Measurement and correlation of the solubility of Lidocaine in eight pure and mixed solvents at temperatures from (292.15 to 332.15) K

The aim of this work is to obtain solubility data of lidocaine, and correlate equation parameters of lidocaine and thermodynamic parameters in the dissolution process. The solubility of lidocaine was experimentally measured in eight pure solvents including ethanol, n-propanol, isopropanol, n-butanol, isobutanol, acetone, methyl acetate, ethyl acetate, and binary mixtures (n-propanol + ethanol) at (292.15 to 332.15) K in atmospheric pressure by gravimetric method. The solubility of lidocaine in the solvents increased with a rise of temperature. The acquired solubility data of lidocaine in the solvents studied were correlated by using the modified Apelblat equation, van't Hoff equation, λh equation, Wilson model and NRTL model. The correlated values based on all the selected equations showed good agreement with the experimental values. Besides, the dissolution enthalpy ∆ H°sol, the dissolution entropy ∆ S°sol and the molar Gibbs free energy ∆ G°sol were calculated. Consequently, the obtained solubility and thermodynamic studies would be very helpful for optimizing the purification process of lidocaine.