Densities of L-Glutamic Acid HCl Drug in Aqueous NaCl and KCl Solutions at Different Temperatures

Abstract

Densities \((\rho )\) of (0.01 to 0.07) \(\hbox {mol}{\cdot } \hbox {kg}^{-1}\) L-Glutamic acid HCl (L-HCl) drug in water, and in aqueous NaCl and KCl (0.5 and 1.0) \(\hbox {mol}{\cdot } \hbox {kg}^{-1}\) solutions have been reported as a function of temperature at \(T = (298.15, 303.15, 308.15\), and 313.15) K and atmospheric pressure. The accurate density \((\rho )\) values are used to estimate the various parameters such as the apparent molar volume \((V_{2,{\upphi }})\), the partial molar volume \((V_{2}^{\infty })\), the isobaric thermal expansion coefficient \((\alpha _{2})\), the partial molar expansion \((E_{2}^{\infty })\), and Hepler’s constant \((\partial ^{2}V_{2}^{\infty }/\partial T^{2})_{P}\). The Cosphere overlap model is used to understand the solute–solvent interactions in a ternary mixture (L-HCl drug + NaCl or KCl + water). Hepler’s constant \((\partial ^{2}V_{2}^{\infty }/\partial T^{2})_\mathrm{P}\) is utilized to interpret the structure-making or -breaking ability of L-HCl drug in aqueous NaCl and KCl solutions, and the results are inferred that L-HCl drug acts as a structure maker, i.e., kosmotrope in aqueous NaCl solutions and performs as a structure breaker, i.e., chaotrope in aqueous KCl solutions.