Self-assembled micelles of N-phthaloylchitosan-g-poly (N-vinylcaprolactam) for temperature-triggered non-steroidal anti-inflammatory drug delivery

A thermo-sensitive biocompatible amphiphilic material, N-phthaloylchitosan-g-poly(N-vinylcaprolactam) which could self-assemble into spherical micelles with good stability in aqueous medium, was synthesized. Meloxicam (MLX), a strongly hydrophobic pain killer for ankylosing spondylitis, was encapsulated into the hydrophobic cores of the micelles successfully as a model drug. The micelles showed excellent stability after MLX loading. Furthermore, the prepared micelles presented obvious thermo-sensitivity with lower critical solution temperature around 32 A degrees C, where the MLX release rate reduced obviously when the temperature increased above it. This drug delivery system could achieve long time drug release under body temperature. The obtained biosurfactant should be an ideal candidate for applications in the development of long-lasting drug delivery systems.