(378k) Volumetric and Acoustic Properties of Metamizole and Polyethylene Glycol (PEG 200) in Water at Different Temperatures

In order to verify possible effects of the interactions of painkiller with polyethylene glycols, experimental data for density and speed of sound of metamizole (dipyrone) in polyethylene glycol solutions (PEG200) were determined at different temperatures and concentrations and at atmospheric pressure (p = 92,3 kPa). Densities and sound velocities of the solutions were obtained using a Density and Sound Velocity Analyzer, manufactured by Anton Paar (Model DAS 5000). The solutions were prepared at concentrations of m ~ (0.1 - 0.7) mol·kg^-1 in pure water and in solutions of polyethylene glycols with a concentration of m = (0.025; 0.050; 0.075 and 0.100) mol·kg^-1. Data were determined at temperatures T = (283.15; 288.15; 293.15; 298.15 and 303.15) K. From the experimental results of density and speed of sound, the following thermodynamic properties were calculated: the apparent molar volume, the partial molar volume at infinite dilution, the partial molar volume of transfer of dipyrone from water to the PEG solutions, the apparent molar isentropic compressibility, the partial molar isentropic compressibility at infinite dilution and the partial molar transfer isentropic compressibility of dipyrone from water to the PEG solutions. The behavior of the volumetric and acoustic properties at infinite dilution leads to the assumption of weak solute-solute interactions and strong solute-solvent interactions.