99mTc-Daunorubicin a potential brain imaging and theranostic agent: synthesis, quality control, characterization, biodistribution and scintigraphy

Daunorubicin is a chemotherapeutic antibiotic of the anthracycline family used for the treatment of many type of cancers when doxorubicin or other less effective drugs cannot be used. The aim of the present study was labeling of Daunorubicin with 99mTc, quality control, characterization, and biodistribution of radiolabeled Daunorubicin. Labeling efficiency was determined by ascending paper chromatography. All the experiments were performed at room temperature (25 °C ± 2 °C). More than 96% labeling efficiency with 99mTc was achieved at pH 5–6, 2–4 μg stannous chloride and 300 μg of ligand in few minutes. The characterization of the compound was performed by using HPLC, electrophoresis and shake flask assay. Electrophoresis indicates that Tc-99 m-Daunorubicin is neutral, HPLC confirms the single specie of the labeled compound, while shake flask assay confirms high lipophilicity. The biodistribution studies of 99mTc-Daunorubicin were performed in rats. Significantly higher accumulation of 99mTc-Daunorubicin was seen in brain of normal rats. Scintigraphy was also indicating higher accumulation of 99mTc-Daunorubicin in brain of normal rabbits.