Chemical impurities in [18F]FDG preparations produced by solid-phase 18F-fluorination

Area of Science:

• Radiochemistry
• Analytical Chemistry
• Nuclear Medicine

Background:

• Positron emission tomography (PET) relies on radiotracers like 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG).
• Ensuring the purity of [18F]FDG is critical for accurate diagnostic imaging and patient safety.
• Solid-phase synthesis methods are commonly employed for [18F]FDG production.

Purpose of the Study:

• To determine and quantify the chemical impurities present in [18F]FDG preparations.
• To validate the purity of [18F]FDG produced using the solid-phase 18F-fluorination (resin) method.
• To identify expected and unexpected chemical byproducts in the synthesis.

Main Methods:

• Production of [18F]FDG using the solid-phase 18F-fluorination (resin) method.
• Analysis of chemical impurities using ion chromatography.
• Quantification of specific impurities including D-glucose, 2-chloro-2-deoxy-D-glucose, and D-mannose.

Main Results:

• The major chemical impurities identified were D-glucose (90.5 ± 6.4 μg/mL), 2-chloro-2-deoxy-D-glucose (11.8 ± 2.7 μg/mL), and D-mannose (1.7 ± 0.7 μg/mL).
• A small amount of FDG mass (0.5 ± 0.2 μg/mL) was also detected.
• No significant radiochemical impurities, such as 2-[18F]fluoro-2-deoxy-D-mannose, were found.

Conclusions:

• The solid-phase 18F-fluorination method yields [18F]FDG with quantifiable levels of expected chemical impurities.
• Ion chromatography is an effective method for determining chemical purity in [18F]FDG preparations.
• The study confirms the absence of notable radiochemical impurities, supporting the quality of the synthesized [18F]FDG.