Effect of ciprofloxacin hydrochloride on the micellization in double tailed surfactants aqueous solution

The effects of ciprofloxacin hydrochloride (CF) on the micellization of double tailed surfactants in aqueous solutions, aerosol-OT (AOT) and didodecyldimethylammonium bromide (DDAB), were studied by surface tension and UV spectra measurements. The results from surface tension measurements demonstrated that CF could decrease the equilibrium values of the surface tension and critical micelle concentration (cmc) of AOT, but increase that of DDAB. Their standard thermodynamic functions of micellization, Delta G(m)degrees, Delta H-m degrees, and Delta S-m degrees, have been obtained in aqueous solutions at 298K. The further conclusions were got from UV spectrophotometry. It is demonstrated that CF is solubilized close to the interface of micelle/water for DDAB cationic surfactant. However, CF could be localized in the palisade layer of the AOT micelle.