A novel method of 18F radiolabeling for PET

Area of Science:

• Radiochemistry
• Nuclear Medicine
• Bioconjugation

Background:

• Traditional Fluorine-18 (18F) radiolabeling of small biomolecules is complex, requiring molecule-specific methods and lengthy production times.
• Carbon-18F bond formation is the standard, but alternative strategies are needed for efficient radiotracer development.

Purpose of the Study:

• To develop a facile and efficient method for radiolabeling peptides using an aluminum-Fluorine-18 (Al(18)F) complex.
• To evaluate the stability, biodistribution, and tumor-targeting efficacy of the novel Al(18)F-labeled peptide conjugate.

Main Methods:

• Formed the Al(18)F complex by mixing AlCl(3).6H(2)O with (18)F in a pH 4.0 buffer.
• Conjugated Al(18)F to a peptide (IMP 449) via a chelate in a one-pot reaction.
• Assessed in vitro and in vivo stability, and tumor uptake in mice using positron emission tomography (PET).

Main Results:

• The Al(18)F-IMP 449 conjugate was synthesized with 5%-20% yield.
• The Al(18)F-IMP 449 complex demonstrated high stability in vitro and rapid urinary excretion in vivo.
• Pretargeted tumor uptake was significantly enhanced (30-fold) compared to the peptide alone, with clear tumor localization observed within 30 minutes.

Conclusions:

• The developed method provides a stable and versatile platform for labeling diverse molecules with Al(18)F.
• This approach holds promise for advancing the development of novel positron emission tomography (PET) imaging agents.