Enhancement of antitumor effect of doxorubicin by its complexation with γ-cyclodextrin in pegylated liposomes

In the present study, we examined tissue distribution and the antitumor effect of doxorubicin (DOX) after intravenous injection of the pegylated liposomes entrapping the DOX complex with γ-cyclodextrin (γ-CyD) (complex-in-liposome) in BALB/c mice bearing colon-26 tumor cells, compared with those of DOX solution, pegylated liposomes entrapping DOX alone (DOX-in-liposome), pegylated liposomes entrapping γ-CyD (CyD-in-liposome) and the binary system of DOX-in-liposome and CyD-in-liposome. When injected to the mice, complex-in-liposome provided the high DOX levels in plasma and solid tumors, compared with the other preparations. Reflecting the result, complex-in-liposome elicited the retardation of tumor growth and the improvement of survival rate without suppression of increase in the body weight of mice. These results suggest the potential use of pegylated liposomes entrapping the DOX complex with γ-CyD for a promising carrier for improvement of antitumor effects of DOX.