Radiolabeling of gamma-irradiated rosmarinic acid by 67Gallium

Rosemary plant extract as a natural anti-oxidant is 4 times stronger than synthetic anti-oxidant like BHT and BHA. For this reason, it has been under attention not only for its anti-oxidant properties rather for its anti-inflammatory, anti-tumor, anti-bacterial, and anti-virus properties in different studies. This research investigates the effects of temperature, time, pH, and substance concentration in the labeling of irradiated rosmarinic acid by radioisotope gallium-67 as a high-resolution imaging agent for SPECT imaging. In this study, gamma irradiated rosmarinic acid nanoparticles at 20 kGy and 30 kGy levels in two concentrations of 0.5 and 1% were radiolabeled by gallium-67 radioisotope produced in Karaj cyclotron, and their efficiency and radiochemical purity were compared. Labeling conditions (including pH, temperature, time, and compound concentration) were investigated. Quality control was performed by thin-layer chromatography (RTLC). Resulting from the experiments, 30 kGy level and 1% concentration at 45 °C for 30 minutes at pH = 5.5-6 proved to be the best time for labeling rosemary nanoparticles, and the highest radiochemical purity achieved was 95%; radio conjugate also showed good stability after 12 hours.