Preparation, purification and primary bioevaluation of radioiodinated ofloxacin: an imaging agent

Abstract

The broad-spectrum antibiotic agents have been demonstrated as promising diagnostic tools for early detection of infectious lesions. We set out ofloxacin (Oflo), a second-generation fluoroquinolone, for the radioiodination process. In particular, this was carried out with ¹²⁵I via an electrophilic substitution reaction. The radiochemical yield was influenced by different factors; drug concentration, different oxidizing agents, e.g. chloramine-T, iodogen and n-bromosuccinimide, pH of medium, reaction time, temperature and different organic media. These parameters were studied to optimize the best conditions for labeling with ofloxacin. We found that radiolabeling in ethanol medium showed a 70% radiochemical yield of ¹²⁵I-ofloxacin. The radioiodination was determined by means of TLC and HPLC. The cold labeled Oflo (¹²⁷I-Oflo) was prepared and controlled by HPLC. The cold labeled Oflo was also confirmed by NMR and MS techniques. Furthermore, biodistribution studies for labeled ¹²⁵I-Oflo were examined in two independent groups (3 mice in each one); control and E. Coli-injected (inflamed). The radiotracer showed a good localization in muscle of thigh for inflamed group as compared to control. In conclusion, ofloxacine might be a promising target as an anti-inflammatory imaging agent.