title: Serum-Stable, Long-Circulating, pH-Sensitive PEGylated Liposomes.
abstract: pH-sensitive liposomes have been designed to deliver active compounds, specifically to acidic intracellular organelles, and to augment their cytoplasmic concentrations. These systems combine the protective effects of other liposomal formulations with specific environment-controlled drug release. They are stable at physiological pH, but abruptly discharge their contents when endocytosed into acidic compartments, allowing the drug to be released before it is exposed to the harsh environment of the lysosomes.Serum-stable formulations with minimal leakage at physiological pH and rapid drug release at pH 5.0 to 5.5 can be easily prepared by inserting a hydrophobically modified N-isopropylacrylamide/methacrylic acid copolymer (poly(NIPAM-co-MAA)) in the lipid bilayer of sterically stabilized liposomes. The present chapter describes polymer synthesis, as well as the preparation and characterization of large unilamellar pH-sensitive vesicles.
authors.affiliation: Faculty of Pharmacy, Université Laval, CHU de Quebec Research Center, 2705 Boul Laurier, G1V 1B3, Quebec, QC, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bertrand
authors.affiliation: Biomod Concepts, 1821B Lavoisier, Saint-Julie, J3E 1Y6, Québec, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Simard
authors.affiliation: Institute of Pharmaceutical Sciences, ETH Zürich, Vladimir-Prelog-Weg 3, HCI H 301, 8093, Zürich, Switzerland. jleroux@ethz.ch.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Leroux
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D044967:Serum / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D008081:Liposomes; D008689:Methacrylates; C008384:methacrylic acid; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols
keywords: N-Isopropylacrylamide copolymer; Triggered release; pH-sensitive liposomes