Preparation and evaluation of a single vial AMBA kit for 68Ga labeling with potential for imaging of GRP receptor-positive cancers

This study describes the development of a lyophilized kit formulation of AMBA (DO3A-CH2CO-G-[4-aminobenzoyl]-QWAVGHLM-NH2), a bombesin analog, for labeling with 68Ga from an in-house nanoceria–polyacrylonitrile based 68Ge/68Ga generator and from a commercial 68Ge/68Ga generator, for imaging the gastrin-releasing peptide (GRP) receptors over-expressed in a variety of human cancers. 68Ga-AMBA could be prepared in high radiochemical purity (97 ± 1.1 %) and exhibited high in vitro stability. Biodistribution studies in normal Swiss mice showed high pancreatic uptake (15.5 ± 1.5 % ID g−1) which reduced in presence of cold peptide (3.5 ± 0.7 % ID g−1), confirming the specificity of the 68Ga-AMBA prepared using the kit to GRP receptors.