Funct. Mater. 2023; 30 (1): 60-64.


Study of viscosity and quasi-thermodynamic activation parameters for viscous flow in the system water-(propylene glycol-macrogol 400)

O.P.Bezugla1, A.P.Krasnopyorova2, A.M.Liapunova1, G.D.Yukhno2, M.O.Lyapunov1

1State Scientific Institution "Institute for Single Crystals", National Academy of Sciences of Ukraine, 60 Nauki ave., 61072 Kharkiv, Ukraine
2Research Institute of Chemistry of V.N.Karazin Kharkiv National University, 4 Svobody Sq., 61022 Kharkiv, Ukraine


The results of a polythermal study of the dynamic viscosity (η) of the ternary system containing water and the mixture of propylene glycol (PG) and macrogol 400 (M400) are presented. The values of η for the ternary system vary widely depending on its composition and temperature. The isotherms of η are nonlinear. The isotherms of excess dynamic viscosity (ηE) are asymmetric, which indicates a different structure of the ternary system depending on the water content. The absolute values of the ηE on the relevant isotherms decrease with increasing temperature. The quasi-thermodynamic activation parameters of viscous flow are positive regardless of the ternary system composition. Changes in their values indicate the destruction of water structure under the influence of PG and M400. The dependencies of the excess quasi-thermodynamic activation parameters of viscous flow on the mole fraction of non-aqueous solvent (PG - M400) make it possible to differentiate the areas of compositions with different structures: structure of water, structure of mixed solvents with the dominance of water structure or non-aqueous solvent, and structure of non-aqueous solvent. The structure of the ternary mixed system can affect the properties of heterogeneous disperse systems with a liquid dispersion medium.

water, propylene glycol, macrogol 400, viscosity, activation parameters of viscous flow.
1. Handbook of Pharmaceutical Excipients, ed. by P.J.Sheskey, B.C.Hancock, G.P Moss, D.J.Goldfarb, Ninth edition, Pharm. Press, London (2020).
2. Yu.Ya.Fialkov, A.N.Zhitomirskii, Yu.A.Tarasenko, Physical Chemistry of Non-Aqueous Solutions, Chemistry, Leningrad (1973) [in Russian].
3. O.Yu.Sytnik, A.P.Krasnoperova, V.A.Lebedinets, K.M.Sytnik, Journal of Applied Chemistry, 78, 725 (2005) [in Russian]..
4. A.P.Krasnoperova, Bulletin of Kharkov University. Chemical Sciences, 2, 178 (1998) [in Russian]..
5. O.N.Dyment, K.S.Kazanskii, A.M.Miroshnikov, Glycols and other Derivatives of Ethylene and Propylene Oxides, Khimiya, Moscow (1976) [in Russian].
6. The European Pharmacopoeia, 11th Edition (2022). EDQM. Strasbourg: Council of Europe. Available at:
7. L.J.dos Santos, L.A.Espinoza-Velasquez, J.A.P Coutinho et al., Fluid Phase Equilibria, 522, 112774 (2020). 10.1016/j.fluid.2020.112774
8. P.Amalendu, Y.P.Singh, J. Chem. Eng. Data, 41, 1008 (1996).
9. Molecular Interactions, ed. by G.Ratajczak, W.Orville-Thomas, Mir, Moscow (1984) [in Russian].
10. N.Lyapunov, O.Bezugla, A.Liapunova et al., ScienceRise: Pharmaceutical Science, 39, 29 (2022).


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