Comparative Biological Evaluation of 99mTc-Timonacic Acid Prepared Using Different Reducing Agents as a Complex for Hepatobiliary Imaging

Abstract

Timonacic acid (TCA) was labeled with ^99mTc in the presence of three different reducing agents: NaBH₄, Na₂S₂O₄, and SnCl₂·2H₂O. The optimum conditions were as follows: with Na₂S₂O₄, pH 8, 7 mg of Na₂S₂O₄, room temperature, 2 mg of TCA, 30 min (radiochemical yield 98 ± 0.3%, complex was stable for 24 h); with NaBH₄, pH 8, 10 mg of NaBH₄, room temperature, 2 mg of TCA, 30 min (radiochemical yield 95 ± 0.3%, complex was stable for 6 h). The biodistribution of the complex in mice was studied. The liver uptake depends on the reducing agent used, reaching in 30 min 33.5 ± 0.3, 18.4 ± 0.18, and 22.3 ± 0.3% ID/g for the complexes prepared using Na₂S₂O₄, NaBH₄, and SnCl₂·2H₂O, respectively.