Context: Polymeric nanoparticles (NPs) have been used frequently as drug delivery vehicles. Surface modification of polymeric NPs with specific ligands defines a new biological identity, which assists in targeting of the nanocarriers to specific cancers cells. Objective: The aim of this study is to develop a kind of modified vector which could target the cancer cells through receptor-mediated pathways to increase the uptake of doxorubicin (DOX). Methods: Folate (FA)-conjugated PEG-PE (FA-PEG-PE) ligands were used to modify the polymeric NPs. The modification rate was optimized and the physical-chemical characteristics, in vitro release, and cytotoxicity of the vehicle were evaluated. The in vivo therapeutic effect of the vectors was evaluated in human nasopharyngeal carcinoma KB cells baring mice by giving each mouse 100 ml of 10 mg/kg different solutions. Results: FA-PEG-PE-modified NPs/DOX (FA-NPs/DOX) have a particle size of 229 nm, and 86% of drug loading quantity. FA-NPs/DOX displayed remarkably higher cytotoxicity (812 mm 3 tumor volume after 13 d of injection) than non-modified NPs/DOX (1290 mm 3 ) and free DOX solution (1832 mm 3 ) in vivo. Conclusion: The results demonstrate that the modified drug delivery system (DDS) could function comprehensively to improve the efficacy of cancer therapy. Consequently, the system was shown to be a promising carrier for delivery of DOX, leading to the efficiency of antitumor therapy.

Purpose. Biodegradable polymeric nanoparticles have been used frequently as gene delivery vehicles. The aim of this study is to modify bioadhesive PLGA nanoparticles with novel synthetic mannan-PEG-PE (MN-PEG-PE) to obtain active targeted gene delivery system.Methods. Mannan-PEG-PE ligands were synthesized and modified onto the NPs/pEGFP complexes. The modification rate was optimized, and the characteristics of the vehicle were evaluated. Then, the modified vectors were intravenous delivered to rats, andin vivotargeting behavior of MN-PEG-PE modified PLGA nanoparticles/pEGFP complexes (MN-PEG-PE-NPs/pEGFP) in liver macrophages was investigated.Results. MN-PEG-PE-NPs/pEGFP displayed remarkably higher transfection efficiencies than nonmodified NPs/pEGFP bothin vitroandin vivo.Conclusions. Mannan containing targeting ligands could significantly improve the transfection efficiency of the carriers. MN-PEG-PE modified vectors very useful in targeted gene delivery.