The aim of this study was to construct novel targeting polymeric micelles. Folate-Poly (ethylenimine)-Pluronic copolymers were synthesized. A paclitaxel (PTX)-loaded mixed micelles consisting of Folate-Poly (ethylenimine)-Pluronic and Pluronic L121 copolymers have been developed. The mixed micelles showed nano-sized spherical morphology. The solubilization capacity of the mixed micelles was higher than Folate-Poly (ethylenimine)-Pluronic micelles because L121 has high solubilization capacity. MTT colorimetric test revealed that PTX in Folate-Poly (ethylenimine)-Pluronic micelles demonstrated the maximum anticancer activity. Pluronic-poly (ethylenimine) micelles and folate-modified Pluronic-poly(ethylenimine) micelles showed a marked increase of cellular accumulation compared with Pluronic P123 micelles. The biodistribution and retention of intravenously (i.v.) administered micelles to rats were determined. Folate-Poly (ethylenimine)-Pluronic micelles demonstrated enhanced pulmonary retention in rats after injection when compared to Pluronic P123 micelles.
