From octreotide to shorter analogues: synthesis, radiolabeling, stabilityстатья
Информация о цитировании статьи получена из
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Дата последнего поиска статьи во внешних источниках: 4 марта 2022 г.
Аннотация:This study aims at analyzing complexation properties of two new short somatostatin analogues, their synthesis, radiolabeling with 44Sc, 207Bi and 152Eu, and stability in vitro. Short tetrapeptide Phe-D-Trp-Lys-Thr and pentapeptide Thz-Phe-D-Trp-Lys-Thr were first conjugated with the DOTA macrocyclic chelator. These conjugates were radiolabeled with 44Sc, 207Bi and 152Eu and characterized by TLC and HPLC. The radiochemical purity was measured using digital autoradiography and gamma-spectrometry. Optimum conditions of DOTA-conjugate labeling were found: 0.1 mM, pH 8.0-8.4 at 90°C for DOTA-tetrapeptide complexes with 207Bi and 152Eu; 0.05 mM, pH 4.0-5.0 at 90°C for 44Sc-DOTA-tetrapeptide; 0.2 mM, pH 4.0-5.0 at 90°C for 44Sc-DOTA-pentapeptide. Complexes of DOTA-pentapeptide with 207Bi and 152Eu of radiochemical purity ˃ 95% were probably unstable at temperature higher than 37°C and were obtained at 37°C, pH 8.0-8.4 within 4 days. Mass-spectra of the Eu-DOTA-pentapeptide revealed the presence of small fragments of the pentapeptide conjugate in the complex solution. In vitro stability studies were performed in saline in the presence of serum proteins and biologically relevant metal cations. All complexes demonstrated no cation release in vitro within 1–4 hours.