Effects of inorganic salts on solubilization of estriol in an aqueous solution of poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer.

The effects of inorganic salts on the solubilization of estriol was studied in an aqueous solution of a poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer (Pluronic L-64). The solubility of estriol increased with increasing Pluronic L-64 and salt concentrations. Furthermore, two clear transition points corresponding to the polymolecular micelle formation and a pronounced change in micellar structure of Pluronic L-64 were found on the solubility curves. The effectiveness of inorganic salts for increasing solubility of estriol followed approximately the lyotropic or Hofmeister series, except Li+.