Optimizing [99mTc]Tc-Tamsulosin for Enhanced Tumor Detection: A Comprehensive Approach from Preparation to In Vivo Evaluation

To investigate the potential of Tamsulosin hydrochloride, a selective α1-adrenoceptor antagonist, as a tumor-targeting ligand when labeled with Technetium-99 m [⁹⁹ᵐTc] for use as a novel radiopharmaceutical. This study aims to develop and evaluate the [⁹⁹ᵐTc]Tc-Tamsulosin complex for enhanced tumor imaging and improved diagnostic accuracy in oncology. The radiolabeling process was optimized using 0.6 mg of tamsulosin, 75 µg of SnCl2.2H2O and 200 µL of pH 4 buffer with 0.1 ml (350 MBq) Na[99mTcO4]−, with the mixture incubated at room temperature (25°C) for 30 min. Radiochemical yield and in vitro stability were assessed via TLC, and purification was performed through electrophoresis and high-performance liquid chromatography (HPLC), followed by in vivo evaluation studies in tumor-bearing mice versus normal mice. The [⁹⁹ᵐTc]Tc-Tamsulosin complex achieved a radiochemical purity of 97.5 ± 0.12% and maintained in vitro stability in serum and PBS above 87 ± 0.22% after 24 h. In vivo evaluation revealed peak tumor uptake (T) of 5.2 ± 0.02% ID/g and normal muscle (NT) uptake of 0.98 ± 0.01% ID/g at 2 h post-injection, with a target-to-non-target ratio of 5.3. Renal clearance was prominent, with kidney uptake of 16 ± 0.24% ID/g and urinary excretion reaching 25 ± 1.37% ID/g at 3 h. The [⁹⁹ᵐTc]Tc-Tamsulosin complex demonstrates high radiolabeling efficiency, stability, and selective tumor accumulation, supporting its potential as a promising radiopharmaceutical for accurate tumor imaging. These findings highlight its value in advancing nuclear medicine oncology diagnosis.