115 research outputs found
Effect of KCl on the micellization and clouding phenomenon of the amphiphilic phenothiazine drug promethazine hydrochloride: some thermodynamic properties
No full textIn the present paper, we report the micellization at different fixed temperatures [(293.15, 303.15, 313.15, and 323.15) K] and the clouding behavior of the phenothiazine drug 10-[2-(dimethylamino)propyl]phenothiazine hydrochloride (promethazine hydrochloride, PMT) in the absence and presence of KCl. The critical micelle concentration (cmc) of PMT was measured by the conductivity method. The cmc values decrease with increasing the KCl concentration, whereas with increasing temperature, the cmc values increase. The thermodynamic parameters, namely, the standard Gibbs energy (ΔmG°), standard enthalpy (ΔmH°), and standard entropy (ΔmS°) of micellization of PMT were evaluated, and they indicate greater stability of the PMT solution in the presence of KCl. PMT shows phase separation also. The cloud point (CP) of PMT decreases with increasing pH because of deprotonation of the drug molecules. The CP values increase with increasing KCl as well as PMT concentration because of micellar growth. Furthermore, the thermodynamic parameters were evaluated at the CP
Micellization and clouding phenomenon of amphiphilic antidepressant drug amitriptyline hydrochloride: effect of KCl
No full textIn the present study, we report the micellization and clouding behavior of an amphiphilic antidepressant drug viz., amitriptyline hydrochloride (AMT) at different fixed temperatures and KCl concentrations in aqueous solutions. The critical micelle concentration (cmc) of AMT, as measured by conductivity method, increases with increasing temperature and decreasing with KCl concentration. The thermodynamic parameters viz., standard Gibbs energy (ΔG0m ), standard enthalpy (ΔH0m), and standard entropy (ΔS0m) of micellization of AMT are evaluated. The values clearly indicate more stability of the AMT solution in presence of KCl. Like surfactant, AMT also shows phase separation behavior. The cloud point (CP) of AMT in water decreases with increase in pH of the medium because of the deprotonation of the drug molecule. The CP values increase with increasing KCl concentration and AMT concentrations, clearly indicating the micellar growth at higher concentration. Furthermore, for better understanding of the behavior of drug molecule in water, we evaluated various thermodynamic parameters of the above drug molecule at CP
Self-association and mixed micellization of an amphiphilic antidepressant drug, 5-[3-(Dimethylamino)propyl]-10,11-dihydro-5H-dibenz[b,f]azepine hydrochloride and a nonionic surfactant, poly(ethylene glycol) t-octylphenyl ether: Evaluation of thermodynamics
No full textExploring the Potential of PEG-Based Deep Eutectic Solvents as a Sustainable Alternative for Extraction of Biological Macromolecules Bovine Serum Hemoglobin
No full textEffect of Additives on Self-Association and Clouding Phenomena of Various Surface-Active Drugs
No full textDensity, dynamic viscosity, and kinematic viscosity studies of aqueous solution of a cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16): Influence of electrolytes and temperature
No full textThe density, dynamic viscosity and kinematic viscosity of protic and aprotic polar solvent (pure and mixed) systems: An experimental and theoretical insight of thermophysical properties
No full textWe report herein the thermophysical properties of pure protic and aprotic polar solvents (water, dimethyl sulfoxide and N,N-dimethyl formamide) and their mixed (binary and ternary) systems. The experimental density (ρ) and viscosity (η) were determined for these systems by varying temperature range from 293.15 K to 343.15 K. The excess properties (viz., excess molar volumes (VE), excess thermal expansion coefficient (αE), viscosity deviation (Δη) and excess Gibb's free energy (ΔGE) for viscous flow) were computed for mixed systems from experimental values. The excess properties of the mixed systems show clearly a non-ideal behaviour. Especially, a mixture of water with aprotic polar component show better thermophysical properties than pure systems. The pure (DMF) system shows increasing dynamic viscosity values at higher temperature region. Both the binary as well as ternary mixed systems show maximum activation energy (Ea) in the presence of water depicts their thermal stability of the mixed systems. The thermal expansion coefficient (α) also revealed increase in the thermal behaviour for the protic-aprotic systems. In addition to that, thermodynamic parameters are also evaluated for better understanding of thermal stability
The density, dynamic viscosity and kinematic viscosity of protic polar solvents (pure and mixed systems) studies: A theoretical insight of thermophysical properties
No full textThe densities (ρ) and viscosities (η) have been studied for pure and mixed systems of protic polar solvents water, methanol, ethanol and propan-1-ol for entire composition range at temperature from 293 K to 343 K in 5 K intervals at atmospheric pressure. With increase in temperature the density values as well as the dynamic viscosity values were decrease. The obtained values are used to calculate the excess properties such as excess molar free volume (VE), thermal expansion coefficient (α), excess thermal expansion coefficient (αE), viscosity deviation (Δη) and excess Gibb's free energy (ΔG⁎E) for the activation of viscous flow for mixed systems. The calculated excess properties of binary mixtures were correlated with Redlich-Kister type polynomial equation by least square regression method and fitting parameters were found for all binary systems. The temperature dependence of viscosities for mixed systems has been explained using Arrhenius type equation of Newtonian classic solvents and Eyring transition state equation. The thermodynamic parameters were also evaluated for mixed systems which show the thermal stability of system
Thermodynamics of the Amphiphilic Drug, Amitriptyline Hydrochloride-Surfactant/Polymer Systems at the Cloud Point
No full textHerein, we report the energetics of clouding in amphiphilic drug, amitriptyline hydrochloride (AMT-a tricyclic antidepressant drug), in the presense of surfactants and polymers. Surfactants/polymers are extensively used in drug delivery as drug carriers. The cloud point (CP) of an amphiphile can be considered as the limit of its solubility. The clouding components release their solvated water and separate out from the solution. Hence, the standard Gibbs free energy change of solubilization (ΔG0s) is evaluated from the relation ΔG0s=-RTlnXs. For all the additives, ΔG0s is found to be positive. However, ΔH0s and TΔS0s 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
- …
