The structural effect on volumetric and acoustic properties of aqueous anti-HIV drugs (Emtricitabine and Lamivudine) at various temperatures☆

Abstract In this work, density ( ρ ) and speed of sound ( u ) data were measured for aqueous solutions of two drugs namely Emtricitabine and Lamivudine in the various concentrations, m from (293.15 to 318.15) K and at 0.1 MPa pressure. The measured density and speed of sound data were used to calculate the apparent molar volume ( V ϕ ) and the isentropic compressibility ( κ s ), using Laplace–Newton's equation. The apparent molar volume at infinite dilutions ( V ϕ ∞ ) of drugs has been evaluated from linear equation. The temperature dependence of apparent molar volume at infinite dilution ( V ϕ ∞ ) can be expressed as the second-order polynomial equation, in turn apparent molar expansibility ( E ϕ ∞ ) at infinite dilution was calculated. These parameters have been used to understand the effect of temperature on interactions between drugs and water. Moreover, the structure making and breaking ability of drugs are analyzed at experimental conditions.