forms design.

Validez del métddo extendido de hildebrand en l predicción de las solubilidadees de ibuprofén y naproxén en mezclas propilenoglicol + etanol / Valdity of the eextnded hildebrand solubility approach in the estiimation of ibuprofen and naproxen solubilities in propylene glycol + ethanol mixtures / Validez da aroxiimação ampliada da solubilidde de hildebrand na estimação dda solubilidade de ibuprofen e de naproxen em misturas do propileno glicol + etanol

En la presente investigación, el Método Extendido de Solubilidad de Hildebrand (MESH), desarrollado por Martin y cols . se ha aplicado al estudio de la solubilidad del ibuprofén (IBP) y del naproxén (NAP) en mezclas binarias propilenoglicol + etanol a 298,15 K ± 0,05 K. Se han utilizado los volúmenes molares aparentes de los solutos y las fracciones volumétricas de los solvente en las respectivas soluciones saturadas. Se encontró una adecuada capacidad predictiva del MESH al utilizar modelos polinómicos regulares de cuarto orden para IBP y de tercer orden para NAP, relacionando el parámetro de interacción W con el parámetro de solubilidad de las mezclas solventes. Sin embargo, las desviaciones obtenidas en la solubilidad estimada, respecto a los valores experimentales, fueron de magnitud semejante a las obtenidas al calcular esta propiedad directamente, utilizando regresiones empíricas de la solubilidad experimental de los fármacos en función del parámetro de solubilidad de las mezclas cosolventes.

In this work the Extended Hildebrand Solubility Approach (EHSA) developed by Martin et al ., has been applied to evaluate the solubility of ibuprofen (IBP) and naproxen (NAP) in propylene glycol + ethanol cosolvent mixtures at 298.15 K ± 0.05 K. Apparent molar volumes of the solutes and the volumetric fraction of the solvents in the saturated solutions were employed. A good predictive capacity of EHSA was found using regular polynomial models of order four for IBP and of order three for NAP, when the W interaction parameter was related to the solubility parameter of the solvent mixtures. Nevertheless, the deviations obtained for the estimated solubility respect to experimental solubility were of the same order as compared with those obtained directly using empiric regressions of the experimental solubilities as a function of the cosolvent solubility parameters.

Neste trabalho a aproximação ampliada da solubilidade de Hildebrand (AASH) desenvolvida por Martin e colaboradores, foi aplicada para avaliar a solubilidade de ibuprofeno e naproxeno em misturas cosolvente do propileno glicol + etanol do 298,15 K ± 0.05 K. Os volumes molares aparentes dos solutos e a fração volumétrica dos solventes nas soluções saturadas foram empregados. Uma boa capacidade predictiva de AASH foi encontrada do usar um modelo polinomial regular em ordem quatro para IBP e em ordem três para a NAP, quando o parâmetro da interação W foi relacionado ao parâmetro da solubilidade das misturas dos solventes. Não obstante, os desvios obtidos na solubilidade estimada respeito aos valores experimentais foram na mesma ordem comparada com as aquelas obtidas diretamente usando regressões empíricas das solubilidades experimentais em função dos parâmetros da solubilidade dos cosolventes.