Open AccessRadiolabeling efficiency and stability study on Lutetium-177 labeled bombesin peptide
Author(s) -
Boon-Uma Jowanaridhi,
Wiranee Sriwiang
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1380/1/012020
Subject(s) - bombesin , radionuclide therapy , peptide , chemistry , dota , in vivo , lutetium , radiochemistry , internalization , chelation , receptor , biochemistry , nuclear medicine , medicine , neuropeptide , microbiology and biotechnology , organic chemistry , yttrium , biology , oxide
Bombesin is a 14-amino-acid peptide having the ability to specifically bind gastrin releasing peptide receptors (GRPR) which show over-expression in many types of cancer cells. Therefore, bombesin analogs have been complexed with radionuclides and reported as radiopharmaceuticals for cancer diagnosis and therapy. Lutetium-177 (Lu-177) is a beta emitting radionuclide that decays with a half-life of 6.65 days. The medium beta energy and the relatively long half-life of Lu-177 make it one of the ideal radionuclides used in targeted radionuclide therapy. As the oxidation state of this radioisotope is 3+, it requires multidentate chelators such as DOTA to form stable complex. In this work, the commercially available conjugated peptide, DOTA-[Pro 1 , Tyr 4 ]-bombesin, was labeled with Lu-177 for preliminary formulation as a therapeutic radiopharmaceutical. The aim was to evaluate the radiolabeling efficiency using various amounts of the peptide and the stability in human serum for 7 days. The radiolabeling was performed in sterile water for injection with 5 mCi of Lu-177, adjusted to pH 5.5 to 6.0 by 0.5 M sodium acetate, and incubated at 100°C for 30 min. It was found that the radiochemical yield was more than 99% when using 20 µg of the peptide, and the complex was stable for a week. Moreover, human serum was used to simulate in vivo condition. The results showed high complex stability with more than 98% remaining intact after 7 days.