In vitro evaluation of ^99mTc‐sultamicillin for infection imaging

Abstract

Early detection of the site of infection non‐invasively with radiolabeled molecules is important for the success of treatment. Technetium‐99m labeled antibiotics have the potential to discriminate between bacterial infection and sterile inflammation. Sultamicillin is the tosylate salt of the double ester of sulbactam plus ampicillin. In this study, sultamicillin was labeled with 99mTc according to the stannous chloride method. Quality control studies of radiolabeled sultamicillin were performed by radiochromatographic methods. In vitro binding assays were performed in live and heat‐killed gram‐positive Staphylococcus aureus and gram‐negative Escherichia coli strains. The radiolabeling yield of 99mTc‐sultamicillin was determined as 97.8% ± 3.1% (n = 5). The maximum bacterial uptake of 99mTc‐sultamicillin was 80.7% ± 11.00% at 4 h for living S. aureus and 93.2% ± 4.40% at 2 h for E. coli. Bacterial uptake study results show that sultamicillin has the potential to be a nuclear imaging agent, especially in infections caused by gram‐negative E. coli and gram‐positive S. aureus.