OBJECTIVE Triptolide-loaded solid lipid nanoparticles(SLN)coated with polyethylene glycol(PEG)derivatives were prepared,and its physicochemical properties were investigated.METHODS The optimized TPL-SLN was prepared for further evaluation.The solid lipid nanoparticles(SLN)of TPL were prepared by melt emulsification.Single factor,five-level central composite design(CCD)was applied to explore the optimum levels of independent variables such as particle size,encapsulation efficiency(EE)and drug loading(DL).Phy...