Histology and antitumor activity study of PTX-loaded micelle, a fluorescent drug delivery system prepared by PEG-TPP

Abstract We synthesized PEG-TPP as carrier to encapsulate paclitaxel (PTX) in the form of micelles to overcome its water-solubility problem. PTX-loaded micelles possess a-week stability and appropriate particle size (152.1 ± 1.2 nm) which is beneficial for enhanced permeability and retention (EPR) effect. Strong pH dependence of PTX releasing from micelles is verified by in vitro release study. At cellular level, PTX-loaded micelles can target mitochondria effectively which may results a better cytotoxicity of micelles (especially IC50 = 0.123 ± 0.035 μmol/L of micelles and 0.298 ± 0.067 μmol/L of PTX alone on MCF-7 cells). The fluorescence distributions of both isolated and sliced organs show that the micelles can effectively target tumors. Moreover, we further prove the enhanced therapeutic effects of micelles in tumor-bearing mice comparing with PTX alone. The results show that the biodegradable drug delivery system prepared by PEG-TPP can overcome the poor solubility of paclitaxel and improve its tumor targeting and antitumor activity.