Aqueous two-phase systems based on thermo-separating copolymer for partitioning of doxorubicin

Abstract

Copolymers have high potential for using in aqueous two-phase systems (ATPSs) due to their tunable physico-chemical properties. In this work, the phase behavior and the application of dextran – (PEG-PPG) random copolymer (UCON) ATPS for partitioning of doxorubicin were studied. Merchuk, Guan and the modified Guan relations were used to correlate the binodal experimental data. The effect of pH, molecular weight of dextran, weight fractions of UCON and NaCl as an additive on the partitioning of doxorubicin was investigated. Increasing the dextran molecular weight increased the partition coefficient, while pH had no significant effect on it. An enhancement of the weight fraction of UCON in the feed increases the partition coefficient of doxorubicin. NaCl in these ATPSs causes an increase in partition coefficient; however, NaCl concentration has no significant effect on partitioning of doxorubicin. This shows that electrostatic interaction is not the overcoming factor in the partitioning of doxorubicin. Besides, the interactions among the components in the studied aqueous two-phase systems were studied applying the Flory-Huggins parameter. It should be mentioned that the Flory-Huggins parameter was determined by the Hansen solubility parameter.