We have previously developed a new medical material of hybrid liposomes. The hybrid liposomes can be prepared simply by applying sonication to the aqueous buffer solution which contains phospholipids and micellar surfactants ; they are free from any contamination of organic solvent, and more stable for a long time as compared with conventional liposomes. We have already demonstrated that the hybrid liposomes have an antitumor effect on lymphoma cells in vitro. Furthermore, the hybrid liposomes including lipid-soluble antitumor agent were found to markedly prolong the life span of mice model of gliorna. In this study, the uniform and stable hybrid liposomes composed of 90 mol% L-α-dimyristoylphosphatidylcholine (DMPC) and 10 mol% polyoxyethylene(10)dodecyl ether (C12(EO)10) having a hydrodynamic diameter of 80 nm were prepared for the therapeutical application. The 50 mol% inhibitory concentration of the hybrid liposomes of DMPC/10 mol% C12(EO)10, ([DMPC]=0.383 mM) on the growth of Lewis lung carcinoma cells in vitro was smaller than that of DMPC liposomes (>1 mM). A mouse model of lung carcinoma was established by intraperitoneal inoculation of Lewis lung carcinoma cells. The survival times of mice model of lung carcinoma in the control groups were 25.0 and 45.0 days for median and maximum values, respectively. On the other hand, the survival times in the treated groups with the hybrid liposomes of DMPC/10 mol% C12(EO)10 were more than one year. These results suggest that the hybrid liposomes should be effective for the treatment of lung carcinoma.
