Labeling of Aspirin with 99m Tc to Obtain a Possible Tumor Imaging Agent

About 35% reduction in cancer deaths among patients having solid tumors is related to using aspirin, which encouraged us to develop a new specific tumor diagnostic radiopharmaceutical agent. This can be done by direct labeling of aspirin with technetium-99m using stannous chloride as a reductant at pH 9. At this pH, aspirin is saponificated to salicylate ions. Salicylate binds to pertechenetate to form 99m Tc salicylate complex. The radiochemical yield (RCY, %) of 99m Tc-salicylate complex obtained from aspirin was determined using paper chromatography, electrophoresis, and HPLC and was found to reach 90.2%. The 99m Tc salicylate complex obtained from aspirin was stable for up to 5 h. The tumor uptake of the 99m Tc salicylate complex obtained from aspirin was determined by ex-vivo study in tumor-bearing mice. This study showed that 99m Tc salicylate complex was concentrated in tumor sites (ascites or solid), allowing tumor radioimaging. High target/non-target (tumor muscles/normal muscles) uptake ratio shows that 99m Tc salicylate complex can be utilized for early detection of solid tumors. Molecular modeling and docking study conofirm the possibility of using the radiolabeled 99m Tc salicylate complex for specific cancer imaging in binding with epidermal growth factor receptors (EGFR).