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Search Results: 1 - 10 of 607 matches for " Solubility "
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Calculation of Solubility of Oxyquinolinates  [PDF]
Anna M. Micha?owska-Kaczmarczyk, Tadeusz Micha?owski
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2014, DOI: 10.4236/jasmi.2014.43010
Abstract:

The solubilities (s, mol/L) of different oxyquinolinates (oxinates, MeL2) are calculated using the formulae obtained according to elementary algebra, with the use of Excel spreadsheets. The calculations are involved with solution of algebraic equation of the third degree, obtained on the basis of concentration balances. The root of this equation, , is then inserted into the charge balance, and resolved according to zeroing procedure. In principle, the calculations are related to aqueous media. Nonetheless, the extension on liquid-liquid extraction systems is also proposed.

Solubility and Dissolution in Terms of Generalized Approach to Electrolytic Systems Principles  [PDF]
Anna Maria Micha?owska-Kaczmarczyk, Tadeusz Micha?owski, Marcin Toporek, Andrzej Pietrzyk
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2015, DOI: 10.4236/jasmi.2015.54006
Abstract: The correct approach, based on the rules of conservation and detailed physicochemical/thermodynamic knowledge on the system considered is opposed to conventional approach to solubility and dissolution, based on stoichiometry of a reaction notation and on the solubility product (Ksp) of a precipitate. The correct approach is realized according to Generalized Approach to Electrolytic Systems (GATES) principles, with use of iterative programs applied for computational purposes. All the qualitative and quantitative knowledge is involved in the balances and independent expressions for the equilibrium constants. Three two-phase electrolytic systems with diversified chemical properties were selected carefully, from the viewpoint of their diversity. The results of calculations are presented graphically and discussed. The advantages of the GATES in resolution of two-phase (static) non-redox systems and one complex (dynamic) redox system are proved.
Measurement and Prediction of the Solubility of CO2 in Ester Mixture  [PDF]
Xia Gui, Zhigang Tang, Weiyang Fei
Low Carbon Economy (LCE) , 2011, DOI: 10.4236/lce.2011.21005
Abstract: The solubility of CO2 in ester mixtures under high pressures are studied in this article. The constant-volume method is used to determine the solubility of CO2 in DMC + diethyl carbonate system, DMC + propyl acetate system, DMC + propylene carbonate system, and DMC + ethylene carbonate system from 282.0 K to 303.0 K. It is found that the solubility of CO2 in four mixed solvents follows the Henry’s law and the linear compound has a greater ability to dissolve CO2 than the cyclic compound at the same temperature. Furthermore, a modified equation is proposed to fit the solution data and a better equation is obtained in this paper. This will be useful for the future research in the screening of a potential physical solvent for CO2 capture.
Synthesis of Soluble Polythiophene Partially Containing 3,4-Ethylenedioxythiophene and 3-Hexylthiophene by Polycondensation  [PDF]
Ichiro Imae, Hitoshi Sagawa, Takahiro Mashima, Kenji Komaguchi, Yousuke Ooyama, Yutaka Harima
Open Journal of Polymer Chemistry (OJPChem) , 2014, DOI: 10.4236/ojpchem.2014.43010
Abstract:

A novel poly(quinquethiophene) partially containing 3,4-ethylenedioxythiophene (EDOT) and 3-hexylthiophene, poly(3,3 ''''-dihexyl-3',4',3''',4'''-diethylenedioxy-2,2':5',2'':5'',2''':5''',2''''-quinquethiophene), was synthesized by three types of polycondensations. Among them, direct C-H coupling reaction gave the polymer with the highest molecular weight. The resulting polymer was soluble in common organic solvents. Absorption and fluorescence spectra of the polymer showed a remarkable red-shift compared with the corresponding monomer due to the expansion of effective π-conjugation length.

Aqueous Solubility Enhancement of Mirtazapine: Effect of Cosolvent and Surfactant  [PDF]
Kenneth E. Ezealisiji, Chika J. Mbah, Patience O. Osadebe
Pharmacology & Pharmacy (PP) , 2015, DOI: 10.4236/pp.2015.610049
Abstract: The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorly aqueous soluble drugs. Mirtazapine, a tetracyclic antidepressant used for the treatment of moderate to severe depression and anxiety, has very poor aqueous solubility. The objective of the study was to investigate the effect of solubilizing agents (cosolvents and surfactants) on the aqueous solubility of mirtazapine while envisaging that any significant improvement in its aqueous solubility could contribute towards alleviating the withdrawal symptoms often associated with the drug. The solubility of mirtazapine was determined at room temperature in aqueous mixtures of cosolvents (propylene glycol and polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80 and sodium lauryl sulfate). An exponential increase in mirtazapine solubility was observed when total drug solubility in water-cosolvent system was plotted against cosolvent fraction volume. Polyethylene glycol 400 gave larger solubilization capacity (σ) when compared to propylene glycol. With the surfactants, linear relationship between the total solubility of the drug in water-surfactant mixtures and surfactant concentration was noted. Sodium lauryl sulfate showed the largest solubilization power (k) when compared to the nonionic surfactants (polysorbate 20 and polysorbate 80 respectively). A linear relationship between standard free energy and partition coefficient was also observed. The result of the study shows that aqueous solubility of mirtazapine is significantly improved by cosolvency and micellization and therefore there exists the possibility of improving the withdrawal symptoms often experienced with the drug. It also suggests that large free energy is required for drugs with high partition coefficients to permeate the biological membrane.
Solubility of Alkylporphyrins
Galina M. Mamardashvili,Nugdzar Zh. Mamardashvili,Boris D. Berezin
Molecules , 2000, DOI: 10.3390/50600762
Abstract: The solubility in benzene and ethanol of 2,8,12,18-tetramethyl-3,7,13,17-tetrabuthylporphyrin with various substituents in the5,15-positions of the molecule is investigated. A comparative analysis of the influence of alkyl substituents on porphyrin solubility is carried out.
Bioavailability and Solubility of Different Calcium-Salts as a Basis for Calcium Enrichment of Beverages  [PDF]
Gaby Kressel
Food and Nutrition Sciences (FNS) , 2010, DOI: 10.4236/fns.2010.12009
Abstract: Background: When usual calcium consumption patterns were analysed most people in the U.S. and Europe consume less than the recommended daily allowance. Supplements and fortified foods offer alternative and additional sources of calcium to traditional food. Calcium carbonate is the most common supplement but it is less soluble in water and, therefore, not suitable for enrichment of beverages. New organic calcium salts have a better solubility but less is known about their bioavailability. In the present study, we assessed the solubility and bioavailability of the new organic calcium salts, calcium lactate citrate and calcium lactate malate, in comparison to the traditional supplements, calcium carbonate and calcium gluconate. Design: Randomized, single-blind, four way cross-over study comparing single doses of 500 mg calcium in the form of four different calcium-salts. Subjects were advised to consume 25 µg vitamin D3 daily two weeks prior to the start of the study and during the whole study period. Subjects: 20 healthy young men, Methods: Blood samples were drawn immediately before and 2, 4, 6, 8, 12 and 24 h after ingestion of the calcium preparation. Concentration of total calcium and intact parathyroid hormone were measured in the serum. Urine was collected at baseline and during the intervals 0-3, 3-6, 9-15 and 15-24 h and excretion of calcium, sodium and creatinine was examined. Results: The tested new salts were easily water soluble, significantly better than calcium gluconate. Calcium carbonate is almost insoluble. The bioavailability of the four different calcium salts was found to be almost identical. The maximum total serum calcium increased by 7.6 % two hours after ingestion calcium lactate citrate, by 7.4 % after calcium lactate malate, by 5.5 % after calcium carbonate, and by 5.8 % after calcium gluconate. Intact parathyroid hormone concentration showed the expected depression for calcium lactate citrate, calcium lactate malate and calcium carbonate, whereas the serum level was significantly higher after ingestion of calcium gluconate. Conclusion: Given an almost equivalent bioavailability of the four tested calcium salts, we conclude that the new salts calcium lactate citrate and calcium lactate malate are well suited for fortification of beverages and thus to increase the average daily calcium intake.
Nucleation Kinetics of L-Arginine, L-Lysine and L-Alanine Doped Potassium Dihydrogen Phosphate Crystals  [PDF]
K. D. Parikh, B. B. Parekh, D. J. Dave, M. J. Joshi
Journal of Crystallization Process and Technology (JCPT) , 2013, DOI: 10.4236/jcpt.2013.33015
Abstract: The solubility, induction period and nucleation parameters of pure and amino acids like L-arginine, L-lysine and L-alanine doped potassium dihydrogen phosphate (KDP) crystals have been determined. Solubility study of pure and amino acids doped KDP crystals were carried out for different temperatures. The induction period was measured at different supersaturation level. The nucleation parameters like interfacial tension, radius of critical nucleus and energy of formation were calculated based on the classical theory of nucleation. Values of different parameters were found to be larger for amino acid doped crystals than pure KDP crystal.
Solubility of Solids in Supercritical Fluids: The Mendez-Santiago Teja Model Revisited  [PDF]
Loubna Nasri, Zouhir Bensetiti
Advances in Chemical Engineering and Science (ACES) , 2015, DOI: 10.4236/aces.2015.53042
Abstract: For the development and enhancement of supercritical applications, it is crucial to know the solubility of the considered compound in the supercritical fluid (SCF) in order to determine the conditions to achieve the best outcome. Many models have been developed to calculate supercritical solubility behavior and most can be either a semi empirical relationship or based on an equation of state. The Mendez-Santiago and Teja (MST) model is one of the most semiempirical models used. In this work, a review of the (MST) model from an accuracy and ability viewpoint is accomplished to give concise discussion and so to the proposition of a modification.
Indomethacin solubility estimation in 1,4-dioxane + water mixtures by the extended hildebrand solubility approach
Ruidiaz, Miller A;Delgado, Daniel R;Martínez, Fleming;
Química Nova , 2011, DOI: 10.1590/S0100-40422011000900016
Abstract: extended hildebrand solubility approach (ehsa) was successfully applied to evaluate the solubility of indomethacin in 1,4-dioxane + water mixtures at 298.15 k. an acceptable correlation-performance of ehsa was found by using a regular polynomial model in order four of the w interaction parameter vs. solubility parameter of the mixtures (overall deviation was 8.9%). although the mean deviation obtained was similar to that obtained directly by means of an empiric regression of the experimental solubility vs. mixtures solubility parameters, the advantages of ehsa are evident because it requires physicochemical properties easily available for drugs.
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