High relaxivity linear Gd(DTPA)-polymer conjugates: The role of hydrophobic interactions

被引:47
作者
Kellar, KE
Henrichs, PM
Hollister, R
Koenig, SH
Eck, T
Wei, D
机构
[1] RELAXOMETRY INC,MAHOPAC,NY
[2] DARTMOUTH HITCHCOCK MED CTR,DEPT RADIOL,HANOVER,NH
[3] SANOFI RES DIV,MALVERN,PA
[4] MERCK RES LABS,W POINT,PA
关键词
Gd(DTPA)(2-); hydrophobic interactions; linear polymer; relaxivity;
D O I
10.1002/mrm.1910380506
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
A series of linear copolymers of DTPA-class Gd3+ conjugates, linked by alpha,omega-alkyldiamides with a varying number (n) of methylenes separating the amide function, were synthesized, Surprisingly, their relaxivities at all fields increased with increasing n. At MRI fields and 35 degrees C, the relaxivities of the n = 10 and n = 12 polymers were unexpectedly high, similar to those of rigid dendrimer-based Gd3+ chelates, The magnetic field dependence of solvent proton 1/T-1, was measured for aqueous urea-free and urea-containing polymer solutions, The results for urea-free solutions imply an increase of rigidity (required for high relaxivities) with increasing n, arising from hydrophobic interactions of the methylene groups with solvent, This hypothesis is supported by a large decrease in the relaxivities upon addition of urea, which is known to weaken hydrophobic interactions, The relaxivities are also independent of polymer concentration, indicating that the hydrophobic interactions are intramolecular.
引用
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页码:712 / 716
页数:5
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