99mTc‐tricabonyl labeling of ofloxacin and its biological evaluation in Staphylococcus aureus as an infection imaging agent

Even in recent decades, one of the major causes of death and unhealthiness in the whole world is infection and inflammation. The use of radiopharmaceuticals is a powerful tool in managing the patients with infectious diseases. In this study, ofloxacin as a second‐generation fluoroquinolone has been labeled with [^99mTc(CO)₃(H₂O)₃]⁺ core to formulate a suitable infection imaging agent. Ofloxacin was radiolabeled with ^99mTc using carbonyl core. Radioligand chemical analysis involved HPLC methods. Radioconjugate stability and lipophilicity were determined. Binding with Staphylococcus aureus and biodistribution in infected mice for labeled compound were studied. The radioligand was characterized by HPLC, and its radiochemical purity was more than 90%. In vitro stability studies have shown the complex was stable at least 6 h after labeling at room temperature. The n‐octanol/water partition coefficient experiment exhibited logP = 1.52 ± 0.21 for ^99mTc(CO)₃‐ofloxacin. The complex showed specific binding to S. aureus. Biodistribution results showed that radioligand had high accumulation in the infected muscle in a mice (T/NT = 2.02 ± 0.12 at 4 h postinjection). On the basis of stability and infection site uptake ratio, suitability of this complex as a radiotracer for imaging of infections is recognized.