title: Oil-in-water liposomal emulsions: characterization and potential use in vaccine delivery.
abstract: Emulsification of mineral oil by phospholipids donated by liposomes composed of dimyristoyl phosphatidylcholine, dimyristoyl phosphatidylglycerol, cholesterol, and lipid A by extrusion resulted in the formation of oil-in-water liposomal emulsions containing a substantial number of intact liposomes. Increasing the proportion of liposomes from 25 mM to 150 mM phospholipid and increasing the oil content from 2.5% (v/v) to 42.5% (v/v) changed the flow characteristics of the emulsions from fluid liquid-like to viscous. Likewise, the degree of stability of the emulsions was liposomal phospholipid concentration-dependent, ranging from partial emulsification in the range 25-100 mM to complete stabilization in the range 125-150 mM. Despite some loss of liposome integrity, as evidenced by the release of liposomal trapped glucose, emulsification of liposomes containing encapsulated prostate-specific antigen (PSA) exhibited antigen-specific immunostimulation in mice. These results suggest that liposomes containing encapsulated antigen can serve as constituents for the formulation of oil-in-water vaccines.
authors.affiliation: Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Muderhwa
authors.forename: G R
authors.initials: GR
authors.lastname: Matyas
authors.forename: L E
authors.initials: LE
authors.lastname: Spitler
authors.forename: C R
authors.initials: CR
authors.lastname: Alving
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D000941:Antigens / Q000276:immunology / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004337:Drug Carriers; D004355:Drug Stability; D004655:Emulsions; D004797:Enzyme-Linked Immunosorbent Assay; D005453:Fluorescence; D005947:Glucose / Q000737:chemistry; D006801:Humans; D008081:Liposomes; D051379:Mice; D008807:Mice, Inbred BALB C; D009821:Oils; D010743:Phospholipids; D017430:Prostate-Specific Antigen / Q000008:administration & dosage / Q000276:immunology; D013268:Stimulation, Chemical; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D014612:Vaccines / Q000008:administration & dosage*; D014783:Viscosity; D014867:Water
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D004337:Drug Carriers; D004655:Emulsions; D008081:Liposomes; D009821:Oils; D010743:Phospholipids; D014612:Vaccines; D014867:Water; D017430:Prostate-Specific Antigen; D005947:Glucose