Effect of 1-Butyl-3-methylimidazolium Ibuprofenate as an Active Pharmaceutical Ingredient Ionic Liquid (API-IL) on the Thermodynamic Properties of Glycine and l-Alanine in Aqueous Solutions at Different Temperatures

Abstract

Recently, ionic liquids have been combined with active pharmaceutical ingredients (APIs), and a third generation of ILs has emerged (API-ILs). The effect of a novel ionic liquid containing the ibuprofenate anion as an active pharmaceutical ingredient ionic liquid (API-IL) on the thermodynamic properties of two amino acids, glycine and l-alanine, have been studied. The densities, speeds of sound, viscosities and refractive indices of glycine and l-alanine in water and in aqueous solutions of an API-IL, 1-butyl-3-methylimidazolium ibuprofenate ([BMIM][Ibu]), have been determined at temperatures 288.15–318.15 K. The measured data have been used to calculate the standard partial molar volume $$ V_{\phi }^{0} $$ , partial molar volume of transfer $$ \Delta_{\text{tr}} V_{\phi }^{0} $$ , Hepler’s constant $$ (\partial^{2} V_{\phi }^{0} /\partial T^{2} )_{p} $$ , apparent molar isentropic compressibility $$ \kappa_{\phi } $$ , molar refraction R D, viscosity B coefficient (B) and hydration number parameters n H. All of these parameters are discussed in terms of the competitive interactions occurring between amino acids–[BMIM][Ibu] and amino acids–water.