Conductivity, cloud point and molecular dynamics investigations of the interaction of surfactants with ciprofloxacin hydrochloride drug: Effect of electrolytes

Abstract

Multiple methods (conductivity, cloud point (CP), and molecular dynamics simulation) were applied to evaluate the interaction of tetradecyltrimethylammonium bromide (TTAB) and Tween 80 (Tw 80) with ciprofloxacin hydrochloride (CFH) in electrolytes solution. From the phase separation technique, values of cloud point (CP) of Tw 80 + CFH mixture were evaluated and noticed to decrease through the increase of CFH content. The free energy of clouding (∆Gco) values of Tw 80 + CFH mixture were noticed as positive in whole cases which indicates the non-spontaneity of the clouding phenomenon. Other thermodynamic properties and thermodynamic parameters of transfer for Tw 80 + CFH mixture in salts media were also evaluated and explained in detail. From conductivity measurements, micellar parameters-critical micelle concentration (cmc), the fraction of counterion dissociation (ɑ), and thermodynamic parameters of the studied systems have been evaluated. The cmc values were found to be dependent on the temperature and concentration of salt. In salt solution (NaCl), the cmc values of TTAB+CFH mixtures decrease with enhancing NaCl concentration viewing the start of micelle formation at inferior TTAB concentration. The values of ∆Hmo as well as ∆Smo prove the presence of hydrophobic and electrostatic interaction between drug and surfactant. Herein, the molecular dynamics simulation method was also taken into consideration in exposing the mechanism of CFH-surfactants interactions happening at the atomic level, which exposed a good comparison with the experimental outcomes. Herein, the obtained results implied that conventional nonionic surfactant may possibly work as a efficient drug delivery vehicle for antibiotics, enhancing their bioavailability.