Transmetalation methods for the synthesis of PET and SPECT imaging agents

A process for the preparation of a radionuclide imaging agent, comprising:

• providing an imaging agent comprising a chelated place-holder metal from Row 5 or 6 of the Periodic Table of Elements;
• loading the imaging agent onto a stationary phase stable to an acidic solution comprising a dilute aqueous solution of strong acid, pKa<about 2, in a concentration of about 1.0 M or less or a solution of a weak organic acid, pKa>about 2 and <about 5, in a concentration of about 5.0 M or less;
• binding the loaded imaging agent onto the stationary phase;
• reacting the chelated place-holder metal by flowing an acidic solution comprising a dilute aqueous solution of strong acid, pKa<about 2, in a concentration of about 1.0 M or less or a solution of a weak organic acid, pKa>about 2 and <about 5, in a concentration of about 5.0 M or less through the stationary phase sufficient to remove the place-holder metal from the stationary phase bound imaging agent;
• binding a replacement radioactive metal to the stationary phase bound imaging agent so as to replace the chelated place-holder metal of the imaging agent loaded on the stationary phase with the replacement radioactive metal;
• and
• eluting the imaging agent comprising the chelated replacement radioactive metal from the stationary phase to provide a radionuclide imaging agent suitable for positron emission tomography or single-photon emission computed tomography.