Search Results
Abstract
The preparation of N1-(octadecylcarbomyl-methy)-ethylenediaminetriacetic acid labelled with99mTc is described. Reduction of technetium was made using sodium borohydride (procedure A) or stannous chloride (procedure B), and the labelling efficiency was checked by thin layer chromatography. Preliminary studies of biol-behavior of this complex were performed in white rats.
Abstract
A series of bidentate and tetradentate ligands with azomethine and Ar–OH functional groups derived from salicylaldehyde and primary alkyl or aryl monoamines and diamines has been synthesized and labeled with99mTc at various pH's using stannous chloride as reducing agent. The labeling efficiency was monitored by thin layer and paper chromatography.
Abstract
This study examined the applications of novel non-polymer magnetic ferrite nanoparticles (Fe3O4 NPs) labeled with 99mTc-pertechnetate (99mTcO4 −). The radiochemistry, chemistry, and biodistribution of Fe3O4 NPs labeled with 9mTcO4 − were analyzed. This paper employed instant thin layer chromatography and magnetic adsorption to evaluate the labeling efficiency and stability of 99mTc-Fe3O4 at various reaction conditions. A scanning electron microscope, X-ray diffractometer, Fourier transform infrared spectrometer, laser particle size analyzer, and superconducting quantum interference device magnetometer were used to analyze the physical and chemical properties of the Fe3O4 and 99Tc-Fe3O4 nanoparticles. The biodistribution and excretion of 99mTc-Fe3O4 were also investigated. Radiochemical analyses showed that the labeling efficiency was over 92% after 1 min in the presence of a reducing agent. Hydroxyl and amine groups covered the surface of the Fe3O4 particles. Therefore, 99Tc (VII) reduced to lower oxidation states and might bind to Fe3O4 NPs. The sizes of the 99Tc-Fe3O4 NPs were about 600 nm without ultrasound vibrations, and the particle sizes were reduced to 250 nm under ultrasound vibration conditions. Nonetheless, Fe3O4 NPs and 99Tc-Fe3O4 NPs exhibited superparamagnetic properties, and the saturation magnetization values were about 55 and 47 emu/g, respectively. The biodistribution showed that a portion of the 99mTc-Fe3O4 nanoparticles might embolize in a pulmonary capillary initially; the embolism radioactivity was cleared from the lungs and was then taken up by the liver. 99mTc-Fe3O4 metabolized very slowly only 1–2% of the injected dose (ID) was excreted in urine and about 2.37% ID/g was retained in the liver 4 h after injection. Radiopharmaceutically, 99mTc-Fe3O4 NPs displayed long-term retention, and only 99mTc-Fe3O4 NPs that dissociated to free pertechnetate could be excreted in urine. This research evaluated the feasibility of non-polymer magnetic ferrite NPs labeled with technetium as potential radiopharmaceuticals in nuclear medicine.
Abstract
A new diiodine substituted IDA derivative, 2,4-diiodine-6-methyl IDA (DIIODIDA) was synthesized and labeled with99mTc. It was established that99mTc-DIIODIDA had high radiochemical purity. Biodistribution and influence of bilirubin on99mTc-DIIODIDA biokinetics has been studied in rats and compared to the corresponding results for99mTc-SOLCOIODIDA. Related to99mTc-SOLCOIODIDA,99mTc-DIIODIDA has much better biliary exretion (55.18 versus 43.63%). No change of99mTc-DIIODIDA biokinetics, under influence of bilirubin was noticed. Biliary excretion of99mTc-SOLCOIODIDA has been reduced for about 60%. The protein binding of99mTc-DIIODIDA and99mTc-SOLCOIODIDA were also determined, using in vitro method of precipitation. These results showed that99mTc-DIIODIDA hepatobiliary imaging agent is superior to the presently used99mTc-monoiodine IDA derivatives.
Abstract
The labelling of 1,3-n alkylpropanedithiols and of 15-/1,3-dimercapto 2-propyl/ pentadecanoic acid by99mTc has been performed by an exchange reaction with the hexachlorotechnetate ion99mTcCl 6 2– and by reduction of99mTcO 4 – with Sn/II/ in the presence of the ligand. The biological distribution of the exotechnetium complexes obtained by the latter method in mouse does not reveal a high tropism of these labelling compounds in relation to a particular tissue.
Abstract
Localizing and distinguishing the “infection” in body sites are very important and life saving processes. Scintigraphic detections may help to determine the sites of inflammation and infection. At this point, nuclear medical imaging may proceed one step further and be helpful to localize and distinguish the inflammation. The radiolabeled antibiotic 99mTc-Cefuroxime axetil was assessed as an infection imaging agent in a rat model. In this study, 99mTc-Cefuroxime axetil was examined in localizing the normal, sterile inflamed, and septic inflamed rat muscle tissues, and also in distinguishing each of them. The biodistribution data show that 99mTc labeled Cefuroxime axetil was retained in infectious areas. The retention was better in septic inflamed (S. aureus) area than sterile inflamed area. The clearance of the labeled antibiotic from other tissues is rapid on the contrary to its clearance from the septic area. Target/non-target ratio shows a good value of 2.5 at 4-hour post injection when the activity of the other organs is cleared by urinary excretion.
Abstract
The interaction of bilirubin and99mTc-HIDA and99mTc-IODIDA has been studied in rats. The mechanism of this interaction has been examined at the level of binding with human serum albumin (HSA) by the in vitro method. Percentage of binding with HSA, and affinity constants for99mTc-IODIDA were determined with and without bilirubin. Bilirubin was labeled with99mTc and its interaction with HSA was also examined.
Abstract
The organometallic precursor of fac-[99mTc(CO)3(H2O)3]+ has attracted much attention because of the robustness and small size of Tc(I)-tricarbonyl complexes compared to Tc(V) complexes and the good labeling affinity with a variety of donor atoms. Among various ligand systems, an iminodiacetic acid (IDA) was proven as a good chelating group to form a Tc(III)-compelx as well as has been shown its potential as a chelating system for fac-[99mTc(CO)3] precursor. In an attempt to confirm the similarity and the difference between 99mTc(CO)3-IDA and 99mTc-(IDA)2-complex, M(CO)3-IDA (M = 99mTc, Re) complexes of disofenin, mebrofenin and N-(3-iodo-2,4,6-trimethyl phenylcarbamoylmethyl) iminodiacetic acid were prepared, and the biological evaluation of 99mTc(CO)3-disofenin was performed. The 99mTc(CO)3-IDA complexes were prepared with a high radiolabeling yield (>98%) in a quantitative manner and showed a negative charge. The in vivo pharmacokinetic behavior of 99mTc(CO)3-disofenin showed a similar biological activity to 99mTc-(disofenin)2 in that those complexes were quickly cleared from the blood by the hepatocytes and excreted into the gallbladder and intestine. Accordingly, the 99mTc(CO)3-IDA derivatives of disofenin and mebrofenin might be used as hepatobiliary imaging agents. Since an IDA is a promising chelator for 99mTc-based radiopharmaceutical and the biological properties of 99mTc(CO)3-IDA derivative shows similar to that of 99mTc-complex, a biomolecule containing IDA can be freely radiolabeled with fac-[99mTc(CO)3]-precursor or 99mTc. However, the radiolabeling efficiency and the biological behavior demonstrates the favorable properties of 99mTc(CO)3-IDA compound for the development of a new imaging agent.
Abstract
Mercaptoacetyltriglycine and its related compounds were synthesized and labeled with99mTc-radionuclide in order to study the effect of substituents and labeling conditions upon the formation of radioactive by-products. Direct labeling and ligand exchange reactions were followed by radio-TLC separation. The direct labeling in alkaline media at elevated temperature provides high radiochemical yields and gives opportunity for a new kit formulation because the neutralization to physiological pH does not cause any change in the chemical identity of the complexes. Compounds with the strongly polar sulfonyl groups show significantly lower protein binding compared with mercaptoacetyltriglycine and may be considered as potential renal agents.
Abstract
A modified99mTc(Sn)-pyrophosphate (PyP) kit for the application in nuclear cardiology (radioventriculography, angiocardiography, scintigraphy of blood pool) was developed. Each vial contains 12 mg PyP (Na4P2O7), 4 mg SnCl2·2H2O, 2.5 mg gentisic acid and 10 mg NaCl. The reconstitution is performed by dissolving the lyophilized kit in 3 ml 0.9% NaCl. In comparison with the standard pyrophosphate kit for bone scanning and detection of miocardial infarction, it contains an increased amount of Sn(II) so that the molar ratio ligand/reductant is lowered from 25 to 2.5. The radiochemical analyses showed that the radiochemical purity of the labeled kit is high (>90%) during three hours after addition of99mTc-activity. The shelf-life of the inactive freeze-dried preparation is up to four months providing that it is kept in vacuum and at appropriate temperature (2–8°C). The biodistribution studies revealed increased accumulation in blood and low uptake by liver and kidneys. It was concluded that the modified kit performs stable and reproducible properties.
