Self-assembled nanoparticles of poly(lactide)--Vitamin E TPGS copolymers for oral chemotherapy

Nanoparticles (NPs) of poly(lactide)-Vitamin E TPGS (PLA-TPGS) copolymers were synthesized by a dialysis method in the present study to formulate paclitaxel for oral chemotherapy with Caco-2 cells as an in vitro model of the gastrointestinal (GI) drug barrier. The PLA-TPGS NPs were of size 340nm in diameter with 5.2% drug loading. The drug release kinetics showed a 31% initial burst in the first day, followed by 80% accumulative drug release after 30 days in the PBS buffer at pH 7.4, and the release rate was found lower in simulated gastric and intestinal conditions. The internalization of fluorescent PLA-TPGS NPs by Caco-2 cells was visualized by confocal laser scanning microscopy (CLSM). PLA-TPGS NPs showed significant increase in the cellular uptake by 1.8- and 1.4-fold in comparison with poly(lactide-co-glycolide) (PLGA) NPs cultured with HT-29 and Caco-2 cells, respectively, and the cellular uptake efficiency was found affected by the incubation time and the particle concentration in the culture medium. Investigation on HT-29 and Caco-2 cytotoxicity showed advantages of the PLA-TPGS NP formulation versus Taxol. The IC(50) of the PLA-TPGS NP formulation with HT-29 cells was found 40% lower than of Taxol at the same dose of paclitaxel. The results obtained in this research demonstrated feasibility for the PLA-TPGS NPs to be applied for oral delivery of paclitaxel as well as other anticancer drugs.