Abstract <p>Hydration properties of venlafaxine hydrochloride are significant in view of pharmaceutical applications. The effect of trisodium citrate salt on thermophysical properties of venlafaxine drug in aqueous solutions has been evaluated. Densities, ultrasonic velocities and refractive indices for system containing venlafaxine hydrochloride (VFH) + trisodium citrate salt (TSC) + water have been measured at 303.15 K and atmospheric pressure. The measured data have been used to calculate standard partial molar volume, compressibility and their corresponding transfer properties namely transfer volume and compressibility. The results have been interpreted in terms of different types of interactions and hydration behavior of the drug. Release of water molecules from hydration shells of the drug due to dehydration effect of trisodium citrate salt has been observed.</p>