Modulation in Aggregation Behavior of Cationic Surfactant in Presence of Fluoroquinolone Drug: A Physicochemical Approach

Abstract

AbstractMeasurements of density, speed of sound, conductivity, and fluorescence spectroscopy have been carried out to study the interactions between cationic surfactant cetyltrimethylammonium bromide in an aqueous solution of the fluoroquinolone drug at different concentrations and temperatures. Volumetric and compressibility parameters, such as apparent molar volumes ( V φ), isentropic compressibility ( κ s), and apparent molar isentropic compressibility (κ φ, s), have been obtained from density and speed of sound. The critical micelle concentration (CMC) of cetyltrimethylammonium bromide (CTAB) is found to decrease with an increase in [antibiotic drug] and increase with an increase in temperature, accounting for the fact that hydrophilic dehydration plays a decisive role for micellization to take place. The various thermodynamic parameters indicate the spontaneity of micellization in the presence of drug moiety. The CMC values have been calculated using pyrene as a fluorescent probe at room temperature, and a good qualitative correlation is found to exist well with the CMC values determined using speed of sound and conductivity measurements.