Synthesis, Biodistribution And Evaluation Of Tc-99m-Sitafloxacin Kit: A Novel Infection Imaging Agent

Radiosynthesis of Tc-99m-sitafloxacin (Tc-99m-STF) complex and its efficacy as a potential infection imaging agent was evaluated. Effect of sitafloxacin (STF) concentration, sodium pertechnetate ((NaTcO4)-Tc-99m), stannous chloride dihydrate (SnCl2 center dot 2H(2)O), and pH on the % radiochemical purity yield (RCP) of Tc-99m-STF complex was studied. A stable Tc-99m-STF complex up to 120 min with maximum %RCP yield was observed by mixing 2 mg of STF with 3 mCi of (NaTcO4)-Tc-99m and 150 mu L of SnCl2 center dot 2H(2)O (1 mu g/mu L in 0.01 N HCl) at a pH 5.5. Artificially infected rats with Staphylococcus aureus were used for studying the biodistribution behavior of the Tc-99m-STF complex. After 30 min of the intravenous (I.V.) administration of the Tc-99m-STF complex, 7.50 +/- A 0.10% was absorbed in the infected thigh of the rats and the uptake gradually increased to 18.50 +/- A 0.20% within 90 min. Rabbits with artificially induced infection were used for evaluating the scintigraphic accuracy. Higher uptake in the infected thigh was observed after 2 h of I.V. administration of the Tc-99m-STF complex. Target to non-target organ ratio of the % absorbed dose incase of infected/normal muscle was 6.82 +/- A 0.40, 17.11 +/- A 0.60, and 23.13 +/- A 1.00% at 30, 60 and 90 min of administration. Stable and higher %RCP, higher uptake in the infected thigh, and spectral studies, recommend the Tc-99m-STF for routine infection imaging.