LAUSR

Abstract The interaction between sodium dodecyl sulfate (SDS) and an antibiotic drug, ciprofloxacin hydrochloride (CPFH) has been carried out by conductometric measurement at various temperatures from 298.15 K to 318.15 K. The critical micelle concentration (cmc) values of SDS/SDS+CPFH mixture were attained to be reduced in the electrolytes medium. The effect on the cmc reduction is higher in case of ammonium carbonate than ammonium chloride. The cmc values of SDS/SDS+CPFH mixture follow U-shaped behavior with temperature in water and ammonium chloride and reversed U-shaped in ammonium carbonate solution. In the existence of CPFH, the cmc of SDS reduces in aqueous medium but enhances in the electrolytes medium. The extent of micelle ionization (α) was found to be enhanced with the increase of concentration of CPFH in aqueous medium and in ammonium chloride medium at a lower temperature. The α values follow inverted U-shaped in ammonium carbonate medium. The estimated values of Δ G m o for distinct SDS, as well as SDS+CPFH mixtures, were obtained to be negative in entire cases illustrating the spontaneity of micellization. The magnitudes of Δ H m o , Δ S m o and thermodynamic parameters of transfer have been evaluated and discussed in details.