Effect of Nanoparticle Additives on Partitioning of Cephalexin in Aqueous Two-Phase Systems Containing Poly(ethylene glycol) and Organic Salts

Abstract

In this work, the ability of four nanoparticles including Al2O3, TiO2, graphene, and graphene oxide (GO) as additives for extraction of cephalexin in aqueous two-phase systems composed of polyethylene glycol (PEG) and three sodium-based organic salts was investigated. For this purpose, phase diagrams and the liquid–liquid equilibrium (LLE) data for the {PEG 6000 + sodium citrate, sodium tartrate, sodium succinate + H2O} and partition coefficient for cephalexin were determined. The addition of 0.001 wt % graphene oxide increased the partition coefficient by 9% for the {PEG + sodium citrate + water} system, while other nanoparticles had no effect or decreased the partition coefficient. To investigate the effect of GO concentration on the partition coefficient, various concentrations ranging from 0.005 to 0.04 wt % was examined. It is observed that at a GO concentration equal to 0.01 wt %, the maximum partition coefficient improvement is achievable to be 59%. The highest partition coefficient 5.74 was obtained for the system {PEG6000 19 wt %, sodium citrate 10 wt %, and GO 0.01 wt %}. It can be concluded that a trace amount of nanoparticles can change the partition coefficient either by increasing or decreasing. It seems that the concentration of nanoparticle also has a significant effect on the partition coefficient.