Multi-drug delivery to tumor cells via micellar nanocarriers.

The aim of this study was to develop micellar nanocarriers for concomitant delivery of paclitaxel and 17-allylamino-17-demethoxygeldanamycin (17-AAG) for cancer therapy. Paclitaxel and 17-AAG were simultaneously loaded into polymeric micelles by a solvent evaporation method. Two candidate nanocarrier constructs, polyethylene glycol-poly(D, L-lactic acid) (PEG-PLA) micelles and PEG-distearoylphosphatidylethanolamine/tocopheryl polyethylene glycol 1000 (PEG-DSPE/TPGS) mixed micelles, were assessed for the release kinetics of the loaded drugs. Compared to PEG-PLA micelles, entrapment of paclitaxel and 17-AAG into PEG-DSPE/TPGS mixed micelles resulted in significantly prolonged release half-lives. The simultaneous incorporation of paclitaxel and 17-AAG into PEG-DSPE/TPGS mixed micelles was confirmed by (1)H NMR analysis. Paclitaxel/17-AAG-loaded PEG-DSPE/TPGS mixed micelles were as effective in blocking the proliferation of human ovarian cancer SKOV-3 cells as the combined free drugs. PEG-DSPE/TPGS mixed micelles may provide a novel and advantageous delivery approach for paclitaxel/17-AAG combination therapy.