Thermodynamic and acoustic studies of quercetin with sodium dodecyl sulfate in hydro-ethanolic solvent systems: A flavonoid-surfactant interaction study

Abstract

The thermodynamic and acoustic studies for well-known flavonoid; quercetin with an anionic surfactant sodium dodecyl sulfate (SDS) have been reported. The properties of micellar systems exhibiting various hydrophobic and hydrophilic interactions have been studied. The studies were performed in four different hydro-ethanolic concentrations i.e., aqueous, 30% v/v, 70% v/v and absolute ethanol at five different temperatures (293.15 K to 313.15 K with a difference of 5 K). Various parameters such as conductivity (κ), density (ρ), ultrasonic sound velocity (μ) and relative viscosity (ηr) were determined and resulting data was used to calculate the thermodynamic and acoustic parameters, namely, standard enthalpy change (ΔHom), standard entropy change (ΔSom), standard Gibbs energy change (ΔGom) of micellization, apparent molar volume (ϕv) and apparent molar compressibility (ϕk). Moreover, 1H NMR spectroscopic analysis of SDS and micelles was performed in order to confirm the location of quercetin in micellar structure of surfactant. These studies are helpful in investigating the extent of hydrophobic interactions within the system which might be utilized in determining a stable flavonoid-surfactant concentration in preparing pharmaceutical formulations.