Development of a polymeric nanoparticulate drug delivery system - In vitro characterization of nanoparticles based on sugar-containing conjugates

This paper reports the synthesis of polymeric nanoparticles from a sugar-containing conjugate for liver-specific drug delivery. The conjugate was composed of lactobionic acid. diamine-terminated poly(ethylene glycol) and cholic acid (abbreviated as LEC). The conjugate was characterized by H-1 NMR and FT-IR spectroscopy measurements. In aqueous media. the conjugate can self-assemble to form core-shell type nanoparticles. and the formation of a core-shell structure was observed by fluorescence spectroscopy. The critical association concentration (CAC) of the LEC conjugate nanoparticles was determined from fluorescence excitation spectra to be 0.05 g/l. The LEC nanoparticles were mostly spherical with sizes ranging from 10 to 30 nm. Clonazepam (CNZ) was used as a model hydrophobic drug. and was incorporated into the hydrophobic core of the nanoparticles. CNZ was released more slowly at a higher drug loading due to drug crystallization. (C) 2002 Elsevier Science B.V. All rights reserved.