Docetaxel prodrug liposomes for tumor therapy: characterization, in vitro and in vivo evaluation

There is a strong desire to develop docetaxel (DTX) formulation with good therapeutic effectiveness in view of serious adverse reactions of the commercial formulation of DTX (Taxotere (R)). In this study, a redox-responsive DTX-vitamin E prodrug was successfully formulated into liposomes with the drug loading of 4.14% +/- 0.10%. Compared with DTX liposomes, the DTX prodrug liposomes (DPLs) showed good stability for 30-d shelf life and during dilution with different media. In vitro antitumor activity of DPLs on human prostatic carcinoma PC-3 cells and human lung cancer A549 cells was evaluated using cytotoxicity and apoptosis assays. In spite of a decrease in in vitro antitumor activity, the in vivo pharmacokinetic study reveals that DPLs exhibit significantly longer DTX plasma half-life (t(1/2), 1.38-fold) and higher bioavailability (AUC(0-t), 14.49-fold) compared with DTX liposomes. The antitumor activity of DPLs to the A549 tumor xenograft model showed selective accumulation in tumor tissue, significant inhibition the growth of the tumors and a much lower toxicity as seen in body weight loss, compared with DTX-Solution. Taken together, the results showed that DPLs is a promising strategy for DTX antitumor delivery.