Preparation and biodistribution of 99Tcm-GHSA-IFNα2b

The work is to evaluate the liver-targeting ability of 99Tcm-GHSA-IFNα2b. 99Tcm-GHSA-IFNα2b was prepared by the reduction of Na99TcmO4 with SnCl2. Effects of the SnCl2 or GHSA-IFNα2b amount and pH value on the labeling yield of 99Tcm-GHSA-IFNα2b were investigated. The biodistribution was studied with ICR mice. 0.2 mL(0.286 MBq) 99Tcm-GHSA-IFNα2b solution containing 2 μg GHSA-IFNα2b was iv injected to each animal through the tail. The mice were decapitated at 5, 10, 15, 30, 60 and 120 min. The organs of interest were excised, weighed, and counted. The ID%/organ and ID%/g were calculated. Liver scan of 99Tcm-GHSA-IFNα2b was performed on a rat. The results showed that labeling yield of 99Tcm-GHSA-IFNα2b could be over 90% under the following labeling conditions: pH 3.0-4.5, over 0.3 mg of GHSA-IFNα2b, 3 μg-60 μg of SnCl2, and 30 rain labeling at 37 degree C. Biodistribution in mice showed a peak of liver uptake of 99Tcm-GHSA-IFNα2b in 10 min after injection, being excreted mainly via the biliary system and gastrointestinal tract. Clear liver images were obtained in 15-30 rain after injection. It can be concluded that GHSA-IFNα2b is a promising interferon with good liver-targeting ability, and 99Tcm-GHSA-IFNα2b is a potential hepatic receptor imaging agent. (authors)