Studies on molecular interactions of l-histidine/l-serine in aqueous diphenhydramine hydrochloride solutions at various temperatures: Volumetric, ultrasonic and viscometric approach

Abstract

Thermophysical properties for varying concentrations of essential (L-histidine) and non-essential (L-serine) amino acids in water and (0.05–0.15) mol kg−1 mixed aqueous diphenhydramine hydrochloride solvent system has been deliberated at different temperatures ranging (293.15−318.15) K and ambient pressure (101.3 kPa). The experimentally obtained data has been utilized to compute different volumetric, compressibility and rheological parameters such as apparent molar volume (Vϕ), partial molar volume (V0ф), partial molar expansibility (E0ϕ), apparent molar isentropic compression (Kϕ,s), partial molar isentropic compression (K0ϕ,s), hydration number (nH), transfer parameters, viscosity coefficients etc. The structure breaking ability of the solute molecules has been comprehended using Hepler′s constant (temperature derivative of partial molar expansibility at constant pressure) and dB/dT (temperature derivative of viscosity B-coefficient) values. Further, by using the co-sphere overlap model various sorts of solute-drug interactions prevailing in the systems have been discussed.