title: Influence of methyl-beta-cyclodextrin and liposomes on rheological properties of Carbopol 974P NF gels.
abstract: The influence of positively-charged and sterically stabilized liposomes and/or methyl-beta-cyclodextrin on rheological properties of Carbopol 974P NF hydrogels was investigated. All formulations have displayed a shear-thinning behavior of Carbopol gels, and the rate stress as a function of the shear rate was fitted using the Cross equation. An important loss of viscosity was observed when 1.5% Carbopol gels were formed in Hepes/NaCl buffer or in a 5% aqueous solution of methyl-beta-cyclodextrin. Nevertheless, when methyl-beta-cyclodextrin was dissolved in buffer at 5% there was no additional effect on gel viscosity reduction. The incorporation of positively-charged and sterically stabilized liposomes at 2 mM of lipid concentration had no incidence on rheological properties of the Carbopol gels, whereas gel viscosity was significantly increased in the presence of positively-charged liposomes at 10 mM of lipid concentration. Finally, the viscosity of hydrogels containing both liposomes and methyl-beta-cyclodextrin tended to be close to control gels, remaining high and relevant for a topical delivery.
authors.affiliation: UMR CNRS 8612, School of Pharmacy, Faculté de Pharmacie, Université Paris-Sud, 5 rue JB Clément, 92296 Châtenay-Malabry Cedex, France.
authors.forename: Laïla
authors.initials: L
authors.lastname: Boulmedarat
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Grossiord
authors.forename: Elias
authors.initials: E
authors.lastname: Fattal
authors.forename: Amélie
authors.initials: A
authors.lastname: Bochot
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D004337:Drug Carriers; D004355:Drug Stability; D006531:HEPES / Q000378:metabolism; D066298:In Vitro Techniques; D008081:Liposomes / Q000737:chemistry*; D012212:Rheology; D014783:Viscosity; D047392:beta-Cyclodextrins
chemical_list: D000179:Acrylates; D003505:Cyclodextrins; D004337:Drug Carriers; D008081:Liposomes; D047392:beta-Cyclodextrins; C117167:carbopol 974P NF; C108732:methyl-beta-cyclodextrin; D006531:HEPES