Preparation and Radiochemical Evaluation of 99mTc-HYNIC-[Lys3,Tyr4] bombesin (3-14) for Prostate Cancer Detection

Background and Over-expression of GRP receptors for Bombesin has been reported to be found in malignant tissues, especially in prostate cancer. Here, we aimed at radiochemical and stability evaluation of a new bombesin derivative labeled with 99mTc via HYNIC as a chelating agent and Tricine/EDDA as coligands that might be used for diagnosis of prostate cancer.
In this experimental study (performed in 2016), the prepared bombesin was added to aqueous solution of Tricine/EDDA, then we added SnCl2, which was dissolved in HCl-containing solution. Finally the prepared bombesin was treated in 95 °C for 10 minutes. We investigated raiochemical purity using TLC and HPLC methods. Also, its stability in normal saline and human serum and percentage of protein-binding were studied.
Radiochemical purity was more than 98%. Stability in normal salin was 97.5, 96, and 95.5% after 1, 4, and 24 hours, respectively. Stability in human serum after 1 hour was more than 98% and after 4 hours was more than 92%. Percentage of protein-binding was 12.5, 14, and 16%, after 1, 4, and 24 hours, respectively.
This new bombesin derivative was easily labeled with 99mTc using exchange labeling and has some promising characteristics for prostate cancer detection.