Purpose: The aim of this study is to develop novel polylactide/poly(ethylene glycol) (PLA/PEG) micelles as carrier of hydrophobic drug (paclitaxel) by direct dissolution method without using any organic solvents. The in vitro and in vivo release properties were studied in comparison with micelles prepared by dialysis.
Methods: Drug encapsulation efficiency (EE) and loading content (LC) of the micelles were evaluated by high-performance liquid chromatography. Micelle diameters and structures were determined by dynamic light scattering and transmission electron microscopy. In vitro release was performed in phosphate-buffered saline (pH 7.4) at 37 degrees C, and in vivo experiments were realized in lung cancer-bearing mice.
Results: Similar EE and LC values were obtained for micelles by direct dissolution method and those by dialysis. L- and D-PLA/PEG mixed micelles present higher drug encapsulation ability than separate micelles due to stereocomplexation. Micelle diameters are enlarged by drug-loading. Faster drug release was obtained for micelles by direct dissolution than those by dialysis. Compared with current clinical formulation and micelles by dialysis, paclitaxel-loaded micelles by direct dissolution showed the highest antitumor ability.
Conclusion: The L- and D-PLA/PEG mixed micelles by direct dissolution method present many advantages such as easy formulation and absence of toxic organic solvents, which shows great potential as carrier of hydrophobic drugs.