Technetium-labeled danofloxacin complex as a model for infection imaging

Danofloxacin, a fluoroquinolone derivative antibiotic, was synthesized, successfully labeled with technetium-99m and formulated for the development of a potential diagnostic imaging agent of the bacterial infection and inflammation with higher efficiency than that of the commercially available ^99mTc-ciprofloxacin. Factors affecting the labeling yield were optimized. The radiolabeled antibiotic was subjected to preclinical assessments such as purity, stability, and pharmacokinetic investigations in animals. The biodistribution studies indicated that the uptake of ^99mTc-danofloxacin was high in the infectious lesion (T/NT = 7.2 ± 0.1) at 2 h post injection. The abscess to normal ratio indicated that the danofloxacin tracer can be used for infection diagnosis. The radiolabeled compound was cleared quickly from most of the body organs. The results displayed that ^99mTc-danofloxacin could not differentiate between infection and sterile inflammation.