title: Inulin as a carrier for contrast agents in magnetic resonance imaging.
abstract: Magnetic resonance angiography (MRA) has put forth an impetus for the development of macromolecular GdIII complexes that have a prolonged lifetime in the vascular system. Herein, we report the synthesis and GdIII complexation of a new sugar conjugate based on inulin and the DO3A ligand (DO3A = 1,4,7,10-tetraazacyclododecan-1,4,7-triacetic acid). Two API-DO3ASQ conjugates (API = O-(aminopropyl)inulin, SQ = squaric acid = 3,4-dihydroxy-3-cyclobutene-1,2-dione) with different degrees of substitution (ds = 0.7 and ds = 1.5) were prepared from API by using the diethyl ester of squaric acid as a linking agent for the DO3A chelate. The efficacies of the resulting GdIII compounds were evaluated by investigation of their water 1H longitudinal-relaxation-rate enhancements at variable field (NMRD). A dramatic increase in relaxivity was observed in the more highly substituted conjugate (ds = 1.5); this prompted us to do a variable-temperature (17)O study in order to further characterize the relaxation parameters involved in this system. [Gd(API-DO3ASQ)] shows promising properties for application as a contrast agent for MRI.
authors.affiliation: Laboratory of Applied Organic Chemistry and Catalysis, Delft University of Technology, The Netherlands.
authors.forename: D M
authors.initials: DM
authors.lastname: Corsi
authors.forename: L V
authors.initials: LV
authors.lastname: Elst
authors.forename: R N
authors.initials: RN
authors.lastname: Muller
authors.forename: H
authors.initials: H
authors.lastname: van Bekkum
authors.forename: J A
authors.initials: JA
authors.lastname: Peters
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry*; D003503:Cyclobutanes / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D006801:Humans; D007444:Inulin / Q000737:chemistry*; D018810:Magnetic Resonance Angiography; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000737:chemistry*; D010103:Oxygen Isotopes / Q000737:chemistry; D013696:Temperature
chemical_list: D002614:Chelating Agents; D003287:Contrast Media; D003503:Cyclobutanes; D006571:Heterocyclic Compounds; D006573:Heterocyclic Compounds, 1-Ring; D009942:Organometallic Compounds; D010103:Oxygen Isotopes; C420452:heptatriacontakis(O-(aminopropyl)inulin-(10-(2-ethoxy-3,4-dioxo-1-cyclobutenyl)-1,4,7,10-tetraazacyclododecan-1,4,7-triacetic acid))heptatriacontagadolinium; D007444:Inulin; D005682:Gadolinium; C030042:squaric acid