Radiosynthesis and preclinical studies of 177Lu-labeled sulfadiazine: a possible theranostic agent for deep-seated bacterial infection

Sulfadiazine acts through inhibition of bacterial dihydropteroate synthetase. The radio-labeling of sulfadiazine with lutetium-177 (177Lu) is expected to serve as a theranostic agent for deep-seated bacterial infections. The radiosynthesis of 177Lu-sulfadiazine indicated a > 95% yield under optimized reaction conditions, and promising stability was found in blood serum. Biodistribution data in the absence of infection revealed minimal accumulation in key body organs. Kidneys were the main excretory organs, showed an uptake of 1.76 ± 0.09% ID/g organ at 6-h post-injection. Biodistribution, scintigraphic data, glomerular filtration rate, and cytotoxicity results encourage clinical investigation of 177Lu-sulfadiazine as a novel theranostic agent for deep-seated bacterial infection.