177Lu‐5‐Fluorouracil a potential theranostic radiopharmaceutical: radiosynthesis,quality control,biodistribution, and scintigraphy

The aim of this study is to develop ¹⁷⁷Lu‐5‐Flourouracil as a potential cancer therapeutic radiopharmaceutical. 5‐Flourouracil (5‐FU) is widely accepted as an anticancer drug of broad spectrum fame. The labeling of 5‐FU was carried out at different set of experimental conditions using high specific activity of ¹⁷⁷LuCl₃. The optimum conditions for maximum radiochemical yield was set: 5‐FU (5 mg), ¹⁷⁷LuCl₃ (185 MBq), diethylenetriaminepentaacetic acid (10 µg), reaction volume (2 mL), pH (5.5), temperature (80°C), and reaction time (20 min). The radiochemical labeling was assessed with Whatman No. 2 paper, instant thin layer chromatographic, and radio‐HPLC, which revealed >94% labeling results with sufficient stability up to 6 h. Serum stability study also showed ¹⁷⁷Lu‐5‐FU promising stability. Biodistribution study in normal rats and rabbits showed liver, stomach, kidney, and heart as area of increased tracer accumulation just after injection, which decreased to 1.4%, 0.4%, 0.2%, and 0.39% ID/g, respectively, after 72 h. Glomerular filtration rate and cytotoxicity study results of ¹⁷⁷Lu‐5‐FU showed it had no adverse effect on renal function and nontoxic to blood cells. The promising characteristics of ¹⁷⁷Lu‐5‐FU, that is, clever elimination from kidney and nontoxic nature toward blood cells make it the radiopharmaceutical for further testing in patients for therapeutic purposes.