title: Optimization of lipid composition in cationic emulsion as in vitro and in vivo transfection agents.
abstract: OBJECTIVE
  To enhance in vitro and in vivo transfection activity by optimizing lipid composition of cationic lipid emulsions.
  
  
  METHODS
  Various emulsion formulations having different cationic lipids as emulsifiers, and additional helper lipids as co-emulsifiers, were prepared. The stability of the emulsion and its complex with DNA was investigated by measuring the particle size change in phosphate buffer saline (PBS) over a period of 20 days. The activity of the emulsions in transfecting pCMV-beta into COS-1 cells in the presence or absence of 80% serum was evaluated. We also evaluated in vivo transfection activity using intravenously administered pCMV-Luc+ as a reporter gene.
  
  
  RESULTS
  Among the cationic emulsifiers, 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) formed the most stable and efficient emulsion gene carrier. Addition of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) increased in vitro transfection activity, but slightly compromised the stability of the emulsion. The loss was compensated for by including small amounts of Tween 80 in the emulsion. The in vitro and in vivo transfection activities were also increased by adding Tween 80. Even though in vitro transfection activity of liposomes was high in the absence of serum, the transfection activity of emulsions was far greater than that of liposomes in the presence of serum and for in vivo applications.
  
  
  CONCLUSIONS
  By including DOPE as an endosomolytic agent and Tween 80 as a stabilization agent, the cationic emulsion becomes a more potent gene carrier for in vitro and in vivo applications, especially in the presence of serum.
authors.affiliation: Biomedical Research Center, Korea Institute of Science and Technology, Seoul.
authors.forename: T W
authors.initials: TW
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Chung
authors.forename: I C
authors.initials: IC
authors.lastname: Kwon
authors.forename: H C
authors.initials: HC
authors.lastname: Sung
authors.forename: S Y
authors.initials: SY
authors.lastname: Jeong
mesh_terms: D016475:3T3 Cells; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D019556:COS Cells; D004337:Drug Carriers; D004655:Emulsions; D005079:Excipients / Q000493:pharmacokinetics*; D005229:Fatty Acids, Monounsaturated / Q000493:pharmacokinetics*; D005260:Female; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D015870:Gene Expression / Q000502:physiology; D018014:Gene Transfer Techniques; D020404:Glycerophospholipids / Q000493:pharmacokinetics*; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000493:pharmacokinetics; D008081:Liposomes; D051379:Mice; D008807:Mice, Inbred BALB C; D010714:Phosphatidylethanolamines; D010957:Plasmids / Q000235:genetics / Q000493:pharmacokinetics; D011136:Polysorbates / Q000493:pharmacokinetics*; D000644:Quaternary Ammonium Compounds / Q000493:pharmacokinetics*; D014162:Transfection / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D000956:Antigens, Viral; D004337:Drug Carriers; D004655:Emulsions; D005079:Excipients; D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D020404:Glycerophospholipids; D017874:Immediate-Early Proteins; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011136:Polysorbates; D000644:Quaternary Ammonium Compounds; C044582:immediate-early proteins, cytomegalovirus; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane