Labeling and biodistribution of 99mTc-7-bromo-1,4-dihydro-4-oxo-quinolin-3-carboxylic acid complex

7-Bromo-1,4-dihydro-4-oxo-quinolin-3-carboxylic acid (BDOQCA), was synthesized with a yield of 93% and well characterized. The obtained compound was investigated to label with one of the most important radioactive isotopes (technetium-99m). Effect of BDOQCA concentration, stannous chloride dihydrates (SnCl 2 .2H 2 O) concentration, pH and reaction time on the percent labeling yield of 99m Tc-BDOQCA complex was studied in details. 99m Tc-BDOQCA complex was obtained at a maximum yield of 97.3% by mixing 2.5 mg of BDOQCA with 25 μg SnCl 2 .2H 2 O at pH 6 and 30 min reaction time and the formed complex was stable for a time up to 8 h with a maximum yield of 97.3%. Biodistribution studies in mice were carried out using experimentally induced infection in the left thigh using E. coli. Both thighs of the mice were dissected and counted to evaluate the ratio of bacterial infected thigh/contralateral thigh. Higher uptake in the infected thigh was observed after 2 h of IV administration of 99m Tc-BDOQCA complex ( T/NT = 7.6 ± 0.6%) than that of the commercially available 99m Tc-ciprofloxacin complex ( T/NT = 3.8 ± 1%). The in vitro binding and biodistribution of 99m Tc-BDOQCA complex in the septic and aseptic inflammation bearing mice showed that, 99m Tc-BDOQCA complex is a promising agent for infection imaging and can differentiate between infected and inflamed muscle .