Thermophysical properties of lidocaine:thymol or l-menthol eutectic mixtures

Abstract

Backgrounds

A key objective of green chemistry is to obtain a broad database of thermophysical properties of liquid mixtures. Thus, the replacement of conventional solvents with ecological ones will be facilitated.

Methods

Herein, two eutectic systems with therapeutic properties are characterized. They are binary mixtures of lidocaine and thymol or l-menthol. Properties as solid-liquid equilibrium, density, speed of sound, refractive index, isobaric molar heat capacity, surface tension, and viscosity were determined at 0.1 MPa and several temperatures. From them, others derivatives were calculated. In addition, the phase diagram was correlated with NRTL model and the density and isobaric molar heat capacity were modelled with PC-SAFT equation of state.

Significant findings

Although the mixtures with l-menthol were almost ideal, a complex diagram owing the presence of stable and metastable phases. For these mixtures, the values of all measured properties were lower than those with thymol. Results indicated that PC-SAFT can be used to predict the thermodynamic behaviour of both systems in any working condition.