Development and validation of the HPLC method for quality control of radiolabelled DOTA-TATE and DOTA-TOC preparations

Marcin Radzik; Justyna Pijarowska-Kruszyna; Antoni Jaroń; Michał Maurin; Clemens Decristoforo; Renata Mikołajczak; Piotr Garnuszek

doi:10.1016/j.nucmedbio.2020.11.005

Development and validation of the HPLC method for quality control of radiolabelled DOTA-TATE and DOTA-TOC preparations

Nucl Med Biol. 2021 Feb:93:63-73. doi: 10.1016/j.nucmedbio.2020.11.005. Epub 2020 Dec 3.

Authors

Marcin Radzik¹, Justyna Pijarowska-Kruszyna¹, Antoni Jaroń¹, Michał Maurin¹, Clemens Decristoforo², Renata Mikołajczak¹, Piotr Garnuszek³

Affiliations

¹ National Centre for Nuclear Research Radioisotope Centre POLATOM, 7 A. Soltana Street, 05-400 Otwock, Poland.
² Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020 Innsbruck, Austria.
³ National Centre for Nuclear Research Radioisotope Centre POLATOM, 7 A. Soltana Street, 05-400 Otwock, Poland. Electronic address: piotr.garnuszek@polatom.pl.

PMID: 33360498
DOI: 10.1016/j.nucmedbio.2020.11.005

Abstract

Introduction: The information on the presence of cold metal complexes in radiolabeled DOTA-TATE or DOTA-TOC is important in assessing the cause of the radiolabeling failure, poor radiolabeling yield and/or low effective molar activity. DOTA-peptide complexes are detectable using UV-Vis detector. The main limitation in the quantitative analysis is the limited availability of standard substances and the lack of data on their molar absorption coefficients. The aim of our study was development and validation of HPLC method enabling RCP analysis and identification and quantification of metal complexes impurities in the radiopharmaceutical preparations of DOTA-chelated peptides.

Methods: Complexes of DOTA-TATE and DOTA-TOC with several metals, were prepared. Their molar absorption coefficients at 220 nm were determined. The developed HPLC method has been validated in terms of quantitative determination of non-complexed DOTA-TATE and DOTA-TOC and their respective complexes with metallic individuals.

Results: Good chromatographic separation of the individual metal-DOTA-peptide complexes was achieved. The resolution between peaks of interest in radioactive preparations (complexes with: yttrium-90, lutetium-177, gallium-68) and metallic impurities was well above 1.5 (except gallium-68 DOTA-TOC preparations). Limits of detection and quantification were determined based on the parameters of the calibration curves. Based on the spectrophotometric and HPLC-DAD studies and statistical analysis of the results obtained, the average molar absorption coefficient was determined for studied DOTA-TATE and DOTA-TOC complexes, ε_HPLC-DAD = 48 × 10³M^-1 cm^-1. With the use of the determined molar absorption coefficient the method enabled quantitative determination of non-labelled peptide in the radioactive preparation in the linearity range of 0.5-100 μg/mL for DOTA-TATE(net) and 0.5-100 μg/mL for DOTA-TOC(net).

Conclusion: The developed HPLC method is suitable for RCP determination of radiolabelled DOTA-TATE and DOTA-TOC preparations. Determination of the average molar absorption coefficient for DOTA-TATE and DOTA-TOC complexes allows assessment of the total content of the peptide in radiopharmaceutical preparation regardless of its chemical form (free ligand, associated with radionuclide, in the form of a complex with metal ions being the impurity) using the HPLC method with UV detection.

Keywords: Complexes; DOTA-TATE; DOTA-TOC; HPLC; Impurities; Molar absorption coefficient; Radionuclides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Chromatography, High Pressure Liquid / methods*
Octreotide / analogs & derivatives*
Octreotide / chemistry
Positron-Emission Tomography*
Quality Control
Radionuclide Imaging*
Reproducibility of Results

Substances

copper dotatate CU-64
Octreotide
Edotreotide