Nanoaggregate of thermosensitive chitosan-Pluronic for sustained release of hydrophobic drug

A thermo-sensitive chitosan-Pluronic copolymer (CP) was prepared by grafting mono-carboxyl Pluronic onto the chitosan using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Indomethacin (IMC)-loaded nanoaggregate (NA) was prepared using the synthesized CP by the direct dissolution method. The critical aggregate concentration (CAC), hydrodynamic size and surface morphology of the prepared CP nanoaggregate (CPNA) were characterized by fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM), respectively. The resulting CAC and the average diameter of CPNA were about 0.31 g/l and 120 nm, indicating high structural stability of CPNA and size favorable for intravenous delivery of drugs. In vitro release test of the IMC encapsulated into CPNA showed sustained release rate of IMC as compared with that from Pluronic micelle. Therefore, we can conclude that our CPNA can be a novel type of superior drug carrier for sustained delivery of hydrophobic drugs.