Evaluation of polymeric nanoparticles composed of cholic acid and methoxy poly(ethylene glycol)

Amphiphilic polymeric conjugate based on cholic acid (CA) as the hydrophobic component and methoxy poly(ethylene glycol) (MPEG) as the hydrophilic component was synthesized using a 1,1'-carbonyldiimidazole (CDI) mediated conjugation. Fluorescence spectroscopy measurements suggested that CA and MPEG (abbreviated as CE) conjugate was associated in water to form polymeric core-shell type nanoparticles with a critical association concentration (CAC) value of 0.063 g l(-1). From the transmission electron microscope (TEM) observation, CE nanoparticles were almost spherical with a size range of approximately 10-30 nm in the dried state, which was in agreement with the result from particle size measurement using photon correlation spectroscopy (PCS). Clonazepam (CNZ) was physically loaded into the CE nanoparticles with a 16.2 wt.% loading. CNZ release was pseudo zero-order in kinetic terms for up to 3 days.