Binding interactions of anesthetic drug with surface active ionic liquid

The application of aggregation behavior of a surface active ionic liquids (SAILs), 1-dodecyl-3-methylimidazolium chloride [C12mim][Cl] and 1-tetradecyl-3-methylimidazolium chloride [C14mim][Cl] in drug delivery of lidocaine hydrochloride has been investigated from surface tension and fluorescence measurements at 298.15 K and from conductance at 288.15, 298.15 and 308.15 K. Critical aggregation concentration (CAC), degree of ionization (α), and various thermodynamic parameters like Gibbs free energy of aggregation (∆ Gagg.°) standard enthalpy of aggregation (∆ Hagg.°) and standard entropy of aggregation (∆ Sagg.°) are calculated using conductivity measurements. The surface activity of the ILs in various mixed solvents are examined from surface tension measurements by calculating various surface parameters like maximum surface excess concentration (Гmax), minimum surface area per ionic liquid molecule (Amin), adsorption efficiency (pC20), effectiveness of surface tension reduction (Πcac) surface tension at CAC (γcac), p (packing parameter), and CAC at different compositions. Fluorescence measurements have been employed to get detailed insight of the local microenvironment of the aggregates, and critical aggregation concentration (CAC). Decrease in the CAC values was observed with the increase in the amount of drug which is attributed to the balancing between electrostatic and hydrophobic interactions. This shows that the spontaneity of aggregation process of IL increases with the increase in the concentration of drug.