Structure-making behaviour of L-arginine in aqueous solution of drug ketorolac tromethamine: volumetric, compressibility and viscometric studies

ABSTRACTIn this work, density ρ, speed of sound u and viscosity η, were measured for L-arginine in aqueous ketorolac tromethamine solutions at various temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and at atmospheric pressure. Apparent molar volume VΦ, limiting apparent molar volume V°Φ, limiting apparent molar volume of transfer V°Φ,tr, limiting molar expansivity E°Φ, Hepler’s constant and hydration number nH were obtained using density data. Apparent molar isentropic compression KΦ,S, limiting apparent molar isentropic compression K°Φ,S, limiting apparent molar isentropic compression of transfer K°Φ,S,tr and hydration number nH were obtained using speed of sound data. Jones–Dole coefficient-B B, viscosity B-coefficients of transfer Btr, variation of B with temperature (), free energy of activation of viscous flow per mole of solvent Δμ°#2 and per mole of solute Δμ°#1 were obtained from viscosity data. The obtained results are discussed in terms of solute–solvent interactions in these systems.