Extraction, radiolabeling, and biodistribution of thebaine in rats

The goal of this study was to determine the radiopharmaceutical potential of radioiodinated thebaine. Thebaine was extracted from dry capsules of opium poppy (Papaver somniferum L.), purified using high-performance liquid chromatography, and characterized with nuclear magnetic resonance and infrared spectroscopy. The purified thebaine was labeled with I-131 using the iodogen method. Normal and receptor-blockage biodistribution studies were performed in male Albino Wistar rats. The results of the tissue distribution studies showed that the uptake of I-131-thebaine in the stomach, large intestine, spinal cord, and prostate was higher than in the other tissues. A greater uptake of radiolabeled thebaine in the rat brain was observed in the midbrain and hypothalamus. We concluded that (1) the labeling yield of I-131-thebaine was high, (2) a large amount of I-131-thebaine remained in the midbrain and hypothalamus, and (3) I-131-thebaine had enough stability for diagnostic scanning.