#$%^&*AU2019101139A420200116.pdf#####ABSTRACT The present study will be carried out focusing on the preparation of pHresponsive nanoparticles for drug delivery based on polyethylene glycol (PEG) gel. In the process, the PEG-Schiff-DOX will be prepared by bonding doxorubicin to PEG polymer chain via acid-sensitive group (Schiff base bond). Consequently, it can be self assembled in aqueous solution to obtain nanoparticles for drug delivery and can be further loaded in the gelatin network to obtain PEG gel-based pH-responsive nanoparticles for drug delivery. Concerning its advantages, the composite material is characterized by high drug loading, high encapsulation efficiency and acid-controlled release, which can realize the construction of a multi-stage release system to achieve gradient or stimulated response release of doxorubicin. 1