Development of new copper-64 labeled rhodamine: a potential PET myocardial perfusion imaging agent

Norah AlHokbany; Ibrahim AlJammaz; Basem AlOtaibi; Yousif AlMalki; Bander AlJammaz; Subhani M Okarvi

doi:10.1186/s41181-022-00171-2

Development of new copper-64 labeled rhodamine: a potential PET myocardial perfusion imaging agent

EJNMMI Radiopharm Chem. 2022 Jul 23;7(1):19. doi: 10.1186/s41181-022-00171-2.

Authors

Norah AlHokbany^{1

2}, Ibrahim AlJammaz³, Basem AlOtaibi³, Yousif AlMalki³, Bander AlJammaz^{4

5}, Subhani M Okarvi³

Affiliations

¹ Chemistry Department, Science College, King Saud University, P.O. Box 22452, Riyadh, 11495, Kingdom of Saudi Arabia. nhokbany@ksu.edu.sa.
² College of Medicine, King Saud University, P.O. Box 22452, Riyadh, 11495, Kingdom of Saudi Arabia. nhokbany@ksu.edu.sa.
³ Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh, 11211, Kingdom of Saudi Arabia.
⁴ Chemistry Department, Science College, King Saud University, P.O. Box 22452, Riyadh, 11495, Kingdom of Saudi Arabia.
⁵ College of Medicine, King Saud University, P.O. Box 22452, Riyadh, 11495, Kingdom of Saudi Arabia.

Abstract

Background: Myocardial perfusion imaging (MPI) is one of the most commonly performed investigations in nuclear medicine procedures. Due to the longer half-life of the emerging positron emitter copper-64 and its availability from low energy cyclotron, together with its well-known coordination chemistry, we have synthesized ⁶⁴Cu-labeled NOTA- and ⁶⁴Cu-NOTAM-rhodamine conjugates as potential cardiac imaging agents using PET.

Results: ⁶⁴Cu-NOTA- and ⁶⁴Cu-NOTAM-rhodamine conjugates were synthesized using a traightforward and one-step simple reaction. Radiochemical yields were greater than 97% (decay corrected), with a total synthesis time of less than 25 min. Radiochemical purities were always greater than 98% as assessed by TLC and HPLC. These synthetic approaches hold considerable promise as a simple method for ⁶⁴Cu-rhodamine conjugates synthesis, with high radiochemical yield and purity. Biodistribution studies in normal Fischer rats at 60 min post-injection, demonstrated significant heart uptake and a good biodistribution profile for both the radioconjugates. However, the ⁶⁴Cu-NOTAM-rhodamine conjugate has shown more heart uptake (~ 10% ID/g) over the ⁶⁴Cu-NOTA-rhodamine conjugate (5.6% ID/g).

Conclusions: These results demonstrate that these radioconjugates may be useful probes for the PET evaluation of MPI.

Keywords: Copper-64; Myocardial perfusion imaging; Positron emission tomography; Radiopharmaceuticals; Rhodamine.