Incorporation of α-tocopherol in dimyristoylphosphatidylcholine liposomes improves the survival of fibroblasts in culture

The use of liposomes as carriers for certain drugs minimizes the adverse effects of high drug concentrations. However, the liposomes themselves mag exert toxic effects on human cells, depending on their composition and concentration. The aim of the present investigation was to compare the effects of dimyristoylphos-phatidylcholine (DM-PC) liposomes with those of DM-PC liposomes containing alpha-tocopherol on human fibroblasts in culture. DM-PC liposomes had a dose-dependent effect on the growth of fibroblasts in culture, showing high toxicity at a phospholipid concentration of 300 mu M. The incorporation of alpha-tocopherol in the liposome bilayer significantly improved cell survival in the presence of high DM-PC liposome levels. The results demonstrate that alpha-tocopherol is able to reduce the negative effects of high phospholipid concentrations and perhaps permit the use of liposome concentrations that would otherwise be toxic.