Toward improved syntheses of dendrimer-based magnetic resonance imaging contrast agents: new bifunctional diethylenetriaminepentaacetic acid ligands and nonaqueous conjugation chemistry.
Toward improved syntheses of dendrimer-based magnetic resonance imaging contrast agents: new bifunctional diethylenetriaminepentaacetic acid ligands and nonaqueous conjugation chemistry.
复制标题
DOI：
10.1021/jm061324m
复制
发表时间：
2007-06
影响因子：
7.3
通讯作者：
Heng-Wei Xu;C. Regino;M. Bernardo;Y. Koyama;Hisataka Kobayashi;P. Choyke;M. Brechbiel
中科院分区：
文献类型：
--
作者：
Heng-Wei Xu;C. Regino;M. Bernardo;Y. Koyama;Hisataka Kobayashi;P. Choyke;M. Brechbiel
Two different fourth-generation (G4) polyaminonamido dendrimer-based magnetic resonsance (MR) agents were prepared by a new synthetic approach wherein tert-butyl-protected forms of 2-(4-isothiocyanatobenzyl)-6-methyldiethylenetriamine pentaacetic acid (1B4M-DTPA), bearing either an isothiocyanate or a succinimidyl ester moiety, respectively, were conjugated to the primary amines of the dendrimer. Purification was facilitated using a solid phase, N-(2-aminoethyl)aminomethyl polystyrene. After Gd(III) incorporation, molar relaxivity measurements of both new dendrimer-based agents as compared to a G4 agent prepared by an aqueous chemistry route indicated no significant changes in relaxivity. Comparative MR imaging revealed equivalent enhancement of the vessels and organs such as the kidney and liver, although slightly different vascular clearance rates were observed. This general synthesis provides a procedure for preparation of dendrimer-based MR agents for clinical applications with higher yields and efficiency while enhancing versatility. The latter aspect is further demonstrated by preparation of a novel maleimide analog of 1B4M-DTPA from a key synthetic intermediate aniline derivative.
