Purpose of the study: Ga-68-DOTA-peptides targeting somatostatin receptors have been assessed as a valuable tool in neuroendocrine tumors imaging using positron emission tomography (PET). A new selective and sensitive high-pressure liquid chromatography (HPLC) method was developed for determining chemical and radiochemical purity of Ga-68-DOTATATE (PET) tracer. The identification of peaks was achieved on a symmetry C18 column 3 μm 120Å (3.0 mm × 150 mm spherical particles) using (A) water + 0.1% trifluoroacetic acid (TFA) and (B) acetonitrile + 0.1% TFA, as the mobile phases at a flow rate of 0.600 mL/min and monitored at 220 nm. The run time was 16 min.
Materials and methods: The method was validated to fulfill International Conference on Harmonization requirements and EDQM guidelines, and it included specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision.
Results: The calibration curve was linear over the concentration range from 0.5 to 3 μg/ml, with a correlation coefficient (r2) equal to 0.999, average coefficient of variation (CV%) 2%, and average bias% did not deviate more than 5% for all concentrations. The LOD and LOQ for DOTATATE were 0.5 and 0.1 μg/mL, respectively. The method was considered precise, obtaining coefficients of variation between 0.22% and 0.52% for intraday and 0.20% and 0.61% for interday precision. Accuracy of method was confirmed with average bias% that did not deviate more than 5% for all concentrations.
Conclusion: All results were acceptable and this confirmed that the method is suitable for its intended use in routine quality control of Ga-68-DOTATATE to guarantee the high quality of the finished product before release.
Keywords: Ga-68-DOTATATE; positron emission tomography imaging; somatostatin receptors; validation of HPLC method.
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