Dynamic Distribution of 67Ga-Bleomycin Complex and Carrier Free 67Gallium in Normal Mice

This study reports the labeling of Gallium-Bleomycin (67Ga-BLM) complex as a radiopharmaceutical and optimization of its labeling conditions; pH, reaction time, temperature, concentration of bleomycin and its biodistribution in normal Bulb C mice. The biodistribution of the complex was compared with 67Ga-Cl3 in 11 selected organs including blood, liver, lung, spleen, muscle, skin, heart, kidney, colon, colon content, and bladder at five selected times of 1, 2, 4, 24 and 48 hours after injection. Cyclotron produced 67Gallium was labeled with bleomycin under Thakur method. The optimized pH condition was found 2 at temperature of 90ºC for reaction temperature of 30 minutes when 0.5 mg of bleomycin was mixed with 1 mCi of 67Ga-Cl3. Pharmacokinetic data indicated higher uptakes of 67Ga-BLM in all 11 tissues except blood, liver and spleen in comparison with 67Ga-Cl3. The average of total uptakes from 67Ga-BLM and 67Ga-Cl3 radiopharmaceuticals at one hour after injection were 73.35% and 53.55% then reduced to 14.55% and 25.2% after 48 hours respectively. The blood uptake of 67Ga-Cl3 was higher than 67Ga-BLM in all time intervals. Bladder uptake of 67Ga-BLM was highest among 11 tissues at all time intervals but the uptake of 67Ga-Cl3 was only highest at first hour after the injection. The results indicated the high stability of the complex both in-vitro and in-vivo, and yet excreted faster than carrier free 67Gallium. The effective half life of 67Ga-BLM complex was found 48.15 hours.