title: Solubilizing effects caused by alkyl pyridinium surfactants in phosphatidylcholine liposomes.
abstract: The solubilization of neutral and electrically charged liposomes by a series of alkyl pyridinium surfactants (alkyl chain lengths C10-C14) was investigated. Solubilization was detected as a decrease in static light-scattering of liposome suspensions. Two parameters were regarded as corresponding to the effective surfactant/lipid molar ratios at which the surfactant saturated the liposomes Re(sat) and led to a complete solubilization of these structures Re(sol). From these parameters the corresponding surfactant partition coefficients were determined. The Re and K parameters fell as the surfactant alkyl chain length decreased or both the critical micellar concentration (CMC) and the hydrophilic/lipophilic balance (HLB number) increased, regardless of the bilayers electrical charge. Thus, although decyl-pyridinium bromide (DePB) showed the highest ability for saturation and solubilization of bilayers, its concentration was always higher than that needed for dodecyl-pyridinium bromide (DoPB) and tetradecyl-pyridinium bromide (TePB), the last one being the most active. These results emphasize the influence of the hydrophilic/lipophilic balance of these surfactants on liposome solubilization and the minor influence of the electrostatic factors in this process.
authors.affiliation: Departamento de Tensioactivos, Consejo Superior de Investigaciones Científicas (C.S.I.C.), C/ Jordi Girona, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: de la Maza
authors.forename: J L
authors.initials: JL
authors.lastname: Parra
mesh_terms: D000588:Amines / Q000737:chemistry; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D010712:Phosphatidic Acids / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000737:chemistry*; D012542:Scattering, Radiation; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D000588:Amines; D008081:Liposomes; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D011726:Pyridinium Compounds; D013501:Surface-Active Agents; C009317:stearylamine