Investigation of molecular interactions of a drug Isoprenaline Hydrochloride-L-alanine in water at different temperatures

Abstract

Studies of volumetric and compressibility properties of aqueous solutions of medicinal compounds are essential for understanding the molecular interactions between the drug and solvent molecules. In this regard, we have measured the density and speed of sound data for the drug i.e. isoprenaline hydrochloride in aqueous medium and in 0.05 mol.kg−1 aqueous L-alanine solution within the molality range (0.05–0.12 mol.kg−1) at different temperatures i.e. T = 293.15, 298.15, 303.15, 308.15 and 313.15 K. This data have been used to obtain the apparent molar volume of soluteVϕ, isentropic compressibilityκs of solutions and apparent molar isentropic compressibility of solute KS,ϕ as a function of concentration of the drug. The temperature variation data enabled us to calculate apparent molar expansivityEϕ and limiting expansivity at infinitely dilute solutionsEϕ0 at selected temperatures. The results are discussed in terms of ion–solvent interactions in binary solutions and the effect of addition of amino acid on the similar interactions.