The ultrasonic velocity, U, density, and viscosity of aqueous and non-aqueous (water + dioxan) solutions of tetracycline hydrochloride and chlorotetracycline have been measured at two different temperatures. Partial molal volumes, [Formula: see text] partial molal compressibility, [Formula: see text], Vand's interaction coefficients, Q and C, and thermodynamic activation parameters ΔG*, ΔS*, and ΔH* of these solutions have been computed from the ultrasonic velocity, density, and viscosity data. The results are interpreted in terms of solute–solvent interaction.
