F. Yurt Lambrecht

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 131I 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 131I-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 131I-thebaine was high, (2) a large amount of 131I-thebaine remained in the midbrain and hypothalamus, and (3) 131I-thebaine had enough stability for diagnostic scanning.

Synthesis of a 99mTc labeled estrogen-derivative and the determination of its radiopharmaceutical potential on rats

An estrogen derivative 1-(3, 17-α-estradiolyl propin-1-yl-3-(1,4,8,11-tetraazacyclotetradecyl)-propanate (ESTACPA) was synthesized. The product was purified by HPLC and characterized by NMR and IR spectroscopy. The synthesized compound was labeled with 99mTc. The biodistribution studies were performed on female Albino Wistar rats. The rats were sacrificed and their organs were removed. The radioactivities of the organs were counted using a gamma-counter. The activity per gram tissue was calculated and time versus activity curves were generated. The 99mTc-ESTACPA uptake by the uterus and ovary such as ER-rich tissues, were observed. The pancreas and stomach also showed a significant uptake.

Biodistribution of 99m technetium- labeled creatinine in healthy rats

The distribution of creatinine, one of the toxic guanidine compounds, in various tissues has not been studied in detail by using radiolabeled creatinine. Our objective was to investigate the biodistribution of creatinine labeled with 99m technetium (99mTc) by the stannous (II) chloride method in healthy male Wistar rats. Quality controls were carried out by radio thin layer chromatography, high-performance liquid chromatography, and paper electrophoresis. The labeling yield was 85 +/- 2% under optimum conditions (pH 7 and 100 microg stannous chloride). Rats (N = 12) were injected intravenously with 99mTc-creatinine and their blood and visceral organs were evaluated for 99mTc-creatinine uptake as percent of the injected dose per gram wet weight of each tissue (%ID/g). The lowest amount of uptake was detected in the brain and testis. When the rate of uptake was evaluated, only the kidney showed increasing rates of uptake of 99mTc-creatinine throughout the study. Kidneys showed the highest amount of uptake throughout the study (P < 0.001 compared to all other organs), followed by liver, spleen and lung tissue.