Radioiodination of Silodosin with ¹³¹I as a Selective Drug for Prostate Imaging in Mice

Background: Silodosin (Sild) is a selective α1A-adrenergic receptor antagonist effective in treating benign prostatic hyperplasia (BPH), a condition characterized by prostate enlargement, which leads to urinary dysfunction. Objective: This study aimed to radiolabel Sild with iodine-131 [¹³¹I]) using chloramine-T(Ch-T), optimized the process to achieve high radiochemical yields, and investigated the [¹³¹I]Sildodosin [¹³¹I]Sild) radiotracer in the prostate of murine models. Methods: Compared to a control group, biodistribution studies were conducted to evaluate the [¹³¹I]Sild radiotracer uptake in mice with BPH. Biochemical analyses were performed to assess serum prostate-specific antigen (PSA) levels, antioxidant enzyme activities catalase (CAT) and superoxide dismutase (SOD), and oxidative stress markers such as malondialdehyde (MDA) in both groups. Results: The [¹³¹I]Sild radiotracer exhibited a radiochemical yield of 93.7 ± 1.1% and maintained stability for up to 4 h in serum. Biochemical markers indicated an increase in PSA, lipid peroxidation, MDA levels, and protein content, with an increase in prostate weight in mice with BPH compared to the control group. Histopathological examination revealed disruption of tissue growth and a localized inflammatory response in BPH compared to the control. Biodistribution studies demonstrated significant uptake of the [¹³¹I]Silodosin radiotracer in BPH, with a value of 7.6 ± 0.18% ID/g at 120 min post-administration. Conclusion: The results suggest that [¹³¹I]Silodosin radiotracer holds potential as an imaging agent for chronic prostatic diseases, particularly BPH.