Conductivity and cloud point studies of the interaction of lomefloxacin hydrochloride with anionic and nonionic surfactants in electrolytes solution

Abstract The interaction of lomefloxacin hydrochloride (LMFH) drug (utilized to treat different bacterial infections) with anionic (sodium dodecyl sulfate (SDS)) and nonionic (triton X-100 (TX-100)) surfactants in electrolytes media has been carried out applying the conductometric and cloud point (CP) measurement methods. SDS is very useful to prohibit different viral infections and to extract DNA/RNA. Two critical micelle concentrations (cmc) were observed for LMFH + SDS mixtures within the investigated surfactant concentration. The cmc values of SDS increase monotonically with the increase of the LMFH concentration. The cmc values of LMFH + SDS mixtures were reduced as the ionic strength of electrolytes increases. In the case of the LMFH + SDS mixture, the cmc values showed reverse U-shaped change with the augmentation of temperature in the electrolyte medium. The extent of counterion binding (β) varies significantly with the change of ionic strength of the electrolytes and concentration of the drug. The CP values of the LMFH + TX-100 mixture was increased and decreased with the enhancing of LMFH and electrolyte concentrations respectively. The standard Gibbs free energy changes both for first and second micellization ( Δ G 1 , m o & Δ G 2 , m o ) were attained to be negative throughout the study suggesting spontaneous micellization of LMFH + SDS mixture in all the cases. The Δ G 1 , m o & Δ G 2 , m o values increase with the increase of temperature. Again, Δ G 2 , m o  >  Δ G 1 , m o signify that second micellization is more spontaneous. The positive free energy changes of the LMFH + TX-100 mixture reveal the nonspontaneous nature of the clouding process. The non-spontaneity of clouding experiences a reduction with the rise of TX-100 concentration. The other thermodynamic parameters, transfer properties as well as entropy-enthalpy compensation parameters of micellization and clouding processes have been assessed. The intrinsic enthalpy ( Δ H m o , ∗ ) values reveal that micelle is more stable in electrolyte media.