Investigations on molecular interactions of memantine hydrochloride in aqueous solutions by thermophysical methods and molecular dynamics simulations at different temperatures

The density (rho), speed of sound (u), and refractive index (nD) of aqueous solutions of Memantine hydrochloride with molalities ranging from 0.0 to 0.05 at atmospheric pressure and temperatures between 305.15 and 320.15 K were investigated. The experimental results have been used to compute apparent molar volume (V phi), limiting values of apparent molar volume (V phi 0), the limiting apparent molar expansibility (E0 phi), Hepler's constant ( partial differential 2V0 apparent molar adiabatic compressibility (k phi), limiting values of apparent adiabatic compressibility (k0 phi), specific refraction (RD), molar refraction (RM) and hydration number (nh). These data indicated the existence of substantial solute-solvent interactions in the liquid system, as well as hydrogen bond, dipole-dipole, dipole-induceddipole interactions and solute structure-making capacity. Good correlations with the experimental studies were observed from molecular dynamics (MD) simulation studies.