To evaluate the antitumor activity and pharmacokinetics of podophyllotoxin(PPT) incorporated into solid lipid nanoparticles(SLN),Kunming mice inoculated with flesh tumor were used as animal model.The mice received a single daily intraperitoneal injection of PPT in 20% ethanol(5 mg/kg) and PPT-SLN(5 mg/kg in PPT) for 3 weeks.Gross tumor volumes,body weight and clinical observations were recorded daily.The mice were sacrificed for 24 h after the last administration,and the tumor inhibition rate was calculated with the tumor weight.For the pharmacokinetics research,the mice were treated with intraperitoneal injection of PPT(10 mg/kg) and PPT-SLN(10 mg/kg in PPT).Blood samples were collected at different time to determine the PPT concentration in plasma by HPLC.Blood drug level-time curve was made and pharmacokinetic parameters were calculated.As a result of drug administration,the tumor volume and weight of the mice injected with PPT-SLN were significantly restrained compared with mice treated with PPT or negative control.The tumor inhibition rate of 58.13% showed a significant antitumor activity of PPT-SLN.At the same time,the increased weight gain of the mice injected with PPT-SLN suggested a reduced toxicity of PPT in SLN.Pharmacokinetics study displayed a higher blood concentration,a prolonged circulation time,and an increased bioavailability of PPT-SLN compared with those of PPT.Our results demonstrated that PPT-SLN could optimize pharmacokinetics,enhance antitumor activity and attenuate toxicity,so it has a promising prospect for the application in anti-tumor treatment. To evaluate the antitumor activity and pharmacokinetics of podophyllotoxin (PPT) incorporated into solid lipid nanoparticles (SLN), Kunming mice inoculated with flesh tumor were used as animal model. Mice with a single daily intraperitoneal injection of PPT in 20% ethanol (5 mg Gross tumor and body weight and clinical observations were recorded daily. The mice were sacrificed for 24 h after the last administration, and the tumor inhibition rate was (/ mg / kg in PPT) for 3 weeks calculated with the tumor weight. For the pharmacokinetics research, the mice were treated with intraperitoneal injection of PPT (10 mg / kg) and PPT-SLN (10 mg / kg in PPT). Blood samples were collected at different times to determine the PPT concentration in plasma by HPLC .lood drug level-time curve was made and pharmacokinetic parameters were calculated. As a result of drug administration, the tumor volume and weight of the mice injected with PPT-SLN were significantly restrained compared with mice tr eated with PPT or negative control. The tumor inhibition rate of 58.13% showed a significant antitumor activity of PPT-SLN. At the same time, the increased weight gain of the mice injected with PPT-SLN suggested a reduced toxicity of PPT in SLN. It has been demonstrated that PPT-SLN could optimize pharmacokinetics, enhance antitumor activity and attenuate toxicity, so it has has promising prospect for the application in anti-tumor treatment.