64CU-COMPLEX OF THE BIFUNCTIONAL CHELATOR WITH PSMA TARGETING MOLECULE IN EX VIVO BIODISTRIBUTION STUDY IN HEALTHY RATS

Abstract

Тhe development of new diagnostic radioactive biochemical products and effective therapeutic radiopharmaceuticals is very important in the era of a personalized approach in the management of cancer patients. Consistent expression of prostate specific membrane antigen (PSMA) in metastatic prostate cancer helps us in finding the relevant radioactive prostate-specific membrane antibody. The radiopharmaceuticals used in molecular imaging require a simple radiolabeling (radiosynthesis) procedure, good target-to-organ sensitivity, and metabolic stability. The aim of this study was to label bifunctional chelator, DOTA, covalently bound to a PSMA targeting vector (DOTAGA-(I-y)fk(Sub-KuE)) with Copper-64 (64Cu) and to examine its physicochemical properties and pharmacokinetic characteristics. Healthy adult rats of Wistar strain were used to carry out experiments through ex vivo biodistribution with intravenous radiopharmaceutical administration of (7±1.5) MBq. Target organs and tissues were harvested 60 min post-injection. Also, in vitro radiochemical stability of radiolabeled molecule 64Cu-DOTA-PSMA was studied with TLC method, 24 h post preparation of the product. The obtained data showed a low uptake (≤0.45 % IA g-1) in the majority of organs, except for the liver (1.21±0.48 % IA g-1) and the kidneys (6.10±0.98 % IA g-1),indicating them as clearance organs. The in vitro stability study confirmed a relatively highstability and the product can be safely used during thatperiod.