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

The PTX-loaded micelles were synthesized and characterized in vitro and in vivo that the size, appearance, stability and sensitivity to different pH were demonstrated. On benefit of suitable particle size and sensitivity to acidic environment, we proved that PTX-loaded micelles could target solid cancer after intravenously injected into tumor-bearing mice and release PTX when they entered the cells. The anticancer ability of paclitaxel was enhanced both in vitro and in vivo when it was encapsulated in micelles prepared by PEG-TPP. [Display omitted] 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.