Concentrating dopamine in liposomes using transmembrane gradient of ammonium sulfate

: The active loading of liposomes from egg phosphatidylcholine and cholesterol with dopamine using an ammonium sulfate gradient was studied. Our conditions allowed the enrichment of the monolamellar liposomes with 90% dopamine added to the medium and, thus, considerably improve the dopamine/lipid ratio. Dopamine-containing liposomes with tocopherol in their lipid bilayer were shown to be stable for 3 weeks.