Physico-chemical study of the interaction between levofloxacin hemihydrate Drug with Cetylpyridinium chloride in aqueous medium: conductometric and spectrophotometric investigation

Abstract

Herein, the interaction between levofloxacin hemihydrate (LFH), a fluoroquinolone antibiotic drug, and cetylpyridinium chloride (CPC), a cationic surfactant, has been studied by applying conductometric and spectrophotometric techniques at various temperatures. The binding constant of LFH to various types of micelles has also been calculated by means of the Benesi-Hildebrand Equation. (CPC+LFH) mixed system exhibits lower critical micelle concentration (cmc) values in magnitude compared to the pure CPC in aqueous solution at a particular temperature as confirmed by the conductometric measurements. The profound change in the cmc values of the (CPC+LFH) mixtures by varying the concentration of LFH signify the synergistic (attractive) interaction between CPC and LFH. In addition, The negative values of standard free energy demonstrate the stability of the (CPC+LFH) mixture. Furthermore, the other thermodynamic parameters such as the standard enthalpy and standard entropy data suggest the existence of hydrophobic interaction between LFH and surfactants.