Search Results
Summary
The organometallic precursor fac-[99mTc(CO)3(H2O)3]+ was reacted with N-ethoxy, N-ethyl dithiocarbamate (NOET) in phosphate buffered saline (pH 7.4) at room temperature for 30 minutes to produce the 99mTc(CO)3-NOET complex. The radiochemical purity (RCP) of the product was over 90% as measured by thin layer chromatography (TLC). No decomposition of the complex at room temperature (RT) was observed over a period of 6 hours. Its partition coefficient indicated that it was a lipophilic complex. The biodistribution comparison in mice of the 99mTc(CO)3-NOET complex and the 99mTcN-NOET complex showed that the former had a lower heart and brain uptake as compared to that of the latter, suggesting the incorporation of the [99mTc(CO)3]+ core into the NOET ligand does not improve the biological features as a myocardial imaging agent.
Abstract
The in vivo and in vitro stability of99mTc hydroxyethlylidene diphosphonate, 99mTc methylenediphosphonate and99mTc pyrophosphate in plasma has been studied using paper chromatographic technique as the analytical tool. The results indicate that the amounts of99mTc activity found both at the origin and Rf range of99mTcO4 − for in vivo experiments are slightly greater than those for either in vitro or control experiments. However, this amount of99mTc activity represents about 0.16–0.4% of the injected dose. Therefore, it is suggested that99mTc phosphorus radiopharmaceuticals are stable in vivo and neither oxidation nor hydrolysis of these bone imaging agents occurs in the blood.
Abstract
The effect of increased content of copper on the radiochemical composition of three skeletal imaging agents:99mTc(Sn)-methylene diphosphonate (MDP),99mTc(Sn)-pyrophosphate (PYP) and99mTc(Sn)-2,3-dicarboxypropane-1, 1-diphosphonate (DPD) was observed only in the case of99mTc(Sn)-MDP. It was found that the radiochemical purity of this radiopharmaceutical falls to about 50% when the copper content reaches about 10–5 mol dm–3. According to the results of radiochemical and biological analyses, it could be concluded that with the increase of copper content, the content of free pertechnetate rises, too. The two other radiopharmaceuticals,99mTc(Sn)-PYP and99mTc(Sn)-DPD, were found to be stable under the given experimental conditions.
Abstract
The radiochemical purity of the three osteopatic ligands:99mTc(Sn)-PyP,99mTc(Sn)-DPD and99mTc(Sn)-MDP has been determined by gel chromatography on Sephadex. The results of the analyses strongly depend on the composition of the eluent. The dilution effect of pure saline as eluent was observed in all the preparations examined. The most sensitive was found to be99mTc(Sn)-PyP. The retention of99mTc activity bound to the gel matrix (99mTc-hydrolyte) was over 30%. The diphosphonates were found to be more stable (retention 10–15%). The retention is substantially lower, i.e. a high recovery of the labeled complexes is obtained when the eluent contains the ligand. The best results are obtained when the eluent contains the same concentrations of ligand and reductant as in the labeled complex. There was no significant difference in the behavior of the given radiopharmaceuticals prepared as a fresh solution and in the freeze-dried kit.
Abstract
A procedure for obtaining a stable99mTc(V)-DMSA kit and methods for its radiochemical and biological control are described. The effect of pH on radiopharmaceutical stability of the complex was studied. The kinetic parameters of99mTc(V)-DMSA were determined on rats and compared to the corresponding values for renal99mTC-DMSA. Clinical tests showed that99mTc(V)-DMSA is suitable agent for detecting the primary medullar carcinoma of thyroid, as well as for detection of thyroid metastasis.
Abstract
The results obtained for radiochemical purity of ITLC (SA) and (SG) using different solvent systems and low voltage electrophoresis are presented in the paper. Radiochemical purities obtained for99mTc-dimethyl IDA (99mTc-HIDA) and99mTc-diethyl IDA (99mTc-EHIDA) are 98.1±0.6% and 98.7±0.5%, respectively. Variable99mTc hydrolyzate contents, depending on the ionic strength of the eluents and on the time interval between labelling and analysis, have been obtained by Sephadex chromatography. The eluent containing Sn-EHIDA inhibits dissociation of99mTc-EHIDA due to dilution of the preparation during elution of the column and yielding only a small percent of Sephadex bound fraction, as compared to other investigated eluents. The range of normal99mTc-IDA biodistribution values in the organs of experimental animals and statistical significance of the difference between these two preparations have also been determined. The results obtained for99mTc-HIDA and99mTc-EHIDA in the liver are 33.9±5% and 25.7±4.7%, respectively p<0.01.
Abstract
Methods for the preparation and analysis of a new renal radiopharmaceutical,99mTc-thiodiglycolic acid (TDGA), are reported. The kit for Tc-TDGA contains a lypophilized acidic (pH 2.5) mixture of 5 mg TDGA and 0.05 mg SnCl2·2H2O. Acetate buffer has been found to be a suitable solvent for paper chromatography of99mTc-TDGA. The results of the quantitative organ distribution studies in rats and rabbits indicated the characteristics of99mTc-TDGA to be intermediate to the renal tubular agent131I-Hippuran and the GFR agent99mTc-DTPA.
Abstract
A method for preparing99mTc-citrate complex, using instantly formed cuprous ions for the reduction of pertechnetate is described. The labelling kinetics, formation rate and stability of99mTc-Cu-citrate complex were studied. Gel filtration using column scanning technique has been found to be a reliable and unique tool for determining the amount of99mTc-fractions as a function of time in the preparation. The kidney uptake and excretion characteristics suggest a potential usefulness of99mTc-Cu-citrate complex for renal function studies. The safety measures for the amount of the complex to be injected in man have been estimated.
Abstract
Kits were developed-for the sterile labelling of phytate with99mTc. The effect of molar ratio of phytate to stannous chloride, pH, dilution of the Sn-phytate with99mTc-generator eluate, time of incubation, the shelf life of99mTc-phytate and the storage time of Sn-phytate on the labelling yield of phytate with99mTc was investigated using paper chromatography and gel chromatography column scanning method (GCS). Organ distribution was performed in rabbits and mice. Excellent human liver scans were obtained.
Abstract
The application of K3W2Cl9 as reducing agent in preparation of99mTc-labelled compounds is described. Pertechnetate reduction was carried out in solutions of pH 
2 and also of pH 5.5. DTPA, citrate, gluconate, HEDSPA and MDP were successfully labelled. Two types of labelled gluconate complexes were obtained. Complex I exhibited in rats an increased99mTc affinity to kidneys (21%). Complex II exhibited an increased99mTc affinity to bone (8.7%). Two types of labelled HEDSPA preparations were obtained: one yielded 29%99mTc activity in bone, the other type exhibited only 13.4%. The results indicated the absence of mixed complexes.
