A water-insoluble anti-tumor agent, paclitaxel (PTX) was successfully incorporated into noveltargeted polymeric micelles based on tocopherol succinate-chitosan-polyethylene glycol-folic acid (PTX/TS-CS-PEG-FA). The aim of the present study was to evaluate the pharmacokinetics, tissue distribution and efficacy of PTX/TS-CS-PEG-FA in comparison to Anzatax Õ in tumor bearing mice. The micellar formulation showed higher in vitro cytotoxicity against mice breast cancer cell line, 4T1, due to the folate receptor-mediated endocytosis. The IC 50 value of PTX, a concentration at which 50% cells are killed, was 1.17 and 0.93 mM for Anzatax Õ and PTX/TS-CS-PEG-FA micelles, respectively. The in vivo anti-tumor efficacy of PTX/TS-CS-PEG-FA, as measured by reduction in tumor volume of 4T1 mouse breast cancer injected in Balb/c mice was significantly greater than that of Anzatax Õ . Pharmacokinetic study in tumor bearing mice revealed that the micellar formulation prolonged the systemic circulation time of PTX and the AUC of PTX/TS-CS-PEG-FA was obtained 0.83-fold lower than Anzatax Õ . Compared with Anzatax Õ , the V d , T 1/2ß and MRT of PTX/TS-CS-PEG-FA was increased by 2.76, 2.05 and 1.68-fold, respectively. As demonstrated by tissue distribution, the PTX/TS-CS-PEG-FA micelles increased accumulation of PTX in tumor, therefore, resulted in anti-tumor effects enhancement and drug concentration in the normal tissues reduction. Taken together, our evaluations show that PTX/TS-CS-PEG-FA micelle is a potential drug delivery system of PTX for the effective treatment of the tumor and systematic toxicity reduction, thus, the micellar formulation can provide a useful alternative dosage form for intravenous administration of PTX.
KeywordsBiodistribution, in vivo anti-tumor effect, Paclitaxel, pharmacokinetics, targeted polymeric micelle History