Albumin microspheres labeled with Ga-67 by chelation: concise communication

Area of Science:

• Biomaterials Science
• Radiochemistry
• Nuclear Medicine

Background:

• Albumin microspheres are utilized in various biomedical applications.
• Stable radiolabeling is crucial for effective diagnostic and therapeutic agents.
• Chelating groups enhance the binding affinity of radiometals.

Purpose of the Study:

• To synthesize albumin microspheres with covalently bound EDTA and DTPA chelating groups.
• To evaluate the efficiency and stability of Gallium-67 (Ga-67) labeling on these microspheres.
• To assess the in vivo biodistribution of Ga-67 labeled microspheres.

Main Methods:

• Synthesis of albumin microspheres functionalized with EDTA and DTPA.
• Radiolabeling of microspheres with Ga-67 via transcomplexation.
• In vitro assessment of radiolabel dissociation.
• Intravenous administration of Ga-67 DTPA microspheres in mice and subsequent biodistribution studies.

Main Results:

• High yield (97 +/- 2%) Ga-67 labeling achieved using transcomplexation.
• EDTA-functionalized microspheres exhibited minimal radiolabel dissociation over time.
• Microspheres without chelating groups showed significant radiolabel loss.
• Ga-67 DTPA microspheres showed high lung localization (84 +/- 16% at 5 min) with sustained retention (60 +/- 7% at 2 hr) in mice.

Conclusions:

• Albumin microspheres functionalized with EDTA and DTPA offer a stable platform for Ga-67 radiolabeling.
• The chelation method ensures high labeling efficiency and stability, crucial for radiopharmaceutical development.
• These microspheres show potential for targeted delivery, particularly to the lungs, warranting further investigation.