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Vilas G. Gaikar - One of the best experts on this subject based on the ideXlab platform.
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hydrotropic extraction process for recovery of forskolin from coleus forskohlii roots
Industrial & Engineering Chemistry Research, 2009Co-Authors: Sanjay P Mishra, Vilas G. GaikarAbstract:A simple and rapid method based on hydrotropic solubilization is developed for isolation of forskolin from coleus forskohlii roots. The plant cells are permeabilized by aqueous hydrotrope solutions followed by extraction and solubilization of forskolin into the hydrotrope solutions of alkyl benzene sulfonates and carboxylates. The solubility of forskolin is increased by 350 times in the hydrotropic solutions and it is possible to recover 85% pure forskolin from the hydrotropic solutions by simple dilution with water. The purity of the recovered forskolin decreased from 85% to 70% on decreasing particle size of the roots. Nearly 80% of the forskolin having 50% purity was recovered from the coleus roots using 2.0 mol/dm3 aqueous sodium cumene sulfonate (Na−CS) solutions at 363 K. Na−CS showed the most efficient solubilization of forskolin from the Coleus roots among all the other Hydrotropes.
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effect of temperature on aggregation behavior of aqueous solutions of sodium cumene sulfonate
Journal of Molecular Liquids, 2007Co-Authors: Vikrant B Wagle, Prajesh S Kothari, Vilas G. GaikarAbstract:Aqueous solutions of sodium cumene sulfonate are characterized by various experimental techniques for its aggregation behavior as a function of temperature. Surface tensiometry, volumetric changes, vapor pressure osmometry, fluorescence polarization studies and enthalpy changes show changes in the solutions with increasing concentration and temperature. The apparent and partial molal volumes of the hydrotrope, derived from the density measurements, show a sharp increase at a characteristic minimum hydrotrope concentration. The osmotic coefficient of NaCS, obtained from vapor pressure osmometry, shows a significant deviation indicating aggregation of the hydrotrope molecules in aqueous solutions. NaCS, when used as an intrinsic fluorescent probe, reveals a non-polar environment in the aggregate with substantial microviscosity. The enthalpies of micellization obtained directly from the calorimetric measurements show a trend towards lower values with increasing temperature.
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recovery of diosgenin from dioscorea rhizomes using aqueous hydrotropic solutions of sodium cumene sulfonate
Industrial & Engineering Chemistry Research, 2004Co-Authors: Sanjay P Mishra, Vilas G. GaikarAbstract:Aqueous solutions of aromatic Hydrotropes were investigated for cell permeabilization and extraction of dioscin from dioscorea rhizomes. The extracted dioscin was further hydrolyzed in the same hydrotropic solutions to diosgenin without significant decomposition to 3,5-diene, unlike in the conventional process. The parameters affecting the extraction of dioscin, such as the nature and concentration of the hydrotrope, the temperature, and the particle size, were optimized. Sodium cumene sulfonate was the most efficient hydrotrope for the extraction of dioscin and also for its hydrolysis to diosgenin at 353 K. Diosgenin precipitates from aqueous NaCS solutions with >95% purity at 293 K because of its poor solubility in aqueous solutions.
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solubility of o p hydroxyacetophenones in aqueous solutions of sodium alkyl benzene sulfonate Hydrotropes
Journal of Chemical & Engineering Data, 2004Co-Authors: Y. P. Koparkar, Vilas G. GaikarAbstract:Hydrotropes enhance solubility of water-insoluble or sparingly soluble solutes such as o- and p-hydroxyacetophenones (HAPs) in aqueous solutions. The solubility of HAPs is experimentally determined in aqueous solutions of sodium cumene sulfonate (NaCS), sodium p-xylene sulfonate (NaXS), and sodium p-toluene sulfonate (NaPTS). The solubility of phenols increases almost by an order of magnitude at higher concentrations of the Hydrotropes in the order NaPTS, NaXS, and NaCS, at a given temperature. The solubility o-HAP was twice that of p-HAP in the NaCS solutions, and a similar trend was observed in other hydrotrope solutions. The solubility data was fitted in the Association model of hydrotropy to estimate the hydrotrope−hydrotrope and hydrotrope−solute interaction parameters. NaCS, the more hydrophobic hydrotrope, shows stronger interaction with the phenols and a higher association constant.
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small angle neutron scattering studies of mixed cetyl trimethylammonium bromide butyl benzene sulfonate solutions
Langmuir, 2002Co-Authors: O R Pal, Vilas G. Gaikar, J V Joshi, P S Goyal, V K AswalAbstract:The effect of Hydrotropes, sodium salts of butyl benzene sulfonate (Na-BBS), viz., n-butyl benzene sulfonate (Na-nBBS), iso-butyl benzene sulfonate (Na-iBBS), and tert-butyl benzene sulfonate (Na-tBBS), on microstructures of cetyl trimethylammonium bromide (CTAB) in aqueous solutions has been studied using small-angle neutron scattering (SANS) and viscosity changes. The viscosity of CTAB solutions increased with the addition of the Hydrotropes, but differently with different isomers. This behavior is attributed to the structural differences in the Hydrotropes. The SANS studies indicated the growth of the CTAB micelles on the addition of the Hydrotropes while the micellar shape changed from sphere to ellipsoid depending upon the structure of the hydrotrope. Na-nBBS showed the highest aggregation number and a lower fractional charge on the micelles as compared to the sterically hindered Na-tBBS, at the same concentration.
Nagendra N Gandhi - One of the best experts on this subject based on the ideXlab platform.
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ASSOCIATION MODEL OF HYDROTROPY FOR THE EFFECT OF Hydrotropes ON SOLUBILITY AND MASS TRANSFER COEFFICIENT OF ACETYLSALICYLIC ACID Research Article
2012Co-Authors: S. Thenesh Kumar, Nagendra N GandhiAbstract:Hydrotropes enhance the solubility and mass transfer coefficient of water-insoluble or sparingly soluble acetylsalicylic acid in aqueous solutions. The solubility of acetylsalicylic acid is experimentally determined in aqueous solutions of Hydrotropes such as sodium salicylate, sodium benzoate, nicotinamide and urea under a wide range of hydrotrope concentrations (0 to 3.0) mol/L and different system temperatures T = (303 to 333) K. The maximum enhancement factor value has been determined for both solubility and mass transfer coefficient. The effectiveness of Hydrotropes was measured in terms of Setschnew constant K s and reported for all Hydrotropes used in this study. The solubility data was fitted in the Association model of hydrotropy to estimate the hydrotrope-hydrotrope K hh and hydrotrope-solute K hs
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effect of Hydrotropes on solubility and mass transfer coefficient of 1 2 dichloroethane
2012Co-Authors: Antony Bertie Morais, Nagendra N GandhiAbstract:A comprehensive investigation on the solubility and mass transfer coefficient enhancement of 1,2-dichloroethane through hydrotropy has been undertaken. The solubility and mass transfer coefficient studies were carried out using Hydrotropes such as urea, citric acid, nicotinamide and sodium salicylate under the influence of a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303 to 333 K). It has been observed that the solubility of 1,2-dichloroethane increases with increase in hydrotrope concentration and also with system temperature. A Minimum Hydrotrope Concentration (MHC) in the aqueous phase was required to initiate significant solubilization of 1,2- dichloroethane. Consequent to the increase in solubilization of 1,2-dichloroethane, the mass transfer coefficient was also found to increase with increase in hydrotrope concentration at 303 K . A threshold value of MHC is to be maintained to have an appreciable enhancement in the mass transfer coefficient. The maximum enhancement factor, which is the ratio of the value in the presence and absence of a hydrotrope, has been determined for all sets of experimentations. The performance of Hydrotropes was measured in terms of setschenow constant (Ks) and reported for all Hydrotropes used in this study.
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Separation of m/p-Aminoacetophenone Using Hydrotropy
Hindawi Limited, 2012Co-Authors: M. Dhinakaran, Nagendra N GandhiAbstract:The aqueous solubilities of m/p-aminoacetophenone in different concentrations (0-3.0 mol/L) of Hydrotropes such as diethyl nicotinamide, sodium pseudocumene sulfonate and sodium thiocyanate solutions at different system temperatures (303K to 333K) were studied. The percentage extraction (%E) of m- aminoacetophenone from m/p-aminoacetophenone mixture increases with increase in hydrotrope concentration. A Minimum Hydrotrope Concentration (MHC) in the aqueous phase was required to initiate the significance of the %E of m-aminoacetophenone. Percentage extraction (%E) is the ratio of moles of m-aminoacetophenone extracted in presence and absence of a hydrotrope. The sensitivity and feasibility of the proposed process are examined by carrying out solubilization and equilibrium precipitation experiments with the mixtures of various compositions. The effectiveness of Hydrotropes was measured in terms of Setschenow constant Ks. The extraction data are also fitted in a polynomial equation as the function of hydrotrope concentration. The solubilized material can be recovered by dilution with water
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Effect of Hydrotropes on Solubility and Mass Transfer Coefficient of Methyl Salicylate
Mathematical Models and Methods in Applied Sciences, 2009Co-Authors: M. Dharmendira Kumar And, Nagendra N GandhiAbstract:This paper presents a comprehensive study on the effect of citric acid, sodium benzoate, sodium salicylate, and urea (Hydrotropes) on the solubility and mass transfer coefficient for the extraction of methyl salicylate in water. A Minimum Hydrotropic Concentration (MHC) in the range between 0.20 and 0.90 mol/L was found essential to show a significant increase in the solubility and mass transfer coefficient for the methyl salicylate−water system. The solubility of methyl salicylate has been increased to a maximum value of 22.84 in the presence of citric acid as hydrotrope at concentration of 2.00 mol/L and temperature of 333 K. The maximum enhancement factor for the mass transfer coefficient was found to be 7.88 in the presence of citric acid as hydrotrope at a concentration of 2.00 mol/L at 303 K at 600 rpm. The Setschenow constant, Ks, a measure of the effectiveness of the hydrotrope, has been determined for each case, and the highest value has been observed as 0.743 in the case of citric acid.
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effect of Hydrotropes on the solubility and mass transfer coefficient of benzyl benzoate in water
Journal of Chemical & Engineering Data, 2005Co-Authors: N Meyyappan, Nagendra N GandhiAbstract:This work presents a comprehensive study on the effect of Hydrotropes on the solubility and mass transfer coefficient of benzyl benzoate in water. The solubility studies were performed using Hydrotropes such as tri-sodium citrate, urea, sodium benzoate, and sodium salicylate for various concentrations in the range from (0 to 3.0) mol·L-1 and system temperatures ranging from T = (303 to 333) K. The performance of the Hydrotropes was measured in terms of the Setschenow constant (KS). It was found that the solubility of benzyl benzoate increases with an increase in hydrotrope concentration and also with system temperature. A minimum hydrotrope concentration (MHC) in the aqueous phase was required to initiate significant solubilization of benzyl benzoate. Consequent to the increase in solubilization of benzyl benzoate, the mass transfer coefficient was also found to increase with an increase in hydrotrope concentration. All Hydrotropes used in this work showed an enhancement in the solubility and mass transfe...
Mohmad Shafi Sheikh - One of the best experts on this subject based on the ideXlab platform.
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effect of Hydrotropes on the micellization behavior of sodium dodecyl sulfate sodium dodecyl benzene sulfonate at various temperatures
Journal of Dispersion Science and Technology, 2017Co-Authors: Mohmad Shafi Sheikh, Ahmad Jahan Khanam, Nusrat Shafi, Adil Amin, Malik Abdul RubAbstract:ABSTRACTWith the aim of studying the effect of anionic hydrotrope sodium salicylate and nonionic hydrotrope resorcinol on the micellization behaviors of sodium dodecylsulfate (SDS) as well as sodium dodecylbenzenesulfonate (SDBS), experiments were carried out in aqueous medium at different temperatures using conductivity measurements. Hydrotrope addition leads to decrease in values of critical micelle concentration (cmc). The values of cmc of mixtures were obtained to be lower than the cmc value of ideal and pure component cmc values, which indicate negative deviation with synergistic interaction as confirmed by the negative interaction parameters (βm) values in mixed systems. In addition, the evaluated values of excess free energy of mixing () as well as free energy of micellization (ΔmicG○) are achieved to be negative showing stability of mixed systems.
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analysis of mixed micellar behavior of cationic gemini alkanediyl α ω bis dimethylcetylammonium bromide series with ionic and nonionic Hydrotropes in aqueous medium at different temperatures
Journal of Physical Chemistry B, 2011Co-Authors: Iqrar Ahmad Khan, Ahmad Jahan Khanam, Mohmad Shafi SheikhAbstract:The interaction between cationic symmetrical gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) series (16–s–16, s = 5, 6, abbreviated as G5 and G6) with Hydrotropes (cationic: aniline hydrochloride, para-toluidine hydrochloride, and ortho-toluidine hydrochloride; nonionic: phenol, resorcinol, and pyrogallol) in aqueous medium has been investigated at four different temperatures ranging from 298.15 to 313.15 K. Different physicochemical parameters such as critical micelle concentration (cmc), interaction parameter (βm, an energetic parameter that represents the excess Gibbs free energy of mixing), activity coefficients (fi), mole fraction of hydrotrope in mixed micelles at ideal mixing conditions (X1ideal), excess free energy of mixing (ΔmixGE), standard enthalpy (ΔmicH°), entropy (ΔmicS°), and Gibbs free energy (ΔmicG°) of micellization were evaluated and then intracompared. For further understanding, similar studies were carried out with their conventional counterpart cetyltrimethyl ammonium bromi...
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influence of ionic and nonionic Hydrotropes on micellar behavior of a cationic gemini surfactant butanediyl 1 4 bis dimethylcetylammonium bromide
Journal of Colloid and Interface Science, 2011Co-Authors: Iqrar Ahmad Khan, Ahmad Jahan Khanam, Mohmad Shafi SheikhAbstract:Abstract Micellization of binary systems of a cationic gemini surfactant butanediyl-1,4-bis(dimethylcetylammonium bromide) (16-4-16) and cationic/nonionic Hydrotropes (aniline-hydrochloride, 2-methylanilinehydrochloride, 4-methylanilinehydrochloride, hydroxybenzene, 1,3-benzenediol, benzene-1,2,3-triol) have been studied using a conductometric technique. The critical micelle concentrations (cmc) for different mixing mole fractions at different temperatures have been calculated. To explain and compare the results, theoretical models of Clint, Rubingh and Motomura have been used to obtain the ideal cmc, mixed micelle composition, interaction parameters ( β m ), free energies of micellization, and activity coefficients. The mixtures show nonideal behavior and the interactions between the surfactants and the Hydrotropes are synergistic in nature which is confirmed by high negative β m values and low values of the activity coefficients. Thermodynamic parameters were also obtained from the temperature dependence of the cmc values.
Abdullah M. Asiri - One of the best experts on this subject based on the ideXlab platform.
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solution properties of phenothiazine drug promazine hydrochloride with cationic Hydrotropes in aqueous electrolyte solution at different temperature
Journal of Physical Organic Chemistry, 2016Co-Authors: Malik Abdul Rub, Abdullah M. Asiri, Naved Azum, Mohie E. M. Zayed, Abdulrahman O AlyoubiAbstract:The current work deals with the mixed micellization phenomena of surface active promazine hydrochloride (PMZ) drug with cationic Hydrotropes (para-toluidine hydrochloride and ortho-toluidine hydrochloride) in absence and occurrence of 50 mmol kg−1 NaCl at five different temperature (293.15–313.15 K). PMZ is an amphiphilic phenothiazine drug and employed for the cure of mania and schizophrenia. Conductometry measurement was employed to gain a detailed picture of the interactions between drug and hydrotrope molecules. The experimental data were analyzed according to different mixing models within the outline of the pseudophase separation model. The evaluated values of critical micelle concentration (cmc) were found to be inferior than cmcid values signifying attractive interactions involving the both components in the solutions. NaCl further reduces the cmc of pure amphiphiles and their mixed systems as a result of screening of the electrostatic repulsion between the polar head groups. The micellar mole fractions (X1) of Hydrotropes evaluated by various proposed models were constantly more than ideal values ( ) signifying high involvements of hydrotrope in mixed micelles. Activity coefficients ( and ) were always below one in all cases signifying synergism in mixed micelles. Thermodynamic parameters favor the process of micellization which is found to be entropy driven. The negative values of free energies of mixing demonstrated the stability of the mixed systems of drug and hydrotrope. Copyright © 2016 John Wiley & Sons, Ltd.
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clouding phenomenon of amphiphilic drug promazine hydrochloride solutions influence of pharmaceutical excipients
Journal of Industrial and Engineering Chemistry, 2015Co-Authors: Naved Azum, Dileep Kumar, Farah Khan, Abdullah M. AsiriAbstract:Abstract Various additives viz. Hydrotropes, bile salts, fatty acid and cyclodextrin effect on the cloud point (CP) behavior of amphiphilic drug promazine hydrochloride (PMZ) in 1 mmol dm−3 14-4-14 + 10 mmol dm−3 sodium phosphate (SP) buffer solutions have been investigated in the present study. These various additives are usually used as pharmaceutical excipients. The additives like anionic Hydrotropes, bile salts and fatty acid salts increase the CP of PMZ, when added in low concentrations, whereas at high concentration, decrease it. Cationic and nonionic Hydrotropes increase the CP of PMZ solutions at all concentration. Cyclodextrin behave like simple sugar is found to decrease the CP of the drug solutions at all concentrations. Gemini surfactant (14-4-14) has been found a better surfactant that can prevent clouding under physiological condition. It can thus be used as a drug-carrier system that increases the storage stability. The thermodynamic parameters are also evaluated: where Δ G c o is found to be negative and Δ H c o and T Δ S c o values are negative as well as positive depending upon type and nature of additive.
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Investigation of Micellar and Phase Separation Phenomenon of the Amphiphilic Drug Amitriptyline Hydrochloride with Cationic Hydrotropes
Journal of Solution Chemistry, 2013Co-Authors: Malik Abdul Rub, Abdullah M. Asiri, Naved Azum, Anish Khan, Aftab Aslam Parwaz Khan, Sher Bahadar Khan, Kabir-ud-dinAbstract:Micellization and phase separation of the amphiphilic drug amitriptyline hydrochloride (AMT) in the absence and presence of cationic Hydrotropes (aniline hydrochloride, para-toluidine hydrochloride, and ortho-toluidine hydrochloride) have been investigated in the present study. The experimental critical micelle concentration (cmc) values are lower than cmcid values (cmcid is the cmc value at ideal mixing state), indicating attractive interactions between the two components (drug and hydrotrope) in mixed micelles. The bulk behaviors were investigated using the different theoretical models of Clint, Rubingh, Motomura, and Rodenas for comparison of the results of different binary combinations of the drug and Hydrotropes. Synergistic interactions were confirmed in all binary combinations at all temperatures, which increase with increasing concentration of Hydrotropes. Activity coefficients (f1 and f2) were found to be consistently less than unity indicating nonideality in the systems. At a fixed drug concentration (50 mmol·dm−3) and pH (6.7), the Hydrotropes showed a continuous increase in the cloud point. Thermodynamic parameters were also evaluated and discussed in detail.
Mikhail A. Anisimov - One of the best experts on this subject based on the ideXlab platform.
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dual action of Hydrotropes at the water oil interface
Journal of Physical Chemistry C, 2017Co-Authors: Andrei A. Novikov, Jeffery B. Klauda, Anton P. Semenov, Vladimir N. Kuryakov, Viviana Monjegalvan, Mikhail A. AnisimovAbstract:Hydrotropes are substances containing small amphiphilic molecules, which increase solubility of nonpolar (hydrophobic) substances in water. Hydrotropes may form dynamic clusters (less or about 1 ns lifetime) with water molecules; such clusters can be viewed as “pre-micelles” or as “micellar-like” structural fluctuations. We present the results of experimental and molecular dynamics (MD) simulation studies of interfacial phenomena and liquid–liquid equilibrium in the mixtures of water and cyclohexane with the addition of a typical nonionic hydrotrope, tertiary butanol. The interfacial tension between the aqueous and oil phases was measured by Wilhelmy plate and spinning drop methods with overlapping conditions in excellent agreement between techniques. The correlation length of the concentration fluctuations, which is proportional to the thickness of the interface near the liquid–liquid critical point, was measured by dynamic light scattering. In addition, we studied the interfacial tension and water–oil i...
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Dual Action of Hydrotropes at the Water/Oil Interface
2017Co-Authors: Andrei A. Novikov, Jeffery B. Klauda, Anton P. Semenov, Viviana Monje-galvan, Vladimir N. Kuryakov, Mikhail A. AnisimovAbstract:Hydrotropes are substances containing small amphiphilic molecules, which increase solubility of nonpolar (hydrophobic) substances in water. Hydrotropes may form dynamic clusters (less or about 1 ns lifetime) with water molecules; such clusters can be viewed as “pre-micelles” or as “micellar-like” structural fluctuations. We present the results of experimental and molecular dynamics (MD) simulation studies of interfacial phenomena and liquid–liquid equilibrium in the mixtures of water and cyclohexane with the addition of a typical nonionic hydrotrope, tertiary butanol. The interfacial tension between the aqueous and oil phases was measured by Wilhelmy plate and spinning drop methods with overlapping conditions in excellent agreement between techniques. The correlation length of the concentration fluctuations, which is proportional to the thickness of the interface near the liquid–liquid critical point, was measured by dynamic light scattering. In addition, we studied the interfacial tension and water–oil interfacial profiles by MD simulations of a model representing this ternary system. Both experimental and simulation studies consistently demonstrate a spectacular crossover between two limits in the behavior of the water–oil interfacial properties upon addition of the hydrotrope: at low concentrations the hydrotrope acts as a surfactant, decreasing the interfacial tension by adsorption of hydrotrope molecules on the interface, while at higher concentrations it acts as a cosolvent with the interfacial tension vanishing in accordance with a scaling power-law upon approach to the liquid–liquid critical point. It is found that the relation between the thickness of the interface and the interfacial tension follows a scaling law in the entire range of interfacial tensions, from a “sharp” interface in the absence of the hydrotrope to a “smooth” interface near the critical point. We also demonstrate the generic nature of the dual behavior of Hydrotropes by comparing the studied ternary system with systems containing different hydrocarbons and Hydrotropes
