Estrogen receptor targeting with genistein radiolabeled Technetium-99m as radiotracer of breast cancer: Its optimization, characterization, and predicting stability constants by DFT calculation.

Objective: Genistein is an isoflavone molecule with a high affinity for estrogen receptors (ER), which could lead to the mechanism of selective estrogen receptor modulators (SERMs) in breast cancer. Genistein labeling with technetium-99m can be a new promising strategy for diagnostic breast cancer. In this research, we evaluate the physicochemical characteristics of the [99mTc]Tc-genistein complex and describe the optimal labeling method parameters. We also calculated density functional theory to study the stability constants to support complex formation analysis (DFT). Methods: The genistein was directly labeled with 99mTc, and its stability as well as its potential for usage as a radiotracer were all investigated. DFT calculations with thermodynamic cycles to determine chemical coordination models and calculate thermodynamic constants of complex more accurately. Results: The radiochemical purity of [99mTc]Tc-genistein showed a high yield of 93.25% ± 0.30% and had good physicochemical properties. The stability of the Tc(IV)-genistein complex was confirmed by DFT calculations at a value of 99.0822. Conclusions: As a result, [99mTc]Tc-genistein could be a potential radiotracer kit for SPECT imaging of breast cancer.