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Preparation of 68 Ga‐Mg‐Ca ‐phytate colloid and its evaluation as a liver imaging agent
Author(s) -
Tsopelas Chris,
Hsieh William
Publication year - 2017
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.3530
Subject(s) - chemistry , biodistribution , colloid , radiochemistry , nuclear chemistry , particle size , aqueous solution , radiosynthesis , imaging agent , dispersant , spleen , chromatography , dispersion (optics) , in vitro , in vivo , biochemistry , organic chemistry , physics , microbiology and biotechnology , optics , biology , immunology
The objective of this study was to investigate the radiosynthesis of 68 Ga‐Mg‐Ca‐phytate colloid and then characterise the formulation for radiochemical purity (RCP), radioactive particle size distribution, and biodistribution in normal rats. This radiocolloid was prepared by mixing an aqueous solution of phytic acid, 68 Ga 3+ ions, a dispersant, Mg 2+ and Ca 2+ ions, and then heating the contents at 100°C for 5 minutes. After cooling the vial to 5°C, the solution was basified to pH 5 and stored in the cold. The resulting product contained 92±3% RCP 68 Ga‐colloidal particles and a low level (8±3%) of soluble 68 Ga‐Mg‐Ca‐phytate. Particle size experiments defined the radioactive particle population was 6±4% <20 nm, 90±6% 20 to 200 nm, and 4% were >200 nm in diameter. Intravenous injection of the 68 Ga‐colloid dispersion to rats resulted in 93% uptake by the liver plus spleen, 1% lungs, 1% total blood, and 6% in the carcass after 20 minutes. This optimal formulation remained stable at 5°C for 1½ hours in vitro, and it resulted in the same biodistribution as the formulation prepared at t = 0 hours. The preclinical data so far indicate that 68 Ga‐Mg‐Ca‐colloid has excellent potential as a liver imaging agent.