title: Serum decreases permeability of some compounds from liposomes.
abstract: Although serum is generally regarded to increase the permeability of liposomes containing entrapped substances, we found that a low concentration of serum (10%) significantly reduced the permeability of liposomes to the spin label tempocholine chloride and the polar drug methotrexate, although it increased the permeability of the lipid-soluble drug actinomycin D. Liposomes containing sphingomyelin and cholesterol were considerably less permeable than liposomes containing phosphatidylcholine and cholesterol. Although a higher concentration of serum (88%) increased the permeability of liposomes containing either lipid, the amount of tempocholine which had leaked from sphingomyelin-containing liposomes in 88% serum after 50 h at 37 degrees C was only 25%, three times less than that from phosphatidylcholine-containing liposomes. Thus the effect of serum on liposome permeability depends on the compound entrapped as well as the type of lipid used.
mesh_terms: D000818:Animals; D002417:Cattle; D003497:Cyclic N-Oxides / Q000032:analysis; D003609:Dactinomycin / Q000032:analysis; D007106:Immune Sera / Q000032:analysis*; D008081:Liposomes / Q000032:analysis*; D008727:Methotrexate / Q000032:analysis; D010539:Permeability
chemical_list: D003497:Cyclic N-Oxides; D007106:Immune Sera; D008081:Liposomes; D003609:Dactinomycin; C017743:tempocholine; D008727:Methotrexate