Synthesis of N₄'-[¹⁸F]fluoroalkylated ciprofloxacin as a potential bacterial infection imaging agent for PET study
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Published on: May 29, 2017
Kalme Sachin1, Eun-Mi Kim, Su-Jin Cheong
1Department of Nuclear Medicine, Cyclotron Research Center, Research Institute of Clinical Medicine, Chonbuk National University Medical School, Jeonju, Jeonbuk 561-712, Korea.
Abstract:
Syntheses and evaluation of fluoroalkylated ciprofloxacin analogues are described. Among these analogues, N₄'-3-fluoropropylciprofloxacin (16) showed the most efficient antibacterial activity against E. coli strains (DH5α and TOP10) and a high binding affinity for DNA gyrase of bacteria. To develop bacteria-specific infection imaging agents for positron emission tomography (PET), no-carrier-added N₄-3-[¹⁸F]fluoropropylciprofloxacin ([¹⁸F]16) was prepared in two steps from N₄-3-methanesufonyloxypropylciprofloxacin, resulting in a 40% radiochemical yield (decay corrected for 100 min) via the tert-alcohol media radiofluorination protocol with high radiochemical purity (> 99%) as well as high specific activity (149 ± 75 GBq/μmol). The agent was stable (> 90%), as shown by an in vitro human serum stability assay. A bacterial uptake and blocking study of [¹⁸F]16 using authentic compound 16 in TOP10 cells demonstrated its high specific bacterial uptake. The results suggest that this radiotracer holds promise as a useful bacterial infection radiopharmaceutical for PET imaging.
Insights
Researchers developed a novel fluoroalkylated ciprofloxacin analogue, [¹⁸F]16, for bacterial infection imaging. This compound shows high efficacy against E. coli and is suitable for positron emission tomography (PET) imaging.
Area of Science:
- Medicinal Chemistry
- Radiopharmaceutical Chemistry
- Molecular Imaging
Background:
- Fluoroalkylated ciprofloxacin analogues are explored for enhanced antibacterial properties.
- Developing specific imaging agents for bacterial infections using positron emission tomography (PET) is crucial.
Purpose of the Study:
- To synthesize and evaluate fluoroalkylated ciprofloxacin analogues.
- To develop a novel radiotracer for PET imaging of bacterial infections.
Main Methods:
- Synthesis of N₄'-3-fluoropropylciprofloxacin and its radiolabeled form [¹⁸F]16.
- Evaluation of antibacterial activity and DNA gyrase binding affinity.
- Radiochemical synthesis using a tert-alcohol media radiofluorination protocol.
- In vitro stability assays and bacterial uptake studies.
Main Results:
- N₄'-3-fluoropropylciprofloxacin (16) demonstrated potent antibacterial activity against E. coli and high DNA gyrase affinity.
- [¹⁸F]16 was prepared with high radiochemical purity (>99%) and specific activity (149 ± 75 GBq/μmol).
- The radiotracer [¹⁸F]16 exhibited high specific bacterial uptake and stability in human serum.
Conclusions:
- The novel fluoroalkylated ciprofloxacin analogue [¹⁸F]16 is a promising candidate for PET imaging of bacterial infections.
- This radiotracer facilitates specific targeting and imaging of bacterial infections.
