The active loading of liposomes from egg phosphatidylcholine and cholestero
l with dopamine using an ammonium sulfate gradient was studied. Our conditi
ons allowed the enrichment of the monolamellar liposomes with 90% dopamine
added to the medium and, thus, considerably improve the dopamine/lipid rati
o. Dopamine-containing liposomes with tocopherol in their lipid bilayer wer
e shown to be stable for 3 weeks.