Abstract: OBJECTIVE To study the pharmacokinetics of 18α-GL solid lipid nanoparticles(18α-GL-SLN). METHODS Implanted microdialysis probes into the femoral vein and liver of rats, and sampling at the same time for 10 h after 18α-GL-SLN and 18α-GL solution administration. Dialysate was determined with HPLC and real 18α-GL drug concentration in blood and liver was calculated. Drug-time curve was fitted, pharmacokinetics parameters were calculated and these parameters were compared by statistical analysis. RESULT Pharmacokinetics parameters of Cmax, AUC0→T, AUCextra and MRT were significantly different in blood and liver after 18α-GL-SLN and 18α-GL administration. Compared wih 18α-GL solution, 18α-GL-SLN had lower Cmax in blood, higher Cmax, longer MRT and higher AUC in liver. CONCLUSION Concentration of 18α-GL in liver increases significantly and the MRT becomes longer after 18α-GL-SLN administration. Experiment shows that 18α-GL-SLN has distinguished liver target characteristics.