Improvement of End-of-Synthesis Radiochemical Purity of Lu-DOTA-PSMA-Ligands with Alternative Synthesis Approaches: Conversion Upswing and Side-Products Minimization.

Background: Radiochemical purity is a key criterion for the quality of radiopharmaceuticals used in clinical practice. The joint improvement of analytical methods capable of identifying related radiochemical impurities and determining the actual radiochemical purity, as well as the improvement of synthesis methods to minimize the formation of possible radiochemical impurities, is integral to the implementation of high-tech nuclear medicine procedures. PSMA-targeted radionuclide therapy with lutetium-177 has emerged as an effective treatment option for prostate cancer, and [Lu]Lu-PSMA-617 and [Lu]Lu-PSMA have achieved global recognition as viable radiopharmaceuticals.

Radiolysis-Associated Decrease in Radiochemical Purity of Lu-Radiopharmaceuticals and Comparison of the Effectiveness of Selected Quenchers against This Process.

The radiolytic degradation of vector molecules is a major factor affecting the shelf life of therapeutic radiopharmaceuticals. The development of time-stable dosage forms of radiopharmaceuticals is the key to their successful implementation in clinical practice. Using [Lu]Lu-PSMA-617 molecule as an example, the time dependence of the change in radiochemical purity (RCP, %) under radiolysis conditions was studied.

Synthesis, Complexation Properties, and Evaluation of New Aminodiphosphonic Acids as Vector Molecules for Ga Radiopharmaceuticals.

Two new aminodiphosphonic acids derived from salicylic acid and its phosphonic analogue were prepared through a simple and efficient synthesis. 2-[(2-Amino-2,2-diphosphono)ethyloxy]-benzoic acid and 2-[(2-amino-2,2-diphosphono)ethyloxy]-5-ethyl-phenylphosphonic acid were evaluated for their applicability as Ga binding bone-seeking agents. Protonation constants of and and stability constants of the Ga complexes with and in water were determined.