The influence of selected polyoxyethylene glycols on the electrical conductivity of isosmotic and hyperosmotic natrium chloride solutions.

Background: Polyethylene glycols (PEGs) are widely applied in technology of pharmaceutical products, as well as in other branches of industry. Owing to their physicochemical properties, they are particularly effective in enhancing the solubility of a wide range of drug formulations.

Objectives: The aim of the study was to evaluate the effect of PEGs on the physicochemical parameters of model systems containing different concentrations of sodium chloride (NaCl), with particular emphasis on the specific conductivity of these solutions.

Material and methods: A series of aqueous solutions containing 0.9% and 9.0% NaCl, with increasing mass concentrations (2.0-25.0% w/w) of PEG 200 and PEG 4000, were prepared and analyzed. Their specific conductivity was tested using a CC-505 conductivity meter with an EC-70 conductivity sensor; also, densities and viscosities of the tested solutions were evaluated.

Results: The increased concentration of polymers in the system resulted in decrease of the specific conductivity and molar conductivity in each of the series of evaluated solutions. An inverse relationship occurred in viscosity measurements, which increased with increasing PEG content in the system.

Conclusions: The addition of PEG 200 and PEG 4000 to aqueous NaCl solutions affected both the specific conductivity and viscosity of these systems. Both types of polymers had similar effects on conductivity changes in 0.9% and 9.0% NaCl solutions.