Influence of electrolytes/urea on the interaction of tetradecyltrimethylammonium bromide and antibiotic levofloxacin hemihydrate drug

A study of the interaction of tetradecyltrimethylammonium bromide (TTAB) and levofloxacin hemihydrate (LFH) mixtures has been studied by conductivity measurement method in aqueous medium and in the presence of inorganic electrolyte (KNO3 and K2SO4)/urea at various temperatures (298.15-318.15 K) with typical gap of 5 K. For pure TTAB along with drug-TTAB mixture in aqueous as well as in salts/urea solution, a single critical micelle concentration (CMC) was noticed. The CMC values for LFH-TTAB mixtures in the presence of salts exhibited lower in magnitude as compared to aqueous solution. The Delta G(m) values were found to be negative in the entire cases signifying the spontaneous formation of micelles. Both Delta H-m and Delta S-m indicated that hydrophobic as well as electrostatic interactions were enhanced in the presence of electrolytes compared to an aqueous solution. Other thermodynamics variables such as transfer enthalpy (Delta H-m.tr), transfer energy (Delta G(m.tr)), and transfer entropy (Delta S degrees(m.tr)) were evaluated and explained thoroughly.