Macromolecular contrast agents for magnetic resonance imaging. Influence of polymer content in ligand on the paramagnetic properties.
Macromolecular conjugates of Gd3+-diethylenetriaminepentaacetic acid with dextran were synthesized from dextran 40 (about 40 kg/mol). Diethylenetriaminepentaacetic acid (DTPA) was coupled to aminated dextran by means of a watersoluble carbodiimide and macromolecular conjugates containing DTPA ratios as high as 1.25 mmol/g of polymer were obtained. First, it was found that the polymer had a favourable influence on relaxivity, as at 20 MHz, the r1 longitudinal relaxivity of the Gd3+-complexed macromolecular conjugates was 2 to 4 times as great as that of free GdDTPA2-, depending on the DTPA content. Second, r1 greatly increased with the increase in the conjugate DTPA content, from 7.4 to 15.9 mM-1s-1 for an increase in the DTPA content from 0.36 to 0.96 mmol/g. Further increase in the ligand content had no more effect on relaxivity.
Rebizak
R
R
Laboratoire de Chimie-Physique Macromoléculaire, UMR 7568, ENSIC-INPL, BP 451, 54001 Nancy Cedex, France.
Schaefer
M
M
Dellacherie
E
E
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003287:Contrast Media / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D019786:Gadolinium DTPA / Q000737:chemistry*; D008024:Ligands; D008279:Magnetic Resonance Imaging; D011108:Polymers
D003287:Contrast Media; D008024:Ligands; D011108:Polymers; D019786:Gadolinium DTPA