Effect of temperature and salt/alcohol on the interaction of tetradecyltrimethylammonium bromide/Triton X-100 with moxifloxacin hydrochloride: A multitechnique approach

Interaction of moxifloxacin hydrochloride (MFH) with tetradecyltrimethylammonium bromide (TTAB) along with Triton X-100 (TX-100) under different experimental conditions has been carried out using multiple physico-chemical techniques. The micellar parameters like critical micelle concentration (cmc), counter ion binding (β), thermodynamic parameters such as $\Delta G_m^0$, $\Delta H_m^0$, and $\Delta S_m^0$etc. associated with the drug-TTAB interaction have been determined. The changes of the values of cmc of TTAB by the addition of drug indicate the existence of TTAB-MFH interaction. The cmc values of drug-TTAB systems were found to be dependent on the variation of temperature, salt and alcohol concentrations. In all the cases the negative values of $\Delta G_m^0$indicated the spontaneous micelle formation of drug-TTAB system. The values of $\Delta H_m^0$and $\Delta S_m^0$reveal the existence of hydrophobic and electrostatic interactions between drug and TTAB. The CP values of TX-100 in water were increased in the presence of MFH. The values of $\Delta G_c^0$of drug-TX-100 mixed system are found to be positive which indicates the clouding process is nonspontaneous in nature. The binding constant (K_b) value for MFH-TX-100 system was found to be temperature dependent and the binding interaction between MFH and TX-100 is mainly due to hydrogen bonding.