Molecular dynamics and related solution chemistry of lovastatin in aqueous solution of arginine: Viscometric analysis

The solubility of lovastatin (LVS; solute) in water (solvent) is enhanced in the presence of arginine (ARG) as the cosolute. Therefore, this current study was conducted to delve further into the solute-cosolute and solute-solvent interactions and their thermodynamics. The viscosity of ARG and LVS-ARG solution systems was determined at various concentrations of aqueous ARG (0.01, 0.03, 0.09, 0.27, 0.5, 0.7 & 0.8 mol·dm−3) with saturated presence of LVS (LVS-ARG) at four different experimental temperatures (298.15, 303.15, 308.15 and 313.15 K). Viscosity data obtained were used to derive viscosity parameters such as Falken-Hagen coefficient (AF), Jones-Dole coefficient (BJ), rate of change of Jones-Dole coefficient (dBJ/dt), contribution per mole of the solute to free energy of activation for viscous solution (Δμ2°), corresponding value for pure solvent (Δμ1°) and the Walden product (η0Λ0). The data were then treated using various equations proposed by Einstein, Vand and Moulik. At the end of the study, the results from the viscometric study have been adequately explained by aforementioned equations with their respective parameters. The result indicates significant solute-solute and solute-solvent interactions.