title: Semi-solid fluorinated-DPPC liposomes: Morphological, rheological and thermic properties as well as examination of the influence of a model drug on their skin permeation.
abstract: The goal of this study was to investigate the influence of an incorporated model drug on the skin permeation of the vehicle itself as it may affect the microstructure and properties of the applied formulation via molecular interactions. For this purpose, we performed skin permeation studies using liposomes prepared with F-DPPC, a monofluorinated analog of dipalmitoylphosphatidylcholine (DPPC), with and without sodium fluorescein (SoFl) serving as model drug. Interestingly, the liposome preparation with F-DPPC yielded semi-solid opalescent systems. Hence, a thorough characterization was accomplished beforehand by electron microscopy imaging, rheological and thermoanalytical experiments. Freeze-fracture electron microscopy images confirmed the existence of globular shaped vesicles in the F-DPPC preparations and oscillatory rheological measurements proved the viscoelastic properties of F-DPPC and F-DPPC+SoFl liposomes in contrast to the viscous characteristics of DPPC liposomes. Thermoanalytical measurements revealed an increased phase transition temperature Tm of about 50 °C for F-DPPC and F-DPPC+SoFl liposomes compared to pure DPPC liposomes with a Tm of about 43° C. The similar Tm of F-DPPC+SoFl and F-DPPC liposomes as well as the similar skin permeation of the vehicle compound F-DPPC compared to its drug-free counterpart suggest an incorporation of sodium fluorescein into the aqueous core of F-DPPC liposomes.
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, University of Vienna, Vienna 1090, Austria.
authors.forename: Denise-Silvia
authors.initials: DS
authors.lastname: Mahrhauser
authors.affiliation: Department of Pharmacognosy, University of Vienna, Vienna 1090, Austria.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Reznicek
authors.affiliation: Electron Microscopy Facility, Campus Science Support Facilities GmbH, Dr. Bohr-Gasse 3, Vienna 1030, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Kotisch
authors.affiliation: Electron Microscopy Facility, Campus Science Support Facilities GmbH, Dr. Bohr-Gasse 3, Vienna 1030, Austria.
authors.forename: Marlene
authors.initials: M
authors.lastname: Brandstetter
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, University of Vienna, Vienna 1090, Austria.
authors.forename: Corinna
authors.initials: C
authors.lastname: Nagelreiter
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, University of Vienna, Vienna 1090, Austria.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kwizda
authors.affiliation: Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, University of Vienna, Vienna 1090, Austria; Research Platform "Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms", University of Vienna, Vienna 1090, Austria. Electronic address: claudia.valenta@univie.ac.at.
authors.forename: Claudia
authors.initials: C
authors.lastname: Valenta
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000818:Animals; D019793:Fluorescein / Q000737:chemistry*; D005461:Fluorine / Q000737:chemistry*; D066298:In Vitro Techniques; D008081:Liposomes; D008854:Microscopy, Electron; D012212:Rheology; D012869:Skin Absorption; D013552:Swine; D044366:Transition Temperature
chemical_list: D008081:Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D005461:Fluorine; D019793:Fluorescein
keywords: F-DPPC; Fluorescein sodium salt; Freeze fracture; Mass spectrometry; Skin permeation