[⁴⁵Ti]Ti-HOPOs: Potential Complexes for the Development of ⁴⁵Ti PET Imaging Agents

Area of Science:

• Radiochemistry
• Nuclear Medicine
• Biomedical Imaging

Background:

• Titanium-45 (⁴⁵Ti) possesses favorable characteristics for Positron Emission Tomography (PET) imaging, including a suitable half-life and positron emission decay.
• The radiochemistry of ⁴⁵Ti, particularly the development of bifunctional chelators, remains underexplored compared to other radiometals.

Purpose of the Study:

• To investigate hydroxypyridinone compounds as potential chelators for ⁴⁵Ti.
• To optimize radiolabeling, assess stability, and evaluate biodistribution of ⁴⁵Ti complexes.

Main Methods:

• Synthesis and evaluation of three hydroxypyridinone chelators: C8-HOPO, C9-HOPO, and C10-HOPO.
• Radiolabeling optimization studies with ⁴⁵Ti.
• In vitro stability assays and in vivo biodistribution studies in animal models.

Main Results:

• C9-HOPO emerged as a promising chelator for ⁴⁵Ti.
• Optimized radiolabeling conditions were established.
• The ⁴⁵Ti-C9-HOPO complex exhibited excellent stability and rapid clearance in vivo without evidence of decomplexation.

Conclusions:

• C9-HOPO is a suitable bifunctional chelator for developing ⁴⁵Ti-based radiopharmaceuticals for PET imaging.
• Further research into ⁴⁵Ti radiochemistry is warranted to fully exploit its potential in medical imaging.