Radiolabeling and evaluation of ⁶⁴⁺⁶⁷Cu-2,2'-(1,2,4-Oxadiazole-3,5-diyl)di aniline as a theranostic agent for solid...

Copper-64 (⁶⁴Cu) and Copper-67 (⁶⁷Cu) are promising theranostic isotopes for PET imaging and targeted radiotherapy. In this study, 2,2'-(1,2,4-Oxadiazole-3,5-diyl)di aniline (ODDA) was successfully radiolabeled with ⁶⁴⁺⁶⁷Cu, achieving high radiolabeling yield (97.0 ± 0.8%) and excellent stability in serum over five days. The optimized radiolabeling conditions included a ligand concentration of 30 µg, pH 4, a reaction time of 15 min, and a temperature of 60 °C. The biodistribution study in Ehrlich ascites carcinoma-bearing mice showed an initial tumor uptake of 7.8 ± 0.4%ID/g at 0.5 h, peaking at 18.0 ± 0.3ID/g at 2 h, confirming selective tumor accumulation. The log P value of -0.8 indicated a hydrophilic nature, leading to predominant renal clearance. Molecular docking studies showed strong binding to EGFR (-9.1 kcal/mol) and VEGFR2 (-8.6 kcal/mol), suggesting potential anticancer activity.