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EN
Chitosan was chemically modified by diethylenetetraaminepentaacetic acid (DTPA) in different degrees of modification (DM = 6.1, 10.3, 15.7 and 20.9%). DTPA-chitosans were radiolabeled with gallium-66 radionuclide. The effect of several factors on labeling yield such as degree of modification, acidity and concentration of DTPA-chitosan solution, contact time and radioactivity was investigated. Radiolabeled DTPA chitosans were intratumorally injected to fibrosarcoma bearing mice and the leakage of radioactivity from the injection site was evaluated. In comparison with chitosan, all DTPA chitosans showed better efficiency in preventing the leakage of radioactivity from tumor lesion and DTPA-chitosan (DM = 10.3%) was the best which led to remaining 97% of injected dose in the injection site after 54 h of injection. The highest leaked radioactivity from the injection site was in the lungs, liver, spleen and the kidneys. Our results indicated that the DTPA modified chitosan can be an effective carrier for therapeutic radionuclides for tumor treatment by the intratumoral injection technique.
EN
[66Ga]gallium chitosan complex was prepared with a high radiochemical purity (greater than 99%) in dilute acetic acid solution. The radiochemical purity of [66Ga]gallium chitosan complex was checked by using paper chromatography technique. The prepared complex solution was injected intratumoral to fibrosarcoma-bearing mice and the leakage of radioactivity from injection site was investigated. Approximately, 85.4% of the injected dose was retained in the injection site 54 h after injection and most of the leaked radioactivity was accumulated in the blood, liver (0.5%) and lung (6.5%).
EN
[61Cu]bleomycin ([61Cu]BLM) was prepared using [61Cu]CuCl2 produced via natZn(p,x)61Cu. [61Cu]BLM was prepared under optimized conditions (room temperature, 45 min, 0.1 mg bleomycin for 92.5–370 MBq 61CuCl2) with radiochemical purity over 98% shown by HPLC and RTLC. [61Cu]BLM was administered into normal and tumor bearing rodents up to 210 min followed by biodistribution and co-incidence imaging studies. A significant tumor/non tumor accumulation was observed either by animal sacrification or an imaging method. [61Cu]BLM can be a potential PET radiotracer for tumor imaging.
EN
Human gamma globulin can be labeled by a direct or indirect method of radiotracer incorporated in a protein molecule. In this indirect method hydrazinonicotinic acid (HYNIC) is used which saves the structure and biological activity of the protein. Our goal was the efficient labeling of the human gamma globulin and evaluation of its biodistribution in different organs which can be used on experimentally induced infection causing inflammation. Immune globulin is mixed with s-hynic and IgG-hynic is developed using sidle A-lyzer and stored at –20°C which can be used at least for six months and then Sn-tricine kit is prepared which is used for 99mTc labeling. Efficiency of 99mTc-IgG-hynic labeling at pH 6.4 was very much dependent on ligand (hynic) and coligand (tricine) presence in the reaction mixture. Radiochemical purity was more than 90% in the kits prepared. Serum stability study showed no decomposition of 99mTc from the complex. The biodistribution studies showed the highest percentage ID/organ in the blood, liver and kidney, respectively. A human gamma globulin was successfully labeled through hynic to 99mTc by an indirect method with high radiochemical purity.
EN
Due to interesting role of dihydropyridines in cardiovascular diseases and drug resistance studies and lack of a fluorine-18 labeled imaging agent for L-type calcium channel studies, this study was designed. [18F]Dimethyl 2-(fluoromethyl)-6-methyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate 2 was prepared in no-carrier-added (n.c.a.) form from a starting brominated compound in one step at 80°C in Kryptofix2.2.2/[18F]. Compound 2 was administered to normal rats via their tail veins for preliminary biodistribution studies and the ID/g% of the labeled compound was determined up to 3 h post injections. Coincidence images were obtained in rats 5 to 120 min. Radiofluorination on bromo precursor gave a fluorinated compound in 95% radiochemical purity and a 8% yield shown by RTLC and HPLC. Biodistribution studies showed that the tracer is accumulated in the heart in the first few minutes, followed by metabolism resulting in very soluble 18F-containing metabolites eliminated through the urinary tract. In coincidence images, the target organ was shown to be the heart. Lung had high accumulation possibly due to the presence of Ca2+ channels and/or hydrolyzing enzymes showing a significant myocardial uptake at 120 min. The data demonstrates a significant agreement with the reported L-type calcium channels throughout the animal body. To our knowledge, this is the first example of 18F-DHPs in the literature.
EN
Human recombinant insulin was successively labeled with [67Ga]-gallium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation were obtained by the addition of 0.5 ml of an insulin pharmaceutical solution (5 mg/ml, in phosphate buffer, pH = 8) to a glass tube precoated with DTPA-dianhydride (0.01 mg) at 25°C with continuous mild stirring for 30 min. Radiothin-layer chromatography (RTLC), instant thin-layer chromatography (ITLC) and high-performance liquid chromatography (HPLC) showed overall radiochemical purity higher than 96% in optimized conditions (specific activity = 300 500 MBq/mg, labeling efficiency 77%). Preliminary in vivo studies with normal rats were performed to determine the biodistribution of the radiotracer up to 110 h. They showed a high liver uptake of the tracer which is consistent with other reported radiolabeled insulins.
EN
Human polyclonal antibody (HIgG) was successively labeled with 111In-indium chloride after residulation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of solid DTPA-dianhydride (0.1 0.3 mg) to 100 mi l of the HIgG solution (0.2 0.4 mg/ml) at pH = 6 in phosphate buffer media at 25°C with continuous stirring for 30 min. Radio-thin-layer chromatography showed an overall radiochemical yield of 96 99% at optimized conditions (specific activity = 300 500 MBq/mg, radiochemical purity >98%). The final isotonic 111In-DTPA-HIgG complex was checked by radio-TLC to ensure the formation of only one species followed by filtration through a 0.22 mi filter. Preliminary long-term in vivo studies in turpentine-oil induced inflammation in rat model was performed to determine late complex distribution of the radioimmunoconjugate. The target/skin and target/ blood ratios were 27 and 51 after 24 h, and 23 and 51 after 110 h, showing a high selectivity of the radiopharmaceutical for inflammatory lesions.
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