A comparison of labelling characteristics of manual and automated synthesis methods for gallium-68 labelled ubiquicidin

A decade of ubiquicidin development for PET imaging of infection: A systematic review

“…This review provides strong evidence of gallium-68 UBI (29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41) and its other derivatives being selective and specific imaging agents of bacterial infections. Labelling procedures are uncomplicated and fast and there are sufficing indications of good stability.…”

“…Following the discovery of UBI 1-59 (6600 g/mol) several linear peptide fragments were identified, namely UBI 18-35 , UBI [22][23][24][25][26][27][28][29][30][31][32][33][34][35] , and UBI 31-38 and UBI 29-41. All of these fragments retained antimicrobial activity despite the lower molecular weight. However, UBI 31-38 (RAKRRMQY) and UBI [29][30][31][32][33][34][35][36][37][38][39][40][41] (TGRAKRRMQYNRR) have been mainly suggested as the most viable fragments due to better biological properties during their initial in vivo investigations. These two peptides are different from each other in length, size and net charge (UBI 29-41 = 13-mer, 1692 g/mol, +7 vs. UBI 31-38 = 8-mer 1107 g/mol; +5) but both show both good water solubility [29].…”

“…Evidence for more regulated production was found in 2 publications using cold kit starting material for reconstitution with gallium-68 (i.e., radiopharmaceutical compounding) and 3 publications reporting a fully remote automated procedure with relevance to GMP production. Interestingly, the automatic synthesis as well as kit labelling procedure was directly compared in 1 research article [32].…”

“…The eluates from various origins were buffered by either sodium acetate (0.5 -5 M) or N-2-Hydroxyethylpiperazine-N'-2ethanesulfonic acid (HEPES) buffer. Various radical scavengers to optimize the radiolabelling efficiency were investigated by Le Roux et al, [32]. For all radio syntheses described, the incubation times varied from 10-15 minutes at temperatures ranging from 85 -100 °C.…”

“…Manual synthesis is most often used during these investigations, and this indicates that the technology readiness level of these radiopharmaceuticals is definitely not at a stage for commercial production. Thus, studies by Le Roux et al, [32,35] and Vilche et al [38] deserve special mention since automation was investigated on the Scintomics and Eckhard and Ziegler automated synthesis units. Good Manufacturing Practice (GMP) aspects are also addressed by Vilche et al, [38].…”