The blood-brain barrier(BBB) is formed by the brain capillary endothelium and excludes from the brain approximately 100% of large-molecule neurotherapeutics and more than 98% of all small-molecule drugs.There are three routines to increase drug transport into brain,ie,neurosurgical,pharmaceutical chemical,and physiological ways and the later is most hopeful.The receptor-mediated transcytosis system on the brain capillary endothelium could be used as multifunctional vectors for drug active transport into brain.This provides the platform for CNS drug delivery programs.

Objective To explore aescin's inhibition of in vitro proliferatim in L1210 murine acute lymphoid leukemia cells and its in vivo antileukemic effects.Methods MTT assay was used to determine the anti-proliferative effect in vitro;Leukemia transplant models were used to test the antileukemic effect. Mice inoculated with L1210 cells were treated with ten daily doses of aescin or/and each other day of DOX, and were observed for survival.Antileukemic effects were assessed by calculating the extension of lifespan. Results Aescin(20～60?g/mL) was found to be able to inhibit the proliferation of L1210 cells.The effects were in a dose- and time- dependent manner.The IC_(50) value of aescin in L1210 cells after 72 h was (24.86?2.23)?g/mL.In vivo study showed that after treating the L1210 cells bearing mice with higher, middle,and low dosage(4.5,3.5,and 2.5 mg/kg) of aescin for ten consecutive days,The extension of lifespan were 25.8%(P