Effect of temperature and salts on the interaction of cetyltrimethylammonium bromide with ceftriaxone sodium trihydrate drug

Interaction of the third-generation cephalosporin antibiotic drug ceftriaxone sodium trihydrate (CFT) with a cationic conventional surfactant cetyltrimethylammonium bromide (CTAB) has been carried out by conductometric technique in water and in the presence of various salts such as NaCl, Na2SO4 and Na3PO4 at varying temperatures with gaps of T = 5 K. Two critical micelle concentrations (c*1 and c*2) were obtained for (CFT + CTAB) mixtures in all the cases. The change of c⁎ values of CTAB due to the addition of CFT is indicative of the interaction between CFT and CTAB. For the (CFT + CTAB) mixed system, the values of c⁎ are higher in magnitude in contrast to that of pure CTAB in aqueous solution at a particular temperature. Both the c⁎ values for (CFT + CTAB) mixed system in the presence of different salts are lower in magnitude as compared to aqueous medium which means addition of salt favors the micellization of (CFT + CTAB) mixed system. The ∆ G0m values are obtained to be negative in all the cases. The heat capacity (ΔC0p.m.), transfer energy (∆ G0m.tr.), transfer enthalpy (ΔH0m.tr.) and transfer heat capacities (ΔC0p.m.tr.) were also determined and discussed as an extension of the usual thermodynamic quantities of micellization.