Solubilisation of griseofulvin in aqueous micellar solutions of diblock copolymers of ethylene oxide and 1,2-butylene oxide with lengthy B-blocks

Abstract The influence of hydrophobic-block length on solubilisation capacity was examined for micelles of E m B n copolymers (E = oxyethylene, B = oxybutylene, subscripts denote number-average block lengths in repeat units) with B-block lengths in the range of 30–76 and with E-blocks of sufficient length to ensure the formation of spherical micelles. Griseofulvin was used as a model poorly-water-soluble drug known to be almost exclusively solubilised in the micellar core. Combination of solubilisation data with those of a previous study has shown that the amount of drug solubilised per gram of hydrophobe is essentially independent of B-block length when this exceeds about 15 B units, suggesting that core size is not a major influence on solubilisation.