Antitumor activity of adriamycin-incorporated polymeric micelles of poly(γ-benzyl L-glutamate)/poly(ethylene oxide)

The multiblock copolymer composed of poly(gamma-benzyl L-glutamate) (PBLG) and poly(ethylene oxide) (PEO) was synthesized to prepare polymeric micelles as an anticancer drug carrier. Adriamycin (ADR) used as an anticancer drug was incorporated into the polymeric micelles prepared by the multiblock copolymer. The higher the drug feeding ratio, the higher the drug loading contents and the lower the drug loading efficiency. The increased drug feeding ratio resulted in increased particle sizes. At all of the formulations, particle sizes were less than 150 nm. The particles were observed as spherical shapes. ADR release from ADR-loaded polymeric micelles in vitro was decreased with an increased drug loading contents. In in vitro antitumor activity test using CT 26 tumor cells, polymeric micelles showed almost similar cytotoxicity when compared to ADR itself while polymeric micelles themselves did not affect cytotoxicity. In in vivo antitumor activity test using mice tumor xenograft model, the polymeric micelles showed improved survivability of mice with minimized weight changes and excellent tumor growth suppression efficacy. Polymeric micelles of the multiblock copolymer suggested to be a good candidate for anticancer drug delivery carrier. (C) 2008 Elsevier B.V. All rights reserved.