Three triblock copolymers of ethylene oxide and phenyl glycidyl ether, type E(m)G(n)E(m), where G = OCH2CH(CH2OC6H5) and E = OCH2CH2, were synthesized and characterized by gel-permeation chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and NMR spectroscopy. Their association properties in aqueous solution were investigated by surface tensiometry and light scattering, yielding values of the critical micelle concentration (cmc), the hydrodynamic radius, and the association number. Gel boundaries in concentrated micellar solution were investigated by tube inversion, and for one copolymer, the temperature and frequency dependence of the dynamic moduli served to confirm and extend the phase diagram and to highlight gel properties. Small-angle X-ray scattering was used to investigate gel structure. The overall aim of the work was to define a block copolymer micellar system with better solubilization capacity for poorly soluble aromatic drugs than had been achieved so far by use of block copoly(oxyalkylene)s. Judged by the solubilization of griseofulvin in aqueous solutions of the E(m)G(n)E(m) copolymers, this aim was achieved.

The aim of this study was to define a block copolymer micellar system with a high solubilization capacity for poorly soluble aromatic drugs. Ethylene oxide and phenyl glycidyl ether were sequentially polymerized to form the diblock copolymer G5E67 (G = phenyl glycidyl ether, OCH2CH(CH2OC6H5); E = oxyethylene, OCH2CH2; subscripts denote number-average block lengths in repeat units). The association properties in aqueous solution over the range 20-50 degrees C were investigated by surface tensiometry and light scattering, yielding values of the cmc, hydrodynamic radius, and association number; gel boundaries in concentrated micellar solution were investigated by tube inversion. The solubilization capacity of G5E67 for the poorly water-soluble drug griseofulvin was higher than that of a triblock EGE copolymer of longer G block length and considerably higher than that achieved with poloxamers (EmPnEm, P = oxypropylene).