Solubility of cefoxitin acid in different solvent systems

International Nuclear Information System (INIS)

Yuan, Fuhong; Wang, Yongli; Xiao, Liping; Huang, Qiaoyin; Xu, Jinchao; Jiang, Chen; Hao, Hongxun

2016-01-01

Highlights: • The solubility of cefoxitin acid in different solvent systems was measured. • Three models were used to correlate the solubility data. • The dissolution enthalpy of the dissolution process was calculated. - Abstract: Cefoxitin acid is one kind of important pharmaceutical intermediate. Its solubility is crucial for designing and optimizing the crystallization processes. In this work, the solubility of cefoxitin acid in organic solvents (methanol, acetonitrile, ethanol, isopropanol, n-propanol and ethyl acetate), water and water-methanol mixtures was measured spectrophotometrically using a shake-flask method within the temperature range 278.15–303.15 K. PXRD data and the Karl Fischer method were used to verify the crystal form stability of cefoxitin acid in the solubility measuring process. The melting points, the enthalpy and entropy of fusion were estimated. Results showed that the solubility of cefoxitin acid increases with the increasing temperature in all tested solvents in this work, and the solubility of cefoxitin acid increases with the increasing methanol concentration in water-methanol mixtures. The experimental solubility values were well correlated using the modified Apelblat equation, NRTL model and CNIBS/R-K model. An equation proposed by Williamson was adopted to calculate the molar enthalpy during the dissolution process.

Solubility of nickel-cadmium ferrite in acids

International Nuclear Information System (INIS)

Vol'ski, V.; Vol'ska, Eh.; Politan'ska, U.

1977-01-01

The solubility of a solid solution of nickel-cadmium ferrite containing an excess of ferric oxide, (CdO)sub(0.5), (NiO)sub(0.5) and (Fe 2 O 3 )sub(1.5), in hydrochloric and nitric acids at 20, 40 and 60 deg C, was determined colorimetrically and chelatometrically, as well as by studying the x-ray diffraction patterns of the preparations prior to dissolution and their residues after dissolution. It is shown that cadmium passes into the solution faster than iron and nickel; after 800 hours, the solution contains 40% of iron ions and more than 80% of cadmium ions. The kinetics of ferrite dissolution is studied

Radionuclide solubility control by solid solutions

Energy Technology Data Exchange (ETDEWEB)

Brandt, F.; Klinkenberg, M.; Rozov, K.; Bosbach, D. [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research - Nuclear Waste Management and Reactor Safety (IEK-6); Vinograd, V. [Frankfurt Univ. (Germany). Inst. of Geosciences

2015-07-01

The migration of radionuclides in the geosphere is to a large extend controlled by sorption processes onto minerals and colloids. On a molecular level, sorption phenomena involve surface complexation, ion exchange as well as solid solution formation. The formation of solid solutions leads to the structural incorporation of radionuclides in a host structure. Such solid solutions are ubiquitous in natural systems - most minerals in nature are atomistic mixtures of elements rather than pure compounds because their formation leads to a thermodynamically more stable situation compared to the formation of pure compounds. However, due to a lack of reliable data for the expected scenario at close-to equilibrium conditions, solid solution systems have so far not been considered in long-term safety assessments for nuclear waste repositories. In recent years, various solid-solution aqueous solution systems have been studied. Here we present state-of-the art results regarding the formation of (Ra,Ba)SO{sub 4} solid solutions. In some scenarios describing a waste repository system for spent nuclear fuel in crystalline rocks {sup 226}Ra dominates the radiological impact to the environment associated with the potential release of radionuclides from the repository in the future. The solubility of Ra in equilibrium with (Ra,Ba)SO{sub 4} is much lower than the one calculated with RaSO{sub 4} as solubility limiting phase. Especially, the available literature data for the interaction parameter W{sub BaRa}, which describes the non-ideality of the solid solution, vary by about one order of magnitude (Zhu, 2004; Curti et al., 2010). The final {sup 226}Ra concentration in this system is extremely sensitive to the amount of barite, the difference in the solubility products of the end-member phases, and the degree of non-ideality of the solid solution phase. Here, we have enhanced the fundamental understanding regarding (1) the thermodynamics of (Ra,Ba)SO{sub 4} solid solutions and (2) the

On the solubility of nicotinic acid and isonicotinic acid in water and organic solvents

International Nuclear Information System (INIS)

Abraham, Michael H.; Acree, William E.

2013-01-01

Highlights: ► Solubilities of nicotinic acid and isonicotinic acids in organicsolvents have been determined. ► Solubilities are used to calculate Abraham descriptors for the two acids. ► These descriptors then yield water-solvent and gas-solvent partitions into numerous solvents. ► The solubility of the neutral acids in water is obtained. ► The method is straightforward and can be applied to any set of compound solubilities. -- Abstract: We have determined the solubility of nicotinic acid in four solvents and the solubility of isonicotinic acid in another four solvents. These results, together with literature data on the solubility of nicotinic acid in five other organic solvents and isonicotinic acid in four other organic solvents, have been analyzed through two linear Gibbs energy relationships in order to extract compound properties, or descriptors, that encode various solute–solvent interactions. The descriptors for nicotinic acid and isonicotinic acid can then be used in known equations for partition of solutes between water and organic solvents to predict partition coefficients and then further solubility in a host of organic solvents, as well as to predict a number of other physicochemical properties

Solubility of sparingly soluble drug derivatives of anthranilic acid.

Science.gov (United States)

Domańska, Urszula; Pobudkowska, Aneta; Pelczarska, Aleksandra

2011-03-24

This work is a continuation of our systematic study of the solubility of pharmaceuticals (Pharms). All substances here are derivatives of anthranilic acid, and have an anti-inflammatory direction of action (niflumic acid, flufenamic acid, and diclofenac sodium). The basic thermal properties of pure Pharms, i.e., melting and glass-transition temperatures as well as the enthalpy of melting, have been measured with the differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The equilibrium mole fraction solubilities of three pharmaceuticals were measured in a range of temperatures from 285 to 355 K in three important solvents for Pharm investigations: water, ethanol, and 1-octanol using a dynamic method and spectroscopic UV-vis method. The experimental solubility data have been correlated by means of the commonly known G(E) equation: the NRTL, with the assumption that the systems studied here have revealed simple eutectic mixtures. pK(a) precise measurement values have been investigated with the Bates-Schwarzenbach spectrophotometric method. © 2011 American Chemical Society

Extended solid solubility of a Co–Cr system by mechanical alloying

International Nuclear Information System (INIS)

Betancourt-Cantera, J.A.; Sánchez-De Jesús, F.; Torres-Villaseñor, G.; Bolarín-Miró, A.M.; Cortés-Escobedo, C.A.

2012-01-01

Highlights: ► Solubility of the Co–Cr system is modified by means of Mechanical Alloying (MA). ► MA induces the formation of new solid solutions of Co–Cr system in non-equilibrium. ► MA promote the formation of metastable Co–Cr phases with greater solubility. - Abstract: Mechanical alloying, MA, has been successfully used to extend the limits of solid solubility in many commercially important metallic systems. The aim of this work is to demonstrate that MA modifies the solid solubility of the Co–Cr system. Co and Cr elemental powders were used as precursors and mixed in an adequate weight ratio to obtain Co 100−x Cr x (0 ≤ x ≤ 100, Δx = 10) to study the effect of mechanical processing in the solubility of the Co–Cr system. Processing was carried out at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball:powder weight ratio of 10:1. Crystalline structure characterization of the milled powders was conducted using X-ray diffraction, and phase transformations as a function of composition were analyzed. Thermal analysis confirmed structural changes occurred in the mechanically alloyed powders. The evolution of the phase transformations with composition is reported for each composition. The results showed that after high energy ball milling for 7 h, the solid solubility between Co and Cr could be evidently extended, despite the low solid solubility at the equilibrium conditions of this system. Additionally, the micrographs of the milled powders showed that increasing composition of chromium changes the shape and size of the particles while simultaneously reducing their agglomeration; this effect is possibly attributed to the brittleness of elemental chrome.

Extended solid solubility of a Co-Cr system by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Betancourt-Cantera, J.A. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sanchez-De Jesus, F., E-mail: fsanchez@uaeh.edu.mx [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Torres-Villasenor, G. [Instituto de Investigaciones en Materiales-UNAM, Apdo. Postal 70-360, 04510 Mexico, DF (Mexico); Bolarin-Miro, A.M. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Cortes-Escobedo, C.A. [Centro de Investigacion e Innovacion Tecnologica del IPN Cda. CECATI S/N, Col. Sta. Catarina, Azcapotzalco, 02250 Mexico, DF (Mexico)

2012-07-15

Highlights: Black-Right-Pointing-Pointer Solubility of the Co-Cr system is modified by means of Mechanical Alloying (MA). Black-Right-Pointing-Pointer MA induces the formation of new solid solutions of Co-Cr system in non-equilibrium. Black-Right-Pointing-Pointer MA promote the formation of metastable Co-Cr phases with greater solubility. - Abstract: Mechanical alloying, MA, has been successfully used to extend the limits of solid solubility in many commercially important metallic systems. The aim of this work is to demonstrate that MA modifies the solid solubility of the Co-Cr system. Co and Cr elemental powders were used as precursors and mixed in an adequate weight ratio to obtain Co{sub 100-x}Cr{sub x} (0 {<=} x {<=} 100, {Delta}x = 10) to study the effect of mechanical processing in the solubility of the Co-Cr system. Processing was carried out at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball:powder weight ratio of 10:1. Crystalline structure characterization of the milled powders was conducted using X-ray diffraction, and phase transformations as a function of composition were analyzed. Thermal analysis confirmed structural changes occurred in the mechanically alloyed powders. The evolution of the phase transformations with composition is reported for each composition. The results showed that after high energy ball milling for 7 h, the solid solubility between Co and Cr could be evidently extended, despite the low solid solubility at the equilibrium conditions of this system. Additionally, the micrographs of the milled powders showed that increasing composition of chromium changes the shape and size of the particles while simultaneously reducing their agglomeration; this effect is possibly attributed to the brittleness of elemental chrome.

Micromachined Dense Palladium Electrodes for Thin-film Solid Acid Fuel Cells

NARCIS (Netherlands)

Unnikrishnan, S.

2009-01-01

This thesis paves the way towards the microfabrication of a solid acid electrolyte based fuel cell (µSAFC), which has a membrane electrode assembly (MEA) consisting of a thin-film of water soluble electrolyte encapsulated between two dense palladium electrode membranes. This project work

Structural Characterization of Febuxostat/l-Pyroglutamic Acid Cocrystal Using Solid-State 13C-NMR and Investigational Study of Its Water Solubility

Directory of Open Access Journals (Sweden)

Ji-Hun An

2017-12-01

Full Text Available Febuxostat (FB is a poorly water-soluble drug that belongs to BCS class II. The drug is employed for the treatment of inflammatory disease arthritis urica (gout, and the free base, FB form-A, is most preferred for drug formulation. In order to achieve a goal of improving the water solubility of FB form-A, this study was carried out using the cocrystallization technique called the liquid-assisted grinding method to produce FB cocrystals. Here, five amino acids containing amine (NH, oxygen (O, and hydroxyl (OH functional groups, and possessing difference of pKa less than 3 with FB, were selected as coformers. Then, solvents including methanol, ethanol, isopropyl alcohol, n-hexane, dichloromethane, and acetone were used for the cocrystal screening. As a result, a cocrystal was obtained when acetone and l-pyroglutamic acid (PG of 0.5 eq. were employed as solvent and coformer, respectively. The ratio of 2:1, which is the ratio of FB to PG within FB-PG cocrystal, was predicted by means of solid-state CP/MAS 13C-NMR, solution-state NMR (1H, 13C, and 2D and FT-IR. Moreover, Powder X-ray Diffraction (PXRD, Differential Scanning Calorimetry (DSC, and Thermogravimetric Analysis (TGA were used to investigate the characteristics of FB-PG cocrystal. In addition, comparative solubility tests between FB-PG cocrystal and FB form-A were conducted in deionized water and under simulated gastrointestinal pH (1.2, 4, and 6.8 conditions. The result revealed that FB-PG cocrystal has a solubility of four-fold higher than FB form-A in deionized water and two-fold and five-fold greater than FB form-A at simulated gastrointestinal pH 1.2 and pH 4, respectively. Besides, solubilities of FB-PG cocrystal and FB form-A at pH 6.8 were similar to the results measured in deionized water. Therefore, it is postulated that FB-PG cocrystal has a potential overcoming the limitations related to the low aqueous solubility of FB form-A. Accordingly, FB-PG cocrystal is suggested as an

Nondestructive quantification of the soluble-solids content and the available acidity of apples by Fourier-transform near-infrared spectroscopy

Science.gov (United States)

Ying, Yibin; Liu, Yande; Tao, Yang

2005-09-01

This research evaluated the feasibility of using Fourier-transform near-infrared (FT-NIR) spectroscopy to quantify the soluble-solids content (SSC) and the available acidity (VA) in intact apples. Partial least-squares calibration models, obtained from several preprocessing techniques (smoothing, derivative, etc.) in several wave-number ranges were compared. The best models were obtained with the high coefficient determination (r) 0.940 for the SSC and a moderate r of 0.801 for the VA, root-mean-square errors of prediction of 0.272% and 0.053%, and root-mean-square errors of calibration of 0.261% and 0.046%, respectively. The results indicate that the FT-NIR spectroscopy yields good predictions of the SSC and also showed the feasibility of using it to predict the VA of apples.

Nondestructive quantification of the soluble-solids content and the available acidity of apples by Fourier-transform near-infrared spectroscopy

International Nuclear Information System (INIS)

Ying Yibin; Liu Yande; Tao Yang

2005-01-01

This research evaluated the feasibility of using Fourier-transform near-infrared (FT-NIR) spectroscopy to quantify the soluble-solids content (SSC) and the available acidity (VA) in intact apples. Partial least-squares calibration models, obtained from several preprocessing techniques (smoothing, derivative, etc.) in several wave-number ranges were compared. The best models were obtained with the high coefficient determination (r 2 ) 0.940 for the SSC and a moderate r 2 of 0.801 for the VA, root-mean-square errors of prediction of 0.272% and 0.053%, and root-mean-square errors of calibration of 0.261% and 0.046%, respectively. The results indicate that the FT-NIR spectroscopy yields good predictions of the SSC and also showed the feasibility of using it to predict the VA of apples

Production of furfural from xylose, water-insoluble hemicelluloses and water-soluble fraction of corncob via a tin-loaded montmorillonite solid acid catalyst.

Science.gov (United States)

Li, Huiling; Ren, Junli; Zhong, Linjie; Sun, Runcang; Liang, Lei

2015-01-01

The conversion of xylose, water-insoluble hemicelluloses (WIH) and water-soluble fraction (WSF) of corncob to furfural was performed using montmorillonite with tin ions (Sn-MMT) containing double acid sites as a solid acid catalyst. The co-existence of Lewis acids and Brønsted acids in Sn-MMT was shown to improve the furfural yield and selectivity. 76.79% furfural yield and 82.45% furfural selectivity were obtained from xylose using Sn-MMT as a catalyst in a biphasic system with 2-s-butylphenol (SBP) as the organic extracting layer and dimethyl sulfoxide (DMSO) as the co-solvent in contact with an aqueous phase saturated with NaCl (SBP/NaCl-DMSO) at 180°C for 30min. Furthermore, Sn-MMT also demonstrated the excellent catalytic performance in the conversion of pentose-rich materials of corncob and 39.56% and 54.15% furfural yields can be directly obtained from WIH and WSF in the SBP/NaCl-DMSO system, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of solid dispersion systems of dapivirine to enhance its solubility.

Science.gov (United States)

Gorajana, Adinarayana; Ying, Chan Chiew; Shuang, Yeen; Fong, Pooi; Tan, Zhi; Gupta, Jyoti; Talekar, Meghna; Sharma, Manisha; Garg, Sanjay

2013-06-01

Dapivirine, formerly known as TMC 120, is a poorly-water soluble anti-HIV drug, currently being developed as a vaginal microbicide. The clinical use of this drug has been limited due to its poor solubility. The aim of this study was to design solid dispersion systems of Dapivirine to improve its solubility. Solid dispersions were prepared by solvent and fusion methods. Dapivirine release from the solid dispersion system was determined by conducting in-vitro dissolution studies. The physicochemical characteristics of the drug and its formulation were studied using Differential Scanning Calorimetry (DSC), powder X-ray Diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). A significant improvement in drug dissolution rate was observed with the solid dispersion systems. XRD, SEM and DSC results indicated the transformation of pure Dapivirine which exists in crystalline form into an amorphous form in selected solid dispersion formulations. FTIR and HPLC analysis confirmed the absence of drug-excipient interactions. Solid dispersion systems can be used to improve the dissolution rate of Dapivirine. This improvement could be attributed to the reduction or absence of drug crystallinity, existence of drug particles in an amorphous form and improved wettability of the drug.

Solubilities of boric acid in heavy water

International Nuclear Information System (INIS)

Nakai, Shigetsugu; Aoi, Hideki; Hayashi, Ken-ichi; Katoh, Taizo; Watanabe, Takashi.

1988-01-01

A gravimetric analysis using meta-boric acid (HBO 2 or DBO 2 ) as a weighing form has been developed for solubility measurement. The method gave satisfactory results in preliminary measurement of solubilities of boric acid in light water. By using this method, the solubilities of 10 B enriched D 3 BO 3 in heavy water were measured. The results are as follows; 2.67 (7deg C), 3.52 (15deg C), 5.70 (30deg C), 8.87 (50deg C) and 12.92 (70deg C) w/o, respectively. These values are about 10% lower than those in light water. Thermodynamical consideration based on the data shows that boric acid is the water structure breaker. (author)

The solubilities of benzene polycarboxylic acids in water

International Nuclear Information System (INIS)

Apelblat, Alexander; Manzurola, Emanuel; Abo Balal, Nazmia

2006-01-01

The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

Binary and ternary solid-liquid phase equilibrium for the systems formed by succinic acid, urea and diethylene glycol: Determination and modelling

International Nuclear Information System (INIS)

Li, Yanxun; Li, Congcong; Han, Shuo; Zhao, Hongkun

2017-01-01

Highlights: • Solubility of succinic acid in diethylene glycol was determined. • Solubility of succinic acid + urea + diethylene glycol was determined. • Three ternary phase diagrams were constructed for the ternary system. • The ternary phase diagrams were correlated using NRTL model. - Abstract: In this work, the solid-liquid phase equilibrium for binary system of succinic acid + diethylene glycol at the temperatures ranging from (298.15 to 333.15) K and ternary system of (succinic acid + urea + diethylene glycol) at 298.15 K, 313.15 K and 333.15 K was built by using the isothermal saturation method under atmospheric pressure (101.2 kPa), and the solubilities were determined by a high-performance liquid chromatography. The solid-phases formed in the ternary system of ((succinic acid + urea + diethylene glycol)) were confirmed by Schreinemaker’s method of wet residue, which corresponded to urea, succinic acid, and adduct 2:1 urea-succinic acid (mole ratio). Three isothermal phase diagrams for the ternary system were constructed based on the measured mutual solubility. Each isothermal phase diagram included six crystallization fields, three invariant curves, two invariant points and two co-saturated points. The crystalline region of adduct 2:1 urea-succinic acid is larger than those of the other two solids. The solubility of succinic acid in diethylene glycol was correlated with the modified Apelblat equation, λh equation and NRTL model; and the mutual solubility of the ternary ((succinic acid + urea + diethylene glycol)) system was correlated and calculated by the NRTL model. The interaction parameters’ values of succinic acid-urea were acquired. The value of RMSD was 7.11 × 10 −3 for the ternary system. The calculation results had good agreement with the experiment values. Furthermore, the densities of equilibrium liquid phase were acquired. The phase diagrams and the thermodynamic model of the ternary system could provide the basis for design of

Studies on dissolution enhancement and mathematical modeling of drug release of a poorly water-soluble drug using water-soluble carriers.

Science.gov (United States)

Ahuja, Naveen; Katare, Om Prakash; Singh, Bhupinder

2007-01-01

Role of various water-soluble carriers was studied for dissolution enhancement of a poorly soluble model drug, rofecoxib, using solid dispersion approach. Diverse carriers viz. polyethylene glycols (PEG 4000 and 6000), polyglycolized fatty acid ester (Gelucire 44/14), polyvinylpyrollidone K25 (PVP), poloxamers (Lutrol F127 and F68), polyols (mannitol, sorbitol), organic acid (citric acid) and hydrotropes (urea, nicotinamide) were investigated for the purpose. Phase-solubility studies revealed AL type of curves for each carrier, indicating linear increase in drug solubility with carrier concentration. The sign and magnitude of the thermodynamic parameter, Gibbs free energy of transfer, indicated spontaneity of solubilization process. All the solid dispersions showed dissolution improvement vis-à-vis pure drug to varying degrees, with citric acid, PVP and poloxamers as the most promising carriers. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer-Peppas model and the drug release kinetics primarily as Fickian diffusion. Solid state characterization of the drug-poloxamer binary system using XRD, FTIR, DSC and SEM techniques revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement in dissolution rate.

Fundamental aspects of solid dispersion technology for poorly soluble drugs

Directory of Open Access Journals (Sweden)

Yanbin Huang

2014-02-01

Full Text Available The solid dispersion has become an established solubilization technology for poorly water soluble drugs. Since a solid dispersion is basically a drug–polymer two-component system, the drug–polymer interaction is the determining factor in its design and performance. In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

Enthalpy-entropy compensation for the solubility of drugs in solvent mixtures: paracetamol, acetanilide, and nalidixic acid in dioxane-water.

Science.gov (United States)

Bustamante, P; Romero, S; Pena, A; Escalera, B; Reillo, A

1998-12-01

In earlier work, a nonlinear enthalpy-entropy compensation was observed for the solubility of phenacetin in dioxane-water mixtures. This effect had not been earlier reported for the solubility of drugs in solvent mixtures. To gain insight into the compensation effect, the behavior of the apparent thermodynamic magnitudes for the solubility of paracetamol, acetanilide, and nalidixic acid is studied in this work. The solubility of these drugs was measured at several temperatures in dioxane-water mixtures. DSC analysis was performed on the original powders and on the solid phases after equilibration with the solvent mixture. The thermal properties of the solid phases did not show significant changes. The three drugs display a solubility maximum against the cosolvent ratio. The solubility peaks of acetanilide and nalidixic acid shift to a more polar region at the higher temperatures. Nonlinear van't Hoff plots were observed for nalidixic acid whereas acetanilide and paracetamol show linear behavior at the temperature range studied. The apparent enthalpies of solution are endothermic going through a maximum at 50% dioxane. Two different mechanisms, entropy and enthalpy, are suggested to be the driving forces that increase the solubility of the three drugs. Solubility is entropy controlled at the water-rich region (0-50% dioxane) and enthalpy controlled at the dioxane-rich region (50-100% dioxane). The enthalpy-entropy compensation analysis also suggests that two different mechanisms, dependent on cosolvent ratio, are involved in the solubility enhancement of the three drugs. The plots of deltaH versus deltaG are nonlinear, and the slope changes from positive to negative above 50% dioxane. The compensation effect for the thermodynamic magnitudes of transfer from water to the aqueous mixtures can be described by a common empirical nonlinear relationship, with the exception of paracetamol, which follows a separate linear relationship at dioxane ratios above 50%. The

Development of a solid self-microemulsifying drug delivery system (SMEDDS) for solubility enhancement of naproxen.

Science.gov (United States)

Čerpnjak, Katja; Zvonar, Alenka; Vrečer, Franc; Gašperlin, Mirjana

2015-01-01

Comparative evaluation of liquid and solid self-microemulsifying drug delivery systems (SMEDDS) as promising approaches for solubility enhancement. The aim of this work was to develop, characterize, and evaluate a solid SMEDDS prepared via spray-drying of a liquid SMEDDS based on Gelucire® 44/14 to improve the solubility and dissolution rate of naproxen. Various oils and co-surfactants in combination with Gelucire® 44/14 were evaluated during excipient selection study, solubility testing, and construction of (pseudo)ternary diagrams. The selected system was further evaluated for naproxen solubility, self-microemulsification ability, and in vitro dissolution of naproxen. In addition, its transformation into a solid SMEDDS by spray-drying using maltodextrin as a solid carrier was performed. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to evaluate the physical characteristics of the solid SMEDDS obtained. The selected formulation of SMEDDS was comprised of Miglyol 812®, Peceol™, Gelucire® 44/14, and Solutol® HS 15. The liquid and solid SMEDDS formed a microemulsion after dilution with comparable average droplet size and exhibited uniform droplet size distribution. In the solid SMEDDS, liquid SMEDDS was adsorbed onto the surface of maltodextrin and formed smooth granular particles with the encapsulated drug predominantly in a dissolved state and partially in an amorphous state. Overall, incorporation of naproxen in SMEDDS, either liquid or solid, resulted in improved solubility and dissolution rate compared to pure naproxen. This study indicates that a liquid and solid SMEDDS is a strategy for solubility enhancement in the future development of orally delivered dosage forms.

Impact of the counterion on the solubility and physicochemical properties of salts of carboxylic acid drugs.

Science.gov (United States)

David, S E; Timmins, P; Conway, B R

2012-01-01

Salt formation is a widely used approach to improve the physicochemical and solid state properties of an active pharmaceutical ingredient. In order to better understand the relationships between the active drug, the selected counterion and the resultant salt form, crystalline salts were formed using four different carboxylic acid drugs and a closely related series of amine counterions. Thirty-six related crystalline salts were prepared, characterized and the relationship between solubility and dissolution behaviour and other properties of the salt and the counterion studied. Salts of four model acid drugs, gemfibrozil, flurbiprofen, ibuprofen and etodolac were prepared using the counterions butylamine, hexylamine, octylamine, benzylamine, cyclohexylamine, tert-butylamine, 2-amino-2-methylpropan-1-ol, 2-amino-2-methylpropan-1,3-diol and tris(hydroxymethyl)aminomethane. Salt formation was confirmed, the salts were characterized and their corresponding solubilities determined and rationalized with respect to the counterions' properties. The properties of the salt highly dependent on the nature of the counterion and, although there is considerable variation, some general conclusion can be drawn. For the alkyl amines series, increasing chain length leads to a reduction in solubility across all the acidic drugs studied and a reduction in melting point, thus contradicting simplistic relationships between solubility and melting point. Small, compact counterions consistently produce crystalline salts with high melting point accompanied with a modest improvement in solubility and the nature of hydrogen bonding between the ions has a major impact on the solubility.

Method for Predicting Solubilities of Solids in Mixed Solvents

DEFF Research Database (Denmark)

Ellegaard, Martin Dela; Abildskov, Jens; O'Connell, J. P.

2009-01-01

A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximatio...

Solid acid catalysis from fundamentals to applications

CERN Document Server

Hattori, Hideshi

2014-01-01

IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

pH-metric solubility. 3. Dissolution titration template method for solubility determination.

Science.gov (United States)

Avdeef, A; Berger, C M

2001-12-01

The main objective of this study was to develop an effective potentiometric saturation titration protocol for determining the aqueous intrinsic solubility and the solubility-pH profile of ionizable molecules, with the specific aim of overcoming incomplete dissolution conditions, while attempting to shorten the data collection time. A modern theory of dissolution kinetics (an extension of the Noyes-Whitney approach) was applied to acid-base titration experiments. A thermodynamic method was developed, based on a three-component model, to calculate interfacial, diffusion-layer, and bulk-water reactant concentrations in saturated solutions of ionizable compounds perturbed by additions of acid/base titrant, leading to partial dissolution of the solid material. Ten commercial drugs (cimetidine, diltiazem hydrochloride, enalapril maleate, metoprolol tartrate, nadolol, propoxyphene hydrochloride, quinine hydrochloride, terfenadine, trovafloxacin mesylate, and benzoic acid) were chosen to illustrate the new titration methodology. It was shown that the new method is about 10 times faster in determining equilibrium solubility constants, compared to the traditional saturation shake-flask methods.

Solubilities of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures

International Nuclear Information System (INIS)

Wang, Hui; Wang, Qinbo; Xiong, Zhenhua; Chen, Chuxiong; Shen, Binwei

2015-01-01

Highlights: • Solubilities of benzoic acid in (benzyl alcohol + benzaldehyde) mixtures were measured at 1 atm. • The experimental temperature ranges at (298.35 to 355.65) K. • Effects of benzyl alcohol mass concentration at (0.00 to 1.00) on the solubilities of benzoic acid were studied. • The experimental data were correlated with NRTL model. • Thermodynamic functions of dissolution of benzoic acid in (benzyl alcohol + benzaldehyde) mixtures were discussed. - Abstract: The solubility of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures was measured at temperature from (298.35 to 355.65) K and atmospheric pressure. The measured solubility increases with the increasing temperature at constant solvent composition. The effects of mass fraction benzaldehyde in the solvent mixtures at (0.0 to 1.00) on the solubility were studied. The measured solubility decreases with the increasing mass fraction of benzaldehyde. The experimental results were correlated with the non-random two-liquid (NRTL) equations, and good agreement between the correlated and the experimental values was obtained. Thermodynamic functions for the solution of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures were calculated with the van’t Hoff plot. The apparent dissolution Gibbs free energy change was also calculated

Poly(aspartic acid) with adjustable pH-dependent solubility.

Science.gov (United States)

Németh, Csaba; Gyarmati, Benjámin; Abdullin, Timur; László, Krisztina; Szilágyi, András

2017-02-01

Poly(aspartic acid) (PASP) derivatives with adjustable pH-dependent solubility were synthesized and characterized to establish the relationship between their structure and solubility in order to predict their applicability as a basic material for enteric coatings. Polysuccinimide, the precursor of PASP, was modified with short chain alkylamines, and the residual succinimide rings were subsequently opened to prepare the corresponding PASP derivatives. Study of the effect of the type and concentration of the side groups on the pH-dependent solubility of PASP showed that solubility can be adjusted by proper selection of the chemical structure. The Henderson-Hasselbalch (HH) and the extended HH equations were used to describe the pH-dependent solubility of the polymers quantitatively. The estimate provided by the HH equation is poor, but an accurate description of the pH-dependent solubility can be found with the extended HH equation. The dissolution rate of a polymer film prepared from a selected PASP derivative was determined by fluorescence marking. The film dissolved rapidly when the pH was increased above its pK a . Cellular viability tests show that PASP derivatives are non-toxic to a human cell line. These polymers are thus of great interest as starting materials for enteric coatings. Poly(amino acid) type biocompatible polymers were synthesized for future use as pharmaceutical film coatings. To this end, we tailored the pH-dependent solubility of poly(aspartic acid) (PASP). It was found that both the solubility and the pK a values of the modified PASP depended strongly on composition. Fluorescent marking was used to characterize the dissolution of a chosen PASP derivative. In acidic media only a negligible amount of the polymer dissolved, but dissolution was very fast and complete at the pH values that prevail in the small intestine. As a consequence, enteric coatings based on such PASP derivatives may be used for drug delivery in the gastrointestinal tract

Separation of oils from solids

International Nuclear Information System (INIS)

Van Slyke, D.C.

1992-01-01

This patent describes a method for cleaning oil-contaminated particulate solids. It comprises: contacting contaminated solids with a non-aqueous liquid composition comprising a carboxylic acid; then contacting the solids with an aqueous wash containing a reagent for converting the carboxylic acid to a water-soluble carboxylate salt; and removing an aqueous phase containing carboxylate salt and entrained oil

Studies on Dissolution Enhancement of Prednisolone, a Poorly Water-Soluble Drug by Solid Dispersion Technique

Directory of Open Access Journals (Sweden)

Parvin Zakeri-Milani

2011-06-01

Full Text Available Introduction: Prednisolone is a class II substance according to the Biopharmaceutics Classification System. It is a poorly water soluble agent. The aim of the present study was to improve dissolution rate of a poorly water-soluble drug, prednisolone, by a solid dispersion technique. Methods: Solid dispersion of prednisolone was prepared with PEG 6000 or different carbohydrates such as lactose and dextrin with various ratios of the drug to carrier i.e., 1:10, 1:20 and 1:40. Solid dispersions were prepared by coevaporation method. The evaluation of the properties of the dispersions was performed using dissolution studies, Fourier-transform infrared spectroscopy and x-ray powder diffractometery. Results: The results indicated that lactose is suitable carriers to enhance the in vitro dissolution rate of prednisolone. The data from the x-ray diffraction showed that the drug was still detectable in its solid state in all solid dispersions except solid dispersions prepared by dextrin as carrier. The results from infrared spectroscopy showed no well-defined drug–carrier interactions for coevaporates. Conclusion: Solid dispersion of a poorly water-soluble drug, prednisolone may alleviate the problems of delayed and inconsistent rate of dissolution of the drug.

Preparation and investigation of mefenamic acid - polyethylene glycol - sucrose ester solid dispersions.

Science.gov (United States)

Fülöp, Ibolya; Gyéresi, Árpád; Kiss, Lóránd; Deli, Mária A; Croitoru, Mircea Dumitru; Szabó-Révész, Piroska; Aigner, Zoltán

2015-12-01

Mefenamic acid (MA) is a widely used non-steroidal antiinflammatory (NSAID) drug. The adverse effects typical of NSAIDs are also present in the case of MA, partly due to its low water solubility. The aim of this study was to increase the water solubility of MA in order to influence its absorption and bioavailability. Solid dispersions of MA were prepared by the melting method using polyethylene glycol 6000 and different types (laurate, D-1216; palmitate, P-1670; stearate, S-1670) and amounts of sucrose esters as carriers. The X-ray diffraction results show that MA crystals were not present in the products. Dissolution tests carried out in artificial intestinal juice showed that the product containing 10 % D-1216 increased water solubility about 3 times. The apparent permeability coefficient of MA across human Caco-2 intestinal epithelial cell layers was high and, despite the difference in solubility, there was no further increase in drug penetration in the presence of the applied additives.

SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

Directory of Open Access Journals (Sweden)

F. J. Justel

2015-09-01

Full Text Available AbstractIn Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different temperatures (293.15 to 318.15 K, and its effect on physical properties (density, viscosity, and solubility. Knowledge of these properties and solubility data are useful in the leaching process and in the design of copper sulfate pentahydrate crystallization plants from the leaching process using seawater by means of the addition of sulfuric acid.

Structure-property relationships in halogenbenzoic acids: Thermodynamics of sublimation, fusion, vaporization and solubility.

Science.gov (United States)

Zherikova, Kseniya V; Svetlov, Aleksey A; Kuratieva, Natalia V; Verevkin, Sergey P

2016-10-01

Temperature dependences of vapor pressures for 2-, 3-, and 4-bromobenzoic acid, as well as for five isomeric bromo-methylbenzoic acids were studied by the transpiration method. Melting temperatures and enthalpies of fusion for all isomeric bromo-methylbenzoic acids and 4-bromobenzoic acid were measured with a DSC. The molar enthalpies of sublimation and vaporization were derived. These data together with results available in the literature were collected and checked for internal consistency using a group-additivity procedure and results from X-ray structural diffraction studies. Specific (hydrogen bonding) interactions in the liquid and in the crystal phase of halogenbenzoic acids were quantified based on experimental values of vaporization and sublimation enthalpies. Structure-property correlations of solubilities of halogenobenzoic acids with sublimation pressures and sublimation enthalpies were developed and solubilities of bromo-benzoic acids were estimated. These new results resolve much of the ambiguity in the available thermochemical and solubility data on bromobenzoic acids. The approach based on structure property correlations can be applied for the assessment of water solubility of sparingly soluble drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physicochemical characterization of tacrolimus-loaded solid dispersion with sodium carboxylmethyl cellulose and sodium lauryl sulfate.

Science.gov (United States)

Park, Young-Joon; Ryu, Dong-Sung; Li, Dong Xun; Quan, Qi Zhe; Oh, Dong Hoon; Kim, Jong Oh; Seo, Youn Gee; Lee, Young-Im; Yong, Chul Soon; Woo, Jong Soo; Choi, Han-Gon

2009-06-01

To develop a novel tacrolimus-loaded solid dispersion with improved solubility, various solid dispersions were prepared with various ratios of water, sodium lauryl sulfate, citric acid and carboxylmethylcellulose-Na using spray drying technique. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy, differential scanning calorimetery and powder X-ray diffraction. Furthermore, their solubility and dissolution were evaluated compared to drug powder. The solid dispersion at the tacrolimus/CMC-Na/sodium lauryl sulfate/citric acid ratio of 3/24/3/0.2 significantly improved the drug solubility and dissolution compared to powder. The scanning electron microscopy result suggested that carriers might be attached to the surface of drug in this solid dispersion. Unlike traditional solid dispersion systems, the crystal form of drug in this solid dispersion could not be converted to amorphous form, which was confirmed by the analysis of DSC and powder X-ray diffraction. Thus, the solid dispersion system with water, sodium lauryl sulfate, citric acid and CMC-Na should be a potential candidate for delivering a poorly water-soluble tacrolimus with enhanced solubility and no convertible crystalline.

Probing the mechanisms of drug release from amorphous solid dispersions in medium-soluble and medium-insoluble carriers.

Science.gov (United States)

Sun, Dajun D; Lee, Ping I

2015-08-10

The objective of the current study is to mechanistically differentiate the dissolution and supersaturation behaviors of amorphous drugs from amorphous solid dispersions (ASDs) based on medium-soluble versus medium-insoluble carriers under nonsink dissolution conditions through a direct head-to-head comparison. ASDs of indomethacin (IND) were prepared in several polymers which exhibit different solubility behaviors in acidic (pH1.2) and basic (pH7.4) dissolution media. The selected polymers range from water-soluble (e.g., PVP and Soluplus) and water-insoluble (e.g., ethylcellulose and Eudragit RL PO) to those only soluble in an acidic or basic dissolution medium (e.g., Eudragit E100, Eudragit L100, and HPMCAS). At 20wt.% drug loading, DSC and powder XRD analysis confirmed that the majority of incorporated IND was present in an amorphous state. Our nonsink dissolution results confirm that whether the carrier matrix is medium soluble determines the release mechanism of amorphous drugs from ASD systems which has a direct impact on the rate of supersaturation generation, thus in turn affecting the evolution of supersaturation in amorphous systems. For example, under nonsink dissolution conditions, the release of amorphous IND from medium-soluble carriers is governed by a dissolution-controlled mechanism leading to an initial surge of supersaturation followed by a sharp decline in drug concentration due to rapid nucleation and crystallization. In contrast, the dissolution of IND ASD from medium-insoluble carriers is more gradual as drug release is regulated by a diffusion-controlled mechanism by which drug supersaturation is built up gradually and sustained over an extended period of time without any apparent decline. Since several tested carrier polymers can be switched from soluble to insoluble by simply changing the pH of the dissolution medium, the results obtained here provide unequivocal evidence of the proposed transition of kinetic solubility profiles from the

Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

International Nuclear Information System (INIS)

Aronu, Ugochukwu E.; Hartono, Ardi; Svendsen, Hallvard F.

2012-01-01

Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N 2 O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N 2 O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N 2 O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N 2 O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

Solubility Limits of Dibutyl Phosphoric Acid in Uranium Solutions at SRS

International Nuclear Information System (INIS)

Thompson, M.C.; Pierce, R.A.; Ray, R.J.

1998-06-01

The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with DBP which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. SRTC tests have shown that U-DBP solids will precipitate at concentrations potentially attainable during storage of enriched uranium solutions. Evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if DBP concentration in the resulting solution exceeds 110 ppm at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. The most important variables of interest for present plant operations are HNO 3 and DBP concentrations. Temperature is also an important variable controlling precipitation. The data obtained in these tests can be used to set operating and safety limits for the plant. It is recommended that the data for 0 degrees C with 0.5 M HNO 3 be used for setting the limits. The limit would be 80 mg/L which is 3 standard deviations below the average of 86 observed in the tests. The data shows that super-saturation can occur when the DBP concentration is as much as 50 percent above the solubility limit. However, super-saturation cannot be relied on for maintaining nuclear criticality safety. The analytical method for determining DBP concentration in U solutions was improved so that analyses for a solution are accurate to within 10 percent. However, the overall uncertainty of results for periodic samples of the existing EUS solutions was only reduced slightly. Thus, sampling appears to be the largest portion

Crosslinked hydrogels?a promising class of insoluble solid molecular dispersion carriers for enhancing the delivery of poorly soluble drugs

OpenAIRE

Sun, Dajun D.; Lee, Ping I.

2014-01-01

Water-insoluble materials containing amorphous solid dispersions (ASD) are an emerging category of drug carriers which can effectively improve dissolution kinetics and kinetic solubility of poorly soluble drugs. ASDs based on water-insoluble crosslinked hydrogels have unique features in contrast to those based on conventional water-soluble and water-insoluble carriers. For example, solid molecular dispersions of poorly soluble drugs in poly(2-hydroxyethyl methacrylate) (PHEMA) can maintain a ...

Solubilization of poorly water-soluble drugs using solid dispersions.

Science.gov (United States)

Tran, Thao T-D; Tran, Phuong H-L; Khanh, Tran N; Van, Toi V; Lee, Beom-Jin

2013-08-01

Many new drugs have been discovered in pharmaceutical industry and exposed their surprised potential therapeutic effects. Unfortunately, these drugs possess low absorption and bioavailability since their solubility limitation in water. Solid dispersion (SD) is the current technique gaining so many attractions from scientists due to its effect on improving solubility and dissolution rate of poorly water-soluble drugs. A number of patents including the most recent inventions have been undertaken in this review to address various respects of this strategy in solubilization of poorly watersoluble drugs including type of carriers, preparation methods and view of technologies used to detect SD properties and mechanisms with the aim to accomplish a SD not only effective on enhanced bioavailability but also overcome difficulties associated with stability and production. Future prospects are as well discussed with an only hope that many developments and researches in this field will be successfully reached and contributed to commercial use for treatment as much as possible.

Robust model of fresh jujube soluble solids content with near ...

African Journals Online (AJOL)

A robust partial least square (PLS) calibration model with high accuracy and stability was established for the measurement of soluble solids content (SSC) of fresh jujube using near-infrared (NIR) spectroscopy technique. Fresh jujube samples were collected in different areas of Taigu and Taiyuan cities, central China in ...

Encapsulation of solid dispersion in solid lipid particles for dissolution enhancement of poorly water-soluble drug.

Science.gov (United States)

Tran, Khanh Thi My; Vo, Toi Van; Tran, Phuong Ha-Lien; Lee, Beom-Jin; Duan, Wei; Tran, Thao Truong-Dinh

2017-06-05

The aim of this research was to engineer solid dispersion lipid particles (SD-SLs) in which a solid dispersion (SD) was encapsulated to form the core of solid lipid particles (SLs), thereby achieving an efficient enhancement in the dissolution of a poorly water-soluble drug. Ultrasonication was introduced into the process to obtain micro/nanoscale SLs. The mechanism of dissolution enhancement was investigated by analysing the crystalline structure, molecular interactions, and particle size of the formulations. The drug release from the SD-SLs was significantly greater than that from the SD or SLs alone. This enhancement in drug release was dependent on the preparation method and the drug-to-polymer ratio of the SD. With an appropriate amount of polymer in the SD, the solidification method had the potential to alter the drug crystallinity to an amorphous state, resulting in particle uniformity and molecular interactions in the SD-SLs. The proposed system provides a new strategy for enhancing the dissolution rate of poorly water-soluble drugs and further improving their bioavailability. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A Soluble, Folded Protein without Charged Amino Acid Residues

DEFF Research Database (Denmark)

Højgaard, Casper; Kofoed, Christian; Espersen, Roall

2016-01-01

Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable...... side chains can maintain solubility, stability, and function. As a model, we used a cellulose-binding domain from Cellulomonas fimi, which, among proteins of more than 100 amino acids, presently is the least charged in the Protein Data Bank, with a total of only four titratable residues. We find...

Eutectic, monotectic and immiscibility systems of nimesulide with water-soluble carriers: phase equilibria, solid-state characterisation and in-vivo/pharmacodynamic evaluation.

Science.gov (United States)

Abdelkader, Hamdy; Abdallah, Ossama Y; Salem, Hesham; Alani, Adam W G; Alany, Raid G

2014-10-01

The solid-state interactions of fused mixtures nimesulide (ND) with polyethylene glycol (PEG) 4000, urea or mannitol were studied through constructing thaw-melt phase equilibrium diagrams. The solid-state characteristics were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Various types of interactions were identified such as the formation of a eutectic system of ND-PEG 4000, monotectic system of ND-urea and complete solid immiscibility of ND with mannitol. The effects of carrier concentrations on the equilibrium solubility and in-vitro dissolution characteristics were studied. Linear increases (R(2)  > 0.99) in the aqueous solubility of ND in various concentrations of PEG 4000 and urea were obtained, whereas mannitol did not exhibit any effect on the solubility of ND. Similar trends were obtained with the dissolution efficiency of the fused mixtures of ND with PEG 4000 and urea compared with the corresponding physical mixtures and untreated drug. The analgesic effects of untreated ND and the selected formulations were investigated by evaluating the drug's ability to inhibit the acetic acid-induced writhing response. The analgesic effect of ND in a eutectic mixture with PEG 4000 and a monotectic mixture with urea was potentiated by 3.2 and 2.7-fold respectively compared with the untreated drug. © 2014 Royal Pharmaceutical Society.

Drug Solubility in Fatty Acids as a Formulation Design Approach for Lipid-Based Formulations: A Technical Note.

Science.gov (United States)

Lee, Yung-Chi; Dalton, Chad; Regler, Brian; Harris, David

2018-06-06

Lipid-based drug delivery systems have been intensively investigated as a means of delivering poorly water-soluble drugs. Upon ingestion, the lipases in the gastrointestinal tract digest lipid ingredients, mainly triglycerides, within the formulation into monoglycerides and fatty acids. While numerous studies have addressed the solubility of drugs in triglycerides, comparatively few publications have addressed the solubility of drugs in fatty acids, which are the end product of digestion and responsible for the solubility of drug within mixed micelles. The objective of this investigation was to explore the solubility of a poorly water-soluble drug in fatty acids and raise the awareness of the importance of drug solubility in fatty acids. The model API (active pharmaceutical ingredient), a weak acid, is considered a BCS II compound with an aqueous solubility of 0.02 μg/mL and predicted partition coefficient >7. The solubility of API ranged from 120 mg/mL to over 1 g/mL in fatty acids with chain lengths across the range C18 to C6. Hydrogen bonding was found to be the main driver of the solubilization of API in fatty acids. The solubility of API was significantly reduced by water uptake in caprylic acid but not in oleic acid. This report demonstrates that solubility data generated in fatty acids can provide an indication of the solubility of the drug after lipid digestion. This report also highlights the importance of measuring the solubility of drugs in fatty acids in the course of lipid formulation development.

Solubility of the Proteinogenic α-Amino Acids in Water, Ethanol, and Ethanol–Water Mixtures

Science.gov (United States)

2018-01-01

The addition of organic solvents to α-amino acids in aqueous solution could be an effective method in crystallization. We reviewed the available data on the solubility of α-amino acids in water, water–ethanol mixtures, and ethanol at 298.15 K and 0.1 MPa. The solubility of l-alanine, l-proline, l-arginine, l-cysteine, and l-lysine in water and ethanol mixtures and the solubility of l-alanine, l-proline, l-arginine, l-cysteine, l-lysine, l-asparagine, l-glutamine, l-histidine, and l-leucine in pure ethanol systems were measured and are published here for the first time. The impact on the solubility of amino acids that can convert in solution, l-glutamic acid and l-cysteine, was studied. At lower concentrations, only the ninhydrin method and the ultraperfomance liquid chromatography (UPLC) method yield reliable results. In the case of α-amino acids that convert in solution, only the UPLC method was able to discern between the different α-amino acids and yields reliable results. Our results demonstrate that α-amino acids with similar physical structures have similar changes in solubility in mixed water/ethanol mixtures. The solubility of l-tryptophan increased at moderate ethanol concentrations. PMID:29545650

A facile physical approach to make chitosan soluble in acid-free water.

Science.gov (United States)

Fu, Yinghao; Xiao, Congming

2017-10-01

We changed the situation that chitosan was only dissolved in diluted acid through mild physical treatment. In viewing of the usual methods to modify chitosan are chemical ones, we established the approach by using a water-soluble chitosan derivative as the model polymer. Its water-solubility was modulated via changing the concentration of solution and varying the precipitants. Such a physical method was adopted to treat chitiosan. One gram chitosan was dissolved in a mixture of 100mL 10% acetic acid and 50mL methanol, and then precipitated from a precipitant consisted of 10mL ethanol and 90mL acetate ester. The treated chitosan became soluble in acid-free water completely, and its solubility was 8.02mg/mL. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural Characterization of Febuxostat/l-Pyroglutamic Acid Cocrystal Using Solid-State 13C-NMR and Investigational Study of Its Water Solubility

OpenAIRE

Ji-Hun An; Changjin Lim; Hyung Chul Ryu; Jae Sun Kim; Hyuk Min Kim; Alice Nguvoko Kiyonga; Minho Park; Young-Ger Suh; Gyu Hwan Park; Kiwon Jung

2017-01-01

Febuxostat (FB) is a poorly water-soluble drug that belongs to BCS class II. The drug is employed for the treatment of inflammatory disease arthritis urica (gout), and the free base, FB form-A, is most preferred for drug formulation. In order to achieve a goal of improving the water solubility of FB form-A, this study was carried out using the cocrystallization technique called the liquid-assisted grinding method to produce FB cocrystals. Here, five amino acids containing amine (NH), oxygen (...

Solubility and dissolution performances of spray-dried solid dispersion of Efavirenz in Soluplus.

Science.gov (United States)

Lavra, Zênia Maria Maciel; Pereira de Santana, Davi; Ré, Maria Inês

2017-01-01

Efavirenz (EFV), a first-line anti-HIV drug largely used as part of antiretroviral therapies, is practically insoluble in water and belongs to BCS class II (low solubility/high permeability). The aim of this study was to improve the solubility and dissolution performances of EFV by formulating an amorphous solid dispersion of the drug in polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus ® ) using spray-drying technique. To this purpose, spray-dried dispersions of EFV in Soluplus ® at different mass ratios (1:1.25, 1:7, 1:10) were prepared and characterized using particle size measurements, SEM, XRD, DSC, FTIR and Raman microscopy mapping. Solubility and dissolution were determined in different media. Stability was studied at accelerated conditions (40 °C/75% RH) and ambient conditions for 12 months. DSC and XRD analyses confirmed the EFV amorphous state. FTIR spectroscopy analyses revealed possible drug-polymer molecular interaction. Solubility and dissolution rate of EFV was enhanced remarkably in the developed spray-dried solid dispersions, as a function of the polymer concentration. Spray-drying was concluded to be a proper technique to formulate a physically stable dispersion of amorphous EFV in Soluplus ® , when protected from moisture.

Preparation and investigation of mefenamic acid – polyethylene glycol – sucrose ester solid dispersions

Directory of Open Access Journals (Sweden)

Fülöp Ibolya

2015-12-01

Full Text Available Mefenamic acid (MA is a widely used non-steroidal antiinflammatory (NSAID drug. The adverse effects typical of NSAIDs are also present in the case of MA, partly due to its low water solubility. The aim of this study was to increase the water solubility of MA in order to influence its absorption and bioavailability. Solid dispersions of MA were prepared by the melting method using polyethylene glycol 6000 and different types (laurate, D-1216; palmitate, P-1670; stearate, S-1670 and amounts of sucrose esters as carriers. The X-ray diffraction results show that MA crystals were not present in the products. Dissolution tests carried out in artificial intestinal juice showed that the product containing 10 % D-1216 increased water solubility about 3 times. The apparent permeability coefficient of MA across human Caco-2 intestinal epithelial cell layers was high and, despite the difference in solubility, there was no further increase in drug penetration in the presence of the applied additives.

Levels of acid-soluble polyphosphate in growing cultures of Saccharomyces cerevisiae.

OpenAIRE

Solimene, R; Guerrini, A M; Donini, P

1980-01-01

Short-chain acid-soluble polyphosphates were extracted from growing cultures of Saccharomyces cerevisiae, and the changes in the levels of these compounds were determined. The production of acid-soluble polyphosphates correlated with the mitochondrial activities since it occurred in two bursts in respiration-competent yeast cells and in only one burst in respiration-deficient yeast cells. The possible role of these compounds is discussed.

Design, optimization and evaluation of glipizide solid self-nanoemulsifying drug delivery for enhanced solubility and dissolution.

Science.gov (United States)

Dash, Rajendra Narayan; Mohammed, Habibuddin; Humaira, Touseef; Ramesh, Devi

2015-10-01

A solid self-nanoemulsifying drug-delivery system (solid SNEDDS) has been explored to improve the solubility and dissolution profile of glipizide. SNEDDS preconcentrate was systematically optimized using a circumscribed central composite design by varying Captex 355 (Oil), Solutol HS15 (Surfactant) and Imwitor 988 (Co-surfactant). The optimized SNEDDS preconcentrate consisted of Captex 355 (30% w/w), Solutol HS15 (45% w/w) and Imwitor 988 (25% w/w). The saturation solubility (SS) of glipizide in optimized SNEDDS preconcentrate was found to be 45.12 ± 1.36 mg/ml, indicating an improvement (1367 times) of glipizide solubility as compared to its aqueous solubility (0.033 ± 0.0021 mg/ml). At 90% SS, glipizide was loaded to the optimized SNEDDS. In-vitro dilution of liquid SNEDDS resulted in a nanoemulsion with a mean droplet size of 29.4 nm. TEM studies of diluted liquid SNEDDS confirmed the uniform shape and size of the globules. The liquid SNEDDS was adsorbed onto calcium carbonate and talc to form solid SNEDDS. PXRD, DSC, and SEM results indicated that, the presence of glipizide as an amorphous and as a molecular dispersion state within solid SNEDDS. Glipizide dissolution improved significantly (p < 0.001) from the solid SNEDDS (∼100% in 15 min) as compared to the pure drug (18.37%) and commercial product (65.82) respectively.

Carbon-based strong solid acid for cornstarch hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Nata, Iryanti Fatyasari, E-mail: yanti_tkunlam@yahoo.com [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Irawan, Chairul; Mardina, Primata [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Lee, Cheng-Kang, E-mail: cklee@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Rd. Sec.4, Taipei 106, Taiwan (China)

2015-10-15

Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

Carbon-based strong solid acid for cornstarch hydrolysis

International Nuclear Information System (INIS)

Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

2015-01-01

Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO 3 H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO 3 H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use

Drug-Drug Multicomponent Solid Forms: Cocrystal, Coamorphous and Eutectic of Three Poorly Soluble Antihypertensive Drugs Using Mechanochemical Approach.

Science.gov (United States)

Haneef, Jamshed; Chadha, Renu

2017-08-01

The present study deals with the application of mechanochemical approach for the preparation of drug-drug multicomponent solid forms of three poorly soluble antihypertensive drugs (telmisartan, irbesartan and hydrochlorothiazide) using atenolol as a coformer. The resultant solid forms comprise of cocrystal (telmisartan-atenolol), coamorphous (irbesartan-atenolol) and eutectic (hydrochlorothiazide-atenolol). The study emphasizes that solid-state transformation of drug molecules into new forms is a result of the change in structural patterns, diminishing of dimers and creating new facile hydrogen bonding network based on structural resemblance. The propensity for heteromeric or homomeric interaction between two different drugs resulted into diverse solid forms (cocrystal/coamorphous/eutectics) and become one of the interesting aspects of this research work. Evaluation of these solid forms revealed an increase in solubility and dissolution leading to better antihypertensive activity in deoxycorticosterone acetate (DOCA) salt-induced animal model. Thus, development of these drug-drug multicomponent solid forms is a promising and viable approach to addressing the issue of poor solubility and could be of considerable interest in dual drug therapy for the treatment of hypertension.

Thermodynamic functions for solubility of 3-nitro-o-toluic acid in nine organic solvents from T = (283.15 to 318.15) K and apparent thermodynamic properties of solutions

International Nuclear Information System (INIS)

Li, Xinbao; Wang, Mingju; Du, Cunbin; Cong, Yang; Zhao, Hongkun

2017-01-01

Highlights: • Solubilities of 3-nitro-o-toluic acid in nine organic solvents were determined. • The solubilities were correlated by using four thermodynamic models. • The mixing properties of solution were computed based on Wilson model. - Abstract: Separation of 3-nitro-o-toluic acid from its isomeric mixtures has essential significance in industry. In this work, by using isothermal saturation method, the solid-liquid equilibrium for 3-nitro-o-toluic acid in nine organic solvents (acetonitrile, methanol, ethanol, n-propanol, isopropanol, ethyl acetate, acetone, 1,4-dioxane and 2-butanone) were obtained experimentally within a temperature range from (283.15 to 318.15) K under atmosphere pressure of 101.2 kPa, and the solubility values of 3-nitro-o-toluic acid in these solvents were determined by a high-performance liquid chromatography. Within the studied temperature range, the mole fraction solubility of 3-nitro-o-toluic acid in selected organic solvents increased with increasing temperature. Except for ethyl acetate, the descending order of the mole fraction solubility values were as follow: 1,4-dioxane > acetone > 2-butanone > methanol > ethanol > isopropanol > n-propanol > acetonitrile. The solubility values determined for 3-nitro-o-toluic acid in the selected solvents were correlated and back calculated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of RAD and RMSD obtained with the four models were 0.67% and 4.02 × 10 −4 , respectively. In general, the four thermodynamic models were all acceptable for describing the solubility behaviour of 3-nitro-o-toluic acid in these solvents. In addition, the apparent mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy were calculated. The acquired solubility data and thermodynamic studies would be very important in optimizing the separation process of 3-nitro-o-toluic acid from

The effect of treating plum tree with Rovral (iprodion and Euparen (dichlofluanid on the content of soluble solids in fruit

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Halina Borecka

2013-12-01

Full Text Available The concentration of soluble solids in plum fruit varied and depended on the cultivar, year, and fungicide treatment. Plums from trees treated with Rovral (iprodion contained in some case the lowest level of soluble solids, higher or equal levels were found in those sprayed with Euparen (dichlofluanid, and the highest concentration of soluble solids was in fruits from untreated trees. Explanation of this phenomenon is possible by looking for changes in photosynthesis of treated and untreated leaves. Fungicide treatment of some plum cultivars, particularly with Rovral, decreased the photosynthesis of the leaves.

Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt.

Science.gov (United States)

Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R

2013-12-02

Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.

The amorphous solid dispersion of the poorly soluble ABT-102 forms nano/microparticulate structures in aqueous medium: impact on solubility

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Frank KJ

2012-11-01

Full Text Available Kerstin J Frank,1,3 Ulrich Westedt,2 Karin M Rosenblatt,2 Peter Hölig,2 Jörg Rosenberg,2 Markus Mägerlein,2 Gert Fricker,3 Martin Brandl11Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark; 2Abbott GmbH and Co. KG, Ludwigshafen, Germany; 3Department of Pharmaceutical Technology, University of Heidelberg, Heidelberg, GermanyAbstract: Amorphous solid dispersions (ASDs are a promising formulation approach for poorly soluble active pharmaceutical ingredients (APIs, because they ideally enhance both dissolution rate and solubility. However, the mechanism behind this is not understood in detail. In the present study, we investigated the supramolecular and the nano/microparticulate structures that emerge spontaneously upon dispersion of an ASD in aqueous medium and elucidated their influence on solubility. The ASD, prepared by hot melt extrusion, contained the poorly soluble ABT-102 (solubility in buffer, 0.05 µg/mL, a hydrophilic polymer, and three surfactants. The apparent solubility of ABT-102 from the ASD-formulation was enhanced up to 200 times in comparison to crystalline ABT-102. At the same time, the molecular solubility, as assessed by inverse equilibrium dialysis, was enhanced two times. Asymmetrical flow field-flow fractionation in combination with a multiangle light-scattering detector, an ultraviolet detector, and a refractometer enabled us to separate and identify the various supramolecular assemblies that were present in the aqueous dispersions of the API-free ASD (placebo and of binary/ternary blends of the ingredients. Thus, the supramolecular assemblies with a molar mass between 20,000 and 90,000 could be assigned to the polyvinylpyrrolidone/vinyl acetate 64, while two other kinds of assemblies were assigned to different surfactant assemblies (micelles. The amount of ABT-102 remaining associated with each of the assemblies upon fractionation was quantified offline with high

The performance of a soluble lead-acid flow battery and its comparison to a static lead-acid battery

International Nuclear Information System (INIS)

Zhang, C.P.; Sharkh, S.M.; Li, X.; Walsh, F.C.; Zhang, C.N.; Jiang, J.C.

2011-01-01

Highlights: → We compared the electrochemical characteristics of two types of the batteries. → SLAFB shows as good performance as SLAB under the same current density. → The cycle life of two batteries is strongly influenced by the depth of discharge. → The cycle life of SLAFB can be extended by treatment with hydrogen peroxide. - Abstract: The electrochemistry of static lead-acid and soluble lead-acid flow batteries is summarised and the differences between the two batteries are highlighted. A general comparison of the performance of an unoptimised soluble lead-acid flow laboratory cell and a commercial lead-acid battery during charge and discharge is reported. The influence of the depth of discharge on cycle life for both batteries is also considered. The flow battery was found to have a better charge efficiency than the static one, but the cells were found to have comparable energy efficiencies. The self-discharge characteristics of the soluble lead-acid battery were also measured and compared to reported values for a commercial static battery. Some self-discharge of the soluble lead-acid flow battery is observed during prolonged periods on open-circuit but the battery could recover its normal performance after a single charge-discharge cycle.

Solubility of gallic acid in liquid mixtures of (ethanol + water) from (293.15 to 318.15) K

International Nuclear Information System (INIS)

Noubigh, Adel; Jeribi, Chokri; Mgaidi, Arbi; Abderrabba, Manef

2012-01-01

Graphical abstract: Solubility of gallic acid vs the mole fraction of ethanol (0.0 to 1) on a solute-free basis in ethanol + water at different temperatures/K. □, 293.15; Δ, 298.15; ◊, 303.15; line calculated by equation. Highlights: ► Solubilities of gallic acid in binary mixtures were determined over the temperatures range (293.15 to 318.15) K. ► The gallic acid solubility in mixed solvents presents a maximum-solubility effect. ► Two empirical equations were proposed to correlate the solubility Data. ► The thermodynamic properties were determined. - Abstract: The solubility of gallic acid in (water + ethanol) binary solvents was determined from (293.15 to 318.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. It was found that gallic acid solubility in (water + ethanol) mixed solvents presents a maximum-solubility effect. Two empirical equations were proposed to correlate the solubility data. The calculated solubilities show good agreement with the experimental data within the studied temperature range. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the gallic acid such as Gibbs energy (Δ sol G°), molar enthalpy of dissolution (Δ sol H°), and molar entropy of dissolution (Δ sol S°) were calculated.

Crystal-Structure Contribution to the Solid Solubility in Transition Metal Alloys

DEFF Research Database (Denmark)

Ruban, Andrei; Skriver, Hans Lomholt; Nørskov, Jens Kehlet

1998-01-01

The solution energies of 4d metals in other 4d metals as well as the bcc-hcp structural energy differences in random 4d alloys are calculated by density functional theory. It is shown that the crystal structure of the host plays a crucial role in the solid solubility. A local virtual bond...

Solid dispersions in oncology: a solution to solubility-limited oral drug absorption

NARCIS (Netherlands)

Sawicki, Emilia

2017-01-01

This thesis discusses the formulation method solid dispersion and how it works to resolve solubility-limited absorption of orally dosed anticancer drugs. Dissolution in water is essential for drug absorption because only dissolved drug molecules are absorbed. The problem is that half of the arsenal

Crosslinked hydrogels—a promising class of insoluble solid molecular dispersion carriers for enhancing the delivery of poorly soluble drugs

Directory of Open Access Journals (Sweden)

Dajun D. Sun

2014-02-01

Full Text Available Water-insoluble materials containing amorphous solid dispersions (ASD are an emerging category of drug carriers which can effectively improve dissolution kinetics and kinetic solubility of poorly soluble drugs. ASDs based on water-insoluble crosslinked hydrogels have unique features in contrast to those based on conventional water-soluble and water-insoluble carriers. For example, solid molecular dispersions of poorly soluble drugs in poly(2-hydroxyethyl methacrylate (PHEMA can maintain a high level of supersaturation over a prolonged period of time via a feedback-controlled diffusion mechanism thus avoiding the initial surge of supersaturation followed by a sharp decline in drug concentration typically encountered with ASDs based on water-soluble polymers. The creation of both immediate- and controlled-release ASD dosage forms is also achievable with the PHEMA based hydrogels. So far, ASD systems based on glassy PHEMA have been shown to be very effective in retarding precipitation of amorphous drugs in the solid state to achieve a robust physical stability. This review summarizes recent research efforts in investigating the potential of developing crosslinked PHEMA hydrogels as a promising alternative to conventional water-soluble ASD carriers, and a related finding that the rate of supersaturation generation does affect the kinetic solubility profiles implications to hydrogel based ASDs.

Crosslinked hydrogels-a promising class of insoluble solid molecular dispersion carriers for enhancing the delivery of poorly soluble drugs.

Science.gov (United States)

Sun, Dajun D; Lee, Ping I

2014-02-01

Water-insoluble materials containing amorphous solid dispersions (ASD) are an emerging category of drug carriers which can effectively improve dissolution kinetics and kinetic solubility of poorly soluble drugs. ASDs based on water-insoluble crosslinked hydrogels have unique features in contrast to those based on conventional water-soluble and water-insoluble carriers. For example, solid molecular dispersions of poorly soluble drugs in poly(2-hydroxyethyl methacrylate) (PHEMA) can maintain a high level of supersaturation over a prolonged period of time via a feedback-controlled diffusion mechanism thus avoiding the initial surge of supersaturation followed by a sharp decline in drug concentration typically encountered with ASDs based on water-soluble polymers. The creation of both immediate- and controlled-release ASD dosage forms is also achievable with the PHEMA based hydrogels. So far, ASD systems based on glassy PHEMA have been shown to be very effective in retarding precipitation of amorphous drugs in the solid state to achieve a robust physical stability. This review summarizes recent research efforts in investigating the potential of developing crosslinked PHEMA hydrogels as a promising alternative to conventional water-soluble ASD carriers, and a related finding that the rate of supersaturation generation does affect the kinetic solubility profiles implications to hydrogel based ASDs.

Solid dispersions enhance solubility, dissolution, and permeability of thalidomide.

Science.gov (United States)

Barea, Silvana A; Mattos, Cristiane B; Cruz, Ariadne C C; Chaves, Vitor C; Pereira, Rafael N; Simões, Claudia M O; Kratz, Jadel M; Koester, Letícia S

2017-03-01

Thalidomide (THD) is a BCS class II drug with renewed and growing therapeutic applicability. Along with the low aqueous solubility, additional poor biopharmaceutical properties of the drug, i.e. chemical instability, high crystallinity, and polymorphism, lead to a slow and variable oral absorption. In this view, we developed solid dispersions (SDs) containing THD dispersed in different self-emulsifying carriers aiming at an enhanced absorption profile for the drug. THD was dispersed in lauroyl macrogol-32 glycerides (Gelucire ® 44/14) and α-tocopherol polyethylene glycol succinate (Kolliphor ® TPGS), in the presence or absence of the precipitation inhibitor polyvinylpyrrolidone K30 (PVP K30), by means of the solvent method. Physicochemical analysis revealed the formation of semicrystalline SDs. X-ray diffraction and infrared spectroscopy analyses suggest that the remaining crystalline fraction of the drug in the SDs did not undergo polymorphic transition. The impact of the solubility-enhancing formulations on the THD biopharmaceutical properties was evaluated by several in vitro techniques. The developed SDs were able to increase the apparent solubility of the drug (up to 2-3x the equilibrium solubility) for a least 4 h. Dissolution experiments (paddle method, 75 rpm) in different pHs showed that around 80% of drug dissolved after 120 min (versus 40% of pure crystalline drug). Additionally, we demonstrated the enhanced solubility obtained via SDs could be translated into increased flux in a parallel artificial membrane permeability assay (PAMPA). In summary, the results demonstrate that SDs could be considered an interesting and unexplored strategy to improve the biopharmaceutical properties of THD, since SDs of this important drug have yet to be reported.

Revealing facts behind spray dried solid dispersion technology used for solubility enhancement

Science.gov (United States)

Patel, Bhavesh B.; Patel, Jayvadan K.; Chakraborty, Subhashis; Shukla, Dali

2013-01-01

Poor solubility and bioavailability of an existing or newly synthesized drug always pose challenge in the development of efficient pharmaceutical formulation. Numerous technologies can be used to improve the solubility and among them amorphous solid dispersion based spray drying technology can be successfully useful for development of product from lab scale to commercial scale with a wide range of powder characteristics. Current review deals with the importance of spray drying technology in drug delivery, basically for solubility and bioavailability enhancement. Role of additives, selection of polymer, effect of process and formulation parameters, scale up optimization, and IVIVC have been covered to gain the interest of readers about the technology. Design of experiment (DoE) to optimize the spray drying process has been covered in the review. A lot more research work is required to evaluate spray drying as a technology for screening the right polymer for solid dispersion, especially to overcome the issue related to drug re-crystallization and to achieve a stable product both in vitro and in vivo. Based on the recent FDA recommendation, the need of the hour is also to adopt Quality by Design approach in the manufacturing process to carefully optimize the spray drying technology for its smooth transfer from lab scale to commercial scale. PMID:27134535

Green synthesis of 3,4-dihydropyrimidinones using nano Fe3O4@meglumine sulfonic acid as a new efficient solid acid catalyst under microwave irradiation

Directory of Open Access Journals (Sweden)

Leila Moradi

2018-01-01

Full Text Available Design, synthesis and characterization of nano Fe3O4@meglumine sulfonic acid as a new solid acid catalyst for the simple and green one pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H-ones/thiones was studied. New solid acid catalyst was prepared through a clean and simple protocol and characterized using FTIR, VSM, TGA, SEM, elemental analysis (CHN and XRD techniques. Heterogenization of homogeneous catalyst as a green approach is a useful method for enhancing the efficiency of catalyst. Presented study was a new method for attachment of homogeneous highly soluble catalyst (meglumine sulfate to the magnetite nanoparticle surfaces for preparing a heterogeneous and effective catalyst. Obtained heterogeneous and reusable solid acid catalyst has high performance in the synthesis of Biginelli compounds. The reaction was performed under microwave irradiation as a rapid and green condition. Easy work up as well as excellent yield (90–98% of products in short reaction times (40–200 s and reusable catalyst are the main advantages of presented procedure. Reaction products were characterized in details using physical and chemical techniques such as melting point, 1H NMR, 13C NMR and FTIR.

Continuous synthesis of Oleyl Oleate in supercritical carbon oxide using solid p-Toluenesulfonic Acid as catalyst

International Nuclear Information System (INIS)

Ghaziaskar, H.; Ikushima, Y.

2000-01-01

Supercritical carbon dioxide (Sc-CO 2 ) was used as solvent to synthesize oleyl oleate as an analog of Jojoba oil from oleic acid and oleyl alcohol with high conversion (100%) of the acid into ester in a short time of 100 min. Utilizing a low cost solid catalyst, p-toluenesulfonic acid monohydrate , the esterification reaction was performed, without any prior preparation step, in a flow mode, at a pressure of 147 bar and a temperature of 60 d eg C. This method seems industrially suitable for the production of oleyl oleate. The solubility of a mixture of oleyl alcohol and oleic acid in Sc-CO 2 were also measured to calculate the alcohol to acid ratio and the esterification yield

The acid solubility test of clay mineral under microwave

International Nuclear Information System (INIS)

Zheng Ying; Niu Yuqing; Wu Peisheng; Niu Xuejun

2001-01-01

The acid solubility test of Al 3+ in clay from some uranium ores under microwave is introduced. The result shows that the concentration of Al 3+ in solution and the acid consumption increase rapidly under microwave comparing with normal leaching condition. It is infeasible to adopt microwave slacking method for intensively leaching uranium from uranium ore containing more clay

CO2 Solubilities in Amide-based Brφnsted Acidic Ionic Liquids

International Nuclear Information System (INIS)

Palgunadi, Jelliarko; Im, Jin Kyu; Kang, Je Eun; Kim, Hoon Sik; Cheong, Min Serk

2010-01-01

A distinguished class of hydrophobic ionic liquids bearing a Brφnsted acidic character derived from amide-like compounds were prepared by a neutralization reaction of N,N-diethylformamide, N,N-dibutylformamide, 1-formylpiperidine, and ε-caprolactam with trifluoroacetic acid and physical absorptions of CO 2 in these ionic liquids were demonstrated and evaluated. CO 2 solubilities in these ionic liquids were influenced by the molecular structure of the cation and were apparently increased with the molar volume. Comparison based on a volume unit reveals that CO 2 solubilities in these liquids are relatively higher than those in imidazolium-based ionic liquids. Henry's coefficients calculated from low-pressure solubility tests at 313 to 333 K were used to derive the thermodynamics quantities. Enthalpy and entropy of solvation may share equal contributions in solubility

Chasing equilibrium: measuring the intrinsic solubility of weak acids and bases.

Science.gov (United States)

Stuart, Martin; Box, Karl

2005-02-15

A novel procedure is described for rapid (20-80 min) measurement of intrinsic solubility values of organic acids, bases, and ampholytes. In this procedure, a quantity of substance was first dissolved at a pH where it exists predominantly in its ionized form, and then a precipitate of the neutral (un-ionized) species was formed by changing the pH. Subsequently, the rate of change of pH due to precipitation or dissolution was monitored and strong acid and base titrant were added to adjust the pH to discover its equilibrium conditions, and the intrinsic solubility of the neutral form of the compound could then be determined. The procedure was applied to a variety of monoprotic and diprotic pharmaceutical compounds. The results were highly repeatable and had a good correlation to available published values. Data collected during the procedure provided good diagnostic information. Kinetic solubility data were also collected but provided a poor guide to the intrinsic solubility.

Thermodynamic Solubility Profile of Carbamazepine-Cinnamic Acid Cocrystal at Different pH.

Science.gov (United States)

Keramatnia, Fatemeh; Shayanfar, Ali; Jouyban, Abolghasem

2015-08-01

Pharmaceutical cocrystal formation is a direct way to dramatically influence physicochemical properties of drug substances, especially their solubility and dissolution rate. Because of their instability in the solution, thermodynamic solubility of cocrystals could not be determined in the common way like other compounds; therefore, the thermodynamic solubility is calculated through concentration of their components in the eutectic point. The objective of this study is to investigate the effect of an ionizable coformer in cocrystal with a nonionizable drug at different pH. Carbamazepine (CBZ), a nonionizable drug with cinnamic acid (CIN), which is an acidic coformer, was selected to prepare CBZ-CIN cocrystal and its thermodynamic solubility was studied in pH range 2-7. Instead of HPLC that is a costly and time-consuming method, a chemometric-based approach, net analyte signal standard addition method, was selected for simultaneous determination of CBZ and CIN in solution. The result showed that, as pH increases, CIN ionization leads to change in CBZ-CIN cocrystal solubility and stability in solution. In addition, the results of this study indicated that there is no significant difference between intrinsic solubility of CBZ and cocrystal despite the higher ideal solubility of cocrystal. This verifies that ideal solubility is not good parameter to predict cocrystal solubility. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

An estimation of influence of humic acid and organic matter originated from bentonite on samarium solubility

International Nuclear Information System (INIS)

Kanaji, Mariko; Sato, Haruo; Sasahira, Akira

1999-10-01

Organic acids in groundwater are considered to form complexes and increase the solubility of radionuclides released from vitrified waste in a high-level radioactive waste (HLW) repository. To investigate whether the solubility of samarium (Sm) is influenced by organic substances, we measured Sm solubility in the presence of different organic substances and compared those values with results from thermodynamic predictions. Humic acid (Aldrich) is commercially available and soluble organic matter originated from bentonite were used as organic substances in this study. Consequently, the solubility of Sm showed a tendency to apparently increase with increasing the concentration of humic acid, but in the presence of carbonate, thermodynamic predictions suggested that the dominant species are carbonate complexes and that the effect of organic substances are less than that of carbonate. Based on total organic carbon (TOC), the increase of Sm solubility measured with humic acid (Aldrich) was more significant than that in the case with soluble organic matter originated from bentonite. Since bentonite is presumed to include also simple organic matters of which stability constant for forming complexes is low, the effect of soluble organic matter originated from bentonite on the solubility of Sm is considered to be less effective than that of humic acid (Aldrich). Experimental values were compared with model prediction, proposed by Kim, based on data measured in a low pH region. Tentatively we calculated the increase in Sm solubility assuming complexation with humic acid. Trial calculations were carried out on the premise that the complexation reaction of metal ion with humic acid is based on neutralization process by 1-1 complexation. In this process, it was assumed that one metal ion coordinates with one unit of complexation sites which number of proton exchange sites is equal to ionic charge. Consequently, Kim's model indicated that carbonate complexes should be dominant

Ionic liquid-assisted solublization for improved enzymatic esterification of phenolic acids

DEFF Research Database (Denmark)

Yang, Zhiyong; Guo, Zheng; Xu, Xuebing

2012-01-01

in a binary system, which is composed of ionic liquid tOMA•TFA (trioctylmethylammonium Trifluoroacetate) and octanol. Ionic liquid tOMA•TFA has great solubility towards most of phenolic acid. The strategy of increasing the solubility of phenolic in ionic liquid tOMA•TFA was proved to be an efficient way...... for increasing conversion of phenolic acids. The mixture ratio between tOMA•TFA and octanol was varied from 1:4 to 1:16 (v/v), it was found that the highest conversion of dihydrocaffeic acid (DHCA) was achieved when tOMA•TFA and octanol was mixed as 1:12 (v/v). It was also found that conversion of DHCA at 70 o...

Anomalous Solubility Behavior of Several Acidic Drugs

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Alex Avdeef

2014-04-01

Full Text Available The “anomalous solubility behavior at higher pH values” of several acidic drugs originally studied by Higuchi et al. in 1953 [1], but hitherto not fully rationalized, has been re-analyzed using a novel solubility-pH analysis computer program, pDISOL-XTM. The program internally derives implicit solubility equations, given a set of proposed equilibria and constants (iteratively refined by weighted nonlinear regression, and does not require explicit Henderson-Hasselbalch equations. The re-analyzed original barbital, phenobarbital, oxytetracycline, and sulfathiazole solubility-pH data of Higuchi et al. is consistent with the presence of dimers in saturated solutions. In the case of barbital, phenobarbital and sulfathiazole, anionic dimers, reaching peak concentrations near pH 8. However, oxytetracycline indicated a pronounced tendency to form a cationic dimer, peaking near pH 2. Under the conditions of the original study, only barbital indicated a slight tendency to form a salt precipitate at pH > 6.8, with a highly unusual stoichiometry (consistent with a slope of 0.55 in the log S – pH plot: K+ + A2H- + 3HA D KA5H4(s. Thus the “anomaly” in the Higuchi data can be rationalized by invoking specific aggregated species.

Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

African Journals Online (AJOL)

NICO

radiation balance.4,5 Major water-soluble inorganic ions are associated with atmospheric ... molecular weight carboxylic acids in aerosol samples collected from a rural ... include biomass burning, agriculture, livestock and soil dust. Tropical ...

Antimicrobial and Antifungal Effects of Acid and Water-Soluble Chitosan Extracted from Indian Shrimp (Fenneropenaeus indicus Shell

Directory of Open Access Journals (Sweden)

Ali Taheri

2013-06-01

Full Text Available Background & Objective : Currently, efforts are underway to seek new and effective antimicrobial agents, and marine resources are potent candidates for this aim. The following study was conducted to investigate the efficacy of water-soluble and acid-soluble chitosan against some pathogenic organisms.   Materials & Method s: Inhibition zone of different concentrations (5, 7.5, and 10 mg/ml of acid- soluble and water-soluble chitosan were examined for in vitro antibacterial activity against 4 kinds of hospital bacteria and penicillium sp. Results were compared with 4 standard antibiotics: streptomycin, gentamicin, tetracycline, and erythromycin. Furthermore, minimum inhibitory concentration and minimum lethal concentration were determined.   Results: Inhibition activity of acid-soluble chitosan (10% showed the best result (p value < 0.05, whereas water-soluble chitosan exhibited the least antibacterial effects (p value < 0.05. Chitosan demonstrated maximum effect on V. cholera cerotype ogava , and the least effect was seen on E. coli (p value < 0.05. Acid-soluble chitosan had a more potent effect than the standard antibiotics. Also, acid-soluble chitosan (10% and water-soluble chitosan showed maximum inhibitory effects on penicillium sp.   Conclusion: Chitosan showed maximum antibacterial effect against S. aureus, V. cholerae cerotype ogava, and water-soluble chitosan demonstrated good antifungal effects, revealing a statistically significant difference with common antibacterial and antifungal medicines.

Development of novel sibutramine base-loaded solid dispersion with gelatin and HPMC: physicochemical characterization and pharmacokinetics in beagle dogs.

Science.gov (United States)

Lim, Hyun-Tae; Balakrishnan, Prabagar; Oh, Dong Hoon; Joe, Kwan Hyung; Kim, Young Ran; Hwang, Doo Hyung; Lee, Yong-Bok; Yong, Chul Soon; Choi, Han-Gon

2010-09-15

To develop a novel sibutramine base-loaded solid dispersion with enhanced solubility and bioavailability, various solid dispersions were prepared using a spray drying technique with hydrophilic polymers such as gelatin, HPMC and citric acid. Their solubility, thermal characteristics and crystallinity were investigated. The dissolution and pharmacokinetics of the sibutramine base-loaded solid dispersion were then compared with a sibutramine hydrochloride monohydrate-loaded commercial product (Reductil). The solid dispersions prepared with gelatin gave higher drug solubility than those prepared without gelatin, irrespective of the amount of polymer. The sibutramine base-loaded solid dispersions containing hydrophilic polymer and citric acid showed higher drug solubility compared to sibutramine base and sibutramine hydrochloride monohydrate. Among the formulations tested, the solid dispersion composed of sibutramine base/gelatin/HPMC/citric acid at the weight ratio of 1/0.8/0.2/0.5 gave the highest solubility of 5.03+/-0.24 mg/ml. Our DSC and powder X-ray diffraction results showed that the drug was present in an altered amorphous form in this solid dispersion. The difference factor (f(1)) values between solid dispersion and commercial product were 2.82, 6.65 and 6.31 at pH 1.2, 4.0 and 6.8, respectively. Furthermore, they had the similarity factor (f(2)) value of 65.68, 53.43 and 58.97 at pH 1.2, 4.0 and 6.8, respectively. Our results suggested that the solid dispersion and commercial product produced a similar correlation of dissolution profiles at all pH ranges. The AUC, C(max) and T(max) of the parent drug and metabolite I and II from the solid dispersion were not significantly different from those of the commercial product, suggesting that the solid dispersion might be bioequivalent to the commercial product in beagle dogs. Thus, the sibutramine base-loaded solid dispersion prepared with gelatin, HPMC and citric acid is a promising candidate for improving the

Solubility and dissolution enhancement of flurbiprofen by solid dispersion using hydrophilic carriers

Directory of Open Access Journals (Sweden)

Bhaskar Daravath

2018-05-01

Full Text Available ABSTRACT The intent of the current work is to study the effect of polyethylene glycol 8000 and polyethylene glycol 10000 as hydrophilic carriers on dissolution behaviour of flurbiprofen. In the present study, solvent evaporation method was used to prepare flurbiprofen solid dispersions and evaluated for physico-chemical properties, drug-carrier compatibility studies and dissolution behaviour of drug. Solubility studies showed more solubility in higher pH values and formulations SD4 and SD8 were selected to prepare the fast dissolving tablets. FTIR and DSC study showed no interaction and drug was dispersed molecularly in hydrophilic carrier. XRD studies revealed that there was change in the crystallinity of the drug. The results of In vitro studies showed SD8 formulation confer significant improvement (p<0.05 in drug release, Q20 was 99.08±1.35% compared to conventional and marketed tablets (47.31±0.74% and 56.86±1.91%. The mean dissolution time (MDT was reduced to 8.79 min compared to conventional and marketed tablets (25.76 and 22.22 min. indicating faster drug release. The DE (% dissolution efficiency was increased by 2.5 folds (61.63% compared to conventional tablets (23.71%. From the results, it is evident that polyethylene glycol solid dispersions in less carrier ratio may enhance the solubility and there by improve the dissolution rate of flurbiprofen.

Synthesis and properties of amino acid functionalized water-soluble perylene diimides

Energy Technology Data Exchange (ETDEWEB)

Ma, Yongshan; Li, Xuemei; Wei, Xiaofeng; Jiang, Tianyi; Wu, Junsen; Ren, Huixue [Shandong Jianzhu University, Jinan (China)

2015-07-15

We prepared amino acid functionalized water-soluble perylene diimides: N,N'-bi(L-glutamic acid)-perylene-3,4;9,10-dicarboxylic diimide (1), N,N'-bi(L-phenylalanine acid)-perylene-3,4;9,10-dicarboxylic diimide (2), N,N'-bi(Lglutamic amine)-perylene-3,4;9,10-dicarboxylic diimide (3) and N,N'-bi(L-phenylalanine amine)-perylene-3,4;9,10-dicarboxylic diimide (4). The structures of 3 and 4 were confirmed by {sup 1}H NMR, FT-IR and MS. The maximal absorption bands of compound 1 and 2 in concentrated sulfuric acid were red-shifted for about 48 and 74 nm, respectively, compared with that of Perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA). Nearly no fluorescence was observed for compounds 1 and 2 in water, while compounds 3 and 4 were significantly water-soluble and had very high fluorescent quantum. The mechanism of the optical properties change was discussed, and the π-π stacking caused by H{sup +} led to the changes of fluorescence spectrum and absorption spectrum. The calculated molecular orbital energies and the frontier molecular orbital maps of compounds 1-2 based on density function theory (DFT) calculations were reported. Owing to the high water-soluble, the perylene derivatives 3 and 4 were successfully applied as high-performance fluorochromes for living hela cells imaging.

Solubility behaviour of antimony(III) and antimony(V) solids in basic aqueous solutions at 300oC

International Nuclear Information System (INIS)

Lemire, R.J.; Tosello, N.B.; Halliday, J.D.

1999-12-01

The major contributions of the isotopes 122 Sb and 124 Sb to activity transport in a CANDU reactor primary heat transport system (HTS), have been associated with oxygen ingress during reactor shutdown. As part of a program to minimize the release and redeposition of these isotopes, the solubilities of antimony(III) and (V) oxides and salts have been measured in basic solutions at temperatures from 25 to 300 o C. The results provide information on the charge and the stability as a function of temperature of antimony solution species and, hence, a guide to the trends in the temperature dependence of the solubilities of antimony solids. In solutions in which oxidation of antimony(III) to antimony(V) is minimized, the solubility of Sb 2 O 3 increases by about two orders of magnitude between 25 and 200 o C, and then levels out or decreases slightly. At 250 o C, in oxidizing solutions, Sb 2 O 5 ·xH 2 O and simple sodium antimonate(V) were found to be unstable in sodium hydroxide solutions with respect to the solid, Na 2α [H(H 2 O)] 2-2α Sb 2 O 6 , which has a pyrochlore structure. The solubility of this partially protonated sodium antimonate increases from 25 to 200 o C and decreases at temperatures above 250 o C. These solubility changes for the antimony (V) solids reflect changes in the stability of the anionic antimony solution species (SbO 3 - or Sb(OH) 6 - ), even though the compositions of antimony-containing solids in basic oxidizing solutions are strongly dependent on the cations and their aqueous phase concentrations. All solids used in the present experiments would be expected to generate total solution antimony concentrations ≥ 0.00005 mol·dm -3 in any neutral or basic aqueous solutions (assuming no added sodium salts). Therefore, under HTS conditions, precipitation of any antimony oxides or mixed oxides is unlikely. It cannot be ruled out that hydrated Sb 2 O 5 (especially the pyrochlore form) might be less soluble in near-neutral, low

Carbon-based strong solid acid for cornstarch hydrolysis

Science.gov (United States)

Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

2015-10-01

Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

How cocrystals of weakly basic drugs and acidic coformers might modulate solubility and stability.

Science.gov (United States)

Kuminek, G; Rodríguez-Hornedo, N; Siedler, S; Rocha, H V A; Cuffini, S L; Cardoso, S G

2016-04-30

Cocrystals of a weakly basic drug (nevirapine) with acidic coformers are shown to alter the solubility dependence on pH, and to exhibit a pHmax above which a less soluble cocrystal becomes more soluble than the drug. The cocrystal solubility advantage can be dialed up or down by solution pH.

Solubility enhancement of BCS Class II drug by solid phospholipid dispersions: Spray drying versus freeze-drying.

Science.gov (United States)

Fong, Sophia Yui Kau; Ibisogly, Asiye; Bauer-Brandl, Annette

2015-12-30

The poor aqueous solubility of BCS Class II drugs represents a major challenge for oral dosage form development. Using celecoxib (CXB) as model drug, the current study adopted a novel solid phospholipid nanoparticle (SPLN) approach and compared the effect of two commonly used industrial manufacturing methods, spray- and freeze-drying, on the solubility and dissolution enhancement of CXB. CXB was formulated with Phospholipoid E80 (PL) and trehalose at different CXB:PL:trehalose ratios, of which 1:10:16 was the optimal formulation. Spherical amorphous SPLNs with average diameters <1μm were produced by spray-drying; while amorphous 'matrix'-like structures of solid PL dispersion with larger particle sizes were prepared by freeze-drying. Formulations from both methods significantly enhanced the dissolution rates, apparent solubility, and molecularly dissolved concentration of CXB in phosphate buffer (PBS, pH 6.5) and in biorelevant fasted state simulated intestinal fluid (FaSSIF, pH 6.5) (p<0.05). While similar dissolution rates were found, the spray-dried SPLNs had a larger enhancement in apparent solubility (29- to 132-fold) as well as molecular solubility (18-fold) of CXB at equilibrium (p<0.05). The strong capability of the spray-dried SPLNs to attain 'true' supersaturation state makes them a promising approach for bioavailability enhancement of poorly soluble drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

Supercritical Carbon Dioxide-Soluble Ligands for Extracting Actinide Metal Ions from Porous Solids

International Nuclear Information System (INIS)

Dietz, Mark L.

2001-01-01

Numerous types of actinide-bearing waste materials are found throughout the DOE complex. Most of these wastes consist of large volumes of non-hazardous materials contaminated with relatively small quantities of actinide elements. Separation of these wastes into their inert and radioactive components would dramatically reduce the costs of stabilization and disposal. For example, the DOE is responsible for decontaminating concrete within 7000 surplus contaminated buildings. The best technology now available for removing surface contamination from concrete involves removing the surface layer by grit blasting, which produces a large volume of blasting residue containing a small amount of radioactive material. Disposal of this residue is expensive because of its large volume and fine particulate nature. Considerable cost savings would result from separation of the radioactive constituents and stabilization of the concrete dust. Similarly, gas diffusion plants for uranium enrichment contain valuable high-purity nickel in the form of diffusion barriers. Decontamination is complicated by the extremely fine pores in these barriers, which are not readily accessible by most cleaning techniques. A cost-effective method for the removal of radioactive contaminants would release this valuable material for salvage. The objective of this project is to develop novel, substituted diphosphonic acid ligands that can be used for supercritical carbon dioxide extraction of actinide ions from solid wastes. Specifically, selected diphosphonic acids, which are known to form extremely stable complexes with actinides in aqueous and organic solution, are to be rendered carbon dioxide-soluble by the introduction of appropriate alkyl- or silicon-containing substituents. The metal complexation chemistry of these new ligands in SC-CO2 will then be investigated and techniques for their use in actinide extraction from porous solids developed

Solubility of the Proteinogenic α-Amino Acids in Water, Ethanol, and Ethanol-Water Mixtures

NARCIS (Netherlands)

Bowden, Nathan A.; Sanders, Johan P.M.; Bruins, Marieke E.

2018-01-01

The addition of organic solvents to α-amino acids in aqueous solution could be an effective method in crystallization. We reviewed the available data on the solubility of α-amino acids in water, water-ethanol mixtures, and ethanol at 298.15 K and 0.1 MPa. The solubility of l-alanine, l-proline,

A Soluble, Folded Protein without Charged Amino Acid Residues

DEFF Research Database (Denmark)

Højgaard, Casper; Kofoed, Christian; Espersen, Roall

2016-01-01

side chains can maintain solubility, stability, and function. As a model, we used a cellulose-binding domain from Cellulomonas fimi, which, among proteins of more than 100 amino acids, presently is the least charged in the Protein Data Bank, with a total of only four titratable residues. We find......Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable...... that the protein shows a surprising resilience toward extremes of pH, demonstrating stability and function (cellulose binding) in the pH range from 2 to 11. To ask whether the four charged residues present were required for these properties of this protein, we altered them to nontitratable ones. Remarkably...

Simple multipurpose apparatus for solubility measurement of solid solutes in liquids

DEFF Research Database (Denmark)

Malwade, Chandrakant Ramkrishna; Christensen, Lars Porskjær

2016-01-01

students of chemical engineering program at University of Southern Denmark. The exercises included solubility measurement and cooling crystallization of salicylic acid from five different organic solvents and extraction of artemisinin from the leaves of the plant Artemisia annua by using different solvents...

A physiological and genetic approach to the improvement of tomato (Lycopersicon esculentum Mill.) fruit soluble solids

International Nuclear Information System (INIS)

Damon, S.E.

1989-01-01

Physiological processes and the genetic basis determining soluble solids content (SSC) of processing tomato fruit were addressed. Analysis of [ 3 H]-(fructosyl)-sucrose translocation in tomato indicates that phloem unloading in the fruit occurs, at least in part, to the apoplast. Apoplastic sucrose, glucose and fructose concentrations were estimated as 1 to 7, 12 to 49 and 8 to 63 millimolar, respectively in tomato fruit pericarp. Short-term uptake of [ 14 C]sucrose, -glucose and -fructose in tomato pericarp discs showes first order kinetics over the physiologically relevant concentration range. The uptake of [ 14 C]-(glycosyl)-1'fluorosucrose was identical to the rate of [ 14 C] sucrose uptake suggesting sucrose may be taken up directly without prior extracellular hydrolysis. Short-term uptake of all three sugars was insensitive to 10 micromolar carbonyl cyanide m-chlorophenylhydrazone and to 10 micromolar p-chloromercuribenzene sulfonic acid. However, long-term accumulation of glucose was sensitive to carbonyl cyanide m-chlorophenylhydrazone. Sugar uptake across the plasmamembrane does not appear to be energy dependent, suggesting that sugar accumulation in the tomato is driven by subsequent intracellular metabolism and/or active uptake at the tonoplast. Fourteen genomic DNA probes and ten restriction endonucleases were used to identify restriction fragment length polymorphisms (RFLPs) useful in the linkage analysis of quantitative trait loci controlling the expression of SSC in a segregating F 2 population from a cross between L. esculentum (UC204B) and L. cheesmanii f. minor, a wild species with high fruit soluble solids. RFLPs were detected between the DNAs of the two tomato species with all 14 probes

Solubility and phase separation of 4-morpholinepropanesulfonic acid (MOPS), and 3-morpholino-2-hydroxypropanesulfonic acid (MOPSO) in aqueous 1,4-dioxane and ethanol solutions

International Nuclear Information System (INIS)

Taha, Mohamed; Lee, Ming-Jer

2011-01-01

Highlights: → Solubilities of MOPS and MOPSO buffers in aqueous 1,4-dioxane and ethanol solutions. → We found that MOPS-induced phase separation of aqueous solution of 1,4-dioxane. → The phase diagram of (MOPS + water + 1,4-dioxane) system at 298.15 K is documented. → The tie-lines within the two-liquid phase region were also determined at 298.15 K. → The effective excluded volume theory was applied to correlate the binodal LLE data. - Abstract: The buffers 4-morpholinepropanesulfonic acid (MOPS) and 3-morpholino-2-hydroxypropanesulfonic acid (MOPSO) are useful biological zwitterionic buffers within the pH range of 6.5 to 7.9 and 6.2 to 7.6, respectively. The solubilities of these buffers were determined in binary mixtures (1,4-dioxane + water) and (ethanol + water) at T = 298.15 K by using the results of density measurements. It has been observed that MOPS induced liquid-liquid phase splitting for the mixtures of 40% to 90% (w/w) 1,4-dioxane in water. The two-liquid phase formation was visualized with disperse orange 25. The phase equilibrium boundaries, including the regions of one liquid, two liquids, (one liquid + one solid) and (two liquids + one solid), for the (MOPS + water + 1,4-dioxane) system have been determined experimentally at T = 298.15 K. The tie lines of the (liquid + liquid) equilibrium were also measured. The Othmer-Tobias and Bancroft equation were used to evaluate the reliability of the tie-line data. The binodal curve was fitted to an empirical equation and the effective excluded volume (EEV) model. The apparent free energies of transfer (ΔG tr ' ) of MOPS and MOPSO from water to 1,4-dioxane and ethanol solutions have been calculated from the solubility data. These ΔG tr ' values were compared with those of some related biological buffers (TRIS, TAPS, TAPSO, and TABS). Furthermore, we also calculated the contribution of transfer free energies (Δg tr ' ) of -OH group from water to 1,4-dioxane and ethanol solutions.

Hygroscopic properties of internally mixed particles composed of NaCl and water-soluble organic acids.

Science.gov (United States)

Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei; Laskin, Alexander

2014-02-18

Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water-soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy, atomic force microscopy, and X-ray elemental microanalysis. Hygroscopic properties of internally mixed NaCl and organic acid particles were distinctly different from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of sodium malonate and sodium glutarate salts resulted by HCl evaporation from dehydrating particles.

Fatty acids polymorphism and solid-state miscibility

Energy Technology Data Exchange (ETDEWEB)

Gbabode, Gabin [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux I, 33405 Talence (France)], E-mail: ggbabode@ulb.ac.be; Negrier, Philippe; Mondieig, Denise [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux I, 33405 Talence (France); Moreno, Evelyn; Calvet, Teresa; Cuevas-Diarte, Miquel Angel [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, 08028 Barcelona (Spain)

2009-02-05

The pentadecanoic acid-hexadecanoic acid (C{sub 15}H{sub 29}OOH-C{sub 16}H{sub 31}OOH) binary system is dealt with in this article. The polymorphism of 20 mixed materials has been investigated combining calorimetric measurements, isothermal and versus temperature X-ray powder diffraction and also FTIR spectroscopy. In particular, the cell parameters of the stable forms, temperatures and heats of phase changes for the two constituents and a proposal of phase diagram are given in this article. Three solid forms are created by mixing in addition with the four solid forms of the pure components. All these solid forms are stabilized on narrow domains of composition, implying a reduced solid-state miscibility of the pentadecanoic and hexadecanoic acids.

Solubility behaviour of antimony(III) and antimony(V) solids in basic aqueous solutions at 300{sup o}C

Energy Technology Data Exchange (ETDEWEB)

Lemire, R.J.; Tosello, N.B.; Halliday, J.D

1999-12-01

The major contributions of the isotopes {sup 122}Sb and {sup 124}Sb to activity transport in a CANDU reactor primary heat transport system (HTS), have been associated with oxygen ingress during reactor shutdown. As part of a program to minimize the release and redeposition of these isotopes, the solubilities of antimony(III) and (V) oxides and salts have been measured in basic solutions at temperatures from 25 to 300{sup o}C. The results provide information on the charge and the stability as a function of temperature of antimony solution species and, hence, a guide to the trends in the temperature dependence of the solubilities of antimony solids. In solutions in which oxidation of antimony(III) to antimony(V) is minimized, the solubility of Sb{sub 2}O{sub 3} increases by about two orders of magnitude between 25 and 200{sup o}C, and then levels out or decreases slightly. At 250{sup o}C, in oxidizing solutions, Sb{sub 2}O{sub 5}{center_dot}xH{sub 2}O and simple sodium antimonate(V) were found to be unstable in sodium hydroxide solutions with respect to the solid, Na{sub 2{alpha}}[H(H{sub 2}O)]{sub 2-2{alpha}}Sb{sub 2}O{sub 6}, which has a pyrochlore structure. The solubility of this partially protonated sodium antimonate increases from 25 to 200{sup o}C and decreases at temperatures above 250{sup o}C. These solubility changes for the antimony (V) solids reflect changes in the stability of the anionic antimony solution species (SbO{sub 3}{sup -} or Sb(OH){sub 6}{sup -}), even though the compositions of antimony-containing solids in basic oxidizing solutions are strongly dependent on the cations and their aqueous phase concentrations. All solids used in the present experiments would be expected to generate total solution antimony concentrations {>=} 0.00005 mol{center_dot}dm{sup -3} in any neutral or basic aqueous solutions (assuming no added sodium salts). Therefore, under HTS conditions, precipitation of any antimony oxides or mixed oxides is unlikely. It cannot be

Boric acid solubility in the presence of alkali metal nitrides

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Tsekhanskij, R S; Molodkin, A K; Sadetdinov, Sh V [Chuvashskij Gosudarstvennyj Univ., Cheboksary (USSR); Universitet Druzhby Narodov, Moscow (USSR))

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodium, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion. Boric acid is salted out from solutions containing lithium and sodium cations with increase of nitrate ion.

Boric acid solubility in the presence of alkali metal nitrides

International Nuclear Information System (INIS)

Skvortsov, V.G.; Tsekhanskij, R.S.; Molodkin, A.K.; Sadetdinov, Sh.V.

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodiUm, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion Boric acid is salted out form solutions containing lithium and sodium cations with increase of nitrate ion

Preparation and evaluation of azithromycin binary solid dispersions using various polyethylene glycols for the improvement of the drug solubility and dissolution rate

Directory of Open Access Journals (Sweden)

Ehsan Adeli

Full Text Available ABSTRACT Azithromycin is a water-insoluble drug, with a very low bioavailability. In order to increase the solubility and dissolution rate, and consequently increase the bioavailability of poorly-soluble drugs (such as azithromycin, various techniques can be applied. One of such techniques is "solid dispersion". This technique is frequently used to improve the dissolution rate of poorly water-soluble compounds. Owing to its low solubility and dissolution rate, azithromycin does not have a suitable bioavailability. Therefore, the main purpose of this investigation was to increase the solubility and dissolution rate of azithromycin by preparing its solid dispersion, using different Polyethylene glycols (PEG. Preparations of solid dispersions and physical mixtures of azithromycin were made using PEG 4000, 6000, 8000, 12000 and 20000 in various ratios, based on the solvent evaporation method. From the studied drug release profile, it was discovered that the dissolution rate of the physical mixture, as the well as the solid dispersions, were higher than those of the drug alone. There was no chemical incompatibility between the drug and polymer from the observed Infrared (IR spectra. Drug-polymer interactions were also investigated using Differential Scanning Calorimetry (DSC, Powder X-Ray Diffraction (PXRD and Scanning Election Microscopy (SEM. In conclusion, the dissolution rate and solubility of azithromycin were found to improve significantly, using hydrophilic carriers, especially PEG 6000.

Light exposure during storage preserving soluble sugar and l-ascorbic acid content of minimally processed romaine lettuce (Lactuca sativa L.var. longifolia).

Science.gov (United States)

Zhan, Lijuan; Hu, Jinqiang; Ai, Zhilu; Pang, Lingyun; Li, Yu; Zhu, Meiyun

2013-01-01

Minimally processed romaine lettuce (MPRL) leaves were stored in light condition (2500lux) or darkness at 4°C for 7d. Light exposure significantly delayed the degradation of chlorophyll and decrease of glucose, reducing sugar, and sucrose content, and thus preserved more total soluble solid (TSS) content at the end of storage in comparison with darkness. While, it did not influenced starch content that progressively decreased over time. The l-ascorbic acid (AA) accumulated in light-stored leaves, but deteriorated in dark-stored leaves during storage. The dehydroascorbic acid (DHA) increased in all leaves stored in both light and dark condition, of which light condition resulted in less DHA than darkness. In addition, the fresh weight loss and dry matter significantly increased and these increases were accelerated by light exposure. Conclusively, light exposure in applied intensity effectively alleviated MPRL quality deterioration by delaying the decreases of pigments, soluble sugar, TSS content and accumulating AA. Copyright © 2012 Elsevier Ltd. All rights reserved.

The "high solubility" definition of the current FDA Guidance on Biopharmaceutical Classification System may be too strict for acidic drugs.

Science.gov (United States)

Yazdanian, Mehran; Briggs, Katherine; Jankovsky, Corinne; Hawi, Amale

2004-02-01

The purpose of this study was to assess if the definition of high solubility as proposed in the FDA Guidance on Biopharmaceutical Classification System (BCS) is too strict for highly permeable acidic drugs. The solubility and permeability values of 20 (18 acidic and 2 non-acidic) nonsteroidal anti-inflammatory drugs (NSAID) were determined. The NSAIDs were grouped into three different sets having acetic acid, propionic acid, or other acidic moieties such as fenamate, oxicam, and salicylate. Two nonacidic NSAIDs (celecoxib and rofecoxib) were also included for comparison purposes. Equilibrium solubility values were determined at pH 1.2, 5.0, 7.4, and in biorelevant media simulating fed intestinal fluid at pH 5.0. For a select number of acids, we also measured solubility values in media simulating gastric and fasted intestinal fluids. Permeability classification was established relative to that of reference drugs in the Caco-2 cell permeability model. Permeability coefficients for all drugs were measured at concentrations corresponding to the lowest and highest marketed dose strengths dissolved in 250 ml volume, and their potential interaction with cellular efflux pumps was investigated. All NSAIDs with different acidic functional groups were classified as highly permeable based on their Caco-2 cell permeability. Only ketorolac appeared to have a potential for interaction with cellular efflux pumps. Solubility classification was based on comparison of equilibrium solubility at pH 1.2, 5.0. and 7.4 relative to marketed dose strengths in 250 ml. The pKa values for the acidic NSAIDs studied were between 3.5 and 5.1. and, as expected, their solubility increased dramatically at pH 7.4 compared to pH 1.2. Only three NSAIDs, ketorolac, ketoprofen. and acetyl salicylic acid, meet the current criteria for high solubility over the entire pH range. However, with the exception of ibuprofen, oxaprozin, and mefenamic acid, the remaining compounds can be classified as Class I drugs

CCN activation experiments with adipic acid: effect of particle phase and adipic acid coatings on soluble and insoluble particles

Directory of Open Access Journals (Sweden)

S. S. Hings

2008-07-01

Full Text Available Slightly soluble atmospherically relevant organic compounds may influence particle CCN activity and therefore cloud formation. Adipic acid is a frequently employed surrogate for such slightly soluble organic materials. The 11 published experimental studies on the CCN activity of adipic acid particles are not consistent with each other nor do they, in most cases, agree with the Köhler theory. The CCN activity of adipic acid aerosol particles was studied over a significantly wider range of conditions than in any previous single study. The work spans the conditions of the previous studies and also provides alternate methods for producing "wet" (deliquesced solution droplets and dry adipic acid particles without the need to produce them by atomization of aqueous solutions. The experiments suggest that the scatter in the previously published CCN measurements is most likely due to the difficulty of producing uncontaminated adipic acid particles by atomization of solutions and possibly also due to uncertainties in the calibration of the instruments. The CCN activation of the small (d_m<150 nm initially dry particles is subject to a deliquescence barrier, while for the larger particles the activation follows the Köhler curve. Wet adipic acid particles follow the Köhler curve over the full range of particle diameters studied. In addition, the effect of adipic acid coatings on the CCN activity of both soluble and insoluble particles has also been studied. When a water-soluble core is coated by adipic acid, the CCN-hindering effect of particle phase is eliminated. An adipic acid coating on hydrophobic soot yields a CCN active particle. If the soot particle is relatively small (d_core≤102 nm, the CCN activity of the coated particles approaches the deliquescence line of adipic acid, suggesting that the total size of the particle determines CCN activation and the soot core acts as a scaffold.

Enhancement of solubility and bioavailability of ambrisentan by solid dispersion using Daucus carota as a drug carrier: formulation, characterization, in vitro, and in vivo study.

Science.gov (United States)

Deshmane, Subhash; Deshmane, Snehal; Shelke, Santosh; Biyani, Kailash

2018-06-01

Ambrisentan is an US FDA approved drug, it is the second oral endothelin A receptor antagonist known for the treatment of pulmonary arterial hypertension, but its oral administration is limited due to its poor water solubility. Hence, the objective of the investigation was focused on enhancement of solubility and bioavailability of ambrisentan by solid dispersion technique using natural Daucus carota extract as drug carrier. Drug carrier was evaluated for solubility, swelling index, viscosity, angle of repose, hydration capacity, and acute toxicity test (LD 50 ). Ambrisentan was studied for the saturation solubility, phase solubility, and Gibbs free energy change. Compatibility of drug and the natural carrier was confirmed by DSC, FTIR, and XRD. Solid dispersions were evaluated for drug content, solubility, morphology, in vitro, and in vivo study. Screening of the natural carrier showed the desirable properties like water solubility, less swelling index, less viscosity, and acute toxicity study revealed no any clinical symptoms of toxicity. Drug and carrier interaction study confirmed the compatibility to consider its use in the formulation. Formed particles were found to be spherical with smooth surface. In vitro studies revealed higher drug release from the solid dispersion than that of the physical mixture. Bioavailability study confirms the increased absorption and bioavailability by oral administration of solid dispersion. Hence, it can be concluded that the natural Daucus carota extract can be the better alternative source for the preparation of solid dispersion and/or other dosage forms for improving solubility and bioavailability.

Comparative transcriptome analysis reveals key genes potentially related to soluble sugar and organic acid accumulation in watermelon

Science.gov (United States)

Gao, Lei; Zhao, Shengjie; Lu, Xuqiang; He, Nan; Zhu, Hongju; Dou, Junling

2018-01-01

Soluble sugars and organic acids are important components of fruit flavor and have a strong impact on the overall organoleptic quality of watermelon (Citrullus lanatus) fruit. Several studies have analyzed the expression levels of the genes related to soluble sugar accumulation and the dynamic changes in their content during watermelon fruit development and ripening. Nevertheless, to date, there have been no reports on the organic acid content in watermelon or the genes regulating their synthesis. In this study, the soluble sugars and organic acids in watermelon were measured and a comparative transcriptome analysis was performed to identify the key genes involved in the accumulation of these substances during fruit development and ripening. The watermelon cultivar ‘203Z’ and its near-isogenic line (NIL) ‘SW’ (in the ‘203Z’ background) were used as experimental materials. The results suggested that soluble sugar consist of fructose, glucose and sucrose while malic-, citric-, and oxalic acids are the primary organic acids in watermelon fruit. Several differentially expressed genes (DEGs) related to soluble sugar- and organic acid accumulation and metabolism were identified. These include the DEGs encoding raffinose synthase, sucrose synthase (SuSy), sucrose-phosphate synthase (SPSs), insoluble acid invertases (IAI), NAD-dependent malate dehydrogenase (NAD-cyt MDH), aluminum-activated malate transporter (ALMT), and citrate synthase (CS). This is the first report addressing comparative transcriptome analysis via NILs materials in watermelon fruit. These findings provide an important basis for understanding the molecular mechanism that leads to soluble sugar and organic acid accumulation and metabolism during watermelon fruit development and ripening. PMID:29324867

Comparative transcriptome analysis reveals key genes potentially related to soluble sugar and organic acid accumulation in watermelon.

Directory of Open Access Journals (Sweden)

Lei Gao

Full Text Available Soluble sugars and organic acids are important components of fruit flavor and have a strong impact on the overall organoleptic quality of watermelon (Citrullus lanatus fruit. Several studies have analyzed the expression levels of the genes related to soluble sugar accumulation and the dynamic changes in their content during watermelon fruit development and ripening. Nevertheless, to date, there have been no reports on the organic acid content in watermelon or the genes regulating their synthesis. In this study, the soluble sugars and organic acids in watermelon were measured and a comparative transcriptome analysis was performed to identify the key genes involved in the accumulation of these substances during fruit development and ripening. The watermelon cultivar '203Z' and its near-isogenic line (NIL 'SW' (in the '203Z' background were used as experimental materials. The results suggested that soluble sugar consist of fructose, glucose and sucrose while malic-, citric-, and oxalic acids are the primary organic acids in watermelon fruit. Several differentially expressed genes (DEGs related to soluble sugar- and organic acid accumulation and metabolism were identified. These include the DEGs encoding raffinose synthase, sucrose synthase (SuSy, sucrose-phosphate synthase (SPSs, insoluble acid invertases (IAI, NAD-dependent malate dehydrogenase (NAD-cyt MDH, aluminum-activated malate transporter (ALMT, and citrate synthase (CS. This is the first report addressing comparative transcriptome analysis via NILs materials in watermelon fruit. These findings provide an important basis for understanding the molecular mechanism that leads to soluble sugar and organic acid accumulation and metabolism during watermelon fruit development and ripening.

Comparative transcriptome analysis reveals key genes potentially related to soluble sugar and organic acid accumulation in watermelon.

Science.gov (United States)

Gao, Lei; Zhao, Shengjie; Lu, Xuqiang; He, Nan; Zhu, Hongju; Dou, Junling; Liu, Wenge

2018-01-01

Soluble sugars and organic acids are important components of fruit flavor and have a strong impact on the overall organoleptic quality of watermelon (Citrullus lanatus) fruit. Several studies have analyzed the expression levels of the genes related to soluble sugar accumulation and the dynamic changes in their content during watermelon fruit development and ripening. Nevertheless, to date, there have been no reports on the organic acid content in watermelon or the genes regulating their synthesis. In this study, the soluble sugars and organic acids in watermelon were measured and a comparative transcriptome analysis was performed to identify the key genes involved in the accumulation of these substances during fruit development and ripening. The watermelon cultivar '203Z' and its near-isogenic line (NIL) 'SW' (in the '203Z' background) were used as experimental materials. The results suggested that soluble sugar consist of fructose, glucose and sucrose while malic-, citric-, and oxalic acids are the primary organic acids in watermelon fruit. Several differentially expressed genes (DEGs) related to soluble sugar- and organic acid accumulation and metabolism were identified. These include the DEGs encoding raffinose synthase, sucrose synthase (SuSy), sucrose-phosphate synthase (SPSs), insoluble acid invertases (IAI), NAD-dependent malate dehydrogenase (NAD-cyt MDH), aluminum-activated malate transporter (ALMT), and citrate synthase (CS). This is the first report addressing comparative transcriptome analysis via NILs materials in watermelon fruit. These findings provide an important basis for understanding the molecular mechanism that leads to soluble sugar and organic acid accumulation and metabolism during watermelon fruit development and ripening.

Intrinsic solubility estimation and pH-solubility behavior of cosalane (NSC 658586), an extremely hydrophobic diprotic acid.

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Venkatesh, S; Li, J; Xu, Y; Vishnuvajjala, R; Anderson, B D

1996-10-01

The selection of cosalane (NSC 658586) by the National Cancer Institute for further development as a potential drug candidate for the treatment of AIDS led to the exploration of the solubility behavior of this extremely hydrophobic drug, which has an intrinsic solubility (S0 approaching 1 ng/ml. This study describes attempts to reliably measure the intrinsic solubility of cosalane and examine its pH-solubility behavior. S0 was estimated by 5 different strategies: (a) direct determination in an aqueous suspension: (b) facilitated dissolution; (c) estimation from the octanol/water partition coefficient and octanol solubility (d) application of an empirical equation based on melting point and partition coefficient; and (e) estimation from the hydrocarbon solubility and functional group contributions for transfer from hydrocarbon to water. S0 estimates using these five methods varied over a 5 x 107-fold range Method (a) yielded the highest values, two-orders of magnitude greater than those obtained by method (b) (facilitated dissolution. 1.4 +/- 0.5 ng/ml). Method (c) gave a value 20-fold higher while that from method (d) was in fair agreement with that from facilitated dissolution. Method (e) yielded a value several orders-of-magnitude lower than other methods. A molecular dynamics simulation suggests that folded conformations not accounted for by group contributions may reduce cosalane's effective hydrophobicity. Ionic equilibria calculations for this weak diprotic acid suggested a 100-fold increase in solubility per pH unit increase. The pH-solubility profile of cosalane at 25 degrees C agreed closely with theory. These studies highlight the difficulty in determining solubility of very poorly soluble compounds and the possible advantage of the facilitated dissolution method. The diprotic nature of cosalane enabled a solubility enhancement of > 107-fold by simple pH adjustment.

Natural polymers: Best carriers for improving bioavailability of poorly water soluble drugs in solid dispersions

OpenAIRE

Sandip Sapkal; Mahesh Narkhede; Mukesh Babhulkar; Gautam Mehetre; Ashish Rathi

2013-01-01

ABSTRACTNatural polymers and its modified forms can be used as best alternative for improving bioavailabilityof poorly water soluble drugs in solid dispersion. Most of the natural polymersare hydrophilic and having high swelling capacity. Recent trend towards the use of naturalpolymer demands the replacement of synthetic additives with natural ones. Many plant derivednatural polymers are studied for use in solid dispersion systems, out of which naturalgums, cyclodextrin and carbohydrate are m...

Solubility of iron from combustion source particles in acidic media linked to iron speciation.

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Fu, Hongbo; Lin, Jun; Shang, Guangfeng; Dong, Wenbo; Grassian, Vichi H; Carmichael, Gregory R; Li, Yan; Chen, Jianmin

2012-10-16

In this study, iron solubility from six combustion source particles was investigated in acidic media. For comparison, a Chinese loess (CL) dust was also included. The solubility experiments confirmed that iron solubility was highly variable and dependent on particle sources. Under dark and light conditions, the combustion source particles dissolved faster and to a greater extent relative to CL. Oil fly ash (FA) yielded the highest soluble iron as compared to the other samples. Total iron solubility fractions measured in the dark after 12 h ranged between 2.9 and 74.1% of the initial iron content for the combustion-derived particles (Oil FA > biomass burning particles (BP) > coal FA). Ferrous iron represented the dominant soluble form of Fe in the suspensions of straw BP and corn BP, while total dissolved Fe presented mainly as ferric iron in the cases of oil FA, coal FA, and CL. Mössbauer measurements and TEM analysis revealed that Fe in oil FA was commonly presented as nanosized Fe(3)O(4) aggregates and Fe/S-rich particles. Highly labile source of Fe in corn BP could be originated from amorphous Fe form mixed internally with K-rich particles. However, Fe in coal FA was dominated by the more insoluble forms of both Fe-bearing aluminosilicate glass and Fe oxides. The data presented herein showed that iron speciation varies by source and is an important factor controlling iron solubility from these anthropogenic emissions in acidic solutions, suggesting that the variability of iron solubility from combustion-derived particles is related to the inherent character and origin of the aerosols themselves. Such information can be useful in improving our understanding on iron solubility from combustion aerosols when they undergo acidic processing during atmospheric transport.

Characterization of a soluble phosphatidic acid phosphatase in bitter melon (Momordica charantia).

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Cao, Heping; Sethumadhavan, Kandan; Grimm, Casey C; Ullah, Abul H J

2014-01-01

Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53-60 °C and unaffected by up to 0.3 mM MgCl2. The K(m) and Vmax values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO4 and CuSO4, but stimulated by MnSO4, ZnSO4 and Co(NO3)2. In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants.

Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.

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Popović, Gordana; Cakar, Mira; Agbaba, Danica

2009-01-15

Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65x10(-6) M and 3.82x10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (DeltapK(a)) ranged from -2.24 to +1.24.

Le Chatelier's Principle: The Effect of Temperature on the Solubility of Solids in Liquids.

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Brice, L. K.

1983-01-01

Provides a rigorous but straightforward thermodynamic treatment of the temperature dependence of the solubility of solids in liquids that is suitable for presentation to undergraduates, suggesting how to approach the qualitative aspects of the subject for freshmen. Considers unsolvated/solvated solutes and Le Chatelier's principle. (JN)

Method to separate lignin-rich solid phase from acidic biomass suspension at an acidic pH

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Yasarla, Kumar Lakshmi Rakesh; Ramarao, Bandaru V; Amidon, Thomas

2017-09-05

A method of separating a lignin-rich solid phase from a solution suspension, by pretreating a lignocellulosic biomass with a pretreatment fluid having remove soluble components, colloidal material and primarily lignin containing particles; separating the pretreated lignocellulosic biomass from the pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles; flocculating the separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles using polyethylene oxide (i.e., PEO) or cationic Poly acrylamide (i.e., CPAM) as a flocculating agent; and filtering the flocculated separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles to remove agglomerates.

Variation of Soluble Solids Concentration During the Day in Three Pastures During the Dry Season in the Middle River Sinú Valley

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Emiro Suárez Paternina

2015-07-01

Full Text Available The aim of this study was to determine the concentration of soluble solids at different times of the day in three tropical pastures. The experiment was conducted at the Research Center Turipaná of Colombian Agricultural Research Corporation, located in Cereté, Colombia. During January and February of 2011, we assessed the concentration of soluble solids in three fertirrigated pastures: Panicum maximum, Cynodon nlemfuensis and Brachiaria hybrid cv. Mulato II, in an intensive model of meat production at different sampling times 7:00 and 10:00 a. m., 1:00 and 4:00 p.m. The statistical design of the experiment consisted of a block design completely randomized three-factor under 3*3*4 (pasture*stocking*time and three replicates for each evaluation day. An analysis of variance and differences were statistically significant when the means were separated by Tukey test (p<0.05. The analysis found highly significant differences (p<0.01 in the concentration of soluble solids in different pastures, in all periods of the day evaluated, with the cultivar Mulato II that presented the highest values with 9.19 %, followed by Cynodon nlemfuensis and Panicum maximum with 8.27 % and 7.07 %, respectively. The soluble solids concentration varied during the day and between pastures. The time periods close to noon —10:00 a. m. and 1:00 p. m.— presented the highest concentrations of soluble solids in all pastures; this can be used as a tool for paddock rotation.

Influence of biopolymers on the solubility of branched-chain amino acids and stability of their solutions.

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Hong, Chi Rac; Lee, Gyu Whan; Paik, Hyun-Dong; Chang, Pahn-Shick; Choi, Seung Jun

2018-01-15

This study confirmed the possibility of biopolymer-type stabilizers to increase the saturation concentration of branched-chain amino acids by preventing their crystallization/precipitation. Although microfluidization increased the initial solubility, it failed to increase the saturation concentration of the branched-chain amino acids. The saturation concentration of the branched-chain amino acids increased from 3.81% to 4.42% and 4.85% after the incorporation of food hydrocolloids and proteins, respectively. However, the branched-chain amino acids:stabilizer ratio did not affect the solubility. In the case of food hydrocolloid-based solutions, crystal formation and growth of branched-chain amino acids occurred during storage, resulting in the precipitation of branched-chain amino acid crystals. However, food proteins effectively increased the stability of the solubilized branched-chain amino acids. The improved solubility and stability of the solubilized branched-chain amino acids could be attributed to interactions between the functional groups (carboxyl, amine, sulfate, aliphatic, aromatic, etc.) of the stabilizer and the branched-chain amino acid molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heat capacity and solid solubility of iron in scandium

International Nuclear Information System (INIS)

Tsang, T.-W.E.

1981-01-01

The maximum solid solubility of iron in scandium was determined to be between 50 and 85 at.ppm in the as-cast condition. As the concentration of iron increases, it segregates along the grain boundary, as is evident from optical metallography and electron microprobe examinations. Annealing also causes the iron dissolved in scandium to separate out and cluster along the grain boundary. Heat capacity measurements show an anomaly in the C/T versus T 2 plots for iron concentrations of 19 at.ppm or greater. For iron dissolved in solid scandium the excess entropy due to the iron impurity is in agreement with the theoretical prediction of ck ln(2S + 1) for an impurity-conduction electron (Kondo) interaction, but is 4 - 8 times larger than the theoretical prediction when iron segregates along the grain boundary. Furthermore, our results suggest that most of the previously reported low temperature physical properties of scandium are probably in error because of either iron impurity-conduction electron interactions or Fe-Fe interactions in the precipitated second-phase Sc-Fe compound. (Auth.)

Influence of solid state fermentation by Trichoderma spp. on solubility, phenolic content, antioxidant, and antimicrobial activities of commercial turmeric.

Science.gov (United States)

Mohamed, Saleh A; Saleh, Rashad M; Kabli, Saleh A; Al-Garni, Saleh M

2016-05-01

The influence of solid state fermentation (SSF) by Trichoderma spp. on the solubility, total phenolic content, antioxidant, and antibacterial activities of turmeric was determined and compared with unfermented turmeric. The solubility of turmeric was monitored by increase in its phenolic content. The total phenolic content of turmeric extracted by 80% methanol and water after SSF by six species of Trichoderma spp. increased significantly from 2.5 to 11.3-23.3 and from 0.5 to 13.5-20.4 GAE/g DW, respectively. The antioxidant activities of fermented turmeric were enhanced using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS), and ferric ion-reducing antioxidant power (FRAP) assays. The antibacterial activity of fermented turmeric against human-pathogenic bacteria Escherichia coli, Streptococcus agalactiae, Staphylococcus aureus, Entreococcus faecalis, Methicillin-Resistant S. aureus, Klebsiella pneumonia, and Pseudomonas aeruginosae showed a broad spectrum inhibitory effect. In conclusion, the results indicated the potentials of using fermented turmeric as natural antioxidant and antimicrobial material for food applications.

Microemulsion formulation of clonixic acid: solubility enhancement and pain reduction.

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Lee, Jung-Mi; Park, Kyung-Mi; Lim, Soo-Jeong; Lee, Mi-Kyung; Kim, Chong-Kook

2002-01-01

Clonixic acid is currently marketed as a salt form because of its poor water-solubility. However, the commercial dosage form causes severe pain after intramuscular or intravenous injection. To improve the solubility of clonixic acid and to reduce pain on injection, clonixic acid was incorporated into oil-in-water microemulsions prepared from pre-microemulsion concentrate composed of varying ratios of oil and surfactant mixture. As an oil phase for drug incorporation, up to 14% castor oil could be included in the pre-microemulsion concentrate without a significant increase in droplet size. Both drug contents and droplet size increased as the weight ratio of Tween 20 to Tween 85 decreased. Taken together, when microemulsions were prepared from pre-microemulsion concentrate composed of 5:12:18 weight ratio of castor oil:Tween 20:Tween 85, clonixic acid could be incorporated at 3.2 mg mL(-1) in the microemulsion with a droplet size of less than 120 nm. The osmotic pressure of this microemulsion was remarkably lower than the commercial formulation, irrespective of the dilution ratios. The rat paw-lick test was used to compare pain responses among formulations. The microemulsion formulation significantly reduced the number of rats licking their paws as well as the total licking time, suggesting less pain induction by the microemulsion formulation. The pharmacokinetic parameters of clonixic acid after intravenous administration of the clonixic acid microemulsion to rats were not significantly different from those of the commercial formulation, lysine clonixinate. The present study suggests that microemulsion is an alternative formulation for clonixic acid with improved characteristics.

Recent Progress in the Development of Supercritical Carbon Dioxide-Soluble Metal Ion Extractants: Aggregation, Extraction, and Solubility Properties of Silicon-Substituted Alkylenediphosphonic Acids

Energy Technology Data Exchange (ETDEWEB)

Dietz, Mark L.; McAlister, Daniel R.; Stepinski, Dominique C.; Zalupski, Peter R.; Dzilawa, Julie A.; Barrans, Richard E.; Hess, J.N.; Rubas, Audris V.; Chiarizia, Renato; Lubbers, Christopher M.; Scurto, Aaron M.; Brennecke, Joan F.; Herlinger, Albert W.

2003-09-11

Partially esterified alkylenediphosphonic acids (DPAs) have been shown to be effective reagents for the extraction of actinide ions from acidic aqueous solution into conventional organic solvents. Efforts to employ these compounds in supercritical fluid extraction have been hampered by their modest solubility in unmodified supercritical carbon dioxide (SC-CO2). In an effort to design DPAs that are soluble in SC-CO2, a variety of silicon-substituted alkylenediphosphonic acids have been prepared and characterized, and their behavior compared with that of conventional alkyl-substituted reagents. Silicon substitution is shown to enhance the CO2-philicity of the reagents, while other structural features, in particular, the number of methylene groups bridging the phosphorus atoms of the extractant, are shown to exert a significant influence on their aggregation and extraction properties. The identification of DPAs combining desirable extraction properties with adequate solubility in SC-CO2 is shown to be facilitated by the application of molecular connectivity indices.

The mechanisms of drug release from solid dispersions in water-soluble polymers.

Science.gov (United States)

Craig, Duncan Q M

2002-01-14

Solid dispersions in water-soluble carriers have attracted considerable interest as a means of improving the dissolution rate, and hence possibly bioavailability, of a range of hydrophobic drugs. However, despite the publication of numerous original papers and reviews on the subject, the mechanisms underpinning the observed improvements in dissolution rate are not yet understood. In this review the current consensus with regard to the solid-state structure and dissolution properties of solid dispersions is critically assessed. In particular the theories of carrier- and drug-controlled dissolution are highlighted. A model is proposed whereby the release behaviour from the dispersions may be understood in terms of the dissolution or otherwise of the drug into the concentrated aqueous polymer layer adjacent to the solid surface, including a derivation of an expression to describe the release of intact particles from the dispersions. The implications of a deeper understanding of the dissolution mechanisms are discussed, with particular emphasis on optimising the choice of carrier and manufacturing method and the prediction of stability problems.

Fast Measurement of Soluble Solid Content in Mango Based on Visible and Infrared Spectroscopy Technique

Science.gov (United States)

Yu, Jiajia; He, Yong

Mango is a kind of popular tropical fruit, and the soluble solid content is an important in this study visible and short-wave near-infrared spectroscopy (VIS/SWNIR) technique was applied. For sake of investigating the feasibility of using VIS/SWNIR spectroscopy to measure the soluble solid content in mango, and validating the performance of selected sensitive bands, for the calibration set was formed by 135 mango samples, while the remaining 45 mango samples for the prediction set. The combination of partial least squares and backpropagation artificial neural networks (PLS-BP) was used to calculate the prediction model based on raw spectrum data. Based on PLS-BP, the determination coefficient for prediction (Rp) was 0.757 and root mean square and the process is simple and easy to operate. Compared with the Partial least squares (PLS) result, the performance of PLS-BP is better.

Dehydration of alcohols using solid acid catalysts

OpenAIRE

Cholerton, Mary

2014-01-01

Solid acid catalysts were prepared through silicon substitution into aluminophosphate frameworks. Silicon incorporation was confirmed using solid state nuclear magnetic resonance spectroscopy. The nature of the acid sites generated was determined using Fourier Transform infrared spectroscopy. These materials were tested as catalysts for the dehydration of ethanol to ethylene at low operating temperatures. The materials were active for dehydration of ethanol to ethylene with significant differ...

Investigations on uranyl nitrate solubility in nitric acid in different concentrations at temperatures of 50C

International Nuclear Information System (INIS)

Deigele, E.

1983-01-01

The solubility of uranyl nitrate was studied in nitric acid solutions of different concentrations at a temperature of 5 0 C. This temperature was chosen with a view to using water as coolant and to facilitate the handling of the strong acid solutions. Accurate curves were established by a multitude of accurate measurements in the high concentration range. Further solubility curves can be derived from this basic curve. Some of the precipitates in the interesting regions of the solubility curve were analyzed. (orig./EF) [de

Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

African Journals Online (AJOL)

Atmospheric aerosol samples of PM2.5 and PM10 were collected in April–May 2011 from a rural site in Tanzania and analyzed for water-soluble inorganic ions and low molecular weight carboxylic acids using ion chromatography. PM2.5 and PM10 low-volume samplers with quartz fibre filters were deployed and aerosol ...

Measurement and modelling of urea solubility in aqueous propane-1,2,3-triol and prop-2-enoic acid solutions

International Nuclear Information System (INIS)

Santos, Jéssica dos J; Rocha, João A.A.B.; Costa, Glória M.N.; Cabral-Albuquerque, Elaine C.M.; Alves, Tito L.M.; Pinto, José C.; Fialho, Rosana L.

2016-01-01

Highlights: • Solubilities were shown to increase with temperature and to decrease with the increasing organic solvent content. • The UNIFAC method provided good fitting of the available data, after the estimation of a single model parameter. • The empirical method showed to be more efficient to describe several solution concentrations however, it is not predictive. - Abstract: The aim of the present study is to measure the solubility of urea in aqueous solutions of prop-2-enoic acid and propane-1,2,3-triol, as these compounds are used as co-monomers to produce urea base co-polymers. Experimental values have been obtained at several concentrations and temperatures. Solubility results were modelled with the help of an exponential empirical correlation, ideal solid-liquid equilibrium correlation and the Universal Functional Activity Coefficient (UNIFAC) method, used to describe the activity coefficient in the liquid phase. The empirical correlation requires two empirical parameters for each solvent and leads to the best fit for the available data. The UNIFAC method correlation also has a good numerical performance and is completely predictive, and it does not require the estimation of additional parameters.

Study of the solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium in sulfuric-phosphoric acid solutions at 20 deg C

International Nuclear Information System (INIS)

Lokshin, Eh.P.; Tareeva, O.A.; Kashulina, T.G.

2007-01-01

The solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium ions and the composition of solid phases were studied at 20 deg C in relation to the concentration of acids in sulfuric acid, phosphoric acid, and sulfuric-phosphoric acid solutions containing up to 36 wt % H 2 SO 4 and 33.12 g 1 -1 H 3 PO 4 . The formation of double sulfates of praseodymium and neodymium with sodium and potassium ions, as well as of gadolinium sulfate with sodium ions of the composition 1 : 1 was revealed. In water at 20 deg C, the solubility products of PrNa(SO 4 ) 2 ·H 2 O, NdNa(SO 4 ) 2 ·H 2 O, GdNa(SO 4 ) 2 ·H 2 O, PrK(SO 4 ) 2 ·H 2 O, and NdK(SO 4 ) 2 ·H 2 O are found to be 7.28x10 -8 , 7.84x10 -8 , 3.09x10 -6 , 3.02x10 -6 , and 1.70x10 -6 , respectively [ru

Sustained Cytotoxicity of Wogonin on Breast Cancer Cells by Encapsulation in Solid Lipid Nanoparticles

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Jong-Suep Baek

2018-03-01

Full Text Available While wogonin has been known to have cytotoxicity against various cancer cells, its bioavailability and cytotoxicity are low due to its low water solubility. Therefore, wogonin-loaded solid lipid nanoparticles were fabricated using a hot-melted evaporation technique. The highest solubility of wogonin was observed in stearic acid. Hence, wogonin-loaded solid lipid nanoparticles were composed of stearic acid as the lipid matrix. The physicochemical properties of the wogonin-loaded solid lipid nanoparticles were evaluated by dynamic laser scattering and scanning electron microscopy. The wogonin-loaded solid lipid nanoparticles exhibited sustained and controlled release up to 72 h. In addition, it was observed that the wogonin-loaded solid lipid nanoparticles exhibited enhanced cytotoxicity and inhibited poly (ADP-ribose polymerase in MCF-7 breast cancer cells. Overall, the results indicate that wogonin-loaded solid lipid nanoparticles could be an efficient delivery system for the treatment of breast cancer.

Efficient Enzymatic Synthesis of Phenolic Ester by Increasing Solubility of Phenolic Acids in Ionic Liquids

DEFF Research Database (Denmark)

Yang, Zhiyong; Guo, Zheng; Xu, Xuebing

Compounds from phenolic acid family are well known natural antioxidants, but the application of phenolic acids as antioxidants in industry is limited due to the relatively low solubility in oil-based media. The properties of phenolic acids can be modified through enzymatic lipophilization...... and modified phenolic acids will have amphiphilic property, therefore they can be localized at oil-water or water-oil phase where oxidation is considered to occur frequently. It had been reported that immobilized Candida Antarctica lipase B was the most effective biocatalyst for the various esterification...... reactions, and it had been widely used for esterification of various phenolic acids with fatty alcohol or triglycerides. However, the conversion of phenolic acids is low due to low solubility in hydrophobic solvents and hindrance effect of unsaturated side chain towards the enzyme. Our studies show...

Solid dispersions: a strategy for poorly aqueous soluble drugs and technology updates.

Science.gov (United States)

Alam, Mohd Aftab; Ali, Raisuddin; Al-Jenoobi, Fahad Ibrahim; Al-Mohizea, Abdullah M

2012-11-01

Present article reviews solid dispersion (SD) technologies and other patented inventions in the area of pharmaceutical SDs, which provide stable amorphous SDs. The review briefly compiles different techniques for preparing SDs, their applications, characterization of SDs, types of SDs and also elaborates the carriers used to prepare SDs. The advantages of recently introduced SD technologies such as RightSize(™), closed-cycle spray drying (CSD), Lidose® are summarized. Stability-related issues like phase separation, re-crystallization and methods to curb these problems are also discussed. A patented carrier-screening tool for predicting physical stability of SDs on the basis of drug-carrier interaction is explained. Applications of SD technique in controlled drug delivery systems and cosmetics are explored. Review also summarizes the carriers such as Soluplus®, Neusilin®, Solumer(TM) used to prepare stable amorphous SD. Binary and ternary SDs are found to be more stable and provide better enhancement of solubility or dissolution of poorly water-soluble drugs. The use of surfactants in the carrier system of SD is a recent trend. Surfactants and polymers provide stability against re-crystallization of SDs, surfactants also improve solubility and dissolution of drug.

INVESTIGATION OF THE PHARMACO-TECHNOLOGICAL PROPERTIES OF SOLID DISPERSIONS OF THIOCTIC ACID, OBTAINED BY MICRONIZATION

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Kovalevska, I. V.

2018-04-01

Full Text Available Introduction. Thioctic acid is used in the treatment of diseases that are characterized by lack of mitochondrial activity, which is responsible for the formation of free radicals. Widespread use of thioctic acid is due to the chemical structure. The thioctic acid exhibits biological activity in both hydrophilic and hydrophobic environments. Thioctic acid is an enzyme cofactor and a powerful antioxidant, it regulates the transcription of numerous genes, participates in regulation of glucose and lipid metabolism, increases insulin sensitivity, and forms complexes with heavy metals. Thioctic acid has a high pharmacological potential, which is confirmed by the evidence base of clinical trials. An analysis of the literature on the oral use of thioctic acid indicates that solid dosage forms can be used for long-term therapy. This route of administration is limited by factors such as reduced solubility in acidic environments and enzymatic degradation. For this reason, the search for various compositions of auxiliary substances and methods of obtaining drugs is an urgent task of pharmaceutical technology. Material & methods. Objects of study were solid dispersions of thioctic acid (SDTA on the basis of cellulose derivatives: microcrystalline (MCC, HPMC (hydroxypropyl methylcellulose and polyvinylpyrrolidone (PVP as compared to thioctic acid (TA. The samples were made by solid phase method using micronization in a laboratory shredder at a ratio of 1: 1. Pharmacological and technological parameters were determined according to generally accepted methods. Results & discussion. In appearance the resulting mixtures had lemon color, without inclusions and the formation of conglomerates, with homogeneous sized particles According to the pharmaco-technological studies, the samples do not have a satisfactory flowability. The values of the Carr index and the ratio of Hausner make it possible to conclude that there is a large force of cohesion between the

Characterization of Acid Soluble Collagen from Redbelly Yellowtail Fusilier Fish Skin (Caesio cuning

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Ika Astiana

2016-04-01

Full Text Available Fish skin can be used as raw material for producing collagen. The collagen can be extracted by chemical or combination of chemical and enzymatic processes. Extraction of collagen chemically can do with the acid process that produces acid soluble collagen (ASC. This study aimed to determine the optimum concentration and time of pretreatment and extraction, also to determine the characteristics of the acid soluble collagen from the skin of yellow tail fish. Extraction of collagen done by pretreatment using NaOH at the concentration of 0.05; 0.1; and 0.15 M and extraction using acetic acid at the concentration of 0.3; 0.5; and 0.7 M. Pretreatment NaOH with concentration 0.05 M and soaking time of 8 hours is the best combination for eliminating non collagen protein. Combination treatment of acetic acid at the concentration of 0.3 M for 3 days obtained the best solubility. The yield of collagen ASC was 18.4±1.49% (db and 5.79±0.47% (wb. Amino acid composition that is dominant in the ASC collagen was glycine (25.09±0.003%, alanine (13.71±0.075%, and proline (12.15±0.132%. Collagen from yellow tail fish skin has α1, α2, β and γ protein structure with the molecular weight of 125, 113, 170-181, and 208 KDa. The transition and melting temperatures of collagen were 67.69oC and 144.4oC. The surface structure of collagen by analysis of SEM has fibers on the surface.

The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

Energy Technology Data Exchange (ETDEWEB)

Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2015-09-25

Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

International Nuclear Information System (INIS)

Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

2015-01-01

Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

Determination and modeling of binary and ternary solid-liquid phase equilibrium for the systems formed by 3,5-dinitrobenzoic acid, m-nitrobenzoic acid and acetone

International Nuclear Information System (INIS)

Li, Xinbao; Du, Cunbin; Zhao, Hongkun

2017-01-01

Highlights: • The solubility of 3,5-dinitrobenzoic acid in acetone was determined. • Solubility of m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone was determined. • Three ternary phase diagrams were constructed for the ternary system. • The ternary phase diagrams were calculated by Wilson model and NRTL model. - Abstract: The solubility of 3,5-dinitrobenzoic acid in acetone at the temperatures ranging from (283.15 to 318.15) K and the mutual solubility of the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system at (283.15, 298.15 and 313.15) K were determined experimentally by using the isothermal saturation method under atmosphere pressure (101.2 kPa). Three isothermal ternary phase diagrams were constructed according to the measured mutual solubility data. In each ternary phase diagram, there was one co-saturated point, two boundary curves, and three crystalline regions. The modified Apelblat equation, λh equation, NRTL model and Wilson model were used to correlate the solubility of 3,5-dinitrobenzoic acid in acetone; and the NRTL and Wilson models, the mutual solubility for the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system. The value of root-mean-square deviation (RMSD) was 8.53 × 10 −4 for the binary system of 3,5-dinitrobenzoic acid + acetone; and the largest value of RMSD was 81.08 × 10 −4 for the ternary system.

Solubility Testing of Sucrose Esters of Fatty Acids in International Food Additive Specifications.

Science.gov (United States)

Nagai, Yukino; Kawano, Satoko; Motoda, Kenichiro; Tomida, Masaaki; Tatebe, Chiye; Sato, Kyoko; Akiyama, Hiroshi

2017-03-01

We investigated the solubility of 10 samples of sucrose esters of fatty acids (SEFA) products that are commercially available worldwide as food additives (emulsifiers). Although one sample dissolved transparently in both water and ethanol, other samples produced white turbidity and/or precipitates and did not meet the solubility criterion established by the Joint Food and Agriculture Organization of the United Nations (FAO)/WHO Expert Committee on Food Additives (JECFA). When the sample solutions were heated, the solubility in both water and ethanol increased. All of the samples dissolved transparently in ethanol, and dispersed and became white without producing precipitates in water. The present study suggests that the current solubility criterion of the JECFA SEFA specifications needs to be revised.

Method for measurement of radon diffusion and solubility in solid materials

Science.gov (United States)

Maier, Andreas; Weber, Uli; Dickmann, Jannis; Breckow, Joachim; van Beek, Patrick; Schardt, Dieter; Kraft, Gerhard; Fournier, Claudia

2018-02-01

In order to study the permeation i.e. the diffusion and solubility of radon gas in biological material, a new setup was constructed and a novel analysis was applied to obtain diffusion and solubility coefficients. Thin slabs of solid materials were installed between detector housing and the surrounding radon exposure chamber of 50 Ls volume. In this setup radon can diffuse through thin test samples into a cylindrical volume of 5 mm height and 20 mm diameter and reach an α-particle detector. There the 5.49 MeV α-decay of the penetrating radon atoms is measured by a silicon surface barrier detector. The time dependent activities inside the small detector volume are recorded after injection of a known radon activity concentration into the outer chamber. Analyzing the time behavior of the integral α-activity from radon in the small vessel, both, the diffusion coefficient and solubility of the test material can be determined, based on a new mathematical model of the diffusion process concerning the special boundary conditions given by the experimental setup. These first measurements were intended as proof of concept for the detection system and the data analysis. Thin polyethylene foils (LDPE) were selected as material for the diffusion measurements and the results were in agreement with data from literature. In further measurements, we will concentrate on biological material like bone, fat and other tissues.

Radiation-induced reactions of amino acids adsorbed on solid surfaces

Energy Technology Data Exchange (ETDEWEB)

Lopez-Esquivel Kranksith, L.; Negron-Mendoza, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico); Mosqueira, F.G. [Direcion General de Divulgacion de la Ciencia, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, AP. 70-487 Mexico D.F. (Mexico); Ramos-Bernal, Sergio, E-mail: ramos@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico)

2010-07-21

The purpose of this work is to study the adsorption of compounds such as amino acids on clays and carbon nanotubes (CNTs) as a possible phase in the chemical evolution that may have occurred on the primitive Earth or in extraterrestrial environments. We further study the behavior of amino acids adsorbed on these solid surfaces at different conditions of pH and levels of irradiation, simulating a high-radiation field at early Earth conditions. The relevance of this work is to explain the possible contribution of solids (clays and CNTs) as promoters of polymerization and as shields for the adsorbed organic compounds against external sources of energy. To this end, tryptophan, aspartic acid, and glutamic acid were adsorbed on fixed amounts of solid surfaces and were irradiated by a {sup 60}Co source for different periods of time at fixed dose rates. After irradiation, the amino acids were extracted from the solid and analyzed with UV and IR spectroscopes and high-performance liquid chromatography. The most efficient surface for adsorption of amino acids was clay, followed by CNTs. Studies of the gamma irradiation of amino acids adsorbed on clay (in the solid phase) show a low yield of recovery of the amino acid.

Efficient Route to Highly Water-Soluble Aromatic Cyclic Hydroxamic Acid Ligands

Energy Technology Data Exchange (ETDEWEB)

Seitz, Michael; Raymond, Kenneth N.

2008-02-06

2-Hydroxyisoquinolin-1-one (1,2-HOIQO) is a new member of the important class of aromatic cyclic hydroxamic acid ligands which are widely used in metal sequestering applications and metal chelating therapy. The first general approach for the introduction of substituents at the aromatic ring of the chelating moiety is presented. As a useful derivative, the highly water-soluble sulfonic acid has been synthesized by an efficient route that allows general access to 1,2-HOQIO 3-carboxlic acid amides, which are the most relevant for applications.

Solubility of 3-Caffeoylquinic Acid in Different Solvents at 291-340 K

Science.gov (United States)

Wang, Y. T.; Zhang, C. L.; Cheng, X. L.; Zhao, J. H.; Wang, L. C.

2017-12-01

Using a laser monitoring observation technique the solubilities of 3-caffeoylquinic acid in pure solvents, water, methanol, ethanol, 1-propanol, 1-butanol, and two mixed solvents, methanol + water, ethanol + water have been determined at temperature range from 291-340 K. The experimental data were correlated by the modified Apelblat equation, λ h equation, and ideal model. The calculated solubilities were turned out very consistent with the experimental results, and the modified Apelblat equation shows the best agreement.

Neptunium (IV) oxalate solubility

International Nuclear Information System (INIS)

Luerkens, D.W.

1983-07-01

The equilibrium solubility of neptunium (IV) oxalate in nitric/oxalic acid solutions was determined at 22 0 C, 45 0 C, and 60 0 C. The concentrations of nitric/oxalic acid solutions represented a wide range of free oxalate ion concentration. A mathematical solubility model was developed which is based on the formation of the known complexes of neptunium (IV) oxalate. the solubility model uses a simplified concentration parameter which is proportional to the free oxalate ion concentration. The solubility model can be used to estimate the equilibrium solubility of neptunium (IV) oxalate over a wide range of oxalic and nitric acid concentrations at each temperature

Bulk diffusion and solubility of silver and nickel in lead, lead-silver and lead-nickel solid solutions

International Nuclear Information System (INIS)

Amenzou-Badrour, H.; Moya, G.; Bernardini, J.

1988-01-01

The results of a study of solubility and bulk diffusion of /sup 110/Ag and /sup 63/Ni in lead, lead-silver and lead-nickel solid solutions in the temperature range 220 to 88 0 C are reported. Owing to the low solubility of silver and nickel in lead, Fick's solution corresponding to the boundary condition of a constant concentration of solute at the surface has been used. Depth profile concentration analysis suggests a fundamental difference between the diffusion mechanisms of silver and nickel. Since silver penetration profiles in pure lead give diffusion coefficients independent of the penetration depth and silver concentration, it is suggested that slight decreases of silver diffusivity in lead-silver solid solutions have no significance. This implies that the interstitial silver atoms do not associate significantly with each other to form Ag-Ag dimers. In contrast, different behaviors of /sup 63/Ni depth profile concentration in pure lead and saturated PbNi solid solutions agree with a Ni-Ni interaction leading to the formation of less mobile dimers near the surface in pure lead

Properties of spores of Bacillus subtilis strains which lack the major small, acid-soluble protein

International Nuclear Information System (INIS)

Hackett, R.H.; Setlow, P.

1988-01-01

Bacillus subtilis strains containing a deletion in the gene coding for the major small, acid-soluble, spore protein (SASP-gamma) grew and sporulated, and their spores initiated germination normally, but outgrowth of SASP-gamma- spores was significantly slower than that of wild-type spores. The absence of SASP-gamma had no effect on spore protoplast density or spore resistance to heat or radiation. Consequently, SASP-gamma has a different function in spores than do the other major small, acid-soluble proteins

Solid dispersions, part II: new strategies in manufacturing methods for dissolution rate enhancement of poorly water-soluble drugs.

Science.gov (United States)

Bikiaris, Dimitrios N

2011-12-01

The absorption of poorly water-soluble drugs, when presented in the crystalline state to the gastrointestinal tract, is typically dissolution rate-limited, and according to BCS these drugs belong mainly to class II. Both dissolution kinetics and solubility are particle size dependent. Nowadays, various techniques are available to the pharmaceutical industry for dissolution rate enhancement of such drugs. Among such techniques, nanosuspensions and drug formulation in solid dispersions are those with the highest interest. This review discusses strategies undertaken over the last 10 years, which have been applied for the dissolution enhancement of poorly water-soluble drugs; such processes include melt mixing, electrospinning, microwave irradiation and the use of inorganic nanoparticles. Many problems in this field still need to be solved, mainly the use of toxic solvents, and for this reason the use of innovative new procedures and materials will increase over the coming years. Melt mixing remains extremely promising for the preparation of SDs and will probably become the most used method in the future for the preparation of solid drug dispersions.

21 CFR 186.1093 - Sulfamic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sulfamic acid. 186.1093 Section 186.1093 Food and... Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3NO3S, CAS Reg. No. 5329-14-6) is a white crystalline solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and...

On the americium oxalate solubility

International Nuclear Information System (INIS)

Zakolupin, S.A.; Korablin, Eh.V.

1977-01-01

The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

Effects of roasting temperatures and gamma irradiation on the content of chlorogenic acid, caffeic acid and soluble carbohydrates of coffee

International Nuclear Information System (INIS)

Deshpande, S.N.; Aguilar, A.A.

1975-01-01

Two varieties of Puerto Rican coffee, Coffea canephora L. var. Robusta, and Coffea arabica L. var. Borbon, were subjected to four different doses of radiation and roasted at two different temperatures. Aqueous extracts of the ground coffee beans were analyzed for chlorogenic acid and caffeic acid at 324 nm and 360 nm wavelength settings, respectively. Samples subjected to the roasting treatments in conjuction with irradiation treatments were treated with basic lead acetate prior to the colorimetric analyses in order to eliminate interfering substances. The total carbohydrate content was also determined by colorimetric techniques with anthrone reagent. The total nitrogen content of the pulverized samples were determined by the micro-Kjeldahl method. While roasting treatments caused a reduction in the concentrations of the chlorogenic acid, caffeic acid, and the carbohydrates, the radiation treatments increased the concentrations of soluble carbohydrates without affecting the concentrations of chlorogenic acid or caffeic acid. It therefore appears that radiation treatments seem to cause degradation of the acid-polysaccharide complexes liberating soluble sugars. There were no noticable changes in the total content of nitrogen caused by roasting or the radiation treatments as indicated by the statistical analysis employing the split plot design. (author)

Development of clinical dosage forms for a poorly water-soluble drug II: formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drug.

Science.gov (United States)

Li, Ping; Hynes, Sara R; Haefele, Thomas F; Pudipeddi, Madhu; Royce, Alan E; Serajuddin, Abu T M

2009-05-01

The solution of a poorly water-soluble drug in a liquid lipid-surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 microg/mL at pH 1-8 and 25 degrees C) was dissolved in a melt of the mixture at 65-70 degrees C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55 degrees C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55-60 degrees C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (PEG 3350 did not interfere with the process of self-microemulsification.

Measurement of soluble solids content in watermelon by Vis/NIR diffuse transmittance technique*

OpenAIRE

Tian, Hai-qing; Ying, Yi-bin; Lu, Hui-shan; Fu, Xia-ping; Yu, Hai-yan

2007-01-01

Watermelon is a popular fruit in the world with soluble solids content (SSC) being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC detection of watermelons by means of visible/near infrared (Vis/NIR) diffuse transmittance technique. Vis/NIR transmittance spectra of intact watermelons were acquired using a low-cost commercially available spectrometer operating over the range 350~1000 nm. Spectra data were analyz...

Near Infrared Spectral Linearisation in Quantifying Soluble Solids Content of Intact Carambola

Directory of Open Access Journals (Sweden)

Mohd Zubir MatJafri

2013-04-01

Full Text Available This study presents a novel application of near infrared (NIR spectral linearisation for measuring the soluble solids content (SSC of carambola fruits. NIR spectra were measured using reflectance and interactance methods. In this study, only the interactance measurement technique successfully generated a reliable measurement result with a coefficient of determination of (R2 = 0.724 and a root mean square error of prediction for (RMSEP = 0.461° Brix. The results from this technique produced a highly accurate and stable prediction model compared with multiple linear regression techniques.

Near infrared spectral linearisation in quantifying soluble solids content of intact carambola.

Science.gov (United States)

Omar, Ahmad Fairuz; MatJafri, Mohd Zubir

2013-04-12

This study presents a novel application of near infrared (NIR) spectral linearisation for measuring the soluble solids content (SSC) of carambola fruits. NIR spectra were measured using reflectance and interactance methods. In this study, only the interactance measurement technique successfully generated a reliable measurement result with a coefficient of determination of (R2) = 0.724 and a root mean square error of prediction for (RMSEP) = 0.461° Brix. The results from this technique produced a highly accurate and stable prediction model compared with multiple linear regression techniques.

Improving co-amorphous drug formulations by the addition of the highly water soluble amino acid proline

DEFF Research Database (Denmark)

Jensen, Katrine Birgitte Tarp; Löbmann, Korbinian; Rades, Thomas

2014-01-01

Co-amorphous drug amino acid mixtures were previously shown to be a promising approach to create physically stable amorphous systems with the improved dissolution properties of poorly water-soluble drugs. The aim of this work was to expand the co-amorphous drug amino acid mixture approach...... by combining the model drug, naproxen (NAP), with an amino acid to physically stabilize the co-amorphous system (tryptophan, TRP, or arginine, ARG) and a second highly soluble amino acid (proline, PRO) for an additional improvement of the dissolution rate. Co-amorphous drug-amino acid blends were prepared...... the molecular interactions in the form of hydrogen bonds between all three components in the mixture. A salt formation between the acidic drug, NAP, and the basic amino acid, ARG, was found in co-amorphous NAP–ARG. In comparison to crystalline NAP, binary NAP–TRP and NAP–ARG, it could be shown that the highly...

Solubility Enhancement and Formulation of Mouth Dissolving Tablet of Clonazepam with Solid Dispersion Technology

Directory of Open Access Journals (Sweden)

Swati C. Jagdale

2012-01-01

Full Text Available Clonazepam (CLZ is an anticonvulsant benzodiazepine widely used in the treatment of epilepsy. CLZ is a BCS Class II drug and its bioavailability is thus dissolution limited. The objective of the present study was to prepare solid dispersions (SDs of CLZ by various techniques, using the amphiphilic carrier Gelucire 50/13 in various proportions, to increase its water solubility. Drug-polymer interactions were investigated by Fourier-transform infrared (FTIR and UltraViolet (UV spectroscopy. The SDs were characterized physically by differential scanning calorimetry (DSC and X-ray diffraction (XRD. A phase solubility study was performed and the stability constant (Ks was found to be 275.27, while the negative Gibbs free energy (ΔGo tr indicated spontaneous solubilization of the drug. The dissolution study showed that the SDs considerably enhanced the dissolution rate of the drug. The FTIR and UV spectra revealed no chemical incompatibility between the drug and Gelucire 50/13. XRD patterns and the DSC profiles indicated the CLZ was in the amorphous form, which explains the improved dissolution rate of the drug from its SDs. Finally, mouth dissolving tablets (MDTs were prepared from the optimized batches (kneading method of solid dispersion, using crospovidone and Doshion P544 resin as superdisintegrants. The tablets were characterized by in-vitro disintegration and dissolution tests. The study of the MDTs showed disintegration times in the range 32.0±0.85 to 20.0±1.30 sec and dissolution was faster than for the commercial preparation. In conclusion, this investigation demonstrated the potential of solid dispersions of a drug with Gelucire 50/13 for promoting the dissolution of the drug and contributed to the understanding of the effect of a superdisintegrant on mouth dissolving tablets containing a solid dispersion of a hydrophobic drug.

Recovering folic acid and its identification on mixed pastes of tempeh and fermented vegetable as natural source of folic acid

Science.gov (United States)

Susilowati, Agustine; Aspiyanto, Maryati, Yati; Melanie, Hakiki; Lotulung, Puspa D.

2017-11-01

Mixing between tempeh and both fermented broccoli (Brassica oleracea) and spinach (Amaranthus sp.) were conducted to achieve mixed pastes as natural source of folic acid for 'smart food'. Mixing was performed on soy, mung bean, and kidney bean tempehs with both fermented broccoli and spinach at ratio of 1 : 1, 1 : 2, 1 : 3, 1 : 4, 1 : 5 and 1 : 6, respectively. Result of experimental activity showed that pulverizing ratio becoming more and more low will decrease total solids, soluble protein and N-Amino, but fluctuates on folic acid in mixed paste. Based on folic acid equivalent and the best fermented vegetable efficiency, optimization condition was reached in paste with combination between mung beans tempeh and fermented spinach at ratio of 1 : 2 by increasing folic acid concentration of 83.18 % (0.83 times), dissolved protein 432.29 % (4.32 times) and N-amino 55.36 % (0,55 times). While, it is occurred a lowering total solids 22.16 % (0.22 times) when compared with folic acid, soluble protein, N-amino, and total solids on initial materials of mung bean tempeh. In this condition, it is achieved folic acid monomer with molecular weight (MW) 148.14 Da. with relative intensity 100 %, and glutamic acid monomer 443.50 Da.with relative intensity 0.07 %.

Nanosilver and the microbiological activity of the particulate solids versus the leached soluble silver.

Science.gov (United States)

Faiz, Merisa B; Amal, Rose; Marquis, Christopher P; Harry, Elizabeth J; Sotiriou, Georgios A; Rice, Scott A; Gunawan, Cindy

2018-04-01

Nanosilver (Ag NPs) is currently one of the most commercialized antimicrobial nanoparticles with as yet, still unresolved cytotoxicity origins. To date, research efforts have mostly described the antimicrobial contribution from the leaching of soluble silver, while the undissolved solid Ag particulates are often considered as being microbiologically inert, serving only as source of the cytotoxic Ag ions. Here, we show the rapid stimulation of lethal cellular oxidative stress in bacteria by the presence of the undissolved Ag particulates. The cytotoxicity characteristics are distinct from those arising from the leached soluble Ag, the latter being locked in organic complexes. The work also highlights the unique oxidative stress-independent bacterial toxicity of silver salt. Taken together, the findings advocate that future enquiries on the antimicrobial potency and also importantly, the environmental and clinical impact of Ag NPs use, should pay attention to the potential bacterial toxicological responses to the undissolved Ag particulates, rather than just to the leaching of soluble silver. The findings also put into question the common use of silver salt as model material for evaluating bacterial toxicity of Ag NPs.

A Novel Soluble Peptide with pH-Responsive Membrane Insertion.

Science.gov (United States)

Nguyen, Vanessa P; Alves, Daiane S; Scott, Haden L; Davis, Forrest L; Barrera, Francisco N

2015-11-03

Several diseases, such as cancer, are characterized by acidification of the extracellular environment. Acidosis can be employed as a target to specifically direct therapies to the diseased tissue. We have used first principles to design an acidity-triggered rational membrane (ATRAM) peptide with high solubility in solution that is able to interact with lipid membranes in a pH-dependent fashion. Biophysical studies show that the ATRAM peptide binds to the surface of lipid membranes at pH 8.0. However, acidification leads to the peptide inserting into the lipid bilayer as a transmembrane α-helix. The insertion of ATRAM into membranes occurs at a moderately acidic pH (with a pK of 6.5), similar to the extracellular pH found in solid tumors. Studies with human cell lines showed a highly efficient pH-dependent membrane targeting, without causing toxicity. Here we show that it is possible to rationally design a soluble peptide that selectively targets cell membranes in acidic environments.

Major Source of Error in QSPR Prediction of Intrinsic Thermodynamic Solubility of Drugs: Solid vs Nonsolid State Contributions?

Science.gov (United States)

Abramov, Yuriy A

2015-06-01

The main purpose of this study is to define the major limiting factor in the accuracy of the quantitative structure-property relationship (QSPR) models of the thermodynamic intrinsic aqueous solubility of the drug-like compounds. For doing this, the thermodynamic intrinsic aqueous solubility property was suggested to be indirectly "measured" from the contributions of solid state, ΔGfus, and nonsolid state, ΔGmix, properties, which are estimated by the corresponding QSPR models. The QSPR models of ΔGfus and ΔGmix properties were built based on a set of drug-like compounds with available accurate measurements of fusion and thermodynamic solubility properties. For consistency ΔGfus and ΔGmix models were developed using similar algorithms and descriptor sets, and validated against the similar test compounds. Analysis of the relative performances of these two QSPR models clearly demonstrates that it is the solid state contribution which is the limiting factor in the accuracy and predictive power of the QSPR models of the thermodynamic intrinsic solubility. The performed analysis outlines a necessity of development of new descriptor sets for an accurate description of the long-range order (periodicity) phenomenon in the crystalline state. The proposed approach to the analysis of limitations and suggestions for improvement of QSPR-type models may be generalized to other applications in the pharmaceutical industry.

PON-Sol: prediction of effects of amino acid substitutions on protein solubility.

Science.gov (United States)

Yang, Yang; Niroula, Abhishek; Shen, Bairong; Vihinen, Mauno

2016-07-01

Solubility is one of the fundamental protein properties. It is of great interest because of its relevance to protein expression. Reduced solubility and protein aggregation are also associated with many diseases. We collected from literature the largest experimentally verified solubility affecting amino acid substitution (AAS) dataset and used it to train a predictor called PON-Sol. The predictor can distinguish both solubility decreasing and increasing variants from those not affecting solubility. PON-Sol has normalized correct prediction ratio of 0.491 on cross-validation and 0.432 for independent test set. The performance of the method was compared both to solubility and aggregation predictors and found to be superior. PON-Sol can be used for the prediction of effects of disease-related substitutions, effects on heterologous recombinant protein expression and enhanced crystallizability. One application is to investigate effects of all possible AASs in a protein to aid protein engineering. PON-Sol is freely available at http://structure.bmc.lu.se/PON-Sol The training and test data are available at http://structure.bmc.lu.se/VariBench/ponsol.php mauno.vihinen@med.lu.se Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

Science.gov (United States)

Karicheva, E.; Guseva, N.; Kambalina, M.

2016-03-01

Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

Determination of the solubility limiting solid of the selenium in the presence of iron under anoxic conditions

International Nuclear Information System (INIS)

Iida, Y.; Yamaguchi, T.; Tanaka, T.; Kitamura, A.; Nakayama, S.

2009-01-01

Dissolution experiments of selenium were performed from both under saturation and over saturation directions to determine the solubility limiting solid of selenium under the conditions which thermodynamically prefer the formation of ferroselite (FeSe 2 ). X-ray diffractometry (XRD) showed that FeSe 2 was formed in the over-saturation experiments. However, the ion activity products for the reaction of 0.5 FeSe 2 + H + + e - 0.5 Fe 2+ + HSe - , aFe 2+0.5 aHSe - a H+ -1 a e- -1 , obtained from both under saturation and over saturation directions were 3 to 4 orders of magnitude higher than the equilibrium constants calculated from existing thermodynamic data. The dependencies of the selenium concentration on pH, Eh and the iron concentration were better interpreted as a dissolution reaction of selenium solid (Se(s)) than the iron-selenium compounds. The equilibrium constant of: Se(s) + H + + 2e - = HSe - was determined to be logK 0 -7.46±0.11. This value agrees with the value of logK 0 = -7.62±0.06 calculated from existing thermodynamic data of crystalline selenium within errors. Because crystalline selenium was not identified in the solid phases by XRD, the solubility limiting solid would be amorphous or minor amount of crystalline selenium, even if the iron-selenium compound was formed. (authors)

Wax encapsulation of water-soluble compounds for application in foods.

Science.gov (United States)

Mellema, M; Van Benthum, W A J; Boer, B; Von Harras, J; Visser, A

2006-11-01

Water-soluble ingredients have been successfully encapsulated in wax using two preparation techniques. The first technique ('solid preparation') leads to relatively large wax particles. The second technique ('liquid preparation') leads to relatively small wax particles immersed in vegetable oil. On the first technique: stable encapsulation of water-soluble colourants (dissolved at low concentration in water) has been achieved making use of beeswax and PGPR. The leakage from the capsules, for instance of size 2 mm, is about 30% after 16 weeks storage in water at room temperature. To form such capsules a minimum wax mass of 40% relative to the total mass is needed. High amounts of salt or acids at the inside water phase causes more leaking, probably because of the osmotic pressure difference. Osmotic matching of inner and outer phase can lead to a dramatic reduction in leakage. Fat capsules are less suitable to incorporate water soluble colourants. The reason for this could be a difference in crystal structure (fat is less ductile and more brittle). On the second technique: stable encapsulation of water-soluble colourants (encapsulated in solid wax particles) has been achieved making use of carnauba wax. The leakage from the capsules, for instance of size 250 mm, is about 40% after 1 weeks storage in water at room temperature.

Novel furosemide cocrystals and selection of high solubility drug forms.

Science.gov (United States)

Goud, N Rajesh; Gangavaram, Swarupa; Suresh, Kuthuru; Pal, Sharmistha; Manjunatha, Sulur G; Nambiar, Sudhir; Nangia, Ashwini

2012-02-01

Furosemide was screened in cocrystallization experiments with pharmaceutically acceptable coformer molecules to discover cocrystals of improved physicochemical properties, that is high solubility and good stability. Eight novel equimolar cocrystals of furosemide were obtained by liquid-assisted grinding with (i) caffeine, (ii) urea, (iii) p-aminobenzoic acid, (iv) acetamide, (v) nicotinamide, (vi) isonicotinamide, (vii) adenine, and (viii) cytosine. The product crystalline phases were characterized by powder x-ray diffraction, differential scanning calorimetry, infrared, Raman, near IR, and (13) C solid-state NMR spectroscopy. Furosemide-caffeine was characterized as a neutral cocrystal and furosemide-cytosine an ionic salt by single crystal x-ray diffraction. The stability of furosemide-caffeine, furosemide-adenine, and furosemide-cytosine was comparable to the reference drug in 10% ethanol-water slurry; there was no evidence of dissociation of the cocrystal to furosemide for up to 48 h. The other five cocrystals transformed to furosemide within 24 h. The solubility order for the stable forms is furosemide-cytosine > furosemide-adenine > furosemide-caffeine, and their solubilities are approximately 11-, 7-, and 6-fold higher than furosemide. The dissolution rates of furosemide cocrystals were about two times faster than the pure drug. Three novel furosemide compounds of higher solubility and good phase stability were identified in a solid form screen. Copyright © 2011 Wiley Periodicals, Inc.

Significance of excipients to enhance the bioavailability of poorly water-soluble drugs in oral solid dosage forms: A Review

Science.gov (United States)

Vadlamudi, Manoj Kumar; Dhanaraj, Sangeetha

2017-11-01

Nowadays most of the drug substances are coming into the innovation pipeline with poor water solubility. Here, the influence of excipients will play a significant role to improve the dissolution of poorly aqueous soluble compounds. The drug substance needs to be dissolved in gastric fluids to get the better absorption and bioavailability of an orally administered drug. Dissolution is the rate-controlling stage for drugs which controls the rate and degree of absorption. Usually, poorly soluble oral administrated drugs show a slower dissolution rate, inconsistent and incomplete absorption which can lead to lower bioavailability. The low aqueous solubility of BCS class II and IV drugs is a major challenge in the drug development and delivery process. Several technologies have been used in an attempt to progress the bioavailability of poorly water-soluble drug compounds which include solid dispersions, lipid-based formulations, micronization, solvent evaporation, co-precipitation, ordered mixing, liquid-solid compacts, solvent deposition inclusion complexation, and steam aided granulation. In fact, most of the technologies require excipient as a carrier which plays a significant role in improving the bioavailability using Hypromellose acetate succinate, Cyclodextrin, Povidone, Copovidone, Hydroxypropyl cellulose, Hydroxypropyl methylcellulose, Crospovidone, Starch, Dimethylacetamide, Polyethylene glycol, Sodium lauryl sulfate, Polysorbate, Poloxamer. Mesoporous silica and so on. This review deliberates about the excipients significance on bioavailability enhancement of drug products in a single platform along with pragmatically proved applications so that user can able to select the right excipients as per the molecule.

FORMULATION AND EVALUATION OF MEFENAMIC ACID SOLID DISPERSIONS USING PEG-4000

OpenAIRE

Shaik Jamal Shariff; Shaik Saleem; Alaparthi Naga Pavan Kumar; Bachupally Ajay Kumar; Punuru Madhusudhan

2013-01-01

Mefenamic acid (MA) solid Dispersions were prepared employing methanol as a common solvent using PEG-4000 as a drug carrier with two different techniques namely, melting method and solvent evaporation in varied ratios. The prepared solid dispersions were evaluated and compared with that of pure drug (mefenamic acid) in respect to the dissolution rate and dissolution efficiency. It is noted that solid dispersions of mefenamic acid showed a remarkable increase in dissolution rate and dissolutio...

The solubilities of significant organic compounds in HLW tank supernate solutions

International Nuclear Information System (INIS)

Barney, G.S.

1994-08-01

Large quantities of organic chemicals used in reprocessing spent nuclear-fuels at the Hanford Site have accumulated in underground high-level radioactive waste tanks. The organic content of these tanks must he known so that the potential for hazardous reactions between organic components and sodium nitrate/nitrite salts in the waste can he evaluated. The solubilities of organic compounds described in this report will help determine if they are present in the solid phases (salt cake and sludges) as well as the liquid phase (interstitial liquor/supernate) in the tanks. The solubilities of five significant sodium salts of carboxylic acids and aminocarboxylic acids [sodium oxalate, formate, citrate, nitrilotriacetate (NTA) and ethylendiaminetetraacetate (EDTA)] were measured in a simulated supernate solution at 25 degrees C, 30 degrees C, 40 degrees C, and 50 degrees C

Separation of three water-soluble vitamins by poly(dimethylsiloxane) microchannel electrophoresis with electrochemical detection.

Science.gov (United States)

Li, Xiang-Yun; Zhang, Qian-Li; Lian, Hong-Zhen; Xu, Jing-Juan; Chen, Hong-Yuan

2007-09-01

A method for rapid separation and sensitive determination of three water-soluble vitamins, pyridoxine, ascorbic acid (VC), and p-aminobenzoic acid (PABA) has been developed by PDMS microchannel electrophoresis integrated with amperometric detection. After treatment of the microchip with oxygen plasma, the peak shapes of the three analytes were essentially improved. Pyridoxine, VC, and PABA were well separated within only 80 s in a running buffer of 20 mM borate solution (pH 8.5). Good linearity was obtained within the concentration range of 2-200 microM for the three water-soluble vitamins. The detection limits were 1.0 microM for pyridoxine and VC, and 1.5 microM for PABA. The proposed method has been successfully applied to real human urine sample, without solid phase extraction, with recoveries of 80-122% for the three water-soluble vitamins.

Improving the water solubility of Monascus pigments under acidic conditions with gum arabic.

Science.gov (United States)

Jian, Wenjie; Sun, Yuanming; Wu, Jian-Yong

2017-07-01

Monascus pigments (Mps) are natural food colorants and their stability in acidic solutions is important for application in the food industry. This study aimed to evaluate the use of gum arabic (GA) as a stabilizer for maintaining the solubility of Mps in an acidic aqueous solution exposed to a high temperature, and to analyze the molecular interactions between GA and Mps. Mps dispersed (0.2 g kg -1 ) in deionized water at pH 3.0-4.0 without GA formed precipitates but remained in a stable solution in the presence of GA (1 g kg -1 ). The significant improvement of Mps water solubility under acidic conditions was attributed to the formation of Mps-GA complexes, as indicated by a sharp increase in the fluorescence intensity. The results on particle size, zeta potential, and transmission electron microscopy further suggested that molecular binding of Mps to GA, electrostatic repulsion, and steric hindrance of GA were contributing factors to preventing the aggregation of Mps in acidic solutions. A mechanistic model was presented for GA-Mps interactions and complex structures. GA was proven to be an effective stabilizer of natural food colorants in acidic solutions. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Synthesis of acid-soluble spore proteins by Bacillus subtilis.

OpenAIRE

Leventhal, J M; Chambliss, G H

1982-01-01

The major acid-soluble spore proteins (ASSPs) of Bacillus subtilis were detected by immunoprecipitation of radioactively labeled in vitro- and in vivo-synthesized proteins. ASSP synthesis in vivo began 2 h after the initiation of sporulation (t2) and reached its maximum rate at t7. This corresponded to the time of synthesis of mRNA that stimulated the maximum rate of ASSP synthesis in vitro. Under the set of conditions used in these experiments, protease synthesis began near t0, alkaline phos...

Cocrystals of a 1,2,4-thiadiazole-based potent neuroprotector with gallic acid: solubility, thermodynamic stability relationships and formation pathways.

Science.gov (United States)

Surov, Artem O; Churakov, Andrei V; Proshin, Alexey N; Dai, Xia-Lin; Lu, Tongbu; Perlovich, German L

2018-05-30

Three distinct solid forms, namely anhydrous cocrystals with 2 : 1 and 1 : 1 drug/acid ratios ([TDZ : GA] (2 : 1), [TDZ : GA] (1 : 1)), and a hydrated one having 1 : 1 : 1 drug/acid/water stoichiometry ([TDZ : GA : H2O] (1 : 1 : 1)), have been formed by cocrystallization of the biologically active 1,2,4-thiadiazole derivative (TDZ) with gallic acid (GA). The thermodynamic stability relationships between the cocrystals were rationalized in terms of Gibbs energies of the formation reactions and further verified by performing a set of competitive and exchange mechanochemical reactions. Interestingly, competitive grinding in the presence of the structurally related vanillic acid led to the formation of a new polymorphic form of the [TDZ : Vanillic acid] (1 : 1) cocrystal, which was promoted by gallic acid. The mechanochemical method was also applied to elucidate the alternative pathways of the [TDZ : GA : H2O] (1 : 1 : 1) cocrystal formation. Direct cocrystallization of TDZ with GA monohydrate was found to proceed much faster than the reaction of TDZ and anhydrous GA in the presence of an acetonitrile/water mixture, which may indicate the presence of a transitional stage. According to dissolution studies, the [TDZ : GA : H2O] (1 : 1 : 1) cocrystal was ca. 6.6 times more soluble than the parent 1,2,4-thiadiazole at pH 2.0 and 25.0 °C. The apparent two-step dehydration behavior of the [TDZ : GA : H2O] (1 : 1 : 1) cocrystal monohydrate was clarified by analyzing the intermolecular interactions of water molecules with the crystalline environment derived from solid state DFT calculations.

Identification of water-soluble heavy crude oil organic-acids, bases, and neutrals by electrospray ionization and field desorption ionization fourier transform ion cyclotron resonance mass spectrometry.

Science.gov (United States)

Stanford, Lateefah A; Kim, Sunghwan; Klein, Geoffrey C; Smith, Donald F; Rodgers, Ryan P; Marshall, Alan G

2007-04-15

We identify water-soluble (23 degrees C) crude oil NSO nonvolatile acidic, basic, and neutral crude oil hydrocarbons by negative-ion ESI and continuous flow FD FT-ICR MS at an average mass resolving power, m/deltam50% = 550,000. Of the 7000+ singly charged acidic species identified in South American crude oil, surprisingly, many are water-soluble, and much more so in pure water than in seawater. The truncated m/z distributions for water-soluble components exhibit preferential molecular weight, size, and heteroatom class influences on hydrocarbon solubility. Acidic water-soluble heteroatomic classes detected at >1% relative abundance include O, O2, O3, O4, OS, O2S, O3S, O4S, NO2, NO3, and NO4. Parent oil class abundance does not directly relate to abundance in the water-soluble fraction. Acidic oxygen-containing classes are most prevalent in the water-solubles, whereas acidic nitrogen-containing species are least soluble. In contrast to acidic nitrogen-containing heteroatomic classes, basic nitrogen classes are water-soluble. Water-soluble heteroatomic basic classes detected at >1% relative abundance include N, NO, NO2, NS, NS2, NOS, NO2S, N2, N2O, N2O2, OS, O2S, and O2S2.

Chemical constituents: water-soluble vitamins, free amino acids and sugar profile from Ganoderma adspersum.

Science.gov (United States)

Kıvrak, İbrahim

2015-01-01

Ganoderma adspersum presents a rigid fruiting body owing to chitin content and having a small quantity of water or moisture. The utility of bioactive constituent of the mushroom can only be available by extraction for human usage. In this study, carbohydrate, water-soluble vitamin compositions and amino acid contents were determined in G. adspersum mushroom. The composition in individual sugars was determined by HPLC-RID, mannitol (13.04 g/100 g) and trehalose (10.27 g/100 g) being the most abundant sugars. The examination of water-soluble vitamins and free amino acid composition was determined by UPLC-ESI-MS/MS. Essential amino acid constituted 67.79% of total amino acid, which is well worth the attention with regard to researchers and consumers. In addition, G. adspersum, which is also significantly rich in B group vitamins and vitamin C, can provide a wide range of notable applications in the pharmaceutics, cosmetics, food and dietary supplement industries. G. adspersum revealed its value for pharmacy and nutrition fields.

Solubility measurement of iron-selenium compounds under reducing conditions. Research document

International Nuclear Information System (INIS)

Kitamura, Akira; Shibata, Masahiro

2003-03-01

Chemical behavior of selenium (Se), which was one of the important elements for performance assessment of geological disposal of high-level radioactive waste, was investigated under reducing and iron-containing conditions. A washing method for an iron diselenide (FeSe 2 (cr)) reagent with acidic and basic solutions (0.1 and 1 M HCl and 1 M NaOH) was carried out for the purification of FeSe 2 reagent, which was considered to be a solubility limiting solid for Se under the geological disposal conditions. Furthermore, solubility of FeSe 2 (cr) was measured in alkaline solution (pH: 11 - 13) under reducing conditions (E h vs SHE: -0.4 - 0 V), and thermodynamic data on equilibrium reactions between Se in solution and Se precipitate were obtained. The dependencies of solubility values on pH and redox potential (E h : vs. standard hydrogen electrode) were best interpreted that the solubility limiting solid was not FeSe 2 (cr) but Se(cr) and the aqueous species was SeO 3 2- in the present experimental conditions. The equilibrium constant between Se(cr) and SeO 3 2- at zero ionic strength was determined and compared with literature values. The chemical behavior of Se under geological disposal conditions was discussed. (author)

Solubility of heavy metals added to MSW

International Nuclear Information System (INIS)

Lo, H.M.; Lin, K.C.; Liu, M.H.; Pai, T.Z.; Lin, C.Y.; Liu, W.F.; Fang, G.C.; Lu, C.; Chiang, C.F.; Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C.

2009-01-01

This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO 3 and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K d (l g -1 ) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K d (l g -1 ) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions

Solubility of heavy metals added to MSW

Energy Technology Data Exchange (ETDEWEB)

Lo, H.M. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)], E-mail: hmlo@cyut.edu.tw; Lin, K.C. [Department of Occupational Safety and Health, Chung Shan Medical University, 110, Sec. 1, Jiangguo N. Rd., Taichung 402, Taiwan (China); Liu, M.H.; Pai, T.Z. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China); Lin, C.Y. [Department of Soil and Water Conservation, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Liu, W.F. [Department of Electronical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 407, Taiwan (China); Fang, G.C. [Department of Environmental Engineering, Hungkuang University, 34 Chung-Chie Road, Sha Lu, Taichung 433, Taiwan (China); Lu, C. [Department of Environmental Engineering, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Chiang, C.F. [Department of Health Risk Management, China Medical University, No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan (China); Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)

2009-01-15

This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO{sub 3} and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K{sub d} (l g{sup -1}) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K{sub d} (l g{sup -1}) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions.

Solid dispersions of Myricetin with enhanced solubility: Formulation, characterization and crystal structure of stability-impeding Myricetin monohydrate crystals

Science.gov (United States)

Mureşan-Pop, M.; Pop, M. M.; Borodi, G.; Todea, M.; Nagy-Simon, T.; Simon, S.

2017-08-01

Three solid dispersion forms of Myricetin combined with the Polyvinylpyrrolidone were successfully prepared by spray drying method, and characterized by X-ray powder diffraction, thermal analysis, infrared spectroscopy and optical microscopy. Zeta potential measurements provided indications on solid dispersions stability in aqueous suspension related to their storage at elevated temperature and relative humidity, which depends on the Myricetin load. By increase of Myricetin load, the stability of the solid dispersion is impeded due to growth of Myricetin monohydrate crystals. The amorphous dispersions with 10% and 50% Myricetin load are stable and, compared to pure Myricetin, their aqueous solubility is enhanced by a factor of 47 and 13, respectively. The dispersion with 80% Myricetin load is unstable on storage, and this behavior acts in conjunction with the development of Myricetin monohydrate crystals. Single-crystal X-ray diffraction results obtained for Myricetin monohydrate reveal a structure of an infinite 2D network of hydrogen-bonded molecules involving all six hydroxyl groups of Myricetin. The water molecules are positioned in between the infinite chains, and contribute via H-bonds to robust crystal packing. The calculated needle-like morphology of monohydrate form is in agreement with the optical microscopy results. The study shows that the solid amorphous dispersions with up to 50% Myricetin load are a viable option for achieving substantial solubility improvement of Myricetin, and supports their potential use in pharmaceutical applications.

Redox potentials and kinetics of the Ce 3+/Ce 4+ redox reaction and solubility of cerium sulfates in sulfuric acid solutions

Science.gov (United States)

Paulenova, A.; Creager, S. E.; Navratil, J. D.; Wei, Y.

Experimental work was performed with the aim of evaluating the Ce 4+/Ce 3+ redox couple in sulfuric acid electrolyte for use in redox flow battery (RFB) technology. The solubility of cerium sulfates in 0.1-4.0 M sulfuric acid at 20-60 °C was studied. A synergistic effect of both sulfuric acid concentration and temperature on the solubility of cerous sulfate was observed. The solubility of cerous sulfate significantly decreased with rising concentration of sulfuric acid and rising temperature, while the solubility of ceric sulfate goes through a significant maximum at 40 °C. Redox potentials and the kinetics of the cerous/ceric redox reaction were also studied under the same temperature-concentration conditions. The redox potentials were measured using the combined redox electrode (Pt-Ag/AgCl) in equimolar Ce 4+/Ce 3+ solutions (i.e.[Ce 3+]=[Ce 4+]) in sulfuric acid electrolyte. The Ce 3+/Ce 4+ redox potentials significantly decrease (i.e. shift to more negative values) with rising sulfuric acid concentration; a small maximum is observed at 40 °C. Cyclic voltammetric experiments confirmed slow electrochemical kinetics of the Ce 3+/Ce 4+ redox reaction on carbon glassy electrodes (CGEs) in sulfuric acid solutions. The observed dependencies of solubilities, the redox potentials and the kinetics of Ce 3+/Ce 4+ redox reaction on sulfuric acid concentration are thought to be the result of inequivalent complexation of the two redox species by sulfate anions: the ceric ion is much more strongly bound to sulfate than is the cerous ion. The best temperature-concentration conditions for the RFB electrolytes appear to be 40 °C and 1 M sulfuric acid, where the relatively good solubility of both cerium species, the maximum of redox potentials, and the more or less satisfying stability of CGE s were found. Even so, the relatively low solubility of cerium salts in sulfuric acid media and slow redox kinetics of the Ce 3+/Ce 4+ redox reaction at carbon indicate that the Ce 3+/Ce

Hemicellulose hydrolysis catalysed by solid acids

NARCIS (Netherlands)

Carà, P.D.; Pagliaro, M.; Elmekawy, A.; Brown, D.R.; Verschuren, P.; Shiju, N.R.; Rothenberg, G.

2013-01-01

Depolymerising hemicellulose into platform sugar molecules is a key step in developing the concept of an integrated biorefinery. This reaction is traditionally catalysed by either enzymes or homogeneous mineral acids. We compared various solid catalysts for hemicellulose hydrolysis, running

Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate; Lixiviacion de concentrados de cobre utilizando NaCl y el cobre soluble aportado por el propio concentrado

Energy Technology Data Exchange (ETDEWEB)

Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

2005-07-01

Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs.

pH-metric solubility. 2: correlation between the acid-base titration and the saturation shake-flask solubility-pH methods.

Science.gov (United States)

Avdeef, A; Berger, C M; Brownell, C

2000-01-01

The objective of this study was to compare the results of a normal saturation shake-flask method to a new potentiometric acid-base titration method for determining the intrinsic solubility and the solubility-pH profiles of ionizable molecules, and to report the solubility constants determined by the latter technique. The solubility-pH profiles of twelve generic drugs (atenolol, diclofenac.Na, famotidine, flurbiprofen, furosemide, hydrochlorothiazide, ibuprofen, ketoprofen, labetolol.HCl, naproxen, phenytoin, and propranolol.HCl), with solubilities spanning over six orders of magnitude, were determined both by the new pH-metric method and by a traditional approach (24 hr shaking of saturated solutions, followed by filtration, then HPLC assaying with UV detection). The 212 separate saturation shake-flask solubility measurements and those derived from 65 potentiometric titrations agreed well. The analysis produced the correlation equation: log(1/S)titration = -0.063(+/- 0.032) + 1.025(+/- 0.011) log(1/S)shake-flask, s = 0.20, r2 = 0.978. The potentiometrically-derived intrinsic solubilities of the drugs were: atenolol 13.5 mg/mL, diclofenac.Na 0.82 microg/mL, famotidine 1.1 mg/ mL, flurbiprofen 10.6 microg/mL, furosemide 5.9 microg/mL, hydrochlorothiazide 0.70 mg/mL, ibuprofen 49 microg/mL, ketoprofen 118 microg/mL, labetolol.HCl 128 microg/mL, naproxen 14 microg/mL, phenytoin 19 microg/mL, and propranolol.HCl 70 microg/mL. The new potentiometric method was shown to be reliable for determining the solubility-pH profiles of uncharged ionizable drug substances. Its speed compared to conventional equilibrium measurements, its sound theoretical basis, its ability to generate the full solubility-pH profile from a single titration, and its dynamic range (currently estimated to be seven orders of magnitude) make the new pH-metric method an attractive addition to traditional approaches used by preformulation and development scientists. It may be useful even to discovery

Solid solubility, phase transitions, thermal expansion, and compressibility in Sc{sub 1−x}Al{sub x}F{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Morelock, Cody R.; Gallington, Leighanne C. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Wilkinson, Angus P., E-mail: angus.wilkinson@chemistry.gatech.edu [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)

2015-02-15

With the goal of thermal expansion control, the synthesis and properties of Sc{sub 1−x}Al{sub x}F{sub 3} were investigated. The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. Solid solutions (x≤0.50) were characterized by synchrotron powder diffraction at ambient pressure between 100 and 900 K and at pressures <0.414 GPa while heating from 298 to 523 K. A phase transition from cubic to rhombohedral is observed. The transition temperature increases smoothly with Al{sup 3+} content, approaching 500 K at the solid solubility limit, and also upon compression at fixed Al{sup 3+} content. The slope of the pressure–temperature phase boundary is ∼0.5 K MPa{sup −1}, which is steep relative to that for most symmetry-lowering phase transitions in perovskites. The volume coefficient of thermal expansion (CTE) for the rhombohedral phase is strongly positive, but the cubic-phase CTE varies from negative (x<0.15) to near-zero (x=0.15) to positive (x>0.20) between ∼600 and 800 K. The cubic solid solutions elastically stiffen on heating, while Al{sup 3+} substitution causes softening at a given temperature. - Graphical abstract: The cubic-phase coefficient of thermal expansion for Sc{sub 1−x}Al{sub x}F{sub 3}(solubility limit ∼50% at ∼1340 K) becomes more positive with increased Al{sup 3+} substitution, but the average isothermal bulk modulus decreases (elastic softening). - Highlights: • The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. • The phase transition temperature of Sc{sub 1−x}Al{sub x}F{sub 3} increases smoothly with x. • The cubic-phase volume CTE varies from negative to positive with increasing x. • The cubic solid solutions elastically stiffen on heating. • Al{sup 3+} substitution causes softening at a given temperature.

Stability constants and solubility of neptunium and plutonium complexes with alkylphosphoric acids in TBP

International Nuclear Information System (INIS)

Fedoseev, D.A.; Romanovskaya, I.A.; Artemova, L.A.; Gubina, M.Yu.

1988-01-01

Stability concetration constants K and solubility of neptunium and plutonium complexes with di- and monobuthylphosphoric acids (APC) and with orthophosphoric and di-2-ethylhexyl-phosphoric acids in 30% TBP solution-n-dodecane system are determined by spectrophotometric titration and radiometry methods. Posibility of forecasting radiation-chemical behaviour of actinids according to data on K and APC radiation-chemical yield values is demonstrated

Preparation of free, soluble conjugate, and insoluble-bound phenolic compounds from peels of rambutan (Nephelium lappaceum) and evaluation of antioxidant activities in vitro.

Science.gov (United States)

Sun, Liping; Zhang, Huilin; Zhuang, Yongliang

2012-02-01

The soluble phenolic compounds of rambutan peels (RP) were extracted by microwave-assisted extraction (MAE) and the operating parameters were optimized. The optimal conditions obtained were ethanol concentration of 80.85%, extraction time of 58.39 s, and the ratio of liquid to solid of 24.51:1. The soluble phenolic content by MAE was 213.76 mg GAE/g DW. The free, soluble conjugate, and insoluble-boaund phenolic compounds were prepared by alkaline hydrolysis, and the contents of 3 fractions were 185.12, 27.98 and 9.37 mg GAE/g DW, respectively. The contents of syringic acid and p-coumaric acid were high in the free fraction, showing 16.86 and 19.44 mg/g DW, and the soluble conjugate and insoluble-bound phenolics were mainly composed of gallic acid and caffeic acid. Furthermore, the antioxidant activities of 3 fractions were evaluated in 5 model systems. Results indicated that the free fraction had high antioxidant activities, compared with the soluble conjugate and insoluble-bound fractions. © 2012 Institute of Food Technologists®

Solubility-pH profiles of some acidic, basic and amphoteric drugs.

Science.gov (United States)

Shoghi, Elham; Fuguet, Elisabet; Bosch, Elisabeth; Ràfols, Clara

2013-01-23

The solubility vs. pH profiles of five ionizable drugs of different nature (a monoprotic acid, a monoprotic base, a diprotic base and two amphoteric compounds showing a zwitterionic species each one) have been determined through two different methodologies: the classical shake-flask (S-F) and the potentiometric Cheqsol methods using in both instances the appropriate Henderson-Hasselbalch (H-H) or derived relationships. The results obtained independently from both approaches are consistent. A critical revision about the influence of the electrolyte used as buffering agent in the S-F method on the obtained solubility values is also performed. Thus, some deviations of the experimental points with respect the H-H profiles can be attributed to specific interactions between the buffering electrolyte and the drug due to the hydrotrophic character of citric and lactic acids. In other cases, the observed deviations are independent of the buffers used since they are caused by the formation of new species such as drug aggregates (cefadroxil) or the precipitation of a salt from a cationic species of the analyzed compound (quetiapine). Copyright © 2012 Elsevier B.V. All rights reserved.

Determining a Solubility Product Constant by Potentiometric Titration to Increase Students' Conceptual Understanding of Potentiometry and Titrations

Science.gov (United States)

Grabowski, Lauren E.; Goode, Scott R.

2017-01-01

Potentiometric titrations are widely taught in first-year undergraduate courses to connect electrochemistry, stoichiometry, and equilibria and to reinforce acid-base titrations. Students perform a potentiometric titration that is then analyzed to determine analyte concentrations and the solubility product constant of the solid species.

Rheology of dilute acid hydrolyzed corn stover at high solids concentration.

Science.gov (United States)

Ehrhardt, M R; Monz, T O; Root, T W; Connelly, R K; Scott, C T; Klingenberg, D J

2010-02-01

The rheological properties of acid hydrolyzed corn stover at high solids concentration (20-35 wt.%) were investigated using torque rheometry. These materials are yield stress fluids whose rheological properties can be well represented by the Bingham model. Yield stresses increase with increasing solids concentration and decrease with increasing hydrolysis reaction temperature, acid concentration, and rheometer temperature. Plastic viscosities increase with increasing solids concentration and tend to decrease with increasing reaction temperature and acid concentration. The solids concentration dependence of the yield stress is consistent with that reported for other fibrous systems. The changes in yield stress with reaction conditions are consistent with observed changes in particle size. This study illustrates that torque rheometry can be used effectively to measure rheological properties of concentrated biomass.

Effects of Gibberellic Acid and Putrescine Treatments on Marketable and Some Quality Attributes Certains of Citrus Fruit (Citrus sinensis Cv. Hamlen

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H. Azh

2014-04-01

Full Text Available Citrus fruit quality preserve the post harvest cause marketability increased. In this research, the effect of putrescin and gibberellic acid concentrations on storage life of sweet orange fruit (Hamlen cultivar was studied to in factorial design (3*3*6=54based on randomized complete block with six replications. Putrescin at three concentrations( 0, 1 and 2 mM and three level of gibberellic acid (0, 50 and 100 mg/L were sprayed on the tree at the physiological maturation stage and two weeks pre harvest. Fruit firmness, marketability, vitamin C, total acidity, total soluble solids (TSS and ratio of total soluble solids (TSS to total acidity were evaluated. The results showed that putrescin spraying at 1 mM significantly prevented fruit softening and preserved fruit firmness. Also putrescin treatment (1 mM preserved ideal marketability and was superior than other treatments. Gibberellic acid significantly preserved total acidity and total soluble solids. The interaction of gibberellic acid and putrescine also preserved significantly vitamin C. Therefore, the application of putrescine at 1 mM and gibberellic at 100 mg/L was recommended for preserve marketability, appearance and quality of citrus sinensis cv. Hamlen.

Solubility of Nd in brine

International Nuclear Information System (INIS)

Khalili, F.I.; Symeopoulos, V.; Chen, J.F.; Choppin, G.R.

1994-01-01

The solubility of Nd(III) has been measured at 23±3 C in a synthetic brine at pcH 6.4, 8.4, 10.4 and 12.4. The brine consisted predominantly of (Na+K)Cl and MgCl 2 with an ionic strength of 7.8 M (9.4 m) a solid compound of Nd(III) at each pcH was assigned from X-ray diffraction patterns. The log values of the experimental solubilities decrease fomr -3 at pcH 6.4 to -5.8 at pcH 8.4; at pcH 10.4 and 12.4 the solubility was below the detection limit of -7.5. The experimental solubility does not follow closely the variation with pcH estimated from modeling of the species in solution in equilibrium with the Nd solid using S.I.T. (orig.)

Assessment of hupu gum for its carrier property in the design and evaluation of solid mixtures of poorly water soluble drug - rofecoxib.

Science.gov (United States)

Vadlamudi, Harini Chowdary; Raju, Y Prasanna; Asuntha, G; Nair, Rahul; Murthy, K V Ramana; Vulava, Jayasri

2014-01-01

There are no reports about the pharmaceutical applications of hupu gum (HG). Hence the present study was undertaken to test its suitability in the dissolution enhancement of poorly water soluble drug. Rofecoxib (RFB) was taken as model drug. For comparison solid mixtures were prepared with carriers such as poly vinyl pyrrolidone (PVP), sodium starch glycollate (SSG) and guar gum (GG). Physical mixing (PM), co-grinding (CG), kneading (KT) and solvent evaporation (SE) techniques were used to prepare the solid mixtures, using all the carriers in different carrier and drug ratios. The solid mixtures were characterized by powder X-ray diffraction (XRD) and Fourier-transformed infrared spectroscopy (FTIR). There was a significant improvement in the dissolution rate of solid mixtures of HG, when compared with the solid mixtures of other carriers. There was an increase in dissolution rate with increase in concentration of HG upto 1:1 ratio of carrier and drug. No drug-carrier interaction was found by FTIR studies. XRD studies indicated reduction in crystallinity of the drug with increase in HG concentration. Hence HG could be a useful carrier for the dissolution enhancement of poorly water soluble drugs.

Dual Activity of Hydroxypropyl-β-Cyclodextrin and Water-Soluble Carriers on the Solubility of Carvedilol.

Science.gov (United States)

Zoghbi, Abdelmoumin; Geng, Tianjiao; Wang, Bo

2017-11-01

Carvedilol (CAR) is a non-selective α and β blocker categorized as class II drug with low water solubility. Several recent studies have investigated ways to overcome this problem. The aim of the present study was to combine two of these methods: the inclusion complex using hydroxypropyl-β-cyclodextrin (HPβCD) with solid dispersion using two carriers: Poloxamer 188 (PLX) and Polyvinylpyrrolidone K-30 (PVP) to enhance the solubility, bioavailability, and the stability of CAR. Kneading method was used to prepare CAR-HPβCD inclusion complex (KD). The action of different carriers separately and in combination on Carvedilol solubility was investigated in three series. CAR-carrier and KD-carrier solid dispersions were prepared by solvent evaporation method. In vitro dissolution test was conducted in three different media: double-distilled water (DDW), simulative gastric fluid (SGF), and PBS pH 6.8 (PBS). The interactions between CAR, HPβCD, and different carriers were explored by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), and differential scanning colorimetry (DSC). The results showed higher solubility of CAR in KD-PVP solid dispersions up to 70, 25, and 22 fold compared to pure CAR in DDW, SGF, and PBS, respectively. DSC and XRD analyses indicated an improved degree of transformation of CAR in KD-PVP solid dispersion from crystalline to amorphous state. This study provides a new successful combination of two polymers with the dual action of HPβCD and PLX/PVP on water solubility and bioavailability of CAR.

Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1

DEFF Research Database (Denmark)

Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka

2013-01-01

molecular weight excipients that form specific molecular interactions with the drug resulting in co-amorphous forms. The two poorly water soluble drugs carbamazepine and indomethacin were combined with amino acids from the binding sites of the biological receptors of these drugs. Mixtures of drug...

Solid-phase route to Fmoc-protected cationic amino acid building blocks

DEFF Research Database (Denmark)

Clausen, Jacob Dahlqvist; Linderoth, Lars; Nielsen, Hanne Mørck

2012-01-01

Diamino acids are commonly found in bioactive compounds, yet only few are commercially available as building blocks for solid-phase peptide synthesis. In the present work a convenient, inexpensive route to multiple-charged amino acid building blocks with varying degree of hydrophobicity...... was developed. A versatile solid-phase protocol leading to selectively protected amino alcohol intermediates was followed by oxidation to yield the desired di- or polycationic amino acid building blocks in gram-scale amounts. The synthetic sequence comprises loading of (S)-1-(p-nosyl)aziridine-2-methanol onto...... of simple neutral amino acids as well as analogs displaying high bulkiness or polycationic side chains was prepared. Two building blocks were incorporated into peptide sequences using microwave-assisted solid-phase peptide synthesis confirming their general utility....

Diesel-soluble lignin oils and methods of their production

DEFF Research Database (Denmark)

2016-01-01

Solvent consumption in supercritical ethanol, propanol or butanol treatment of either refined pre-extracted lignin or comparatively impure lignin-rich solid residual from hydrothermally pretreated lignocellulosic biomass can be minimized by conducting the reaction at very high loading of lignin...... to solvent. Comparatively impure, crude lignin- rich solid residual can be directly converted by supercritical alcohol treatment to significantly diesel-soluble lignin oil without requirement for pre-extraction or pre- solubilisation of lignin or for added reaction promoters such as catalysts, hydrogen donor...... co-solvents, acids, based or H2 gas. O:C ratio of product oil can readily be obtained using crude lignin residual in such a process at levels 0.20 or lower....

Thermodynamic data development using the solubility method (Joint research)

International Nuclear Information System (INIS)

Rai, Dhanpat; Yui, Mikazu

2013-05-01

The solubility method is one of the most powerful tools to obtain reliable thermodynamic data for 1) solubility products of discrete solids and double salts, 2) complexation constants for various ligands, 3) development of data in a wide range of pH values, 4) evaluation of data for metals that form very insoluble solids (e.g. tetravalent actinides), 5) determining solubility-controlling solids in different types of wastes and 6) elevated temperatures for redox sensitive systems. This document is focused on describing various aspects of obtaining thermodynamic data using the solubility method. This manuscript deals with various aspects of conducting solubility studies, including selecting the study topic, modeling to define important variables, selecting the range of variables and experimental parameters, anticipating results, general equipment requirements, conducting experiments, and interpreting experimental data. (author)

Effect of Difference in Fatty Acid Chain Lengths of Medium- Chain Lipids on Lipid/Surfactant/Water Phase Diagrams and Drug Solubility

Directory of Open Access Journals (Sweden)

Hetal N. Prajapati

2011-09-01

Full Text Available Lipids consisting of medium chain fatty acids are commonly used in the development of lipid-based selfemulsifying and self-microemulsifying drug delivery systems. However, no systematic approach to selecting one lipid over another has been reported in the literature. In this study, propylene glycol (PG monoester (PG monocaprylate, Capmul PG-8® and PG diester (PG dicaprylocaprate, Captex 200P® of C8-fatty acids were compared with PG monoester (PG monolaurate, Capmul PG-12® and PG diester (PG dilaurate, Capmul PG-2L® of C12-fatty acids with respect to their phase diagrams, and especially for their ability to form microemulsions in the presence of a common surfactant, Cremophor EL®, and water. The solubility of two model drugs, danazol and probucol, in the lipids and lipid/surfactant mixtures were also compared. The effect of the chain length of medium-chain fatty acids (C8 versus C12 on the phase diagrams of the lipids was minimal. Both shorter and longer chain lipids formed essentially similar microemulsion and emulsion regions in the presence of Cremophor EL® and water, although the C12-fatty acid esters formed larger gel regions in the phase diagrams than the C8-fatty acid esters. When monoesters were mixed with their respective diesters at 1:1 ratios, larger microemulsion regions with lower lipid particle sizes were observed compared to those obtained with individual lipids alone. While the solubility of both danazol and probucol increased greatly in all lipids studied, compared to their aqueous solubility, the solubility in C12-fatty acid esters was found to be lower than in C8-fatty acid esters when the lipids were used alone. This difference in solubility due to the difference in fatty acid chain length, practically disappeared when the lipids were combined with the surfactant.

Fermentation of calcium-fortified soymilk with Lactobacillus: effects on calcium solubility, isoflavone conversion, and production of organic acids.

Science.gov (United States)

Tang, A L; Shah, N P; Wilcox, G; Walker, K Z; Stojanovska, L

2007-11-01

The objective of this study was to enhance calcium solubility and bioavailability from calcium-fortified soymilk by fermentation with 7 strains of Lactobacillus, namely, L. acidophilus ATCC 4962, ATCC33200, ATCC 4356, ATCC 4461, L. casei ASCC 290, L. plantarum ASCC 276, and L. fermentum VRI-003. The parameters that were used are viability, pH, calcium solubility, organic acid, and biologically active isoflavone aglycone content. Calcium-fortified soymilk made from soy protein isolate was inoculated with these probiotic strains, incubated for 24 h at 37 degrees C, then stored for 14 d at 4 degrees C. Soluble calcium was measured using atomic absorption spectrophotometry (AA). Organic acids and bioactive isoflavone aglycones, including diadzein, genistein, and glycetein, were measured using HPLC. Viability of the strains in the fermented calcium-fortified soymilk was > 8.5 log(10) CFU/g after 24 h fermentation and this was maintained for 14-d storage at 4 degrees C. After 24 h, there was a significant increase (P casei ASCC 290 demonstrated the highest increase with 89.3% and 87.0% soluble calcium after 24 h, respectively. The increase in calcium solubility observed was related to lowered pH associated with production of lactic and acetic acids. Fermentation significantly increased (P < 0.05) the level of conversion of isoflavones into biologically active aglycones, including diadzein, genistein, and glycetein. Our results show that fermenting calcium-fortified soymilk with the selected probiotics can potentially enhance the calcium bioavailability of calcium-fortified soymilk due to increased calcium solubility and bioactive isoflavone aglycone enrichment.

The dynamics of acid-soluble phosphorus compounds in the course of winter and spring wheat germination under various thermic conditions. Part II. Labile phosphorus after hydrolysis of the acid-soluble fraction

Directory of Open Access Journals (Sweden)

A. Barbaro

2015-06-01

Full Text Available The changes in labile phosphorus compounds content during germination of wheat were investigated. These compounds were determined in acid-soluble germ extracts separated into fractions according to the solubility of their barium salts. Low germination temperature was found to raise the labile phosphorus content in the fraction of insoluble barium salts. If we assume that labile P of this fraction consisted mainly of adenosinedi- and triphosphates, it would seem that the rise, in the ATP and ADP level under the influence of low temperature may be essential for initiating flowering in winter varieties.

Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate

International Nuclear Information System (INIS)

Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

2005-01-01

Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs

Effectiveness of anchovy substrate application on decreasing acid solubility of Sprague Dawley rats’ tooth enamel (in vivo)

Science.gov (United States)

Triputra, F.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis), a natural resource of Indonesia, contain fluoride in the form of CaF2 and can function as a fluoridation material to prevent dental caries. The aim of this study is to study the effectiveness of anchovy substrate, through food or topical application, in decreasing the acid solubility of tooth enamel. This research used 14 Sprague Dawley rats as subjects divided into the following 5 groups: baseline, experimental feeding, experimental smearing, and their negative controls. After 15 days of anchovy substrate application, lower incisors were extracted and the acid solubility of enamel was analyzed qualitatively and quantitatively using a stereo microscope and a Micro-Vickers Hardness Tester. Analysis of enamel surface destruction and enamel surface microscopic hardness shifting after a 60 sec application of H2PO4 (50% concentration) resulted in a decrease in acid solubility of enamel treated with anchovy substrate. This result can be seen with both the chewing and smearing method. S. insularis can be used as an alternative material for fluoridation.

Estimation of solubility of organo-phosphorus extractants by P determination using molybdovanadophosphoric acid method

International Nuclear Information System (INIS)

Gill, J.S.; Kotekar, M.K.; Singh, H.

2005-01-01

Solvent extraction processes have been found to be suitable for uranium recovery from phosphoric acid. Various extractants like di-2-ethyl hexylphosphoric acid (D2EHPA), di-nonylphenyl phosphoric acid (DNPPA) and synergistic agents like tri-butyl phosphate (TBP), tri-octyl phosphine oxide (TOPO) have been used in liquid-liquid extraction of uranium from phosphoric acid. Contents of these organo-phosphorus compounds in aqueous raffinates need estimation for process requirements. Solubility of Tri-butyl phosphate (TBP) and Di-2-ethylhexyl phosphoric acid (D2EHPA) extractants have been determined in different media of water, oxalic acid (0.6M) and sulphuric acid (3.75M) solutions. These compounds were estimated by determining their phosphorus (P) contents employing molybdovanadophosphoric acid method, after digesting and solubalizing them in nitric and perchloric acid. (author)

Hansen solubility parameters (HSP) for prescreening formulation of solid lipid nanoparticles (SLN): in vitro testing of curcumin-loaded SLN in MCF-7 and BT-474 cell lines.

Science.gov (United States)

Doktorovova, Slavomira; Souto, Eliana B; Silva, Amélia M

2018-01-01

Curcumin, a phenolic compound from turmeric rhizome (Curcuma longa), has many interesting pharmacological effects, but shows very low aqueous solubility. Consequently, several drug delivery systems based on polymeric and lipid raw materials have been proposed to increase its bioavailability. Solid lipid nanoparticles (SLN), consisting of solid lipid matrix and a surfactant layer can load poorly water-soluble drugs, such as curcumin, deliver them at defined rates and enhance their intracellular uptake. In the present work, we demonstrate that, despite the drug's affinity to lipids frequently used in SLN production, the curcumin amount loaded in most SLN formulations may be too low to exhibit anticancer properties. The predictive curcumin solubility in solid lipids has been thoroughly analyzed by Hansen solubility parameters, in parallel with the lipid-screening solubility tests for a range of selected lipids. We identified the most suitable lipid materials for curcumin-loaded SLN, producing physicochemically stable particles with high encapsulation efficiency (>90%). Loading capacity of curcumin in SLN allowed preventing the cellular damage caused by cationic SLN on MCF-7 and BT-474 cells but was not sufficient to exhibit drug's anticancer properties. But curcumin-loaded SLN exhibited antioxidant properties, substantiating the conclusions that curcumin's effect in cancer cells is highly dose dependent.

Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

Science.gov (United States)

Coal mine water (CMW) is typically treated to remove suspended solids, acidity, and soluble metals, but high concentrations of total dissolved solids (TDS) have been reported to impact the environment at several CMW discharge points. Consequently, various states have establishe...

Enhancement of solubility and oral bioavailability of manidipine by formation of ternary solid dispersion with d-α-tocopherol polyethylene glycol 1000 succinate and copovidone.

Science.gov (United States)

Chamsai, Benchawan; Limmatvapirat, Sontaya; Sungthongjeen, Srisagul; Sriamornsak, Pornsak

2017-12-01

Low bioavailability of oral manidipine (MDP) is due to its low water solubility. The objective of this study was to increase the solubility and bioavailability of MDP by fabricating ternary solid dispersion (tSD) with d-α-tocopherol polyethyleneglycol-1000-succinate and copovidone. In this study, solid ternary phase diagram was applied in order to check the homogeneity of tSD prepared by melting and solidifying with dry ice. The physicochemical properties of different formulations were determined by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and hot stage microscopy. Their solubility, dissolution, stability and bioavailability were also investigated. The results demonstrated that tSD obtained from ternary phase diagram divided into homogeneous and non-homogeneous regions. In the homogenous region, the transparent characteristics of tSD was observed and considered as a glass solution, which have a higher MDP solubility than that in non-homogenous region. The hot stage microscopy, DSC and PXRD confirmed that solid dispersion was formed in which MDP was molecularly dispersed in the carriers, especially in the homogenous region of phase diagram. FTIR analysis demonstrated strong hydrogen bonding between amine groups of MDP and carbonyl groups of copovidone, which supported a higher solubility and dissolution of tSD. The pharmacokinetic study in Wistar rats showed that the tSD had the greatest effect on oral bioavailability. Immediate hypotensive effect of tSD was also observed in vivo. The improvement of stability, dissolution and oral bioavailability of MDP could be achieved by using tSD technique.

Stability constants and solubility of neptunium and plutonium complexes with alkylphosphoric acids in TBP

International Nuclear Information System (INIS)

Fedoseev, D.A.; Romanovskaya, I.A.; Artemova, L.A.; Gibina, M.Yu.

1989-01-01

The concentration stability constants (K s ) and solubility of neptunium and plutonium complexes with di- and monobutylphosphoric acids (APA), as well as with orthophosphoric acid in the system composed of 30% TBP + n-dodecane, have been determined by spectrophotometric titration and radiometry. The feasibility of predicting the radiative chemical behavior of actinides based on their K s values and the radiative chemical yield of APA has been demonstrated

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

Energy Technology Data Exchange (ETDEWEB)

Mishelevich, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail: apelblat@bgu.ac.il

2008-05-15

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution.

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

International Nuclear Information System (INIS)

Mishelevich, Alexander; Apelblat, Alexander

2008-01-01

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution

Hydrogen solubility measurements of analyzed tall oil fractions and a solubility model

International Nuclear Information System (INIS)

Uusi-Kyyny, Petri; Pakkanen, Minna; Linnekoski, Juha; Alopaeus, Ville

2017-01-01

Highlights: • Hydrogen solubility was measured in four tall oil fractions between 373 and 597 K. • Continuous flow synthetic isothermal and isobaric method was used. • A Henry’s law model was developed for the distilled tall oil fractions. • The complex composition of the samples was analyzed and is presented. - Abstract: Knowledge of hydrogen solubility in tall oil fractions is important for designing hydrotreatment processes of these complex nonedible biobased materials. Unfortunately measurements of hydrogen solubility into these fractions are missing in the literature. This work reports hydrogen solubility measured in four tall oil fractions between 373 and 597 K and at pressures from 5 to 10 MPa. Three of the fractions were distilled tall oil fractions their resin acids contents are respectively 2, 20 and 23 in mass-%. Additionally one fraction was a crude tall oil (CTO) sample containing sterols as the main neutral fraction. Measurements were performed using a continuous flow synthetic isothermal and isobaric method based on the visual observation of the bubble point. Composition of the flow was changed step-wise for the bubble point composition determination. We assume that the tall oil fractions did not react during measurements, based on the composition analysis performed before and after the measurements. Additionally the densities of the fractions were measured at atmospheric pressure from 293.15 to 323.15 K. A Henry’s law model was developed for the distilled tall oil fractions describing the solubility with an absolute average deviation of 2.1%. Inputs of the solubility model are temperature, total pressure and the density of the oil at 323.15 K. The solubility of hydrogen in the CTO sample can be described with the developed model with an absolute average deviation of 3.4%. The solubility of hydrogen increases both with increasing pressure and/or increasing temperature. The more dense fractions of the tall oil exhibit lower hydrogen

Complete doping in solid-state by silica-supported perchloric acid as dopant solid acid: Synthesis and characterization of the novel chiral composite of poly [(±)-2-(sec-butyl) aniline

Energy Technology Data Exchange (ETDEWEB)

Farrokhzadeh, Abdolkarim; Modarresi-Alam, Ali Reza, E-mail: modaresi@chem.usb.ac.ir

2016-05-15

Poly [(±)-2-(sec-butyl) aniline]/silica-supported perchloric acid composites were synthesized by combination of poly[(±)-2-sec-butylaniline] base (PSBA) and the silica-supported perchloric acid (SSPA) as dopant solid acid in solid-state. The X-ray photoelectron spectroscopy (XPS) and CHNS results confirm nigraniline oxidation state and complete doping for composites (about 75%) and non-complete for the PSBA·HCl salt (about 49%). The conductivity of samples was (≈0.07 S/cm) in agreement with the percent of doping obtained of the XPS analysis. Also, contact resistance was determined by circular-TLM measurement. The morphology of samples by the scanning electron microscopy (SEM) and their coating were investigated by XPS, SEM-map and energy-dispersive X-ray spectroscopy (EDX). The key benefits of this work are the preparation of conductive chiral composite with the delocalized polaron structure under green chemistry and solid-state condition, the improvement of the processability by inclusion of the 2-sec-butyl group and the use of dopant solid acid (SSPA) as dopant. - Highlights: • The solid-state synthesis of the novel chiral composites of poly[(±)-2-(sec-butyl)aniline] (PSBA) and silica-supported perchloric acid (SSPA). • It takes 120 h for complete deprotonation of PSBA.HCl salt. • Use of SSPA as dopant solid acid for the first time to attain the complete doping of PSBA. • The coating of silica surface with PSBA.

Solubility behavior and biopharmaceutical classification of novel high-solubility ciprofloxacin and norfloxacin pharmaceutical derivatives.

Science.gov (United States)

Breda, Susana A; Jimenez-Kairuz, Alvaro F; Manzo, Ruben H; Olivera, María E

2009-04-17

The hydrochlorides of the 1:3 aluminum:norfloxacin and aluminum:ciprofloxacin complexes were characterized according to the Biopharmaceutics Classification System (BCS) premises in comparison with their parent compounds. The pH-solubility profiles of the complexes were experimentally determined at 25 and 37 degrees C in the range of pH 1-8 and compared to that of uncomplexed norfloxacin and ciprofloxacin. Both complexes are clearly more soluble than the antibiotics themselves, even at the lowest solubility pHs. The increase in solubility was ascribed to the species controlling solubility, which were analyzed in the solid phases at equilibrium at selected pHs. Additionally, permeability was set as low, based on data reported in the scientific literature regarding oral bioavailability, intestinal and cell cultures permeabilities and also considering the influence of stoichiometric amounts of aluminum. The complexes fulfill the BCS criterion to be classified as class 3 compounds (high solubility/low permeability). Instead, the active pharmaceutical ingredients (APIs) currently used in solid dosage forms, norfloxacin and ciprofloxacin hydrochloride, proved to be BCS class 4 (low solubility/low permeability). The solubility improvement turns the complexes as potential biowaiver candidates from the scientific point of view and may be a good way for developing more dose-efficient formulations. An immediate release tablet showing very rapid dissolution was obtained. Its dissolution profile was compared to that of the commercial ciprofloxacin hydrochloride tablets allowing to dissolution of the complete dose at a critical pH such as 6.8.

Incorporation of Mg and Ca into nanostructured Fe2O3 improves Fe solubility in dilute acid and sensory characteristics in foods.

Science.gov (United States)

Hilty, Florentine M; Knijnenburg, Jesper T N; Teleki, Alexandra; Krumeich, Frank; Hurrell, Richard F; Pratsinis, Sotiris E; Zimmermann, Michael B

2011-01-01

Iron deficiency is one of the most common micronutrient deficiencies worldwide. Food fortification can be an effective and sustainable strategy to reduce Fe deficiency but selection of iron fortificants remains a challenge. Water-soluble compounds, for example, FeSO(4), usually demonstrate high bioavailability but they often cause unacceptable sensory changes in foods. On the other hand, poorly acid-soluble Fe compounds, for example FePO(4), may cause fewer adverse sensory changes in foods but are usually not well bioavailable since they need to be dissolved in the stomach prior to absorption. The solubility and the bioavailability of poorly acid-soluble Fe compounds can be improved by decreasing their primary particle size and thereby increasing their specific surface area. Here, Fe oxide-based nanostructured compounds with added Mg or Ca were produced by scalable flame aerosol technology. The compounds were characterized by nitrogen adsorption, X-ray diffraction, transmission electron microscopy, and Fe solubility in dilute acid. Sensory properties of the Fe-based compounds were tested in 2 highly reactive, polyphenol-rich food matrices: chocolate milk and fruit yoghurt. The Fe solubility of nanostructured Fe(2)O(3) doped with Mg or Ca was higher than that of pure Fe(2)O(3). Since good solubility in dilute acid was obtained despite the inhomogeneity of the powders, inexpensive precursors, for example Fe- and Ca-nitrates, can be used for their manufacture. Adding Mg or Ca lightened powder color, while sensory changes when added to foods were less pronounced than for FeSO(4). The combination of high Fe solubility and low reactivity in foods makes these flame-made nanostructured compounds promising for food fortification. Practical Application: The nanostructured iron-containing compounds presented here may prove useful for iron fortification of certain foods; they are highly soluble in dilute acid and likely to be well absorbed in the gut but cause less severe

Solubility of Carbon in Nanocrystalline -Iron

OpenAIRE

Alexander Kirchner; Bernd Kieback

2012-01-01

A thermodynamic model for nanocrystalline interstitial alloys is presented. The equilibrium solid solubility of carbon in -iron is calculated for given grain size. Inside the strained nanograins local variation of the carbon content is predicted. Due to the nonlinear relation between strain and solubility, the averaged solubility in the grain interior increases with decreasing grain size. The majority of the global solubility enhancement is due to grain boundary enrichment however. Therefor...

Thermodynamic approach to improving solubility prediction of co-crystals in comparison with individual poorly soluble components

International Nuclear Information System (INIS)

Perlovich, German L.

2014-01-01

Highlights: • Thermodynamic approach for solubility improvement of co-crystal was developed. • The graphical technique for estimation of co-crystal solubility was elaborated. • Hydration enthalpies of some drugs and amino acids were calculated. • Applicability/operability of the approach was exemplified by some drugs and amino acids. - Abstract: A novel thermodynamic approach to compare poorly soluble components (active pharmaceutical ingredient (API)) both in co-crystals and individual compounds was developed. An algorithm of choosing potential co-crystals with improved solubility characteristics on the basis of the known solvation/hydration API and co-former enthalpies is described. The applicability and operability of the algorithm were tested exemplified by some drugs and amino acids

Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

Science.gov (United States)

Piper, D.Z.; Wandless, G.A.

1992-01-01

The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

Environmentally Benign Bifunctional Solid Acid and Base Catalysts

NARCIS (Netherlands)

Elmekawy, A.; Shiju, N.R.; Rothenberg, G.; Brown, D.R.

2014-01-01

Solid bifunctional acid-​base catalysts were prepd. in two ways on an amorphous silica support: (1) by grafting mercaptopropyl units (followed by oxidn. to propylsulfonic acid) and aminopropyl groups to the silica surface (NH2-​SiO2-​SO3H)​, and (2) by grafting only aminopropyl groups and then

Thermodynamic Modeling of Several Aqueous Alkanol Solutions Containing Amino Acids with the Perturbed-Chain Statistical Associated Fluid Theory Equation of State

DEFF Research Database (Denmark)

Ferreira, Luisa; Breil, Martin Peter; Pinho, S. P.

2009-01-01

parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid...... and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino acids...... in water, but the correlation for the solubility in pure alcohols was not so satisfactory. The solubility in mixed solvents (ternary systems) was predicted on the basis of the modeling of the solubility in pure solvents, without any additional fitting of the parameters, and the results achieved were...

Pure Phase Solubility Limits: LANL

International Nuclear Information System (INIS)

C. Stockman

2001-01-01

The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO 2 partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility products

Pure Phase Solubility Limits: LANL

Energy Technology Data Exchange (ETDEWEB)

C. Stockman

2001-01-26

The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility

Synthesis, structural, solubility and anticancer activity studies of salts using nucleobases and sulfonic acids coformer

Science.gov (United States)

Singh, Neetu; Singh, Udai P.; Nikhil, Kumar; Roy, Partha; Singh, Hariji

2017-10-01

The reactions of natural and unnatural nucleobases (cytosine (Cyt), adenine (Ade), 5-aminouracil (AU) and caffeine (Caff)) with sulfonic acids coformer (1,5-naphthalenedisulfonic acid, NDSA; 5-sulfosalicylic acid, SSA) resulted in the formation of salts viz. [NDSA.Cyt] (1), [NDSA.Ade] (2), [NDSA.AU] (3), [NDSA.Caff] (4), [SSA.Cyt] (5), [SSA.Ade] (6), [SSA.AU] (7), and [SSA.Caff] (8). The structural analysis revealed that salts 1, 4, 6 and 7 have intermolecular interactions between adjacent nucleobases which form two different homodimer shown in R22 (8) motif and assembled via complementary Nsbnd H⋯O and Nsbnd H⋯N interactions. However, in all other salts an intermediate supramolecular synthon pattern was observed between nucleobases and sulfonic acids. The lattice energy was also calculated by DFT to investigate whether salts were thermodynamically more stable than its coformer. The same was further confirmed by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis. The anticancer activity study of individual nucleobases and their NDSA salts were also performed on human breast (MCF-7) and lung (A 549) cancer cell. The salts formation of nucleobases with sulfonic acids improved their solubility, thereby demonstrating up to 8-fold increase in solubility of nucleobases.

Diagnosing solubility limitations – the example of hydrate formation

Directory of Open Access Journals (Sweden)

Joerg Berghausen

2014-07-01

Full Text Available Solubility is regarded as one of the key challenges in many drug discovery projects. Thus, it’s essential to support the lead finding and optimization efforts by appropriate solubility data. In silico solubility prediction remains challenging and therefore a screening assay is used as a first filter, followed by selected follow-up assays to reveal what causes the low solubility of a specific compound or chemotype. Results from diagnosing the underlying reason for solubility limitation are discussed. As lipophilicity and crystal lattice forces are regarded as main contributors to limiting solubility, changes in solid state are important to be recognized. Solubility limitation by various factors will be presented and the impact of the solid-state is exemplified by compounds that are able to form hydrates.

Potable NIR spectroscopy predicting soluble solids content of pears based on LEDs

Energy Technology Data Exchange (ETDEWEB)

Liu Yande; Liu Wei; Sun Xudong; Gao Rongjie; Pan Yuanyuan; Ouyang Aiguo, E-mail: jxliuyd@163.com [School of Mechatronics Engineering, East China Jiaotong University, Changbei Open and Developing District, Nanchang, 330013 (China)

2011-01-01

A portable near-infrared (NIR) instrument was developed for predicting soluble solids content (SSC) of pears equipped with light emitting diodes (LEDs). NIR spectra were collected on the calibration and prediction sets (145:45). Relationships between spectra and SSC were developed by multivariate linear regression (MLR), partial least squares (PLS) and artificial neural networks (ANNs) in the calibration set. The 45 unknown pears were applied to evaluate the performance of them in terms of root mean square errors of prediction (RMSEP) and correlation coefficients (r). The best result was obtained by PLS with RMSEP of 0.62{sup 0}Brix and r of 0.82. The results showed that the SSC of pears could be predicted by the portable NIR instrument.

Potable NIR spectroscopy predicting soluble solids content of pears based on LEDs

International Nuclear Information System (INIS)

Liu Yande; Liu Wei; Sun Xudong; Gao Rongjie; Pan Yuanyuan; Ouyang Aiguo

2011-01-01

A portable near-infrared (NIR) instrument was developed for predicting soluble solids content (SSC) of pears equipped with light emitting diodes (LEDs). NIR spectra were collected on the calibration and prediction sets (145:45). Relationships between spectra and SSC were developed by multivariate linear regression (MLR), partial least squares (PLS) and artificial neural networks (ANNs) in the calibration set. The 45 unknown pears were applied to evaluate the performance of them in terms of root mean square errors of prediction (RMSEP) and correlation coefficients (r). The best result was obtained by PLS with RMSEP of 0.62 0 Brix and r of 0.82. The results showed that the SSC of pears could be predicted by the portable NIR instrument.

Drug-drug cocrystals of antituberculous 4-aminosalicylic acid: Screening, crystal structures, thermochemical and solubility studies.

Science.gov (United States)

Drozd, Ksenia V; Manin, Alex N; Churakov, Andrei V; Perlovich, German L

2017-03-01

Experimental multistage cocrystal screening of the antituberculous drug 4-aminosalicylic acid (PASA) has been conducted with a number of coformers (pyrazinamide (PYR), nicotinamide (NAM), isonicotinamide (iNAM), isoniazid (INH), caffeine (CAF) and theophylline (TPH)). The crystal structures of 4-aminosalicylic acid cocrystals with isonicotinamide ([PASA+iNAM] (2:1)) and methanol solvate with caffeine ([PASA+CAF+MeOH] (1:1:1)) have been determined by single X-ray diffraction experiments. For the first time for PASA cocrystals it has been found that the structural unit of the [PASA+iNAM] cocrystal (2:1) is formed by 2 types of heterosynthons: acid-pyridine and acid-amide. The desolvation study of the [PASA+CAF+MeOH] cocrystal solvate (1:1:1) has been conducted. The correlation models linking the melting points of the cocrystals with the melting points of the coformers used in this paper have been developed. The thermochemical and solubility properties for all the obtained cocrystals have been studied. Cocrystallization has been shown to lead not only to PASA solubility improving but also to its higher stability against the chemical decomposition. Copyright © 2016 Elsevier B.V. All rights reserved.

Soluble CD30 serum level--an adequate marker for allograft rejection of solid organs?

Science.gov (United States)

Schlaf, G; Altermann, W W; Rothhoff, A; Seliger, B

2007-11-01

The CD30 molecule, a 120 kDa cell surface glycoprotein, is a member of the tumor necrosis factor receptor (TNF-R) superfamily and was originally identified on the surface of Reed-Sternberg cells and anaplastic large cell lymphomas in Hodgkin's disease patients. In addition to lymphoproliferative disorders the expression of CD30 was found in both activated CD8+ and CD4+ Th2 cells which lead to the activation of B-cells and consequently to the inhibition of the Th1-type cellular immunity. The membrane-bound CD30 molecule can be proteolytically cleaved, thereby generating a soluble form (sCD30) of about 85 kDa. Low serum levels of soluble CD30 were found in healthy humans, whereas increased sCD30 serum concentrations were detected under pathophysiological situations such as systemic lupus erythematosus, rheumatoid arthritis, certain viral infections and adult T cell leukaemia/lymphoma. In addition, it has recently been suggested that pre- or post-transplant levels of sCD30 represent a biomarker for graft rejection associated with an impaired outcome for transplanted patients. We here review (i) the current knowledge of the clinical significance of sCD30 serum levels for solid organ transplantations and (ii) our own novel data regarding inter- and intra-individual variations as well as time-dependent alterations of sCD30 levels in patients. (iii) Based on this information the implementation of sCD30 as predictive pre-transplant or post-transplant parameter for solid organ transplantation is critically discussed.

Thermodynamic model of Ni(II) solubility, hydrolysis and complex formation with ISA

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Siso, Maria Rosa; Duro, Lara; Bruno, Jordi [Amphos21, Barcelona (Spain); Gaona, Xavier; Altmaier, Marcus [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Nuclear Waste Disposal

2018-04-01

The solubility of β-Ni(OH){sub 2}(cr) was investigated at T=(22±2) C in the absence and presence of α-isosaccharinic acid (ISA), the main degradation product of cellulose under alkaline pH conditions. Batch solubility experiments were performed from undersaturation conditions under inert gas (Ar) atmosphere. Solubility experiments in the absence of ISA were conducted in 0.5 and 3.0 M NaCl-NaOH solutions at 7.5 ≤ pH{sub m} ≤ 13 (with pH{sub m} = -log{sub 10}[H{sup +}]). XRD analyses of selected solid phases collected after completing the solubility experiments (∼300 days) confirmed that β-Ni(OH){sub 2}(cr) remains as solid phase controlling the solubility of Ni(II) in all investigated conditions. Based on the slope analysis (log{sub 10}[Ni] vs. pH{sub m}) of the solubility data and solid phase characterization, the equilibrium reactions β-Ni(OH){sub 2}(cr)+2 H{sup +} <=> Ni{sup 2+}+2 H{sub 2}O(l) and β-Ni(OH){sub 2}(cr) <=> Ni(OH){sub 2}(aq) were identified as controlling the solubility of Ni(II) within the investigated pH{sub m} region. The conditional equilibrium constants determined from the solubility experiments at different ionic strengths were evaluated with the specific ion interaction theory (SIT). In contrast to the current thermodynamic selection in the NEA-TDB, solubility data collected in the present work does not support the formation of the anionic hydrolysis species Ni(OH){sub 3}{sup -} up to pH{sub m} ≤ 13.0. Solubility experiments in the presence of ISA were conducted in 0.5 M NaCl-NaOH-NaISA solutions with 0.01 M ≤ [NaISA] ≤ 0.2 M and 9 ≤ pH{sub m} ≤ 13. XRD analyses confirmed that β-Ni(OH){sub 2}(cr) is also the solid phase controlling the solubility of Ni(II) in the presence of ISA. Solubility data of all investigated systems can be properly explained with chemical and thermodynamic models including the formation of the complexes NiOHISA(aq), Ni(OH){sub 2}ISA{sup -} and Ni(OH){sub 3}ISA{sup 2-}. The reported data confirm

The participation of soluble factors in the omega-oxidation of fatty acids in the liver of the sheep

International Nuclear Information System (INIS)

Hare, W.R.; Wahle, K.W.

1991-01-01

The removal of soluble components from an ovine hepatic microsomal preparation decreased the omega-hydroxylation of dodecanoic and hexadecanoic acids. The results suggest that one or more soluble components play a role in the microsomal omega-hydroxylation of fatty acids. The possible roles in the reaction of catalase (known to stimulate the microsomal desaturations of fatty acids and alkylglycerols) and superoxide dismutase were investigated. The addition of these enzymes to the complete (but not the washed) microsomal preparation stimulated both the initial omega-hydroxylation reaction and the subsequent dehydrogenation reactions of the omega-oxidation pathway. The similarity of the effects of catalase and superoxide dismutase and stimulation of two different steps of the omega-oxidation pathway suggest that these agents are acting indirectly by removing active oxygen species rather than directly on the enzymes of microsomal fatty acid omega-hydroxylation

Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate.

Science.gov (United States)

Yousaf, Abid Mehmood; Mustapha, Omer; Kim, Dong Wuk; Kim, Dong Shik; Kim, Kyeong Soo; Jin, Sung Giu; Yong, Chul Soon; Youn, Yu Seok; Oh, Yu-Kyoung; Kim, Jong Oh; Choi, Han-Gon

2016-01-01

The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate. Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP) and Labrafil(®) M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion. All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1:4:0.5 resulted in a particle size of water-soluble fenofibrate.

An experimental and theoretical investigation of loperamide hydrochloride-glutaric acid cocrystals.

Science.gov (United States)

Bruni, Giovanna; Maietta, Mariarosa; Maggi, Lauretta; Mustarelli, Piercarlo; Ferrara, Chiara; Berbenni, Vittorio; Freccero, Mauro; Scotti, Federico; Milanese, Chiara; Girella, Alessandro; Marini, Amedeo

2013-07-11

Cocrystallization is a powerful method to improve the physicochemical properties of drugs. Loperamide hydrochloride is a topical analgesic for the gastrointestinal tract showing low and pH-dependent solubility; for this reason, an enhancement of its solubility or dissolution rate, particularly at the pH of the intestinal tract, could improve its local efficacy. Here we prepared cocrystals of this active principle with glutaric acid and so obtained a new crystalline solid representing a viable alternative to improve the physicochemical properties and thus the pharmaceutical behavior of the drug. Differential scanning calorimetry, X-ray powder diffraction, Fourier infrared spectroscopy, solid-state NMR, and scanning electron microscopy coupled to the energy-dispersive X-ray spectrometry were used to investigate the new solid-phase formation. DFT calculations at B3LYP/6-31G(d) level of theory, in the gas phase, including frequencies computation, provided a rationale for the interaction between loperamide hydrochloride and glutaric acid. The cocrystals showed improved water solubility in comparison with loperamide HCl, and the pharmaceutical formulation proposed was able to release the drug more rapidly in comparison with three reference commercial products when tested at neutral pH values.

Synthesis and Anchoring of Antineoplastic Ferrocene and Phthalocyanine Derivatives on Water-Soluble Polymeric Drug Carriers Derived from Lysine and Aspartic Acid

OpenAIRE

Maree, M. David; Neuse, Eberhard W.; Erasmus, Elizabeth; Swarts, Jannie C.

2007-01-01

The general synthetic strategy towards water-soluble biodegradable drug carriers and the properties that they must have are discussed. The syntheses of water-soluble biodegradable copolymers of lysine and aspartic acid as potential drug-delivering devices, having amine-functionalised side chains are then described. Covalent anchoring of carboxylic acid derivatives of the antineoplastic ferrocene and photodynamically active phthalocyanine moieties to the amine-containing drug carrier copolymer...

Preparation of hydrolytic liquid from dried distiller's grains with solubles and fumaric acid fermentation by Rhizopus arrhizus RH 7-13.

Science.gov (United States)

Liu, Huan; Yue, Xuemin; Jin, Yuhan; Wang, Meng; Deng, Li; Wang, Fang; Tan, Tianwei

2017-10-01

Fumaric acid production from lignocellulosic materials is an alternative chemicals production system. This work investigated the suitable conditions for hydrolysis of dried distiller's grains with solubles (DDGS). The hydrolytic liquid was subsequently used for the production of fumaric acid. After optimizing the hydrolysis conditions, the most suitable concentration of H 2 SO 4 (2%), hydrolysis temperature (120 °C), hydrolysis time (100min) and solid/liquid ratio (1:10) were obtained. The yield of monosaccharides reached 258 mg/g DDGS and 15.88 g/L glucose, 7.53 g/L xylose and 2.35 g/L arabinose were obtained in unprocessed hydrolytic liquid. The furfural inhibitor in the hydrolytic liquid was also detected and the yield of it was reducing progressively in the pretreatment process. The ferment ability of the hydrolytic liquid from DDGS was tested through the process of fumaric acid production by Rhizopus arrhizus RH 7-13. The unprocessed hydrolytic liquid was not appropriate for the fermentation process. The yield of fumaric acid from the concentrated processed hydrolytic liquid reached 18.93 g/L, which was close to the yield of fermenting 80 g/L glucose. This result indicated that the commonly used carbon resource glucose could to some extent be replaced by processed hydrolytic liquid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of solubility isotherms of barium and strontium nitrates in the system acetic acid-water at 250 C

International Nuclear Information System (INIS)

Hubicki, W.; Piskorek, M.

1976-01-01

Investigastions of the solubility of barium and strontium nitrates were carried out in the system: acetic acid - water at 25 0 C. When one compares the isotherms of solubility of barium and strontium nitrates, one can observe that it is possible to separate the admixtures of barium from strontium nitrates as a result of fractional crystallization of these nitrates from actic acid solution at the temperatures lower than 31.3 0 C, i.e. below the temperature of transformation: Sr(NO 3 ) 2 . 4H 2 O reversible to Sr(NO 3 ) 2 + 4H 2 O for aqueous solution. (author)

Characterization of Acid Soluble Collagen from Redbelly Yellowtail Fusilier Fish Skin (Caesio cuning

Directory of Open Access Journals (Sweden)

Ika Astiana

2016-04-01

Full Text Available Fish skin can be used as raw material for producing collagen. The collagen can be extracted by chemicalor combination of chemical and enzymatic processes. Extraction of collagen chemically can do with theacid process that produces acid soluble collagen (ASC. This study aimed to determine the optimumconcentration and time of pretreatment and extraction, also to determine the characteristics of the acidsoluble collagen from the skin of yellow tail fish. Extraction of collagen done by pretreatment using NaOH atthe concentration of 0.05; 0.1; and 0.15 M and extraction using acetic acid at the concentration of 0.3; 0.5; and0.7 M. Pretreatment NaOH with concentration 0.05 M and soaking time of 8 hours is the best combinationfor eliminating non collagen protein. Combination treatment of acetic acid at the concentration of 0.3 Mfor 3 days obtained the best solubility. The yield of collagen ASC was 18.4±1.49% (db and 5.79±0.47%(wb. Amino acid composition that is dominant in the ASC collagen was glycine (25.09±0.003%, alanine(13.71±0.075%, and proline (12.15±0.132%. Collagen from yellow tail fish skin has α1, α2, β and γprotein structure with the molecular weight of 125, 113, 170-181, and 208 KDa. The transition and meltingtemperatures of collagen were 67.69oC and 144.4oC. The surface structure of collagen by analysis of SEM hasfibers on the surface.Keywords: cholesterol, fatty acids, meat tissue, proximate, red snapper (L. argentimaculatus

Kinetics of the isothermal decomposition of zirconium hydride: terminal solid solubility for precipitation and dissolution

Science.gov (United States)

Denisov, E. A.; Kompaniets, T. N.; Voyt, A. P.

2018-05-01

The hydrogen permeation technique in the surface-limited regime (SLR) was first used to study the isothermal decomposition of zirconium hydride. It is shown that under isothermal conditions, the hydrogen terminal solid solubility in the α-phase for hydride precipitation (TSSp) and dissolution (TSSd) differ only by 6%, in contrast to the 20-30% indicated in the available literature. It is demonstrated that even the minimum heating/cooling rate (1 C/min) used in the traditional methods of studying TSSp and TSSd is too high to exclude the effect of kinetics on the results obtained.

Using cocrystals to systematically modulate aqueous solubility and melting behavior of an anticancer drug.

Science.gov (United States)

Aakeröy, Christer B; Forbes, Safiyyah; Desper, John

2009-12-02

Five cocrystals of an anticancer compound have been assembled using a well-defined hydrogen-bond-based supramolecular approach that produced the necessary structural consistency in the resulting solids. These cocrystals contain aliphatic even-numbered dicarboxylic acids of increasing chain length, and as a result, the physical properties of the cocrystals can be related to the molecular structure of the acid. The melting points of the five cocrystals show an excellent correlation with the melting points of the individual acids, and it has also been shown that aqueous solubility can be increased by a factor of 2.5 relative to that of the individual drug. Consequently, cocrystals can offer a range of solid forms from which can be chosen an active ingredient where a particular physical property can be dialed in, provided that the cocrystals show considerable structural consistency and that systematic changes are made to the participating cocrystallizing agents.

Mechanical properties, phenolic composition and extractability indices of Barbera grapes of different soluble solids contents from several growing areas.

Science.gov (United States)

Torchio, Fabrizio; Cagnasso, Enzo; Gerbi, Vincenzo; Rolle, Luca

2010-02-15

Phenolic compounds, extractable from grape skins and seeds, have a notable influence on the quality of red wines. Many studies have clearly demonstrated the relationship between the phenolic composition of the grape at harvest time and its influence on the phenolic composition of the red wine produced. In many previous works the evolution of phenolic composition and relative extractability was normally studied on grapes sampled at different times during ripening, but at the same date the physiological characteristics of grape berries in a vineyard are often very heterogeneous. Therefore, the main goal of the study is to investigate the differences among mechanical properties, phenolic composition and relative extractability of Vitis vinifera L. cv Barbera grape berries, harvested at the same date from several vineyards, and calibrated according to their density at three levels of soluble solids (A=235+/-8, B=252+/-8 and C=269+/-8 g L(-1) sugar) with the aim of studying the influence of ripeness stages and growing locations on these parameters. Results on mechanical properties showed that the thickness of the berry skin (Sp(sk)) was the parameter most affected by the different level of sugars in the pulp, while different skin hardnesses, evaluated by the break skin force (F(sk)), were related to the cultivation sites. The latter were also observed to influence the mechanical characteristics of seeds. Generally, the anthocyanin content increased with the level of soluble solids, while the increase in the tannin content of the berry skin and seeds was less marked. However, significant changes in flavanols reactive to vanillin in the seeds were found. The cellular maturity index (EA%) was little influenced by the soluble solids content of grapes. Copyright 2009 Elsevier B.V. All rights reserved.

Solid phase syntheses of oligoureas

Energy Technology Data Exchange (ETDEWEB)

Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)

1997-02-19

Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.

Development of an irrigation control device based on solar radiation and its adaptability for cultivation of high soluble solid tomato fruit in root zone restriction culture

International Nuclear Information System (INIS)

Nitta, M.; Shibuya, K.; Kubai, K.; Komatsu, H.; Hosokawa, T.; Nakamura, K.

2009-01-01

An irrigation control device based on solar radiation was developed to allow automatic irrigation management for high soluble solid tomato fruit production in root zone restriction culture. Its adaptability for long-term cultivation (planting carried out in early September and harvesting ending in late June) of high soluble solid tomato fruit in root zone restriction culture was examined. The following results were obtained: 1. The control device was composed of generally available electronic parts. A change of setting was possible for the irrigation starting point, the irrigation time period, and the once amount of irrigation. For the first irrigation of the day, one of two irrigation control modes can be chosen; the first determines irrigation dependent on the solar radiation after the irrigated time of the previous day. The second mode irrigates at a set time. 2. The correlation between the total integrated solar radiation and the evapotranspiration rate of tomato plants were investigated. Positive correlations were observed for each month from October to June. Moreover, total integrated solar radiation per unit evapotranspiration was different for each month. 3. In long-term cultivation of tomato fruit using this device, the marketable yield of high soluble solid tomato fruit (more than Brix 8%) was 9.7t/10a. 4. This device exhibited the necessary adaptability for use in long-term cultivation of high soluble solid tomato fruit in root zone restriction culture, by changing the set value of the irrigation starting point and the irrigation time period in accordance with the growth period

SOLID AND LIQUID PINEAPPLE WASTE UTILIZATION FOR LACTIC ACID FERMENTATION USING Lactobacillus delbrueckii

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Abdullah Abdullah

2012-01-01

Full Text Available The liquid and solid  pineapple wastes contain mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for fermentation to produce organic acid. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were  carried out in batch fermentation using  the  liquid and solid pineapple wastes to produce lactic acid. The anaerobic fermentation of lactic acid were performed at 40 oC, pH 6, 5% inocolum and  50 rpm. Initially  results show that the liquid pineapple waste by  using Lactobacillus delbrueckii can be used as carbon source  for lactic acid fermentation. The production of lactic acid  are found to be 79 % yield, while only  56% yield was produced by using solid waste. 

The solubilities and solubility products of zirconium hydroxide and oxide after aging at 278, 313, and 333 K

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Taishi; Uemura, Takuya; Sasaki, Takayuki; Takagi, Ikuji [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Moriyama, Hirotake [Kyoto Univ. (Japan). Research Reactor Inst.

2016-07-01

The solubilities of zirconium hydroxide and oxide after aging at 278, 313, and 333 K were measured at 278, 298, 313, and 333 K in the pH{sub c} range of 0.3-7 in a 0.5 M ionic strength solution of NaClO{sub 4} and HClO{sub 4}. Size distributions of the colloidal species were investigated by ultrafiltration using membranes with different pore sizes, and the solid phases were examined by X-ray diffraction. The apparent solubility of zirconium amorphous hydroxide (Zr(OH){sub 4}(am)), prepared by the oversaturation method, decreased with increasing aging temperature (T{sub a}), and the size distributions obtained after aging at elevated temperatures indicated the growth of the colloidal species. We, therefore, suggested that agglomeration of the colloidal species and dehydration and crystallization of Zr(OH){sub 4}(am) as the solubility-limiting solid phase occurred over the course of aging at elevated temperatures. For sample solutions of the crystalline oxide (ZrO{sub 2}(cr)), the aging temperature had no significant effect on the solubility, but the solubility data at lower temperatures were found to be slightly higher than those at higher temperatures, implying a small fraction of the amorphous components. In the analysis of different solid phases (Zr(OH){sub 4}(s,T{sub a}), T{sub a} = 278, 313, and 333 K) depending on the aging temperatures, the solubility products (K{sub sp}, T{sub a}) were determined at different measurement temperatures, and the enthalpy change (Δ{sub r}H {sup circle}) for Zr{sup 4+} 4OH{sup -} <=> Zr(OH){sub 4}(s,T{sub a}) was calculated using the van't Hoff equation. The solid-phase-transformation process at elevated temperatures was also analyzed based on the obtained K{sub sp}, T{sub a} and Δ{sub r}H {sup circle} values.

All-solid-state potentiometric sensors for ascorbic acid by using a screen-printed compatible solid contact

International Nuclear Information System (INIS)

Veltsistas, Panayotis G.; Prodromidis, Mamas I.; Efstathiou, Constantinos

2004-01-01

The development of all-solid-state potentiometric ion selective electrodes for monitoring of ascorbic acid, by using a screen-printed compatible solid contact is described. The applied methodology is based on the use of PVC membrane modified with some firstly-tested ionophores (triphenyltin(IV)chloride, triphenyltin(IV)hydroxide and palmitoyl-L-ascorbic acid) and a novel one synthesized in our laboratory (dibutyltin(IV) diascorbate). Synthesis protocol and some preliminary identification studies are given. A conductive graphite-based polymer thick film ink was used as an internal solid contact between the graphite electrode and the PVC membrane. The presence and the nature of the solid contact (plain or doped with lanthanum 2,6-dichlorophenolindophenol (DCPI)) seem to enhance the analytical performance of the electrodes in terms of sensitivity, dynamic range, and response time. The analytical performance of the constructed electrodes was evaluated with potentiometry, constant-current chronopotentiometry and electrochemical impedance spectroscopy (EIS). The interference effect of various compounds was also tested. The potential response of the optimized Ph 3 SnCl-based electrode was linear against ascorbic acid concentration range 0.005-5.0 mM. The applicability of the proposed sensors in real samples was also tested. The detection limit was 0.002 mM ascorbic acid (50 mM phosphate, pH 5 in 50 mM KCl). The slope of the electrodes was super-Nernstian and pH dependent, indicating a mechanism involving a combination of charge transfer and ion exchange processes. Fabrication of screen-printed ascorbate ISEs has also been demonstrated

Terminal solid solubility of hydrogen in titanium

International Nuclear Information System (INIS)

Giroldi, J.P.; Vizcaino, Pablo; Banchik, Abraham David

2003-01-01

A Research and Development program to build a data base is currently under progress to support the local titanium fabrication. In the present work the temperature of the Terminal Solid Solubility on dissolution (TSSd) and precipitation (TSSp) of titanium hydrides in the Ti α-phase were both measured in the same thermal cycle with a Differential Scanning Calorimeter (DSC). The local titanium producer (FAESA) provided ASTM grade 1 pure Ti bars of about 2,5 cm in diameter. Samples weighting between 50 to 200 mg were cut with a diamond disc and the parallelepiped faces were all carefully ground with SiC papers, then picked in a HNO 3 plus HF aqueous solution and finally dried out with ethanol and hot air. Pairs of (TSSd, TSSp) values for α + δ → α and α → α + δ transformation temperatures in titanium were determined with the same calorimetric procedure already used to calculate the TSS values in zirconium. Data were taken from the same sample during the heating up and cooling down cycle of the second calorimeter run made with the same rate of 20 C degrees / minute. The Cathodic Charging technique was used to charge the samples at different hydrogen concentrations between the 'as fabricated' value and the concentration corresponding to the eutectoid temperature. A mixture of glycerin and phosphoric acid in a 2:1 ratio and a current density of 0,05 to 0,1 Amp/cm 2 were applied to different samples during 24 to 96 hours to get a wide range of hydrogen concentrations. A homogenization heat treatment at 400 C degrees for 45 minutes -made at open air in an electric furnace- was applied to each sample to dissolve the massive hydrides at the sample surfaces and diffuse them into the bulk of the sample. The hydrogen concentration of each sample was measured after the final calorimetric run using the Extraction Method in Liquid State under an inert atmosphere using a Leco RH-404 model Hydrogen Determinator. The experimental data follows a linear relationship -with a

Threshold value of enamel mineral solubility and dental erosion after consuming acidic soft drinks

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Muhammad Ilyas

2011-09-01

Full Text Available Background: Dental erosion is irreversible and can caused by acidic soft drink consumption. Dental erosion prevention had already been done, but it still has not been satisfying since the consumption of acidic soft drink is still high. There is still no explanation about the threshold value of enamel mineral solubility and the occurance of dental erosion after consuming acidic soft drink. Purpose: This research is aimed to find the threshold value of enamel mineral solubility and dental erosion before and after consuming acidic soft drinks. Methods: Subjects of the research are saliva and enamel of 12 rabbits, which have some criteria such as age > 70 days, body weight > 600 grams, and teeth considered to be healthy. The sample devided equally into 4 groups. Each of those marmooths was given a drink as much as 2.5 cc/consumption (there are 1, 2 and 3× per day by using syringe without injection needle. Salivary minerals then were examined by using atomic absorption spectrophotometric (ASS, while dental erosion was examined using scanning electron microscop (SEM. The data were analyzed by using Paired t-test. Results: It is known that the threshold value of enamel mineral solubility (K, Na, Fe, Mg, Cl, P, Ca, F, C has significant difference (p < 0.05 after being exposed to folic acid. Meanwhile, Fe did not have significant difference (p = 0.090 after being exposed to citric acid. Similarly, C did not have significant difference (p = 0.063 after being exposed to bicarbonate acid. Furthermore, it is also known that the threshold time value of dental erosion are on the 105th day for folic acid, on the 111th day for citric acid, and on the 117th day for bicarbonate acid. Conclusion: Threshold value of enamel mineral solubility before and after consuming soft drinks containing acid is different. Based on the threshold value of dental erosion, it is known that folic acid is the most erosive acid.Latar belakang: Erosi gigi bersifat irreversible

Utilization of Low-Cost Ellagitannins for Ellagic Acid Production and Antimicrobial Phenolics Enhancing By Aspergillus awamorii and Aspergillus oryzae

International Nuclear Information System (INIS)

El-Bialy, H.A.; Abd EL-Aziz, A.B.

2009-01-01

Three fungal strains, Aspergillus awamorii A 9 , Aspergillus awamorii A 2 3 and Aspergillus oryzae O 2 , were selected out of ten fungal strains for their activeness in converting pomegranate peel ellagitannins into ellagic acid. When pomegranate peel was fermented by Aspergillus awamorii A 9 , the highest yields of ellagic acid (7.93±0.23 mg/g solid substrate) and total soluble phenolics (14.61±0.36 mg/g solid substrate) were produced at 5 and 10 days of incubation, respectively. Also, blue berry pomace, red grape pomace, strawberry pomace were evaluated as low cost ellagitannin sources for ellagic acid and soluble phenolics production. The antimicrobial activity of soluble phenolics extracted from fermented pomegranate peel and strawberry pomace was tested against two food-borne pathogens (Escherichia coli and Salmonella typhimurium). This study also revealed that 3 kGy enhanced the activity of antimicrobial phenolics

[*C]octanoic acid breath test to measure gastric emptying rate of solids.

Science.gov (United States)

Maes, B D; Ghoos, Y F; Rutgeerts, P J; Hiele, M I; Geypens, B; Vantrappen, G

1994-12-01

We have developed a breath test to measure solid gastric emptying using a standardized scrambled egg test meal (250 kcal) labeled with [14C]octanoic acid or [13C]octanoic acid. In vitro incubation studies showed that octanoic acid is a reliable marker of the solid phase. The breath test was validated in 36 subjects by simultaneous radioscintigraphic and breath test measurements. Nine healthy volunteers were studied after intravenous administration of 200 mg erythromycin and peroral administration of 30 mg propantheline, respectively. Erythromycin significantly enhanced gastric emptying, while propantheline significantly reduced gastric emptying rates. We conclude that the [*C]octanoic breath test is a promising and reliable test for measuring the gastric emptying rate of solids.

A Systematic Study of Molecular Interactions of Anionic Drugs with a Dimethylaminoethyl Methacrylate Copolymer Regarding Solubility Enhancement.

Science.gov (United States)

Saal, Wiebke; Ross, Alfred; Wyttenbach, Nicole; Alsenz, Jochem; Kuentz, Martin

2017-04-03

The methacrylate-copolymer Eudragit EPO (EPO) has raised interest in solubility enhancement of anionic drugs. Effects on aqueous drug solubility at rather low polymer concentrations are barely known despite their importance upon dissolution and dilution of oral dosage forms. We provide evidence for substantial enhancement (factor 4-230) of aqueous solubility of poorly water-soluble anionic drugs induced by low (0.1-5% (w/w)) concentration of EPO for a panel of seven acidic crystalline drugs. Diffusion data (determined by 1 H nuclear magnetic resonance spectroscopy) indicate that the solubility increasing effect monitored by quantitative ultraperformance liquid chromatography was caused primarily by molecular API polymer interactions in the bulk liquid phase. Residual solid API remained unaltered as tested by X-ray powder diffraction. The solubility enhancement (SE) revealed a significant rank correlation (r Spearman = -0.83) with rDiff API , where SE and rDiff API are defined ratios of solubility and diffusion coefficient in the presence and absence of EPO. SE decreased in the order of indomethacin, mefenamic acid, warfarin, piroxicam, furosemide, bezafibrate, and tolbutamide. The solubilizing effect was attributed to both ionic and hydrophobic interactions between drugs and EPO. The excellent solubilizing properties of EPO are highly promising for pharmaceutical development, and the data set provides first steps toward an understanding of drug-excipient interaction mechanisms.

Biowaiver monograph for immediate-release solid oral dosage forms: acetylsalicylic acid.

Science.gov (United States)

Dressman, Jennifer B; Nair, Anita; Abrahamsson, Bertil; Barends, Dirk M; Groot, D W; Kopp, Sabine; Langguth, Peter; Polli, James E; Shah, Vinod P; Zimmer, Markus

2012-08-01

A biowaiver monograph for acetylsalicylic acid (ASA) is presented. Literature and experimental data indicate that ASA is a highly soluble and highly permeable drug, leading to assignment of this active pharmaceutical ingredient (API) to Class I of the Biopharmaceutics Classification System (BCS). Limited bioequivalence (BE) studies reported in the literature indicate that products that have been tested are bioequivalent. Most of the excipients used in products with a marketing authorization in Europe are not considered to have an impact on gastrointestinal motility or permeability. Furthermore, ASA has a wide therapeutic index. Thus, the risks to the patient that might occur if a nonbioequivalent product were to be incorrectly deemed bioequivalent according to the biowaiver procedure appear to be minimal. As a result, the BCS-based biowaiver procedure can be recommended for approval of new formulations of solid oral dosage forms containing ASA as the only API, including both multisource and reformulated products, under the following conditions: (1) excipients are chosen from those used in ASA products already registered in International Conference on Harmonization and associated countries and (2) the dissolution profiles of the test and the comparator products comply with the BE guidance. Copyright © 2012 Wiley Periodicals, Inc.

Forensic Discrimination of Concrete Pieces by Elemental Analysis of Acid-soluble Component with Inductively Coupled Plasma-Mass Spectrometry.

Science.gov (United States)

Kasamatsu, Masaaki; Igawa, Takao; Suzuki, Shinichi; Suzuki, Yasuhiro

2018-01-01

Since fragments of concrete can be evidence of crime, a determination of whether or not they come from the same origin is required. The authors focused on nitric acid-soluble components in the fragments of concrete. As a result of qualitative analysis with ICP-MS, it was confirmed that elements such as Cu, Zn, Rb, Sr, Zr, Ba, La, Ce, Nd, and Pb were contained in the fragments. After the nitric acid-soluble components in the fragments of concrete were separated by dissolving them in nitric acid, the concentrations of these elements in the dissolved solution were quantitatively determined by ICP-MS. The concentration ratios of nine elements compared to La were used as indicators. By comparing these indicators, it was possible to discriminate between the fragments of concrete.

Aqueous Microwave-Assisted Solid-Phase Synthesis Using Boc-Amino Acid Nanoparticles

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Yoshinobu Fukumori

2013-07-01

Full Text Available We have previously developed water-based microwave (MW-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles.

Solubility and hydrolysis of Np(V) in dilute to concentrated alkaline NaCl solutions. Formation of Na-Np(V)-OH solid phases at 22 C

Energy Technology Data Exchange (ETDEWEB)

Petrov, Vladimir G. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; Fellhauer, David; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Altmaier, Marcus [Karlsruhe Institute of Technology (Germany). Inst. for Nuclear Waste Disposal; Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; NRC Kurchatov Institute, Moscow (Russian Federation)

2017-03-01

The solubility of Np(V) was investigated at T=22±2 C in alkaline NaCl solutions of different ionic strength (0.1-5.0 M). The solid phases controlling the solubility at different -log{sub 10} m{sub H{sup +}}(pH{sub m}) and NaCl concentration were characterized by XRD, quantitative chemical analysis, SEM-EDS and XAFS (both XANES and EXAFS). Aqueous phases in equilibrium with Np(V) solids were investigated for selected samples within 8.9≤pH{sub m}≤10.3 by UV-vis/NIR absorption spectroscopy. In 0.1 M NaCl, the experimental solubility of the initial greenish NpO{sub 2}OH(am) solid phase is in good agreement with previous results obtained in NaClO{sub 4} solutions, and is consistent with model calculations for fresh NpO{sub 2}OH(am) using the thermodynamic data selection in NEA-TDB. Below pH{sub m}∝11.5 and for all NaCl concentrations studied, Np concentration in equilibrium with the solid phase remained constant during the timeframe of this study (∝2 years). This observation is in contrast to the aging of the initial NpO{sub 2}OH(am) into a more crystalline modification with the same stoichiometry, NpO{sub 2}OH(am, aged), as reported in previous studies for concentrated NaClO{sub 4} and NaCl. Instead, the greenish NpO{sub 2}OH(am) transforms into a white solid phase in those systems with [NaCl]≥1.0 M and pH{sub m}≥11.5, and into two different pinkish phases above pH{sub m}∝13.2. The solid phase transformation is accompanied by a drop in Np solubility of 0.5-2 log{sub 10}-units (depending upon NaCl concentration). XANES analyses of green, white and pink phases confirm the predominance of Np(V) in all cases. Quantitative chemical analysis shows the incorporation of Na{sup +} in the original NpO{sub 2}OH(am) material, with Na:Np ≤ 0.3 for the greenish solids and 0.8 ≤ Na:Np ≤ 1.6 for the white and pinkish phases. XRD data confirms the amorphous character of the greenish phase, whereas white and pink solids show well-defined but discrepant XRD patterns

Investigation of solid-phase hydrogenation of amino acids and peptides

International Nuclear Information System (INIS)

Zolotarev, Yu.A.; Myasoedov, N.F.; Zajtsev, D.A.; Lubnin, M.Yu.; Tatur, V.Yu.; Kozik, V.S.; Dorokhova, E.M.; Rozenberg, S.N.

1990-01-01

The possibility of synthesizing amino acids and peptides multiply labelled with tritium or deuterium by the method of solid-phase isotopic exchange with gaseous hydrogen isotopes was verified. Establishment of the isotopic hydrogen equilibrium between the gaseous phase and the solid phase formed by the amino acid molecules was found experimentally. The activation energy of the isotopic exchange is 13 kcal/mol. A mathematical model was set up for the isotopic exchange with a probable substitution of hydrogen atoms. Uniformly labelled amino acids were obtained in a high optical purity and with 80 to 90% hydrogen substitution by deuterium and tritium. Tritiated peptides were prepared in high yields at molar activities of 1.5 to 3.7 TBq/mmol. (author). 4 tabs

Structural and solubility parameter correlations of gelation abilities for dihydroxylated derivatives of long-chain, naturally occurring fatty acids.

Science.gov (United States)

Zhang, Mohan; Selvakumar, Sermadurai; Zhang, Xinran; Sibi, Mukund P; Weiss, Richard G

2015-06-01

Creating structure-property correlations at different distance scales is one of the important challenges to the rational design of molecular gelators. Here, a series of dihydroxylated derivatives of long-chain fatty acids, derived from three naturally occurring molecules-oleic, erucic and ricinoleic acids-are investigated as gelators of a wide variety of liquids. Conclusions about what constitutes a more (or less!) efficient gelator are based upon analyses of a variety of thermal, structural, molecular modeling, and rheological results. Correlations between the manner of molecular packing in the neat solid or gel states of the gelators and Hansen solubility data from the liquids leads to the conclusion that diol stereochemistry, the number of carbon atoms separating the two hydroxyl groups, and the length of the alkanoic chains are the most important structural parameters controlling efficiency of gel formation for these gelators. Some of the diol gelators are as efficient or even more efficient than the well-known, excellent gelator, (R)-12-hydroxystearic acid; others are much worse. The ability to form extensive intermolecular H-bonding networks along the alkyl chains appears to play a key role in promoting fiber growth and, thus, gelation. In toto, the results demonstrate how the efficiency of gelation can be modulated by very small structural changes and also suggest how other structural modifications may be exploited to create efficient gelators. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The solubilities of significant organic compounds in HLW tank supernate solutions -- FY 1995 progress report

International Nuclear Information System (INIS)

Barney, G.S.

1996-01-01

At the Hanford Site organic compounds were measured in tank supernate simulant solutions during FY 1995. This solubility information will be used to determine if these organic salts could exist in solid phases (saltcake or sludges) in the waste where they might react violently with the nitrate or nitrite salts present in the tanks. Solubilities of sodium glycolate, succinate, and caproate salts; iron and aluminum and butylphosphate salts; and aluminum oxalate were measured in simulated waste supernate solutions at 25 degree C, 30 degree C, 40 degree C, and 50 degree C. The organic compounds were selected because they are expected to exist in relatively high concentrations in the tanks. The solubilities of sodium glycolate, succinate, caproate, and butylphosphate in HLW tank supernate solutions were high over the temperature and sodium hydroxide concentration ranges expected in the tanks. High solubilities will prevent solid sodium salts of these organic acids from precipitating from tank supernate solutions. The total organic carbon concentrations (YOC) of actual tank supernates are generally much lower than the TOC ranges for simulated supernate solutions saturated (at the solubility limit) with the organic salts. This is so even if all the dissolved carbon in a given tank and supernate is due to only one of these eight soluble compounds (an unlikely situation). Metal ion complexes of and butylphosphate and oxalate in supernate solutions were not stable in the presence of the hydroxide concentrations expected in most tanks. Iron and aluminum dibutylphosphate compounds reacted with hydroxide to form soluble sodium dibutylphosphate and precipitated iron and aluminum hydroxides. Aluminum oxalate complexes were also not stable in the basic simulated supernate solutions. Solubilities of all the organic salts decrease with increasing sodium hydroxide concentration because of the common ion effect of Na+. Increasing temperatures raised the solubilities of the organic

A novel osmotic pump-based controlled delivery system consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen: in vitro and in vivo evaluation.

Science.gov (United States)

Li, Shujuan; Wang, Xiaoyu; Wang, Yingying; Zhao, Qianqian; Zhang, Lina; Yang, Xinggang; Liu, Dandan; Pan, Weisan

2015-01-01

In this study, a novel controlled release osmotic pump capsule consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen (FP) was developed to improve the solubility and oral bioavailability of FP and to minimize the fluctuation of plasma concentration. The pH-modulated solid dispersion containing FP, Kollidon® 12 PF and Na2CO3 at a weight ratio of 1/4.5/0.02 was prepared using the solvent evaporation method. The osmotic pump capsule was assembled by semi-permeable capsule shell of cellulose acetate (CA) prepared by the perfusion method. Then, the solid dispersion, penetration enhancer, and suspending agents were tableted and filled into the capsule. Central composite design-response surface methodology was used to evaluate the influence of factors on the responses. A second-order polynomial model and a multiple linear model were fitted to correlation coefficient of drug release profile and ultimate cumulative release in 12 h, respectively. The actual response values were in good accordance with the predicted ones. The optimized formulation showed a complete drug delivery and zero-order release rate. Beagle dogs were used to be conducted in the pharmacokinetic study. The in vivo study indicated that the relative bioavailability of the novel osmotic pump system was 133.99% compared with the commercial preparation. The novel controlled delivery system with combination of pH-modulated solid dispersion and osmotic pump system is not only a promising strategy to improve the solubility and oral bioavailability of poorly soluble ionizable drugs but also an effective way to reduce dosing frequency and minimize the plasma fluctuation.

Influence of cold stress on contents of soluble sugars, vitamin C and free amino acids including gamma-aminobutyric acid (GABA) in spinach (Spinacia oleracea).

Science.gov (United States)

Yoon, Young-Eun; Kuppusamy, Saranya; Cho, Kye Man; Kim, Pil Joo; Kwack, Yong-Bum; Lee, Yong Bok

2017-01-15

The contents of soluble sugars (sucrose, fructose, glucose, maltose and raffinose), vitamin C and free amino acids (34 compounds, essential and non-essential) were quantified in open-field and greenhouse-grown spinaches in response to cold stress using liquid chromatography. In general, greenhouse cultivation produced nutritionally high value spinach in a shorter growing period, where the soluble sugars, vitamin C and total amino acids concentrations, including essential were in larger amounts compared to those grown in open-field scenarios. Further, low temperature exposure of spinach during a shorter growth period resulted in the production of spinach with high sucrose, ascorbate, proline, gamma-aminobutyric acid, valine and leucine content, and these constitute the most important energy/nutrient sources. In conclusion, cultivation of spinach in greenhouse at a low temperature (4-7°C) and exposure for a shorter period (7-21days) before harvest is recommended. This strategy will produce a high quality product that people can eat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solid-state actinide acid phosphites from phosphorous acid melts

International Nuclear Information System (INIS)

Oh, George N.; Burns, Peter C.

2014-01-01

The reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )]. This compound crystallizes in space group P2 1 /n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O)·2(H 2 O). α- and β-An(HPO 2 OH) 4 crystallize in space groups C2/c and P2 1 /n, respectively, and comprise a three-dimensional network of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) crystallizes in a layered structure in space group Pbca that is composed of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with DMF produces crystals of (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) with a layered structure. - Highlights: • U(VI), U(IV) and Th(IV) phosphites were synthesized by solution

Influence of the microwave technology on solid dispersions of mefenamic acid and flufenamic acid.

Directory of Open Access Journals (Sweden)

Sultan Alshehri

Full Text Available The present studies were undertaken to develop solvent-free solid dispersions (SDs for poorly soluble anti-inflammatory drugs mefenamic acid (MA and flufenamic acid (FFA in order to enhance their in vitro dissolution rate and in vivo anti-inflammatory effects. The SDs of MA and FFA were prepared using microwaves irradiation (MW technique. Different carriers such as Pluronic F127® (PL, Eudragit EPO® (EPO, polyethylene glycol 4000 (PEG 4000 and Gelucire 50/13 (GLU were used for the preparation of SDs. Prepared MW irradiated SDs were characterized physicochemically using differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, Fourier transform infra-red (FT-IR spectroscopy, powder X-ray diffraction (PXRD and scanning electron microscopy (SEM. The physicochemical characteristics and drug release profile of SDs were compared with pure drugs. The results of DSC, TGA, FT-IR, PXRD and SEM showed that SDs were successfully prepared. In vitro dissolution rate of MA and FFA was remarkably enhanced by SDs in comparison with pure MA and FFA. The SDs of MA and FFA prepared using PEG 400 showed higher drug release profile in comparison with those prepared using PL, EPO or GLU. The dissolution efficiency for MA-PEG SD and FFA-PEG SD was obtained as 61.40 and 59.18%, respectively. Optimized SDs were also evaluated for in vivo anti-inflammatory effects in male Wistar rats. The results showed significant % inhibition by MA-PEG (87.74% after 4 h and FFA-PEG SDs (81.76% after 4 h in comparison with pure MA (68.09% after 4 h and pure FFA (55.27% after 4 h (P<0.05. These results suggested that MW irradiated SDs of MA and FFA could be successfully used for the enhancement of in vitro dissolution rate and in vivo therapeutic efficacy of both drugs.

Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

Science.gov (United States)

Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

2016-05-01

Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed.

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition.

Science.gov (United States)

Nakayama, Hirokazu; Hayashi, Aki

2014-07-30

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

Directory of Open Access Journals (Sweden)

Hirokazu Nakayama

2014-07-01

Full Text Available The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

Synthesis and photophysicochemical studies of a water soluble conjugate between folic acid and zinc tetraaminophthalocyanine

International Nuclear Information System (INIS)

Khoza, Phindile; Antunes, Edith; Chen, Ji-Yao; Nyokong, Tebello

2013-01-01

This work reports on the synthesis of zinc tetraaminophthalocyanine (ZnTAPc) functionalized with folic acid (FA), forming ZnTAPcFA. The conjugate between FA and ZnTAPc was soluble in water whereas ZnTAPc alone is not. The structure of ZnTAPcFA conjugate was elucidated by 1 H NMR, MALDI-TOF mass and FTIR spectra. Photophysical and photochemical studies of ZnTAPcFA were conducted in DMSO. The increase in fluorescence quantum yield of the conjugate was accompanied by a decrease in the triplet and singlet oxygen quantum yields. The changes in triplet quantum and singlet oxygen quantum yields were marginal when ZnTAPc was simply mixed with FA without a chemical bond. - Highlights: ► A conjugate between folic acid and a zinc tetraaminophthalocyanine was formed. ► The conjugate is water soluble even though the phthalocyanine alone is not. ► The fluorescence quantum yield of the conjugate was enhanced compared to the phthalocyanine alone. ► Triplet quantum yields decreased for the conjugate

Effect of water soluble carrier on dissolution profiles of diclofenac sodium.

Science.gov (United States)

Cwiertnia, Barbara

2013-01-01

Pharmaceutical aviailability of diclofenac sodium from solid dispersions of PEG 6000 have been studied in comparison to those of the corresponding physical mixtures and pure diclofenac sodium. The diclofenac sodium is poorly water soluble drug. The properties of diclofenac sodium-PEG 6000 solid dispersions have been determined by the methods of differential scanning calorimetry (DSC), X-ray diffraction and scanning electron microscopy (SEM). The effect of PEG 6000 on the solubility of selected diclofenac sodium dispersions has been studied. The solubility of diclofenac sodium from its solid dispersion has been found to increase in the presence of PEG 6000.

Advantageous Solubility-Permeability Interplay When Using Amorphous Solid Dispersion (ASD) Formulation for the BCS Class IV P-gp Substrate Rifaximin: Simultaneous Increase of Both the Solubility and the Permeability.

Science.gov (United States)

Beig, Avital; Fine-Shamir, Noa; Lindley, David; Miller, Jonathan M; Dahan, Arik

2017-05-01

Rifaximin is a BCS class IV (low-solubility, low-permeability) drug and also a P-gp substrate. The aims of this work were to assess the efficiency of different rifaximin amorphous solid dispersion (ASDs) formulations in achieving and maintaining supersaturation and to investigate the consequent solubility-permeability interplay. Spray-dried rifaximin ASDs were prepared with different hydrophilic polymers and their ability to achieve and maintain supersaturation was assessed. Then, rifaximin's apparent intestinal permeability was investigated as a function of increasing supersaturation both in vitro using the parallel artificial membrane permeability assay (PAMPA) and in vivo using the single-pass rat intestinal perfusion (SPIP) model. The efficiency of the different ASDs to achieve and maintain supersaturation of rifaximin was found to be highly polymer dependent, and the copovidone/HPC-SL formulation was found to be superior to the other two, allowing supersaturation of 200× that of the crystalline solubility for 20 h. In vitro, rifaximin flux was increased and the apparent permeability was constant as a function of increasing supersaturation level. In vivo, on the other hand, absorption rate coefficient (k a ) was first constant as a function of increasing supersaturation, but at 250×, the crystalline solubility k a was doubled, similar to the k a in the presence of the strong P-gp inhibitor GF120918. In conclusion, a new and favorable nature of solubility-permeability interplay was revealed in this work: delivering high supersaturation level of the BCS class IV drug rifaximin via ASD, thereby saturating the drugs' P-gp-mediated efflux transport, led to the favorable unique win-win situation, where both the solubility and the permeability increased simultaneously.

Microwave-induced facile synthesis of water-soluble fluorogenic alginic acid derivatives.

Science.gov (United States)

Chhatbar, Mahesh U; Meena, Ramavatar; Prasad, Kamalesh; Chejara, Dharmesh R; Siddhanta, A K

2011-04-01

A facile microwave-induced method was developed for synthesizing water-soluble fluorescent derivatives of alginic acid (ALG) with four different diamines, hydrazine (HY), ethylenediamine (EDA), 1,6-hexanediamine (HDA), and 1,4-cyclohexanediamine (CHDA), followed by a cross-linking reaction with a natural cross linker genipin. The ethylenediamine derivative of alginic acid (ALG-EDA) exhibited good fluorescent activity, which upon cross linking was enhanced threefold. The other amide derivatives, for example, ALG-HY, ALG-HDA, and ALG-CHDA, were not fluorescent, but their respective crosslinked products exhibited excellent fluorescent activity. The fluorescence intensity had an inverse correlation with the number of carbon atoms present in the amine, which in turn was a function of degree of substitution (DS). These fluorescent polysaccharide derivatives are of potential utility in the domain of sensor applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Acid transformation of bauxite residue: Conversion of its alkaline characteristics.

Science.gov (United States)

Kong, Xiangfeng; Li, Meng; Xue, Shengguo; Hartley, William; Chen, Chengrong; Wu, Chuan; Li, Xiaofei; Li, Yiwei

2017-02-15

Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Production of Citric Acid from Solid State Fermentation of Sugarcane ...

African Journals Online (AJOL)

Aspergillus niger is the leading microorganism of choice for citric acid production. Sugarcane waste was used as substrate under solid state fermentation to comparatively evaluate the citric acid production capacity of Aspergillus niger isolates and the indigenous microflora in the sugarcane waste. Known optimal cultural ...

Fluorescence quenching behaviour of uric acid interacting with water-soluble cationic porphyrin

International Nuclear Information System (INIS)

Makarska-Bialokoz, Magdalena; Borowski, Piotr

2015-01-01

The process of association between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H 2 TTMePP) and uric acid as well as its sodium salt has been studied in aqueous NaOH solution analysing its absorption and steady-state fluorescence spectra. The fluorescence quenching effect observed during interactions porphyrin-uric acid compounds points at the fractional accessibility of the fluorophore for the quencher. The association and fluorescence quenching constants are of the order of magnitude of 10 5 mol −1 . The fluorescence lifetimes and the quantum yields of the porphyrin anionic form were established. The results demonstrate that uric acid and its sodium salt can interact with H 2 TTMePP at basic pH and through formation of stacking complexes are able to quench its ability to emission. - Highlights: • Association study of water soluble cationic porphyrin with uric acid. • Porphyrin absorption spectra undergo the bathochromic and hypochromic effects. • Uric acid interacts with porphyrin in inhibiting manner, quenching its emission. • Fluorescence quenching effect testifies for the partial inactivation of a porphyrin. • The association and fluorescence quenching constants were calculated

Fluorescence quenching behaviour of uric acid interacting with water-soluble cationic porphyrin

Energy Technology Data Exchange (ETDEWEB)

Makarska-Bialokoz, Magdalena, E-mail: makarska@hektor.umcs.lublin.pl [Department of Inorganic Chemistry, Maria Curie-Sklodowska University M. C. Sklodowska Sq. 2, 20-031 Lublin (Poland); Borowski, Piotr [Faculty of Chemistry, Maria Curie-Sklodowska University M. C. Sklodowska Sq. 3, 20-031 Lublin (Poland)

2015-04-15

The process of association between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H{sub 2}TTMePP) and uric acid as well as its sodium salt has been studied in aqueous NaOH solution analysing its absorption and steady-state fluorescence spectra. The fluorescence quenching effect observed during interactions porphyrin-uric acid compounds points at the fractional accessibility of the fluorophore for the quencher. The association and fluorescence quenching constants are of the order of magnitude of 10{sup 5} mol{sup −1}. The fluorescence lifetimes and the quantum yields of the porphyrin anionic form were established. The results demonstrate that uric acid and its sodium salt can interact with H{sub 2}TTMePP at basic pH and through formation of stacking complexes are able to quench its ability to emission. - Highlights: • Association study of water soluble cationic porphyrin with uric acid. • Porphyrin absorption spectra undergo the bathochromic and hypochromic effects. • Uric acid interacts with porphyrin in inhibiting manner, quenching its emission. • Fluorescence quenching effect testifies for the partial inactivation of a porphyrin. • The association and fluorescence quenching constants were calculated.

Differences in fluorescence characteristics and bioavailability of water-soluble organic matter (WSOM) in sediments and suspended solids in Lihu Lake, China.

Science.gov (United States)

Wang, Wenwen; Wang, Shuhang; Jiang, Xia; Zheng, Binghui; Zhao, Li; Zhang, Bo; Chen, Junyi

2018-05-01

The spectral characteristics, spatial distribution, and bioavailability of water-soluble organic matter (WSOM) in suspended solids and surface sediments of Lihu Lake, China, were investigated through excitation-emission matrix spectra and parallel factor analysis. The average content of dissolved organic carbon (DOC) in the sediments reached 643.28 ± 58.34 mg C/kg and that in suspended solids was 714.87 ± 69.24 mg C/kg. The fluorescence intensity of WSOM totaled 90.87 ± 5.65 and 115.42 ± 8.02 RU/g for the sediments and suspended solids, respectively. The DOC and fluorescence intensity of the WSOM showed an increasing trend moving from the west to the east of the lake. The WSOM in sediments and suspended solids contained two humic-like (C1 and C2) and one tryptophan-like (C3) components. These components had different fluorescent peaks and relative proportions. In the sediments, the relative proportions of C1, C2, and C3 were 33.71% ± 0.71, 26.83% ± 0.68, and 39.50% ± 0.71%, respectively. Meanwhile, C1 (35.77 ± 0.84%), C2 (34.07 ± 0.61%), and C3 (30.16 ± 0.75%) had similar relative percentages in suspended solids. The sediments had a lower humification index (3.02 ± 0.08) than the suspended solids (4.04 ± 0.15). Exchangeable nitrogen for the sediments and suspended solids was dominated by exchangeable ammonium nitrogen and soluble organic nitrogen, respectively. WSOM plays an important role in migration and transformation of nitrogen in sediments and suspended solids. The sediment-derived WSOM exhibited higher lability and biological activity than did the suspended solid-derived WSOM. The relative ratio of the intensity of protein-like fluorescent component to that of the humic-like one can be used as a reference index to evaluate the lability and biological activity of WSOM in sediments and suspended solids.

Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase.

Science.gov (United States)

Oguro, Ami; Imaoka, Susumu

2012-03-01

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hydrolyzed products. Although lecithin itself did not inhibit the phosphatase activity, the hydrolyzed lecithin significantly inhibited it, suggesting that lysophospholipid or fatty acid can inhibit it. Next, we investigated the inhibition of phosphatase activity by lysophosphatidyl choline, palmitoyl lysophosphatidic acid, monopalmitoyl glycerol, and palmitic acid. Palmitoyl lysophosphatidic acid and fatty acid efficiently inhibited phosphatase activity, suggesting that lysophosphatidic acids (LPAs) are substrates for the phosphatase activity of sEH. As expected, palmitoyl, stearoyl, oleoyl, and arachidonoyl LPAs were efficiently dephosphorylated by sEH (Km, 3-7 μM; Vmax, 150-193 nmol/min/mg). These results suggest that LPAs are substrates of sEH, which may regulate physiological functions of cells via their metabolism.

Formation and filtration characteristics of solids generated in a high level liquid waste treatment process. Solids formation behavior from simulated high level liquid waste

International Nuclear Information System (INIS)

Kondo, Y.; Kubota, M.

1997-01-01

The solids formation behavior in a simulated high level liquid waste (HLLW) was experimentally examined, when the simulated HLLW was treated in the ordinary way of actual HLLW treatment process. Solids formation conditions and mechanism were closely discussed. The solids formation during a concentration step can be explained by considering the formation of zirconium phosphate, phosphomolybdic acid and precipitation of strontium and barium nitrates and their solubilities. For the solids formation during the denitration step, at least four courses were observed; formation of an undissolved material by a chemical reaction with each other of solute elements (zirconium, molybdenum, tellurium) precipitation by reduction (platinum group metals) formation of hydroxide or carbonate compounds (chromium, neodymium, iron, nickel, strontium, barium) and a physical adsorption to stable solid such as zirconium molybdate (nickel, strontium, barium). (author)

Highly thermal-stable and functional cellulose nanocrystals and nanofibrils produced using fully recyclable organic acids

Science.gov (United States)

Liheng Chen; Junyong Zhu; Carlos Baez; Peter Kitin; Thomas Elder

2016-01-01

Here we report the production of highly thermal stable and functional cellulose nanocrystals (CNC) and nanofibrils (CNF) by hydrolysis using concentrated organic acids. Due to their low water solubility, these solid organic acids can be easily recovered after hydrolysis reactions through crystallization at a lower or ambient temperature. When dicarboxylic acids were...

Synthesis and solubility measurement in supercritical carbon dioxide of two solid derivatives of 2-methylnaphthalene-1,4-dione (menadione): 2-(Benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione

International Nuclear Information System (INIS)

Zacconi, Flavia C.; Nuñez, Olga N.; Cabrera, Adolfo L.; Valenzuela, Loreto M.

2016-01-01

Highlights: • Two menadione derivatives were synthesized, purified and characterized. • Solubility of menadione derivatives in SC-CO 2 was measured at T < 333 K, p < 28 MPa. • Thermodynamic consistency of solubility data measured was evaluated. • Solubility data was correlated in terms of temperature and CO 2 density. - Abstract: Synthesis of two solid derivatives of vitamin K 3 (2-methylnaphthalene-1,4-dione or menadione), 2-(benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione was completed using a 1,4 Michael addition reaction at 323 K in an inert atmosphere, with reaction yields of 62% mol·mol −1 and 71% mol·mol −1 , respectively, and a purity grade of 98% mol·mol −1 for each component. Isothermal solubility (mole fraction) of each solid derivative in supercritical carbon dioxide was performed using an analytic-recirculation methodology, with direct determination of the molar composition of the carbon dioxide-rich phase by using high performance liquid chromatography, at temperatures of (313, 323 and 333) K and pressures from (8–28) MPa. Results indicated that the range of measured solubilities were from (59 × 10 −6 to 368 × 10 −6 ) mol·mol −1 for solid 2-(benzylamino)-3-methylnaphthalene-1,4-dione and from (40 × 10 −6 to 205 × 10 −6 ) mol·mol −1 for solid 3-(phenethylamino)-2-methylnaphthalene-1,4-dione. The experimental solubility was validated using three approaches, estimating the combined expanded uncertainty of measurement for each solubility data point, evaluating the thermodynamic consistency of the data utilizing a test based on the Gibbs–Duhem equation, and verifying the self-consistency by correlating the experimental solubility values with a semi-empirical model as a function of temperature, pressure and pure carbon dioxide density.

Sialic Acid Binding Properties of Soluble Coronavirus Spike (S1 Proteins: Differences between Infectious Bronchitis Virus and Transmissible Gastroenteritis Virus

Directory of Open Access Journals (Sweden)

Christine Winter

2013-07-01

Full Text Available The spike proteins of a number of coronaviruses are able to bind to sialic acids present on the cell surface. The importance of this sialic acid binding ability during infection is, however, quite different. We compared the spike protein of transmissible gastroenteritis virus (TGEV and the spike protein of infectious bronchitis virus (IBV. Whereas sialic acid is the only receptor determinant known so far for IBV, TGEV requires interaction with its receptor aminopeptidase N to initiate infection of cells. Binding tests with soluble spike proteins carrying an IgG Fc-tag revealed pronounced differences between these two viral proteins. Binding of the IBV spike protein to host cells was in all experiments sialic acid dependent, whereas the soluble TGEV spike showed binding to APN but had no detectable sialic acid binding activity. Our results underline the different ways in which binding to sialoglycoconjugates is mediated by coronavirus spike proteins.

Solid Acid-Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR-IR Spectroscopy

NARCIS (Netherlands)

Zakzeski, J.; Grisel, R.J.H.; Smit, A.T.; Weckhuysen, B.M.

2012-01-01

The solid acid-catalyzed hydrolysis of cellulose was studied under elevated temperatures and autogenous pressures using in situ ATR-IR spectroscopy. Standards of cellulose and pure reaction products, which include glucose, fructose, hydroxymethylfurfural (HMF), levulinic acid (LA), formic acid, and

pH-dependent solubility of indomethacin-saccharin and carbamazepine-saccharin cocrystals in aqueous media.

Science.gov (United States)

Alhalaweh, Amjad; Roy, Lilly; Rodríguez-Hornedo, Naír; Velaga, Sitaram P

2012-09-04

Cocrystals constitute an important class of pharmaceutical solids for their remarkable ability to modulate solubility and pH dependence of water insoluble drugs. Here we show how cocrystals of indomethacin-saccharin (IND-SAC) and carbamazepine-saccharin (CBZ-SAC) enhance solubility and impart a pH-sensitivity different from that of the drugs. IND-SAC exhibited solubilities 13 to 65 times higher than IND at pH values of 1 to 3, whereas CBZ-SAC exhibited a 2 to 10 times higher solubility than CBZ dihydrate. Cocrystal solubility dependence on pH predicted from mathematical models using cocrystal K(sp), and cocrystal component K(a) values, was in excellent agreement with experimental measurements. The cocrystal solubility increase relative to drug was predicted to reach a limiting value for a cocrystal with two acidic components. This limiting value is determined by the ionization constants of cocrystal components. Eutectic constants are shown to be meaningful indicators of cocrystal solubility and its pH dependence. The two contributions to solubility, cocrystal lattice and solvation, were evaluated by thermal and solubility determinations. The results show that solvation is the main barrier for the aqueous solubility of these drugs and their cocrystals, which are orders of magnitude higher than their lattice barriers. Cocrystal increase in solubility is thus a result of decreasing the solvation barrier compared to that of the drug. This work demonstrates the favorable properties of cocrystals and strategies that facilitate their meaningful characterization.

The effects of disordered structure on the solubility and dissolution rates of some hydrophilic, sparingly soluble drugs.

Science.gov (United States)

Mosharraf, M; Sebhatu, T; Nyström, C

1999-01-15

The effects of experimental design on the apparent solubility of two sparingly soluble hydrophilic compounds (barium sulphate and calcium carbonate) were studied in this paper. The apparent solubility appeared to be primarily dependent on the amount of solute added to the solvent in each experiment, increasing with increased amounts. This effect seems to be due to the existence of a peripheral disordered layer. However physico-chemical methods used in the present study were not able to unambiguously verify the existence of any disorder in the solid state structure of the drugs. At higher proportions of solute to solvent, the solubility reached a plateau corresponding to the solubility of the disordered or amorphous molecular form of the material. Milling the powders caused the plateau to be reached at lower proportions of solute to solvent, since this further disordered the surface of the drug particles. It was also found that the apparent solubility of the drugs tested decreased after storage at high relative humidities. A model for describing the effects of a disordered surface layer of varying thickness and continuity on the solubility of a substance is presented. This model may be used as a method for detection of minute amount of disorder, where no other technique is capable of detecting the disordered structure. It is suggested that recrystallisation of the material occurs via slow solid-state transition at the surface of the drug particle; this would slowly reduce the apparent solubility of the substance at the plateau level to the thermodynamically stable value. A biphasic dissolution rate profile was obtained. The solubility of the disordered surface of the particles appeared to be the rate-determining factor during the initial dissolution phase, while the solubility of the crystalline core was the rate-determining factor during the final slower phase.

Impact of solid state fermentation on nutritional, physical and flavor properties of wheat bran.

Science.gov (United States)

Zhao, Hui-Min; Guo, Xiao-Na; Zhu, Ke-Xue

2017-02-15

To improve the nutritional, physical and flavor properties of wheat bran, yeast and lactic acid bacteria (LAB) were used for fermenting wheat bran in solid state. Appearance properties, nutritional properties, microstructure, hydration properties and flavor of raw bran and fermented bran were evaluated. After treatments, water extractable arabinoxylans were 3-4 times higher than in raw bran. Total dietary fiber and soluble dietary fiber increased after solid state fermentation. Over 20% of phytic acid was degraded. Microstructure changes and protein degradation were observed in fermented brans. Water holding capacity and water retention capacity of fermented brans were improved. Results suggest that solid state fermentation is an effective way to improve the properties of wheat brans. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predicting pear (cv. Clara Frijs) dry matter and soluble solids content with near infrared spectroscopy

DEFF Research Database (Denmark)

Travers, Sylvia; Bertelsen, Marianne; Petersen, Karen

2014-01-01

Regression models for predicting preharvest dry matter (DM) and soluble solids content (SSC), based on two spectral ranges (680-1000 nm and 1100-2350 nm), were compared. Models based on longer NIR spectra were more successful for both parameters (DM/SSC: R2 = 0.78-0.84; RMECV = 0.78/0.44; LVs = 6....../7). SSC prediction was better than expected considering the presence of starch in fruit. Generally poor SSC prediction in the presence of starch could be related to the inability of models to distinguish between forms of carbohydrate. Variable selection and regression coefficients highlighted...... fruit. Further research is needed to qualify and build on the results presented here....

Solid acid catalysts in heterogeneous n-alkanes hydroisomerisation ...

African Journals Online (AJOL)

As the current global environmental concerns have prompted regulations to reduce the level of aromatic compounds, particularly benzene and its derivatives in gasoline, ydroisomerisation of n-alkanes is becoming a major alternative for enhancing octane number. Series of solid acid catalysts comprising of Freidel crafts, ...

Solid Phospholipid Dispersions for Oral Delivery of Poorly Soluble Drugs

DEFF Research Database (Denmark)

Fong, Sophia Yui Kau; Martins, Susana A. M.; Brandl, Martin

2016-01-01

Celecoxib (CXB) is a Biopharmaceutical Classification System class II drug in which its oral bioavailability is limited by poor aqueous solubility. Although a range of formulations aiming to increase the solubility of CXB have been developed, it is not completely understood, whether (1) an increase...... the importance of evaluating both, solubility and permeability, and the use of biorelevant medium for testing the candidate-enabling performance of liposomal formulations. Mechanisms at molecular level that may explain the effect of PL formulations on the permeability of CXB are also discussed....

Structural diversity of solid dispersions of acetylsalicylic acid as seen by solid-state NMR

Czech Academy of Sciences Publication Activity Database

Policianová, Olivia; Brus, Jiří; Hrubý, Martin; Urbanová, Martina; Zhigunov, Alexander; Kredatusová, Jana; Kobera, Libor

2014-01-01

Roč. 11, č. 2 (2014), s. 516-530 ISSN 1543-8384 R&D Projects: GA ČR GPP106/11/P426 Institutional support: RVO:61389013 Keywords : solid dispersions * acetylsalicylic acid * polymers Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 4.384, year: 2014

Predicting the equilibrium solubility of solid polycyclic aromatic hydrocarbons and dibenzothiophene using a combination of MOSCED plus molecular simulation or electronic structure calculations

Science.gov (United States)

Phifer, Jeremy R.; Cox, Courtney E.; da Silva, Larissa Ferreira; Nogueira, Gabriel Gonçalves; Barbosa, Ana Karolyne Pereira; Ley, Ryan T.; Bozada, Samantha M.; O'Loughlin, Elizabeth J.; Paluch, Andrew S.

2017-06-01

Methods to predict the equilibrium solubility of non-electrolyte solids are important for the design of novel separation processes. Here we demonstrate how conventional molecular simulation free energy calculations or electronic structure calculations in a continuum solvent, here SMD or SM8, can be used to predict parameters for the MOdified Separation of Cohesive Energy Density (MOSCED) method. The method is applied to the solutes naphthalene, anthracene, phenanthrene, pyrene and dibenzothiophene, compounds of interested to the petroleum industry and for environmental remediation. Adopting the melting point temperature and enthalpy of fusion of these compounds from experiment, we are able to predict equilibrium solubilities. Comparing to a total of 422 non-aqueous and 193 aqueous experimental solubilities, we find the proposed method is able to well correlate the data. The use of MOSCED is additionally advantageous as it is a solubility parameter-based method useful for intuitive solvent selection and formulation.

Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

Directory of Open Access Journals (Sweden)

Yousaf AM

2016-01-01

Full Text Available Abid Mehmood Yousaf,1,2 Omer Mustapha,1 Dong Wuk Kim,1 Dong Shik Kim,1 Kyeong Soo Kim,1 Sung Giu Jin,1 Chul Soon Yong,3 Yu Seok Youn,4 Yu-Kyoung Oh,5 Jong Oh Kim,3 Han-Gon Choi1 1College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi, South Korea; 2Faculty of Pharmacy, University of Central Punjab, Johar, Lahore, Pakistan; 3College of Pharmacy, Yeungnam University, Gyongsan, North Gyeongsang, 4School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi, 5College of Pharmacy, Seoul National University, Seoul, South Korea Purpose: The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate.Methods: Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion.Results: All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1

In vitro solubility of calcium, iron and zinc in relation to phytic acid levels in rice-based consumer products in China

NARCIS (Netherlands)

Liang, J.; Han, B.Z.; Nout, M.J.R.; Hamer, R.J.

2010-01-01

In vitro solubility of calcium, iron and zinc in relation to phytic acid (PA) levels in 30 commercial rice-based foods from China was studied. Solubility of minerals and molar ratios of PA to minerals varied with degrees of processing. In primary products, [PA]/[Ca] values were less than 5 and

Synthesis and photophysicochemical studies of a water soluble conjugate between folic acid and zinc tetraaminophthalocyanine

Energy Technology Data Exchange (ETDEWEB)

Khoza, Phindile; Antunes, Edith [Department of Chemistry, Rhodes University, PO Box 94, Grahamstown (South Africa); Chen, Ji-Yao [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za [Department of Chemistry, Rhodes University, PO Box 94, Grahamstown (South Africa)

2013-02-15

This work reports on the synthesis of zinc tetraaminophthalocyanine (ZnTAPc) functionalized with folic acid (FA), forming ZnTAPcFA. The conjugate between FA and ZnTAPc was soluble in water whereas ZnTAPc alone is not. The structure of ZnTAPcFA conjugate was elucidated by {sup 1}H NMR, MALDI-TOF mass and FTIR spectra. Photophysical and photochemical studies of ZnTAPcFA were conducted in DMSO. The increase in fluorescence quantum yield of the conjugate was accompanied by a decrease in the triplet and singlet oxygen quantum yields. The changes in triplet quantum and singlet oxygen quantum yields were marginal when ZnTAPc was simply mixed with FA without a chemical bond. - Highlights: Black-Right-Pointing-Pointer A conjugate between folic acid and a zinc tetraaminophthalocyanine was formed. Black-Right-Pointing-Pointer The conjugate is water soluble even though the phthalocyanine alone is not. Black-Right-Pointing-Pointer The fluorescence quantum yield of the conjugate was enhanced compared to the phthalocyanine alone. Black-Right-Pointing-Pointer Triplet quantum yields decreased for the conjugate.

Evaluation of soluble organic compounds generated by radiological degradation of asphalt

International Nuclear Information System (INIS)

Fukumoto, M.; Nishikawa, Y.; Kagawa, A.; Kawamura, K.

2000-12-01

The soluble organic compounds generated by radiological degradation of asphalt (γ ray) were confirmed as a part of influence of the bituminized waste degradation in the TRU waste repository. Especially, the influence of the nitrate was focused on. As a result, the concentration of the soluble organic compounds generated by radiological degradation of asphalt (10 MGy, γ ray which is correspond to absorbed dose of asphalt for 1,000,000 years) were lower (each formic acid: about 50 mg/dm 3 , acetic acid: about 30 mg/dm 3 and oxalic acid: about 2 mg/dm 3 ) than that of the formic acid, the acetic acid and the oxalic acid which Valcke et al. had shown (the influence of the organic at the solubility examination which uses Pu and Am). Moreover, the change in the concentration of TOC and the soluble organic compounds (formic acid, acetic acid and oxalic acid) is little under the existence of nitrate ion. That is, the formic acid and acetic acid which can be organic ligands were generated little by oxidative decomposition of asphalt in the process that nitrate ion becomes nitride ion by radiation. The influence of the soluble organic compounds by the radiological degradation of the asphalt (γ ray) on adsorption and solubility by the complexation of radionuclides in the performance assessment can be limited. (author)

The determination of solubility and diffusion coefficient for solids in liquids by an inverse measurement technique using cylinders of amorphous glucose as a model compound

International Nuclear Information System (INIS)

Hu, Chengyao; Huang, Pei

2011-01-01

The importance of sugar and sugar-containing materials is well recognized nowadays, owing to their application in industrial processes, particularly in the food, pharmaceutical and cosmetic industries. Because of the large numbers of those compounds involved and the relatively small number of solubility and/or diffusion coefficient data for each compound available, it is highly desirable to measure the solubility and/or diffusion coefficient as efficiently as possible and to be able to improve the accuracy of the methods used. In this work, a new technique was developed for the measurement of the diffusion coefficient of a stationary solid solute in a stagnant solvent which simultaneously measures solubility based on an inverse measurement problem algorithm with the real-time dissolved amount profile as a function of time. This study differs from established techniques in both the experimental method and the data analysis. The experimental method was developed in which the dissolved amount of solid solute in quiescent solvent was investigated using a continuous weighing technique. In the data analysis, the hybrid genetic algorithm is used to minimize an objective function containing a calculated and a measured dissolved amount with time. This is measured on a cylindrical sample of amorphous glucose in methanol or ethanol. The calculated dissolved amount, that is a function of the unknown physical properties of the solid solute in the solvent, is calculated by the solution of the two-dimensional nonlinear inverse natural convection problem. The estimated values of the solubility of amorphous glucose in methanol and ethanol at 293 K were respectively 32.1 g/100 g methanol and 1.48 g/100 g ethanol, in agreement with the literature values, and support the validity of the simultaneously measured diffusion coefficient. These results show the efficiency and the stability of the developed technique to simultaneously estimate the solubility and diffusion coefficient. Also

Solubility of neptunium and technetium dioxides in a Yucca Mountain simulated groundwaters

International Nuclear Information System (INIS)

Kulyako, Yu.; Perevalov, S.; Malikov, D.; Myasoedov, B.; Atkins-Duffin, Cynthia E.

2005-01-01

Full text of publication follows: Solubility of NpO 2 and TcO 2 in the Yucca Mountain simulated ground waters J-13 and UE-25p-1 were studied. It is shown that contents of the dissolved neptunium and technetium in simulated groundwater (SGW) depend on solid/liquid phase ratio in these systems under ambient conditions. Average values of NpO 2 solubility in the suspensions of J-13 SGW are equal to (1.1±0.2) x 10 -6 M, (4.7±0.5) x 10 -6 M and (1.3±0.2) x 10 -5 M at solid/liquid ratios (mg/mL) of 0.4, 2.5 and 9.8 respectively. Average solubility values of NpO 2 in the suspensions of UE-25p-1 SGW are equal to (1.6±0.2) x 10 -7 M, (4.3±0.7) x 10 -7 M and (4.2±1.2) x 10 -6 M for solid/liquid ratios (mg/mL) of 1.2, 3.7 and 18.6, respectively. At equal solid/liquid ratios the solubility of NpO 2 in J-13 SGW is higher than that in UE-25p-1 SGW. At equal contents of solid phase in the suspensions solubility of TcO 2 in J-13 SGW are close to those in UE-25p-1 SGW and they are approximately proportional to the solid/liquid ratio. Average values of TcO 2 solubility in the suspensions of J-13 SGW are equal to (3.0±0.2) x 10 -5 M, (1.7±0.2) x 10 -4 , (6.2±0.2) x 10 -4 M at solid/liquid ratios (mg/mL) of 0.6, 4.8 and 15.5 respectively. Average values of TcO 2 solubility in the suspensions of UE-25p-1 SGW are equal to (5.8±0.3) x 10 -5 M, (2.2±0.1) x 10 -4 M and (3.8±0.2) x 10 -4 M at solid/liquid ratios 1.6, 7.0 and 13.6 (mg/mL) respectively. The dependence of solubility of NpO 2 and TcO 2 on solid/liquid ratio may be explained by the fact that transition of the neptunium and technetium from solid phase into the liquid one occurs on phase interface owing to the dissolving of Np(V) and Tc(VII) compounds being formed under ambient conditions. (authors)

[Application of characteristic NIR variables selection in portable detection of soluble solids content of apple by near infrared spectroscopy].

Science.gov (United States)

Fan, Shu-Xiang; Huang, Wen-Qian; Li, Jiang-Bo; Guo, Zhi-Ming; Zhaq, Chun-Jiang

2014-10-01

In order to detect the soluble solids content(SSC)of apple conveniently and rapidly, a ring fiber probe and a portable spectrometer were applied to obtain the spectroscopy of apple. Different wavelength variable selection methods, including unin- formative variable elimination (UVE), competitive adaptive reweighted sampling (CARS) and genetic algorithm (GA) were pro- posed to select effective wavelength variables of the NIR spectroscopy of the SSC in apple based on PLS. The back interval LS- SVM (BiLS-SVM) and GA were used to select effective wavelength variables based on LS-SVM. Selected wavelength variables and full wavelength range were set as input variables of PLS model and LS-SVM model, respectively. The results indicated that PLS model built using GA-CARS on 50 characteristic variables selected from full-spectrum which had 1512 wavelengths achieved the optimal performance. The correlation coefficient (Rp) and root mean square error of prediction (RMSEP) for prediction sets were 0.962, 0.403°Brix respectively for SSC. The proposed method of GA-CARS could effectively simplify the portable detection model of SSC in apple based on near infrared spectroscopy and enhance the predictive precision. The study can provide a reference for the development of portable apple soluble solids content spectrometer.

Towards improved solubility of poorly water-soluble drugs: cryogenic co-grinding of piroxicam with carrier polymers.

Science.gov (United States)

Penkina, Anna; Semjonov, Kristian; Hakola, Maija; Vuorinen, Sirpa; Repo, Timo; Yliruusi, Jouko; Aruväli, Jaan; Kogermann, Karin; Veski, Peep; Heinämäki, Jyrki

2016-01-01

Amorphous solid dispersions (SDs) open up exciting opportunities in formulating poorly water-soluble active pharmaceutical ingredients (APIs). In the present study, novel catalytic pretreated softwood cellulose (CPSC) and polyvinylpyrrolidone (PVP) were investigated as carrier polymers for preparing and stabilizing cryogenic co-ground SDs of poorly water-soluble piroxicam (PRX). CPSC was isolated from pine wood (Pinus sylvestris). Raman and Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used for characterizing the solid-state changes and drug-polymer interactions. High-resolution scanning electron microscope (SEM) was used to analyze the particle size and surface morphology of starting materials and final cryogenic co-ground SDs. In addition, the molecular aspects of drug-polymer interactions and stabilization mechanisms are presented. The results showed that the carrier polymer influenced both the degree of amorphization of PRX and stabilization against crystallization. The cryogenic co-ground SDs prepared from PVP showed an enhanced dissolution rate of PRX, while the corresponding SDs prepared from CPSC exhibited a clear sustained release behavior. In conclusion, cryogenic co-grinding provides a versatile method for preparing amorphous SDs of poorly water-soluble APIs. The solid-state stability and dissolution behavior of such co-ground SDs are to a great extent dependent on the carrier polymer used.

Oral formulation strategies to improve solubility of poorly water-soluble drugs.

Science.gov (United States)

Singh, Abhishek; Worku, Zelalem Ayenew; Van den Mooter, Guy

2011-10-01

In the past two decades, there has been a spiraling increase in the complexity and specificity of drug-receptor targets. It is possible to design drugs for these diverse targets with advances in combinatorial chemistry and high throughput screening. Unfortunately, but not entirely unexpectedly, these advances have been accompanied by an increase in the structural complexity and a decrease in the solubility of the active pharmaceutical ingredient. Therefore, the importance of formulation strategies to improve the solubility of poorly water-soluble drugs is inevitable, thus making it crucial to understand and explore the recent trends. Drug delivery systems (DDS), such as solid dispersions, soluble complexes, self-emulsifying drug delivery systems (SEDDS), nanocrystals and mesoporous inorganic carriers, are discussed briefly in this review, along with examples of marketed products. This article provides the reader with a concise overview of currently relevant formulation strategies and proposes anticipated future trends. Today, the pharmaceutical industry has at its disposal a series of reliable and scalable formulation strategies for poorly soluble drugs. However, due to a lack of understanding of the basic physical chemistry behind these strategies, formulation development is still driven by trial and error.

Cocrystal of Ibuprofen–Nicotinamide: Solid-State Characterization and In Vivo Analgesic Activity Evaluation

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Yori Yuliandra

2018-06-01

Full Text Available Ibuprofen is classified as a BCS class II drug which has low solubility and high permeability. We conducted the formation of the cocrystalline phase of ibuprofen with coformer nicotinamide to increase its solubility. The purpose of this study was to characterize the solid state of cocrystalline phase of ibuprofen-nicotinamide, determine the solubility, and evaluate its in vivo analgesic activity. The cocrystal of ibuprofen-nicotinamide was prepared by a slow evaporation method. The solid-state characterization was conducted by powder X-ray diffraction (PXRD analysis, differential thermal analysis (DTA, and scanning electron microscopy (SEM. To investigate the in vivo analgesic activity, 28 male Swiss-Webster mice were injected with acetic acid 0.5% following oral administration of intact ibuprofen, physical mixture, and its cocrystalline phase with nicotinamide (equivalent to 26 mg/kg ibuprofen. The number of writhes was counted, and pain inhibition was calculated. All data were analyzed with one-way ANOVA followed by Duncan’s Multiple Range Test (95% confidence interval. The results revealed that a new cocrystalline phase was successfully formed. The solubility testing showed that the cocrystal formation enhanced the solubility significantly as compared with the physical mixture and intact ibuprofen. A significant increase in the analgesic activity of cocrystal ibuprofen-nicotinamide was also confirmed.

Equilibrium solubility measurement of ionizable drugs – consensus recommendations for improving data quality

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Alex Avdeef

2016-06-01

Full Text Available This commentary addresses data quality in equilibrium solubility measurement in aqueous solution. Broadly discussed is the “gold standard” shake-flask (SF method used to measure equilibrium solubility of ionizable drug-like molecules as a function of pH. Many factors affecting the quality of the measurement are recognized. Case studies illustrating the analysis of both solution and solid state aspects of solubility measurement are presented. Coverage includes drug aggregation in solution (sub-micellar, micellar, complexation, use of mass spectrometry to assess aggregation in saturated solutions, solid state characterization (salts, polymorphs, cocrystals, polymorph creation by potentiometric method, solubility type (water, buffer, intrinsic, temperature, ionic strength, pH measurement, buffer issues, critical knowledge of the pKa, equilibration time (stirring and sedimentation, separating solid from saturated solution, solution handling and adsorption to untreated surfaces, solubility units, and tabulation/graphic presentation of reported data. The goal is to present cohesive recommendations that could lead to better assay design, to result in improved quality of measurements, and to impart a deeper understanding of the underlying solution chemistry in suspensions of drug solids.

Determination of solubility isotherms of barium and strontium nitrates in the system acetic acid-water at 25/sup 0/ C

Energy Technology Data Exchange (ETDEWEB)

Hubicki, W.; Piskorek, M. (Uniwersytet Marii Curie-Sklodowskiej, Lublin (Poland))

1976-01-01

Investigations of the solubility of barium and strontium nitrates were carried out in the system: acetic acid - water at 25/sup 0/ C. When one compares the isotherms of solubility of barium and strontium nitrates, one can observe that it is possible to separate the admixtures of barium from strontium nitrates as a result of fractional crystallization of these nitrates from actic acid solution at the temperatures lower than 31.3/sup 0/ C, i.e. below the temperature of transformation: Sr(NO/sub 3/)/sub 2/ . 4H/sub 2/O reversible to Sr(NO/sub 3/)/sub 2/ + 4H/sub 2/O for aqueous solution.

Synthesis of LiBOB Fine Powder to Increase Solubility

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Etty Marti Wigayati

2017-04-01

Full Text Available Lithium bis (oxalate borate or LiBOB compound has captured interest of researchers, because it is potentially viable to be used as electrolyte salt in lithium-ion battery system. This compound is easy to synthesize and considered to be more environmentally friendly compared to conventional electrolyte salt because LiBOB does not contain halogen element. This research focused on the synthesis of LiBOB fine powder, which main purpose is improving LiBOB salt solubility in liquid electrolyte solution. This will aid the ion transfer between electrodes which in turn will increase the electrolyte performance. Solid state reaction was employed in this experiment. Synthesis of LiBOB compound was performed by reacting oxalic acid dihydrate, lithium hydroxide monohydrate, and boric acid. The resulting powder was then processed into fine powder using ball milling technique with varying milling time (0, 6, 10, and 13 hour. Microstructure of the sample was then analyzed to obtain information regarding phase formation, functional groups, grain surface morphology, surface area, pore volume, solubility, and ionic conductivity. The analysis shown that LiBOB and LiBOB hydrate phase was formed during the reaction, there was no changed in existing phase during milling process, crystallinity index was shifted to lower value but there was no difference in functional groups. Highest value in surface area was found to be 83.11 m2/g, with pore volume of 1.21311e+02 A at 10 hours milling. Smaller powder size resulted in higher solubility, unfortunately the ionic conductivity was found to be decreased.

Soluble and cell wall-bound phenolic acids and ferulic acid dehydrodimers in rye flour and five bread model systems: insight into mechanisms of improved availability.

Science.gov (United States)

Dynkowska, Wioletta M; Cyran, Malgorzata R; Ceglińska, Alicja

2015-03-30

The bread-making process influences bread components, including phenolics that significantly contribute to its antioxidant properties. Five bread model systems made from different rye cultivars were investigated to compare their impact on concentration of ethanol-soluble (free and ester-bound) and insoluble phenolics. Breads produced by a straight dough method without acid addition (A) and three-stage sourdough method with 12 h native starter preparation (C) exhibited the highest, genotype-dependent concentrations of free phenolic acids. Dough acidification by direct acid addition (method B) or by gradual production during prolonged starter fermentation (24 and 48 h, for methods D and E) considerably decreased their level. However, breads B were enriched in soluble ester-bound fraction. Both direct methods, despite substantial differences in dough pH, caused a similar increase in the amount of insoluble ester-bound fraction. The contents of phenolic fractions in rye bread were positively related to activity level of feruloyl esterase and negatively to those of arabinoxylan-hydrolysing enzymes in wholemeal flour. The solubility of rye bread phenolics may be enhanced by application of a suitable bread-making procedure with respect to rye cultivar, as the mechanisms of this process are also governed by a response of an individual genotype with specific biochemical profile. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Science.gov (United States)

Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

2018-04-01

While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Directory of Open Access Journals (Sweden)

B. Jing

2018-04-01

Full Text Available While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO32 and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA. The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase[S

Science.gov (United States)

Oguro, Ami; Imaoka, Susumu

2012-01-01

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hydrolyzed products. Although lecithin itself did not inhibit the phosphatase activity, the hydrolyzed lecithin significantly inhibited it, suggesting that lysophospholipid or fatty acid can inhibit it. Next, we investigated the inhibition of phosphatase activity by lysophosphatidyl choline, palmitoyl lysophosphatidic acid, monopalmitoyl glycerol, and palmitic acid. Palmitoyl lysophosphatidic acid and fatty acid efficiently inhibited phosphatase activity, suggesting that lysophosphatidic acids (LPAs) are substrates for the phosphatase activity of sEH. As expected, palmitoyl, stearoyl, oleoyl, and arachidonoyl LPAs were efficiently dephosphorylated by sEH (Km, 3–7 μM; Vmax, 150–193 nmol/min/mg). These results suggest that LPAs are substrates of sEH, which may regulate physiological functions of cells via their metabolism. PMID:22217705

Acetanilide interaction with hydriodic acid in aqueous solutions at 20 and 40 deg C

International Nuclear Information System (INIS)

Erkasov, R.Sh.; Nurakhmetov, N.I.

1990-01-01

Isothermal method was used to study acetanilide solubility in aqueous solutions of hydriodic acid at 20 and 40 deg C. formation of two new anhydrous compounds of 2:1 and 1:1 compositions (anilide: acid molar ratio) was established. Temperature and concentration boundaries of solid phase formation were established for these compounds. Their IR spectroscopic investigation was conducted

Solvent-Free Polymerization of L-Aspartic Acid in the Presence of D-Sorbitol to Obtain Water Soluble or Network Copolymers

Science.gov (United States)

L-aspartic acid was thermally polymerized in the presence of D-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 degrees C. In contrast, heating sorbitol and aspartic ac...

Solid dispersion application in pharmaceutical technology: Methods of preparation and characterization

OpenAIRE

Medarević, Đorđe; Ibrić, Svetlana; Đuriš, Jelena; Đurić, Zorica

2013-01-01

A growing number of newly synthesized drugs exhibit low aqueous solubility, leading to poor bioavailability. Therefore, improving drug solubility and dissolution rate became one of the greatest challenges during formulation development. Solid dispersions formulation is one of the commonly investigated techniques for improving solubility of poorly soluble drugs. Solid dispersions are dispersions of one or more drugs in an inert carrier (matrix) in the solid state prepared by melting, solvent, ...

A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid

International Nuclear Information System (INIS)

Meral, Kadem; Erbil, H. Yıldırım; Onganer, Yavuz

2011-01-01

Mono and multilayer of water-soluble pyronin B (PyB) and pyronin Y (PyY) mixed with stearic acid (SA) have been incorporated in Langmuir-Blodgett (LB) films. The surface pressure-area (π-A) isotherm studies pointed out that pure PyB and PyY are incapable of forming stable films at air-water interface and collapsed readily at low surface pressures. However, mixture of PyB or PyY with SA easily formed stable films at the air-water interface and they were easily transferred onto solid substrates. The average area per molecule of mixed films of PyB and PyY at the air-water interface was observed to decrease with increasing concentrations of PyB and PyY. The spectroscopic characteristics of PyB and PyY in chloroform, in SA containing chloroform and in LB films have also been investigated by using absorption and steady-state and time-resolved fluorescence spectroscopy techniques. The morphology of the LB film surfaces has been characterized by using atomic force microscopy (AFM).

A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid

Energy Technology Data Exchange (ETDEWEB)

Meral, Kadem [Department of Chemistry, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey); Erbil, H. Y Latin-Small-Letter-Dotless-I ld Latin-Small-Letter-Dotless-I r Latin-Small-Letter-Dotless-I m [Department of Chemical Engineering, Gebze Institute of Technology, Cay Latin-Small-Letter-Dotless-I rova, Gebze 41400, Kocaeli (Turkey); Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr [Department of Chemistry, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey)

2011-12-01

Mono and multilayer of water-soluble pyronin B (PyB) and pyronin Y (PyY) mixed with stearic acid (SA) have been incorporated in Langmuir-Blodgett (LB) films. The surface pressure-area ({pi}-A) isotherm studies pointed out that pure PyB and PyY are incapable of forming stable films at air-water interface and collapsed readily at low surface pressures. However, mixture of PyB or PyY with SA easily formed stable films at the air-water interface and they were easily transferred onto solid substrates. The average area per molecule of mixed films of PyB and PyY at the air-water interface was observed to decrease with increasing concentrations of PyB and PyY. The spectroscopic characteristics of PyB and PyY in chloroform, in SA containing chloroform and in LB films have also been investigated by using absorption and steady-state and time-resolved fluorescence spectroscopy techniques. The morphology of the LB film surfaces has been characterized by using atomic force microscopy (AFM).

Acidity of cations and the solubility of oxides in the eutectic KCl-LiCl melt at 700 Deg C

International Nuclear Information System (INIS)

Cherginets, V.L.; Rebrova, T.P.

1999-01-01

Products of MgO, NiO and CoO solubility in KCl-LiCl melt at 700 Deg C were determined by the method of potentiometric titration using Pt(O 2 )IZrO 2 (Y 2 O 3 ) membrane oxygen electrode. It was ascertained that acid properties of Cd 2+ and Pb'2 + cations are levelled to Li + properties, a break in E-pO graduation dependence in KCl-LiCl melt was observed at pO ∼ 2. Increase in oxides solubility in the melt studied compared with KCl-NaCl and CsCl-KCl-NaCl melts stems from the presence of Li + cations in the melt studied, which possess stronger acid properties than those of Na + or K + [ru

Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium Azospirillum spp.

Science.gov (United States)

Rodriguez, Hilda; Gonzalez, Tania; Goire, Isabel; Bashan, Yoav

2004-11-01

In vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria A. brasilense (Cd and 8-I) and one strain of A. lipoferum JA4 were studied. Strains of A. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. At the same time, there is a reduction in pH of the medium and release of soluble phosphate. To a greater extent, gluconic acid production and pH reduction were observed for A. lipoferum JA4. For the three strains, clearing halos were detected on solid medium plates with calcium phosphate. This is the first report of in vitro gluconic acid production and direct phosphate solubilization by A. brasilense and the first report of P solubilization by A. lipoferum. This adds to the very broad spectrum of plant growth-promoting abilities of this genus.

Effect of Postharvest Oxalic Acid and Calcium Chloride on Quality Attributes of Sweet Cherry (Prunus avium L.

Directory of Open Access Journals (Sweden)

M. Safa

2016-02-01

Full Text Available Introduction: Fruits and vegetables have special importance as a very important part of the human food supply. And from the beginnings of life, man has used these products to supply a part of his food. Nowadays, horticultural products are widely used in the diet. Cherry is one of the deciduous trees in the temperate regions, which is potassium rich. Use of Oxalic acid significantly reduces frost injury in pomegranate fruits during storage at a temperature of 2° C. In fruit trees, the importance of calcium is due to a delay in fruit ripening process and this way products have better portability. Materials and Methods: Firmness test was measured using the FT011 model of penetrometer. For determination of titratable acidity, the 0.1 N sodium hydroxide (NaOH titration method was used. Total Soluble solids content (SSC of fruit was measured by a digital refractometer (PAL-1. For determination of vitamin C in fruit juices, titration method with the indicator, 2,6-di-chlorophenolindophenol was used. Fruit juice pH was measured using pH meter model HI 9811.In order to investigate the effect of postharvest soaking treatment with Oxalic acid on the qualitative specifications and storage life of single grain sweet cherry fruit a research was conducted. This experience was conducted in a completely randomized design with 3 replications separately for the two materials. In this experiment Oxalic acid, in four levels (0,4,6 and 8 mM and Calcium chloride in four levels (0, 40, 55 and 70 mM were applied on the single grain sweet cherry fruit in the form of soaking and sampleswith7-day intervals for a period of 28 days from the fridge out and quanti tate and qualitative traits such as stiffness, weight loss, Titratable acidity, total soluble solids, vitamin C and pH were measured. Results and Discussion: The results showed that compared with control ones all of the concentrations of Oxalic acid and Calcium chloride caused significant differences in the amount

Andrographolide: solving chemical instability and poor solubility by means of cocrystals.

Science.gov (United States)

Suresh, Kuthuru; Goud, N Rajesh; Nangia, Ashwini

2013-12-01

The bioactive agent andrographolide was screened with pharmaceutically acceptable coformers to discover a novel solid form that will solve the chemical instability and poor solubility problems of this herbal medicine. Liquid-assisted grinding of andrographolide with GRAS (generally regarded as safe) coformers in a fixed stoichiometry resulted in cocrystals with vanillin (1:1), vanillic acid (1:1), salicylic acid (1:1), resorcinol (1:1), and guaiacol (1:1). All the crystalline products were characterized by thermal, spectroscopic, and diffraction methods. Interestingly, even though the cocrystals are isostructural, their physicochemical properties are quite different. The andrographolide-salicylic acid cocrystal completely inhibited the chemical transformation of andrographolide to its inactive sulfate metabolite, and moreover, the cocrystal exhibited a dissolution rate that was three times faster and a drug release that was two times higher than pure andrographolide. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

IMPROVEMENT OF SOLUBILITY OF BADLY WATER SOLUBLE DRUG (IBUPROFEN) BY USING SURFACTANTS AND CARRIERS

OpenAIRE

Md. Zakaria Faruki*, Rishikesh, Elizabeth Razzaque, Mohiuddin Ahmed Bhuiyan

2013-01-01

ABSTRACT: Although there was a great interest in solid dispersion systems during the past four decades to increase dissolution rate and bioavailability of badly water-soluble drugs, their profitable use has been very limited, primarily because of manufacturing difficulties and stability problems. In this study solid solutions of drugs were generally produced by fusion method. The drug along with the excipients (surfactants and carriers) was heated first and then hardened by cooling to room te...

Nitric acid adduct formation during crystallization of barium and strontium nitrates and their co-precipitation from nitric acid media

International Nuclear Information System (INIS)

Mishina, N.E.; Zilberman, B.Ya.; Lumpov, A.A.; Koltsova, T.I.; Puzikov, E.A.; Ryabkov, D.V.

2015-01-01

The molar solubilities of Ba, Sr and Pb nitrates in nitric acid as a function of total nitrate concentration is presented and described by the mass action law, indicating on formation of the adducts with nitric acid. Precipitates of Ba(NO 3 ) 2 and Sr(NO 3 ) 2 crystallized from nitric acid were studied by ISP OES and IR spectroscopy. The data obtained confirmed formation of metastable adducts with nitric acid. IR and X-ray diffraction studies of the mixed salt systems indicated conversion of the mixed salts into (Ba,Sr)(NO 3 ) 2 solid solution of discrete structure in range of total nitrate ion concentration ∼6 mol/L. (author)

Effect of initial total solids concentration on volatile fatty acid production from food waste during anaerobic acidification.

Science.gov (United States)

Wang, Quan; Jiang, Jianguo; Zhang, Yujing; Li, Kaimin

2015-01-01

The effect of initial total solids (TS) concentration on volatile fatty acid (VFAs) production from food waste under mesophilic conditions (35 °C) was determined. VFAs concentration and composition, biogas production, soluble chemical oxygen demand concentration, TS and volatile solids (VS) reduction, and ammonia nitrogen [Formula: see text] release were investigated. The VFAs concentrations were 26.10, 39.68, 59.58, and 62.64 g COD/L at TS contents of 40, 70, 100, and 130 g/L, respectively. While the VFAs' yields ranged from 0.467 to 0.799 g COD/g VSfed, decreased as initial TS increased. The percentage of propionate was not affected by TS concentration, accounting for 30.19-34.86% of the total VFAs, while a higher percentage of butyrate and lower percentage of acetate was achieved at a higher TS concentration. Biogas included mainly hydrogen and carbon dioxide and the maximum hydrogen yield of 148.9 ml/g VSfed was obtained at 130 g TS/L. [Formula: see text] concentration, TS and VS reductions increased as initial TS increased. Considering the above variables, we conclude that initial TS of 100 g/L shall be the most appropriate to VFAs production.

Coamorphous Loratadine-Citric Acid System with Enhanced Physical Stability and Bioavailability.

Science.gov (United States)

Wang, Jin; Chang, Ruimiao; Zhao, Yanan; Zhang, Jiye; Zhang, Ting; Fu, Qiang; Chang, Chun; Zeng, Aiguo

2017-10-01

Coamorphous systems using citric acid as a small molecular excipient were studied for improving physical stability and bioavailability of loratadine, a BCS class II drug with low water solubility and high permeability. Coamorphous loratadine-citric acid systems were prepared by solvent evaporation technique and characterized by differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Solid-state analysis proofed that coamorphous loratadine-citric acid system (1:1) was amorphous and homogeneous, had a higher T g over amorphous loratadine, and the intermolecular hydrogen bond interactions between loratadine and citric acid exist. The solubility and dissolution of coamorphous loratadine-citric acid system (1:1) were found to be significantly greater than those of crystalline and amorphous form. The pharmacokinetic study in rats proved that coamorphous loratadine-citric acid system (1:1) could significantly improve absorption and bioavailability of loratadine. Coamorphous loratadine-citric acid system (1:1) showed excellently physical stability over a period of 3 months at 25°C under 0% RH and 25°C under 60% RH conditions. The improved stability of coamorphous loratadine-citric acid system (1:1) could be related to an elevated T g over amorphous form and the intermolecular hydrogen bond interactions between loratadine and citric acid. These studies demonstrate that the developed coamorphous loratadine-citric acid system might be a promising oral formulation for improving solubility and bioavailability of loratadine.

Head-To-Head Comparison of Different Solubility-Enabling Formulations of Etoposide and Their Consequent Solubility-Permeability Interplay.

Science.gov (United States)

Beig, Avital; Miller, Jonathan M; Lindley, David; Carr, Robert A; Zocharski, Philip; Agbaria, Riad; Dahan, Arik

2015-09-01

The purpose of this study was to conduct a head-to-head comparison of different solubility-enabling formulations, and their consequent solubility-permeability interplay. The low-solubility anticancer drug etoposide was formulated in several strengths of four solubility-enabling formulations: hydroxypropyl-β-cyclodextrin, the cosolvent polyethylene glycol 400 (PEG-400), the surfactant sodium lauryl sulfate, and an amorphous solid dispersion formulation. The ability of these formulations to increase the solubility of etoposide was investigated, followed by permeability studies using the parallel artificial membrane permeability assay (PAMPA) and examination of the consequent solubility-permeability interplay. All formulations significantly increased etoposide's apparent solubility. The cyclodextrin-, surfactant-, and cosolvent-based formulations resulted in a concomitant decreased permeability that could be modeled directly from the proportional increase in the apparent solubility. On the contrary, etoposide permeability remained constant when using the ASD formulation, irrespective of the increased apparent solubility provided by the formulation. In conclusion, supersaturation resulting from the amorphous form overcomes the solubility-permeability tradeoff associated with other formulation techniques. Accounting for the solubility-permeability interplay may allow to develop better solubility-enabling formulations, thereby maximizing the overall absorption of lipophilic orally administered drugs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

In vitro oxidation of indoleacetic acid by soluble auxin-oxidases and peroxidases from maize roots

International Nuclear Information System (INIS)

Beffa, R.; Martin, H.V.; Pilet, P.E.

1990-01-01

Soluble auxin-oxidases were extracted from Zea mays L. cv LG11 apical root segments and partially separated from peroxidases (EC 1.11.1.7) by size-exclusion chromatography. Auxin-oxidases were resolved into one main peak corresponding to a molecular mass of 32.5 kilodaltons and a minor peak at 54.5 kilodaltons. Peroxidases were separated into at least four peaks, with molecular masses from 32.5 to 78 kilodaltons. In vitro activity of indoleacetic acid-oxidases was dependent on the presence of MnCl 2 and p-coumaric acid. Compound(s) present in the crude extract and several synthetic auxin transport inhibitors (including 2,3,5-triiodobenzoic acid and N-1-naphthylphthalamic acid) inhibited auxin-oxidase activity, but had no effect on peroxidases. The products resulting from the in vitro enzymatic oxidation of [ 3 H]indoleacetic acid were separated by HPLC and the major metabolite was found to cochromatograph with indol-3yl-methanol

First evidence of a water-soluble plutonium(IV) hexanuclear cluster

Energy Technology Data Exchange (ETDEWEB)

Tamain, Christelle; Dumas, Thomas; Guillaumont, Dominique; Guilbaud, Philippe [CEA, Nuclear Energy Division, Marcoule, RadioChemistry and Processes Department, Bagnols sur Ceze (France); Hennig, Christoph [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Dresden (Germany)

2016-08-15

The singular Pu{sup IV} hexanuclear cluster [Pu{sub 6}(OH){sub 4}O{sub 4}]{sup 12+} stabilized by 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) ligands was structurally characterized for the first time both in the solid state and in water solution by using X-ray diffraction and X-ray absorption and UV/Vis spectroscopy. The stability of this cluster in water and its high solubility over a large pH range are of upmost importance for plutonium environmental speciation with potential applications in a related migration model. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Molecular Thermodynamic Modeling of Mixed Solvent Solubility

DEFF Research Database (Denmark)

Ellegaard, Martin Dela; Abildskov, Jens; O’Connell, John P.

2010-01-01

A method based on statistical mechanical fluctuation solution theory for composition derivatives of activity coefficients is employed for estimating dilute solubilities of 11 solid pharmaceutical solutes in nearly 70 mixed aqueous and nonaqueous solvent systems. The solvent mixtures range from...... nearly ideal to strongly nonideal. The database covers a temperature range from 293 to 323 K. Comparisons with available data and other existing solubility methods show that the method successfully describes a variety of observed mixed solvent solubility behaviors using solute−solvent parameters from...

Quantifying solubility enhancement due to particle size reduction and crystal habit modification: case study of acetyl salicylic acid.

Science.gov (United States)

Hammond, Robert B; Pencheva, Klimentina; Roberts, Kevin J; Auffret, Tony

2007-08-01

The poor solubility of potential drug molecules is a significant problem in the design of pharmaceutical formulations. It is well known, however, that the solubility of crystalline materials is enhanced when the particle size is reduced to submicron levels and this factor can be expected to enhance drug product bioavailability. Direct estimation of solubility enhancement, as calculated via the Gibbs-Thompson relationship, demands reasonably accurate values for the particle/solution interfacial tension and, in particular, its anisotropy with respect to the crystal product's habit and morphology. In this article, an improved, more molecule-centered, approach is presented towards the calculation of solubility enhancement factors in which molecular modeling techniques are applied, and the effects associated with both crystal habit modification and solvent choice are examined. A case study for facetted, acetyl salicylic acid (aspirin) crystals in equilibrium with saturated aqueous ethanol solution reveals that their solubility will be enhanced in the range (7-58%) for a crystal size of 0.02 microm, with significantly higher enhancement for crystal morphologies in which the hydrophobic crystal faces are more predominant than the hydrophilic faces and for solvents in which the solubility is smaller. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

Study of solubility of some metal cyclohexane carbonates

International Nuclear Information System (INIS)

Niyazov, A.N.; Amanov, K.B.; Trapeznikova, V.F.; Kul'maksimov, A.; Kolosova, N.

1978-01-01

The solubility of calcium, magnesium, strontium, barium, cabalt, copper and aluminium cyclohexane, carbonates (CHC) in water has been studied at 25 deg C. The salt solubility has been calculated according to the metal ion concentration in saturated solutions. It has been established, that the cobalt and rare earth cyclohexane carbonates are relatively very soluble in water and have solubility products of SP > 1x10 -5 . The solubility of CHC of multivalent metals increases with the decrease of pH values. Each salt has some ''limiting'' pH value of a solution, below which it decomposes completely and can not exist in a solution in the form of solid phase

Solid-state NMR studies of nucleic acid components

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Hodgkinson, P.

2015-01-01

Roč. 5, č. 16 (2015), s. 12300-12310 ISSN 2046-2069 R&D Projects: GA ČR GA13-24880S Institutional support: RVO:61388963 Keywords : NMR spectroscopy * nucleic acid s * solid-state NMR Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.289, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/ra/c4ra14404j

The potential of Pleurotus-treated olive mill solid waste as cattle feed.

Science.gov (United States)

Shabtay, Ariel; Hadar, Yitzhak; Eitam, Harel; Brosh, Arieh; Orlov, Alla; Tadmor, Yaakov; Izhaki, Ido; Kerem, Zohar

2009-12-01

The aims of the current study were to follow: (1) the capability of the edible mushroom Pleurotus ostreatus to degrade cell wall components and soluble phenols of the olive mill solid waste (OMSW), and improve it for ruminant nutrition (2) the fate of oil and the lipid-soluble compounds tocopherols, squalene and beta-sitosterol in the fermented OMSW. A significant decrease in oil and lipid-soluble compounds with a concomitant shift in the fatty acid profile and degradation of soluble phenols took place already after 14 d. The utilization of lipids by the fungus shifted the degradation of the structural carbohydrates to a later stage, and significantly reduced the metabolizable energy of the OMSW. We propose that edible fungi with reduced lipase activity would preserve the energy and health promoting ingredients of the oil, and force the fungus to degrade structural carbohydrates, thus improving its digestibility.

Consequences of acid strength for isomerization and elimination catalysis on solid acids.

Science.gov (United States)

Macht, Josef; Carr, Robert T; Iglesia, Enrique

2009-05-13

We address here the manner in which acid catalysis senses the strength of solid acids. Acid strengths for Keggin polyoxometalate (POM) clusters and zeolites, chosen because of their accurately known structures, are described rigorously by their deprotonation energies (DPE). Mechanistic interpretations of the measured dynamics of alkane isomerization and alkanol dehydration are used to obtain rate and equilibrium constants and energies for intermediates and transition states and to relate them to acid strength. n-Hexane isomerization rates were limited by isomerization of alkoxide intermediates on bifunctional metal-acid mixtures designed to maintain alkane-alkene equilibrium. Isomerization rate constants were normalized by the number of accessible protons, measured by titration with 2,6-di-tert-butylpyridine during catalysis. Equilibrium constants for alkoxides formed by protonation of n-hexene increased slightly with deprotonation energies (DPE), while isomerization rate constants decreased and activation barriers increased with increasing DPE, as also shown for alkanol dehydration reactions. These trends are consistent with thermochemical analyses of the transition states involved in isomerization and elimination steps. For all reactions, barriers increased by less than the concomitant increase in DPE upon changes in composition, because electrostatic stabilization of ion-pairs at the relevant transition states becomes more effective for weaker acids, as a result of their higher charge density at the anionic conjugate base. Alkoxide isomerization barriers were more sensitive to DPE than for elimination from H-bonded alkanols, the step that limits 2-butanol and 1-butanol dehydration rates; the latter two reactions showed similar DPE sensitivities, despite significant differences in their rates and activation barriers, indicating that slower reactions are not necessarily more sensitive to acid strength, but instead reflect the involvement of more unstable organic

Mechanistic study of solubility enhancement of nifedipine using vitamin E TPGS or solutol HS-15.

Science.gov (United States)

Rajebahadur, Minal; Zia, Hossein; Nues, Anthony; Lee, Chong

2006-01-01

The objective of our study was to find mechanisms responsible for solubility enhancement of nifedipine in solid dispersions of vitamin E TPGS and/or solutol HS-15. Solid dispersions of nifedipine with selected polymers such as vitamin E TPGS, solutol HS-15, PEG(1,000), and lipocol C-10 of varying drug/polymer ratios were prepared by a fusion method. The solubility enhancement was found to be in the order of vitamin E TPGS > solutol HS-15 > lipocol C-10 > PEG(1,000). Lipocol C-10, with a similar hydrophilic-lipophilic value as vitamin E TPGS, showed a comparable retained solubility enhancement during saturation solubility studies but had lower dissolution profile. Overall, vitamin E TPGS showed the best solubility and dissolution performance, while solutol HS-15 and lipocol C-10 demonstrated moderate solubility enhancements. Solid dispersions of vitamin E TPGS as prepared by microfluidization technique initially showed slightly higher solubility compared with samples prepared by fusion method, but eventually it became the same as the study progressed. However, solid dispersion of solutol HS-15 as prepared by microfluidization demonstrated a significant, sustained increased in solubility over its sample when prepared by fusion method. Based on these results, we concluded that enhanced solubility using vitamin E TPGS and solutol HS-15 resulted from a partial conversion of crystalline drug to the amorphous form, increase in wettability of the drug by water soluble polymers, better separation of drug particles, micellar solubilization of drug by high concentrations of surfactant polymers, and interaction between polymer and drug at the molecular level.

Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase[S

OpenAIRE

Oguro, Ami; Imaoka, Susumu

2012-01-01

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hyd...

Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

Directory of Open Access Journals (Sweden)

Ali Ahmed Mahmoud Abdelhaleem

2015-06-01

Full Text Available This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ and various carboxylic acid plasticizers (CAPs. The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2 showed the highest dissolution percentage (> 95 % in 20 minutes compared to pure crystalline CZ (56 %. Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

A water-soluble, mucoadhesive quaternary ammonium chitosan-methyl-β-cyclodextrin conjugate forming inclusion complexes with dexamethasone.

Science.gov (United States)

Piras, Anna Maria; Zambito, Ylenia; Burgalassi, Susi; Monti, Daniela; Tampucci, Silvia; Terreni, Eleonora; Fabiano, Angela; Balzano, Federica; Uccello-Barretta, Gloria; Chetoni, Patrizia

2018-03-30

The ocular bioavailability of lipophilic drugs, such as dexamethasone, depends on both drug water solubility and mucoadhesion/permeation. Cyclodextrins and chitosan are frequently employed to either improve drug solubility or prolong drug contact onto mucosae, respectively. Although the covalent conjugation of cyclodextrin and chitosan brings to mucoadhesive drug complexes, their water solubility is restricted to acidic pHs. This paper describes a straightforward grafting of methyl-β-cyclodextrin (MCD) on quaternary ammonium chitosan (QA-Ch60), mediated by hexamethylene diisocyanate. The resulting product is a water-soluble chitosan derivative, having a 10-atom long spacer between the quaternized chitosan and the cyclodextrin. The derivative is capable of complexing the model drug dexamethasone and stable complexes were also observed for the lyophilized products. Furthermore, the conjugate preserves the mucoadhesive properties typical of quaternized chitosan and its safety as solubilizing excipient for ophthalmic applications was preliminary assessed by in vitro cytotoxicity evaluations. Taken as a whole, the observed features appear promising for future processing of the developed product into 3D solid forms, such as controlled drug delivery systems, films or drug eluting medical devices.

Synthesis of acid-soluble spore proteins by Bacillus subtilis.

Science.gov (United States)

Leventhal, J M; Chambliss, G H

1982-12-01

The major acid-soluble spore proteins (ASSPs) of Bacillus subtilis were detected by immunoprecipitation of radioactively labeled in vitro- and in vivo-synthesized proteins. ASSP synthesis in vivo began 2 h after the initiation of sporulation (t2) and reached its maximum rate at t7. This corresponded to the time of synthesis of mRNA that stimulated the maximum rate of ASSP synthesis in vitro. Under the set of conditions used in these experiments, protease synthesis began near t0, alkaline phosphatase synthesis began at about t2, and refractile spores were first observed between t7 and t8. In vivo- and in vitro-synthesized ASSPs comigrated in sodium dodecyl sulfate-polyacrylamide gels. Their molecular weights were 4,600 (alpha and beta) and 11,000 (gamma). The average half-life of the ASSP messages was 11 min when either rifampin (10 micrograms/ml) or actinomycin D (1 microgram/ml) was used to inhibit RNA synthesis.

Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

International Nuclear Information System (INIS)

Jiang, Tingshun; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

2014-01-01

Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH 3 -TPD and N 2 physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO 4 2− /Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h −1 and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO 4 2− /Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO 4 2− /Zr-MCM-48-25

Investigation of heterogeneous solid acid catalyst performance on low grade feedstocks for biodiesel production: A review

International Nuclear Information System (INIS)

Mansir, Nasar; Taufiq-Yap, Yun Hin; Rashid, Umer; Lokman, Ibrahim M.

2017-01-01

Highlights: • Solid acid catalysts are proficient to esterifying high free fatty acid feedstocks to biodiesel. • Heterogeneous catalysts have the advantage of easy separation and reusability. • Heterogeneous basic catalysts have limitations due to high FFA of low cost feedstocks. • Solid catalysts having acid and base sites reveal better catalyst for biodiesel production. - Abstract: The conventional fossil fuel reserves are continually declining worldwide and therefore posing greater challenges to the future of the energy sources. Biofuel alternatives were found promising to replace the diminishing fossil fuels. However, conversion of edible vegetable oils to biodiesel using homogeneous acids and base catalysts is now considered as indefensible for the future particularly due to food versus fuel competition and other environmental problems related to catalyst system and feedstock. This review has discussed the progression in research and growth related to heterogeneous catalysts used for biodiesel production for low grade feedstocks. The heterogeneous base catalysts have revealed effective way to produce biodiesel, but it has the limitation of being sensitive to high free fatty acid (FFA) or low grade feedstocks. Alternatively, solid acid catalysts are capable of converting the low grade feedstocks to biodiesel in the presence of active acid sites. The paper presents a comprehensive review towards the investigation of solid acid catalyst performance on low grade feedstock, their category, properties, advantages, limitations and possible remedy to their drawbacks for biodiesel production.

Calculation of solubility of salts in binary aqueous solutions

International Nuclear Information System (INIS)

Kolker, A.R.

1990-01-01

The possibility of theoretical calculation of solubility of some salts of the MX-type, where M - Na, K, Cs; X - F-I, as well as CsNO 3 and others forming no crystal hydrates in the solid phase, and the azeotropic composition in the water-HNO 3 system is studied. The calculational results of solubility are shown to depend very much on the values accepted for the standard free energies of component formation, melting heats and crystallization and on the difference in heat capacity of the melt and the solid phase

Hydrogen solubility in polycrystalline - and nonocrystalline niobium

International Nuclear Information System (INIS)

Ishikawa, T.T.; Silva, J.R.G. da

1981-01-01

Hydrogen solubility in polycrystalline and monocrystalline niobium was measured in the range 400 0 C to 1000 0 C at one atmosphere hydrogen partial pressure. The experimental technique consists of saturation of the solvent metal with hydrogen, followed by quenching and analysis of the solid solution. It is presented solubility curves versus reciprocal of the absolute doping temperature, associated with their thermodynamical equation. (Author) [pt

Crystalline Ethylene Oxide and Propylene Oxide Triblock Copolymer Solid Dispersion Enhance Solubility, Stability and Promoting Time- Controllable Release of Curcumin.

Science.gov (United States)

Alves, Thais F R; das Neves Lopes, Franciely C C; Rebelo, Marcia A; Souza, Juliana F; da Silva Pontes, Katiusca; Santos, Carolina; Severino, Patricia; Junior, Jose M O; Komatsu, Daniel; Chaud, Marco V

2018-01-01

The design and development of an effective medicine are, however, often faced with a number of challenges. One of them is the close relationship of drug's bioavailability with solubility, dissolution rate and permeability. The use of curcumin's (CUR) therapeutic potential is limited by its poor water solubility and low chemical stability. The purpose was to evaluate the effect of polymer and solid dispersion (SD) preparation techniques to enhance the aqueous solubility, dissolution rate and stability of the CUR. The recent patents on curcumin SD were reported as (i) curcumin with polyvinylpyrrolidone (CN20071 32500 20071214, WO2006022012 and CN20151414227 20150715), (ii) curcumin-zinc/polyvinylpyrrolidone (CN20151414227 20150715), (iii) curcumin-poloxamer 188 (CN2008171177 20080605), (iv) curcumin SD prepared by melting method (CN20161626746-20160801). SD obtained by co-preciptation or microwave fusion and the physical mixture of CUR with Poloxamer-407 (P-407), Hydroxypropylmetylcellulose-K4M (HPMC K4M) and Polyvinylpyrrolidone-K30 (PVP-K30) were prepared at the ratios of 1:2; 1:1 and 2:1. The samples were evaluated by solubility, stability, dissolution rate and characterized by SEM, PXRD, DSC and FTIR. The solubility, stability (pH 7.0) and dissolution rate were significantly greater for SD (CUR:P-407 1:2). The PXRD,SEM and DSC indicated a change in the crystalline state of CUR. The enhancement of solubility was dependent on a combination of factors including the weight ratio, preparation techniques and carrier properties. The drug release data fitted well with the Weibull equation, indicating that the drug release was controlled by diffusion, polymer relaxation and erosion occurring simultaneously. Thus, these SDs, specifically CUR:P-407 1:2 w/w, can overcome the barriers of poor bioavailability to reap many beneficial properties. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

By-products from the biodiesel chain as a substrate to citric acid production by solid-state fermentation.

Science.gov (United States)

Schneider, Manuella; Zimmer, Gabriela F; Cremonese, Ezequiel B; de C de S Schneider, Rosana; Corbellini, Valeriano A

2014-07-01

In this study, we propose the use of tung cake for the production of organic acids, with an emphasis on citric acid by solid-state fermentation. We evaluated the conditions of production and the by-products from the biodiesel chain as raw materials involved in this bioprocess. First, we standardized the conditions of solid-state fermentation in tung cake with and without residual fat and with different concentrations of glycerine using the fungus Aspergillus niger The solid-state fermentation process was monitored for 7 days considering the biomass growth and pH level. Citric acid production was determined by high-performance liquid chromatography. Fungal development was better in the crude tung cake, consisting of 20% glycerine. The highest citric acid yield was 350 g kg(-1) of biomass. Therefore, the solid-state fermentation of the tung cake with glycerine led to citric acid production using the Aspergillus niger fungus. © The Author(s) 2014.

Combined Effects of Supersaturation Rates and Doses on the Kinetic-Solubility Profiles of Amorphous Solid Dispersions Based on Water-Insoluble Poly(2-hydroxyethyl methacrylate) Hydrogels.

Science.gov (United States)

Schver, Giovanna C R M; Lee, Ping I

2018-05-07

Under nonsink dissolution conditions, the kinetic-solubility profiles of amorphous solid dispersions (ASDs) based on soluble carriers typically exhibit so-called "spring-and-parachute" concentration-time behaviors. However, the kinetic-solubility profiles of ASDs based on insoluble carriers (including hydrogels) are known to show sustained supersaturation during nonsink dissolution through a matrix-regulated diffusion mechanism by which the supersaturation of the drug is built up gradually and sustained over an extended period without any dissolved polymers acting as crystallization inhibitors. Despite previous findings demonstrating the interplay between supersaturation rates and total doses on the kinetic-solubility profiles of soluble amorphous systems (including ASDs based on dissolution-regulated releases from soluble polymer carriers), the combined effects of supersaturation rates and doses on the kinetic-solubility profiles of ASDs based on diffusion-regulated releases from water-insoluble carriers have not been investigated previously. Thus, the objective of this study is to examine the impacts of total doses and supersaturation-generation rates on the resulting kinetic-solubility profiles of ASDs based on insoluble hydrogel carriers. We employed a previously established ASD-carrier system based on water-insoluble-cross-linked-poly(2-hydroxyethyl methacrylate) (PHEMA)-hydrogel beads and two poorly water soluble model drugs: the weakly acidic indomethacin (IND) and the weakly basic posaconazole (PCZ). Our results show clearly for the first time that by using the smallest-particle-size fraction and a high dose (i.e., above the critical dose), it is indeed possible to significantly shorten the duration of sustained supersaturation in the kinetic-solubility profile of an ASD based on a water-insoluble hydrogel carrier, such that it resembles the spring-and-parachute dissolution profiles normally associated with ASDs based on soluble carriers. This generates

REVIEW ON SPRAY DRIED SOLID DISPERSION

OpenAIRE

Zambre Radhika Ashok, Dr. Shendge R.S, Narode Pravin Ravindra, Sonawane Swapnil Prakash

2018-01-01

The drug solubility is the most challenging aspect for the formulation development. The poorly soluble drug has poor dissolution and absorption of drug. The low aqueous solubility of drug is required to formulate the drug into more soluble and hence bioavailable drug product. The different technique is being used to enhance the solubility of poorly water soluble drugs. Spray dried solid dispersion of drug is one of the most widely used technology to enhance the solubility of the poorly water ...

Kinetics of ascorbic acid degradation in un-pasteurized Iranian lemon juice during regular storage conditions.

Science.gov (United States)

Abbasi, A; Niakousari, M

2008-05-15

The aim of this research was to determine shelf life stability of un-pasteurized lemon juice filled in clear or dark green glass bottles. Presence of light, time and temperature affect the ascorbic acid retention in citrus juices. Bottles were stored at room temperature (27 +/- 3 degrees C) and in the refrigerator (3 +/- 1 degrees C). Total soluble solids, total titrable acidity and pH value were measured every three weeks and analysis was carried out on ascorbic acid content by means of titration method in the presence of 2,6-dichlorophenol indophenol. The study was carried out for 12 weeks after which slight changes in color, taste and apparent texture in some samples were observed and ascorbic acid content reduced by 50%. Soluble solids content, pH value and total acidity were 5.5 degrees Brix, 2.73 and 5 g/100 mL, respectively which appeared not to be significantly influenced by storage time or conditions. Ascorbic acid content initially at 38.50 mg/100 mL was sharply reduced to about 22 mg/100 mL within the first three weeks of storage. The final ascorbic acid content of all samples was about 15 mg/100 mL. The deteriorative reaction of ascorbic acid in the juice at all conditions followed a first-order kinetic model with activation energy of 137 cal mol(-1).

Structural diversity of solid dispersions of acetylsalicylic acid as seen by solid-state NMR.

Science.gov (United States)

Policianova, Olivia; Brus, Jiri; Hruby, Martin; Urbanova, Martina; Zhigunov, Alexander; Kredatusova, Jana; Kobera, Libor

2014-02-03

Solid dispersions of active pharmaceutical ingredients are of increasing interest due to their versatile use. In the present study polyvinylpyrrolidone (PVP), poly[N-(2-hydroxypropyl)-metacrylamide] (pHPMA), poly(2-ethyl-2-oxazoline) (PEOx), and polyethylene glycol (PEG), each in three Mw, were used to demonstrate structural diversity of solid dispersions. Acetylsalicylic acid (ASA) was used as a model drug. Four distinct types of the solid dispersions of ASA were created using a freeze-drying method: (i) crystalline solid dispersions containing nanocrystalline ASA in a crystalline PEG matrix; (ii) amorphous glass suspensions with large ASA crystallites embedded in amorphous pHPMA; (iii) solid solutions with molecularly dispersed ASA in rigid amorphous PVP; and (iv) nanoheterogeneous solid solutions/suspensions containing nanosized ASA clusters dispersed in a semiflexible matrix of PEOx. The obtained structural data confirmed that the type of solid dispersion can be primarily controlled by the chemical constitutions of the applied polymers, while the molecular weight of the polymers had no detectable impact. The molecular structure of the prepared dispersions was characterized using solid-state NMR, wide-angle X-ray scattering (WAXS), and differential scanning calorimetry (DSC). By applying various (1)H-(13)C and (1)H-(1)H correlation experiments combined with T1((1)H) and T1ρ((1)H) relaxation data, the extent of the molecular mixing was determined over a wide range of distances, from intimate intermolecular contacts (0.1-0.5 nm) up to the phase-separated nanodomains reaching ca. 500 nm. Hydrogen-bond interactions between ASA and polymers were probed by the analysis of (13)C and (15)N CP/MAS NMR spectra combined with the measurements of (1)H-(15)N dipolar profiles. Overall potentialities and limitations of individual experimental techniques were thoroughly evaluated.

Evaluation of soluble solids content and pH of ice cream treated with gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Rogovschi, V.D.; Nunes, T.C.F.; Fabbri, A.D.T.; Sagretti, J.M.; Sabato, S.F. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The ice cream is considered an aerated suspension of fat and ice crystals in a concentrated sugar solution containing hydrocolloids, proteins and casein micelles. Only in Brazil, in the year 2010, it was produced 1120 million liter of ice cream and due to high demand by the consumers, this is considered the most important product of the dairy industry. The objective of this work is to evaluate the soluble solids content (SSC) and the hydrogenionic potential (pH) of vanilla ice cream conditioned in isothermal boxes irradiated with 3.0 and 5.0 kGy in the Multipurpose Irradiator of {sup 60}Co located at IPEN - CNEN/SP. It can be concluded that the treatment of ice cream with gamma radiation did not cause changes in the analyzed parameters. . (author)

Evaluation of soluble solids content and pH of ice cream treated with gamma radiation

International Nuclear Information System (INIS)

Rogovschi, V.D.; Nunes, T.C.F.; Fabbri, A.D.T.; Sagretti, J.M.; Sabato, S.F.

2011-01-01

The ice cream is considered an aerated suspension of fat and ice crystals in a concentrated sugar solution containing hydrocolloids, proteins and casein micelles. Only in Brazil, in the year 2010, it was produced 1120 million liter of ice cream and due to high demand by the consumers, this is considered the most important product of the dairy industry. The objective of this work is to evaluate the soluble solids content (SSC) and the hydrogenionic potential (pH) of vanilla ice cream conditioned in isothermal boxes irradiated with 3.0 and 5.0 kGy in the Multipurpose Irradiator of 60 Co located at IPEN - CNEN/SP. It can be concluded that the treatment of ice cream with gamma radiation did not cause changes in the analyzed parameters. . (author)

Recovery of Terephthalic Acid by employing magnetic nanoparticles as a solid support

Directory of Open Access Journals (Sweden)

Elmira Ghamary

2018-03-01

Full Text Available Abstract The aim of this research work is focused on the improvement of Terephthalic acid recovery from PET wastes by using organically modified nano-Fe3O4@Cyanuric Chloride as the solid support. The performance of organically modified nano magnetic was examined in detail and the obtained results were compared with the unsupported reaction data. Required reaction time for complete glycolysis of the wastes, consumption of the solvent as well as catalyst decreases up 99%, 37.5% and 40% respectively. Result showed that nano-Fe 3O4@Cyanuric Chloride delivered good performance as solid support in depolymerizing of PET to the terephthalic acid.

The water soluble composite poly(vinylpyrrolidone–methylaniline: A new class of corrosion inhibitors of mild steel in hydrochloric acid media

Directory of Open Access Journals (Sweden)

R. Karthikaiselvi

2017-02-01

Full Text Available In recent years poly methyl aniline has been reported as one of the efficient corrosion inhibitors of mild steel in acidic media. In view of the major limitation of the insolubility of polymethyl aniline PMA, we propose to convert PMA into a water soluble composite using supporting polymer polyvinylpyrrolidone to get higher solubility and corrosion inhibition efficiency. The water soluble composite poly(vinylpyrrolidone-methyl aniline was synthesized by chemical oxidative polymerization and its inhibitive effect on mild steel in 1 M HCl has been investigated using weight loss and electrochemical techniques (potentiodynamic polarization studies and impedance spectroscopy. SEM and EDX analyses are carried out to establish a protective film formation on the metal surface.

Synthesis of water-soluble poly [acrylic acid-co-vinyl butyl ether] and its applications in cement admixtures

International Nuclear Information System (INIS)

Negim, S.M.; Mun, G.A.; Nurkeeva, Z.S.; Danveesh, H.H.M.

2005-01-01

Three composition ratios of poly[acrylic acid (AA)-co-vinyl butyl ether)] were prepared in alcoholic solution using azo-bis-isobutyro-nitrile as initiator (ABIN). The water-soluble copolymers were characterized through FT-IR, 1 H NMR, Mass spectra, ESEM as well as viscosity. The effect of water-soluble copolymers and their sodium salts on the physico-mechanical properties of Ordaniary Portland Cement (O.P.C) pastes was investigated. The results showed that the addition of aqueous solutions from the prepared copolymers and their sodium salts to the cement improve most of the specific characteristics of (O.P.C). As the concentration of the water-soluble copolymer increases, the setting time increases. The combined water content enhances the addition of copolymer to the mixing water. The compressive strength was she increased at all any hydration. The results of the solution of the prepared sodium salt copolymers are better than its copolymers. (author)

Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

International Nuclear Information System (INIS)

Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang

2007-01-01

A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid

The effect of ammonium sulfate on the solubility of amino acids in water at (298.15 and 323.15) K

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Luisa A.; Macedo, Eugenia A. [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Pinho, Simao P. [Laboratory of Separation and Reaction Engineering, Departamento de Tecnologia Quimica e Biologica, Instituto Politecnico de Braganca, Campus e Santa Apolonia, 5301-857 Braganca (Portugal)], E-mail: spinho@ipb.pt

2009-02-15

Using the analytical gravimetric method the solubility of glycine, DL-alanine, L-isoleucine, L-threonine, and L-serine in aqueous systems of (NH{sub 4}){sub 2}SO{sub 4}, at (298.15 and 323.15) K, were measured for salt concentrations ranging up to 2.0 molal. In the electrolyte molality range studied the experimental observations showed that ammonium sulfate is a salting-in agent for most of the amino acids studied. Furthermore, the change of the relative solubility with electrolyte concentration shows a maximum, which makes the representation of the data by a simple empirical correlation such as the Setschenow equation difficult. For the development and evaluation of a robust thermodynamic framework that makes it possible to more profoundly understand aqueous amino acid solutions with ammonium sulfate additional experimental information is needed.

Water-soluble dietary fibers and cardiovascular disease.

Science.gov (United States)

Theuwissen, Elke; Mensink, Ronald P

2008-05-23

One well-established way to reduce the risk of developing cardiovascular disease (CVD) is to lower serum LDL cholesterol levels by reducing saturated fat intake. However, the importance of other dietary approaches, such as increasing the intake of water-soluble dietary fibers is increasingly recognized. Well-controlled intervention studies have now shown that four major water-soluble fiber types-beta-glucan, psyllium, pectin and guar gum-effectively lower serum LDL cholesterol concentrations, without affecting HDL cholesterol or triacylglycerol concentrations. It is estimated that for each additional gram of water-soluble fiber in the diet serum total and LDL cholesterol concentrations decrease by -0.028 mmol/L and -0.029 mmol/L, respectively. Despite large differences in molecular structure, no major differences existed between the different types of water-soluble fiber, suggesting a common underlying mechanism. In this respect, it is most likely that water-soluble fibers lower the (re)absorption of in particular bile acids. As a result hepatic conversion of cholesterol into bile acids increases, which will ultimately lead to increased LDL uptake by the liver. Additionally, epidemiological studies suggest that a diet high in water-soluble fiber is inversely associated with the risk of CVD. These findings underlie current dietary recommendations to increase water-soluble fiber intake.

Long-term observation of water-soluble chemical components and acid-digested metals in the total suspended particles collected at Okinawa, Japan

Science.gov (United States)

Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Somada, Y.; Ijyu, M.; Azechi, S.; Oshiro, Y.; Nakaema, F.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

2011-12-01

The economic growth and population increase in recent Asia have been increasing air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location is ideal in observing East Asia's air quality because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background clean air and can be compared with continental air masses which have been affected by anthropogenic activities. We collected total suspended particles (TSP) on quartz filters by using a high volume air sampler at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Okinawa, Japan during August 2005 and August 2010. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations, water-soluble organic carbon (WSOC) and acid-digested metals in TSP samples using ion chromatography, atomic absorption spectrometry, total organic carbon analyzer and Inductively Coupled Plasma Mass spectrometry (ICP-MS), respectively. Seasonal variation of water-soluble chemical components and acid-digested metals showed that the concentrations were the lowest in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian continent, the concentrations of water-soluble chemical components and acid-digested metals were much higher compared to the other directions, suggesting long-range transport of air pollutants from Asian continent. Also, when the air mass came from Asian continent (75-100% dominant), the mean concentrations of non-sea salt sulfate and nitrate increased ca. 1.8 times and ca. 3.7 times, respectively between 2005 and 2010, and the ratio of nitrate to

(Solid + liquid) phase diagram for (indomethacin + nicotinamide)-methanol or methanol/ethyl acetate mixture and solubility behavior of 1:1 (indomethacin + nicotinamide) co-crystal at T = (298.15 and 313.15) K

International Nuclear Information System (INIS)

Sun, Xiaowei; Yin, Qiuxiang; Ding, Suping; Shen, Zhiming; Bao, Ying; Gong, Junbo; Hou, Baohong; Hao, Hongxun; Wang, Yongli; Wang, Jingkang; Xie, Chuang

2015-01-01

Highlights: • Ternary phase diagrams of (IMC + NCT)-methanol or methanol/ethyl acetate mixture at T = (298.15 and 313.15) K were measured. • The effects of temperature and introduced ethyl acetate on solid phase stability were discussed. • Solubility of (IMC + NCT) cocrystals was first correlated using a model considering solubility product and complexation. • Solubility of (IMC + NCT) cocrystals as a function of co-former concentration was evaluated. - Abstract: (Solid + liquid) equilibrium data for indomethacin (IMC) and nicotinamide (NCT) in both methanol (MeOH) and methanol/ethyl acetate (EA) mixture were determined using a static method at T = (298.15 and 313.15) K under atmospheric pressure. The 1:1 (IMC + NCT) co-crystal and IMC·MeOH were found in both systems under conditions investigated. The solubility of the 1:1 (IMC + NCT) co-crystal was correlated using a mathematical model consisting of both solubility product and a complexation process. Solubility of (IMC + NCT) co-crystals as a function of co-former (NCT) concentration was evaluated. It was found that temperature has a significant effect on the formation of methanol solvate in the systems investigated. Solvate formation could be suppressed either by increasing temperature or using solvent mixtures. Additionally, the solvent mixture could level out the solubility differences between IMC and NCT, resulting in larger and more symmetric regions for the (IMC + NCT) co-crystal, which would be helpful to the development of the co-crystallization process for the 1:1 (IMC + NCT) co-crystal

The acid aging as alternative process for uranium recovery from silicated ores

International Nuclear Information System (INIS)

Cipriani, M.; Della Testa, A.

1984-01-01

The influence of different variables on the extraction uranium efficiency and on the silicate solubility by means of acid aging is studied. The variables studied in bench scale were: acid/ore, oxidizing/ore and liquid/solid relationships; reaction time; temperature and recovery time. The results are discussed and compared with the ones of continuous operation of a semi-pilot plant. A flowsheet of the industrial process application is presented. (M.A.C.) [pt

Combined Measurement of 6 Fat-Soluble Vitamins and 26 Water-Soluble Functional Vitamin Markers and Amino Acids in 50 μL of Serum or Plasma by High-Throughput Mass Spectrometry.

Science.gov (United States)

Midttun, Øivind; McCann, Adrian; Aarseth, Ove; Krokeide, Marit; Kvalheim, Gry; Meyer, Klaus; Ueland, Per M

2016-11-01

Targeted metabolic profiling characterized by complementary platforms, multiplexing and low volume consumption are increasingly used for studies using biobank material. Using liquid-liquid extraction, we developed a sample workup suitable for quantification of 6 fat- and 26 water-soluble biomarkers. 50 μL of serum/plasma was mixed with dithioerythritol, ethanol, and isooctane/chloroform. The organic layer was used for analysis of the fat-soluble vitamins all-trans retinol (A), 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, α-tocopherol (E), γ-tocopherol (E), and phylloquinone (K1) by LC-MS/MS. The remaining aqueous fraction was mixed with ethanol, water, pyridine, and methylchloroformate (in toluene) to derivatize the water-soluble biomarkers. The resulting toluene layer was used for GC-MS/MS analysis of alanine, α-ketoglutarate, asparagine, aspartic acid, cystathionine, total cysteine, glutamic acid, glutamine, glycine, histidine, total homocysteine, isoleucine, kynurenine, leucine, lysine, methionine, methylmalonic acid, ornithine, phenylalanine, proline, sarcosine, serine, threonine, tryptophan, tyrosine, and valine. Isotope-labeled internal standards were used for all analytes. Chromatographic run times for the LC-MS/MS and GC-MS/MS were 4.5 and 11 min, respectively. The limits of detection (LOD) for the low-concentration analytes (25-hydroxyvitamin D2, 25-hydroxyvitamin D3, and phylloquinone) were 25, 17, and 0.33 nM, respectively, while all other analytes demonstrated sensitivity significantly lower than endogenous concentrations. Recoveries ranged from 85.5-109.9% and within- and between-day coefficients of variance (CVs) were 0.7-9.4% and 1.1-17.5%, respectively. This low-volume, high-throughput multianalyte assay is currently in use in our laboratory for quantification of 32 serum/plasma biomarkers in epidemiological studies.

Physicochemical pretreatments and hydrolysis of furfural residues via carbon-based sulfonated solid acid.

Science.gov (United States)

Ma, Bao Jun; Sun, Yuan; Lin, Ke Ying; Li, Bing; Liu, Wan Yi

2014-03-01

Potential commercial physicochemical pretreatment methods, NaOH/microwave and NaOH/ultrasound were developed, and the carbon-based sulfonated solid acid catalysts were prepared for furfural residues conversion into reducing sugars. After the two optimum pretreatments, both the content of cellulose increased (74.03%, 72.28%, respectively) and the content of hemicellulose (94.11%, 94.17% of removal rate, respectively) and lignin (91.75%, 92.09% of removal rate, respectively) decreased in furfural residues. The reducing sugar yields of furfural residues with the two physicochemical pretreatments on coal tar-based solid acid reached 33.94% and 33.13%, respectively, higher than that pretreated via NaOH alone (27%) and comparable to that pretreated via NaOH/H2O2 (35.67%). The XRD patterns, IR spectra and SEM images show microwave and ultrasound improve the pretreatment effect. The results demonstrate the carbon-based sulfonated solid acids and the physicochemical pretreatments are green, effective, low-cost for furfural residues conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

In vitro solubility of calcium, iron and zinc in relation to phytic acid levels in rice-based consumer products in China.

Science.gov (United States)

Liang, Jianfen; Han, Bei-Zhong; Nout, M J Robert; Hamer, Robert J

2010-02-01

In vitro solubility of calcium, iron and zinc in relation to phytic acid (PA) levels in 30 commercial rice-based foods from China was studied. Solubility of minerals and molar ratios of PA to minerals varied with degrees of processing. In primary products, [PA]/[Ca] values were less than 5 and [PA]/[Fe] and [PA]/[Zn] similarly ranged between 5 and 74, with most values between 20 and 30. [PA]/[mineral] molar ratios in intensively processed products were lower. Solubility of calcium ranged from 0% to 87%, with the lowest in brown rice (12%) and the highest in infant foods (50%). Iron solubility in two-thirds of samples was lower than 30%, and that of zinc narrowly ranged from 6% to 30%. Solubility of minerals was not significantly affected by [PA]/[mineral]. At present, neither primary nor intensively processed rice-based products are good dietary sources of minerals. Improvements should be attempted by dephytinization, mineral fortification or, preferably, combination of both.

Solubility and phase behaviors of DGA compounds in supercritical CO2

International Nuclear Information System (INIS)

Li Jia; Meng Qingyang

2010-01-01

Solubility and phase behaviors of DGA compounds in supercritical CO 2 (Sc-CO 2 ) was investigated. The results indicated: The dissolving ability of these six DGA compounds in Sc-CO 2 is TEDGA> TBDGA>THDGA>TODGA>TDDGA >TDdDGA; The solubility of DGA in Sc-CO 2 increase with increasing density of CO 2 , pressure and δ CO 2 ; The structure of DGA compounds is the mainly factor effected on solubility of DGA compounds in Sc-CO 2 , and the effect of hydrophobicity on solubility is much smaller than that of DGA's structure. In Sc-CO 2 , TDDGA and TDdDGA can't form the available extraction system; TEDGA and TBDGA are useful for extraction of solid powder; TODGA and THDGA are both useful for extraction of solid powder and solution contained some kind of actinide metal. (authors)

Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

Energy Technology Data Exchange (ETDEWEB)

Jiang, Tingshun, E-mail: tshjiang@mail.ujs.edu.cn; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

2014-10-15

Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH{sub 3}-TPD and N{sub 2} physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO{sub 4}{sup 2−}/Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h{sup −1} and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO{sub 4}{sup 2−}/Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO{sub 4}{sup 2−}/Zr-MCM-48-25.

JUICE EXTRACTION FOR TOTAL SOLUBLE SOLIDS CONTENT DETERMINATION IN MELON

Directory of Open Access Journals (Sweden)

Paulo Sérgio Lima e Silva

2006-01-01

Full Text Available The total soluble solids content (TSSC shows high positive correlation with sugars content, and therefore is generally accepted as an important quality trait of fruits. In melon, this evaluation is usually done by grinding a slice of the fruit's pulp in a household food processor, straining the ground material and then proceeding the TSSC determination in the resulting juice. This evaluation is labor-intensive and takes a long time to complete. An alternative process was delineated for obtaining the juice: the pulp of the fruit slice would be transversally cut one or more times, and longitudinally pressed by hand to obtain the juice. The objective of this work was to compare processes for obtaining juice to evaluate TSSC in melons. Fifty, 15, and 15 fruits of the Galia, Yellow, and Cantaloupe type melons were evaluated, respectively. Each fruit was considered as a block, and was longitudinally split into six fractions with similar sizes, which corresponded to the plots. The following treatments were evaluated: fraction without cuts, fractions with one, three, five, or seven transversal cuts, and the fraction treated by the conventional process. It was concluded that the procedure by which the melon slices of Galia, Yellow and Cantaloupe types are pressed for obtaining the juice to evaluate TSSC can overestimate this content. This would probably be due to the fact that the most internal section of the mesocarp presents greater TSSC than the portions closer to the epicarp.

An Introduction to the Understanding of Solubility.

Science.gov (United States)

Letcher, Trevor M.; Battino, Rubin

2001-01-01

Explores different solubility processes and related issues, including the second law of thermodynamics and ideal mixtures, real liquids, intermolecular forces, and solids in liquids or gases in liquids. (Contains 22 references.) (ASK)

Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

Energy Technology Data Exchange (ETDEWEB)

Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

2008-10-15

The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

Energy Technology Data Exchange (ETDEWEB)

Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2015-01-26

High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm{sup 2}/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

Directory of Open Access Journals (Sweden)

Rongning Liang

2018-03-01

Full Text Available Nowadays, it is still difficult for molecularly imprinted polymers (MIPs to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

Science.gov (United States)

Liang, Rongning; Wang, Tiantian; Zhang, Huan; Yao, Ruiqing; Qin, Wei

2018-03-01

Nowadays, it is still difficult for molecularly imprinted polymer (MIPs) to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

Molybdenum solubility in aluminium nitrate solutions

Energy Technology Data Exchange (ETDEWEB)

Heres, X.; Sans, D.; Bertrand, M.; Eysseric, C. [CEA, Centre de Marcoule, Nuclear Energy Division, DRCP, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Brackx, E.; Domenger, R.; Excoffier, E. [CEA, Centre de Marcoule, Nuclear Energy Division, DTEC, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Valery, J.F. [AREVA-NC, DOR/RDP, Paris - La Defense (France)

2016-07-01

For over 60 years, research reactors (RR or RTR for research testing reactors) have been used as neutron sources for research, radioisotope production ({sup 99}Mo/{sup 99m}Tc), nuclear medicine, materials characterization, etc... Currently, over 240 of these reactors are in operation in 56 countries. They are simpler than power reactors and operate at lower temperature (cooled to below 100 C. degrees). The fuel assemblies are typically plates or cylinders of uranium alloy and aluminium (U-Al) coated with pure aluminium. These fuels can be processed in AREVA La Hague plant after batch dissolution in concentrated nitric acid and mixing with UOX fuel streams. The aim of this study is to accurately measure the solubility of molybdenum in nitric acid solution containing high concentrations of aluminium. The higher the molybdenum solubility is, the more flexible reprocessing operations are, especially when the spent fuels contain high amounts of molybdenum. To be most representative of the dissolution process, uranium-molybdenum alloy and molybdenum metal powder were dissolved in solutions of aluminium nitrate at the nominal dissolution temperature. The experiments showed complete dissolution of metallic elements after 30 minutes long stirring, even if molybdenum metal was added in excess. After an induction period, a slow precipitation of molybdic acid occurs for about 15 hours. The data obtained show the molybdenum solubility decreases with increasing aluminium concentration. The solubility law follows an exponential relation around 40 g/L of aluminium with a high determination coefficient. Molybdenum solubility is not impacted by the presence of gadolinium, or by an increasing concentration of uranium. (authors)

Enhancement of solubility, dissolution release profile and reduction in ulcerogenicity of piroxicam by inclusion complex with skimmed milk.

Science.gov (United States)

Sanka, Krishna; Munjulury, Venkata Saidheeraj; Mohd, Abdul Bari; Diwan, Prakash V

2014-11-01

Piroxicam (PXM), a non-steroidal anti-inflammatory drug which is poorly soluble in water and ulcerogenic. Milk has been used against the gastric disturbances caused by non-steroidal anti-inflammatory drugs. In this study, skimmed milk (SKM) is used as the carrier for inclusion complex (IC) due to its surface active agent and amino acid content. To enhance the solubility, dissolution rate and prevent ulcerogenicity of PXM though IC with SKM. IC of PXM were prepared with SKM by solvent evaporation method using rota evaporator and were evaluated for solubility, dissolution, solid state characterization, drug excipient interaction, rat intestinal permeation, ulcerogenicity and histopathological studies. Solubility of PXM was enhanced 2.5 times with IC. The dissolution release and amount of PXM permeated through rat small intestine was enhanced significantly with IC. Decreases in the gastric lesion index values of IC were observed than physical mixture (PM) and free PXM. The histopathological studies revealed significant reduction in ulceration in rat stomach after treatment with IC. It is concluded that SKM is a good carrier to prepare IC of PXM for oral administration.

Preparation and Characterization of a Solid Acid Catalyst from Macro Fungi Residue for Methyl Palmitate Production

Directory of Open Access Journals (Sweden)

Min Wang

2015-07-01

Full Text Available During the process of fungal polysaccharide extraction for health care products and food factories, a large quantity of macro-fungi residues are produced, but most of the residues are abandoned and become environmental pollutants. A solid acid catalyst, prepared by sulfonating carbonized Phellinus igniarius residue, was shown to be an efficient and environmentally benign catalyst for the esterification of palmitate acid (PA and methanol. As a comparison, two types of common biomass catalysts, wheat straws and wood chips, were prepared. In this study, characterizations, including scanning electron microscopy, thermo-gravimetric analysis, Fourier transform infrared spectrometry, Brunauer-Emmett-Teller assays and elemental analysis, and reaction conditions for the synthesis of methyl palmitate (MP using solid acid catalysts were investigated. Experiments showed that the solid acid catalyst prepared from P. igniarius residue had a higher catalytic activity than the other two catalysts, and the highest yield of MP catalyzed by P. igniarius residue solid acid catalyst was 91.5% under the following optimum conditions: molar ratio of methanol/PA of 10:1, reaction temperature of 60 °C, mass ratio of catalyst/substrate of 2%, and a reaction time of 1.5 h. Thus, the use of this catalyst offers a method for producing MP.

Peculiarities of hydrogen permeation through Zr–1%Nb alloy and evaluation of terminal solid solubility

Energy Technology Data Exchange (ETDEWEB)

Denisov, E.A.; Kompaniets, M.V.; Kompaniets, T.N., E-mail: tkompaniets@spbu.ru; Bobkova, I.S.

2016-04-15

Hydrogen permeation through Zr–1%Nb alloy was studied at the temperature below the temperature of α-β transition. Analysis of the transient permeation curves from a closed volume in a surface limited regime allowed to determine total and mobile hydrogen concentrations. At the mobile hydrogen concentration of 4.3 at% a part of the absorbed hydrogen is cut out of permeation process. Increase of the mobile hydrogen concentration in α-phase of Zr–1%Nb alloy is ceasing at the concentration of (5.5 ± 0.3) at%, which is the maximum possible concentration of the mobile hydrogen in α-phase of the studied alloy. From this moment on all absorbed hydrogen is spent on hydride formation. The obtained results are compared with those obtained by means of traditional techniques for terminal solid solubility determination.

Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in Shanghai, China.

Science.gov (United States)

Li, Fei; Zhang, Chaojie; Qu, Yan; Chen, Jing; Chen, Ling; Liu, Ying; Zhou, Qi

2010-01-01

Perfluorinated acids (PFAs) have been recognized as emerging environmental pollutants because of their widespread occurrences, persistence, and bioaccumulative and toxicological effects. PFAs have been detected in aquatic environment and biota in China, but the occurrences of these chemicals have not been reported in solid matrices in China. In the present study, short- and long-chain PFAs (C2-C14) have been quantitatively determined in solid matrices including sediments, soils and sludge collected in Shanghai, China. The results indicate that sludge contains more PFAs than sediments and soils, and the total PFAs concentrations in sediments, soil and sludge are 62.5-276 ng g(-1), 141-237 ng g(-1) and 413-755 ng g(-1), respectively. In most cases, trifluoroacetic acid was the major PFA and accounted for 22-90% of the total PFAs. Although the levels of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) were not only lower than trifluoroacetic acid, but also lower than some short-chain PFCAs (PFAs, respectively. Meanwhile, unlike previous studies, PFOS levels were not always higher than PFOA in solids collected in Shanghai, China. Given that some short-chain PFAs such as trifluoroacetic acid are mildly phytotoxic and their higher levels in solid matrices were collected in Shanghai, China, these chemicals should be included in future environmental monitoring efforts.

Heavy metal speciation in solid-phase materials from a bacterial sulfate reducing bioreactor using sequential extraction procedure combined with acid volatile sulfide analysis.

Science.gov (United States)

Jong, Tony; Parry, David L

2004-04-01

Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be

Effect of whey protein isolate films incorporated with montmorillonite and citric acid on the preservation of fresh-cut apples.

Science.gov (United States)

Azevedo, Viviane Machado; Dias, Marali Vilela; de Siqueira Elias, Heloisa Helena; Fukushima, Katia Lumi; Silva, Eric Keven; de Deus Souza Carneiro, João; de Fátima Ferreira Soares, Nilda; Borges, Soraia Vilela

2018-05-01

The objective of this paper was to evaluate the effect of bioactive whey protein isolate/montmorillonite films containing citric acid on the inhibition of enzymatic browning and physicochemical properties in minimally processed apples. Whey protein isolate films incorporated with montmorillonite (3 g/100 g) and citric acid (5 and 10 g/100 g) were applied to the apples slices. All samples were packaged in polypropylene trays (14.6 cm × 11.4 cm × 6.5 cm) and stored at 5 ± 2 °C and 85 ± 3% RH for eight days. Every two days, the apples samples were evaluated for color, acidity, pH, soluble solids, water activity and polyphenol oxidase and peroxidase enzyme activity. The enzymatic browning of the apples slices was reduced for all films during storage. However, the films containing citric acid maintained the color characteristics, reducing the loss of quality associated the maintenance of acidity, soluble solids, water activity, reduction of polyphenol oxidase and peroxidase activity, thus prolonging the shelf life of the apples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pretreatment of dried distillers grains with solubles by soaking in aqueous ammonia and subsequent enzymatic/dilute acid hydrolysis to produce fermentable sugars

Science.gov (United States)

Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15% w/w NH4OH solution at a solid:liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied...

PEI detoxification of pretreated spruce for high solids ethanol fermentation

International Nuclear Information System (INIS)

Cannella, David; Sveding, Per Viktor; Jørgensen, Henning

2014-01-01

Highlights: • High solids (30% dry matter) pretreatment, enzymatic hydrolysis and fermentation. • Horizontal rotary reactor for hydrolysis and fermentation. • In situ hydrolysates detoxification using inhibitors adsorbing PEI polymer. • 50% of inhibitors recovered as by-product, recyclability of PEI polymer up to 5 times. • 76% of maximum theoretical ethanol was fermented at final concentration of 51 g/kg. - Abstract: Performing the bioethanol production process at high solids loading is a requirement for economic feasibility at industrial scale. So far this has successfully been achieved using wheat straw and other agricultural residues at 30% of water insoluble solids (WIS), but for softwood species (i.e. spruce) this has been difficult to reach. The main reason behind this difference is the higher recalcitrance of woody substrates which require harsher pretreatment conditions, thus generating higher amounts of inhibitory compounds, ultimately lowering fermentation performances. In this work we studied ethanol production from spruce performing the whole process, from pretreatment to hydrolysis and fermentation, at 30% dry matter (equivalent to ∼20% WIS). Hydrolysis and fermentation was performed in a horizontal free fall mixing reactor enabling efficient mixing at high solids loadings. In batch simultaneous saccharification and fermentation (SSF), up to 76% cellulose to ethanol conversion was achieved resulting in a concentration of 51 g/kg of ethanol. Key to obtaining this high ethanol yield at these conditions was the use of a detoxification technology based on applying a soluble polyelectrolyte polymer (polyethylenimine, PEI) to absorb inhibitory compounds in the material. On average 50% removal and recovery of the main inhibitors (HMF, furfural, acetic acid and formic acid) was achieved dosing 1.5% w/w of soluble PEI. The use of PEI was compatible with operating the process at high solids loadings and enabled fermentation of hydrolysates, which

Separation of phenolic acids from sugarcane rind by online solid-phase extraction with high-speed counter-current chromatography.

Science.gov (United States)

Geng, Ping; Fang, Yingtong; Xie, Ronglong; Hu, Weilun; Xi, Xingjun; Chu, Qiao; Dong, Genlai; Shaheen, Nusrat; Wei, Yun

2017-02-01

Sugarcane rind contains some functional phenolic acids. The separation of these compounds from sugarcane rind is able to realize the integrated utilization of the crop and reduce environment pollution. In this paper, a novel protocol based on interfacing online solid-phase extraction with high-speed counter-current chromatography (HSCCC) was established, aiming at improving and simplifying the process of phenolic acids separation from sugarcane rind. The conditions of online solid-phase extraction with HSCCC involving solvent system, flow rate of mobile phase as well as saturated extent of absorption of solid-phase extraction were optimized to improve extraction efficiency and reduce separation time. The separation of phenolic acids was performed with a two-phase solvent system composed of butanol/acetic acid/water at a volume ratio of 4:1:5, and the developed online solid-phase extraction with HSCCC method was validated and successfully applied for sugarcane rind, and three phenolic acids including 6.73 mg of gallic acid, 10.85 mg of p-coumaric acid, and 2.78 mg of ferulic acid with purities of 60.2, 95.4, and 84%, respectively, were obtained from 150 mg sugarcane rind crude extracts. In addition, the three different elution methods of phenolic acids purification including HSCCC, elution-extrusion counter-current chromatography and back-extrusion counter-current chromatography were compared. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrospun 4th-Generation Solid Dispersions of Poorly Water-Soluble Drug Utilizing Two Different Processes

Directory of Open Access Journals (Sweden)

Zhu Zhang

2018-01-01

Full Text Available Different from traditional solid dispersion (SD for improving the dissolution rates of poorly water-soluble drugs, the upgraded 4th SD was developed to furnish a drug sustained-release profile. In this work, two different kinds of 4th SDs were fabricated using two electrospinning processes. One is a ternary SD (nanofibers F2 that consisted of ethyl cellulose (EC, polyethylene glycol 1000 (PEG, and tamoxifen citrate (TAM from a modified coaxial process, and the other is a binary SD (nanofibers F1 which is comprised of EC and TAM from a single-fluid blending process. Scanning electronic microscopic observations demonstrated that F2 (330±50 nm showed a better quality than F1 (870±230 nm in terms of size and size distribution although both of them had a smooth surface morphology and a cross section. X-ray diffraction patterns verified that both SDs were amorphous nanocomposites owing to the favorable secondary interactions among these components, as suggested from the results of FTIR. In vitro dissolution experiments indicated that F2 could furnish an improved drug sustained-release characteristics compared to F1, exhausting all the contained TAM and having weaker leveling-off late release. The molecular behaviors of drug sustained-release from the binary 4th SD were suggested. The protocols reported here paved an alternative way for developing novel functional nanomaterials for effective delivery of poorly water-soluble drugs.

Solubility of solid ferrocene in pressurized hot water

Czech Academy of Sciences Publication Activity Database

Karásek, Pavel; Hohnová, Barbora; Planeta, Josef; Roth, Michal

2010-01-01

Roč. 55, č. 8 (2010), s. 2866-2869 ISSN 0021-9568 R&D Projects: GA ČR GA203/07/0886; GA ČR GA203/08/1465; GA ČR GA203/08/1536 Institutional research plan: CEZ:AV0Z40310501 Keywords : pressurized hot water * ferrocene * solubility Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.089, year: 2010

Enhancement of Solubility and Bioavailability of Candesartan ...

African Journals Online (AJOL)

Purpose: To enhance the otherwise poor solubility and bioavailability of candesartan cilexetil (CDS). Methods: This ... PEG 6000-based solid dispersions showed 1st order drug release kinetics. ..... the liver due to quercetin's inhibitory effect on.

Solubilities of some hydrous REE phosphates with implications for diagenesis and sea water concentrations

International Nuclear Information System (INIS)

Jonasson, R.G.; Bancroft, G.M.; Nesbitt, H.W.

1985-01-01

Solubility product determinations suggest that the hydrous phosphates of the rare earths, REPO 4 .xH 2 O, are important in controlling the sea water REE concentrations. Two of these solids, rhabdophane, (P6 2 22) and 'hydrous xenotime', (I4 1 /amd), have been synthesized at 100 C via the acid hydrolysis of the respective REE pyrophosphate. The solubility products at infinite dilution were determined to be pK 0 = 24.5, (La at 25 C); 26.0, (Pr at 100 C); 25.7, (Nd at 100 C); and 25.5, (Er at 100 C). On the basis of calculations involving the reaction of Re 3+ with apatite to form the hydrous phosphate, the lanthanum concentration in sea water is predicted to be about 140 pmol/L. Laboratory experiments support the hypothesis that apatite is a substrate for reactions with dissolved REE. (author)

Small acid soluble proteins for rapid spore identification.

Energy Technology Data Exchange (ETDEWEB)

Branda, Steven S.; Lane, Todd W.; VanderNoot, Victoria A.; Jokerst, Amanda S.

2006-12-01

This one year LDRD addressed the problem of rapid characterization of bacterial spores such as those from the genus Bacillus, the group that contains pathogenic spores such as B. anthracis. In this effort we addressed the feasibility of using a proteomics based approach to spore characterization using a subset of conserved spore proteins known as the small acid soluble proteins or SASPs. We proposed developing techniques that built on our previous expertise in microseparations to rapidly characterize or identify spores. An alternative SASP extraction method was developed that was amenable to both the subsequent fluorescent labeling required for laser-induced fluorescence detection and the low ionic strength requirements for isoelectric focusing. For the microseparations, both capillary isoelectric focusing and chip gel electrophoresis were employed. A variety of methods were evaluated to improve the molecular weight resolution for the SASPs, which are in a molecular weight range that is not well resolved by the current methods. Isoelectric focusing was optimized and employed to resolve the SASPs using UV absorbance detection. Proteomic signatures of native wild type Bacillus spores and clones genetically engineered to produce altered SASP patterns were assessed by slab gel electrophoresis, capillary isoelectric focusing with absorbance detection as well as microchip based gel electrophoresis employing sensitive laser-induced fluorescence detection.

Influence of organic matter on the solubility of ThO2 and geochemical modeling

International Nuclear Information System (INIS)

Liu Dejun; Luo Tian; Maes, N.; Bruggeman, C.

2014-01-01

Thorium (IV) is widely considered in laboratory experiments as a suitable chemical analogue for long-lived tetravalent actinides. Th (IV) is redox-insensitive, as an analogue for U (IV) to study the influence of natural organic matter on the solubility. The solubility of crystalline ThO 2 (cr) has been measured under geochemical conditions representative for the Boom Clay using Real Boom Clay Water containing organic matter to assess its influence on the ThO 2 (cr) solubility. For the purpose of comparison, Aldrich Humic Acid was also investigated. Solubility measurements of ThO 2 (cr) were approached from under-saturation in an anaerobic glove box with a controlled Ar0.4%CO 2 atmosphere. Th concentration is determined after 30000 MWCO, 300000 MWCO, and 0.45 μm filtration to distinguish solid (0.45 μm), larger colloids (300000 MWCO), and small dissolved species(30000 MWCO). X-ray diffraction was carried out to investigate the transformation of ThO 2 (cr) phase during the contact with Boom Clay Water. In Synthetic Boom Clay Water (without organic matter) the concentrations of Th (IV) are 5 × l0 -ll mol/L, 4 × lO -10 mol/L, and 8 × lO -8 mol/L after 30000 MWCO, 300000 MWCO, and 0. 45 μm filtration, respectively. It indicated the existence of inorganic colloids in solution. The increase of the total Th solution concentration with increasing organic matter concentration revealed a complexation-like interaction between Th and organic matter. All the experimental data could be modeled by Tipping humic ion-binding model VI using a combination of solubility calculations and complexation reactions between Th (IV) and organic matter functional groups. Similar to the investigation of Eu 3+ solubility, the affinity of organic matter for Th was higher for Aldrich humic acid compared to Boom Clay organic matter. However, Boom Clay organic matter with different size had the similar complexation affinity with Th (IV). (authors)

Chromium–tungsten–titanium mixed oxides solid catalyst for fatty acid methyl ester synthesis from palm fatty acid distillate

International Nuclear Information System (INIS)

Wan, Zuraida; Hameed, B.H.

2014-01-01

Highlights: • Chromium–tungsten–titanium mixed oxides as solid catalyst. • Catalyst used for esterification of palm fatty acid distillate to methyl esters. • The maximum methyl ester content is 83%. • Catalyst has shown good activity and can be recycled for 4 times. - Abstract: Chromium–tungsten–titanium mixed oxides solid catalysts were prepared and evaluated in the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). Esterification was conducted in a batch reactor at 110–200 °C temperature ranges. The catalysts were characterized by several techniques such as BET, TEM, FTIR, TGA, XRD, EDX and SEM. The treatment conditions during catalyst preparation, effect of reaction parameters, leaching of the active species and the recycled use of the catalyst were investigated. The catalyst with formula CrWTiO 2 was found to be the most active with maximum FAME content of 83% obtained at best reaction conditions of 170 °C for 3 h, 2:1 (methanol to oil molar ratio) and 2 wt.% catalyst dosage. The catalyst can be recycled for 4 times. The results revealed CrWTiO 2 good potentials for use in esterification of high acid value oil

A new synthetic methodology for the preparation of biocompatible and organo-soluble barbituric- and thiobarbituric acid based chitosan derivatives for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Shahzad, Sohail [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Shahzadi, Lubna [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Mahmood, Nasir [Department of Allied Health Sciences and Chemical Pathology, Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore (Pakistan); Siddiqi, Saadat Anwar [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Rauf, Abdul [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Manzoor, Faisal; Chaudhry, Aqif Anwar [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Rehman, Ihtesham ur [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Materials Science and Engineering, The Kroto Research Institute, The University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ (United Kingdom); Yar, Muhammad, E-mail: drmyar@ciitlahore.edu.pk [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan)

2016-09-01

Chitosan's poor solubility especially in organic solvents limits its use with other organo-soluble polymers; however such combinations are highly required to tailor their properties for specific biomedical applications. This paper describes the development of a new synthetic methodology for the synthesis of organo-soluble chitosan derivatives. These derivatives were synthesized from chitosan (CS), triethyl orthoformate and barbituric or thiobarbituric acid in the presence of 2-butannol. The chemical interactions and new functional motifs in the synthesized CS derivatives were evaluated by FTIR, DSC/TGA, UV/VIS, XRD and {sup 1}H NMR spectroscopy. A cytotoxicity investigation for these materials was performed by cell culture method using VERO cell line and all the synthesized derivatives were found to be non-toxic. The solubility analysis showed that these derivatives were readily soluble in organic solvents including DMSO and DMF. Their potential to use with organo-soluble commercially available polymers was exploited by electrospinning; the synthesized derivatives in combination with polycaprolactone delivered nanofibrous membranes. - Highlights: • Development of a new synthetic methodology • Synthesis of organo-soluble chitosan (CS) derivatives • VERO cells proliferation • Nanofibrous membranes from the synthesized chitosan derivatives and polycaprolactone.

Determination of water-soluble vitamins using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts.

Science.gov (United States)

Tsukatani, Tadayuki; Suenaga, Hikaru; Ishiyama, Munetaka; Ezoe, Takatoshi; Matsumoto, Kiyoshi

2011-07-15

A method for the determination of water-soluble vitamins using a colorimetric microbial viability assay based on the reduction of the tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt (WST-8)} via 2-methyl-1,4-napthoquinone (NQ) was developed. Measurement conditions were optimized for the microbiological determination of water-soluble vitamins, such as vitamin B(6), biotin, folic acid, niacin, and pantothenic acid, using microorganisms that have a water-soluble vitamin requirement. A linear relationship between absorbance and water-soluble vitamin concentration was obtained. The proposed method was applied to determine the concentration of vitamin B(6) in various foodstuffs. There was good agreement between vitamin B(6) concentrations determined after 24h using the WST-8 colorimetric method and those obtained after 48h using a conventional method. The results suggest that the WST-8 colorimetric assay is a useful method for the rapid determination of water-soluble vitamins in a 96-well microtiter plate. Copyright © 2011 Elsevier Ltd. All rights reserved.

Soluble adenylyl cyclase is an acid-base sensor in epithelial base-secreting cells.

Science.gov (United States)

Roa, Jinae N; Tresguerres, Martin

2016-08-01

Blood acid-base regulation by specialized epithelia, such as gills and kidney, requires the ability to sense blood acid-base status. Here, we developed primary cultures of ray (Urolophus halleri) gill cells to study mechanisms for acid-base sensing without the interference of whole animal hormonal regulation. Ray gills have abundant base-secreting cells, identified by their noticeable expression of vacuolar-type H(+)-ATPase (VHA), and also express the evolutionarily conserved acid-base sensor soluble adenylyl cyclase (sAC). Exposure of cultured cells to extracellular alkalosis (pH 8.0, 40 mM HCO3 (-)) triggered VHA translocation to the cell membrane, similar to previous reports in live animals experiencing blood alkalosis. VHA translocation was dependent on sAC, as it was blocked by the sAC-specific inhibitor KH7. Ray gill base-secreting cells also express transmembrane adenylyl cyclases (tmACs); however, tmAC inhibition by 2',5'-dideoxyadenosine did not prevent alkalosis-dependent VHA translocation, and tmAC activation by forskolin reduced the abundance of VHA at the cell membrane. This study demonstrates that sAC is a necessary and sufficient sensor of extracellular alkalosis in ray gill base-secreting cells. In addition, this study indicates that different sources of cAMP differentially modulate cell biology. Copyright © 2016 the American Physiological Society.

Characteristics of immobilized lactobacillus delbrueckii in a liquid-solid fluidized bed bioreactor for lactic acid production

Energy Technology Data Exchange (ETDEWEB)

Wang, Henian; Seki, M.; Furusaki, S. [The Univ. of Tokyo (Japan). Faculty of Engineering

1995-04-20

A fluidized bed bioreactor was employed for lactic acid production using immobilized cells. First, the cell release rate was discussed. A liquid-solid fluidized bed reactor with immobilized cells was used to perform continuous lactic acid fermentation without any operational problems. The performance of the reactor was investigated under different conditions. Cell release rate and contribution of free cells to lactic acid production were studied quantitatively. The results showed that under low gel holdup and low dilution rate conditions, free cells played a significant role in lactic acid production. However, increasing solid holdup decreased the free cell concentration in the broth due to high lactic acid concentration and also decreased the contribution of the free cells to lactic acid production. The effects of growth nutrients on reactor performance were investigated. 16 refs., 12 figs.

Ash behavior during hydrothermal treatment for solid fuel applications. Part 2: Effects of treatment conditions on industrial waste biomass

International Nuclear Information System (INIS)

Mäkelä, Mikko; Yoshikawa, Kunio

2016-01-01

Highlights: • Effect of treatment conditions on composition and solubility of ash. • Ash dissolution and yield governed by liquid pH and calcium carbonate solubility. • Dissolution of calcium carbonate decreases ash fusion temperature during combustion. • Decreasing the ash content of sludge can weaken ash properties for combustion. - Abstract: This second half of our work on ash behavior concentrates on the effects of hydrothermal treatment conditions on paper sludge. Ash composition and solubility were determined based on treatment temperature, reactor solid load and liquid pH using experimental design and univariate regression methods. In addition, ash properties for combustion were evaluated based on recent developments on ash classification. Based on the results, all experimental variables had a statistically significant effect on ash yields. Only reactor solid load was statistically insignificant for char ash content, which increased based on increasing treatment temperature due to the decomposition of organic components. Ash dissolution and ash yield were governed by liquid pH and the generation of acids mainly due to the solubility of calcium carbonate identified as the main mineral species of paper sludge. Dissolution of calcium carbonate however decreased ash fusion temperatures more likely causing problems during char incineration. This indicated that decreasing the ash content of sludge during hydrothermal treatment can actually weaken ash properties for solid fuel applications.

Assessment of two kinetic tests to predict the acid mine drainage in waste rock samples of a uranium mine

OpenAIRE

Abreu,Adriana Trópia de; Faria,Efigênia Miranda de; Chaves,Carla Thamilis Fonseca; Leite,Adilson do Lago; Lena,Jorge Carvalho de

2014-01-01

Acid mine drainage is the result of the oxidation process of sulfide bearing rocks. This process occurs when the sulfide material is exposed to atmospheric conditions. Under these conditions, successive oxidation reactions yield sulfuric acid generating acidic waters. This problem becomes more serious when the surrounding rocks are not able to neutralize the acid. The low pH condition of the drained water accelerates the solubility process of solid materials (rocks, soils and sediments) and f...

Enhanced solubility and targeted delivery of curcumin by lipopeptide micelles.

Science.gov (United States)

Liang, Ju; Wu, Wenlan; Lai, Danyu; Li, Junbo; Fang, Cailin

2015-01-01

A lipopeptide (LP)-containing KKGRGDS as the hydrophilic heads and lauric acid (C12) as the hydrophobic tails has been designed and prepared by standard solid-phase peptide synthesis technique. LP can self-assemble into spherical micelles with the size of ~30 nm in PBS (phosphate buffer saline) (pH 7.4). Curcumin-loaded LP micelles were prepared in order to increase the water solubility, sustain the releasing rate, and improve the tumor targeted delivery of curcumin. Water solubility, cytotoxicity, in vitro release behavior, and intracellular uptake of curcumin-loaded LP micelles were investigated. The results showed that LP micelles can increase the water solubility of curcumin 1.1 × 10(3) times and sustain the release of curcumin in a low rate. Curcumin-loaded LP micelles showed much higher cell inhibition than free curcumin on human cervix carcinoma (HeLa) and HepG2 cells. When incubating these curcumin-loaded micelles with HeLa and COS7 cells, due to the over-expression of integrins on cancer cells, the micelles can efficiently use the tumor-targeting function of RGD (functionalized peptide sequences: Arg-Gly-Asp) sequence to deliver the drug into HeLa cells, and better efficiency of the self-assembled LP micelles for curcumin delivery than crude curcumin was also confirmed by LCSM (laser confocal scanning microscope) assays. Combined with the enhanced solubility and higher cell inhibition, LP micelles reported in this study may be promising in clinical application for targeted curcumin delivery.

Maleic acid treatment of biologically detoxified corn stover liquor.