Search Results
Abstract
The kinetics of99mTc-d, 1-HMPAO decomposition is studied using home kits. The results showed that99mTc-d, 1-HMPAO decomposition is a first-order reaction. The decomposition constant k is found to be 0.017±0.007h–1 under the experimental conditions of 20°C, 185MBq/ml, pH 7.0. The stability of99mTc-d, 1-HMPAO is affected not only by pH and radioactive concentration, but also by temperature. Using Immol/l gentisic acid as a stabilizer, 740MBq/ml of99mTc-d, 1-HMPAO can be stabilized for 3h with the radiochemical purity above 80%.
Abstract
Ligand exchange is one of the possible synthetic routes to obtain99mTc coordination compounds. However, the success of this route depends on the availability of good precursors. The objective of this work is the preparation of the complex [99mTc(tu)6]3+ (tu = thiourea), as a potential precursor for99mTc(III) coordination compounds. The preparation was successfully performed in acidic conditions, the excess of tu serving as reducing agent. At pH values higher than 3, the compound becomes unstable and on addition of polydentate ligands new Tc(III) complexes are formed. With edta, the complex99mTc(III)-edta was obtained in high yield.
Abstract
One novel styrylpyridine derivatives(AV-45) coupled with 99mTc complex was synthesized. 99mTc-BAT-AV-45 was prepared by a ligand exchange reaction employing sodium glucoheptonate, and effects of the amount of ligand, stannous chloride, sodium glucoheptonate and pH value of reaction mixture on the radiolabeling yield were studied in details. Quality control was performed by thin layer chromatography and high performance liquid chromatography. Besides the stability, partition coefficient and electrophoresis of 99mTc-BAT-AV-45 were also investigated. The results showed that the average radiolabeling yield was (95 ± 1%) and 99mTc-BAT-AV-45 with suitable lipophilicity was stable and uncharged at physiological pH.
Abstract
The preparation of99mTc-Sn-EBV and99mTC-Sn-EBA is described. Different parameters affecting the labeling efficiency (ligand concentration, pH, molar ligand: reducing agent ratio) as well as the time-dependent stability of labeled compounds were investigated. Preliminary biodistribution studies in Wistar rats showed accumulation of the above mentioned compounds in kidneys.
Abstract
Carrier-free99mTcO4 – eluated from clinical99Mo/99mTc generators was examined to determine its specific activity. The observed specific activity was found to be always lower than the calculated value based on the99Mo–99mTc–99Tc decay scheme data. These results could be explained in terms of existence of excess Tc loaded onto generator column.
Abstract
A procedure for preparation of a sterile closed system generator for99mTc based on conversion to zirconium molybdate of99Mo produced by neutron activation is reported. The generator is sterilized by autoclaving.99mTc is eluted using 0.9% NaCl with high yield and purity in successive elutions.
Abstract
99mTc-dimercaptosuccinic acid is one of the most widely applied radiopharmaceutical for renal scintigraphy. This complex was prepared by ligand exchange reaction from99mTc-gluconate at tracer concentration of technetium under acidic conditions. The exchange yield was determined by paper chromatography and reaction rate constants were calculated at different pH values.
Abstract
The in vitro stability of99mTc (Sn)-PyP as a function of experimental conditions of the preparation of the kit and time elapsed after labeling has been tested. The preparation was protected by using nitrogen-purged reactant solutions and kit vials and by ascorbic acid. The samples under nitrogen are stable for 6 h when the content of99mTc-pertechnetate raises to 5%. The best stability was achieved by addition of 5 
g of ascorbic acid per ml of the kit (content of99mTc-pertechnetate about 0.5%). To accelerate the decomposition, exogenous hydrogen peroxide was used. In this case it was found that the presence of 10 g of ascorbic acid inhibits the effect both of oxygen and peroxide (6 g H2O2/ml of the kit). Radiochemical purity of99mTc (Sn)-PyP remains practically unchanged for 6 h (content of99mTc-pertechnetate about 0.5%).
Abstract
This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of the 99mTc(CO)3–AOPA colchicine conjugate. The novel ligand was successfully synthesized by conjugation of N-(acetyloxy)-2-picolylamino (AOPA) to deacetylcolchicine via a short carbonyl-methylene linker. Radiolabeling was performed in high yield with [99mTc(CO)3]+ core. 99mTc(CO)3–AOPA colchicine conjugate was hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that 99mTc(CO)3–AOPA colchicine conjugate accumulated in the tumor with good uptake and retention. However, its clearance from normal organs was not so fast, resulting in poor T/NT ratios. Further modification on the linker or/and 99mTc-chelate to improve the tumor targeting efficacy and in vivo kinetic profiles is currently in progress.
Abstract
The aim of this study is to examine biological behaviour of radiolabeled guanine with [Tc(CO)3]+ core in vitro and in vivo. In vitro biological behavior of 99mTc(CO)3–Gua was evaluated on Lung (A-549), Breast (MCF-7), Colonic (Caco) carcinoma cell lines and normal human bronchial epithelial (NHBE). 99mTc(CO)3–Gua compound showed high uptake on A-549 cell line when compared to NHBE cell line. Biodistribution characteristics of 99mTc(CO)3–Gua was evaluated using New Zeland Rabbits. Scintigraphic results showed that a high level of radioactivity was observed in the lungs and liver shortly after administration of the 99mTc(CO)3–Gua and excretion takes place via both renal and hepatobiliary route. It was concluded that 99mTc(CO)3–Gua could be used as a nucleotide radiopharmaceutical for imaging purposes.
