Physicochemical parameters and thermodynamic behavior of aprepitant/HS15 micellar system at different temperatures: Effect of electrolytes concentration

Aprepitant(APPT) is a drug used for suppressing nausea and vomiting. Here, an in-depth study was conducted on how the concentration of sodium salt electrolyte (NaCl or Na2SO4) and temperature (293.15-313.15 K with an interval of 5.0 K) affect the thermodynamics of APPT/HS15 micelle system in terms of the interface and micellization behavior. The critical micelle concentration (CMC) was evaluated fromsurface tension measurement. The results show that anions from the two electrolytes disrupted hydration of the surfactant and changed the CMC, dynamic light scattering, and the air-water interface parameters, thereby facilitating the formation of micelles. According to the measured standard Gibbs free energies for micellization and adsorption (Delta G(m) and Delta G(ads), respectively), micellization between APPT and HS15 was spontaneous. The temperature and electrolyte have a synergistic effect on the spontaneous micellization. We also calculated related physical and chemical parameters such as the maximum surface excess concentration (Gamma(max)), themolecular adsorption limit area (A(min)), the effect on surface tension reduction (Pi(cmc)), and the equilibrium surface free energy (Delta G(min)). In the APPT/HS15 system, electrolytes lower the energy requirement for forming micelles and makes the formed micelles more stable. Above all, NaCl and Na2SO4 can stabilize the APPT/HS15 system, which provides a reference for the clinical application of APPT. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the thermodynamics of the APPT/HS15 micelle system under various concentrations of sodium salt electrolytes and temperatures, revealing that electrolytes lower the energy requirement for micelle formation and increase stability. Synergy between temperature and electrolytes was found to facilitate spontaneous micellization.