title: Characterization of oligosaccharide-functionalized hyperbranched poly(ethylene imine) and their complexes with retinol in aqueous solution.
abstract: Structure, internal density distribution, and size of hyperbranched poly(ethylene imine) (PEI) functionalized with various amounts of maltose (PEI-Mal) in phosphate buffer were studied by small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). The value of pH was varied in the range from 3 to 9. Virtually no effect of pH on the nanostructure was found in this interval. The SAXS results revealed a broad segmental radial density distribution, i.e. a "fluffy" globular structure rather than a distinct core-shell structure with a high-density compact core and a low-density corona. This suggests that the maltose units are rather evenly distributed both in the interior and on the surface of the species with a PEI-core of molar mass of 25,000g/mol. The DLS measurements showed that the overall size of the PEI-Mal derivatives increased as the number of maltose units in the PEI-Mal structures rises. The interaction of the hydrophobic model drug retinol with PEI or PEI-Mal derivatives was also investigated. The UV-visible spectroscopy results disclosed that the solubility of retinol in the phosphate buffer is very poor and it takes a very long time to solubilize retinol. Moreover, retinol induces aggregation of dendritic glycopolymers where the growth of aggregates occurs continuously over several days and then remains virtually constant.
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway; School of Pharmacy, Department of Pharmaceutics, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway. Electronic address: sara.bekhradnia@farmasi.uio.no.
authors.forename: Sara
authors.initials: S
authors.lastname: Bekhradnia
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway; School of Pharmacy, Department of Pharmaceutics, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway. Electronic address: naz.iram@yahoo.no.
authors.forename: Iram
authors.initials: I
authors.lastname: Naz
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway. Electronic address: reidar.lund@kjemi.uio.no.
authors.forename: Reidar
authors.initials: R
authors.lastname: Lund
authors.affiliation: Leibni-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden, Germany. Electronic address: Effenberg@ipfdd.de.
authors.forename: Christiane
authors.initials: C
authors.lastname: Effenberg
authors.affiliation: Leibni-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, D-01069 Dresden, Germany. Electronic address: applhans@ipfdd.de.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Appelhans
authors.affiliation: School of Pharmacy, Department of Pharmaceutics, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway. Electronic address: s.a.sande@farmasi.uio.no.
authors.forename: Sverre Arne
authors.initials: SA
authors.lastname: Sande
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway. Electronic address: bo.nystrom@kjemi.uio.no.
authors.forename: Bo
authors.initials: B
authors.lastname: Nyström
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry*; D012995:Solubility; D014801:Vitamin A / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D007097:Imines; D009844:Oligosaccharides; D011095:Polyethylenes; C505405:poly(ethylene imine); D014867:Water; D014801:Vitamin A
keywords: Complex formation with retinol; Hyperbranched structures; Light scattering; SAXS; “Fluffy” structures