Preparation and analysis of 99mTc moxifloxacin as an infection specific imaging agent.

Preparation and analysis of 99mTc moxifloxacin as an infection specific imaging agent.
Kashani, R.; Cooper, M.S.; Das, S.S.
April 2004
Nuclear Medicine Communications. 25(4):413-414
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Aim: To prepare a novel radiopharmaceutical (99mTc moxifloxacin) as a potential bacteria specific infection imaging agent.
Methods: Moxifloxacin was radiolabelled with 99mTc by a number of different methods. Variables included choice of co-ligand, choice of reducing agent, inclusion of antioxidant, temperature for incubation, time of incubation and pH. Radiopharmaceutical 'cold' kits were prepared by dissolving the kit constituents in nitrogen purged water for injection followed by lyophilization. A formulation including moxifloxacin, stannous chloride, sodium lactate and nitrogen gave the best radiolabelling efficiency. After addition of sodium pertechnetate the kit was heated at 100[degrees]C for 10 min. Quality control analysis was performed by ITLC and HPLC.
Results: Radiolabelling efficiency was poor (10-15%) and filtration through a 0.2 [mu]m filter followed by purification by HPLC was required to obtain pure product. However, quality control analysis of the purified 99mTc moxifloxacin showed >95% purity with 2.2% immobile impurities and 2.5% mobile impurities by ITLC. HPLC was in line with ITLC results showing a single peak with a small impurity (free pertechnetate) at the solvent front.
Conclusion: Although 99mTc moxifloxacin could be prepared in a pure stable form, due to low radiolabelling efficiencies, alternative labelling methods need to be explored in order to establish its usefulness as an infection imaging agent.
(C) 2004 Lippincott Williams & Wilkins, Inc.