Development and evaluation of a rapid analysis for HEPES determination in 68Ga-radiotracers
Tóm tắt
HEPES is a favorable buffer for 68Ga-complexations in radiochemical laboratories. The drawback of this buffer is its prescribed limit of 200 μg per recommended application volume in the final formulation. Currently, a TLC test according to the European Pharmacopoeia (Ph. Eur.) has to be performed for quantification, but this analysis suffers from low reliability and reproducibility and is based on a subjective, semi-quantitative visual evaluation. In this study, the TLC method according to the Ph. Eur. and two literature-known HPLC assays for HEPES quantification were evaluated. Additionally, the development of an improved TLC method was performed. The assay according to Antunes et al. provided a reasonable quantification of HEPES using HPLC. Additionally, a reliable and conclusive TLC method was developed, which facilitates quantitative analysis by means of a pixel-based evaluation. A comparison of those two methods with the Ph. Eur. TLC assay pinpoints the superiority of the HPLC as well as the new TLC assay. Furthermore, evaluation of HEPES contents using both TLC assays by 28 subjects supported the conclusion that the newly developed TLC method is clearly favorable. The TLC method according to the Ph. Eur. provides unsatisfactory results in terms of conclusiveness and reproducibility. In contrast, a reported HPLC assay showed valid results, with the drawback of high technical effort. An optimized alternative is provided by the improved TLC method described in this work that results in reliable outcomes and additionally offers quantitative analysis.
Tài liệu tham khảo
Roesch F, Riss PJ. The renaissance of the 68Ge/68Ga radionuclide generator initiates new developments in 68Ga radiopharmaceutical chemistry. Curr Top Med Chem. 2010;10(16):1633–68.
Moerlein SM, Welch MJ. The chemistry of gallium and indium as related to radiopharmaceutical production. Int J Nucl Med Biol. 1981;8(4):277–87.
Weiner RE, Thakur ML. Chemistry of gallium and indium radiopharmaceuticals. In: Welch MJ, Redvanly CS, editors. Handbook of radiopharmaceuticals: radiochemistry and applications. New York: J. Wiley; 2003. p. 848.
Martins AF, Prata MIM, Rodrigues SPJ, Geraldes CFGC, Riss PJ, Amor-Coarasa A, et al. Spectroscopic, radiochemical, and theoretical studies of the Ga3+-N-2-hydroxyethyl piperazine-N’-2-ethanesulfonic acid (HEPES buffer) system: evidence for the formation of Ga3+ - HEPES complexes in (68)Ga labeling reactions. Contrast Media Mol Imaging. 2013;8(3):265–73.
Velikyan I. 68Ga-based radiopharmaceuticals: production and application relationship. Mol. 2015;20(7):12913–43.
Bauwens M, Chekol R, Vanbilloen H, Bormans G, Verbruggen A. Optimal buffer choice of the radiosynthesis of 68Ga–Dotatoc for clinical application. Nucl Med Commun. 2010;31(8):753–8.
Velikyan I, Beyer GJ, Långström B. Microwave-supported preparation of 68Ga bioconjugates with high specific radioactivity. Bioconjug Chem. 2004;15(3):554–60.
European Directorate for the Quality of Medicines (EDQM). European Pharmacopeia 7.7 (01/2013:2482 gallium (68Ga) edotreotide injection). Eur Pharm. 2011;23:310–3.
Meyer GJ, Mäcke H, Schuhmacher J, Knapp WH, Hofmann M. 68Ga-labelled DOTA-derivatised peptide ligands. Eur J Nucl Med Mol Imaging. 2004;31(8):1097–104.
Good NE, Winget GD, Winter W, Connolly TN, Izawa S, Singh RMM. Hydrogen ion buffers for biological research. Biochemistry. 1966;5(2):467–77.
Antunes I, Zijlma R, van der Woude G, Luurtsema G, Boersma H, Elsinga PH. A new fast and reliable HPLC method to detect HEPES in [68Ga]-radiopharmaceuticals. (meeting abstract) J Lab Comp Radiopharm. 2017;60(Suppl.1):293.
Kvaternik H, Barowitsch C, Hausberger D, Müller R, Aigner RM. Bestimmung von HEPES in Ga-68 markierten Peptiden mittels HPLC. (poster) Annual Meeting of the Austrian Society of Nuclear Medicine and Molecular Imaging, Zell am See; 2015.
Sasson R, Vaknin D, Bross A, Lavie E. Determination of HEPES in 68Ga-labeled peptide solutions. J Radioanal Nucl Chem. 2010;283(3):753–6.
Martin R, Jüttler S, Müller M, Wester HJ. Cationic eluate pretreatment for automated synthesis of [68Ga]CPCR4.2. Nucl Med Biol. 2014;41(1):84–9.
Schneider CA, Rasband WS, Eliceiri KW. NIH image to ImageJ: 25 years of image analysis. Nat Methods. 2012;9(7):671–5.
Schindelin J, Rueden CT, Hiner MC, Eliceiri KW. The ImageJ ecosystem: an open platform for biomedical image analysis. Mol Reprod Dev. 2015;82(7–8):518–29.
Merck AG. Anfärbereagenzien für Dünnschicht- und Papier-Chromatographie. http://phoenix.tuwien.ac.at/pdf/DC/DC_Farbreagent.pdf. Accesed 26 June 2018.