Uptake of Hypobromous Acid (HOBr) by Aqueous Sulfuric Acid Solutions: Low-Temperature Solubility and Reaction

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Michelsen, Rebecca R.; Ashbourn, Samatha F. M.; Rammer, Thomas A.; Golden, David M.

2005-01-01

Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45 - 70 wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H* = 10(exp 4) - 10(exp 7) mol/L/atm. H* is inversely dependent on temperature, with Delta H = -46.2 kJ/mol and Delta S = -106.2 J/mol/K for 55 - 70 wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into aqueous 45 wt% H2SO4, the solubility can be described by log H* = 3665/T - 10.63. For 55 - 70 wt% H2SO4, log H* = 2412/T - 5.55. At temperatures colder than approx. 213 K, the solubility of HOBr in 45 wt% H2SO4 is noticeably larger than in 70 wt% H2SO4. The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Our measurements indicate chemical reaction of HOBr upon uptake into aqueous sulfuric acid in the presence of other brominated gases followed by evolution of gaseous products including Br2O and Br2, particularly at 70 wt% H2SO4.

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

PubMed

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.

Oral water soluble contrast for the management of adhesive small bowel obstruction.

PubMed

Abbas, S; Bissett, I P; Parry, B R

2007-07-18

Adhesions are the leading cause of small bowel obstruction. Gastrografin transit time may allow for the selection of appropriate patients for non-operative management. Some studies have shown when the contrast does not reach the colon after a designated time it indicates complete intestinal obstruction that is unlikely to resolve with conservative treatment. When the contrast does reach the large bowel, it indicates partial obstruction and patients are likely to respond to conservative treatment. Other studies have suggested that the administration of water-soluble contrast is therapeutic in resolving the obstruction. To determine the reliability of water-soluble contrast media and serial abdominal radiographs in predicting the success of conservative treatment in patients admitted with adhesive small bowel obstruction.Furthermore, to determine the efficacy and safety of water-soluble contrast media in reducing the need for surgical intervention and reducing hospital stay in adhesive small bowel obstruction. The search was conducted using MESH terms: ''Intestinal obstruction'', ''water-soluble contrast'', "Adhesions" and "Gastrografin". The later combined with the Cochrane Collaboration highly sensitive search strategy for identifying randomised controlled trials and controlled clinical trials. 1. Prospective studies were included to evaluate the diagnostic potential of water-soluble contrast in adhesive small bowel obstruction.2. Randomised clinical trials were selected to evaluate the therapeutic role. 1. Studies that addressed the diagnostic role of water-soluble contrast were critically appraised and data presented as sensitivities, specificities and positive and negative likelihood ratios. Results were pooled and summary ROC curve was constructed.2. A meta-analysis of the data from therapeutic studies was performed using the Mantel -Henszel test using both the fixed effect and random effect models. The appearance of water-soluble contrast in the colon on an

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

PubMed Central

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.

PubMed

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.

Changing Atmospheric Acidity and the Oceanic Solubility of Nutrients

NASA Astrophysics Data System (ADS)

Baker, Alex; Sarin, Manmohan; Duce, Robert; Jickells, Tim; Kanakidou, Maria; Myriokefalitakis, Stelios; Ito, Akinori; Turner, David; Mahowald, Natalie; Middag, Rob; Guieu, Cecile; Gao, Yuan; Croot, Peter; Shelley, Rachel; Perron, Morgane

2017-04-01

The atmospheric deposition of nutrients to the ocean is known to play a significant role in the marine carbon cycle. The impact of such deposition is dependent on the identity of the nutrient in question (e.g., N, P, Fe, Co, Zn, Ni, Cd), the location of the deposition, and the bioavailability of the deposited nutrient. Bioavailability is largely governed by the chemical speciation of a nutrient and, in general, insoluble species are not bioavailable. For Fe and P (and perhaps the other nutrient trace metals) solubility increases during transport through the atmosphere. The causes of this increase are complex, but interactions of aerosol particles with acids appears to play a significant role. Emissions of acidic (SO2 and NOx) and alkaline (NH3) gases have increased significantly since the Industrial Revolution, with a net increase in atmospheric acidity. This implies that Fe and P solubility may also have increased over this time period, potentially resulting in increased marine productivity. More recently, pollution controls have decreased emissions of SO2 from some regions and further reductions in SO2 and NOx are likely in the future. Emissions of NH3 are much more difficult to control however, and are projected to stabilise or increase slightly to the end of this century. Future anthropogenic emissions are thus likely to change the acidity of the atmosphere downwind of major urban / industrial centres, with potential consequences for the supply of soluble nutrients to the ocean. To address these issues UN/GESAMP Working Group 38, The Atmospheric Input of Chemicals to the Ocean, is convening a workshop on this topic at the University of East Anglia in February, 2017. The goals of this workshop are to review and synthesize the current scientific information on the solubility of aerosol-associated key biogeochemical elements, the biogeochemical controls on aerosol solubility, and the pH sensitivity of those controls; to consider the likely changes in solubility of

Amino acid contribution to protein solubility: Asp, Glu, and Ser contribute more favorably than the other hydrophilic amino acids in RNase Sa.

PubMed

Trevino, Saul R; Scholtz, J Martin; Pace, C Nick

2007-02-16

Poor protein solubility is a common problem in high-resolution structural studies, formulation of protein pharmaceuticals, and biochemical characterization of proteins. One popular strategy to improve protein solubility is to use site-directed mutagenesis to make hydrophobic to hydrophilic mutations on the protein surface. However, a systematic investigation of the relative contributions of all 20 amino acids to protein solubility has not been done. Here, 20 variants at the completely solvent-exposed position 76 of ribonuclease (RNase) Sa are made to compare the contributions of each amino acid. Stability measurements were also made for these variants, which occur at the i+1 position of a type II beta-turn. Solubility measurements in ammonium sulfate solutions were made at high positive net charge, low net charge, and high negative net charge. Surprisingly, there was a wide range of contributions to protein solubility even among the hydrophilic amino acids. The results suggest that aspartic acid, glutamic acid, and serine contribute significantly more favorably than the other hydrophilic amino acids especially at high net charge. Therefore, to increase protein solubility, asparagine, glutamine, or threonine should be replaced with aspartic acid, glutamic acid or serine.

Amino acid contribution to protein solubility: Asp, Glu, and Ser contribute more favorably than the other hydrophilic amino acids in RNase Sa

PubMed Central

Trevino, Saul R.; Scholtz, J. Martin; Pace, C. Nick

2009-01-01

SUMMARY Poor protein solubility is a common problem in high resolution structural studies, formulation of protein pharmaceuticals, and biochemical characterization of proteins. One popular strategy to improve protein solubility is to use site-directed mutagenesis to make hydrophobic to hydrophilic mutations on the protein surface. However, a systematic investigation of the relative contributions of all twenty amino acids to protein solubility has not been done. Here, twenty variants at the completely solvent-exposed position 76 of Ribonuclease (RNase) Sa are made to compare the contributions of each amino acid. Stability measurements were also made for these variants, which occur at the i+1 position of a type II β-turn. Solubility measurements in ammonium sulfate solutions were made at high positive net charge, low net charge, and high negative net charge. Surprisingly, there was a wide range of contributions to protein solubility even among the hydrophilic amino acids. The results suggest that aspartic acid, glutamic acid, and serine contribute significantly more favorably than the other hydrophilic amino acids especially at high net charge. Therefore, to increase protein solubility, asparagine, glutamine, or threonine should be replaced with aspartic acid, glutamic acid or serine. PMID:17174328

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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

Solubility of HCL in sulfuric acid at stratospheric temperatures

NASA Technical Reports Server (NTRS)

Williams, Leah R.; Golden, David M.

1993-01-01

The solubility of HCl in sulfuric acid was measured using a Knudsen cell technique. Effective Henry's law constants are reported for sulfuric acid concentrations between 50 and 60 weight percent and for temperatures between 220 and 230 K. The measured values indicate that very little HCl will be dissolved in the stratospheric sulfate aerosol particles.

GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R. A.

2012-03-12

HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into themore » H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of

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

PubMed

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.

Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1: preparation, stability and dissolution enhancement.

PubMed

Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka; Strachan, Clare; Rades, Thomas

2013-11-01

Poor aqueous solubility of an active pharmaceutical ingredient (API) is one of the most pressing problems in pharmaceutical research and development because up to 90% of new API candidates under development are poorly water soluble. These drugs usually have a low and variable oral bioavailability, and therefore an unsatisfactory therapeutic effect. One of the most promising approaches to increase dissolution rate and solubility of these drugs is the conversion of a crystalline form of the drug into its respective amorphous form, usually by incorporation into hydrophilic polymers, forming glass solutions. However, this strategy only led to a small number of marketed products usually because of inadequate physical stability of the drug (crystallization). In this study, we investigated a fundamentally different approach to stabilize the amorphous form of drugs, namely the use of amino acids as small 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 and the amino acids arginine, phenylalanine, tryptophan and tyrosine were prepared by vibrational ball milling. Solid-state characterization with X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed that the various blends could be prepared as homogeneous, single phase co-amorphous formulations indicated by the appearance of an amorphous halo in the XRPD diffractograms and a single glass transition temperature (Tg) in the DSC measurements. In addition, the Tgs of the co-amorphous mixtures were significantly increased over those of the individual drugs. The drugs remained chemically stable during the milling process and the co-amorphous formulations were generally physically stable over at least 6 months at 40 °C under dry conditions. The

Design of biodegradable nanoparticles: a novel approach to encapsulating poorly soluble phytochemical ellagic acid

NASA Astrophysics Data System (ADS)

Bala, I.; Bhardwaj, V.; Hariharan, S.; Sitterberg, J.; Bakowsky, U.; Kumar, M. N. V. Ravi

2005-12-01

Nanosizing of poorly water soluble drugs or incorporating them into nanoparticles to increase their solubility and thereby the bioavailability has become a favoured approach today. This work describes a novel method for encapsulating poorly water soluble phytochemical ellagic acid that is also sparingly soluble/insoluble in routine solvents used to prepare nanoparticles.

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

PubMed

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.

Water solubility enhancement of some organic pollutants and pesticides by dissolved humic and fulvic acids

USGS Publications Warehouse

Chiou, C.T.; Malcolm, R.L.; Brinton, T.I.; Kile, D.E.

1986-01-01

Water solubility enhancements by dissolved humic and fulvic acids from soil and aquatic origins and by synthetic organic polymers have been determined for selected organic pollutants and pesticides (p,p???-DDT, 2,4,5,2???,5???-PCB, 2,4,4???-PCB, 1,2,3-trichlorobenzene, and lindane). Significant solubility enhancements of relatively water-insoluble solutes by dissolved organic matter (DOM) of soil and aquatic origins may be described in terms of a partition-like interaction of the the solutes with the microscopic organic environment of the high-molecular-weight DOM species; the apparent solute solubilities increase linearly with DOM concentration and show no competitive effect between solutes. With a given DOM sample, the solute partition coefficient (Kdom) increases with a decrease of solute solubility (Sw) or with an increase of the solute's octanol-water partition coefficient (Kow). The Kdom values of solutes with soil-derived humic acid are approximately 4 times greater than with soil fulvic acid and 5-7 times greater than with aquatic humic and fulvic acids. The effectiveness of DOM in enhancing solute solubility appears to be largely controlled by the DOM molecular size and polarity. The relative inability of high-molecular-weight poly(acrylic acids) to enhance solute solubility is attributed to their high polarities and extended chain structures that do not permit the formation of a sizable intramolecular nonpolar environment.

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

PubMed Central

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

2016-01-01

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. PMID:27042997

Measurement and correlation of the solubility of gossypol acetic acid and gossypol acetic acid of optical activity in different solvents

NASA Astrophysics Data System (ADS)

Zhang, B.; Tang, H.; Liu, X. Y.; Zhai, X.; Yao, X. C.

2018-01-01

The equilibrium method was used to measure the solubility of gossypol acetic acid and gossypol acetic acid of optical activity in isopropyl alcohol, ethanol, acetic acid and ethyl acetate at temperature from 288.15 to 315.15. The Empirical equation and the Apelblat equation model were adopted to correlate the experimental data. For gossypol acetic acid, the root-mean-square deviations (RMSD) were observed in the range of 0.023-4.979 and 0.0112-0.614 for the Empirical equation and the Apelblat equation, respectively. For gossypol acetic acid of optical activity, the RMSD were observed in the range of 0.021-2.211 and 0.021-2.243 for the Empirical equation and the Apelblat equation, individually. And the maximum relative average deviation was 7.5%. Both equations offered an accurate mathematical expression of the experimental results. The calculated solubility showed a good relationship with the experimental solubility for most of solvents. This study provided valuable datas not only for optimizing the process of purification of gossypol acetic acid of optical activity in industry but also for further theoretical studies.

Solubility calculations of branched and linear amino acids using lattice cluster theory

NASA Astrophysics Data System (ADS)

Fischlschweiger, Michael; Enders, Sabine; Zeiner, Tim

2014-09-01

In this work, the activity coefficients and the solubility of amino acids in water were calculated using the lattice cluster theory (LCT) combined with the extended chemical association lattice model allowing self-association as well as cross-association. This permits the study of the influence of the amino acids structure on the thermodynamic properties for the first time. By the used model, the activity coefficient and solubilities of the investigated fourteen amino acids (glycine, alanine, γ-aminobutyric acid, dl-valine, dl-threonine, dl-methionine, l-leucine, l-glutamic acid, l-proline, hydroxyproline, histidine, l-arginine, α-amino valeric acid) could be described in good accordance with experimental data. In the case of different α-amino acids, but different hydrocarbon chains, the same interaction energy parameter can be used within the LCT. All studied amino acids could be modelled using the same parameter for the description of the amino acid association properties. The formed cross-associates contain more amino acids than expressed by the overall mole fraction of the solution. Moreover, the composition of the cross-associates depends on temperature, where the amount of amino acids increases with increasing temperature.

Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.A.

1998-10-02

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 approximately 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 the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBPmore » solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated

Solubility and precipitation of nicotinic acid in supercritical carbon dioxide.

PubMed

Rehman, M; Shekunov, B Y; York, P; Colthorpe, P

2001-10-01

Solubilities of a model compound (nicotinic acid) in pure supercritical carbon dioxide (SC-CO(2)) and SC-CO(2) modified with methanol have been measured in the pressure range of 80-200 bar and between temperatures of 35 and 90 degrees C. On-line ultraviolet detection enabled a simple and relatively fast measurement of very low levels of solubility (10(-7) mol fraction) with good accuracy in pure and modified SC-CO(2). The solute solubility in both pure SC-CO(2) and SC-CO(2) modified with methanol increased with pressure at all investigated temperatures. A retrograde solubility behavior was observed in that, at pressures below 120 bar, a solubility decrease on temperature increase occurred. Solubility data were used to calculate supersaturation values and to define optimum operating conditions to obtain crystalline particles 1-5 microm in diameter using the solution-enhanced dispersion by supercritical fluids (SEDS) process, thereby demonstrating the feasibility of a one-step production process for particulate pharmaceuticals suitable for respiratory drug delivery. Copyright 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1570-1582, 2001

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

PubMed

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

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

PubMed Central

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.

PubMed

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.

PubMed

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.

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

PubMed

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).

PubMed

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.

Different small, acid-soluble proteins of the alpha/beta type have interchangeable roles in the heat and UV radiation resistance of Bacillus subtilis spores.

PubMed Central

Mason, J M; Setlow, P

1987-01-01

Spores of Bacillus subtilis strains which carry deletion mutations in one gene (sspA) or two genes (sspA and sspB) which code for major alpha/beta-type small, acid-soluble spore proteins (SASP) are known to be much more sensitive to heat and UV radiation than wild-type spores. This heat- and UV-sensitive phenotype was cured completely or in part by introduction into these mutant strains of one or more copies of the sspA or sspB genes themselves; multiple copies of the B. subtilis sspD gene, which codes for a minor alpha/beta-type SASP; or multiple copies of the SASP-C gene, which codes for a major alpha/beta-type SASP of Bacillus megaterium. These findings suggest that alpha/beta-type SASP play interchangeable roles in the heat and UV radiation resistance of bacterial spores. Images PMID:3112127

Production of low-molecular weight soluble yeast β-glucan by an acid degradation method.

PubMed

Ishimoto, Yuina; Ishibashi, Ken-Ichi; Yamanaka, Daisuke; Adachi, Yoshiyuki; Kanzaki, Ken; Iwakura, Yoichiro; Ohno, Naohito

2018-02-01

β-glucan is widely distributed in nature as water soluble and insoluble forms. Both forms of β-glucan are utilized in several fields, especially for functional foods. Yeast β-glucan is a medically important insoluble particle. Solubilization of yeast β-glucan may be valuable for improving functional foods and in medicinal industries. In the present study, we applied an acid degradation method to solubilize yeast β-glucan and found that β-glucan was effectively solubilized to low-molecular weight β-glucans by 45% sulfuric acid treatment at 20°C. The acid-degraded soluble yeast β-glucan (ad-sBBG) was further fractionated into a higher-molecular weight fraction (ad-sBBG-high) and a lower-molecular weight fraction (ad-sBBG-low). Since ad-sBBG-high contained mannan, while ad-sBBG-low contained it only scarcely, it was possible to prepare low-molecular weight soluble β-glucan with higher purity. In addition, ad-sBBG-low bound to dectin-1, which is an innate immunity receptor of β-glucan, and showed antagonistic activity against reactive oxygen production and cytokine synthesis by macrophages. Thus, this acid degradation method is an important procedure for generating immune-modulating, low-molecular weight, soluble yeast β-glucan. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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.

Solubility relationships of aluminum and iron minerals associated with acid mine drainage

NASA Astrophysics Data System (ADS)

Sullivan, Patrick J.; Yelton, Jennifer L.; Reddy, K. J.

1988-06-01

The ability to properly manage the oxidation of pyritic minerals and associated acid mine drainage is dependent upon understanding the chemistry of the disposal environment. One accepted disposal method is placing pyritic-containing materials in the groundwater environment. The objective of this study was to examine solubility relationships of Al and Fe minerals associated with pyritic waste disposed in a low leaching aerobic saturated environment. Two eastern oil shales were used in this oxidizing equilibration study, a New Albany Shale (unweathered, 4.6 percent pyrite), and a Chattanooga Shale (weathered, 1.5 percent pyrite). Oil shale samples were equilibrated with distilled-deionized water from 1 to 180 d with a 1∶1 solid-to-solution ratio. The suspensions were filtered and the clear filtrates were analyzed for total cations and anions. Ion activities were calculated from total concentrations. Below pH 6.0, depending upon SO{4/2-} activity, Al3+ solubility was controlled by AlOHSO4 (solid phase) for both shales. Initially, Al3+ solubility for the New Albany Shale showed equilibrium with amorphous Al(OH)3. The pH decreased with time, and Al3+ solubility approached equilibrium with AlOHSO4(s). Below pH 6.0, Fe3+ solubility appeared to be regulated by a basic iron sulfate solid phase with the stoichiometric composition of FeOHSO4(s). The results of this study indicate that below pH 6.0, Al3+ solubilities, are limited by basic Al and Fe sulfate solid phases (AlOHSO4(s) and FeHSO4(s)). The results from this study further indicate that the acidity in oil shale waters is produced from the hydrolysis of Al3+ and Fe3+ activities in solution. These results indicate a fundamental change in the stoichiometric equations used to predict acidity from iron sulfide oxidation. The results of this study also indicate that water quality predictions associated with acid mine drainage can be based on fundamental thermodynamic relationships. As a result, waste management decisions

Click strategy using disodium salts of amino acids improves the water solubility of plinabulin and KPU-300.

PubMed

Yakushiji, Fumika; Muguruma, Kyohei; Hayashi, Yoshiki; Shirasaka, Takuya; Kawamata, Ryosuke; Tanaka, Hironari; Yoshiwaka, Yushi; Taguchi, Akihiro; Takayama, Kentaro; Hayashi, Yoshio

2017-07-15

Plinabulin and KPU-300 are promising anti-microtubule agents; however, the low water solubility of these compounds (<0.1µg/mL) has limited their pharmaceutical advantages. Here, we developed five water-soluble derivatives of plinabulin and KPU-300 with a click strategy using disodium salts of amino acids. The mother skeleton, diketopiperazine (DKP), was transformed into a monolactim-type alkyne and a copper-catalyzed alkyne azide cycloaddition (CuAAC) combined azides that was derived from amino acids as a water-solubilizing moiety. The conversion of carboxyl groups into disodium salts greatly improved the water solubility by 0.8 million times compared to the solubility of the parent molecules. In addition, the α-amino acid side chains of the water-solubilizing moieties affected both the water solubility and the half-lives of the compounds during enzymatic hydrolysis. Our effort to develop a variety of water-soluble derivatives using the click strategy has revealed that the replaceable water-solubilizing moieties can alter molecular solubility and stability under enzymatic hydrolysis. With this flexibility, we are approaching to the in vivo study using water-soluble derivative. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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.

Quantitative extraction and concentration of synthetic water-soluble acid dyes from aqueous media using a quinine-chloroform solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, F.; Ozawa, N.; Hanai, J.

Twenty-one water-soluble acid dyes, including eleven azo, five triphenylmethane four xanthene, one naphthol derivatives, used at practical concentrations for food coloration, were quantitatively extracted from water and various carbonated beverages into a 0.1 M quinine-chloroform solution in the presence of 0.5 M boric acid by brief shaking. Quantitative extraction of these dyes was also accomplished by the 0.1 M quinine-chloroform solution made conveniently from chloroform, quinine hydrochloride, and sodium hydroxide added successively to water or beverages containing boric acid. Quinine acted as a countercation on the dyes having sulfonic and/or carboxylic acid group(s) to form chloroform-soluble ion-pair complexes. The diacidicmore » base alkaloid interacted with each acid group of mono-, di-, tri-, and tetrasulfonic acid dyes approximately in the ratio 0.8-0.9 to 1. The dyes in the chloroform solution were quantitatively concentrated into a small volume of sodium hydroxide solution also by brief shaking. The convenient quinine-chloroform method was applicable to the quantitative extraction of a mixture of 12 dyes from carbonated beverages, which are all currently used for food coloration. A high-pressure liquid chromatographic method is also presented for the systematic separation and determination of these 12 dyes following their concentration into the aqueous alkaline solution. The chromatogram was monitored by double-wavelength absorptiometry in the visible and ultraviolet ray regions.« less

New water-soluble metal working fluids additives from phosphonic acid derivatives for aluminum alloy materials.

PubMed

Kohara, Ichitaro; Tomoda, Hideyuki; Watanabe, Shoji

2007-01-01

Water-soluble metal working fluids are used for processing of aluminum alloy materials. This short paper describes properties of new additives for water-soluble cutting fluids for aluminum alloy materials. Some alkyldiphosphonic acids were prepared with known method. Amine salts of these phosphonic acids showed anti-corrosion property for aluminum alloy materials. However, they have no hard water tolerance. Monoesters of octylphosphonic acid were prepared by the reaction of octylphosphonic acid dichloride with various alcohols in the presence of triethylamine. Amine salts of monoester of octylphosphonic acid with diethyleneglycol monomethyl ether, ethyleneglycol monomethyl ether and triethyleneglycol monomethyl ether showed both of a good anti-corrosion property for aluminum alloy materials and hard water tolerance.

Incorporation of titanate nanosheets to enhance mechanical properties of water-soluble polyamic acid

NASA Astrophysics Data System (ADS)

Harito, C.; Bavykin, Dmitry V.; Walsh, Frank C.

2017-07-01

Pyromeliticdianhydride (PMDA) and 4’,4’-oxydianiline (ODA) were used as monomers of polyimide. To synthesise a water soluble polyimide precursor (polyamic acid salt), triethylamine (TEA) was added to polyamic acid with a TEA/COOH mole ratio of 1:1. Titanate nanosheets were synthesised by solid-state reaction, ion-exchanged with acid, and exfoliated by TEA. Exfoliated titanate nanosheets were mixed with water soluble polyamic acid salt as reinforcing filler. Drop casting was deployed to synthesise polyamic acid/titanate nanosheet nanocomposite films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the morphology and dispersion of nanosheets in the colloidal dispersion and the solid film composite. Modulus and hardness of nanocomposites was provided by nanoindentation. Hardness increased by 90% with addition of 2% TiNS while modulus increased by 103% compared to pure polymer. This behaviour agrees well with Halpin-Tsai theoretical predictions up to 2 wt% filler loading; agglomeration occurs at higher concentrations.

Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.

PubMed

Uchimiya, Minori; Bannon, Desmond I

2013-08-14

Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 °C (CH350) and 700 °C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.

Production of a water-soluble fertilizer containing amino acids by solid-state fermentation of soybean meal and evaluation of its efficacy on the rapeseed growth.

PubMed

Wang, Jianlei; Liu, Zhemin; Wang, Yue; Cheng, Wen; Mou, Haijin

2014-10-10

Soybean meal is a by-product of soybean oil extraction and contains approximately 44% protein. We performed solid-state fermentation by using Bacillus subtilis strain N-2 to produce a water-soluble fertilizer containing amino acids. Strain N-2 produced a high yield of protease, which transformed the proteins in soybean meal into peptide and free amino acids that were dissolved in the fermentation products. Based on the Plackett-Burman design, the initial pH of the fermentation substrate, number of days of fermentation, and the ratio of liquid to soybean meal exhibited significant effects on the recovery of proteins in the resulting water-soluble solution. According to the predicted results of the central composite design, the highest recovery of soluble proteins (99.072%) was achieved at the optimum conditions. Under these conditions, the resulting solution contained 50.42% small peptides and 7.9% poly-γ-glutamic acid (γ-PGA). The water-soluble fertilizer robustly increased the activity of the rapeseed root system, chlorophyll content, leaf area, shoot dry weight, root length, and root weight at a concentration of 0.25% (w/v). This methodology offers a value-added use of soybean meal. Copyright © 2014 Elsevier B.V. All rights reserved.

Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

PubMed

Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

2012-11-02

To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids.

7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in...

7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in...

Acid-base properties of water-soluble organic matter of forest soils, studied by the pK-spectroscopy method.

PubMed

Shamrikova, E V; Ryazanov, M A; Vanchikova, E V

2006-11-01

Using the potentiometric titration and pK spectroscopy method, acid-base properties of water-soluble organic matter of forest soils have been studied. Five acidic classes composed of different substances with pK(a) values around 3.6; 4.8; 6.7; 8.7 and 9.7 have been identified. Testing the properties of soluble soil fraction, it is to be taken into account that when it is isolated from non-soluble soil matter, some water-soluble substances remain in soil and do not pass into the solution. Most firmly adsorbed in soil are water-soluble components with pK(a) 9.6-9.8.

Comparison of free amino acids, antioxidants, soluble phenolic acids, cytotoxicity and immunomodulation of fermented mung bean and soybean.

PubMed

Ali, Norlaily Mohd; Yeap, Swee-Keong; Yusof, Hamidah Mohd; Beh, Boon-Kee; Ho, Wan-Yong; Koh, Soo-Peng; Abdullah, Mohd Puad; Alitheen, Noorjahan Banu; Long, Kamariah

2016-03-30

Mung bean and soybean have been individually reported previously to have antioxidant, cytotoxic and immunomodulatory effects, while fermentation is a well-known process to enhance the bioactive compounds that contribute to higher antioxidant, cytotoxic and immunomodulation effects. In this study, the free amino acids profile, soluble phenolic acids content, antioxidants, cytotoxic and immunomodulatory effects of fermented and non-fermented mung bean and soybean were compared. Fermented mung bean was recorded to have the highest level of free amino acids, soluble phenolic acids (especially protocatechuic acid) and antioxidant activities among all the tested products. Both fermented mung bean and soybean possessed cytotoxicity activities against breast cancer MCF-7 cells by arresting the G0/G1 phase followed by apoptosis. Moreover, fermented mung bean and soybean also induced splenocyte proliferation and enhanced the levels of serum interleukin-2 and interferon-γ. Augmented amounts of free amino acids and phenolic acids content after fermentation enhanced the antioxidants, cytotoxicity and immunomodulation effects of mung bean and soybean. More specifically, fermented mung bean showed the best effects among all the tested products. This study revealed the potential of fermented mung bean and soybean as functional foods for maintenance of good health. © 2015 Society of Chemical Industry.

Solubility of HOBr in Acidic Solution and Implications for Liberation of Halogens Via Aerosol Processing

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Michelsen, R. R.; Rammer, T. A.; Ashbourn, S. F. M.

2004-01-01

Halogen species are known to catalytically destroy ozone in several regions of the atmosphere. In addition to direct catalytic losses, bromine compounds can indirectly enhance ozone loss through coupling to other radical families. Hypobromous acid (HOBr) is a key species in the linkage of BrOx to ClOx and HOx. The aqueous- phase coupling reaction HOBr + HCI (right arrow) BrCl + H2O may provide a pathway for chlorine activation on sulfate aerosols at temperatures warmer than those required for polar stratospheric cloud formation. We have measured t h e solubility of HOBr in 45 - 70 wt% sulfuric acid solutions. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, H* = 10(exp 4) - 10(exp 7) mol dm(exp -3) atm(exp -1). The expected inverse dependence of H* on temperature was observed, but only a weak dependence on acidity was found. The solubility of HOBr is comparable to that of HBr, indicating that equilibrium concentrations of HOBr could equal or exceed those of HBr in upper tropospheric and lower stratospheric aerosols. Despite the high solubility of HOBr, aerosol volumes are not large enough to sequester a significant fraction of inorganic bromine from the gas phase. Our measurements of HOBr uptake in aqueous sulfuric acid in the presence of other brominated gases show the evolution of gaseous products including Br2O and Br2.

7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Maximum anhydrous citric acid permissible for... Common Sweet Oranges (citrus Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for... following Table II together with the minimum ratio of total soluble solids to anhydrous citric acid: Table...

7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Maximum anhydrous citric acid permissible for... Common Sweet Oranges (citrus Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for... following Table II together with the minimum ratio of total soluble solids to anhydrous citric acid: Table...

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua

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 formationmore » and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)« less

Use of amino acids as counterions improves the solubility of the BCS II model drug, indomethacin.

PubMed

ElShaer, Amr; Khan, Sheraz; Perumal, Dhaya; Hanson, Peter; Mohammed, Afzal R

2011-07-01

The number of new chemical entities (NCE) is increasing every day after the introduction of combinatorial chemistry and high throughput screening to the drug discovery cycle. One third of these new compounds have aqueous solubility less than 20µg/mL [1]. Therefore, a great deal of interest has been forwarded to the salt formation technique to overcome solubility limitations. This study aims to improve the drug solubility of a Biopharmaceutical Classification System class II (BCS II) model drug (Indomethacin; IND) using basic amino acids (L-arginine, L-lysine and L-histidine) as counterions. Three new salts were prepared using freeze drying method and characterised by FT-IR spectroscopy, proton nuclear magnetic resonance ((1)HNMR), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). The effect of pH on IND solubility was also investigated using pH-solubility profile. Both arginine and lysine formed novel salts with IND, while histidine failed to dissociate the free acid and in turn no salt was formed. Arginine and lysine increased IND solubility by 10,000 and 2296 fold, respectively. An increase in dissolution rate was also observed for the novel salts. Since these new salts have improved IND solubility to that similar to BCS class I drugs, IND salts could be considered for possible waivers of bioequivalence.

Effectiveness of oil-soluble corrosion inhibitors during corrosion-mechanical breakdown in acid and neutral media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kardash, N.V.; Egorov, V.V.; Forman, A.Y.

1986-11-01

The purpose of the present study is to ascertain the effectiveness of familiar additives and oil-soluble inhibitors under conditions of acid corrosion in comparison with their rapid action and waterreplacement efficiency, and the capacity to inhibit an electrolyte that forms in the oils, to protect against electrochemical corrosion, especially from pitting, and to reduce the mechanical-corrosion forms of wear. Characteristics of several oil-soluble corrosion inhibitors and the effectiveness of the oil-soluble inhibitors are shown. The additives M, ALOP, and MONIKA are most effective under fretting-corrosion conditions. It is shown that only the combined additives and compositions that provide for metalmore » protection in both acid and neutral media are sufficiently effective in preventing corrosion cracking, fatigue, corrosion fatigue and corrosion fretting.« less

Ultrasound assisted cocrystallization from solution (USSC) containing a non-congruently soluble cocrystal component pair: Caffeine/maleic acid.

PubMed

Aher, Suyog; Dhumal, Ravindra; Mahadik, Kakasaheb; Paradkar, Anant; York, Peter

2010-12-23

Ultrasound assisted solution cocrystallization (USSC) has been studied using a non-congruently soluble pair of caffeine and maleic acid in methanol. USSC was compared with solvent cooling and slurry sonication using different molar ratios of caffeine:maleic acid (1:0.5, 1:1, 1:2, 1:3 and 1:3.5) in solution/slurry. Products were characterized by PXRD and Raman spectroscopy techniques. In USSC trials, the content of cocrystal in the product was observed to increase with increase in amount of maleic acid in solution. Only USSC offered pure caffeine/maleic acid 2:1 cocrystal product when caffeine:maleic acid; 1:3.5 molar ratio was taken in solution. Caffeine/maleic acid 1:1 cocrystal and maleic acid were not obtained in neither of the techniques. Products of solvent cooling and slurry sonication experiments were mixtures of caffeine and caffeine/maleic acid 2:1 cocrystal in varying amounts. In USSC, ultrasound application must have attained simultaneous supersaturation of cocrystal components in solution due to altered supersaturation conditions resulting in cocrystal formation. For this simultaneous attainment of supersaturation, molar ratio of cocrystal components in solution was identified as an important parameter while designing experiments for a non-congruently soluble pair having large solubility difference. Copyright © 2010 Elsevier B.V. All rights reserved.

Enhancement of carvedilol solubility by solid dispersion technique using cyclodextrins, water soluble polymers and hydroxyl acid.

PubMed

Yuvaraja, K; Khanam, Jasmina

2014-08-05

Aim of the present work is to enhance aqueous solubility of carvedilol (CV) by solid dispersion technique using wide variety of carriers such as: β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD), tartaric acid (TA), polyvinyl pyrrolidone K-30 (PVP K-30) and poloxamer-407 (PLX-407). Various products of 'CV-solid dispersion' had been studied extensively in various pH conditions to check enhancement of solubility and dissolution characteristics of carvedilol. Any physical change upon interaction between CV and carriers was confirmed by instrumental analysis: XRD, DSC, FTIR and SEM. Negative change of Gibb's free energy and complexation constants (Kc, 75-240M(-1), for cyclodextrins and 1111-20,365M(-1), for PVP K-30 and PLX-407) were the evidence of stable nature of the binding between CV and carriers. 'Solubility enhancement factor' of ionized-CV was found high enough (340 times) with HPβCD in presence of TA. TA increases the binding efficiency of cyclodextrin and changing the pH of microenvironment in dissolution medium. In addition, ionization process was used to increase the apparent intrinsic solubility of drug. In vitro, dissolution time of CV was remarkably reduced in the solid dispersion system compared to that of pure drug. This may be attributed to increased wettability, dispersing ability and transformation of crystalline state of drug to amorphous one. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed

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.

Water-soluble organic carbon, dicarboxylic acids, ketoacids, and α-dicarbonyls in the tropical Indian aerosols

NASA Astrophysics Data System (ADS)

Pavuluri, Chandra Mouli; Kawamura, Kimitaka; Swaminathan, T.

2010-06-01

Tropical aerosol (PM10) samples (n = 49) collected from southeast coast of India were studied for water-soluble dicarboxylic acids (C2-C12), ketocarboxylic acids (C2-C9), and α-dicarbonyls (glyoxal and methylglyoxal), together with analyses of total carbon (TC) and water-soluble organic carbon (WSOC). Their distributions were characterized by a predominance of oxalic acid followed by terephthalic (t-Ph), malonic, and succinic acids. Total concentrations of diacids (227-1030 ng m-3), ketoacids (16-105 ng m-3), and dicarbonyls (4-23 ng m-3) are comparative to those from other Asian megacities such as Tokyo and Hong Kong. t-Ph acid was found as the second most abundant diacid in the Chennai aerosols. This feature has not been reported previously in atmospheric aerosols. t-Ph acid is most likely derived from the field burning of plastics. Water-soluble diacids were found to contribute 0.4%-3% of TC and 4%-11% of WSOC. Based on molecular distributions and backward air mass trajectories, we found that diacids and related compounds in coastal South Indian aerosols are influenced by South Asian and Indian Ocean monsoons. Organic aerosols are also suggested to be significantly transported long distances from North India and the Middle East in early winter and from Southeast Asia in late winter, but some originate from photochemical reactions over the Bay of Bengal. In contrast, the Arabian Sea, Indian Ocean, and South Indian continent are suggested as major source regions in summer. We also found daytime maxima of most diacids, except for C9 and t-Ph acids, which showed nighttime maxima in summer. Emissions from marine and terrestrial plants, combined with land/sea breezes and in situ photochemical oxidation, are suggested especially in summer as an important factor that controls the composition of water-soluble organic aerosols over the southeast coast of India. Regional emissions from anthropogenic sources are also important in megacity Chennai, but their influence is

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

THE SMALL ACID SOLUBLE PROTEINS (SASP α and SASP β) OF BACILLUS WEIHENSTEPHANENSIS AND B. MYCOIDES GROUP 2 ARE THE MOST DISTINCT AMONG THE B. CEREUS GROUP

PubMed Central

Callahan, Courtney; Fox, Karen; Fox, Alvin

2009-01-01

The Bacillus cereus group includes Bacillus anthracis, Bacillus cereus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis. The small acid-soluble spore protein (SASP) β has been previously demonstrated to be among the biomarkers differentiating B. anthracis and B. cereus; SASP β of B. cereus most commonly exhibits one or two amino acid substitutions when compared to B. anthracis. SASP α is conserved in sequence among these two species. Neither SASP α nor β for B. thuringiensis, B. mycoides and B. weihenstephanensis have been previously characterized as taxonomic discriminators. In the current work molecular weight (MW) variation of these SASPs were determined by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) for representative strains of the 5 species within the B. cereus group. The measured MWs also correlate with calculated MWs of translated amino acid sequences generated from whole genome sequencing projects. SASP α and β demonstrated consistent MW among B. cereus, B. thuringiensis, and B. mycoides strains (group 1). However B. mycoides (group 2) and B. weihenstephanensis SASP α and β were quite distinct making them unique among the B. cereus group. Limited sequence changes were observed in SASP α (at most 3 substitutions and 2 deletions) indicating it is a more conserved protein than SASP β (up to 6 substitutions and a deletion). Another even more conserved SASP, SASP α-β type, was described here for the first time. PMID:19616612

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.

PubMed

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.

Solubility of ammonium acid urate nephroliths from bottlenose dolphins (Tursiops truncatus).

PubMed

Argade, Sulabha; Smith, Cynthia R; Shaw, Timothy; Zupkas, Paul; Schmitt, Todd L; Venn-Watson, Stephanie; Sur, Roger L

2013-12-01

Nephrolithiasis has been identified in managed populations of bottlenose dolphins (Tursiops truncatus); most of these nephroliths are composed of 100% ammonium acid urate (AAU). Several therapies are being investigated to treat and prevent nephrolithiasis in dolphins including the alkalization of urine for dissolution of nephroliths. This study evaluates the solubility of AAU nephroliths in a phosphate buffer, pH range 6.0-8.0, and in a carbonate-bicarbonate buffer, pH range 9.0-10.8. AAU nephroliths were obtained from six dolphins and solubility studies were conducted using reverse-phase high performance liquid chromatography with ultraviolet detection at 290 nm. AAU nephroliths were much more soluble in a carbonate-bicarbonate buffer, pH range 9.0-10.8 compared to phosphate buffer pH range 6.0-8.0. In the pH range 6.0-8.0, the solubility was 45% lower in potassium phosphate buffer compared to sodium phosphate buffer. When citrate was used along with phosphate in the same pH range, the solubility was improved by 13%. At pH 7 and pH 8, 150 mM ionic strength buffer was optimum for dissolution. In summary, adjustment of urinary pH alone does not appear to be a useful way to treat AAU stones in bottlenose dolphins. Better understanding of the pathophysiology of AAU nephrolithiasis in dolphins is needed to optimize kidney stone prevention and treatment.

A new small molecule inhibitor of soluble guanylate cyclase

PubMed Central

Mota, Filipa; Gane, Paul; Hampden-Smith, Kathryn; Allerston, Charles K.; Garthwaite, John; Selwood, David L.

2015-01-01

Soluble guanylate cyclase (sGC) is a haem containing enzyme that regulates cardiovascular homeostasis and multiple mechanisms in the central and peripheral nervous system. Commonly used inhibitors of sGC activity act through oxidation of the haem moiety, however they also bind haemoglobin and this limits their bioavailability for in vivo studies. We have discovered a new class of small molecule inhibitors of sGC and have characterised a compound designated D12 (compound 10) which binds to the catalytic domain of the enzyme with a KD of 11 μM in a SPR assay. PMID:26264842

Isolation and characterization of acid-soluble collagen from the scales of marine fishes from Japan and Vietnam.

PubMed

Minh Thuy, Le Thi; Okazaki, Emiko; Osako, Kazufumi

2014-04-15

Acid-soluble collagen (ASC) was successfully extracted from the scales of lizard fish (Saurida spp.) and horse mackerel (Trachurus japonicus) from Japan and Vietnam and grey mullet (Mugil cephalis), flying fish (Cypselurus melanurus) and yellowback seabream (Dentex tumifrons) from Japan. ASC yields were about 0.43-1.5% (on a dry weight basis), depending on the species. The SDS-PAGE profile showed that the ASCs were type I collagens, and consisted of two different α chains, α1 and α2, as well as a β component. ASC of horse mackerel from Vietnam contained a higher imino acid level than that from Japan. ASC denaturation temperature (Td) ranged from 26 to 29 °C, depending on fish species and imino acid content (p<0.01). Maximal solubility of individual collagens was observed at pHs 1-3. Collagen solubility decreased sharply at NaCl concentrations >0.4M, regardless of fish type. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solubility of methanol in low-temperature aqueous sulfuric acid and implications for atmospheric particle composition

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

2001-01-01

Using traditional Knudsen cell techniques, we find well-behaved Henry's law uptake of methanol in aqueous 45 - 70 wt% H2SO4 solutions at temperatures between 197 and 231 K. Solubility of methanol increases with decreasing temperature and increasing acidity, with an effective Henry's law coefficient ranging from 10(exp 5) - 10(exp 8) M/atm. Equilibrium uptake of methanol into sulfuric acid aerosol particles in the upper troposphere and lower stratosphere will not appreciably alter gas-phase concentrations of methanol. The observed room temperature reaction between methanol and sulfuric acid is too slow to provide a sink for gaseous methanol at the temperatures of the upper troposphere and lower stratosphere. It is also too slow to produce sufficient quantities of soluble reaction products to explain the large amount of unidentified organic material seen in particles of the upper troposphere.

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

PubMed

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

Solubility Database

National Institute of Standards and Technology Data Gateway

SRD 106 IUPAC-NIST Solubility Database (Web, free access)   These solubilities are compiled from 18 volumes (Click here for List) of the International Union for Pure and Applied Chemistry(IUPAC)-NIST Solubility Data Series. The database includes liquid-liquid, solid-liquid, and gas-liquid systems. Typical solvents and solutes include water, seawater, heavy water, inorganic compounds, and a variety of organic compounds such as hydrocarbons, halogenated hydrocarbons, alcohols, acids, esters and nitrogen compounds. There are over 67,500 solubility measurements and over 1800 references.

Highly Acidic Ambient Particles, Soluble Metals, and Oxidative Potential: A Link between Sulfate and Aerosol Toxicity.

PubMed

Fang, Ting; Guo, Hongyu; Zeng, Linghan; Verma, Vishal; Nenes, Athanasios; Weber, Rodney J

2017-03-07

Soluble transition metals in particulate matter (PM) can generate reactive oxygen species in vivo by redox cycling, leading to oxidative stress and adverse health effects. Most metals, such as those from roadway traffic, are emitted in an insoluble form, but must be soluble for redox cycling. Here we present the mechanism of metals dissolution by highly acidic sulfate aerosol and the effect on particle oxidative potential (OP) through analysis of size distributions. Size-segregated ambient PM were collected from a road-side and representative urban site in Atlanta, GA. Elemental and organic carbon, ions, total and water-soluble metals, and water-soluble OP were measured. Particle pH was determined with a thermodynamic model using measured ionic species. Sulfate was spatially uniform and found mainly in the fine mode, whereas total metals and mineral dust cations were highest at the road-side site and in the coarse mode, resulting in a fine mode pH < 2 and near neutral coarse mode. Soluble metals and OP peaked at the intersection of these modes demonstrating that sulfate plays a key role in producing highly acidic fine aerosols capable of dissolving primary transition metals that contribute to aerosol OP. Sulfate-driven metals dissolution may account for sulfate-health associations reported in past studies.

Spectrophotometric determination of uric acid and some redeterminations of its solubility

USGS Publications Warehouse

Norton, D.R.; Plunkett, M.A.; Richards, F.A.

1954-01-01

The present study was initiated in order to develop a rapid and accurate method for the determination of uric acid in fresh, brackish, and sea water. It was found that the spectrophotometric determination of uric acid based upon its reaction with arsenophosphotungstic acid reagent in the presence of cyanide ion meets this objective. The absorbancy of the blue complex was measured at 890 m??. Slight variations from Beer's law were generally found. The results show the effects of pH, reaction time, concentration of reagents, and temperature upon color development and precipitate formation. Disodium dihydrogen ethylenediamine tetraacetate (Versene) was used as a buffering and complexirig agent. The results are significant in that they give the absorption spectrum of the blue complex and the effects of variables upon its absorbancy. Studies were made with the method to determine the stability of reagents and standard solutions and to determine the rate of bacterial decomposition of uric acid. Measurements of the solubility of uric acid are reported.

Self-assembling nucleic acid delivery vehicles via linear, water-soluble, cyclodextrin-containing polymers.

PubMed

Davis, M E; Pun, S H; Bellocq, N C; Reineke, T M; Popielarski, S R; Mishra, S; Heidel, J D

2004-01-01

Non-viral (synthetic) nucleic acid delivery systems have the potential to provide for the practical application of nucleic acid-based therapeutics. We have designed and prepared a tunable, non-viral nucleic acid delivery system that self-assembles with nucleic acids and centers around a new class of polymeric materials; namely, linear, water-soluble cyclodextrin-containing polymers. The relationships between polymer structure and gene delivery are illustrated, and the roles of the cyclodextrin moieties for minimizing toxicity and forming inclusion complexes in the self-assembly processes are highlighted. This vehicle is the first example of a polymer-based gene delivery system formed entirely by self-assembly.

Meta-analysis of oral water-soluble contrast agent in the management of adhesive small bowel obstruction.

PubMed

Abbas, S M; Bissett, I P; Parry, B R

2007-04-01

Adhesions are the leading cause of small bowel obstruction. Identification of patients who require surgery is difficult. This review analyses the role of Gastrografin as a diagnostic and therapeutic agent in the management of adhesive small bowel obstruction. A systematic search of Medline, Embase and Cochrane databases was performed to identify studies of the use of Gastrografin in adhesive small bowel obstruction. Studies that addressed the diagnostic role of water-soluble contrast agent were appraised, and data presented as sensitivity, specificity, and positive and negative likelihood ratios. Results were pooled and a summary receiver-operator characteristic (ROC) curve was constructed. A meta-analysis of the data from six therapeutic studies was performed using the Mantel-Haenszel test and both fixed- and random-effect models. The appearance of water-soluble contrast agent in the colon on an abdominal radiograph within 24 h of its administration predicted resolution of obstruction with a pooled sensitivity of 97 per cent and specificity of 96 per cent. The area under the summary ROC curve was 0.98. Water-soluble contrast agent did not reduce the need for surgical intervention (odds ratio 0.81, P = 0.300), but it did reduce the length of hospital stay for patients who did not require surgery compared with placebo (weighted mean difference--1.84 days; P < 0.001). Published data strongly support the use of water-soluble contrast medium as a predictive test for non-operative resolution of adhesive small bowel obstruction. Although Gastrografin does not reduce the need for operation, it appears to shorten the hospital stay for those who do not require surgery.

A soluble acid invertase is directed to the vacuole by a signal anchor mechanism.

PubMed

Rae, Anne L; Casu, Rosanne E; Perroux, Jai M; Jackson, Mark A; Grof, Christopher P L

2011-06-15

Enzyme activities in the vacuole have an important impact on the net concentration of sucrose. In sugarcane (Saccharum hybrid), immunolabelling demonstrated that a soluble acid invertase (β-fructofuranosidase; EC 3.2.1.26) is present in the vacuole of storage parenchyma cells during sucrose accumulation. Examination of sequences from sugarcane, barley and rice showed that the N-terminus of the invertase sequence contains a signal anchor and a tyrosine motif, characteristic of single-pass membrane proteins destined for lysosomal compartments. The N-terminal peptide from the barley invertase was shown to be capable of directing the green fluorescent protein to the vacuole in sugarcane cells. The results suggest that soluble acid invertase is sorted to the vacuole in a membrane-bound form. Copyright © 2010 Elsevier GmbH. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

A Water-Soluble, Two-Photon Probe for Imaging Endogenous Hypochlorous Acid in Live Tissue.

PubMed

Xing, Panfei; Feng, Yanxian; Niu, Yiming; Li, Qiu; Zhang, Zhe; Dong, Lei; Wang, Chunming

2018-04-17

Detection of hypochlorous acid (HClO) in the living system may help to uncover its essential biological functions. However, current imaging agents suffer from poor water solubility that limit their live-tissue applications. Here, a water-soluble probe (NNH) is devised through innovative hydrazone modification of 1,8-naphthalimide at 3' position. NNH was successfully applied to tracking endogenous HClO in both cultured macrophages and a liver injury model in mice. NNH demonstrated remarkably increased water solubility and multiple desirable features including two-photon absorbance, anti-bleaching capability, rapid cellular uptake, and low cytotoxicity. NNH is the first hydrazone-based probe for real-time imaging of HClO in live tissue. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of Gut Microbiota-Mediated Bile Acid Metabolism on the Solubilization Capacity of Bile Salt Micelles and Drug Solubility.

PubMed

Enright, Elaine F; Joyce, Susan A; Gahan, Cormac G M; Griffin, Brendan T

2017-04-03

In recent years, the gut microbiome has gained increasing appreciation as a determinant of the health status of the human host. Bile salts that are secreted into the intestine may be biotransformed by enzymes produced by the gut bacteria. To date, bile acid research at the host-microbe interface has primarily been directed toward effects on host metabolism. The aim of this work was to investigate the effect of changes in gut microbial bile acid metabolism on the solubilization capacity of bile salt micelles and consequently intraluminal drug solubility. First, the impact of bile acid metabolism, mediated in vivo by the microbial enzymes bile salt hydrolase (BSH) and 7α-dehydroxylase, on drug solubility was assessed by comparing the solubilization capacity of (a) conjugated vs deconjugated and (b) primary vs secondary bile salts. A series of poorly water-soluble drugs (PWSDs) were selected as model solutes on the basis of an increased tendency to associate with bile micelles. Subsequently, PWSD solubility and dissolution was evaluated in conventional biorelevant simulated intestinal fluid containing host-derived bile acids, as well as in media modified to contain microbial bile acid metabolites. The findings suggest that deconjugation of the bile acid steroidal core, as dictated by BSH activity, influences micellar solubilization capacity for some PWSDs; however, these differences appear to be relatively minor. In contrast, the extent of bile acid hydroxylation, regulated by microbial 7α-dehydroxylase, was found to significantly affect the solubilization capacity of bile salt micelles for all nine drugs studied (p < 0.05). Subsequent investigations in biorelevant media containing either the trihydroxy bile salt sodium taurocholate (TCA) or the dihydroxy bile salt sodium taurodeoxycholate (TDCA) revealed altered drug solubility and dissolution. Observed differences in biorelevant media appeared to be both drug- and amphiphile (bile salt/lecithin) concentration

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

PubMed

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

Dissolution-modulating mechanism of pH modifiers in solid dispersion containing weakly acidic or basic drugs with poor water solubility.

PubMed

Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Lee, Kyoung-Ho; Kim, Dong-Jin; Lee, Beom-Jin

2010-05-01

Although the solid dispersion method has been known to increase the dissolution rate of poorly water-soluble drugs by dispersing them in hydrophilic carriers, one obstacle of the solid dispersion method is its limited solubilization capacity, especially for pH-dependent soluble drugs. pH-modified solid dispersion, in which pH modifiers are incorporated, may be a useful method for increasing the dissolution rate of weakly acidic or basic drugs. Sufficient research, including the most recent reports, was undertaken in this review. How could the inclusion of the pH the pH modifiers in the solid dispersion system change drug structural behaviors, molecular interactions, microenvironmental pH, and/or release rate of pH modifiers, relating with the enhanced dissolution of weakly acidic or weakly basic drugs with poor water solubility? These questions have been investigated to determine the dissolution-modulating mechanism of pH modifiers in solid dispersion containing weakly acidic or basic drugs. It is believed that step-by-step mechanistic approaches could provide the ultimate solution for solubilizing several poorly water-soluble drugs with pH-dependent solubility from a solid dispersion system, as well as provide ideas for developing future dosage systems.

Toward a Molecular Understanding of Protein Solubility: Increased Negative Surface Charge Correlates with Increased Solubility

PubMed Central

Kramer, Ryan M.; Shende, Varad R.; Motl, Nicole; Pace, C. Nick; Scholtz, J. Martin

2012-01-01

Protein solubility is a problem for many protein chemists, including structural biologists and developers of protein pharmaceuticals. Knowledge about how intrinsic factors influence solubility is limited due to the difficulty of obtaining quantitative solubility measurements. Solubility measurements in buffer alone are difficult to reproduce, because gels or supersaturated solutions often form, making it impossible to determine solubility values for many proteins. Protein precipitants can be used to obtain comparative solubility measurements and, in some cases, estimations of solubility in buffer alone. Protein precipitants fall into three broad classes: salts, long-chain polymers, and organic solvents. Here, we compare the use of representatives from two classes of precipitants, ammonium sulfate and polyethylene glycol 8000, by measuring the solubility of seven proteins. We find that increased negative surface charge correlates strongly with increased protein solubility and may be due to strong binding of water by the acidic amino acids. We also find that the solubility results obtained for the two different precipitants agree closely with each other, suggesting that the two precipitants probe similar properties that are relevant to solubility in buffer alone. PMID:22768947

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

PubMed

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

Water soluble dicarboxylic acids and related compounds in Antarctic aerosols

NASA Astrophysics Data System (ADS)

Kawamura, Kimitaka; SeméRé, Richard; Imai, Yoshie; Fujii, Yoshiyuki; Hayashi, Masahiko

1996-08-01

Antarctic aerosols collected at Syowa Station were studied for water soluble organic compounds by employing a water extraction and dibutyl ester derivatization and using a capillary gas chromatography (GC) and GC/mass spectrometry (GC/MS). Total carbon and nitrogen were also determined. A homologous series of α,ω-dicarboxylic acids (C2-C11), ω-oxocarboxylic acids (C2-C9), and α-dicarbonyls (C2-C3) were detected, as well as pyruvic acid and aromatic (phthalic) diacid. Succinic (C4) or oxalic (C2) acid was found to be the dominant diacid species, followed by azelaic (C9), adipic (C6), or malonic (C3) acid. Concentration range of the total diacids was 5.9-88 ng m-3, with an average of 29 ng m-3. Highest concentrations were observed in the summer sample with a predominance of succinic acid (61.5 ng m-3), which comprised approximately 70% of the total diacids and accounted for 3.5% of total aerosol carbon (1020 ng m-3). The succinic acid (C4) is likely produced by photooxidation of 4-oxocarboxylic acids, which are present in the atmosphere as intermediates of the photooxidation of unsaturated fatty acids. These results indicate that the Antarctic organic aerosols originate from marine-derived lipids and are transformed largely by photochemical oxidations. ω-Oxocarboxylic acids (C2-C9, 0.36-3.0 ng m-3) also showed the highest concentration in the summer sample, again suggesting a secondary production in the atmosphere of the Antarctic and in the Southern Ocean.

Reactions Between Water Soluble Organic Acids and Nitrates in Atmospheric Aerosols: Recycling of Nitric Acid and Formation of Organic Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bingbing; Laskin, Alexander

Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Nitrate as an important inorganic component can be chemically formed in the atmosphere. For instance, formation of sodium nitrate (NaNO3) and calcium nitrate Ca(NO3)2 when nitrogen oxide and nitric acid (HNO3) species react with sea salt and calcite, respectively. Organic acids contribute a significant fraction of photochemically formed secondary organics that can condense on the preexisting nitrate-containing particles. Here, we present a systematic microanalysis study on chemical composition of laboratory generated particles composed of water soluble organic acids and nitrates (i.e.more » NaNO3 and Ca(NO3)2) investigated using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and Fourier transform infrared micro-spectroscopy (micro-FTIR). The results show that water-soluble organic acids can react with nitrates releasing gaseous HNO3 during dehydration process. These reactions are attributed to acid displacement of nitrate with weak organic acids driven by the evaporation of HNO3 into gas phase due to its relatively high volatility. The reactions result in significant nitrate depletion and formation of organic salts in mixed organic acids/nitrate particles that in turn may affect their physical and chemical properties relevant to atmospheric environment and climate. Airborne nitrate concentrations are estimated by thermodynamic calculations corresponding to various nitrate depletions in selected organic acids of atmospheric relevance. The results indicate a potential mechanism of HNO3 recycling, which may further affect concentrations of gas- and aerosol-phase species in the atmosphere and the heterogeneous reaction chemistry between them.« less

LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crapse, K.; Kyser, E.

2011-09-22

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system replaces the current dilute nitric acid strip solution with 0.01 M boric acid. This literature study is performed to determine if there is a potential for boric acid to crystallize in the lines with emphasis on the transfer lines to the Defense Waste Processing Facility. This report focuses on the aqueous phase chemistry of boric acid under conditions relevant to MCU and SWPF. Operating and transfer conditions examined for the purpose ofmore » this review include temperatures between 13 C (McLeskey, 2008) and 45 C (Fondeur, 2007) and concentrations from 0 to 3M in nitric acid as well as exposure of small amounts of entrained boric acid in the organic phase to the sodium hydroxide caustic wash stream. Experiments were also conducted to observe any chemical reactions and off-gas generation that could occur when 0.01 M boric acid solution mixes with 3 M nitric acid solution and vice versa. Based on the low concentration (0.01M) of boric acid in the MCU/SWPF strip acid and the moderate operating temperatures (13 C to 45 C), it is unlikely that crystallization of boric acid will occur in the acid strip solution under process or transfer conditions. Mixing experiments of boric and nitric acid show no measurable gas generation (< 1 cc of gas per liter of solution) under similar process conditions.« less

Regulation of antibacterial defense in the small intestine by the nuclear bile acid receptor.

PubMed

Inagaki, Takeshi; Moschetta, Antonio; Lee, Youn-Kyoung; Peng, Li; Zhao, Guixiang; Downes, Michael; Yu, Ruth T; Shelton, John M; Richardson, James A; Repa, Joyce J; Mangelsdorf, David J; Kliewer, Steven A

2006-03-07

Obstruction of bile flow results in bacterial proliferation and mucosal injury in the small intestine that can lead to the translocation of bacteria across the epithelial barrier and systemic infection. These adverse effects of biliary obstruction can be inhibited by administration of bile acids. Here we show that the farnesoid X receptor (FXR), a nuclear receptor for bile acids, induces genes involved in enteroprotection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation. Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier. These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow.

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

USGS Publications Warehouse

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.

Cloud condensation nuclei activation of limited solubility organic aerosol

NASA Astrophysics Data System (ADS)

Huff Hartz, Kara E.; Tischuk, Joshua E.; Chan, Man Nin; Chan, Chak K.; Donahue, Neil M.; Pandis, Spyros N.

The cloud condensation nuclei (CCN) activation of 19 organic species with water solubilities ( Csat) ranging from 10 -4 to 10 2 g solute 100 g -1 H 2O was measured. The organic particles were generated by nebulization of an aqueous or an alcohol solution. Use of alcohols as solvents enables the measurement of low solubility, non-volatile organic CCN activity and reduces the likelihood of residual water in the aerosol. The activation diameter of organic species with very low solubility in water ( Csat<0.3 g 100 g -1 H 2O) is in agreement with Köhler theory using the bulk solubility (limited solubility case) of the organic in water. Many species, including 2-acetylbenzoic acid, aspartic acid, azelaic acid, glutamic acid, homophthalic acid, phthalic acid, cis-pinonic acid, and salicylic acid are highly CCN active in spite of their low solubility (0.3 g 100 g -1 H 2O< Csat<1 g 100 g -1 H 2O), and activate almost as if completely water soluble. The CCN activity of most species is reduced, if the particles are produced using non-aqueous solvents. The existence of the particles in a metastable state at low RH can explain the observed enhancement in CCN activity beyond the levels suggested by their solubility.

Soluble phosphate fertilizer production using acid effluent from metallurgical industry.

PubMed

Mattiello, Edson M; Resende Filho, Itamar D P; Barreto, Matheus S; Soares, Aline R; Silva, Ivo R da; Vergütz, Leonardus; Melo, Leônidas C A; Soares, Emanuelle M B

2016-01-15

Preventive and effective waste management requires cleaner production strategies and technologies for recycling and reuse. Metallurgical industries produce a great amount of acid effluent that must be discarded in a responsible manner, protecting the environment. The focus of this study was to examine the use of this effluent to increase reactivity of some phosphate rocks, thus enabling soluble phosphate fertilizer production. The effluent was diluted in deionized water with the following concentrations 0; 12.5; 25; 50; 75% (v v(-1)), which were added to four natural phosphate rocks: Araxá, Patos, Bayovar and Catalão and then left to react for 1 h and 24 h. There was an increase in water (PW), neutral ammonium citrate (PNAC) and citric acid (PCA) soluble phosphorus fractions. Such increases were dependent of rock type while the reaction time had no significant effect (p < 0.05) on the chemical and mineralogical phosphate characteristics. Phosphate fertilizers with low toxic metal concentrations and a high level of micronutrients were produced compared to the original natural rocks. The minimum amount of total P2O5, PNAC and PW, required for national legislation for phosphate partially acidulated fertilizer, were met when using Catalão and the effluent at the concentration of 55% (v v(-1)). Fertilizer similar to partially acidulated phosphate was obtained when Bayovar with effluent at 37.5% (v v(-1)) was used. Even though fertilizers obtained from Araxá and Patos did not contain the minimum levels of total P2O5 required by legislation, they can be used as a nutrient source and for acid effluent recycling and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

Water-soluble dicarboxylic acids and ketocarboxylic acids in the aerosols collected during ACE-Asia/C-130 aircraft campaign 2001

NASA Astrophysics Data System (ADS)

Kawamura, K.; Mochida, M.; Uemoto, N.; Bertram, T.; Huebert, B.

2001-12-01

During the ACE-Asia campaign with C-130 aircraft, aerosol samples were collected over the western North Pacific, East China Sea, and Japan Sea, as well as over Japanese Islands and Korean Peninsula in 8 April to 3 May 2001. The filter samples (N=15) were extracted with organic-free pure water to separate water-soluble dicarboxylic acids and related compounds. The extracts were reacted with 14% BF3 in n-butanol and the dibutyl esters and other derivatives were determined using a capillary GC and GC/MS. The results showed that 14 species of diacids (C2-C11) and 4 species of ketoacids (C2-C4) were detected in the aerosols over the East Asia. Total concentrations of the diacids were 113-500 (av. 330) ng/m3 whereas those of ketoacids were 43-260 (av. 103) ng/m3. The concentrations are equivalent to or more abundant than those reported for the urban Tokyo atmosphere in this season on the ground level. All the samples showed that oxalic acid (C2) is the most abundant diacid, which accounted for 58-83% of total diacids. These values are greater than that (ca. 50%) reported in the urban air near the ground, suggesting that oxalic acid is preferentially produced and/or longer diacids are selectively decomposed in the upper troposphere. Malonic (C3) acid is the second most abundant species followed by succinic (C4) acid. Longer diacids are less abundant, but azelaic (C9) acid is generally more abundant than C6-C8 diacids. Glyoxylic acid (C2) is the most abundant ketoacid followed by pyruvic acid. However, C3 and C4 omega-oxoacids were found as minor species. Although oxalic acid is the dominant component in the aerosols, few samples showed the predominance of glyoxylic acid over oxalic acid. This feature has not been reported for the urban aerosols collected near the ground level. We will discuss a potential photochemical production of water-soluble organic acids in the upper troposphere over the eastern ridge of the Asian continent.

Partially soluble organics as cloud condensation nuclei: Role of trace soluble and surface active species

NASA Astrophysics Data System (ADS)

Broekhuizen, K.; Kumar, P. Pradeep; Abbatt, J. P. D.

2004-01-01

The ability of partially soluble organic species to act as cloud condensation nuclei (CCN) has been studied. A Köhler model incorporating solute solubility and droplet surface tension describes the behavior of solid adipic and succinic acid particles, whereas solid azelaic acid activates much more efficiently that predicted. In addition, it was shown that trace levels of either sulfate or surface active species have a dramatic effect on the activation of adipic acid, a moderately soluble organic, as predicted by the full Köhler model. For internally mixed particles in the atmosphere, these effects will greatly enhance the role of organic aerosols as CCN.

The modified extended Hansen method to determine partial solubility parameters of drugs containing a single hydrogen bonding group and their sodium derivatives: benzoic acid/Na and ibuprofen/Na.

PubMed

Bustamante, P; Pena, M A; Barra, J

2000-01-20

Sodium salts are often used in drug formulation but their partial solubility parameters are not available. Sodium alters the physical properties of the drug and the knowledge of these parameters would help to predict adhesion properties that cannot be estimated using the solubility parameters of the parent acid. This work tests the applicability of the modified extended Hansen method to determine partial solubility parameters of sodium salts of acidic drugs containing a single hydrogen bonding group (ibuprofen, sodium ibuprofen, benzoic acid and sodium benzoate). The method uses a regression analysis of the logarithm of the experimental mole fraction solubility of the drug against the partial solubility parameters of the solvents, using models with three and four parameters. The solubility of the drugs was determined in a set of solvents representative of several chemical classes, ranging from low to high solubility parameter values. The best results were obtained with the four parameter model for the acidic drugs and with the three parameter model for the sodium derivatives. The four parameter model includes both a Lewis-acid and a Lewis-base term. Since the Lewis acid properties of the sodium derivatives are blocked by sodium, the three parameter model is recommended for these kind of compounds. Comparison of the parameters obtained shows that sodium greatly changes the polar parameters whereas the dispersion parameter is not much affected. Consequently the total solubility parameters of the salts are larger than for the parent acids in good agreement with the larger hydrophilicity expected from the introduction of sodium. The results indicate that the modified extended Hansen method can be applied to determine the partial solubility parameters of acidic drugs and their sodium salts.

Enhanced solubility and antioxidant activity of chlorogenic acid-chitosan conjugates due to the conjugation of chitosan with chlorogenic acid.

PubMed

Rui, Liyun; Xie, Minhao; Hu, Bing; Zhou, Li; Saeeduddin, Muhammad; Zeng, Xiaoxiong

2017-08-15

Chlorogenic acid-chitosan conjugate was synthesized by introducing of chlorogenic acid onto chitosan with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole. The data of UV-vis, FT-IR and NMR for chlorogenic acid-chitosan conjugates demonstrated the successful conjugation of chlorogenic acid with chitosan. Compared to chitosan, chlorogenic acid-chitosan conjugates exhibited increased solubility in distilled water, 1% acetic acid solution (v/v) or 50% ethanol solution (v/v) containing 0.5% acetic acid. Moreover, chlorogenic acid-chitosan conjugates showed dramatic enhancements in metal ion chelating activity, total antioxidant capacity, scavenging activities on 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) and superoxide radicals, inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching, and protective effect on H 2 O 2 -induced oxidative injury of PC12 cells. Particularly, chlorogenic acid-chitosan conjugate exhibited higher inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching than chlorogenic acid. The results suggested that chlorogenic acid-chitosan conjugates could serve as food supplements to enhance the function of foods in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Conjugation of curcumin onto hyaluronic acid enhances its aqueous solubility and stability.

PubMed

Manju, S; Sreenivasan, K

2011-07-01

Polymer-drug conjugates have gained much attention largely to circumvent lower drug solubility and to enhance drug stability. Curcumin is widely known for its medicinal properties including its anticancer efficacy. One of the serious drawbacks of curcumin is its poor water solubility which leads to reduced bioavailability. With a view to address these issues, we synthesized hyaluronic acid-curcumin (HA-Cur) conjugate. The drug conjugate was characterized using FT-IR, NMR, Dynamic light scattering and TEM techniques. The conjugates, interestingly found to assembles as micelles in aqueous phase. The formation of micelles seems to improve the stability of the drug in physiological pH. We also assessed cytotoxicity of the conjugate using L929 fibroblast cells and quantified by MTT assay. Copyright © 2011 Elsevier Inc. All rights reserved.

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

PubMed

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.

Anhydrous trifluoroacetic acid pretreatment converts insoluble polyglutamine peptides to soluble monomers.

PubMed

Burra, Gunasekhar; Thakur, Ashwani Kumar

2015-12-01

The data provided in this article are related to the research article entitled "Unaided trifluoroacetic acid pretreatment solubilizes polyglutamine (polyGln) peptides and retains their biophysical properties of aggregation" by Burra and Thakur (in press) [1]. This research article reports data from size exclusion chromatography (SEC), reversed phase-high performance liquid chromatography (RP-HPLC) and mass spectrometry (MS) assays. This data show that trifluoroacetic acid (TFA) has the ability to convert insoluble polyGln peptides to soluble monomers. The data also clarify the possibility of trifluoroacetylation modification caused due to TFA. We hope the data presented here will enhance the understanding of polyGln disaggregation and solubilization. For more insightful and useful discussions, see the research article published in Analytical Biochemistry: Methods in the Biological Sciences (Burra and Thakur, in press [1]).

Lack of periconceptional vitamins or supplements that contain folic acid and diabetes mellitus-associated birth defects.

PubMed

Correa, Adolfo; Gilboa, Suzanne M; Botto, Lorenzo D; Moore, Cynthia A; Hobbs, Charlotte A; Cleves, Mario A; Riehle-Colarusso, Tiffany J; Waller, D Kim; Reece, E Albert

2012-03-01

The purpose of this study was to examine the risk of birth defects in relation to diabetes mellitus and the lack of use of periconceptional vitamins or supplements that contain folic acid. The National Birth Defects Prevention Study (1997-2004) is a multicenter, population-based case-control study of birth defects (14,721 cases and 5437 control infants). Cases were categorized into 18 types of heart defects and 26 noncardiac birth defects. We estimated odds ratios for independent and joint effects of preexisting diabetes mellitus and a lack of periconceptional use of vitamins or supplements that contain folic acid. The pattern of odds ratios suggested an increased risk of defects that are associated with diabetes mellitus in the absence vs the presence of the periconceptional use of vitamins or supplements that contain folic acid. The lack of periconceptional use of vitamins or supplements that contain folic acid may be associated with an excess risk for birth defects due to diabetes mellitus. Published by Mosby, Inc.

Determination of Abraham model solute descriptors for the monomeric and dimeric forms of trans-cinnamic acid using measured solubilities from the Open Notebook Science Challenge.

PubMed

Bradley, Jean-Claude; Abraham, Michael H; Acree, William E; Lang, Andrew Sid; Beck, Samantha N; Bulger, David A; Clark, Elizabeth A; Condron, Lacey N; Costa, Stephanie T; Curtin, Evan M; Kurtu, Sozit B; Mangir, Mark I; McBride, Matthew J

2015-01-01

Calculating Abraham descriptors from solubility values requires that the solute have the same form when dissolved in all solvents. However, carboxylic acids can form dimers when dissolved in non-polar solvents. For such compounds Abraham descriptors can be calculated for both the monomeric and dimeric forms by treating the polar and non-polar systems separately. We illustrate the method of how this can be done by calculating the Abraham descriptors for both the monomeric and dimeric forms of trans-cinnamic acid, the first time that descriptors for a carboxylic acid dimer have been obtained. Abraham descriptors were calculated for the monomeric form of trans-cinnamic acid using experimental solubility measurements in polar solvents from the Open Notebook Science Challenge together with a number of water-solvent partition coefficients from the literature. Similarly, experimental solubility measurements in non-polar solvents were used to determine Abraham descriptors for the trans-cinnamic acid dimer. Abraham descriptors were calculated for both the monomeric and dimeric forms of trans-cinnamic acid. This allows for the prediction of further solubilities of trans-cinnamic acid in both polar and non-polar solvents with an error of about 0.10 log units. Graphical abstractMolar concentration of trans-cinnamic acid in various polar and non-polar solvents.

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

PubMed

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.

Nitric oxide (NO), the only nitrogen monoxide redox form capable of activating soluble guanylyl cyclase.

PubMed

Dierks, E A; Burstyn, J N

1996-06-28

In the present study, we determined that of the redox forms of nitrogen monoxide, NO-, NO and NO+, only NO significantly activates soluble guanylyl cyclase (GTP pyrophosphate-lyase cyclizing, EC 4.6.1.2). Neither of the NO-donors tested, Angeli's salt (Na2N2O3) or Piloty's acid (C6H5SO2NHOH), caused a change in the guanylyl cyclase activity relative to the basal activity level. Interference by other reaction products was eliminated as a possible explanation for the lack of activation. To the extent that NO+ could be stabilized in aqueous solution, by dissolution of the nitrosonium salt NOPF6 in dry organic solvent prior to addition to the enzyme in buffer, NO+ had no effect on the activity of soluble guanylyl cyclase. The counter-ion, PF6-, had a minimal effect on the enzyme activity and, therefore was, not responsible for the lack of activation by NO+. These observations suggest that NO- is the natural activator of soluble guanylyl cyclase and is reasonably identical with endothelium-derived relaxing factor, the physiological regulator of soluble guanylyl cyclase activity.

Water-soluble low-molecular-weight organic acids in automorphic loamy soils of the tundra and taiga zones

NASA Astrophysics Data System (ADS)

Shamrikova, E. V.; Gruzdev, I. V.; Punegov, V. V.; Khabibullina, F. M.; Kubik, O. S.

2013-06-01

The formation features of water-soluble low-molecular-weight organic acids (LMWOAs) in a zonal series of automorphic soils on loose silicate rocks from the middle taiga to the southern tundra (typical podzolic, gley-podzolic, and surface-gley tundra soils) were first revealed by gas chromatography mass spectrometry and gas-liquid chromatography. The content of LMWOAs varies within the range of 1-14 mg/dm3, which corresponds to 1-5% of the total carbon of the water-soluble soil organic matter. It has been shown that a subzonal feature of gley-podzolic soils in the northern taiga is the high content of LMWOAs, including primarily the strongest aliphatic hydroxyl acids. Possible mechanisms of their formation and accumulation in soils have been considered.

Secondary formation of water-soluble organic acids and α-dicarbonyls and their contributions to total carbon and water-soluble organic carbon: Photochemical aging of organic aerosols in the Arctic spring

NASA Astrophysics Data System (ADS)

Kawamura, Kimitaka; Kasukabe, Hideki; Barrie, Leonard A.

2010-11-01

Water-soluble dicarboxylic acids (C2-C12), ketocarboxylic acids (C2-C6, C9), and α-dicarbonyls (glyoxal and methylglyoxal) were determined in the Arctic aerosols collected in winter to early summer, as well as aerosol total carbon (TC) and water-soluble organic carbon (WSOC). Concentrations of TC and WSOC gradually decreased from late February to early June with a peak in spring, indicating a photochemical formation of water-soluble organic aerosols at a polar sunrise. We found that total (C2-C11) diacids (7-84 ng m-3) increased at polar sunrise by a factor of 4 and then decreased toward summer. Their contributions to TC (average 4.0%) peaked in early April and mid-May. The contribution of total diacids to WSOC was on average 7.1%. It gradually increased from February (5%) to a maximum in April (12.7%) with a second peak in mid-May (10.4%). Although oxalic acid (C2) is the dominant diacid until April, its predominance was replaced by succinic acid (C4) after polar sunrise. This may indicate that photochemical production of C2 was overwhelmed by its degradation when solar radiation was intensified and the atmospheric transport of its precursors from midlatitudes to the Arctic was ended in May. Interestingly, the contributions of azelaic (C9) and ω-oxobutanoic acids to WSOC increased in early summer possibly due to an enhanced emission of biogenic unsaturated fatty acids from the ocean followed by photochemical oxidation in the atmosphere. An enhanced contribution of diacids to TC and WSOC at polar sunrise may significantly alter the hygroscopic properties of organic aerosols in the Arctic.

Atmospheric transport of mineral dust from the Indo-Gangetic Plain: Temporal variability, acid processing, and iron solubility

NASA Astrophysics Data System (ADS)

Srinivas, Bikkina; Sarin, M. M.; Rengarajan, R.

2014-08-01

transport of chemical constituents from the Indo-Gangetic Plain (IGP) to the Bay of Bengal is a conspicuous seasonal feature that occurs during the late NE-monsoon (December-March). With this perspective, aerosol composition and abundance of mineral dust have been studied during November 2009 to March 2010 from a sampling site (Kharagpur: 22.3°N, 87.3°E) in the IGP, representing the atmospheric outflow to the Bay of Bengal. The chemical composition of PM2.5 suggests the dominance of nss-SO42- (6.9-24.3 µg m-3); whereas the abundance of mineral dust varied from 3 to 18 µg m-3. The concentration of aerosol iron (FeTot) and its fractional solubility (Fews % = Fews/FeTot *100, where Fews is the water-soluble fraction of FeTot) varied from 60 to 1144 ng m-3 and from 6.7 to 26.5%, respectively. A striking similarity in the temporal variability of total inorganic acidity (TIA = NO3- + nss-SO42-) and Fews (%) provides evidence for acid processing of mineral dust (alluvium) during atmospheric transport from the IGP. The contribution of TIA to water-soluble inorganic species [(nss-SO42- + NO3-)/ΣWSIS], mass ratios of Ca/Al and Fe/Al, and abundance of dust (%) and Fews (%) in the IGP-outflow are similar to the aerosol composition over the Bay of Bengal. With the rapid increase in anthropogenic activities over south and south-east Asia, the enhanced fractional solubility of aerosol iron (attributed to acid processing of mineral dust) has implications to further increase in the air-sea deposition of Fe to the Ocean surface.

Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex.

PubMed

Huan, Yan; Zhang, Sha; Vardhanabhuti, Bongkosh

2016-02-01

Acid-induced gelation properties of heated whey protein isolate (WPI) and carboxymethylcellulose (CMC) soluble complex were investigated as a function of CMC molecular weight (270, 680, and 750 kDa) and concentrations (0% to 0.125%). Heated WPI-CMC soluble complex with 6% protein was made by heating biopolymers together at pH 7.0 and 85 °C for 30 min and diluted to 5% protein before acid-induced gelation. Acid-induced gel formed from heated WPI-CMC complexes exhibited increased hardness and decreased water holding capacity with increasing CMC concentrations but gel strength decreased at higher CMC content. The highest gel strength was observed with CMC 750 k at 0.05%. Gels with low CMC concentration showed homogenous microstructure which was independent of CMC molecular weight, while increasing CMC concentration led to microphase separation with higher CMC molecular weight showing more extensive phase separation. When heated WPI-CMC complexes were prepared at 9% protein the acid gels showed improved gel hardness and water holding capacity, which was supported by the more interconnected protein network with less porosity when compared to complexes heated at 6% protein. It is concluded that protein concentration and biopolymer ratio during complex formation are the major factors affecting gel properties while the effect of CMC molecular weight was less significant. © 2016 Institute of Food Technologists®

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

PubMed

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.

Uptake and Dissolution of Gaseous Ethanol in Sulfuric Acid

NASA Technical Reports Server (NTRS)

Michelsen, Rebecca R.; Staton, Sarah J. R.; Iraci, Laura T.

2006-01-01

The solubility of gas-phase ethanol (ethyl alcohol, CH3CH2OH, EtOH) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (209-237 K) and acid composition (39-76 wt % H2SO4). Ethanol is very soluble under these conditions: effective Henry's law coefficients, H*, range from 4 x 10(exp 4) M/atm in the 227 K, 39 wt % acid to greater than 10(exp 7) M/atm in the 76 wt % acid. In 76 wt % sulfuric acid, ethanol solubility exceeds that which can be precisely determined using the Knudsen cell technique but falls in the range of 10(exp 7)-10(exp 10) M/atm. The equilibrium concentration of ethanol in upper tropospheric/lower stratospheric (UT/LS) sulfate particles is calculated from these measurements and compared to other small oxygenated organic compounds. Even if ethanol is a minor component in the gas phase, it may be a major constituent of the organic fraction in the particle phase. No evidence for the formation of ethyl hydrogen sulfate was found under our experimental conditions. While the protonation of ethanol does augment solubility at higher acidity, the primary reason H* increases with acidity is an increase in the solubility of molecular (i.e., neutral) ethanol.

Lack of periconceptional vitamins or supplements that contain folic acid and diabetes mellitus–associated birth defects

PubMed Central

Correa, Adolfo; Gilboa, Suzanne M.; Botto, Lorenzo D.; Moore, Cynthia A.; Hobbs, Charlotte A.; Cleves, Mario A.; Riehle-Colarusso, Tiffany J.; Waller, D. Kim; Reece, E. Albert

2016-01-01

OBJECTIVE The purpose of this study was to examine the risk of birth defects in relation to diabetes mellitus and the lack of use of periconceptional vitamins or supplements that contain folic acid. STUDY DESIGN The National Birth Defects Prevention Study (1997-2004) is a multicenter, population-based case-control study of birth defects (14,721 cases and 5437 control infants). Cases were categorized into 18 types of heart defects and 26 noncardiac birth defects. We estimated odds ratios for independent and joint effects of preexisting diabetes mellitus and a lack of periconceptional use of vitamins or supplements that contain folic acid. RESULTS The pattern of odds ratios suggested an increased risk of defects that are associated with diabetes mellitus in the absence vs the presence of the periconceptional use of vitamins or supplements that contain folic acid. CONCLUSION The lack of periconceptional use of vitamins or supplements that contain folic acid may be associated with an excess risk for birth defects due to diabetes mellitus. PMID:22284962

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

PubMed

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.

Phenolic acids and antioxidant activity of distillers dried grains with solubles (DDGS) as compared with corn

USDA-ARS?s Scientific Manuscript database

Sample sets of ground corn and the corresponding distillers dried grains with solubles (DDGS) were collected from three commercial plants in Iowa. Phenolic acids were analyzed by high performance liquid chromatography coupled with diode array and/or mass spectrometry. The antioxidant activity was ...

Phenolic acids and antioxidant capacity of distillers dried grains with solubles (DDGS) as compared with corn

USDA-ARS?s Scientific Manuscript database

Three sets of ground corn and the corresponding distillers dried grains with solubles (DDGS) were collected from three commercial plants and analyzed for individual phenolic acids by high performance liquid chromatography coupled with diode array and/or mass spectrometry and for antioxidant capacity...

The relationship between surface tension and the industrial performance of water-soluble polymers prepared from acid hydrolysis lignin, a saccharification by-product from woody materials.

PubMed

Matsushita, Yasuyuki; Imai, Masanori; Iwatsuki, Ayuko; Fukushima, Kazuhiko

2008-05-01

In this study, water-soluble anionic and cationic polymers were prepared from sulfuric acid lignin (SAL), an acid hydrolysis lignin, and the relationship between the surface tension of these polymers and industrial performance was examined. The SAL was phenolized (P-SAL) to enhance its solubility and reactivity. Sulfonation and the Mannich reaction with aminocarboxylic acids produced water-soluble anionic polymers and high-dispersibility gypsum paste. The dispersing efficiency increased as the surface tension decreased, suggesting that the fluidity of the gypsum paste increased with the polymer adsorption on the gypsum particle surface. Water-soluble cationic polymers were prepared using the Mannich reaction with dimethylamine. The cationic polymers showed high sizing efficiency under neutral papermaking conditions; the sizing efficiency increased with the surface tension. This suggests that the polymer with high hydrophilicity spread in the water and readily adhered to the pulp surface and the rosin, showing good retention.

Modulatory influence of sandalwood oil on mouse hepatic glutathione S-transferase activity and acid soluble sulphydryl level.

PubMed

Banerjee, S; Ecavade, A; Rao, A R

1993-02-01

The effect of the oil from the wood of Santalum album on glutathione S-transferase (GST) activity and acid soluble sulphydryl (SH) levels in the liver of adult male Swiss albino mice was investigated. Oral feeding by gavage to mice each day with 5 and 15 microliters sandalwood oil for 10 and 20 days exhibited an increase in GST activity in time- and dose-responsive manners. Feeding a dose of 5 microliters sandalwood oil for 10 and 20 days caused, respectively, a 1.80-fold (P < 0.001) and 1.93-fold (P < 0.001) increase in GST enzyme activity, while feeding a dose of 15 microliters of the oil per day for 10 and 20 days induced, respectively, 4.73-fold (P < 0.001) and 6.10-fold (P < 0.001) increases in the enzyme's activity. In addition, there were 1.59-fold (P < 0.001) and 1.57 (P < 0.001) increases in acid-soluble SH levels in the hepatic tissue of the mice following feeding of the oil at the dose levels of 5 and 15 microliters for 10 days. Furthermore, mice fed on a diet containing 1% 2(3)-butyl-4-hydroxyanisole (positive control) also showed an increase in hepatic GST activity and SH levels. Enhancement of GST activity and acid-soluble SH levels are suggestive of a possible chemopreventive action of sandalwood oil on carcinogenesis through a blocking mechanism.

Efficacy of reducing sugar and phenol-sulfuric acid assays for analysis of soluble carbohydrates in feedstuffs

USDA-ARS?s Scientific Manuscript database

Reducing sugar (RSA) and phenol–sulfuric acid (PSA) assays are commonly used to analyze water-soluble carbohydrates. However, questions have arisen as to their accuracy for measurement of feedstuffs with diverse carbohydrate profiles. This study evaluated the efficacy of RSA and PSA as they would co...

Effect of hydrotalcite-like compounds on the aqueous solubility of some poorly water-soluble drugs.

PubMed

Ambrogi, Valeria; Fardella, Giuseppe; Grandolini, Giuliano; Nocchetti, Morena; Perioli, Luana

2003-07-01

A new approach of improving drug dissolution properties is described. This method exploits the property of a carrier owing to the hydrotalcite-type anionic clays (HTlc). HTlc is an inorganic layered solid that lodges anionic compounds among its layers. As HTlc dissolves at acidic pH values (pH < 4), the anions intercalated among the layers are promptly released in the medium. In this article some nonsteroidal antiinflammatory drugs were chosen as models of poorly water-soluble drugs. They were intercalated in HTlc and solubility measurements in acidic medium were performed. A remarkable improvement of drug solubility was observed especially in the case of indomethacin. Copyright 2003 Wiley-Liss, Inc. and the American Pharmacists Association

Effects of solution degassing on solubility, crystal growth and dissolution-Case study: Salicylic acid in methanol

NASA Astrophysics Data System (ADS)

Seidel, J.; Ulrich, J.

2017-02-01

The influence of dissolved gases on the crystallization parameter solubility, MZW, growth and dissolution rates was investigated experimentally using degassed and non-degassed (air-saturated) solutions. The results of this study show that degassing has no effect on the solubility curve of the used model substance salicylic acid (SA) in methanol (MeOH). This reveals in the assumption that a thermodynamic effect of dissolved gases can be excluded. Growth rates were measured by means of a desupersaturation method and the results indicate that the growth rates of SA are not affected by degassing. The results of the dissolution rate measurements reveal a distinct decrease in dissolution rates for non-degassed solutions compared to degassed solutions, especially, at low temperature (10 °C). To explain this phenomenon the gas solubility, represented by oxygen, in MeOH in dependence on the SA concentration was estimated by means of Hansen Solubility Parameters (HSP) [1]. It was found that the oxygen solubility decreases with increasing SA content which explains the inhibition of crystal dissolution in non-degassed solution compared to degassed solution. Moreover, this kind of 'drowing-out' mechanism would not appear in growth rate measurements, where indeed no effect of degassing could be observed.

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

PubMed Central

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

2015-01-01

Background 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. Results 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. Conclusion 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 Plant Breeding and Acclimatization Institute, National Research Institute. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25410263

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.

PubMed

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed Central

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

Kinetics during the redox biotransformation of pollutants mediated by immobilized and soluble humic acids.

PubMed

Cervantes, Francisco J; Martínez, Claudia M; Gonzalez-Estrella, Jorge; Márquez, Arturo; Arriaga, Sonia

2013-03-01

The aim of this study was to elucidate the kinetic constraints during the redox biotransformation of the azo dye, Reactive Red 2 (RR2), and carbon tetrachloride (CT) mediated by soluble humic acids (HAs) and immobilized humic acids (HAi), as well as by the quinoid model compounds, anthraquinone-2,6-disulfonate (AQDS) and 1,2-naphthoquinone-4-sulfonate (NQS). The microbial reduction of both HAs and HAi by anaerobic granular sludge (AGS) was the rate-limiting step during decolorization of RR2 since the reduction of RR2 by reduced HAi proceeded at more than three orders of magnitute faster than the electron-transferring rate observed during the microbial reduction of HAi by AGS. Similarly, the reduction of RR2 by reduced AQDS proceeded 1.6- and 1.9-fold faster than the microbial reduction of AQDS by AGS when this redox mediator (RM) was supplied in soluble and immobilized form, respectively. In contrast, the reduction of NQS by AGS occurred 1.6- and 19.2-fold faster than the chemical reduction of RR2 by reduced NQS when this RM was supplied in soluble and immobilized form, respectively. The microbial reduction of HAs and HAi by a humus-reducing consortium proceeded 1,400- and 790-fold faster than the transfer of electrons from reduced HAs and HAi, respectively, to achieve the reductive dechlorination of CT to chloroform. Overall, the present study provides elucidation on the rate-limiting steps involved in the redox biotransformation of priority pollutants mediated by both HAs and HAi and offers technical suggestions to overcome the kinetic restrictions identified in the redox reactions evaluated.

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

USDA-ARS?s Scientific Manuscript database

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...

Bioconcentration factors and lipid solubility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, S.; Baughman, G.L.

1991-03-01

The log-log relationship between bioconcentration and hydrophobicity breaks down for several medium and high molecular weight solutes that bioconcentrate either to a small extent or not at all. Much of the failure is attributed to the relatively low solubility of these compounds in lipid. Inclusion of a term in octanol solubility (in place of lipid solubility, which is generally unavailable) considerably improves the quality of the relationship (r = 0.95). It is speculated that the octanol solubility term compensates for the relatively low solubility of large compounds in lipid.

Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography.

PubMed

Qin, Xiaopeng; Liu, Fei; Wang, Guangcai; Weng, Liping

2012-12-01

An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used in this study. Under the experimental conditions, the UV peaks of salicylic acid and 2,3-dihydroxybenzoic acid were well separated from the peaks of humic acid in the chromatogram. Concentrations of the two small organic acids could be accurately determined from their peak areas. The concentration of humic acid in the mixture could then be derived from mass balance calculations. The measured results agreed well with the nominal concentrations. The detection limits are 0.05 mg/L and 0.01 mg/L for salicylic acid and 2,3-dihydroxybenzoic acid, respectively. Applicability of the method to natural samples was tested using groundwater, glacier, and river water samples (both original and spiked with salicylic acid and 2,3-dihydroxybenzoic acid) with a total organic carbon concentration ranging from 2.1 to 179.5 mg C/L. The results obtained are promising, especially for groundwater samples and river water samples with a total organic carbon concentration below 9 mg C/L. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water-soluble metal working fluids additives derived from the esters of acid anhydrides with higher alcohols for aluminum alloy materials.

PubMed

Yamamoto, Syutaro; Tomoda, Hideyuki; Watanabe, Shoji

2007-01-01

Water-soluble metal working fluids are used for processing of aluminum alloy materials. This short article describes properties of new additives in water-soluble metal working fluids for aluminum alloy materials. Many half esters or diesters were prepared from the reactions of higher alcohols with acid anhydrides. Interestingly, diesters of PTMG (tetrahydrofuran oligomer, MW = 650 and 1000) and polybutylene oxide (MW = 650) with maleic anhydride and succinic anhydride showed both of an excellent anti-corrosion property for aluminum alloy and a good hard water tolerance. The industrial soluble type processing oils including these additives also showed anti-corrosion property and hard water tolerance.

A comparison of water solubility enhancements of organic solutes by aquatic humic materials and commercial humic acids

USGS Publications Warehouse

Chlou, C.T.; Kile, D.E.; Brinton, T.I.; Malcolm, R.L.; Leenheer, J.A.; MacCarthy, P.

1987-01-01

Water solubility enhancements of 1,1-bis(p-chloro-phenyl)-2,2,2-trichloroethane (p,p???-DDT), 2,4,5,2???,5???-pentachlorobiphenyl (2,4,5,2???,5???-PCB), and 2,4,4???-tri-chlorobiphenyl (2,4,4???-PCB) by dissolved organic matter have been studied with the following samples: (1) acidic water samples from the Suwannee River, Georgia, and the Sopchoppy River, Florida; (2) a humic extract of a nearly neutral pH water from the Calcasieu River, Louisiana; (3) commercial humic acids from the Aldrich Chemical Co. and Fluka-Tridom Chemical Corp. The calculated partition coefficients on a dissolved organic carbon basis (Kdoc) for organic solutes with water samples and aquatic humic extracts from this and earlier studies indicate that the enhancement effect varies with the molecular composition of the aquatic humic materials. The Kdoc values with water and aquatic humic samples are, however, far less than the observed Kdoc values obtained with the two commercial samples, by factors of about 4-20. In view of this finding, one should be cautious in interpreting the effects of the dissolved organic matter on solubility enhancement of organic solutes on the basis of the use of commercial humic acids.

Automated, high-throughput platform for protein solubility screening using a split-GFP system

PubMed Central

Listwan, Pawel; Terwilliger, Thomas C.

2010-01-01

Overproduction of soluble and stable proteins for functional and structural studies is a major bottleneck for structural genomics programs and traditional biochemistry laboratories. Many high-payoff proteins that are important in various biological processes are “difficult to handle” as protein reagents in their native form. We have recently made several advances in enabling biochemical technologies for improving protein stability (http://www.lanl.gov/projects/gfp/), allowing stratagems for efficient protein domain trapping, solubility-improving mutations, and finding protein folding partners. In particular split-GFP protein tags are a very powerful tool for detection of stable protein domains. Soluble, stable proteins tagged with the 15 amino acid GFP fragment (amino acids 216–228) can be detected in vivo and in vitro using the engineered GFP 1–10 “detector” fragment (amino acids 1–215). If the small tag is accessible, the detector fragment spontaneously binds resulting in fluorescence. Here, we describe our current and on-going efforts to move this process from the bench (manual sample manipulation) to an automated, high-throughput, liquid-handling platform. We discuss optimization and validation of bacterial culture growth, lysis protocols, protein extraction, and assays of soluble and insoluble protein in multiple 96 well plate format. The optimized liquid-handling protocol can be used for rapid determination of the optimal, compact domains from single ORFS, collections of ORFS, or cDNA libraries. PMID:19039681

Solubility of carbamazepine co-crystals in ethanolic solution

NASA Astrophysics Data System (ADS)

Ramle, Noor Ashila; Rahim, Syarifah Abd; Anuar, Nornizar; El-Hadad, Omar

2017-08-01

The study aimed to determine the solubility of carbamazepine (CBZ) co-crystals formed from co-crystal formers (CCFs) of nicotinamide (NIC), saccharin (SAC), succinic acid (SUC) and fumaric acid (FUM) at various temperatures (25-50°C). High Performance Liquid Chromatography (HPLC) was used to determine the solubility and the X-Ray Powder Diffraction was used to characterize the crystals. The solubility of CBZ-NIC and CBZ-FUM co-crystals were found to be higher than the solubility of the CBZ for the range of studied temperatures. However, opposite findings was obtained for CBZ-SUC co-crystal as its solubility is lower than the solubility of CBZ. Different trend was found for CBZ-SAC co-crystal in which for temperature lower than 40°C, the solubility of CBZ crystal is higher than the CBZ-SAC co-crystal. The solubility of CBZ-SAC co-crystal is higher than the solubility of CBZ at a temperature above 40°C. CBZ co-crystals with NIC and FUM have shown to increase the solubility of CBZ by solubility ratio of 1.95 and 1.24 respectively. However, the CBZ co-crystal with SAC was found to have similar solubility value as the CBZ.

Modeling solubility, acid-base properties and activity coefficients of amoxicillin, ampicillin and (+)6-aminopenicillanic acid, in NaCl(aq) at different ionic strengths and temperatures.

PubMed

Crea, Francesco; Cucinotta, Daniela; De Stefano, Concetta; Milea, Demetrio; Sammartano, Silvio; Vianelli, Giuseppina

2012-11-20

The total solubility of three penicillin derivatives was determined, in pure water and NaCl aqueous solutions at different salt concentrations (from ∼0.15 to 1.0 mol L(-1) for ampicillin and amoxicillin, and from ∼0.05 to 2.0 mol L(-1) for (+)6-aminopenicillanic acid), using the shake-flask method for generating the saturated solutions, followed by potentiometric analysis. The knowledge of the pH of solubilization and of the protonation constants determined in the same experimental conditions, allowed us to calculate, by means of the mass balance equations, the solubility of the neutral species at different ionic strength values, to model its dependence on the salt concentration and to determine the corresponding values at infinite dilution. The salting parameter and the activity coefficients of the neutral species were calculated by the Setschenow equation. The protonation constants of ampicillin and amoxicillin, determined at different temperatures (from T=288.15 to 318.15K), from potentiometric and spectrophotometric measurements, were used to calculate, by means of the Van't Hoff equation, the temperature coefficients at different ionic strength values and the corresponding protonation entropies. The protonation enthalpies of the (+)6-aminopenicillanic acid were determined by isoperibol calorimetric titrations at T=298.15K and up to I=2.0 mol L(-1). The dependence of the protonation constants on ionic strength was modeled by means of the Debye-Hückel and SIT (Specific ion Interaction Theory) approaches, and the specific interaction parameters of the ionic species were determined. The hydrolysis of the β-lactam ring was studied by spectrophotometric and H NMR investigations as a function of pH, ionic strength and time. Potentiometric measurements carried out on the hydrolyzed (+)6-aminopenicillanic acid allowed us to highlight that the opened and the closed β-lactam forms of the (+)6-aminopenicillanic acid have quite different acid-base properties. An

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

PubMed

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.

Enhanced Aqueous Solubility of Long Wavelength Voltage-Sensitive Dyes by Covalent Attachment of Polyethylene Glycol

PubMed Central

Patrick, Michael J.; Ernst, Lauren A.; Waggoner, Alan S.; Thai, Dung; Salama, Guy

2011-01-01

Long wavelength voltage-sensitive dyes (VSDs) called Pittsburgh (PGH) dyes were recently synthesized by coupling various heterocyclic groups to a styryl-thiophene intermediate forming extended, partially rigidized chromophores. Unlike most styryl VSDs, dyes with a sulfonic acid anchor directly attached to the chromophore showed no solvatochromic absorption shifts. The limited water solubility of many long wavelength VSDs requires the use of surfactants to transport the dye through aqueous media and effectively label biological membranes. Here, we tested the chemical substitution of the sulfonic acid moiety with polyethyleneglycol (PEG) chains ranging from MW 750 to 5000, to overcome the poor solubility of VSDs while retaining their properties as VSDs. The chemical synthesis of PGH dyes and their PEG derivatives are described. The PEG-derivatives were soluble in aqueous solutions (> 1 mM) and still reported membrane potential changes. In frog and mouse hearts, the voltage sensitivity (ΔF/F per action potential) and spectral properties of PEG dyes were the same as the sulfonated analogs. Thus, the solubility of VSDs can be considerably improved with small polyethyleneglycol chains and can provide an effective approach to improve staining of excitable tissues and optical recordings of membrane potential. PMID:17912389

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

PubMed

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.

Synthesis of acid-soluble spore proteins by Bacillus subtilis.

PubMed

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.

Molecularly designed water soluble, intelligent, nanosize polymeric carriers.

PubMed

Pişkin, Erhan

2004-06-11

Intelligent polymers, also referred as "stimuli-responsive polymers" undergo strong property changes (in shape, surface characteristics, solubility, etc.) when only small changes in their environment (changes in temperature, pH, ionic strength light, electrical and magnetic field, etc.). They have been used in several novel applications, drug delivery systems, tissue engineering scaffolds, bioseparation, biomimetic actuators, etc. The most popular member of these type of polymers is poly(N-isopropylacrylamide) (poly(NIPA)) which exhibits temperature-sensitive character, in which the polymer chains change from water-soluble coils to water-insoluble globules in aqueous solution as temperature increases above the lower critical solution temperature (LCST) of the polymer. Copolymerization of NIPA with acrylic acid (AAc) allows the synthesis of both pH and temperature-responsive copolymers. This paper summarizes some of our related studies in which NIPA and its copolymers were synthesized and used as intelligent carriers in diverse applications.

Cellular Fatty Acid Composition, Soluble-Protein Profile, and Antimicrobial Resistance Pattern of Eubacterium lentum

PubMed Central

Mosca, Adriana; Summanen, Paula; Finegold, Sydney M.; De Michele, Giampiero; Miragliotta, Giuseppe

1998-01-01

Phenotypic heterogeneity among isolates of Eubacterium lentum has been recognized for many years. To better delineate their taxonomic relatedness, 29 clinical isolates of E. lentum were examined for soluble-protein content, cellular fatty acid profile, and antimicrobial resistance pattern in order to ascertain whether differences in these characteristics could be correlated with differences in biochemical activities. Among 29 isolates we could identify 6 that were different from all the others. These strains were coccobacilli with translucent colonies; they were catalase and H2S negative, not fluorescent under UV light, and susceptible to beta-lactam drugs; growth was not stimulated by arginine; and fatty acid analysis revealed the presence of straight-chain fatty acids. The remainder of the strains, including the type species, were pleomorphic bacilli with speckled colonies and were catalase and H2S positive; all but two were fluorescent under UV light; they were resistant to beta-lactam antibiotics; growth was greatly stimulated by arginine; and they demonstrated saturated branched-chain fatty acids. Our data suggest that E. lentum can be further differentiated into different types. PMID:9508307

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

PubMed

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.

The effect of relative solubility on crystal purity

NASA Astrophysics Data System (ADS)

Givand, Jeffrey Christopher

This study establishes the relationship between impurity incorporation in a crystal by lattice substitution and the solubility of that impurity in solution. The model system studied was L-isoleucine crystals contaminated by the isomorphic impurity L-leucine. Upon crystallization from aqueous solution by cooling, leucine is concentrated in the isoleucine unit cell through lattice substitution mechanisms. Attempts to reduce the degree of leucine incorporation via adjustments of the rate at which supersaturation is generated yielded marginal success. This work demonstrates that incorporation of leucine in the crystal can be considerably suppressed by reducing the solubility of product relative to the solubility of impurity. Changes to the relative solubility of the impurity were accomplished by the addition of various electrolytes and organic co-solvents to the aqueous amino acid solutions. The solubilities of the two amino acids were measured and compared to their solubilities in pure water. Changes in the ratio of pure-component solubilities were directly related to changes in crystal purity. This thermodynamic quantity of relative solubility was shown to be a key factor in determining impurity uptake by lattice substitution. In addition to the experimental observations, a fundamental thermodynamic link between relative solubility and crystal purity is established through this research. First, the amino acid solubility data as a function of temperature in all solvent mixtures were accurately correlated using a thermodynamic model. The parameters from this model were then adapted to a novel solid-solution thermodynamic model to express the crystal purity in terms of equilibrium solution impurity concentration. After the determination of one system specific parameter, the model is able to predict the crystal purity in a new solvent in which the pure-component solubilities are known. The ability of an electrolyte or co-solvent to improve crystal purity from a given

Synthesis, characterization, solubility and stability studies of hydrate cocrystal of antitubercular Isoniazid with antioxidant and anti-bacterial Protocatechuic acid

NASA Astrophysics Data System (ADS)

Mashhadi, Syed Muddassir Ali; Yunus, Uzma; Bhatti, Moazzam Hussain; Ahmed, Imtiaz; Tahir, Muhammad Nawaz

2016-08-01

Isoniazid is an important component used in "triple therapy" to combat tuberculosis. It has reduced Tabletting formulations stability. Anti-oxidants are obligatory to counter oxidative stress, pulmonary inflammation, and free radical burst from macrophages caused in tuberculosis and other diseases. In the present study a hydrate cocrystal of Isoniazid with anti-oxidant and anti-inflammatory and anti-bacterial Protocatechuic acid (3,4-dihydroxybenzoic acid) in 1:1 is reported. This Cocrystal may have improved tabletting stability and anti-oxidant properties. Cocrystal structure analysis confirmed the existence of pyridine-carboxylic acid synthon in the Cocrystal. Other synthons of different graph sets involving Nsbnd H···O and Osbnd H···N bonds are formed between hydrazide group of isoniazid and coformer. Solubility studies revealed that cocrystal is less soluble as compared to isoniazid in buffer at pH 7.4 at 22 °C while stability studies at 80 °C for 24 h period disclosed the fact that cocrystal has higher stability than that of isoniazid.

Correlation of second virial coefficient with solubility for proteins in salt solutions.

PubMed

Mehta, Chirag M; White, Edward T; Litster, James D

2012-01-01

In this work, osmotic second virial coefficients (B(22)) were determined and correlated with the measured solubilities for the proteins, α-amylase, ovalbumin, and lysozyme. The B(22) values and solubilities were determined in similar solution conditions using two salts, sodium chloride and ammonium sulfate in an acidic pH range. An overall decrease in the solubility of the proteins (salting out) was observed at high concentrations of ammonium sulfate and sodium chloride solutions. However, for α-amylase, salting-in behavior was also observed in low concentration sodium chloride solutions. In ammonium sulfate solutions, the B(22) are small and close to zero below 2.4 M. As the ammonium sulfate concentrations were further increased, B(22) values decreased for all systems studied. The effect of sodium chloride on B(22) varies with concentration, solution pH, and the type of protein studied. Theoretical models show a reasonable fit to the experimental derived data of B(22) and solubility. B(22) is also directly proportional to the logarithm of the solubility values for individual proteins in salt solutions, so the log-linear empirical models developed in this work can also be used to rapidly predict solubility and B(22) values for given protein-salt systems. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

Acid monomer analysis in waterborne polymer systems by targeted labeling of carboxylic acid functionality, followed by pyrolysis - gas chromatography.

PubMed

Brooijmans, T; Okhuijsen, R; Oerlemans, I; Schoenmakers, P J; Peters, R

2018-05-14

Pyrolysis - gas chromatography - (PyGC) is a common method to analyse the composition of natural and synthetic resins. The analysis of acid functionality in, for example, waterborne polyacrylates and polyurethanes polymers has proven to be difficult due to solubility issues, inter- and intramolecular interaction effects, lack of detectability in chromatographic analysis, and lack of thermal stability. Conventional analytical techniques, such as PyGC, cannot be used for the direct detection and identification of acidic monomers, due to thermal rearrangements that take place during pyrolysis. To circumvent this, the carboxylic acid groups are protected prior to thermal treatment by reaction with 2-bromoacetophenone. Reaction conditions are investigated and optimised wrt. conversion measurements. The aproach is applied to waterborne polyacryalates and the results are discussed. This approach enables identification and (semi)quantitative analysis of different acid functionalities in waterborne polymers by PyGC. Copyright © 2018 Elsevier B.V. All rights reserved.

Dissolving Carboxylic Acids and Primary Amines on the Overhead Projector

ERIC Educational Resources Information Center

Solomon, Sally D.; Rutkowsky, Susan A.

2010-01-01

Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the…

Water-soluble dietary fibers and cardiovascular disease.

PubMed

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.

Lack of correlation between serum soluble Fas/APO-1 levels and autoimmune disease.

PubMed

Goel, N; Ulrich, D T; St Clair, E W; Fleming, J A; Lynch, D H; Seldin, M F

1995-12-01

To determine whether elevated soluble Fas/APO-1 (sFas/APO-1) levels are associated with either autoimmune disease or evidence of flares in autoimmune disease. Thirty-seven serum samples were retrospectively obtained from normal controls and patients with laboratory evidence of autoimmune disease activity. These samples were assayed for sFas/APO-1 levels by an enzyme-linked immunosorbent assay, and hospital medical records were retrospectively reviewed for clinical and laboratory characteristics of the patients. Soluble Fas/APO-1 levels did not correlate with clinical diagnoses or laboratory abnormalities. The mean and range of sFas/APO-1 levels were similar in systemic lupus erythematosus patients (including those with active disease), patients with other autoimmune diseases, and normal controls. These data strongly suggest that measurement of sFas/APO-1 levels is unlikely to hold clinical value or play a role in the pathogenesis of autoimmune disease.

Long-term observation of water-soluble chemical components and acid-digested metals in the total suspended particles collected at Okinawa, Japan

NASA Astrophysics Data System (ADS)

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

Water-soluble polymers and compositions thereof

DOEpatents

Smith, B.F.; Robison, T.W.; Gohdes, J.W.

1999-04-06

Water-soluble polymers including functionalization from the group of amino groups, carboxylic acid groups, phosphonic acid groups, phosphonic ester groups, acylpyrazolone groups, hydroxamic acid groups, aza crown ether groups, oxy crown ethers groups, guanidinium groups, amide groups, ester groups, aminodicarboxylic groups, permethylated polyvinylpyridine groups, permethylated amine groups, mercaptosuccinic acid groups, alkyl thiol groups, and N-alkylthiourea groups are disclosed.

Water-soluble polymers and compositions thereof

DOEpatents

Smith, Barbara F.; Robison, Thomas W.; Gohdes, Joel W.

2002-01-01

Water-soluble polymers including functionalization from the group of amino groups, carboxylic acid groups, phosphonic acid groups, phosphonic ester groups, acylpyrazolone groups, hydroxamic acid groups, aza crown ether groups, oxy crown ethers groups, guanidinium groups, amide groups, ester groups, aminodicarboxylic groups, permethylated polvinylpyridine groups, permethylated amine groups, mercaptosuccinic acid groups, alkyl thiol groups, and N-alkylthiourea groups are disclosed.

Water-soluble polymers and compositions thereof

DOEpatents

Smith, Barbara F.; Robison, Thomas W.; Gohdes, Joel W.

1999-01-01

Water-soluble polymers including functionalization from the group of amino groups, carboxylic acid groups, phosphonic acid groups, phosphonic ester groups, acylpyrazolone groups, hydroxamic acid groups, aza crown ether groups, oxy crown ethers groups, guanidinium groups, amide groups, ester groups, aminodicarboxylic groups, permethylated polyvinylpyridine groups, permethylated amine groups, mercaptosuccinic acid groups, alkyl thiol groups, and N-alkylthiourea groups are disclosed.

Reprint of: Effects of solution degassing on solubility, crystal growth and dissolution-Case study: Salicylic acid in methanol

NASA Astrophysics Data System (ADS)

Seidel, J.; Ulrich, J.

2017-07-01

The influence of dissolved gases on the crystallization parameter solubility, MZW, growth and dissolution rates was investigated experimentally using degassed and non-degassed (air-saturated) solutions. The results of this study show that degassing has no effect on the solubility curve of the used model substance salicylic acid (SA) in methanol (MeOH). This reveals in the assumption that a thermodynamic effect of dissolved gases can be excluded. Growth rates were measured by means of a desupersaturation method and the results indicate that the growth rates of SA are not affected by degassing. The results of the dissolution rate measurements reveal a distinct decrease in dissolution rates for non-degassed solutions compared to degassed solutions, especially, at low temperature (10 °C). To explain this phenomenon the gas solubility, represented by oxygen, in MeOH in dependence on the SA concentration was estimated by means of Hansen Solubility Parameters (HSP) [1]. It was found that the oxygen solubility decreases with increasing SA content which explains the inhibition of crystal dissolution in non-degassed solution compared to degassed solution. Moreover, this kind of 'drowing-out' mechanism would not appear in growth rate measurements, where indeed no effect of degassing could be observed.

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.

PubMed

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.

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

PubMed

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.

Biowaiver Monographs for Immediate-Release Solid Oral Dosage Forms: Folic Acid.

PubMed

Hofsäss, Martin A; Souza, Jacqueline de; Silva-Barcellos, Neila M; Bellavinha, Karime R; Abrahamsson, Bertil; Cristofoletti, Rodrigo; Groot, D W; Parr, Alan; Langguth, Peter; Polli, James E; Shah, Vinod P; Tajiri, Tomokazu; Mehta, Mehul U; Dressman, Jennifer B

2017-12-01

This work presents a review of literature and experimental data relevant to the possibility of waiving pharmacokinetic bioequivalence studies in human volunteers for approval of immediate-release solid oral pharmaceutical forms containing folic acid as the single active pharmaceutical ingredient. For dosage forms containing 5 mg folic acid, the highest dose strength on the World Health Organization Essential Medicines List, the dose/solubility ratio calculated from solubility studies was higher than 250 mL, corresponding to a classification as "not highly soluble." Small, physiological doses of folic acid (≤320 μg) seem to be absorbed completely via active transport, but permeability data for higher doses of 1-5 mg are inconclusive. Following a conservative approach, folic acid is classified as a Biopharmaceutics Classification System class IV compound until more reliable data become available. Commensurate with its solubility characteristics, the results of dissolution studies indicated that none of the folic acid products evaluated showed rapid dissolution in media at pH 1.2 or 4.5. Therefore, according to the current criteria of the Biopharmaceutics Classification System, the biowaiver approval procedure cannot be recommended for immediate-release solid oral dosage forms containing folic acid. Copyright © 2017 American Pharmacists Association®. All rights reserved.

Dramatic improvement of the solubility of pseudolaric acid B by cyclodextrin complexation: preparation, characterization and validation.

PubMed

Chi, Liandi; Liu, Ruihao; Guo, Tao; Wang, Manli; Liao, Zuhua; Wu, Li; Li, Haiyan; Wu, Deling; Zhang, Jiwen

2015-02-20

As one of the most important technologies to improve the solubility of poorly water-soluble drugs, the solubilization effects of cyclodextrins (CDs) complexation are, on occasions, not as large as expected, which tends to detract from the wider application of CDs. In this study, a dramatic improvement of the solubility of pseudolaric acid B (PAB) by CDs has been found with a 600 fold increase by HP-β-CD complexation. In addition, the solubility enhancement of PAB by various CDs, including α-CD, β-CD, γ-CD, HP-β-CD and SBE-β-CD was investigated by phase solubility studies. The inclusion complex of PAB/HP-β-CD was prepared by different methods and characterized by differential scanning calorimetry (DSC), powder X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy ((1)H NMR) together with molecular simulation. The results indicated that the solubility of PAB was increased to 15.78mgmL(-1) in the presence of 30% HP-β-CD, which is a 600 fold increase compared with that in pure water. And the chemical stability of PAB in PBS (pH 7.4) can be enhanced. The results of DSC and XRD showed the absence of crystallinity in the PAB/HP-β-CD inclusion complex prepared by the saturated water solution method. The results of (1)H NMR together with molecular simulation indicated the conjugated diene side-chain of PAB was included into the cavity of HP-β-CD, with the free energy of -20.34±4.69kJmol(-1). While the enzymatic degradation site of the carboxyl polar bond is located in the hydrophilic outer of HP-β-CD resulted in no significant difference for the enzymatic degradation rate between PAB and PAB/HP-β-CD complexes in rat plasma. In summary, the PAB/HP-β-CD inclusion complex prepared in this study can greatly improve the solubility and chemical stability of PAB, which will result in the in vivo administration of PAB as a liquid solution. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of 18β-glycyrrhetinic acid and hydroxypropyl γcyclodextrin complex on indomethacin-induced small intestinal injury in mice.

PubMed

Ishida, Tsukasa; Miki, Ikuya; Tanahashi, Toshihito; Yagi, Saori; Kondo, Yasuyuki; Inoue, Jun; Kawauchi, Shoji; Nishiumi, Sin; Yoshida, Masaru; Maeda, Hideko; Tode, Chisato; Takeuchi, Atsuko; Nakayama, Hirokazu; Azuma, Takeshi; Mizuno, Shigeto

2013-08-15

Non-steroidal anti-inflammatory drugs (NSAIDs)-induced small intestinal injury is a serious clinical event with recent advances of diagnostic technologies, but a successful therapeutic method to treat such injuries is still lacking. Licorice, a traditional herbal medicine, and its derivatives have been widely used for the treatment of a variety of diseases due to their extensive biological actions. However, it is unknown whether these derivatives have an effect on NSAIDs-induced small intestinal damage. Previously, the anti-inflammatory effects of three compounds extracted from the licorice root, glycyrrhizin, 18β-glycyrrhetinic acid, and dipotassium glycyrrhizinate, were compared in vitro cell culture. The most prominent inhibitory effect on the tumor necrosis factor-α (TNF-α) production was observed with the administration of 18β-glycyrrhetinic acid as an active metabolite of glycyrrhizin. In this study, a complex compound of 18β-glycyrrhetinic acid and hydroxypropyl γcyclodextrin was examined to improve the oral bioavailability. After administration of this complex to indomethacin treated mice, a significantly high plasma concentration of 18β-glycyrrhetinic acid was detected using the tandem mass spectrometry coupled with the HPLC. Furthermore, the complex form of 18β-glycyrrhetinic acid and hydroxypropyl γcyclodextrin reduced mRNA expressions of TNF-α, interleukin (IL)-1β, and IL-6, which was histologically confirmed in the improvement of indomethacin-induced small intestinal damage. These results suggest that the complex of 18β-glycyrrhetinic acid and hydroxypropyl γcyclodextrin has the potential therapeutic value for preventing the adverse effects of indomethacin-induced small intestinal injury. Copyright © 2013 Elsevier B.V. All rights reserved.

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

NASA Astrophysics Data System (ADS)

Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng

2015-01-01

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 cm2/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

NASA Astrophysics Data System (ADS)

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.

Sources and formation processes of water-soluble dicarboxylic acids, ω-oxocarboxylic acids, α-dicarbonyls, and major ions in summer aerosols from eastern central India

NASA Astrophysics Data System (ADS)

Deshmukh, Dhananjay K.; Kawamura, Kimitaka; Deb, Manas K.; Boreddy, Suresh K. R.

2017-03-01

The sources and formation processes of dicarboxylic acids are still under investigation. Size-segregated aerosol (nine-size) samples collected in the urban site (Raipur: 21.2°N and 82.3°E) in eastern central India during summer of 2013 were measured for water-soluble diacids (C2-C12), ω-oxoacids (ωC2-ωC9), α-dicarbonyls (C2-C3), and inorganic ions to better understand their sources and formation processes. Diacids showed the predominance of oxalic acid (C2), whereas ω-oxoacids showed the predominance of glyoxylic acid (ωC2), and glyoxal (Gly) was a major α-dicarbonyl in all the sizes. Diacids, ω-oxoacids, and α-dicarbonyls as well as SO42

Lack of phosphatidylethanolamine N-methyltransferase in mice does not promote fatty acid oxidation in skeletal muscle.

PubMed

Tasseva, Guergana; van der Veen, Jelske N; Lingrell, Susanne; Jacobs, René L; Vance, Dennis E; Vance, Jean E

2016-02-01

Phosphatidylethanolamine N-methyltransferase (PEMT) converts phosphatidylethanolamine (PE) to phosphatidylcholine (PC) in the liver. Mice lacking PEMT are protected from high-fat diet-induced obesity and insulin resistance, and exhibit increased whole-body energy expenditure and oxygen consumption. Since skeletal muscle is a major site of fatty acid oxidation and energy utilization, we determined if rates of fatty acid oxidation/oxygen consumption in muscle are higher in Pemt(-/-) mice than in Pemt(+/+) mice. Although PEMT is abundant in the liver, PEMT protein and activity were undetectable in four types of skeletal muscle. Moreover, amounts of PC and PE in the skeletal muscle were not altered by PEMT deficiency. Thus, we concluded that any influence of PEMT deficiency on skeletal muscle would be an indirect consequence of lack of PEMT in liver. Neither the in vivo rate of fatty acid uptake by muscle nor the rate of fatty acid oxidation in muscle explants and cultured myocytes depended upon Pemt genotype. Nor did PEMT deficiency increase oxygen consumption or respiratory function in skeletal muscle mitochondria. Thus, the increased whole body oxygen consumption in Pemt(-/-) mice, and resistance of these mice to diet-induced weight gain, are not primarily due to increased capacity of skeletal muscle for utilization of fatty acids as an energy source. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Solubility of aluminum and silica in Spodic horizons as affected by drying and freezing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simonsson, M.; Berggren, D.; Gustafsson, J.P.

The release of toxic Al{sup 3+} is one of the most serious consequences of anthropogenic soil acidification. Therefore, the mechanisms controlling Al solubility have been a topic of intense research for more than a decade. For convenience, soil samples are often dried before storage and experimental use. However, the literature offers examples of drying that results in changes in pH, solubility of organic matter, and dissolution rates of Al. In this study, the authors examined the solubility of Al and Si in fresh soil and in soil that had been dried or deep-frozen. Five Spodosol B horizon soils were subjectedmore » to batch titrations, where portions of each soil were equilibrated with solutions with varying concentrations of acid or base added. Extractions with acid oxalate and Na pyrophosphate indicated the presence of imogolite-type materials (ITM) in three of the soils. In the other two soils most secondary solid-phase Al was associated with humic substances. Deep-freezing did not significantly change pH nor the concentration of Al or Si as compared with fresh soil. Drying, on the other hand, yielded pH increases of up to 0.3 units at a given addition of acid or base, whereas Al{sup 3+} changed only slightly, implying a higher Al solubility in all of the soils. Furthermore, dissolved silica increased by up to 200% after drying, except in a soil that almost completely lacked oxalate-extractable Si. The authors suggest that drying enhanced the dissolution of ITM by disrupting soil organic matter, thus exposing formerly coated mineral surfaces. In the soil where dissolved Si did not change with drying, it has been demonstrated that Al-humus complexes controlled Al solubility. They suggest that fissures in the organic material caused by drying may have exposed formerly occluded binding sites that had a higher Al saturation than had sites at the surface of humus particles.« less

Manganese ore tailing: optimization of acid leaching conditions and recovery of soluble manganese.

PubMed

Santos, Olívia de Souza Heleno; Carvalho, Cornélio de Freitas; Silva, Gilmare Antônia da; Santos, Cláudio Gouvêa Dos

2015-01-01

Manganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (2(3)). The three variables studied were leaching time, concentration of sulfuric acid and sample amount. The three factors screened were shown to be relevant and therefore a Doehlert design was applied to determine the best working conditions for leaching and to build the response surface. By applying the best leaching conditions, the concentrations of 12.80 and 13.64 %w/w of manganese for the global sample and for the fraction -44 + 37 μm, respectively, were found. Microbeads of chitosan were tested for removal of leachate acidity and recovering of soluble manganese. Manganese recovery from the leachate was 95.4%. Upon drying the leachate, a solid containing mostly manganese sulfate was obtained, showing that the proposed optimized method is efficient for manganese recovery from ore tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

PubMed

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.

A soluble NADH-dependent fumarate reductase in the reductive tricarboxylic acid cycle of Hydrogenobacter thermophilus TK-6.

PubMed

Miura, Akane; Kameya, Masafumi; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo

2008-11-01

Fumarate reductase (FRD) is an enzyme that reduces fumarate to succinate. In many organisms, it is bound to the membrane and uses electron donors such as quinol. In this study, an FRD from a thermophilic chemolithoautotrophic bacterium, Hydrogenobacter thermophilus TK-6, was purified and characterized. FRD activity using NADH as an electron donor was not detected in the membrane fraction but was found in the soluble fraction. The purified enzyme was demonstrated to be a novel type of FRD, consisting of five subunits. One subunit showed high sequence identity to the catalytic subunits of known FRDs. Although the genes of typical FRDs are assembled in a cluster, the five genes encoding the H. thermophilus FRD were distant from each other in the genome. Furthermore, phylogenetic analysis showed that the H. thermophilus FRD was located in a distinct position from those of known soluble FRDs. This is the first report of a soluble NADH-dependent FRD in Bacteria and of the purification of a FRD that operates in the reductive tricarboxylic acid cycle.

Precipitation of a monoclonal antibody by soluble tungsten.

PubMed

Bee, Jared S; Nelson, Stephanie A; Freund, Erwin; Carpenter, John F; Randolph, Theodore W

2009-09-01

Tungsten microparticles may be introduced into some pre-filled syringes during the creation of the needle hole. In turn, these microcontaminants may interact with protein therapeutics to produce visible particles. We found that soluble tungsten polyanions formed in acidic buffer below pH 6.0 can precipitate a monoclonal antibody within seconds. Soluble tungsten in pH 5.0 buffer at about 3 ppm was enough to cause precipitation of a mAb formulated at 0.02 mg/mL. The secondary structure of the protein was near-native in the collected precipitate. Our observations are consistent with the coagulation of a monoclonal antibody by tungsten polyanions. Tungsten-induced precipitation should only be a concern for proteins formulated below about pH 6.0 since tungsten polyanions are not formed at higher pHs. We speculate that the heterogenous nature of particle contamination within the poorly mixed syringe tip volume could mean that a specification for tungsten contamination based on the entire syringe volume is not appropriate. The potential potency of tungsten metal contamination is highlighted by the small number of particles that would be required to generate soluble tungsten levels needed to coagulate this antibody at pH 5.0.

Precipitation of a Monoclonal Antibody by Soluble Tungsten

PubMed Central

Bee, Jared S.; Nelson, Stephanie A.; Freund, Erwin; Carpenter, John F.; Randolph, Theodore W.

2009-01-01

Tungsten microparticles may be introduced into some pre-filled syringes during the creation of the needle hole. In turn, these microcontaminants may interact with protein therapeutics to produce visible particles. We found that soluble tungsten polyanions formed in acidic buffer below pH 6.0 can precipitate a monoclonal antibody within seconds. Soluble tungsten in pH 5.0 buffer at about 3 ppm was enough to cause precipitation of a mAb formulated at 0.02 mg/mL. The secondary structure of the protein was near-native in the collected precipitate. Our observations are consistent with the coagulation of a monoclonal antibody by tungsten polyanions. Tungsten-induced precipitation should only be a concern for proteins formulated below about pH 6.0 since tungsten polyanions are not formed at higher pHs. We speculate that the heterogenous nature of particle contamination within the poorly mixed syringe tip volume could mean that a specification for tungsten contamination based on the entire syringe volume is not appropriate. The potential potency of tungsten metal contamination is highlighted by the small number of particles that would be required to generate soluble tungsten levels needed to coagulate this antibody at pH 5.0. PMID:19230018

Determination of water-soluble vitamins using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts.

PubMed

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.

PubMed

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.

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Wei; Han, Shijiao; Huang, Wei

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 inmore » 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.« less

Poly(lactic acid) nanoparticles coated with combined WGA and water-soluble chitosan for mucosal delivery of β-galactosidase.

PubMed

Sheng, Yan; He, Hongjun; Zou, Hui

2014-08-01

A combinatorial design, physical adsorption of water-soluble chitosan (WSC) to particle surface and covalent conjugation of wheat germ agglutinin (WGA) to WSC, was applied to surface modification of poly(lactic acid) nanoparticles (NPs) for targeted delivery of β-galactosidase to the intestinal mucosa. All the surface-engineered NPs in the size range of 500-600 nm were prepared by a w/o/w solvent diffusion/evaporation technique. β-Galactosidase encapsulated in these NPs was well protected from external proteolysis and exerted high hydrolytic activity on the permeable lactose. The presence of WSC coating, whether alone or with WGA, highly improved the suspension stability of NPs and tailored the particle surface positively charged. In comparison to NPs modified with WGA or WSC alone, the synergistic action of WGA and WSC greatly enhanced the NP-mucin interactions in vitro. The highest amount of NPs was found in the small intestine at 24 h after oral administration in rats. Notably, calculated half-life of WGA-WSC-NPs in the small intestine was 6.72 h, resulting in 2.1- and 4.3-fold increase when compared to WGA-polyvinylalcohol (PVA)-NPs and WSC-NPs, much longer than that of control PVA-NPs (6.9-fold). These results suggest that NPs with the combined WGA and WSC coating represent promising candidates for efficient mucosal drug delivery as well as biomimetic treatment of lactose intolerance.

The Changes in Color, Soluble Sugars, Organic Acids, Anthocyanins and Aroma Components in "Starkrimson" during the Ripening Period in China.

PubMed

Liu, Yulian; Chen, Nianlai; Ma, Zonghuan; Che, Fei; Mao, Juan; Chen, Baihong

2016-06-22

"Starkrimson" is a traditional apple cultivar that was developed a long time ago and was widely cultivated in the arid region of the northern Wei River of China. However, little information regarding the quality characteristics of "Starkrimson" fruit has been reported in this area. To elucidate these characteristics, the color, soluble sugars, organic acids, anthocyanins and aroma components were measured during the ripening period through the use of high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The results indicated that the changes in anthocyanin contents took place later than the changes in the Commission International Eclairage (CIE) parameters. Meanwhile, cyanidin 3-galactoside (cy3-gal), fructose, sucrose, glucose and malic acid were the primary organic compounds, and 1-butanol-2-methyl-acetate, 2-hexenal and 1-hexanol were the most abundant aroma components in the skin. Furthermore, rapidly changing soluble sugars and organic acid synchronization took place in the early ripening period, while rapidly changing aroma components occurred later, on the basis of fresh weight. This result suggested that the production of aroma components might be a useful index of apple maturity.

High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountaintop aerosols over the North China Plain during wheat burning season

NASA Astrophysics Data System (ADS)

Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

2013-08-01

Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N, 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low-molecular-weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Molecular distributions of dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acids, were also detected together with aromatic diacids (phthalic, isophthalic and terephthalic acids). ω-oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (>6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June, showing a maximum on 7 June, and then significantly decreased during the period 8-11 June, when the wind direction shifted from southerly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of

[Impacts of multicomponent environment on solubility of puerarin in biopharmaceutics classification system of Chinese materia medica].

PubMed

Hou, Cheng-Bo; Wang, Guo-Peng; Zhang, Qiang; Yang, Wen-Ning; Lv, Bei-Ran; Wei, Li; Dong, Ling

2014-12-01

To illustrate the solubility involved in biopharmaceutics classification system of Chinese materia medica (CMMBCS) , the influences of artificial multicomponent environment on solubility were investigated in this study. Mathematical model was built to describe the variation trend of their influence on the solubility of puerarin. Carried out with progressive levels, single component environment: baicalin, berberine and glycyrrhizic acid; double-component environment: baicalin and glycyrrhizic acid, baicalin and berberine and glycyrrhizic acid and berberine; and treble-component environment: baicalin, berberin, glycyrrhizic acid were used to describe the variation tendency of their influences on the solubility of puerarin, respectively. And then, the mathematical regression equation model was established to characterize the solubility of puerarin under multicomponent environment.

Characterization of a thermally imidized soluble polyimide film

NASA Technical Reports Server (NTRS)

Young, Philip R.; Davis, Judith R. J.; Chang, A. C.; Richardson, John N.

1989-01-01

A soluble aromatic poly(amic acid) film was converted to a soluble polyimide by staging at 25 deg intervals to 325 C and characterized at each interval by several analytical methods. The behavior observed was consistent with an interpretation that a reduction occurred in molecular weight of the poly(amic acid) during the initial stages of cure before the ultimate molecular weight was achieved as a polyimide. This interpretation was supported by the results of solution viscosity, gel permeation chromatography, low angle laser light scattering photometry and infrared spectroscopy analysis. The results serve to increase the fundamental understanding of how polyimides are thermally formed from poly(amic acids).

Solubility Limits of Dibutyl Phosphoric Acid in Uranium Solutions at SRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 {tilde 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 atmore » 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{sub 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{sub 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

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

PubMed

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.

Hygroscopic Properties of Internally Mixed Particles Composed of NaCl and Water-Soluble Organic Acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei V.

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 and X-ray elemental microanalysis.Hygroscopic properties of inte rnally mixed NaCl and organic acid particles were distinctly differentmore » 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 Na-malonate and Na-glutarate salts resulted by HCl evaporation from dehydrating particles.« less

Canine intestinal contents vs. simulated media for the assessment of solubility of two weak bases in the human small intestinal contents.

PubMed

Kalantzi, Lida; Persson, Eva; Polentarutti, Britta; Abrahamsson, Bertil; Goumas, Konstantinos; Dressman, Jennifer B; Reppas, Christos

2006-06-01

This study was conducted to assess the relative usefulness of canine intestinal contents and simulated media in the prediction of solubility of two weak bases (dipyridamole and ketoconazole) in fasted and fed human intestinal aspirates that were collected under conditions simulating those in bioavailability/bioequivalence studies. After administration of 250 mL of water or 500 mL of Ensure plus [both containing 10 mg/mL polyethylene glycol (PEG) 4000 as nonabsorbable marker], intestinal aspirates were collected from the fourth part of the duodenum of 12 healthy adults and from the mid-jejunum of four Labradors. Pooled samples were analyzed for PEG, pH, buffer capacity, osmolality, surface tension, pepsin, total carbohydrates, total protein content, bile salts, phospholipids, and neutral lipids. The shake-flask method was used to measure the solubility of dipyridamole and ketoconazole in pooled human and canine intestinal contents and in fasted-state-simulating intestinal fluid (FaSSIF) and fed-state-simulating intestinal fluid (FeSSIF) containing various bile salts and pH-buffering agents. For both compounds, solubility in canine contents may be predictive of human intralumenal solubility in the fasting state but not in the fed state. The poor agreement of results in canine and human aspirates can be attributed to the higher bile salt content in canine bile. Solubility in FaSSIF containing a mixture of bile salts from crude bile predicted satisfactorily the intralumenal solubility of both drugs in the fasted state in humans. Solubility in FeSSIF, regardless of the identity of bile salts or of the buffering species, deviated from intralumenal values in the fed human aspirates by up to 40%. This was attributed to the lack of lipolytic products in FeSSIF, the higher bile salt content of FeSSIF, and the lower pH of FeSSIF. FaSSIF containing a mixture of bile salts from crude bile, and FeSSIF containing lipolytic products and, perhaps, having lower bile salt content but

Crystallization of a salt of a weak organic acid and base: solubility relations, supersaturation control and polymorphic behavior.

PubMed

Jones, H P; Davey, R J; Cox, B G

2005-03-24

Control of crystallization processes for organic salts is of importance to the pharmaceutical industry as many active pharmaceutical materials are marketed as salts. In this study, a method for estimating the solubility product of a salt of a weak acid and weak base from measured pH-solubility data is described for the first time. This allows calculation of the supersaturation of solutions at known pH. Ethylenediammonium 3,5-dinitrobenzoate is a polymorphic organic salt. A detailed study of the effects of pH, supersaturation, and temperature of crystallization on the physical properties of this salt shows that the desired polymorph may be produced by appropriate selection of the pH and supersaturation of crystallization. Crystal morphology is also controlled by these crystallization conditions.

Modeling solubility and acid-base properties of some amino acids in aqueous NaCl and (CH3)4NCl aqueous solutions at different ionic strengths and temperatures.

PubMed

Bretti, Clemente; Giuffrè, Ottavia; Lando, Gabriele; Sammartano, Silvio

2016-01-01

New potentiometric experiments have been performed in NaCl and in (CH3)4NCl media, to determine the protonation constants, the protonation enthalpy changes and the solubility of six natural α-amino acids, namely Glycine (Gly), Alanine (Ala), Valine (Val), Leucine (Leu), Serine (Ser) and Phenylalanine (Phe). The aim of the work is the rationalization of the protonation thermodynamics (log [Formula: see text], solubility and [Formula: see text]) in NaCl, determining recommended, tentative or provisional values in selected experimental conditions and to report, for the first time, data in a weak interacting medium, as (CH3)4NCl. Literature data analysis was performed selecting the most reliable values, analyzed together with new data here reported. Significant trends and similarities were observed in the behavior of the six amino acids, and in some cases it was possible to determine common parameters for the ionic strength and temperature dependence. In general, the first protonation step, relative to the amino group, is significantly exothermic (average value is [Formula: see text] = -44.5 ± 0.4 kJ mol(-1) at infinite dilution and T = 298.15 K), and the second, relative to the carboxylate group, is fairly close to zero ([Formula: see text] = -2.5 ± 1.6, same conditions). In both cases, the main contribution to the proton binding reaction is mainly entropic in nature. For phenylalanine and leucine, solubility measurements at different concentrations of supporting electrolyte allowed to determine total and specific solubility values, then used to obtain the Setschenow and the activity coefficients of all the species involved in the protonation equilibria. The values of the first protonation constant in (CH3)4NCl are lower than the corresponding values in NaCl, due to the weak interaction between the deprotonated amino group and (CH3)4N(+). In this light, differences between the protonation functions in NaCl and (CH3)4NCl were used for the quantification

High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountain aerosols over the North China Plain during wheat burning season

NASA Astrophysics Data System (ADS)

Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

2013-02-01

Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N; 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low molecular weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acid, were also detected together with aromatic diacids (phthalic, iso-phthalic and tere-phthalic acids). ω-Oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (> 6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June showing a maximum on 7 June and then significantly decreased during 8-11 June when the wind direction shifted from northeasterly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning products of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of volatile and semi

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

PubMed

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.

A Soluble NADH-Dependent Fumarate Reductase in the Reductive Tricarboxylic Acid Cycle of Hydrogenobacter thermophilus TK-6▿

PubMed Central

Miura, Akane; Kameya, Masafumi; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo

2008-01-01

Fumarate reductase (FRD) is an enzyme that reduces fumarate to succinate. In many organisms, it is bound to the membrane and uses electron donors such as quinol. In this study, an FRD from a thermophilic chemolithoautotrophic bacterium, Hydrogenobacter thermophilus TK-6, was purified and characterized. FRD activity using NADH as an electron donor was not detected in the membrane fraction but was found in the soluble fraction. The purified enzyme was demonstrated to be a novel type of FRD, consisting of five subunits. One subunit showed high sequence identity to the catalytic subunits of known FRDs. Although the genes of typical FRDs are assembled in a cluster, the five genes encoding the H. thermophilus FRD were distant from each other in the genome. Furthermore, phylogenetic analysis showed that the H. thermophilus FRD was located in a distinct position from those of known soluble FRDs. This is the first report of a soluble NADH-dependent FRD in Bacteria and of the purification of a FRD that operates in the reductive tricarboxylic acid cycle. PMID:18757546

Gallic acid/hydroxypropyl-β-cyclodextrin complex: Improving solubility for application on in vitro/ in vivo Candida albicans biofilms

PubMed Central

Teodoro, Guilherme Rodrigues; Salvador, Marcos José; Koga-Ito, Cristiane Yumi

2017-01-01

The aim of this study was to increase the solubility of gallic acid (GA) for the treatment of Candida albicans biofilm, which is very difficult to treat and requires high drug concentrations. Cyclodextrins (CDs) were used for this purpose. Complexes were evaluated by phase-solubility studies, prepared by spray drying and characterized by drug loading, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The complexes were tested on C. albicans biofilm using in vitro and in vivo models. HPβCD formed soluble inclusion complexes with GA. The percentage of GA in GA/HPβCD was 10.8 ± 0.01%. The SEM and DSC analyses confirmed the formation of inclusion complexes. GA/HPβCD maintained the antimicrobial activity of the pure GA. GA/HPβCD was effective on C. albicans biofilms of 24 and 48h. The in vivo results showed an anti-inflammatory activity of GA/HPβCD with no difference in invading hypha counting among the groups. This study encourages the development of new antifungal agents. PMID:28700692

Utilization of Condensed Distillers Solubles as Nutrient Supplement for Production of Nisin and Lactic Acid from Whey

NASA Astrophysics Data System (ADS)

Liu, Chuanbin; Hu, Bo; Chen, Shulin; Glass, Richard W.

The major challenge associated with the rapid growth of the ethanol industry is the usage of the coproducts, i.e., condensed distillers solubles (CDS) and distillers dried grains, which are currently sold as animal feed supplements. As the growth of the livestock industries remains flat, alternative usage of these coproducts is urgently needed. CDS is obtained after the removal of ethanol by distillation from the yeast fermentation of a grain or a grain mixture by condensing the thin stillage fraction to semisolid. In this work, CDS was first characterized and yeast biomass was proven to be the major component of CDS. CDS contained 7.50% crude protein but with only 42% of that protein being water soluble. Then, CDS was applied as a nutrient supplement for simultaneous production of nisin and lactic acid by Lactococcus lactis subsp. lactis (ATCC 11454). Although CDS was able to support bacteria growth and nisin production, a strong inhibition was observed when CDS was overdosed. This may be caused by the existence of the major ethanol fermentation byproducts, especially lactate and acetate, in CDS. In the final step, the CDS based medium composition for nisin and lactic acid production was optimized using response surface methodology.

Core-shell nanofibers of curcumin/cyclodextrin inclusion complex and polylactic acid: Enhanced water solubility and slow release of curcumin.

PubMed

Aytac, Zeynep; Uyar, Tamer

2017-02-25

Core-shell nanofibers were designed via electrospinning using inclusion complex (IC) of model hydrophobic drug (curcumin, CUR) with cyclodextrin (CD) in the core and polymer (polylactic acid, PLA) in the shell (cCUR/HPβCD-IC-sPLA-NF). CD-IC of CUR and HPβCD was formed at 1:2 molar ratio. The successful formation of core-shell nanofibers was revealed by TEM and CLSM images. cCUR/HPβCD-IC-sPLA-NF released CUR slowly but much more in total than PLA-CUR-NF at pH 1 and pH 7.4 due to the restriction of CUR in the core of nanofibers and solubility improvement shown in phase solubility diagram, respectively. Improved antioxidant activity of cCUR/HPβCD-IC-sPLA-NF in methanol:water (1:1) is related with the solubility enhancement achieved in water based system. The slow reaction of cCUR/HPβCD-IC-sPLA-NF in methanol is associated with the shell inhibiting the quick release of CUR. On the other hand, cCUR/HPβCD-IC-sPLA-NF exhibited slightly higher rate of antioxidant activity than PLA-CUR-NF in methanol:water (1:1) owing to the enhanced solubility. To conclude, slow release of CUR was achieved by core-shell nanofiber structure and inclusion complexation of CUR with HPβCD provides high solubility. Briefly, electrospinning of core-shell nanofibers with CD-IC core could offer slow release of drugs as well as solubility enhancement for hydrophobic drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

NALDB: nucleic acid ligand database for small molecules targeting nucleic acid.

PubMed

Kumar Mishra, Subodh; Kumar, Amit

2016-01-01

Nucleic acid ligand database (NALDB) is a unique database that provides detailed information about the experimental data of small molecules that were reported to target several types of nucleic acid structures. NALDB is the first ligand database that contains ligand information for all type of nucleic acid. NALDB contains more than 3500 ligand entries with detailed pharmacokinetic and pharmacodynamic information such as target name, target sequence, ligand 2D/3D structure, SMILES, molecular formula, molecular weight, net-formal charge, AlogP, number of rings, number of hydrogen bond donor and acceptor, potential energy along with their Ki, Kd, IC50 values. All these details at single platform would be helpful for the development and betterment of novel ligands targeting nucleic acids that could serve as a potential target in different diseases including cancers and neurological disorders. With maximum 255 conformers for each ligand entry, our database is a multi-conformer database and can facilitate the virtual screening process. NALDB provides powerful web-based search tools that make database searching efficient and simplified using option for text as well as for structure query. NALDB also provides multi-dimensional advanced search tool which can screen the database molecules on the basis of molecular properties of ligand provided by database users. A 3D structure visualization tool has also been included for 3D structure representation of ligands. NALDB offers an inclusive pharmacological information and the structurally flexible set of small molecules with their three-dimensional conformers that can accelerate the virtual screening and other modeling processes and eventually complement the nucleic acid-based drug discovery research. NALDB can be routinely updated and freely available on bsbe.iiti.ac.in/bsbe/naldb/HOME.php. Database URL: http://bsbe.iiti.ac.in/bsbe/naldb/HOME.php. © The Author(s) 2016. Published by Oxford University Press.

NALDB: nucleic acid ligand database for small molecules targeting nucleic acid

PubMed Central

Kumar Mishra, Subodh; Kumar, Amit

2016-01-01

Nucleic acid ligand database (NALDB) is a unique database that provides detailed information about the experimental data of small molecules that were reported to target several types of nucleic acid structures. NALDB is the first ligand database that contains ligand information for all type of nucleic acid. NALDB contains more than 3500 ligand entries with detailed pharmacokinetic and pharmacodynamic information such as target name, target sequence, ligand 2D/3D structure, SMILES, molecular formula, molecular weight, net-formal charge, AlogP, number of rings, number of hydrogen bond donor and acceptor, potential energy along with their Ki, Kd, IC50 values. All these details at single platform would be helpful for the development and betterment of novel ligands targeting nucleic acids that could serve as a potential target in different diseases including cancers and neurological disorders. With maximum 255 conformers for each ligand entry, our database is a multi-conformer database and can facilitate the virtual screening process. NALDB provides powerful web-based search tools that make database searching efficient and simplified using option for text as well as for structure query. NALDB also provides multi-dimensional advanced search tool which can screen the database molecules on the basis of molecular properties of ligand provided by database users. A 3D structure visualization tool has also been included for 3D structure representation of ligands. NALDB offers an inclusive pharmacological information and the structurally flexible set of small molecules with their three-dimensional conformers that can accelerate the virtual screening and other modeling processes and eventually complement the nucleic acid-based drug discovery research. NALDB can be routinely updated and freely available on bsbe.iiti.ac.in/bsbe/naldb/HOME.php. Database URL: http://bsbe.iiti.ac.in/bsbe/naldb/HOME.php PMID:26896846

Glycyrrhetinic Acid-Poly(ethylene glycol)-glycyrrhetinic Acid Tri-Block Conjugates Based Self-Assembled Micelles for Hepatic Targeted Delivery of Poorly Water Soluble Drug

PubMed Central

Xu, Ting; Liu, Chi; Chen, Can; Song, Xiangrong; Zheng, Yu

2013-01-01

The triblock 18β-glycyrrhetinic acid-poly(ethylene glycol)-18β-glycyrrhetinic acid conjugates (GA-PEG-GA) based self-assembled micelles were synthesized and characterized by FTIR, NMR, transmission electron microscopy, and particle size analysis. The GA-PEG-GA conjugates having the critical micelle concentration of 6 × 10−5 M were used to form nanosized micelles, with mean diameters of 159.21 ± 2.2 nm, and then paclitaxel (PTX) was incorporated into GA-PEG-GA micelles by self-assembly method. The physicochemical properties of the PTX loaded GA-PEG-GA micelles were evaluated including in vitro cellular uptake, cytotoxicity, drug release profile, and in vivo tissue distribution. The results demonstrate that the GA-PEG-GA micelles had low cytotoxicity and good ability of selectively delivering drug to hepatic cells in vitro and in vivo by the targeting moiety glycyrrhetinic acid. In conclusion, the GA-PEG-GA conjugates have potential medical applications for targeted delivery of poor soluble drug delivery. PMID:24376388

Cerebral asymmetry and behavioral lateralization in rats chronically lacking n-3 polyunsaturated fatty acids.

PubMed

Vancassel, Sylvie; Aïd, Sabah; Pifferi, Fabien; Morice, Elise; Nosten-Bertrand, Marika; Chalon, Sylvie; Lavialle, Monique

2005-11-15

Anatomic and functional brain lateralization underlies hemisphere specialization for cognitive and motor control, and deviations from the normal patterns of asymmetry appear to be related to behavioral deficits. Studies on n-3 polyunsaturated fatty acid (PUFA) deficiency and behavioral impairments led us to postulate that a chronic lack of n-3 PUFA can lead to changes in lateralized behavior by affecting structural or neurochemical patterns of asymmetry in motor-related brain structures. We compared the effects of a chronic n-3 PUFA deficient diet with a balanced diet on membrane phospholipid fatty acids composition and immunolabeling of choline acetyltransferase (ChAt), as a marker of cholinergic neurons, in left and right striatum of rats. Lateral motor behavior was assessed by rotation and paw preference. Control rats had an asymmetric PUFA distribution with a right behavioral preference, whereas ChAt density was symmetrical. In deficient rats, the cholinergic neuron density was 30% lower on the right side, associated with a loss of PUFA asymmetry and behavior laterality. They present higher rotation behavior, and significantly more of them failed the handedness test. These results indicate that a lack of n-3 PUFA is linked with a lateral behavior deficit, possibly leading to cognitive disturbances.

Fat-soluble vitamins and plasma and erythrocyte membrane fatty acids in chylothorax pediatric patients receiving a medium-chain triglyceride-rich diet.

PubMed

Densupsoontorn, Narumon; Jirapinyo, Pipop; Tirapongporn, Hathaichanok; Wongarn, Renu; Chotipanang, Kwanjai; Phuangphan, Phakkanan; Chongviriyaphan, Nalinee

2014-11-01

Post-operative chylothorax can be cured by a medium-chain triglyceride (MCT)-rich diet. However, there is concern that an MCT-rich diet results in clinical and biochemical deficiencies in fat-soluble vitamins and fatty acids. We compared fat-soluble vitamins status and fatty acids status before and after administration of an MCT-rich diet. Nine children with congenital heart disease developed chylothorax after cardiac surgery. Blood samples were drawn from each subject twice, first prior to administration of an MCT-rich diet and secondly when the chylothorax was clinically cured and the MCT diet discontinued. Both blood samples were analyzed for retinol and 25-hydroxy vitamin D concentrations, the ratio of α-tocopherol to total lipids (α-TE/TL), coagulogram, and the fatty acid composition in plasma and erythrocyte membrane phospholipids. In spite of a decrease in the α-TE/TL ratio (3.78 ± 0.89 vs 2.36 ± 0.44 mg/g, p<0.05), this decrease did not reach the deficiency cut-off level. Linoleic acid in both plasma and erythrocyte membrane lipids decreased significantly (25.25 ± 8.06 vs 14.25 ± 2.88%, and 11.19 ± 2.15 vs 6.89 ± 2.45%, respectively). Administration of an MCT-rich diet for treatment of postoperative chylothorax caused a reduction in vitamin E status and linoleic acid, but without any symptoms of deficiency.

Bioinspired co-crystals of Imatinib providing enhanced kinetic solubility.

PubMed

Reggane, Maude; Wiest, Johannes; Saedtler, Marco; Harlacher, Cornelius; Gutmann, Marcus; Zottnick, Sven H; Piechon, Philippe; Dix, Ina; Müller-Buschbaum, Klaus; Holzgrabe, Ulrike; Meinel, Lorenz; Galli, Bruno

2018-05-04

Realizing the full potential of co-crystals enhanced kinetic solubility demands a comprehensive understanding of the mechanisms of dissolution, phase conversion, nucleation and crystal growth, and of the complex interplay between the active pharmaceutical ingredient (API), the coformer and co-existing forms in aqueous media. One blueprint provided by nature to keep poorly water-soluble bases in solution is the complexation with phenolic acids. Consequently, we followed a bioinspired strategy for the engineering of co-crystals of a poorly water-soluble molecule - Imatinib - with a phenolic acid, syringic acid (SYA). The dynamics of dissolution and solution-mediated phase transformations were monitored by Nuclear Magnetic Resonance (NMR) spectroscopy, providing mechanistic insights into the 60 fold-increased long lasting concentrations achieved by the syringate co-crystals as compared to Imatinib base and Imatinib mesylate. This lasting effect was linked to SYA's ability to delay the formation and nucleation of Imatinib hydrate - the thermodynamically stable form in aqueous media - through a metastable association of SYA with Imatinib in solution. Results from permeability studies evidenced that SYA did not impact Imatinib's permeability across membranes while suggesting improved bioavailability through higher kinetic solubility at the biological barriers. These results reflect that some degree of hydrophobicity of the coformer might be key to extend the kinetic solubility of co-crystals with hydrophobic APIs. Understanding how kinetic supersaturation can be shaped by the selection of an interactive coformer may help achieving the needed performance of new forms of poorly water-soluble, slowly dissolving APIs. Copyright © 2018. Published by Elsevier B.V.

Senior high school students’ need analysis of Three-Tier Multiple Choice (3TMC) diagnostic test about acid-base and solubility equilibrium

NASA Astrophysics Data System (ADS)

Ardiansah; Masykuri, M.; Rahardjo, S. B.

2018-05-01

Students’ conceptual understanding is the most important comprehension to obtain related comprehension. However, they held their own conception. With this need analysis, we will elicit student need of 3TMC diagnostic test to measure students’ conception about acid-base and solubility equilibrium. The research done by a mixed method using questionnaire analysis based on descriptive of quantitative and qualitative. The research subject was 96 students from 4 senior high schools and 4 chemistry teachers chosen by random sampling technique. Data gathering used a questionnaire with 10 questions for student and 28 questions for teachers. The results showed that 97% of students stated that the development this instrument is needed. In addition, there were several problems obtained in this questionnaire include learning activity, teacher’s test and guessing. In conclusion, this is necessary to develop the 3TMC instrument that can diagnose and measure the student’s conception in acid-base and solubility equilibrium.

Biodegradable fibre scaffolds incorporating water-soluble drugs and proteins.

PubMed

Ma, J; Meng, J; Simonet, M; Stingelin, N; Peijs, T; Sukhorukov, G B

2015-07-01

A new type of biodegradable drug-loaded fibre scaffold has been successfully produced for the benefit of water-soluble drugs and proteins. Model drug loaded calcium carbonate (CaCO3) microparticles incorporated into poly(lactic acid-co-glycolic acid) (PLGA) fibres were manufactured by co-precipitation of CaCO3 and the drug molecules, followed by electrospinning of a suspension of such drug-loaded microparticles in a PLGA solution. Rhodamine 6G and bovine serum albumin were used as model drugs for our release study, representing small bioactive molecules and protein, respectively. A bead and string structure of fibres was achieved. The drug release was investigated with different drug loadings and in different pH release mediums. Results showed that a slow and sustained drug release was achieved in 40 days and the CaCO3 microparticles used as the second barrier restrained the initial burst release.

Effects of excess pantothenic acid administration on the other water-soluble vitamin metabolisms in rats.

PubMed

Shibata, Katsumi; Takahashi, Chisato; Fukuwatari, Tsutomu; Sasaki, Ryuzo

2005-12-01

To acquire the data concerning the tolerable upper intake level which prevents health problems from an excessive intake of pantothenic acid, an animal experiment was done. Rats of the Wistar strain (male, 3 wk old) were fed on a diet which contains 0%, 0.0016% (control group), 1%, or 3% calcium pantothenate for 29 d. The amount of weight increase, the food intake, and the organ weights were measured, as well as the pantothenic acid contents in urine, the liver and blood. Moreover, to learn the influence of excessive pantothenic acid on other water-soluble vitamin metabolism, thiamin, riboflavin, a vitamin B6 catabolite, the niacin catabolites, and ascorbic acid in urine were measured. As for the 3% addition group, enlargement of the testis, diarrhea, and hair damage were observed, and the amount of weight increase and the food intake were less than those of the control group. However, abnormality was not seen in the 1% addition group. The amount of pantothenic acid in urine, the liver, and blood showed a high correlation with intake level of pantothenic acid. It was only for 4-pyridoxic acid, a vitamin B6 catabolite, in urine that a remarkable difference was observed against the control group. Moreover, the (2-Py+4-Py)/MNA excretion ratio for these metabolites of the nicotinamide also indicated a low value in the 3% pantothenic acid group. As for the calcium pantothenate, it was found that the 3% level in the diet was the lowest-observed-adverse-effect-level (LOAEL) and the 1% level was the no-observed-adverse-effect-level (NOAEL).

Effect of enzymatic treatment of extracted sunflower proteins on solubility, amino acid composition, and surface activity.

PubMed

Conde, José Miñones; Escobar, María del Mar Yust; Pedroche Jiménez, Justo J; Rodríguez, Francisco Millán; Rodríguez Patino, Juan M

2005-10-05

Industrial proteins from agriculture of either animal or vegetable origin, including their peptide derivatives, are of great importance, from the qualitative and quantitative point of view, in food formulations (emulsions and foams). A fundamental understanding of the physical, chemical, and functional properties of these proteins is essential if the performance of proteins in foods is to be improved and if underutilized proteins, such as plant proteins (and their hydrolysates and peptides derivatives), are to be increasingly used in traditional and new processed food products (safe, high-quality, health foods with good nutritional value). In this contribution we have determined the main physicochemical characteristics (solubility, composition, and analysis of amino acids) of a sunflower protein isolate (SPI) and its hydrolysates with low (5.62%), medium (23.5%), and high (46.3%) degrees of hydrolysis. The hydrolysates were obtained by enzymatic treatment with Alcalase 2.4 L for DH 5.62 and 23.5% and with Alcalase 2.4 L and Flavorzyme 1000 MG sequentially for DH 46.3%. The protein concentration dependence on surface pressure (surface pressure isotherm), a measure of the surface activity of the products (SPI and its hydrolysates), was obtained by tensiometry. We have observed that the degree of hydrolysis has an effect on solubility, composition, and content of the amino acids of the SPI and its hydrolysates. The superficial activity and the adsorption efficiency were also affected by the degree of hydrolysis.

Photoaddition of N-substituted piperazines to C60: an efficient approach to the synthesis of water-soluble fullerene derivatives.

PubMed

Troshina, Olesya A; Troshin, Pavel A; Peregudov, Alexander S; Kozlovski, Viacheslav I; Lyubovskaya, Rimma N

2006-07-17

An oxidative radical photoaddition of mono N-substituted piperazines to [60]fullerene was systematically investigated. Reactions of C60 with piperazines bearing bulky electron-withdrawing groups (2-pyridyl, 2-pyrimidinyl) were found to be the most selective and yielded C60(amine)4O as major products along with small amounts of C60(amine)2. In contrast, interactions of fullerene with N-methylpiperazine and N-(tert-butoxycarbonyl)piperazine were found to have low selectivity due to different side reactions. Tetraaminofullerene derivative C60(N-(2-pyridyl)piperazine)4O was found to react readily with organic and inorganic acids to yield highly water-soluble salts (solubility approximately 150 mg mL(-1)). In contrast, C60(N-(2-pyrimidinyl)piperazine)4O undergoes hydrolysis under the same conditions and results in a complex mixture of compounds with an average composition of C60(N-(2-pyrimidinyl)piperazine)2(OH)2O. Radical photoaddition of N-(2-pyridyl)piperazine to fullerene derivatives can be used as a facile route for their transformation into water-soluble compounds. Two model fullerene cycloadducts (a methanofullerene and a pyrrolidinofullerene) were easily converted into mixtures of regioisomers of A=C60(N-(2-pyridyl)piperazine)4O (A=cyclic addend) that give highly water-soluble salts under acid treatment.

Soluble Dietary Fibers Can Protect the Small Intestinal Mucosa Without Affecting the Anti-inflammatory Effect of Indomethacin in Adjuvant-Induced Arthritis Rats.

PubMed

Satoh, Hiroshi; Matsumoto, Hiroki; Hirakawa, Tomoe; Wada, Naoki

2016-01-01

How to prevent the small intestinal damage induced by NSAIDs is an urgent issue to be resolved. In the present study, we examined the effects of soluble dietary fibers on both anti-inflammatory and ulcerogenic effects of indomethacin in arthritic rats. Male Wistar rats weighing 180-220 g were used. Arthritis was induced by injecting Freund's complete adjuvant (killed M. tuberculosis) into the plantar region of the right hindpaw. The animals were fed a regular powder diet for rats or a diet supplemented with soluble dietary fibers such as pectin or guar gum. Indomethacin was administered once a day for 3 days starting 14 days after the adjuvant injection, when marked arthritis was observed. The volumes of the hindpaw were measured before and after indomethacin treatment to evaluate the effect of indomethacin on edema. The lesions in the small intestine were examined 24 h after the final dosing of indomethacin. Hindpaw volume was increased about 3 times 14 days after injection of the adjuvant. Indomethacin (3-10 mg/kg, p.o.) decreased hindpaw volume dose-dependently, but caused severe lesions in the small intestine at doses of 6 and 10 mg/kg. The addition of pectin (1-10 %) or guar gum (10 %) to the diet markedly decreased the lesion formation without affecting the anti-edema action of indomethacin. The same effects of pectin were observed when indomethacin was administered subcutaneously. It is suggested that soluble dietary fibers can prevent intestinal damage induced by NSAIDs without affecting the anti-inflammatory effect of these agents.

Electrospinning of calcium phosphate-poly (d,l-lactic acid) nanofibers for sustained release of water-soluble drug and fast mineralization

PubMed Central

Fu, Qi-Wei; Zi, Yun-Peng; Xu, Wei; Zhou, Rong; Cai, Zhu-Yun; Zheng, Wei-Jie; Chen, Feng; Qian, Qi-Rong

2016-01-01

Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP) nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(d,l-lactic acid) (ACP-PLA) nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63) cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due to the high biocompatibility, sustained drug release, and fast mineralization, the as-prepared composite nanofibers may have potential applications in water-soluble drug loading and release for tissue engineering. PMID:27785016

δ-Conotoxins synthesized using an acid-cleavable solubility tag approach reveal key structural determinants for NaV subtype selectivity.

PubMed

Peigneur, Steve; Paolini-Bertrand, Marianne; Gaertner, Hubert; Biass, Daniel; Violette, Aude; Stöcklin, Reto; Favreau, Philippe; Tytgat, Jan; Hartley, Oliver

2014-12-19

Conotoxins are venom peptides from cone snails with multiple disulfide bridges that provide a rigid structural scaffold. Typically acting on ion channels implicated in neurotransmission, conotoxins are of interest both as tools for pharmacological studies and as potential new medicines. δ-Conotoxins act by inhibiting inactivation of voltage-gated sodium channels (Nav). Their pharmacology has not been extensively studied because their highly hydrophobic character makes them difficult targets for chemical synthesis. Here we adopted an acid-cleavable solubility tag strategy that facilitated synthesis, purification, and directed disulfide bridge formation. Using this approach we readily produced three native δ-conotoxins from Conus consors plus two rationally designed hybrid peptides. We observed striking differences in Nav subtype selectivity across this group of compounds, which differ in primary structure at only three positions: 12, 23, and 25. Our results provide new insights into the structure-activity relationships underlying the Nav subtype selectivity of δ-conotoxins. Use of the acid-cleavable solubility tag strategy should facilitate synthesis of other hydrophobic peptides with complex disulfide bridge patterns. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Lack of small-scale clustering in 21-cm intensity maps crossed with 2dF galaxy densities at z ~ 0.08

NASA Astrophysics Data System (ADS)

Anderson, Christopher; Luciw, Nicholas; Li, Yi-Chao; Kuo, Cheng-Yu; Yadav, Jaswant; Masui, Kiyoshi; Chang, Tzu-Ching; Chen, Xuelei; Oppermann, Niels; Pen, Ue-Li; Timbie, Peter T.

2017-06-01

I report results from 21-cm intensity maps acquired from the Parkes radio telescope and cross-correlated with galaxy maps from the 2dF galaxy survey. The data span the redshift range 0.057small scales, around k~1.0 hMpc^-1, compared to the 2dF auto-power spectrum and the theoretical dark matter power spectrum. This indicates either a lack of clustering of neutral hydrogen (HI) at small scales or a small correlation coefficient between optical galaxies and HI, or some combination of the two. A lack of small scale HI clustering would be qualitatively similar to measurements of HI-selected galaxy clustering from the HIPASS and ALFALFA surveys at slightly lower redshifts.

Fermentable soluble fibres spare amino acids in healthy dogs fed a low-protein diet.

PubMed

Wambacq, Wendy; Rybachuk, Galena; Jeusette, Isabelle; Rochus, Kristel; Wuyts, Brigitte; Fievez, Veerle; Nguyen, Patrick; Hesta, Myriam

2016-06-28

Research in cats has shown that increased fermentation-derived propionic acid and its metabolites can be used as alternative substrates for gluconeogenesis, thus sparing amino acids for other purposes. This amino acid sparing effect could be of particular interest in patients with kidney or liver disease, where this could reduce the kidneys'/liver's burden of N-waste removal. Since dogs are known to have a different metabolism than the obligatory carnivorous cat, the main objective of this study was to assess the possibility of altering amino acid metabolism through intestinal fermentation in healthy dogs. This was studied by supplementing a low-protein diet with fermentable fibres, hereby providing an initial model for future studies in dogs suffering from renal/liver disease. Eight healthy dogs were randomly assigned to one of two treatment groups: sugar beet pulp and guar gum mix (SF: soluble fibre, estimated to mainly stimulate propionic acid production) or cellulose (IF: insoluble fibre). Treatments were incorporated into a low-protein (17 %) extruded dry diet in amounts to obtain similar total dietary fibre (TDF) contents for both diets (9.4 % and 8.2 % for the SF and IF diet, respectively) and were tested in a 4-week crossover feeding trial. Apparent faecal nitrogen digestibility and post-prandial fermentation metabolites in faeces and plasma were evaluated. Dogs fed the SF diet showed significantly higher faecal excretion of acetic and propionic acid, resulting in a higher total SCFA excretion compared to IF. SF affected the three to six-hour postprandial plasma acylcarnitine profile by significantly increasing AUC of acetyl-, propionyl-, butyryl- + isobutyryl-, 3-OH-butyryl-, 3-OH-isovaleryl- and malonyl-L-carnitine. Moreover, the amino acid plasma profile at that time was modified as leucine + isoleucine concentrations were significantly increased by SF, and a similar trend for phenylalanine and tyrosine's AUC was found. These results indicate

Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

NASA Astrophysics Data System (ADS)

Moussaid, A.; Schosseler, F.; Munch, J. P.; Candau, S. J.

1993-04-01

The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionizaiton degrees nearly quantitative agreement with the theory is found for the polyacrylic acide system.

Solubility of ocular therapeutic agents in self-emulsifying oils. I. Self-emulsifying oils for ocular drug delivery: solubility of indomethacin, aciclovir and hydrocortisone.

PubMed

Czajkowska-Kośnik, Anna; Sznitowska, Małgorzata

2009-01-01

Self-emulsifying drug delivery systems (SEDDS) were prepared by dissolving Cremophor EL, Tween 20, Tween 80 and Span 80 (1% or 5%) in oils (Miglyol 812 or castor oil). Solubilities of three ophthalmic drugs, namely aciclovir, hydrocortisone and indomethacin were determined in these systems. In addition, the effect of a small amount of water (0.5% and 2%) on solubilization properties of the systems was estimated. Of the three substances, indomethacin showed the best solubility in Miglyol while aciclovir was practically insoluble in this oil. The surfactants usually increased drug solubility in the oily phase. Only Tween 20 was found to decrease the solubility of aciclovir and hydrocortisone in Miglyol. Addition of a small amount of water to the oil/surfactant system increased solubility of hydrocortisone, but not of indomethacin. The results of the current study may be utilized to design a suitable composition of SEDDS and allow continuation of research on this type of drug carriers.

Chemical synthesis of water-soluble, chiral conducting-polymer complexes

DOEpatents

Wang, Hsing-Lin; McCarthy, Patrick A.; Yang, Sze Cheng

2003-01-01

The template-guided synthesis of water-soluble, chiral conducting polymer complexes is described. Synthesis of water-soluble polyaniline complexes is achieved by carefully controlling the experimental parameters such as; acid concentration, ionic strength, monomer/template ratio, total reagent concentration, and order of reagent addition. Chiral (helical) polyaniline complexes can be synthesized by addition of a chiral inducing agent (chiral acid) prior to polymerization, and the polyaniline helix can be controlled by the addition of the (+) or (-) form of the chiral acid. Moreover the quantity of chiral acid and the salt content has a significant impact on the degree of chirality in the final polymer complexes. The polyaniline and the template have been found to be mixed at the molecular level which results in chiral complexes that are robust through repeated doping and dedoping cycles.

Nutritional composition and solubility of edible bird nest (Aerodramus fuchiphagus)

NASA Astrophysics Data System (ADS)

Halimi, Nurfatin Mohd; Kasim, Zalifah Mohd; Babji, Abdul Salam

2014-09-01

Edible bird nest (EBN) produced by certain swiftlet species mainly, Aerodromus fuciphagus. The objectives of this study were to determine and compare the proximate and amino acid composition of EBN obtained from two regions in Peninsular Malaysia (Pahang-A & Terengganu-B). The solubility of edible bird nest with varying pH, temperature and time was also investigated in this study. The results showed that, the EBN contained crude protein accounted to 58.55% (A) and 55.48% (B), carbohydrate at22.28% (A) & 25.79% (B), moisture content 15.90% (A) & 15.87% (B), fat, 0.67% (A) & and 0.29% (B) and ash contents 2.60% (A) & 2.57% (B) respectively. The major amino acids found in edible bird nest EBN were Glutamic acid (9.61%), Aspartic acid (6.34%), Lysine (5.44 %) and also Leucine (5.30%). The total solubility of EBN was also found to be increased when the temperature was increased increase with distilled water yielding the highest total solubility of EBN compared to others buffer (different pH) solutions.

Latitudinal distributions of atmospheric dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the western North Pacific: Sources and formation pathways

NASA Astrophysics Data System (ADS)

Bikkina, Srinivas; Kawamura, Kimitaka; Miyazaki, Yuzo

2015-05-01

The present study aims to assess the molecular distributions of water-soluble dicarboxylic acids (diacids: C2-C12), oxocarboxylic acids (C2-C9), and α-dicarbonyls (glyoxal and methylglyoxal) in aerosols collected over the western North Pacific (WNP) during a summer cruise (August to September 2008). The measured water-soluble organics show pronounced latitudinal distributions with higher concentrations in the region of 30°N-45°N (average 63 ng m-3) than 10°N-30°N (18 ng m-3). Mass fraction of oxalic acid (C2) in total aliphatic diacids (ΣC2-C12) showed higher values (72 ± 10%) in lower latitude (10°N-30°N) than that (56 ± 16%) in higher latitude (30°N-45°N), suggesting a photochemical production of C2 due to an increased insolation over the tropical WNP. A similar trend was found in other diagnostic ratios such as oxalic to succinic (C2/C4) and oxalic to glyoxylic acid (C2/ωC2), which further corroborate an enhanced photochemical aging over the WNP. In addition, relative abundances of oxalic acid in total diacids showed a marked increase as a function of ambient temperature, supporting their photochemical production. Constantly low concentration ratios of adipic and phthalic acids relative to azelaic acid suggest a small contribution of anthropogenic sources and an importance of oceanic sources during the study period. Significant production of C2 through oxidation of biogenic volatile organic compounds emitted from the sea surface is also noteworthy, as inferred from the strong linear correlations among water-soluble organic carbon, methanesulphonic acid, and oxalic acid. Sea-to-air emission of unsaturated fatty acids also contributes to formation of diacids over the WNP.

Effect of atmospheric organic complexation on iron-bearing dust solubility

NASA Astrophysics Data System (ADS)

Paris, R.; Desboeufs, K. V.

2013-02-01

Recent studies reported that the effect of organic complexation may be a potentially important process to be considered in models to estimate atmospheric iron flux to the ocean. In this study, we investigated this effect by a series of dissolution experiments on iron-bearing dust in presence or absence of various organic compounds typically found in the atmospheric waters (acetate, formate, oxalate, malonate, succinate, glutarate, glycolate, lactate, tartrate and humic acid as an analogue of humic like substances (HULIS)). Only 4 of tested organic ligands (oxalate, malonate, tartrate and humic acid) caused an enhancement of iron solubility which was associated with an increase of dissolved Fe(II) concentrations. For all of these organic ligands, a positive linear dependence of iron solubility to organic concentrations was observed and showed that the extent of organic complexation on iron solubility decreased in order oxalate > malonate = tartrate > humic acid. This was attributed to the ability of electron donors of organic ligands and implied a reductive ligand-promoted dissolution. This study confirmed that oxalate is the most effective ligand playing on dust iron solubility and showed, for the first time, the potential effect of HULIS on iron dissolution in atmospheric conditions.

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

PubMed

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.

Synthesis of water soluble glycine capped silver nanoparticles and their surface selective interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agasti, Nityananda, E-mail: nnagasti@gmail.com; Singh, Vinay K.; Kaushik, N.K.

Highlights: • Synthesis of water soluble silver nanoparticles at ambient reaction conditions. • Glycine as stabilizing agent for silver nanoparticles. • Surface selective interaction of glycine with silver nanoparticles. • Glycine concentration influences crystalinity and optical property of silver nanoparticles. - Abstract: Synthesis of biocompatible metal nanoparticles has been an area of significant interest because of their wide range of applications. In the present study, we have successfully synthesized water soluble silver nanoparticles assisted by small amino acid glycine. The method is primarily based on reduction of AgNO{sub 3} with NaBH{sub 4} in aqueous solution under atmospheric air in themore » presence of glycine. UV–vis spectroscopy, transmission electron microscopy (TEM), X–ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and differential thermal analysis (DTA) techniques used for characterization of resulting silver nanoparticles demonstrated that, glycine is an effective capping agent to stabilize silver nanoparticles. Surface selective interaction of glycine on (1 1 1) face of silver nanoparticles has been investigated. The optical property and crystalline behavior of silver nanoparticles were found to be sensitive to concentration of glycine. X–ray diffraction studies ascertained the phase specific interaction of glycine on silver nanoparticles. Silver nanoparticles synthesized were of diameter 60 nm. We thus demonstrated an efficient synthetic method for synthesis of water soluble silver nanoparticles capped by amino acid under mild reaction conditions with excellent reproducibility.« less

Smart polyelectrolyte microcapsules as carriers for water-soluble small molecular drug.

PubMed

Song, Weixing; He, Qiang; Möhwald, Helmuth; Yang, Yang; Li, Junbai

2009-10-15

Heat treatment is introduced as a simple method for the encapsulation of low molecular weight water-soluble drugs within layer-by-layer assembled microcapsules. A water-soluble drug, procainamide hydrochloride, could thus be encapsulated in large amount and enriched by more than 2 orders of magnitude in the assembled PDADMAC/PSS capsules. The shrunk capsules could control the unloading rate of drugs, and the drugs could be easily unloaded using ultrasonic treatment. The encapsulated amount could be quantitatively controlled via the drug concentration in the bulk. We also found that smaller capsules possess higher encapsulation capability.

Protein Solubility, Digestibility and Fractionation after Germination of Sorghum Varieties

PubMed Central

Afify, Abd El-Moneim M. R.; El-Beltagi, Hossam S.; Abd El-Salam, Samiha M.; Omran, Azza A.

2012-01-01

The changes in crude protein, free amino acids, amino acid composition, protein solubility, protein fractionation and protein digestibility after germination of sorghum were investigated. Sorghum varieties (Dorado, Shandaweel-6, Giza-15) were soaked for 20 h followed by germination for 72 h; the results revealed that crude protein and free amino acids in raw sorghum varieties ranged from 10.62 to 12.46% and 0.66 to 1.03 mg/g, respectively. Shandaweel-6 was the highest variety in crude protein and free amino acids content. After germination, crude protein was decreased and free amino acids were increased. There was an increase in content of valine and phenylalanine amino acids after germination. On the other hand, there was a decrease in most of amino acids after germination. After germination protein solubility was significantly increased. Regarding protein fractions, there was an increase in albumin, globulin and kafirin proteins and a decrease in cross linked kafirin and cross linked glutelin after germination. PMID:22319611

An aircraft measurement technique for formaldehyde and soluble carbonyl compounds

NASA Astrophysics Data System (ADS)

Lee, Yin-Nan; Zhou, Xianliang; Leaitch, W. Richard; Banic, Catharine M.

1996-12-01

An aircraft technique was developed for measuring ambient concentrations of formaldehyde and a number of soluble carbonyl compounds, including glycolaldehyde, glyoxal, methylglyoxal, glyoxylic acid, and pyruvic acid. Sampling was achieved by liquid scrubbing using a glass coil scrubber in conjunction with an autosampler which collected 5-min integrated liquid samples in septum-sealed vials. Analysis was performed on the ground after flight using high-performance liquid chromatography following derivatization of the carbonyl analytes with 2,4-dinitrophenylhydrazine; the limit of detection was 0.01 to 0.02 parts per billion by volume (ppbv) in the gas phase. Although lacking a real-time capability, this technique offers the advantage of simultaneously measuring six carbonyl compounds, savings in space and power on the aircraft, and a dependable ground-based analysis. This technique was deployed on the Canadian National Research Council DHC-6 Twin Otter during the 1993 summer intensive of the North Atlantic Regional Experiment. The data obtained on August 28, 1993, during a pollutant transport episode are presented as an example of the performance and capability of this technique.

The Lack of Small Craters on Eros is not due to the Yarkovsky Effect

NASA Astrophysics Data System (ADS)

O'Brien, David P.; Greenberg, R.

2007-10-01

Eros approaches saturation for craters larger than 200 m in diameter, but is significantly depleted in smaller craters [1]. It has been suggested that this could reflect a paucity of small impactors in the main belt, due to their removal by the Yarkovsky effect [1,2]. Here we present the results of a self-consistent collisional and dynamical evolution model for the main belt and NEAs, along with a model for the evolution of asteroid crater populations, that show that Eros' lack of small craters is not likely due to the depletion of small impactors by the Yarkovsky effect, or any other depletion mechanism. To produce a main-belt size distribution that is suitably depleted in small impactors to match Eros' small crater population requires a more extreme size-dependent removal rate than the Yarkovsky effect and Poynting-Robertson drag can provide. Using such an extreme removal rate introduces a wave into the model main-belt size distribution that propagates to large sizes, and is inconsistent with the observed main-belt population. Similarly, it introduces a wave in the model NEA population that is inconsistent with the observed NEAs. Eros is not alone in showing a depletion of small craters. Recent observations of the asteroid Itokawa by the Hyabusa spacecraft show relatively few craters, and Yarkovsky depletion of small impactors has again been suggested as a possible explanation [3]. Our work shows that a substantial depletion of small impactors from the main belt would have consequences at large sizes, inconsistent with observations of the actual main-belt and NEA size distributions. Other explanations for the depletion of small craters on asteroid surfaces must be explored [eg. 4,5]. References: [1] Chapman (2002), Icarus 155, p.104. [2] Bell (2001), LPSC XXXII, no.1964. [3] Saito (2006), Science 312, p.1341. [4] Richardson (2004), Science 306, p.1526. [5] Greenberg (2003), DPS 35, no.24.06.

Uranium (VI) solubility in carbonate-free ERDA-6 brine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucchini, Jean-francois; Khaing, Hnin; Reed, Donald T

2010-01-01

When present, uranium is usually an element of importance in a nuclear waste repository. In the Waste Isolation Pilot Plant (WIPP), uranium is the most prevalent actinide component by mass, with about 647 metric tons to be placed in the repository. Therefore, the chemistry of uranium, and especially its solubility in the WIPP conditions, needs to be well determined. Long-term experiments were performed to measure the solubility of uranium (VI) in carbonate-free ERDA-6 brine, a simulated WIPP brine, at pC{sub H+} values between 8 and 12.5. These data, obtained from the over-saturation approach, were the first repository-relevant data for themore » VI actinide oxidation state. The solubility trends observed pointed towards low uranium solubility in WIPP brines and a lack of amphotericity. At the expected pC{sub H+} in the WIPP ({approx} 9.5), measured uranium solubility approached 10{sup -7} M. The objective of these experiments was to establish a baseline solubility to further investigate the effects of carbonate complexation on uranium solubility in WIPP brines.« less

Glucansucrases from lactic acid bacteria which produce water-insoluble polysaccharides from sucrose

USDA-ARS?s Scientific Manuscript database

Dextrans and related glucans produced from sucrose by lactic acid bacteria have been studied for many years and are used in numerous commercial applications and products. Most of these glucans are water-soluble, except for a few notable exceptions from cariogenic Streptococcus spp. and a very small ...

Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T.S.

1999-08-11

Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitationmore » process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the

The dynamics of folic acid metabolism in an adult given a small tracer dose of 14C-folic acid.

PubMed

Clifford, A J; Arjomand, A; Dueker, S R; Schneider, P D; Buchholz, B A; Vogel, J S

1998-01-01

Folate is an essential nutrient that is involved in many metabolic pathways, including amino acid interconversions and nucleotide (DNA) synthesis. In genetically susceptible individuals and populations, dysfunction of folate metabolism is associated with severe illness. Despite the importance of folate, major gaps exist in our quantitative understanding of folate metabolism in humans. The gaps exist because folate metabolism is complex, a suitable animal model that mimics human folate metabolism has not been identified, and suitable experimental protocols for in vivo studies in humans are not developed. In general, previous studies of folate metabolism have used large doses of high specific activity tritium and 14C-labeled folates in clinical patients. While stable isotopes such as deuterium and 13C-labeled folate are viewed as ethical alternatives to radiolabeled folates for studying metabolism, the lack of sensitive mass spectrometry methods to quantify them has impeded advancement of the field using this approach. In this chapter, we describe a new approach that uses a major analytical breakthrough, Accelerator Mass Spectrometry (AMS). Because AMS can detect attomole concentrations of 14C, small radioactive dosages (nCi) can be safely administered to humans and traced over long periods of time. The needed dosages are sufficiently small that the total radiation exposure is only a fraction of the natural annual background radiation of Americans, and the generated laboratory waste may legally be classified non-radioactive in many cases. The availability of AMS has permitted the longest (202 d) and most detailed study to date of folate metabolism in a healthy adult human volunteer. Here we demonstrate the feasibility of our approach and illustrate its potential by determining empirical kinetic values of folate metabolism. Our data indicate that the mean sojourn time for folate is in the range of 93 to 120 d. It took > or = 350 d for the absorbed portion of small

Using NMR chemical shift imaging to monitor swelling and molecular transport in drug-loaded tablets of hydrophobically modified poly(acrylic acid): methodology and effects of polymer (in)solubility.

PubMed

Knöös, Patrik; Topgaard, Daniel; Wahlgren, Marie; Ulvenlund, Stefan; Piculell, Lennart

2013-11-12

A new technique has been developed using NMR chemical shift imaging (CSI) to monitor water penetration and molecular transport in initially dry polymer tablets that also contain small low-molecular weight compounds to be released from the tablets. Concentration profiles of components contained in the swelling tablets could be extracted via the intensities and chemical shift changes of peaks corresponding to protons of the components. The studied tablets contained hydrophobically modified poly(acrylic acid) (HMPAA) as the polymer component and griseofulvin and ethanol as hydrophobic and hydrophilic, respectively, low-molecular weight model compounds. The water solubility of HMPAA could be altered by titration with NaOH. In the pure acid form, HMPAA tablets only underwent a finite swelling until the maximum water content of the polymer-rich phase, as confirmed by independent phase studies, had been reached. By contrast, after partial neutralization with NaOH, the polyacid became fully miscible with water. The solubility of the polymer affected the water penetration, the polymer release, and the releases of both ethanol and griseofulvin. The detailed NMR CSI concentration profiles obtained highlighted the clear differences in the disintegration/dissolution/release behavior for the two types of tablet and provided insights into their molecular origin. The study illustrates the potential of the NMR CSI technique to give information of importance for the development of pharmaceutical tablets and, more broadly, for the general understanding of any operation that involves the immersion and ultimate disintegration of a dry polymer matrix in a solvent.

Effect of atmospheric organic complexation on iron-bearing dust solubility

NASA Astrophysics Data System (ADS)

Paris, R.; Desboeufs, K. V.

2013-05-01

Recent studies reported that the effect of organic complexation may be a potentially important process to be considered by models estimating atmospheric iron flux to the ocean. In this study, we investigated this process effect by a series of dissolution experiments on iron-bearing dust in the presence or the absence of various organic compounds (acetate, formate, oxalate, malonate, succinate, glutarate, glycolate, lactate, tartrate and humic acid as an analogue of humic like substances, HULIS) typically found in atmospheric waters. Only 4 of tested organic ligands (oxalate, malonate, tartrate and humic acid) caused an enhancement of iron solubility which was associated with an increase of dissolved Fe(II) concentrations. For all of these organic ligands, a positive linear dependence of iron solubility to organic concentrations was observed and showed that the extent of organic complexation on iron solubility decreased in the following order: oxalate >malonate = tartrate > humic acid. This was attributed to the ability of electron donors of organic ligands and implies a reductive ligand-promoted dissolution. This study confirms that among the known atmospheric organic binding ligands of Fe, oxalate is the most effective ligand promoting dust iron solubility and showed, for the first time, the potential effect of HULIS on iron dissolution under atmospheric conditions.

Fatty acids and fat-soluble vitamins in ewe's milk predicted by near infrared reflectance spectroscopy. Determination of seasonality.

PubMed

Revilla, I; Escuredo, O; González-Martín, M I; Palacios, C

2017-01-01

The aim of the present work was to determine the fatty acid and fat-soluble vitamin composition and the season of ewe's milk production using NIR spectroscopy. 219 ewe's milk samples from different breeds and feeding regimes were taken each month over one year. Fatty acids were analyzed by gas chromatography, and retinol and α-, and γ-tocopherol by liquid chromatography. The results showed that the quantification was more accurate for the milk dried on paper, except for vitamins. Calibration statistical descriptors on milk dried on paper were good for capric, lauric, myristic, palmitoleic, stearic and oleic acids, and acceptable for caprilic, undecanoic, 9c, 11tCLA, ΣCLA, PUFA, ω3, ω6, retinol and α-tocopherol. The equations for the discrimination of seasonality was obtained using the partial least squares discriminant analysis (PLSDA) algorithm. 93% of winter samples and 89% of summer samples were correctly classified using the NIR spectra of milk dried on paper. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sampling and analysis of airborne resin acids and solvent-soluble material derived from heated colophony (rosin) flux: a method to quantify exposure to sensitizing compounds liberated during electronics soldering.

PubMed

Smith, P A; Son, P S; Callaghan, P M; Jederberg, W W; Kuhlmann, K; Still, K R

1996-07-17

Components of colophony (rosin) resin acids are sensitizers through dermal and pulmonary exposure to heated and unheated material. Significant work in the literature identifies specific resin acids and their oxidation products as sensitizers. Pulmonary exposure to colophony sensitizers has been estimated indirectly through formaldehyde exposure. To assess pulmonary sensitization from airborne resin acids, direct measurement is desired, as the degree to which aldehyde exposure correlates with that of resin acids during colophony heating is undefined. Any analytical method proposed should be applicable to a range of compounds and should also identify specific compounds present in a breathing zone sample. This work adapts OSHA Sampling and Analytical Method 58, which is designed to provide airborne concentration data for coal tar pitch volatile solids by air filtration through a glass fiber filter, solvent extraction of the filter, and gravimetric analysis of the non-volatile extract residue. In addition to data regarding total soluble material captured, a portion of the extract may be subjected to compound-specific analysis. Levels of soluble solids found during personal breathing zone sampling during electronics soldering in a Naval Aviation Depot ranged from below the "reliable quantitation limit" reported in the method to 7.98 mg/m3. Colophony-spiked filters analyzed in accordance with the method (modified) produced a limit of detection for total solvent-soluble colophony solids of 10 micrograms/filter. High performance liquid chromatography was used to identify abietic acid present in a breathing zone sample.

Micelles from lipid derivatives of water-soluble polymers as delivery systems for poorly soluble drugs.

PubMed

Lukyanov, Anatoly N; Torchilin, Vladimir P

2004-05-07

Polymeric micelles have a whole set of unique characteristics, which make them very promising drug carriers, in particular, for poorly soluble drugs. Our review article focuses on micelles prepared from conjugates of water-soluble polymers, such as polyethylene glycol (PEG) or polyvinyl pyrrolidone (PVP), with phospholipids or long-chain fatty acids. The preparation of micelles from certain polymer-lipid conjugates and the loading of these micelles with various poorly soluble anticancer agents are discussed. The data on the characterization of micellar preparations in terms of their morphology, stability, longevity in circulation, and ability to spontaneously accumulate in experimental tumors via the enhanced permeability and retention (EPR) effect are presented. The review also considers the preparation of targeted immunomicelles with specific antibodies attached to their surface. Available in vivo results on the efficiency of anticancer drugs incorporated into plain micelles and immunomicelles in animal models are also discussed.

Micropore surface area of alkali-soluble plant macromolecules (humic acids) drives their decomposition rates in soil.

PubMed

Papa, Gabriella; Spagnol, Manuela; Tambone, Fulvia; Pilu, Roberto; Scaglia, Barbara; Adani, Fabrizio

2010-02-01

Previous studies suggested that micropore surface area (MSA) of alkali-soluble bio-macromolecules of aerial plant residues of maize constitutes an important factor that explains their humification in soil, that is, preservation against biological degradation. On the other hand, root plant residue contributes to the soil humus balance, as well. Following the experimental design used in a previous paper published in this journal, this study shows that the biochemical recalcitrance of the alkali-soluble acid-insoluble fraction of the root plant material, contributed to the root maize humification of both Wild-type maize plants and its corresponding mutant brown midrib (bm3), this latter characterized by reduced lignin content. Humic acids (HAs) existed in root (root-HAs) were less degraded in soil than corresponding HAs existed in shoot (shoot-HAs): shoot-HAs bm3 (48%)>shoot-HAs Wild-type (37%)>root-HAs Wild-type (33%)>root-HAs bm3 (22%) (degradability shown in parenthesis). These differences were related to the MSA of HAs, that is, root-HAs having a higher MSA than shoot-HAs: shoot-HAs bm3 (41.43+/-1.2m(2)g(-1))

The solubility parameter for biomedical polymers-Application of inverse gas chromatography.

PubMed

Adamska, K; Voelkel, A; Berlińska, A

2016-08-05

The solubility parameter seems to be a useful tool for thermodynamic characterisation of different materials. The solubility parameter concept can be used to predict sufficient miscibility or solubility between a solvent and a polymer, as well as components of co-polymer matrix in composite biomaterials. The values of solubility parameter were determined for polycaprolactone (PCL), polylactic acid (PLA) and polyethylene glycol (PEG) by using different procedures and experimental data, collected by means of inverse gas chromatography. Copyright © 2016 Elsevier B.V. All rights reserved.

Removal of Water-Soluble Extractives Improves the Enzymatic Digestibility of Steam-Pretreated Softwood Barks.

PubMed

Frankó, Balázs; Carlqvist, Karin; Galbe, Mats; Lidén, Gunnar; Wallberg, Ola

2018-02-01

Softwood bark contains a large amounts of extractives-i.e., soluble lipophilic (such as resin acids) and hydrophilic components (phenolic compounds, stilbenes). The effects of the partial removal of water-soluble extractives before acid-catalyzed steam pretreatment on enzymatic digestibility were assessed for two softwood barks-Norway spruce and Scots pine. A simple hot water extraction step removed more than half of the water-soluble extractives from the barks, which improved the enzymatic digestibility of both steam-pretreated materials. This effect was more pronounced for the spruce than the pine bark, as evidenced by the 30 and 11% glucose yield improvement, respectively, in the enzymatic digestibility. Furthermore, analysis of the chemical composition showed that the acid-insoluble lignin content of the pretreated materials decreased when water-soluble extractives were removed prior to steam pretreatment. This can be explained by a decreased formation of water-insoluble "pseudo-lignin" from water-soluble bark phenolics during the acid-catalyzed pretreatment, which otherwise results in distorted lignin analysis and may also contribute to the impaired enzymatic digestibility of the barks. Thus, this study advocates the removal of extractives as the first step in the processing of bark or bark-rich materials in a sugar platform biorefinery.

Assessing the solubility controls on vanadium in groundwater, northeastern San Joaquin Valley, CA

USGS Publications Warehouse

Wright, Michael T.; Stollenwerk, Kenneth G.; Belitz, Kenneth

2014-01-01

The solubility controls on vanadium (V) in groundwater were studied due to concerns over possible harmful health effects of ingesting V in drinking water. Vanadium concentrations in the northeastern San Joaquin Valley ranged from 25 μg/L) and lowest in samples collected from anoxic groundwater (70% 2VO4−. Adsorption/desorption reactions with mineral surfaces and associated oxide coatings were indicated as the primary solubility control of V5+ oxyanions in groundwater. Environmental data showed that V concentrations in oxic groundwater generally increased with increasing groundwater pH. However, data from adsorption isotherm experiments indicated that small variations in pH (7.4–8.2) were not likely as an important a factor as the inherent adsorption capacity of oxide assemblages coating the surface of mineral grains. In suboxic groundwater, accurate SM modeling was difficult since Eh measurements of source water were not measured in this study. Vanadium concentrations in suboxic groundwater decreased with increasing pH indicating that V may exist as an oxycationic species [e.g. V(OH)3+]. Vanadium may complex with dissolved inorganic and organic ligands under suboxic conditions, which could alter the adsorption behavior of V in groundwater. Speciation modeling did not predict the existence of V-inorganic ligand complexes and organic ligands were not collected as part of this study. More work is needed to determine processes governing V solubility under suboxic groundwater conditions. Under anoxic groundwater conditions, SM predicts that aqueous V exists as the uncharged V(OH)3 molecule. However, exceedingly low V concentrations show that V is sparingly soluble in anoxic conditions. Results indicated that V may be precipitating as V3+- or mixed V3+/Fe3+-oxides in anoxic groundwater, which is consistent with results of a previous study. The fact that V appears insoluble in anoxic (Fe reducing) redox conditions indicates that the behavior of V is different than

Effect of composition of simulated intestinal media on the solubility of poorly soluble compounds investigated by design of experiments.

PubMed

Madsen, Cecilie Maria; Feng, Kung-I; Leithead, Andrew; Canfield, Nicole; Jørgensen, Søren Astrup; Müllertz, Anette; Rades, Thomas

2018-01-01

The composition of the human intestinal fluids varies both intra- and inter-individually. This will influence the solubility of orally administered drug compounds, and hence, the absorption and efficacy of compounds displaying solubility limited absorption. The purpose of this study was to assess the influence of simulated intestinal fluid (SIF) composition on the solubility of poorly soluble compounds. Using a Design of Experiments (DoE) approach, a set of 24 SIF was defined within the known compositions of human fasted state intestinal fluid. The SIF were composed of phospholipid, bile salt, and different pH, buffer capacities and osmolarities. On a small scale semi-robotic system, the solubility of 6 compounds (aprepitant, carvedilol, felodipine, fenofibrate, probucol, and zafirlukast) was determined in the 24 SIF. Compound specific models, describing key factors influencing the solubility of each compound, were identified. Although all models were different, the level of phospholipid and bile salt, the pH, and the interactions between these, had the biggest influences on solubility overall. Thus, a reduction of the DoE from five to three factors was possible (11-13 media), making DoE solubility studies feasible compared to single SIF solubility studies. Applying this DoE approach will lead to a better understanding of the impact of intestinal fluid composition on the solubility of a given drug compound. Copyright © 2017 Elsevier B.V. All rights reserved.

Acylation of keratinocyte transglutaminase by palmitic and myristic acids in the membrane anchorage region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakravarty, R.; Rice, R.H.

1989-01-05

The membrane-bound form of keratinocyte transglutaminase was found to be labeled by addition of (/sup 3/H) acetic, (/sup 3/H)myristic, or (/sup 3/H)palmitic acids to the culture medium of human epidermal cells. Acid methanolysis and high performance liquid chromatography analysis of palmitate-labeled transglutaminase yielded only methyl palmitate. In contrast, analysis of the myristate-labeled protein yielded approximately 40% methyl myristate and 60% methyl palmitate. Incorporation of neither label was significantly affected by cycloheximide inhibition of protein synthesis. The importance of the fatty acid moiety for membrane anchorage was demonstrated in three ways. First, the enzyme was solubilized from the particulate fraction ofmore » cell extracts by treatment with neutral 1 M hydroxylamine, which was sufficient to release the fatty acid label. Second, solubilization of active enzyme from the particulate fraction upon mild trypsin treatment resulted in a reduction in size by approximately 10 kDa and removal of the fatty acid radiolabels. Third, the small fraction of soluble transglutaminase in cell extracts was found almost completely to lack fatty acid labeling. Keratinocyte transglutaminase translated from poly(A+) RNA in a reticulocyte cell-free system was indistinguishable in size from the native enzyme, suggesting anchorage requires only minor post-translational processing. Thus, the data are highly compatible with membrane anchorage by means of fatty acid acylation within 10 kDa of the NH/sub 2/ or COOH terminus.« less

The role of carbon solubility in Fe-C nano-clusters on the growth of small single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Curtarolo, Stefano; Awasthy, Neha; Setyawan, Wahyu; Mora, Elena; Tokune, Toshio; Bolton, Kim; Harutyunyan, Avetik

2008-03-01

Various diameters of alumina-supported Fe catalysts are used to grow single-walled carbon nanotubes (SWCNTs) with chemical vapor decomposition. We find that the reduction of the catalyst size requires an increase of the minimum temperature necessary for the growth. We address this phenomenon in terms of solubility of C in Fe nanoclusters and, by using first principles calculations, we devise a simple model to predict the behavior of the phases competing for stability in Fe-C nanoclusters at low temperature. We show that, as a function particles size, there are three scenarios compatible with steady state-, limited- and no-growth of SWCNTs, corresponding to unaffected, reduced and no solubility of C in the particles. The result raises previously unknown concerns about the growth feasibility of small and very-long SWCNTs within the current Fe CVD technology, and suggests new strategies in the search of better catalysts. Research supported by Honda R.I. and NSF.

Soluble arabinoxylan alters digesta flow and protein digestion of red meat-containing diets in pigs.

PubMed

Zhang, Dagong; Williams, Barbara A; Mikkelsen, Deirdre; Li, Xiuhua; Keates, Helen L; Lisle, Allan T; Collins, Helen M; Fincher, Geoffrey B; Bird, Anthony R; Topping, David L; Gidley, Michael J; Bryden, Wayne L

2015-09-01

The aim of this study was to investigate how a moderate increase in dietary meat content combined (or not) with soluble fibre would influence protein digestion as well as digesta characteristics and flow. Four groups of pigs were fed Western-style diets (high-protein/high-fat) containing two types of barbecued red meat, one with and one without a wheat arabinoxylan-rich fraction. After 4 wk, digesta samples were collected from small and large intestinal sites and analyzed for protein, amino acids, dry matter, and acid-insoluble ash. Tissue samples were also collected from each site. Arabinoxylan consumption led to somewhat lower apparent protein digestibility within the small and large intestines as well as shorter mean retention times. This suggests that the lowered protein digestibility is due, at least partly, to shorter access time to digestive proteases and absorptive surfaces. Additionally, digesta mass was higher in pigs fed arabinoxylan while dry matter (%) was lower, indicating an increased digesta water-holding capacity due to the presence of a soluble dietary fiber. Data showed that solubilized wheat arabinoxylan provides potential health benefits through decreased protein digestibility, increased digesta mass, and reduced mean retention time, even for diets with a moderately higher protein content. These factors are associated with efficiency of digestion and satiety, both of which have implications for prevention of obesity and other health disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

A Bifunctional Dimethylsulfoxide Substitute Enhances the Aqueous Solubility of Small Organic Molecules

PubMed Central

Sprachman, Melissa M.

2012-01-01

Abstract An oxetane-substituted sulfoxide has demonstrated potential as a dimethylsulfoxide substitute for enhancing the dissolution of organic compounds with poor aqueous solubilities. This sulfoxide may find utility in applications of library storage and biological assays. For the model compounds studied, significant solubility enhancements were observed using the sulfoxide as a cosolvent in aqueous media. Brine shrimp, breast cancer (MDA-MB-231), and liver cell line (HepG2) toxicity data for the new additive are also presented, in addition to comparative IC50 values for a series of PKD1 inhibitors. PMID:22192308

Chemical Characteristics of Water-Soluble Ions in Particulate Matter in Three Metropolitan Areas in the North China Plain

PubMed Central

Dao, Xu; Wang, Zhen; Lv, Yibing; Teng, Enjiang; Zhang, Linlin; Wang, Chao

2014-01-01

PM2.5 and PM10 samples were collected simultaneously in each season in Beijing, Tianjin and Shijiazhuang to identify the characteristics of water-soluble ion compositions in the North China Plain. The water-soluble ions displayed significant seasonal variation. The dominant ions were NO3 −, SO4 2−, NH4 + and Cl−, accounting for more than 90% and 86% to the mass of total water-soluble ions in PM2.5 and PM10, respectively. The anion/cation ratio indicated that the ion acidity of each city varied both between sites and seasonally. Over 50% of the ion species were enriched in small particles ≤1 µm in diameter. The [NO3 −]/[SO4 2−] ratio indicated that vehicles accounted for the majority of the particulate pollution in Beijing. Shijiazhuang, a city highly reliant on coal combustion, had a higher SO4 2− concentration. PMID:25437210

Cocrystal solubility product analysis - Dual concentration-pH mass action model not dependent on explicit solubility equations.

PubMed

Avdeef, Alex

2017-12-15

A novel general computational approach is described to address many aspects of cocrystal (CC) solubility product (K sp ) determination of drug substances. The CC analysis program, pDISOL-X, was developed and validated with published model systems of various acid-base combinations of active pharmaceutical ingredients (APIs) and coformers: (i) carbamazepine cocrystal systems with 4-aminobenzoic acid, cinnamic acid, saccharin, and salicylic acid, (ii) for indomethacin with saccharin, (iii) for nevirapine with maleic acid, saccharin, and salicylic acid, and (iv) for gabapentin with 3-hydroxybenzoic acid. In all systems but gabapentin, the coformer is much more soluble than the API. The model systems selected are those with available published dual concentration-pH data, one set for the API and one set for the coformer, generally measured at eutectic points (thermodynamically-stable three phases: solution, cocrystal, and crystalline API or coformer). The carbamazepine-cinnamic acid CC showed a substantial elevation in the API equilibrium concentration above pH5, consistent with the formation of a complex between carbamazepine and cinnamate anion. The analysis of the gabapentin:3-hydroxybenzoic acid 1:1 CC system indicated four zones of solid suspensions: coformer (pH<3.25), coformer and cocrystal eutectic (pH3.25-4.44), cocrystal (pH4.44-5.62), and API (pH>5.62). The general approach allows for testing of many possible equilibrium models, including those comprising drug-coformer complexation. The program calculates the ionic strength at each pH. From this, the equilibrium constants are adjusted for activity effects, based on the Stokes-Robinson hydration theory. The complete speciation analysis of the CC systems may provide useful insights into pH-sensitive dissolution effects that could potentially influence bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

Solubility and modeling acid-base properties of adrenaline in NaCl aqueous solutions at different ionic strengths and temperatures.

PubMed

Bretti, Clemente; Cigala, Rosalia Maria; Crea, Francesco; De Stefano, Concetta; Vianelli, Giuseppina

2015-10-12

Solubility and acid-base properties of adrenaline were studied in NaCl aqueous solutions at different ionic strengths (0solubility of the ligand was calculated from simple mass balance equations, by using the free hydrogen concentration and the protonation constants of the ligand determined in the same experimental conditions of the solubility measurements. The salting-In or Out parameters and the activity coefficient of the neutral species were calculated by means of the Setschenow equation. The dependence of the protonation constants on the ionic strength was modeled by means of the Debye-Hückel type equation and of the SIT (Specific ion Interaction Theory) approach. The specific interaction parameters of the ion pairs were also reported. For the protonation constants, the following thermodynamic values at infinite dilution were obtained: T=298.15 K, logK1(H0)=10.674±0.018 and logK2(H0)=8.954±0.022; T=310.15K, logK1(H0)=10.355±0.018 and logK2(H0)=8.749±0.030. Copyright © 2015 Elsevier B.V. All rights reserved.