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Published on: May 29, 2017
Radiosynthesis of [18F]-flumazenil Using an Isotopic Approach
Riptee Thakur1, Aishwarya Kumar1, Raman Kumar Joshi1
1Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
Background:
Fluorine-18 (18F) flumazenil (FMZ) has been synthesized using various precursors, and its role has been explored in imaging Gamma-aminobutyric acid-A receptors.
Aim And Objective:
The main objective was to synthesize (18F) FMZ using isotopic substitution.
Materials And Methods:
Around 18 ± 2 GBq was added to the module, dried, and radiolabeling was standardized with 3.0 mg of the FMZ precursor at various temperatures (110°C -160°C) for 10-30 min. The product was finally eluted with 20% ethanol (in phosphate buffer). The final product was characterized by high-performance liquid chromatography (HPLC). The stability was evaluated in water, saline, and phosphate-buffered saline for 4 h.
Results:
The radiolabelling efficiency of cartridge-based purification was 16 ± 4% (n = 10) with a radiochemical purity of 96.5 ± 1.8%, whereas in HPLC-based purification, the yield was 10 ± 4% (n = 5) with a radiochemical purity of 97.3 ± 1.4%. The specific activity was 120 ± 20 GBq/μmol.
Conclusions:
(18F) FMZ was successfully synthesized using an isotopic approach and could be used as an alternative cheaper option for the synthesis.
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