Study on antitumor activity of paclitaxel-loaded polymeric micelles

Objective To develop paclitaxel-loaded polymeric micelles from poly (e-caprolactone)-poly (ethylene glycol)-poly(e-caprolactone) (PCL-PEG-PCL),and to evaluate in vitro cytotoxicity as well as in vivo antitumor activity against EMT-6 tumor breast cell.Methods Paclitaxel-loaded polymeric micelles were prepared by thin-film hydration and ultrasonic method.The physical status of paclitaxel inside the polymeric micelles was investigated by differential scanning calorimetry (DSC).In vitro cytotoxicity of paclitaxel-loaded polymeric micelles against EMT-6 cell line was assessed by MTT assay.In vivo anticancer activity was evaluated against EMT-6 tumorbearing mice,with commercially available Taxol injection as control.Results Paclitaxel-loaded polymeric micelles exhibited homogeneous spherical shapes with apparent core-shell morphology.The average diameter of paclitaxelloaded polymeric micelles was 93 nm.DSC study indicated that paclitaxel was in solid amorphous state after being encapsulated in the polymeric micelles.In vitro cytotoxicity demonstrated that the cytotoxic effect of paclitaxelloaded polymeric micelles was lower than that of Taxol injection at the same paclitaxel content.Paclitaxel-loaded polymeric micelles showed greater tumor growth-inhibition effect in vivo on EMT-6 breast tumor in comparison with that of Taxol injection,with tumor growth inhibition of 85.79％ and 63.37％,respectively (P＜0.05).Conculsions The prepared paclitaxel-loaded polymeric micelles showed high anti-tumoral efficacy and low toxicity,and might have the potential to be developed as an effective anticancer drug-delivery system for cancer chemotherapy. Key words: Polymeric micelles;  PCL-PEG-PCL;  Paclitaxel;  Anti-tumoral effect