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    Complexation Behavior of Guanine with Th4+, UO22+, and Ce3+ at Various Temperatures
    (Amer Chemical Soc, 2010) Teksoz, Serap; Ichedef, Cigdem Acar; Unak, Perihan
    The complexation of guanine with Th4+, UO22+, and Ce3+ was investigated using the potentiometric method at a constant ionic strength of I = 0.10 mol.dm(-3) (KCl) in aqueous solutions at elevated temperatures. For each metal ion, stability constants were obtained from the pH-metric data using the program HYPERQUAD2006. The formation of monomeric and polymeric species was taken into consideration for each ion at (25, 37, and 45) degrees C. The thermodynamic parameters for the formation of the guanine complexes were calculated. In conclusion, it is indicated that the values of the stability constants change at various temperatures.
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    Diethylstilbestrol glucuronide (DESG): synthesis, labeling with radioiodine and in vivo/in vitro evaluations
    (Springer, 2013) Yilmaz, Tayfun; Unak, Perihan; Muftuler, Fazilet Zumrut Biber; Medine, Emin Ilker; Sakarya, Serhan; Ichedef, Cigdem Acar; Unak, Turan
    Diethylstilbestrol (DES) is a synthetic non-steroidal estrogen, pharmacologic effects of which resemble natural estrons; today it is being used to treat some types of postmenopausal breast cancer and advanced prostate cancer. The aim of current study is conjugation of glucuronic acid (G) to DES and to evaluate radiopharmaceutical potential of this estrogen glucuronide derivative (DESG) which is specific to beta glucuronidase enzyme consisting tumor cells. Taking into consideration the compatibility to the chemical structures of the synthesized product, I-131 and I-125 were chosen as the appropriate radionuclides and DESG was labeled with these radionuclides utilizing iodogen method. The radiochemical yields of I-125/131-DESG were over 90 % according to thin layer radio chromatography method. The biodistribution of I-131-DESG in healthy female Wistar Albino rats has been investigated and the range of the breast/blood and breast/muscle ratios were approximately 2 and 13 in 240 min for ER unsaturated studies. Effects of the radioiodinated DES and DESG on the cells were examined using MCF-7, A-549, Caco-2 cell lines. I-125-DESG has higher incorporation percentages than I-125-DES on MCF-7 cells. The radioiodinated DESG has the desired radiopharmaceutical properties which could be candidate radiopharmaceuticals for diagnosis and especially radionuclide therapy of breast tumors.
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    Diethylstilbestrol glucuronide (DESG): synthesis, labeling with radioiodine and in vivo/in vitro evaluations
    (Springer, 2013) Yilmaz, Tayfun; Unak, Perihan; Muftuler, Fazilet Zumrut Biber; Medine, Emin Ilker; Sakarya, Serhan; Ichedef, Cigdem Acar; Unak, Turan
    Diethylstilbestrol (DES) is a synthetic non-steroidal estrogen, pharmacologic effects of which resemble natural estrons; today it is being used to treat some types of postmenopausal breast cancer and advanced prostate cancer. The aim of current study is conjugation of glucuronic acid (G) to DES and to evaluate radiopharmaceutical potential of this estrogen glucuronide derivative (DESG) which is specific to beta glucuronidase enzyme consisting tumor cells. Taking into consideration the compatibility to the chemical structures of the synthesized product, I-131 and I-125 were chosen as the appropriate radionuclides and DESG was labeled with these radionuclides utilizing iodogen method. The radiochemical yields of I-125/131-DESG were over 90 % according to thin layer radio chromatography method. The biodistribution of I-131-DESG in healthy female Wistar Albino rats has been investigated and the range of the breast/blood and breast/muscle ratios were approximately 2 and 13 in 240 min for ER unsaturated studies. Effects of the radioiodinated DES and DESG on the cells were examined using MCF-7, A-549, Caco-2 cell lines. I-125-DESG has higher incorporation percentages than I-125-DES on MCF-7 cells. The radioiodinated DESG has the desired radiopharmaceutical properties which could be candidate radiopharmaceuticals for diagnosis and especially radionuclide therapy of breast tumors.
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    Tc-99m-D-Penicillamine-Glucuronide: Synthesis, Radiolabeling, In Vitro and In Vivo Evaluation
    (Mary Ann Liebert Inc, 2011) Teksoz, Serap; Ichedef, Cigdem Acar; Ozyuncu, Seniha; Muftuler, Fazilet Zumrut Biber; Unak, Perihan; Medine, Ilker Emin; Ertay, Turkan; Eren, Mine Sencan
    The current study was aimed at synthesizing a glucuronide derivative of D-penicillamine (D-PA) to be used for imaging purposes. First of all, D-PA-glucuronide (D-PA-Glu) was synthesized by experimental treatments starting with uridine 5'-diphospho-glucuronosyltransferase enzyme rich microsome preparate. Then, the synthesized compound was labeled with technetium (Tc-99m) by using a reduction method with stannous chloride. Quality controls were performed by using high-performance liquid chromatography and thin-layer radio chromatography (TLRC). Radiolabeling yield of Tc-99m-D-PA-Glu was more than 98% according to TLRC results. In vitro evaluations of radiolabeled complexes were investigated on PC-3 human prostate cancer cells. Tc-99m-D-PA-Glu exhibited more accumulation on PC-3 cells versus Tc-99m-D-PA at 240 minutes. In order to determine its radiopharmaceutical potential, biodistribution studies were carried out in male Albino Wistar rats. The biodistribution results of Tc-99m-D-PA-Glu, showed the highest uptake in prostate at 120 minutes postinjection with the main excretion route being through kidneys and bladder. Tc-99m-D-PA-Glu and Tc-99m-D-PA have exhibited different biodistribution results.