Optimization Methods for radiolabelling of DOTA-EB-cRGDfK with ^sup 111^In

• Published in: The Journal of nuclear medicine (1978) Vol. 59; p. 1833
• Main Authors: Lee, Shih-Ying, Lo, Sheng-Nan, Huang, Yuan-Ruei, Chen, Ming-Wei, Li, Ming-Hsin, Chang, Chih-Hsien
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.05.2018
• Subjects: Acetic acid; Angiogenesis; Breast cancer; Buffers; Cancer; Control methods; Energy research; Heating; High performance liquid chromatography; Invasiveness; Kinetics; Labeling; Liquid chromatography; Medical imaging; Metastases; Nuclear energy; Nuclear engineering; Nuclear reactors; Optimization; Pharmaceuticals; Precursors; Quality control; Radiochemical analysis; Radioisotopes; Radiolabelling; Reaction kinetics; Sodium; Sodium acetate; Thin layer chromatography
• ISSN: 0161-5505; 1535-5667

Objectives: The tripeptide Sequence RGD (Arg-Gly-Asp) has specific binding affinity of integrin αvβ3receptor. Integrin αvβ3 plays an important role in the regulation of tumor growth, angiogenesis, local invasiveness, and metastatic potential. Recent reports show that integrin αvβ3 expressed in many breast cancer specimens of breast cancer patients. To target integrin αvβ3receptor, EB-cRGDfK were link with DOTA and then labeled with 111In. The aim of this study was to find an optimization Methods of 111In labelling, and demonstrate 111In-DOTA-EB-cRGDfK has potential for diagnosis of breast cancer. Methods Quality control of DOTA-EB-cRGDfK precursor were >90% by High-performance liquid chromatography (HPLC). DOTA-EB-cRGDfK precursors were dissolved in DMSO. 111InCl3 was from Institute of Nuclear Energy Research, and were delivered in 0.01N HCl. The experiments were performed in 300μL volumes. We use 20~60μg of DOTA-EB-cRGDfK precursor in this labeling experiment. The reaction mixtures in different pH (1M Sodium acetate) were test. Heating were performed in a temperature-controlled heating system (Eppendorf, ThermoMixer C). The labeling yields of 111In-DOTA- EB-cRGDfK product were analyzed by radio-instant thin-layer chromatography (ITLC), and the radiochemical purities were analyzed by radio-HPLC. Results Kinetics of labelling of DOTA-EB-cRGDfK with 111In was optimal at pH6. When we use 30μg DOTA-EB-cRGDfK precursor, the labelling with 111In was completed after 10, min at 95℃.The labeling yields of 111In-DOTA- EB-cRGDfK were 97.1% in pH6.0 reaction buffer and 90.4% in pH4.5 reaction buffer. In the same condition, we use 20μg DOTA-EB-cRGDfK precursor, the labelling with 111In needs more time about 20 min at 95℃to achieve >90%.The labeling yields of 111In-DOTA- EB-cRGDfK were 96.1% in pH6.0 and 58.9% in pH4.5. At the same heating time about 15min at 95℃, we compare with different DOTA-EB-cRGDfK precursor usage amounts. The DOTA-EB-cRGDfK precursor we use in this experiment were 20, 25, 30, 40, 60μg, the labeling yields of 111In-DOTA- EB-cRGDfK were follow 81.3%,97.7%, 98.2% and 98.7% , 95.6%. Conclusions We demonstrate that 111In-DOTA-EB-cRGDfK has better labeling yields in pH6 than in pH4.5 (1M Sodium acetate). Optimization Methods of 111In-DOTA-EB-cRGDfK labelling, is use 30~40μg DOTA-EB-cRGDfK precursor , dissolved in pH6 (1M Sodium acetate) reaction mixture, heating at 95℃. Only need 15min, we can get the 111In-DOTA-EB-cRGDfK products with labeling yields and radiochemical purities >90%. 111In-DOTA-EB-cRGDfK has high specific activities and potential, can become a new radiopharmaceutical for breast cancer imaging.