Highly fluorinated metal complexes as dual <sup>19</sup>F and PARACEST imaging agents
作者:Meng Yu、Bailey S. Bouley、Da Xie、Emily L. Que
DOI:10.1039/c9dt01852b
日期:——
water-soluble transition metal complexes that can serve as both 19F and PARACEST magnetic resonance imaging agents. The high number of equivalent fluorine atoms and the paramagnetic effect of metals offer these complexes high 19F sensitivity as demonstrated by in vitro19F MRI experiments. The complexes contain carboxamide groups appended onto a cyclen macrocycle, which provide 1H CEST peaks well differentiated
我们报道了一组水溶性过渡金属配合物,可以同时用作19 F和PARACEST磁共振成像剂。大量的当量氟原子和金属的顺磁性效应为这些配合物提供了很高的19 F敏感性,这在体外19 F MRI实验中得到了证明。该配合物含有附加在cyclon大环上的羧酰胺基,可提供与大量水区分开的1 H CEST峰。Co(II)试剂显示两个CEST峰,可用于比率pH值测定,Fe(II)证明了结合19 F MR和PARACEST作为互补成像技术的概念) 复杂的。
Solution Structure and Relaxivity of Ln‐DOTXAZA Derivatives
作者:Malte Holzapfel、Torben Baldau、Svenja Kerpa、Gianmarco Guadalupi、Bing Qi、Yang Liu、Wolfgang J. Parak、Wolfgang Maison
DOI:10.1002/ejic.202200432
日期:2022.11.17
Gd-Based contrast agents (GBCAs) are essential reagents in clinical diagnosis via MRI. We report four members of the DOTXAZA series, which are valuable scaffolds for the assembly of new GBCAs with improved relaxivity and tailored pharmacokinetic or targeting properties by Cu-catalyzed alkyne-azide cycloaddition (CuAAC).
Highly regioselective N-trans symmetrical diprotection of cyclen
作者:Luis M. De León-Rodríguez、Zoltan Kovacs、Ana Cristina Esqueda-Oliva、Alma Delia Miranda-Olvera
DOI:10.1016/j.tetlet.2006.07.135
日期:2006.9
A high yielding N-trans diprotection procedure for cyclen has been developed by using succinimide carbarnate derivates of Boc and Cbz and chloroformate protecting groups. (c) 2006 Elsevier Ltd. All rights reserved.
Design of Ga–DOTA-based bifunctional radiopharmaceuticals: Two functional moieties can be conjugated to radiogallium–DOTA without reducing the complex stability
From the X-ray crystal structures of Ga-DOTA chelates, we were able to deduce that two free carboxylate groups of the radiogallium-DOTA complex may be utilized for coupling to functional moieties that recognize molecular targets for in vivo imaging without reducing the radiogallium-complex stability. Thus, we designed 2,2'-[4,10-bis(2-[2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethyl]amino}-2-oxoethyl)1,4,7,10-tetraazacyclododecane-1,7-diyl]diacetic acid (DOTA-MN2) (7), employing a metronidazole moiety as the recognition site of hypoxic lesions, based on the drug design concept of bifunctional radiopharmaceuticals. Coupling of DOTA-bis(tert-butyl) ester 5 with 1-(2-aminoethyl)-2-methyl-5-nitroimidazole dihydrochloride, followed by deprotection, afforded the required 7 (DOTA-MN2). Ga-67-labeling was carried out by reaction of DOTA-MN2 with Ga-67-citrate. When Ga-67-DOTA-MN2 was incubated in phosphate-buffered saline or mouse plasma, no measurable decomposition occurred over a 24-h period. In biodistribution experiments in NFSa tumor-bearing mice, Ga-67-DOTA-MN2 displayed not only a significant tumor uptake, but also rapid blood clearance and low accumulations in nontarget tissues, resulting in high target-to-nontarget ratios of radioactivity. These results indicate the potential benefits of the drug design of Ga-67-DOTA-MN2. The present findings provide helpful information for the development of radiogallium-labeled radiopharmaceuticals for SPECT and PET studies. (C) 2009 Elsevier Ltd. All rights reserved.