A new technique of 99mTc-ciprofloxacin kit preparation

Development of a simple and reproducible method for preparing a ciprofloxacin kit using a redox polymer, which would meet the requirements for an easy and reliable technique of labelling with 99mTc and diagnostic efficiency in scintigraphic imaging of infections.

To prepare the kit, an insoluble redox polymer containing an end alpha(beta)-alanine-N,N'-diacetate group anchored to the dextran matrix was used. The redox polymer synthesised by the authors was incubated at room temperature (10 h) with a solution of ciprofloxacin (1%) in a suspension (5%). The mixture was then filtered and dispensed into sterile vials (0.2 ml each). The kit was labelled with 99mTc for 10 min at room temperature. The radiochemical purity of the ciprofloxacin-99mTc complex was determined by ITLC and paper chromatography in relation to the following factors: pH, total content of ciprofloxacin, volume of sodium 99mTc-pertechnetate. Ciprofloxacin biodistribution was evaluated in Wistar rats with Staphylococcus aureus infection in the left inguinal region 24 h after abscess induction. Accumulation of 99mTc activity was determined both using external gamma camera imaging and counting dissected tissues 1 h after administration.

Radiochemical purity is > 95% for kit-labelling (pH 3.3-3.7). With pH 3.45, labelled ciprofloxacin shows the highest stability and radiochemical purity. The 99mTc-ciprofloxacin complex is stable for at least 8 h. In experimentally induced inflammation, the amount of accumulated 99mTc-ciprofloxacin activity is five times higher than in controls.

The developed method of 99mTc-ciprofloxacin kit preparation employs a redox polymer in a new procedure, which enables the preparation of a stable kit with a high 99mTc-labelling efficiency. The labelled kit is suitable for scintigraphic imaging of infection.