Facile purification and click labeling with 2-[¹⁸F]fluoroethyl azide using solid phase extraction cartridges

Area of Science:

• Radiochemistry
• Organic Chemistry
• Medical Imaging

Background:

• Positron Emission Tomography (PET) relies on radiotracers for disease diagnosis.
• Efficient synthesis and purification of PET tracers are crucial for clinical application.
• 2-[18F]fluoroethyl azide ([18F]FEA) is a versatile precursor for 18F-labeled radiotracers.

Purpose of the Study:

• To develop a facile and efficient method for purifying [18F]FEA.
• To enable both solution-phase and solid-phase click labeling using purified [18F]FEA.
• To demonstrate the compatibility of the method with automated synthesis platforms for PET tracer development.

Main Methods:

• Purification of [18F]FEA using a sequential C18 and Oasis® HLB cartridge system.
• Elution of purified [18F]FEA for subsequent solution-phase click reactions.
• Direct on-cartridge click labeling by loading alkyne substrate and catalyst onto the HLB cartridge.

Main Results:

• [18F]FEA was exclusively trapped and purified on the Oasis® HLB cartridge.
• High yields were achieved for both solution-phase and on-cartridge click labeling.
• The method proved to be safe, simple, and reproducible.

Conclusions:

• A robust solid-phase extraction methodology was established for [18F]FEA purification and click labeling.
• This approach facilitates the automated synthesis of 18F-labeled PET tracers.
• The developed method offers a safe, efficient, and versatile tool for radiopharmaceutical development.