Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with [sup.99m]Tc

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with [sup.99m]Tc ([sup.99m]Tc-BLM and [sup.99m]Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with [sup.99m]Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of [sup.99m]Tc-BLM and [sup.99m]Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for [sup.99m]Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for [sup.99m]Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the [sup.99m]Tc-BLMG was found to be better than that of [sup.99m]Tc-BLM. Key words: biodistribution, BLM, BLMG, glucuronidation, radiolabeling, scintigraphy, [sup.99m]Tc