Feasibility and availability of 68Ga-labelled peptides

Abstract

(68)Ga has attracted tremendous interest as a radionuclide for PET based on its suitable half-life of 68 min, high positron emission yield and ready availability from (68)Ge/(68)Ga generators, making it independent of cyclotron production. (68)Ga-labelled DOTA-conjugated somatostatin analogues, including DOTA-TOC, DOTA-TATE and DOTA-NOC, have driven the development of technologies to provide such radiopharmaceuticals for clinical applications mainly in the diagnosis of somatostatin receptor-expressing tumours. We summarize the issues determining the feasibility and availability of (68)Ga-labelled peptides, including generator technology, (68)Ga generator eluate postprocessing methods, radiolabelling, automation and peptide developments, and also quality assurance and regulatory aspects. (68)Ge/(68)Ga generators based on SnO(2), TiO(2) or organic matrices are today routinely supplied to nuclear medicine departments, and a variety of automated systems for postprocessing and radiolabelling have been developed. New developments include improved chelators for (68)Ga that could open new ways to utilize this technology. Challenges and limitations in the on-site preparation and use of (68)Ga-labelled peptides outside the marketing authorization track are also discussed.

68Ga-NOTA-UBI-29-41 as a PET Tracer for Detection of Bacterial Infection

“…The dissection of infected muscle in aseptic conditions and its homogenization and culture were performed to confirm the presence of infection and to correlate the specific uptake of 68 Ga-NOTA-UBI-29-41 with the colony-forming units of Optimization of Labeling Parameters. For pH evaluation, we used the range recommended (3.5-4.5) in the bibliography (1,8,12,13,15), in which the effect of pH in the labeling with 68 Ga is thoroughly analyzed. We also tested several buffer pH settings and concentrations to achieve robust conditions for the labeling, reaching optimal conditions for pH in the recommended range and minimizing salt concentration.…”

“…This radiopharmaceutical is nontoxic and has a half-life of 68 min, making it suitable for peptide pharmacology. 68 Ga is available from 68 Ge/ 68 Ga generators without using a cyclotron (8). The introduction of bifunctional macrocyclic complexing agents has led to agents with slower rates of decomposition (9,10).…”

Radiolabelled peptides in diagnosis and therapy: an introduction

“…Decristoforo et.al. [3] discuss the status of 68 Ge/ 68 Ga generators, automated radiopharmaceutical preparations and quality parameters. They also highlight the factors influencing the feasibility and availability of this technique in an increasingly demanding regulatory environment worldwide.…”

New neurotensin analogue radiolabeled by 99m‐technetium as a potential agent for tumor identification

“…[29] It has been shown that labeling with the association of both coligands will result in mild labeling conditions, higher specific activity, higher stability, and more hydrophilicity of radiopeptide. [24,30,31] These properties will result in better in vivo pharmacokinetic (such as lower liver uptake, higher renal excretion, and faster blood clearance) for radiopeptide. Additionally, tricine/EDDA complexes show lower protein binding than tricine alone.…”

“…Additionally, tricine/EDDA complexes show lower protein binding than tricine alone. [31] Therefore, we decided to evaluate an analogue of NT-20.3 [2] through easily accessible 99m-technetium radioisotope and HYNIC. In addition, we added an extra β-alanine amino acid between Pro 7 -Arg 8 residues.…”