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  • Author or Editor: P. Unak x
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Abstract  

The gas-chromatographic analysis of benzene-iodine solutions containing molecular iodine-125 after various storage times showed that no radiolytic products appeared while some products such as benzene, iodobenzene, biphenyl, and iodobiphenyl, were detected under the same analytical conditions in our recent studies concerning the reactions of iodine atoms activated by L shell photoelectric ionization in benzene-iodine solutions, and the self-radiolysis of iodobenzene labelled with iodine-12515. On the other hand, our theoretical calculations showed that if iodine molecules were uniformly distributed in benzene, iodobenzene should be detected as a radiolytic product due to the local absorption of Auger electrons of iodine-125. The absence of any radiolytic product clearly demonstrated that iodine aggregates have an important role in the absorption of Auger electrons of iodine-125 in benzene-iodine solutions. In addition, theoretical calculations showed that if the iodine aggregation is taken into account the experimental result agrees well with theoretical calculations.

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Abstract  

The radiolysis of iodobenzene labelled with125I has been investigated at liquid nitrogen and room temperatures, in the presence and absence of oxygen. After various storage times the samples were analyzed by gas chromatography, and benzene, vinyl iodide, biphenyl, and iodobiphenyl were detected. Biphenyl, benzene, and iodobiphenyl were found to be formed as a result of local radiolytic effect of Auger electrons of125I, and vinyl iodide was probably produced due to the decay effect of125I in labelled iodobenzene molecules. At the site of125I decay the Auger electrons are radiolytically effective within a spherical volume with diameter of about 30 . Outside this sphere the energy absorbed by iodobenzene molecules is not high enough to produce any radiolytical damage.

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Abstract  

Various methods were experimented to obtain complex of L-asparagine with99mTc. The VII state of Tc was reduced with direct reduction by SnCl2 and complex compound could not be obtained. For this reason, ligand exchange with99mTc-gluconate complex was tried and 20% yield was obtained.99mTc-pyrophosphate complex was carred out as second ligand exchanger and 50% yield was obtained in this experiment. Optimum conditions for ligand exchange with pyrophosphate are pH 11,50°C temperature, 60 minutes for reaction time and 278: 1 for pyrophosphate concentration to SnCl2 ratio.

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Abstract  

Labeling conditions of synkavit (2-methyl-1,4-naphthoquinol disodium phosphate) with iodine-125 have been studied. In this study, labeling temperature, reaction time, successive using of iodogen coated tubes, iodogen amount and synkavit concentrations have been determined to get optimum conditions for maximum labeling. Final results showed that when the labeling temperature, reaction time, synkavit concentration, and iodogen amount were, at room temperature, 15 min (in the case of successive using of three iodogen coated tubes), 2 mg ml–1 and 5 mg, respectively; labeling yield was 90% and specific activities of the order of 555 GBq mmol–1 (15 Ci mmol–1) have been obtained.

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Abstract  

Proton-ligand stability constants for some iodo and nitro derivatives of 8-hydroxyquinoline were determined by Calvin Bjerrum potantiometric method. The stability constants of the corresponding chelates with UO2 (II), Th(IV) and Co(III) were studied potentiometrically at 25 °C by applying Irving-Rossotti computing method. The complexes of the nitro-substituted ligands were less stable than the corresponding complexes of the unsubstituted ligands. The stability constants of metal-ligands depend on the ionic radii and ionic charge of metals and also they decrease with steric repulsions of the nitro groups.

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Abstract  

Complex forming conditions of 8-hydroxyquinoline with99mTc have been specified.99mTcO4 has been reduced by SnCl2 to a lower oxidation level. Labeling yields have been determined by ITLC (Instant Thin Layer Chromatography). Various parameters, such as pH, temperature, reaction time, ligand to SnCl2 ratio, which can affect the labeling yields, have been determined. Optimum conditions are 4–7 for pH; 15–20°C (room) for temperature; 1.55 for ligand to SnCl2 ratio and 5 min for reaction time.

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Abstract  

In this study, the stability constants of uranium(VI) and thorium(IV) complexes formed with 8-hydroxyquinoline (8-HOQ) and its 5-sulfonic acid (8-HOQ-5-SO3H) derivative have been determined using the Irving-Rossotti method, computing the Calvin-Bjerrum pH-titration data. As a result, it is determined that the thorium(IV) complexes are considerably more stable than the corresponding uranium(VI) complexes. On the other hand, the complexes formed between 8-HOQ-5-SO3H and uranium(VI) or thorium(IV) are less stable than the corresponding 8-HOQ complexes.

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Abstract  

8-Hydroxyquinoline (8-HOQ) is known as an important chelating agent for several metal ions. This compound is practically insoluble in water. For this reason, in this study its water soluble sulfate salt has been used for complexing uranyl ions and the stability constants of the complex have been determined. The Irving-Rosotti method computing the Calvin-Bjerrum pH-titration data, was applied. Finally, the stability constants of the complex formed between (8-HOQN-H)2SO4 and uranyl ions were found to be lgK1=8.25 and lgK2=4.15, the overall stability constant being {ie55-1}.

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Abstract  

Ornidazole (1-(3-chloro-2-hydroxypropyl)-2-methyl-5-nitroimidazole) was labeled with iodine-131 by using iodogen method. Quality controls were performed by instant thin layer chromatography (ITLC) and electrophoresis methods. Labeling yield was 91%. Iodination was carried out by substitution of chloride by iodine-131. Structure was confirmed by1H-NMR.

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Abstract  

Sertraline is an antidepressant drug. Sertraline was labeled with 131I by using iodogen method. Labeling yield was 85–90% and specific activity was approximately 64.75 GBq/mmol. The purification of radioiodinated Sertraline was performed by Sep Pak C-18 plus and the radiochemical purity was determined to be over 99%. Biodistribution studies were carried out by male Albino Wistar rats. The percentage of injected radioactivity per gram of tissue was calculated, and these data versus time curves were generated for organs and brain regions. The results showed that 131I labeled Sertraline may be a promising radiopharmaceutical for the investigation of serotonin 5-HT receptor functions of brain.

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