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A new tetrapodal 3-hydroxy-4-pyridinone ligand for complexation of 89 zirconium for positron emission tomography (PET) imaging

Christian Buchwalder, Cristina Rodríguez-Rodríguez, Paul Schaffer, Stoyan K Karagiozov, Katayoun Saatchi, Urs O Häfeli

Dalton Trans. 2017 Jul 25;46(29):9654-9663.

PMID: 28713886

Abstract:

Zirconium-89 (89Zr) is an ideal radiometal isotope for antibody-based positron emission tomography (immunoPET) as its physical half-life (3.27 days) is a good match with the biological half-life of larger molecular weight targeting molecules, such as antibodies (3-4 days), and its positron emission (BR = 100% EC/β+, Eβ+,avg = 395.5 keV) is suited for high resolution PET imaging. Concerns over the in vivo stability of the most commonly used 89Zr-chelator, desferrioxamine B (DFO), have spurred efforts into the development of alternative 89Zr-chelators that withstand the release of osteophilic 89Zr4+. Herein we report the new chelator 1,3-propanediamine-N,N,N',N'-tetrakis[(2-(aminomethyl)-3-hydroxy-1,6-dimethyl-4(1H)-pyridinone)acetamide] (THPN) based on four 3-hydroxy-4-pyridinone (3,4-HOPO) coordinating groups, as a potentially superior chelator over DFO. THPN has been demonstrated to quantitatively form a monometallic complex with Zr4+ within 10 min at ambient temperature at as low as 10-6 M concentrations of the chelator. The resulting complexes were studied in vitro and in vivo. The 89Zr-THPN complex was stable in serum and outperformed the 89Zr-DFO complex in a direct transchelation challenge. Healthy mice excreted 89Zr-THPN rapidly without signs of demetalation or residual organ uptake. This renders THPN as a promising alternative to DFO and introduces the first octadentate 3,4-HOPO chelator to the field.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP100079263 THPN THPN 100079-26-3 Price
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