Thermosensitive hydrogel based on poly(ether-ester anhydride) nanoparticle as drug delivery system: preparation, characterization and biocompatibility.

A novel temperature-response hydrogel was developed for drug-delivery applications. The hydrogel matrix (PES) was synthesized by melt polycondensation of poly(ether-ester) diacid based on PEG with low molecular weight and sebacic acid. The sol-gel-sol phase transitions of PES nanoparticle (NP) hydrogel were investigated. In vitro erosion of hydrogel was characterized by Fourier transform infrared spectroscopy, environmental scanning electron microscopy and dynamic light scattering. In vitro release behaviors of hydrophilic and hydrophobic drugs and in vivo histopathological evaluation were studied in detail. The study results revealed that an aqueous dispersion of PES nanoparticle freeze-dried powder exhibited reversible sol-gel transition behavior with increasing temperature. The hydrogel could maintain steadily at least a month during in vitro erosion process. There were sustained release behaviors of hydrophilic and hydrophobic drugs from PES NP hydrogel and histopathological studies confirmed that the PES NP hydrogel only provoked an acceptable modest inflammatory response. Thus, PES NP hydrogel is biodegradable, biocompatible and promising in controlling the incorporated drugs for sustained release.