Biodistribution and Antitumor Effect of Adriamycin Encapsulated in Long-Circulating Liposomes Containing Amphipathic Polyethylene Glycol or Ganglioside GM1

Abstract
Biodistribution and antitumor effect of adriamycin (ADM) encapsulated in liposomes with reduced uptake by reticuloendothelial system (RES) and prolonged circulation time were investigated in mice. Two different types of long-circulating liposomes, ganglioside GMI (GMl)/distearoyl phosphatidyl choline (DSPC) /cholesterol (CH) (0.13:1:1, m/m) and amphipathic polyethylene glycol (PEG)/DSPC/CH (0.13:1:1, m/m) were used. They were sized to 180-200 nm in mean diameter. In the case of amphipathic PEG, distearoyl phosphatidylethanolamine (DSPE) derivatives of PEG with various molecular weight (1000-12000 in mean molecular weight) were used. ADM was encapsulated by transmembrane pH gradient method. GM~DSPC /CH