Study of local anesthetics. Part* 166:Conductometric determination of the critical micelle concentration of local anesthetic heptacainium chloride in aqueous electrolvte solution

Specific conductivities of local anesthetic heptacainium chloride XlX (HCC XlX) (N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-piperidinium chloride), in aqueous electrolyte solution (0.05 mol.1⁻¹ NaCl) were measured as a function of the concentration and temperature. The critical micelle concentrations (c.m.c) and the counterion (β) binding of the micelles were estimated from the dependence of the specific conductivity of the substrate concentration. The temperature dependence of ln c.m.c was fitted to the function of the second degree polynomial. From the fitting parameters, Gibss free energies (ΔG⁰), enthalpies (ΔH⁰), and entropies (ΔS⁰) of micellization as a function of temperature were estimated. The "mass action model" was applied to micelle formation to calculate the micellization parameters.