Objective To determine the physicochemical properties of iRGD conjugated doxorubicin loaded liposome (iRGD-LP-DOX), and its effect on targeting and inhibiting growth of A549 cells. Methods Liposomes were observed under a transmission electron microscope. Release of doxorubicin from iRGD-LP-DOX was detected by the dialysis bag method. The efficiency of cellular uptake and tumor spheroids penetration on A549 cells in vitro was determined. The anti-proliferation efficiency of iRGD-LP-DOX was evaluated by MTT assay using IC 50 (50% inhibition concentration). Results iRGD-LP-DOX was spherical in a uniform size. Free DOX was released by 100% in 5 h, while LP-DOX and iRGD-LP-DOX were released by about 40% in 48 h. A higher level of iRGD-LP-DOX uptaken by A549 was found compared with that of LP-DOX （ P P
