Preparation, Biodistribution, and Scintigraphic Evaluation of ⁹⁹ᵐTc-Clindamycin: an Infection Imaging Agent

Bacterial infection is found to be the cause of death throughout the world. Nuclear medicine imaging with the help of radiopharmaceuticals has great potential for treating infections. In the present work, clindamycin, a lincosamide antibiotic, was labeled with technetium-99 m (~380 MBq). Clindamycin has been proven to be efficient for treating serious infections caused by bacteria such as Staphylococcus aureus. Quality control, characterization, biodistribution, and scintigraphy of radiolabeled clindamycin were done, and labeling efficiency was determined by ascending paper chromatography. More than 95 % labeling efficiency with technetium-99 m (⁹⁹ᵐTc) was achieved at pH 6–7 while using 2.5–3 μg SnCl₂ · H₂O as a reducing agent and 100 μg of ligand at room temperature. The characterization of the compound was performed by using electrophoresis, HPLC and shake flask assay. Electrophoresis indicates the neutral behavior of ⁹⁹ᵐTc-clindamycin. HPLC analysis confirms the single specie of the labeled compound, while shake flask assay confirms high lipophilicity. The biodistribution studies of ⁹⁹ᵐTc-clindamycin were performed Sprague Dawley rats bearing bacterial infection. Scintigraphy and biodistribution studies showed a high uptake of ⁹⁹ᵐTc-clindamycin in the liver, heart, lung, and stomach as well as at S. aureus-infected sites in rabbits.