Stability and release performance of a series of pegylated copolymeric micelles

Purpose. The aim of this work is to evaluate the capability of a series of biocompatible amphiphilic copolymers as a nano- sized drug carrier. Methods. The influences of the type of lactone monomer, the feed molar ratios of lactone/ PEG, and the molecular weight of PEG on the performance and release behavior of micelles are investigated. Results. These pegylated amphiphilic copolymers efficiently form micelles with a low CMC value in the range of 10(-6) - 10(-7) M. The average particle size of micelles is similar to 100 nm. The phenomenon of increasing particle size as increasing the chain length of poly( lactone) block is observed. The different hydrophobicity, based on chemical structure of poly( lactone), accounts for different interaction strength between indomethacin and hydrophobic inner core, which further influences the drug loading in copolymeric micelles and their release character. In addition, the PCL/ PEG/ PCL micellar solutions maintain their sizes at 4degreesC for 8 weeks without occurring significant aggregation or dissociation. Conclusions. A series of biocompatible pegylated amphiphilic copolymers have been elucidated possessing micellization potential to form nano- sized micelles in an aqueous environment, which enable incorporate hydrophobic drug and regulate drug release.