Development of non-phospholipid liposomes containing a high cholesterol concentration.
We present a novel formulation of non-phospholipid liposomes formed from cholesterol and palmitic acid. Despite the fact that these two lipidic species do not form individually fluid bilayers, we show that once mixed together, fluid bilayers can be obtained and, moreover, these can be extruded using classical extrusion processes to form liposomes. The chemical analysis indicates that these liposomes contain 70 mol % cholesterol, a content that is considerably higher that the saturation limit generally reported for phospholipid bilayers. These cholesterol-rich liposomes, formed with molecules that have low toxicity in vivo, display an improved impermeability relative to that of traditional phospholipid liposomes. In addition, because of the presence of palmitic acid, the stability of the liposomes is pH-dependent, and it is possible to trigger the release of encapsulated materials by pH stimuli.
Bastiat
Guillaume
G
Department of Chemistry, Université de Montréal, C.P. 6128, Succ. Centre Ville, Montréal, Québec H3C 3J7, Canada.
Oliger
Patrick
P
Karlsson
Göran
G
Edwards
Katarina
K
Lafleur
Michel
M
D002784:Cholesterol / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D019308:Palmitic Acid / Q000737:chemistry*; D010539:Permeability; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013997:Time Factors
D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D019308:Palmitic Acid; D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine