A new 111In-bleomycin complex for tumor imaging: preparation, stability, and distribution in glioma-bearing mice

A new 111In-bleomycin complex (111In-BLMC) is here reported. Its radiochemical purity was 99% by thin-layer chromatography (TLC) (Rf 0.65) and in 5% agarose gel electrophoresis in 0.02 M NaHCO3 it migrated toward the anode. Autoradiographs of TLC and gel electrophoresis plates showed no change on storage for 3 weeks. Urine and plasma from untreated or glioma-bearing mice after injection of 111In-BLMC were analyzed by TLC and gel electrophoresis. Results indicated stability in vivo, nonbinding to transferrin, affinity to viable tumor, and excretion faster than 111In-BLM-B2, 111In-BLM, or 57Co-BLM. Tissue distributions 24 hr after injection of radiopharmaceutical showed activity ratios of tumor to blood, muscle, and brain of 13.1, 12.4, and 81.6, respectively, which were significantly higher than those for previously prepared 111In-BLM-B2 or 111In-BLM (except for brain, 0.05 less than P less than 0.1). The new 111In-BLM complex may be useful in clinical imaging and for combining radionuclide radiotherapy and chemotherapy.