Facile synthesis of amphiphilic chitosan-g-poly(lactic acid) derivatives and the study of their controlled drug release



We report here a simple and green procedure for the synthesis of amphiphilic chitosan (CS) derivatives with poly(lactic acid) (PLA) side chains, without the use of high pure lactide, high temperatures, or large amounts of organic solvent. The chemical structure and physical properties of these CS derivatives were characterized by Fourier transform infrared spectroscopy, 1H-NMR, thermogravimetric analysis, and X-ray diffraction. The formation and characteristics of polymeric micelles based on these CS derivatives were studied by fluorescence spectroscopy and dynamic light scattering. The critical aggregation concentration in water varied from 0.048 to 0.021 mg/mL, and the mean diameter was in the range 169.8–260.7 nm in aqueous solution at 25°C when the PLA grafting percentage increased from 92 to 132%. Transmission electron microscopy showed that the micelles exhibited a nanospheric morphology within a size range of 60–120 nm. For the resulting micellar aggregates, the drug loading and in vitro drug-release characteristics were studied with indomethacin as the model drug. We found that such micellar aggregates could be potentially used as nanocarriers for drug delivery. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 908-915, 2013