Preparation, Characterization, in vivo Pharmacokinetics and Tumor Inhibition Properties of PEGylated Liposomes Containing Etoposide

Liposomal formulations of a potent antitumor drug, etoposide were prepared by ethanol injection method successfully. The characteristics of the etoposide liposomes, for particle size, encapsulation efficiency, leakage ratio, ξ potential and physical stability, were evaluated. In vivo pharmacokinetics and tumor inhibition ratio of mice were also examined. The liposomes were characterized by high entrapment efficiency, uniform size distribution and moderate ξ potential. In addition, the liposomes modified by PEG₂₀₀₀-DSPE could raise the AUC and prolonged the resident time of etoposide in the blood circulating system as compared to conventional liposomes containing etoposide and free etoposide solutions, and improve the tumor inhibition ratio demonstrated by anti-tumor activity experiments.