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Facilitating access to deuterated and tritiated molecules: towards more diversity!


Researchers from the Tritium Labeling Laboratory (LMT, SCBM/DMTS) describe a hydrogen isotope labeling process that is easy to implement and whose starting point is a "simple" mixture, in a solvent, of the product to be labeled with a pre-catalyst. Explanations of this process which finds applications in many fields including drug development or medical imaging. 

Published on 6 April 2022

​The labeling of molecules by isotope exchange has applications in several sectors. For example, in drug development, a radiolabeled analogue of a drug candidate can be used to determine its fate in vivo by measuring radioactivity. Chemists at the Joliot Institute's Tritium Labeling Laboratory (LMT, SCBM / DMTS) are specialists in the development of hydrogen isotope exchange labeling methods. In an article published in the journal JACS Au, the researchers describe a new process that is easy to implement and whose starting point is a "simple" mixture, in a solvent, of the product to be labeled with a commercially available pre-catalyst.

A precedent

The team had already described a general labelling method using a commercially available iridium pre-catalyst, a transition metal of the platinum family, with remarkable catalytic properties (Hydrogen isotopes in the race for new drugs). In their new study, the researchers use as pre-catalyst a dimer of rhodium, a metal with properties close to iridium, also commercially available. As in their previous study, catalytic nanoparticles of the metal are formed simply by decomposing the dimers under a deuterium or tritium gas atmosphere, using the molecule they wish to label as a surface ligand to control the aggregation state of the resulting metal clusters. 

REPLACE IRIDIUM BY RHODIUM AND INCREASE THE RANGE OF POSSIBILITIES

With rhodium as a catalyst, isotope exchange can be performed not only on sp2 hybridized carbons (of mainly aromatic rings), as with iridium, but also on sp3 hybridized carbons (aliphatic carbons). This novelty confers three advantages. First, the team can label more "bricks" commonly used in the structure of drugs that were difficult to label until now (N-aliphatic positions, benzylic carbons). Secondly, the exchange can be done on the carbon atoms of the main metabolization sites of the active substances and allow to slow down the metabolization rate of these substances. Finally, as it is possible to incorporate more deuterium atoms on a sp3 carbon than on a sp2 carbon, it is easier to obtain the internal standards required by the pharmaceutical industry.


European fundings
This work was carried out in the framework of the FET-OPEN European project FLIX, coordinated by the CEA.

Contacts CEA-Joliot:

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