Investigation of molecular interactions of the drug Diclofenac sodium salt in water and aqueous sorbitol systems at different temperatures (305.15 K–315.15 K)

The interactions of Diclofenac Sodium Salt (DSS) with water and aqueous sorbitol as a function of temperature have been investigated by volumetric, acoustic and conductance studies. Densities, speed of sound and conductance of DSS in water and aqueous solutions of sorbitol (0.002, 0.004, 0.006) mol·kg−1 have been measured at temperature (T) = (305.15 K, 310.15 K and 315.15 K) and atmospheric pressure. Density data was used to calculate apparent molar volume (Φv), limiting apparent molar volume (Φvo), slope (Sv) and partial molar volumes of transfer (ΔtrΦvo). The ultrasonic speed was used to calculate adiabatic compressibility (β), intermolecular free length (Lf), specific acoustic impedance (Z). The Walden's product was calculated from the conductance and viscosity data. The positive values of (∂2Φv0/∂T2)P and positive values of Λm0η0 with temperature suggest that DSS acts as structure maker in water and aqueous sorbitol systems.