Ultrasonic and Acoustic Investigation of Glutamic Acid and Aspartic Acid in Mixed Solvent Systems for Enhanced Drug Solubility and Bioavailability in Oral and Injectable Formulations

Abstract

The present study focuses on the ultrasonic and thermoacoustic investigation of glutamic acid and aspartic acid in various mixed solvent systems, including ethanol-water, DMSO-water, isopropanol-water, methanol-water, chloroform-water, and acetone-water. The research evaluates critical parameters such as density (ρ), ultrasonic velocity (U), viscosity (η), adiabatic compressibility (β), intermolecular free length (Lf), acoustic impedance (Z), free volume (Vf), internal pressure (πi), molar volume (Vm), Rao's constant (RC), and Wada's constant (WC). These parameters were analyzed over varying weight percentages (1%,3% and 5%) to understand solute-solvent and solvent-solvent interactions. The results demonstrate that the ultrasonic velocity and density generally increase with solute concentration, indicating stronger molecular interactions. The decrease in adiabatic compressibility and intermolecular free length reflects the formation of a tighter molecular network, reducing molecular free space. Variations in acoustic impedance and free volume further validate the interaction strength between amino acids and solvent molecules. Internal pressure analysis reveals insights into molecular cohesion, while molar volume, Rao’s, and Wada’s constants provide information on molecular packing and interaction dynamics. These findings contribute to a deeper understanding of the behavior of amino acids in mixed solvents, which is crucial for applications in biochemical, pharmaceutical, and industrial formulations.