Tumor uptake of radiolabeled pyrimidine bases and pyrimidine nucleosides in animal models —III. 2′-[ 82Br]-Bromo-2′-deoxyuridine

The tissue distribution and urinary excretion of i.v. doses of 2′-[ 82Br]-bromo-2′-deoxy-uridine (2′-[ 82Br]-UdR) have been studied in BDF 1 mice bearing subcutaneous Lewis Lung carcinomas. No tissue accumulated radioactivity to a greater concentration (cpmg −1) than whole blood, and elimination occurred primarily via the urine although some radioactivity was present in bile shortly after injection. Analysis of whole-body elimination data, and comparison of this data with that for i.v. doses of NH 4 82Br, showed that 55% of the radioactivity from a dose of 2′-[ 82Br]-UdR was eliminated in the form of the Br anion. Whole-body elimination of radioactivity from a single dose of 2′-[ 82Br]-UdR followed 2-compartment kinetics with half-lives of 3 and 30 h; NH Br elimination could be described as a single exponential function with a 30-h half-life.