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Md Sayem Alam - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic studies on mixed micellization of amphiphilic drug amitriptyline hydrochloride and nonionic surfactant triton x 100
Journal of Molecular Liquids, 2012Co-Authors: Md Sayem Alam, A B MandalAbstract:Abstract In the present work, we report the surface properties and mixed micellization of a tricyclic antidepressant drug amitriptyline hydrochloride (AMT) with nonionic surfactant poly(ethylene glycol) t- octylphenyl ether (TX-100) using surface tension measurements. The surface properties in aqueous solution of AMT drug in the absence and presence of TX-100 are presented. The critical micelle concentration (cmc), maximum surface excess concentration at the air/water interface ( Γ max ) and the minimum area per surfactant molecule at the air/water interface ( A min ) parameters are evaluated. Γ max increases and cmc as well as A min decrease with increasing concentration (mole fraction) of the additive (TX-100). We also report the thermodynamics of AMT in the absence and presence of TX-100 and evaluated Gibbs energies (viz., at air/water interface (G min (s) ), the Standard Gibbs Energy change of micellization (Δ mic G 0 ), the Standard Gibbs Energy change of adsorption (Δ ads G 0 ), the excess free Energy change of micellization (ΔG ex m )).
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thermodynamics studies on tyrosine hydantoin drug cetyltrimethylammonium bromide mixed micellar system
Colloids and Surfaces B: Biointerfaces, 2011Co-Authors: Lalan K Tiwary, A B Mandal, Md Sayem Alam, Sathiah ThennarasuAbstract:In the present paper, we report the micellization, aggregation behavior and thermodynamics of a cationic surfactant viz. cetyltrimethylammonium bromide (CTAB) in absence and presence of tyrosine-hydantoin (TH) drug. The solution behavior of the mixture of CTAB and TH drug has been determined using conductivity, surface tension, UV-visible and fluorescence spectroscopic methods. A strong interaction between the two amphiphiles is indicated from the above measurements. The critical micelle concentration (cmc) of CTAB is found to decrease with increase in the amount of TH in the mixture. The cmc values obtained by these methods are in good agreement with each other. The critical micelle concentration, aggregation number and Standard free Energy changes of aggregation of the surfactant (CTAB) in aqueous solution in absence and presence of TH are evaluated at different temperatures (294, 303 and 318K). The aggregation number is obtained by the steady-state fluorescence spectroscopic method. Thermodynamic parameters (the Standard Gibbs Energy change of micellization, ΔG°(m), the Standard enthalpy change of micellization, ΔH°(m), the Standard entropy change of micellization, ΔS°(m), the Standard Gibbs (transfer) Energy, (ΔG°(m))(tr)' , and the excess free Energy change of micellization, ΔG(ex)) have been evaluated. The negative values of Standard Gibbs Energy change indicate spontaneous micellization and synergism. The interaction parameter, β(m), activity coefficients (f(1), f(2)) have been evaluated, and using these data we evaluated excess Gibbs energies, which indicate the spontaneity and the stability of the mixed micelles.
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amphiphilic drug promethazine hydrochloride additive systems evaluation of thermodynamic parameters at cloud point
Journal of Chemical & Engineering Data, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:At the cloud point (CP, where phase separation occurs), the thermodynamic properties of aqueous buffer solution of the amphiphilic phenothiazine drug promethazine hydrochloride (PMT) are calculated in the presence of various additives (viz., alcohols, surfactants, and polymers). PMT undergoes clouding phenomena, which depend upon the physicochemical conditions (e.g., concentration, pH, temperature, etc.). As the clouding components release their solvated water, they separate out from the solution. Therefore, the CP of an amphiphile can be considered the limit of its solubility. Herein, we report the thermodynamics of clouding in PMT in the presence of additives. The Standard Gibbs Energy change of solubilization (ΔsG0) for all of the additives is found to be positive. However, the Standard enthalpy change (ΔsH0) and the product of temperature and the Standard entropy change (TΔsS0) values are negative as well as positive depending upon the type and nature of the additive. The results are discussed on the ...
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evaluation of thermodynamic parameters of amphiphilic tricyclic antidepressant drug imipramine hydrochloride additive systems at the cloud point
Colloids and Surfaces B: Biointerfaces, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:Abstract Cloud point (CP) of an amphiphile can be considered as the limit of its solubility as it phase separates at temperatures above the CP. The clouding components release their solvated water and separate out from the solution. In the present paper, we report the thermodynamics of clouding in amphiphilic drug, imipramine hydrochloride (IMP—a tricyclic antidepressant drug), in the presence of additives (viz., alcohols and surfactants). Surfactants are extensively used in drug delivery as drug carriers. For all cases the Standard Gibbs Energy change of solubilization ( Δ G s 0 ) is evaluated and, found to be positive. However, the Standard enthalpy change ( Δ H s 0 ), and the product of Standard entropy change and temperature ( T Δ S s 0 ) values are found negative as well as positive. These values are depending upon the type and nature of the additive, and the results are discussed on the basis of these factors.
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thermodynamics at the cloud point of phenothiazine drug chlorpromazine hydrochloride additive systems
Journal of Chemical & Engineering Data, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:An amphiphilic drug chlorpromazine hydrochloride (CPZ), a phenothiazine with neuroleptic activity, undergoes clouding phenomena, which depend upon the physicochemical conditions (e.g., concentration, pH, temperature, etc.). The clouding components release their solvated water and separate out from the solution. Therefore, the cloud point (CP) of an amphiphile can be considered as the limit of its solubility. Herein, we report the energetics of clouding in CPZ in the presence of additives (viz., alcohols, surfactants, and polymers). The Standard Gibbs Energy change of solubilization (ΔG 0 s ) for all of the additives is found to be positive. However, the Standard enthalpy change (ΔH 0 s ) and the product of the temperature and the Standard entropy change (TΔS 0 s ) values are negative as well as positive, depending upon the type and nature of the additive, and the results are discussed on the basis of these factors.
A B Mandal - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic studies on mixed micellization of amphiphilic drug amitriptyline hydrochloride and nonionic surfactant triton x 100
Journal of Molecular Liquids, 2012Co-Authors: Md Sayem Alam, A B MandalAbstract:Abstract In the present work, we report the surface properties and mixed micellization of a tricyclic antidepressant drug amitriptyline hydrochloride (AMT) with nonionic surfactant poly(ethylene glycol) t- octylphenyl ether (TX-100) using surface tension measurements. The surface properties in aqueous solution of AMT drug in the absence and presence of TX-100 are presented. The critical micelle concentration (cmc), maximum surface excess concentration at the air/water interface ( Γ max ) and the minimum area per surfactant molecule at the air/water interface ( A min ) parameters are evaluated. Γ max increases and cmc as well as A min decrease with increasing concentration (mole fraction) of the additive (TX-100). We also report the thermodynamics of AMT in the absence and presence of TX-100 and evaluated Gibbs energies (viz., at air/water interface (G min (s) ), the Standard Gibbs Energy change of micellization (Δ mic G 0 ), the Standard Gibbs Energy change of adsorption (Δ ads G 0 ), the excess free Energy change of micellization (ΔG ex m )).
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thermodynamics studies on tyrosine hydantoin drug cetyltrimethylammonium bromide mixed micellar system
Colloids and Surfaces B: Biointerfaces, 2011Co-Authors: Lalan K Tiwary, A B Mandal, Md Sayem Alam, Sathiah ThennarasuAbstract:In the present paper, we report the micellization, aggregation behavior and thermodynamics of a cationic surfactant viz. cetyltrimethylammonium bromide (CTAB) in absence and presence of tyrosine-hydantoin (TH) drug. The solution behavior of the mixture of CTAB and TH drug has been determined using conductivity, surface tension, UV-visible and fluorescence spectroscopic methods. A strong interaction between the two amphiphiles is indicated from the above measurements. The critical micelle concentration (cmc) of CTAB is found to decrease with increase in the amount of TH in the mixture. The cmc values obtained by these methods are in good agreement with each other. The critical micelle concentration, aggregation number and Standard free Energy changes of aggregation of the surfactant (CTAB) in aqueous solution in absence and presence of TH are evaluated at different temperatures (294, 303 and 318K). The aggregation number is obtained by the steady-state fluorescence spectroscopic method. Thermodynamic parameters (the Standard Gibbs Energy change of micellization, ΔG°(m), the Standard enthalpy change of micellization, ΔH°(m), the Standard entropy change of micellization, ΔS°(m), the Standard Gibbs (transfer) Energy, (ΔG°(m))(tr)' , and the excess free Energy change of micellization, ΔG(ex)) have been evaluated. The negative values of Standard Gibbs Energy change indicate spontaneous micellization and synergism. The interaction parameter, β(m), activity coefficients (f(1), f(2)) have been evaluated, and using these data we evaluated excess Gibbs energies, which indicate the spontaneity and the stability of the mixed micelles.
Asit Baran Mandal - One of the best experts on this subject based on the ideXlab platform.
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amphiphilic drug promethazine hydrochloride additive systems evaluation of thermodynamic parameters at cloud point
Journal of Chemical & Engineering Data, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:At the cloud point (CP, where phase separation occurs), the thermodynamic properties of aqueous buffer solution of the amphiphilic phenothiazine drug promethazine hydrochloride (PMT) are calculated in the presence of various additives (viz., alcohols, surfactants, and polymers). PMT undergoes clouding phenomena, which depend upon the physicochemical conditions (e.g., concentration, pH, temperature, etc.). As the clouding components release their solvated water, they separate out from the solution. Therefore, the CP of an amphiphile can be considered the limit of its solubility. Herein, we report the thermodynamics of clouding in PMT in the presence of additives. The Standard Gibbs Energy change of solubilization (ΔsG0) for all of the additives is found to be positive. However, the Standard enthalpy change (ΔsH0) and the product of temperature and the Standard entropy change (TΔsS0) values are negative as well as positive depending upon the type and nature of the additive. The results are discussed on the ...
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evaluation of thermodynamic parameters of amphiphilic tricyclic antidepressant drug imipramine hydrochloride additive systems at the cloud point
Colloids and Surfaces B: Biointerfaces, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:Abstract Cloud point (CP) of an amphiphile can be considered as the limit of its solubility as it phase separates at temperatures above the CP. The clouding components release their solvated water and separate out from the solution. In the present paper, we report the thermodynamics of clouding in amphiphilic drug, imipramine hydrochloride (IMP—a tricyclic antidepressant drug), in the presence of additives (viz., alcohols and surfactants). Surfactants are extensively used in drug delivery as drug carriers. For all cases the Standard Gibbs Energy change of solubilization ( Δ G s 0 ) is evaluated and, found to be positive. However, the Standard enthalpy change ( Δ H s 0 ), and the product of Standard entropy change and temperature ( T Δ S s 0 ) values are found negative as well as positive. These values are depending upon the type and nature of the additive, and the results are discussed on the basis of these factors.
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thermodynamics at the cloud point of phenothiazine drug chlorpromazine hydrochloride additive systems
Journal of Chemical & Engineering Data, 2010Co-Authors: Md Sayem Alam, Asit Baran MandalAbstract:An amphiphilic drug chlorpromazine hydrochloride (CPZ), a phenothiazine with neuroleptic activity, undergoes clouding phenomena, which depend upon the physicochemical conditions (e.g., concentration, pH, temperature, etc.). The clouding components release their solvated water and separate out from the solution. Therefore, the cloud point (CP) of an amphiphile can be considered as the limit of its solubility. Herein, we report the energetics of clouding in CPZ in the presence of additives (viz., alcohols, surfactants, and polymers). The Standard Gibbs Energy change of solubilization (ΔG 0 s ) for all of the additives is found to be positive. However, the Standard enthalpy change (ΔH 0 s ) and the product of the temperature and the Standard entropy change (TΔS 0 s ) values are negative as well as positive, depending upon the type and nature of the additive, and the results are discussed on the basis of these factors.
Margarida Costa F Gomes - One of the best experts on this subject based on the ideXlab platform.
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solubility of carbon dioxide ethane methane oxygen nitrogen hydrogen argon and carbon monoxide in 1 butyl 3 methylimidazolium tetrafluoroborate between temperatures 283 k and 343 k and at pressures close to atmospheric
The Journal of Chemical Thermodynamics, 2006Co-Authors: Johan Jacquemin, Pascale Husson, Margarida Costa F Gomes, Vladimir MajerAbstract:Abstract Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4] – a room temperature ionic liquid – are reported as a function of temperature between 283 K and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble gas with mole fraction solubilities of the order of 10−2. Ethane and methane are one order of magnitude more soluble than the other five gases that have mole fraction solubilities of the order of 10−4. Hydrogen is the less soluble of the gaseous solutes studied. From the variation of solubility, expressed as Henry’s law constants, with temperature, the partial molar thermodynamic functions of solvation such as the Standard Gibbs Energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry’s law constants from appropriate smoothing equations is of 1%.
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low pressure solubilities and thermodynamics of solvation of eight gases in 1 butyl 3 methylimidazolium hexafluorophosphate
Fluid Phase Equilibria, 2006Co-Authors: Johan Jacquemin, Pascale Husson, Vladimir Majer, Margarida Costa F GomesAbstract:Abstract Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6] – a room temperature ionic liquid – are reported as a function of temperature between 283 and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble and hydrogen is the least soluble of the gases studied with mole fraction solubilities of the order of 10−2 and 10−4, respectively. All the mole fraction solubilities decrease with temperature except for hydrogen for which a maximum is observed at temperatures close to 310 K. From the variation of solubility, expressed as Henry's law constants, with temperature, the partial molar thermodynamic functions of solvation such as the Standard Gibbs Energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is better than ±1%.
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solubilities of oxygen and carbon dioxide in butyl methyl imidazolium tetrafluoroborate as a function of temperature and at pressures close to atmospheric pressure
Journal of Chemical & Engineering Data, 2003Co-Authors: Pascale Hussonborg, And Vladimir Majer, Margarida Costa F GomesAbstract:The measurements of the solubility of carbon dioxide and oxygen in a commonly used room temperature ionic liquid, butyl methyl imidazolium tetrafluoroborate ([bmim][BF4]), are reported as a function of temperature between 303 K and 343 K and at pressures close to atmospheric. A new experimental apparatus, based on a saturation method, is presented. The solubility is expressed in terms of molarities, mole fractions, and Henry's law coefficients. From their variation with temperature, the partial molar thermodynamic functions of solvation such as the Standard Gibbs Energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law coefficients from appropriate smoothing equations, is 4% for oxygen and 3% for carbon dioxide.
Vladimir Majer - One of the best experts on this subject based on the ideXlab platform.
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solubility of carbon dioxide ethane methane oxygen nitrogen hydrogen argon and carbon monoxide in 1 butyl 3 methylimidazolium tetrafluoroborate between temperatures 283 k and 343 k and at pressures close to atmospheric
The Journal of Chemical Thermodynamics, 2006Co-Authors: Johan Jacquemin, Pascale Husson, Margarida Costa F Gomes, Vladimir MajerAbstract:Abstract Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4] – a room temperature ionic liquid – are reported as a function of temperature between 283 K and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble gas with mole fraction solubilities of the order of 10−2. Ethane and methane are one order of magnitude more soluble than the other five gases that have mole fraction solubilities of the order of 10−4. Hydrogen is the less soluble of the gaseous solutes studied. From the variation of solubility, expressed as Henry’s law constants, with temperature, the partial molar thermodynamic functions of solvation such as the Standard Gibbs Energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry’s law constants from appropriate smoothing equations is of 1%.
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low pressure solubilities and thermodynamics of solvation of eight gases in 1 butyl 3 methylimidazolium hexafluorophosphate
Fluid Phase Equilibria, 2006Co-Authors: Johan Jacquemin, Pascale Husson, Vladimir Majer, Margarida Costa F GomesAbstract:Abstract Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6] – a room temperature ionic liquid – are reported as a function of temperature between 283 and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble and hydrogen is the least soluble of the gases studied with mole fraction solubilities of the order of 10−2 and 10−4, respectively. All the mole fraction solubilities decrease with temperature except for hydrogen for which a maximum is observed at temperatures close to 310 K. From the variation of solubility, expressed as Henry's law constants, with temperature, the partial molar thermodynamic functions of solvation such as the Standard Gibbs Energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is better than ±1%.
