99mTc-labeled antibiotics for infection imaging along with diagnostic potential: a comparative study of cephalosporin and fluoroquinolone

Background Technetium-99m (Tc-99m)-labeled cefixime, ceftriaxone, and ciprofloxacin are explored for stable, effective radiopharmaceutical infection imaging agents. Objective This study optimizes Tc-99m labeling of antibiotics, evaluating stability, effectiveness, and infection imaging suitability. Methods TcO₄⁻ was reduced with stannous chloride to label antibiotics; scanning electron microscope, ITLC, Fourier transform infrared spectroscopy, HPLC, and biodistribution studies confirmed purity, labeling efficacy, and infection specificity. Results Tc-99m labeling of cefixime was performed at a concentration of 5 mg/ml, using 120 µl of SnCl₂ solution (96 µg) as the reducing agent, with the pH adjusted to 4.34 using 1N NaOH. For ciprofloxacin, the concentration was 7.5 mg/ml, with 120 µl of SnCl₂ solution (96 µg) and a pH of 4.5. Ceftriaxone was radiolabeled at 5 mg/ml, using 120 µl of SnCl₂·2H₂O (50 µg) and a pH of 6.8. Radiochemical binding was monitored for 3 h to assess stability. The labeled drugs were administered to mice for SPECT scintigraphy to assess biodistribution, confirm infection imaging, and evaluate their diagnostic potential. Conclusion This study examines 99mTc labeling of cefixime, ceftriaxone, and ciprofloxacin, achieving high binding efficiency. It compares their potential in infection imaging, distinguishing infections from inflammation, and exploring therapeutic applications.