Doxorubicin encapsulation and diffusional release from stable, polymeric, hydrogel nanoparticles

We have recently described the preparation of stable, polymeric nanoparticles, composed of poly(ethylene glycol) and poloxamer 407 (Pluronic® F127), prepared via inverse emulsion photopolymerization. In the present study we report on the performance of this novel colloidal system as a controlled delivery system for small hydrophobic drugs. Successful encapsulation of doxorubicin occurred through hydrophobic interactions, taking advantage of particle nanoarchitecture. Loadings of up to 8.7 wt.% were achieved with a reproducible, fast, solvent evaporation procedure. In vitro drug release, monitored by fluorescence spectrometry and HPLC, revealed a minor burst (approximately 10% at 37 °C) and sustained, diffusional release for over 1 week; furthermore, drug encapsulation significantly delayed doxorubicin degradation kinetics.