Abstract

TEMPERATURE-DEPENDENT VOLUMETRIC AND VISCOMETRIC PROPERTIES OF L-PHENYLALANINE IN AQUEOUS METFORMIN HYDROCHLORIDE SOLUTIONS

Rajagopal K., Shailajha S., Mohamed Roshan M.* and Roy Richi Renold G.

Abstract

Densities and viscosities of L-Phenylalanine in (0.05, 0.10, 0.15 and0.20) mol kg-1 aqueous solutions of Metformin-HCl have beenmeasured at T = (298.15, 303.15, 308.15, 313.15 and 318.15) K andexperimental pressure p = 0.1 MPa to study nature of the interactionsof Phenylalanine with aqueous metformin hydrochloride (Metformin-HCl) as a function of temperature. Several thermodynamicalparameters such as partial molal volume Vφ, standard partial molalvolume Vφ0, transfer volume ΔVφ0, hydration number nH, the secondderivative of infinite dilution of partial molal volume with respect totemperature, viz., ∂2Vφ0 / ∂T2, viscosity B-coefficient, transfer BcoefficientΔB, variation of B with temperature (dB/dT), free energies of activation ofviscous flow Δμ10* and Δμ20* per mole of solvent and solute are reported. The dependence ofthese parameters upon concentration and temperature clearly show the presence of strongsolute - cosolute interactions. Furthermore the pair and triplet interaction coefficient havealso been calculated and reported.

Keywords: Standard partial molal volume, transfer volume, hydration number, viscosity B-coefficient, activation energy, L-Phenylalanine, Metformin hydrochloride.