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Gadolinium and dysprosium chelates of DTPA‐amide‐dextran: synthesis, 1 H NMR relaxivity, and induced 23 Na NMR shift
Author(s) -
Chu WenJang,
Elgavish Gabriel A.
Publication year - 1995
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940080404
Subject(s) - amide , chemistry , gadolinium , dextran , dysprosium , chelation , lanthanide , ligand (biochemistry) , nuclear chemistry , nuclear magnetic resonance , inorganic chemistry , ion , chromatography , organic chemistry , biochemistry , physics , receptor
In this study the conjugated macromolecular ligand, diethylenetriaminepentaacetic acid (DTPA)‐amide‐dextran, was synthesized by attaching DTPA to the dextran macromolecule (M r ∼6000) by a covalent amide bond. Subsequently, DTPA‐amide‐dextran was complexed with either of the two lanthanide metal ions dysprosium (Dy) or gadolinium (Gd). The paramagnetic 23 Na NMR shift induced by Dy(DTPA‐amide‐dextran) and the relaxivity (ρ i ) induced by Gd(DTPA‐amide‐dextran) were characterized. Dy(DTPA‐amide‐dextran) induced a 25% larger 23 Na NMR shift than that induced by Dy(DTPA). Neither the shift induced by Dy(DTPA‐amide‐dextran) nor the shift induced by Dy(DTPA) was affected by increasing levels of calcium ions in the solution. Gd(DTPA‐amide‐dextran) exhibited an in vitro ρ i of 8.4 (mM s) −1 at a 0.23 T magnetic field and 9.3 (mM s) −1 at a 0.47 T magnetic field, thus indicating a positive magnetic field dependence.