Investigation of molecular interactions insight into some biologically active amino acids and aqueous solutions of an anti-malarial drug by physicochemical and theoretical approach

Abstract

Herein we have made a comprehensive analysis of the mode of interactions between the L-Alanine/L-Valine and Chloroquine diphosphate in aqueous solution. Evaluation of different Physico-chemical parameters like density, viscosity, refractive index, conductance study (at three different temperatures), and surface tension (at 298.15 K) at atmospheric pressure have used to help in the gathering of knowledge about the existence of plausible intermolecular interactions in the ternary (Drug + Water + Amino acid) solution. Furthermore, apparent molar volume, limiting apparent molar volume, viscosity B-coefficient, and molar refraction, limiting molar refraction all support the idea that the leading solute–solvent interaction is influenced by the solute concentration and temperature. In addition, in aqueous Chloroquine diphosphate, both amino acids showed structure-breaking activities. The system's Gibbs free energy change was measured, suggesting its spontaneity. The 1H NMR spectroscopy results showed significance changes in the shifting of aromatic protons of CDP and protons of amino acids indicating that a strong interaction (hydrophobic-hydrophobic) takes place among them which is further supported by our theoretical observations. L-Valine-Drug interactions were found to be more predominating over L-Alanine-Drug interactions, according to both experiment and theory. Models for mixtures of drug molecules and amino acids could be developed using the experimental and correlated results.