Search Results
Abstract
Two methods for the determination of radiochemical purity of preparations labeled with99mTc are described. Paper chromatography was used for separation of reduced99mTc and free pertechnetate from the labeled radiopharmaceutical. Whatman 3MM paper was used first with a acetone and then with 1N NaCl, as the mobile phase. Instant thin layer chromatography was performed for comparison. The electrophoretic method was also applied, using 0.05 M Na-acetate and 0.017 M NaCl. Biodistribution of99mTc-DMSA in the organs of experimental animals was followed in order to verify chemical control methods.
Abstract
Physico-chemical characterization of99mTc-radiopharmaceuticals is presented. Limiting pH values, iso-osmotic pressure and the apparent coefficient values between two immiscible phases are determined too. A selection of radiochromatographic methods /stationary or mobile phase/ for routine quality control of99mTc radiopharmaceuticals for radiochemical purity was made. The methods chosen are simple, accurate, sufficiently sensitive and fast in operation. The mean values were determined for99mTc radiopharmaceutical distribution per organs, characteristic for the tested preparates and for radiochemical purity, as well as the time interval from injection to sacrifice of the animals.
Summary
Kanamycin is an antibiotic used for treatment of infections when penicillin or other less toxic drugs cannot be used. Kanamycin was labeled with technetium-99m pertechnetate using SnCl2 . 2H2O as reducing agent. The labeling efficiency depends on the ligand/reductant ratio, pH, and volume of reaction mixture. Radiochemical purity and stability of 99mTc-Kanamycin was determined by thin layer chromatography. Biodistribution studies of 99mTc-Kanamycin were performed in rats and rabbits. A significantly higher accumulation of 99mTc-Kanamycin was seen at sites of S. aureusinfected animals (rat/rabbit).
Abstract
Four stereoisomeric99mTc complexes from meso and racemic 2,3-dimercaptosuccinic acids /DMSA/ were prepared controlling the pH and the molar ratio of ligand to tin/II/ chloride. The complexes showed different thermal stability and lipophilicity.
Abstract
Human serum albumin microspheres were labelled with99mTc as a single step kit with radiochemical yields higher than 95%. With respect to the organ distribution in mice, the per cent of injected dose in liver was 78%.
Abstract
Technetium-99m-sestamibi (99mTc-MIBI) is a small, lipophilic and cationic compound used for myocardial perfusion imaging. In addition, 99mTc-MIBI has been shown to be useful in identifying several types of tumors, such as breast, lung and thyroid cancers. The high quality of this radiopharmaceutical and its uniformity are very important facts for application of this preparation in clinical practice. The monograph for 99mTc-MIBI recommends at least 90% radiochemical purity (RCP) for clinical use. Various factors may influence the RCP of certain reagent kits. Some of these include the amount of activity added to the reagent kit, heating time and the age of the formulated kit. The effect of these factors on RCP of 99mTc-MIBI has been investigated using high performance liquid chromatography (HPLC) and instant thin layer chromatography.
Abstract
F(ab’)2 is the fragment involved in the immunotherapy for scorpion stings and it would be convenient to label it with 99mTc for organ distribution and pharmacokinetics studies. The aim of the present study was to label scorpion antivenom F(ab’)2 with 99mTc keeping its biological activity, integrity and stability. High labeling yield was obtained using stannous chloride and sodium borohydride. Stability, immunoreactivity and integrity of 99mTc-F(ab’)2 was preserved. It was not observed any difference between potencies of unlabeled and labeled antivenom. 99mTc-F(ab’)2 can be a useful tool for use in biodistribution and pharmacokinetics studies on the evaluation of the efficacy of the antivenom against scorpion envenomation.
Abstract
99mTc pentavalent dimercaptosuccinic acid [99mTc(V) DMSA], a useful agent for imaging thyroid medullary carcinoma and other tumors can be reliably prepared by addition of Na99mTcO4 to a freeze-dried mixture of DMSA and Sn (2:1 molar ratio). The radiochemical purity, stability and animal bio-distribution behaviour is similar to that of the agent made by addition of NaHCO3 to DMSA (III) renal imaging freeze-dried kit.
Abstract
Cefuroxime axetil, a cephalosporin antibiotic used to treat bacterial infections, was investigated to label with 99mTc. Radiolabeling of cefuroxime axetil was carried out by using stannous chloride method. Effects of pH and stannous chloride amount on the radiolabeling yield were investigated. The radiochemical purity of 99mTc-cefuroxime axetil was determined by thin layer radio chromatography (TLRC), electrophoresis and high performance liquid chromatography. The maximum radiolabeling yield was 98±1%.
Abstract
The title complexes were prepared from no-carrier-added99mTc–TcO 4 – and the air-sensitive reducing ligand DMPE under argon in ethanol-water. At acidic pH [Tc(III)Cl2 dmpe2]+ was formed, while alkaline pH led to the formation of [Tc(I)dmpe3]+. About 150°C and at least 10–3M DMPE was needed to achieve over 95% yield in less than 1 hour, otherwise the [Tc(V)O2dmpe2]+ intermediate was present. Electrophoresis demonstrated the unit positive charge and reversed-phase ion-pair HPLC provided separation and identification of99mTc-products by direct comparison with known99Tc-complexes. In rats the99mTc-complexes were excreted by kidneys and liver and reached high heart/blood but only low heart/lung and heart/liver ratios. In dogs satisfactory myocardial scintigrams were obtained in spite of high liver activity.
