The “organomettalic aproach” to labelling of amino acids with [99mTc(CO)3(H2O)3]+

The possibilities for 99mTc-labelling of some amino acids with 99m Tc, by use of “organomettalic aproach” of labelling with [99m Tc(CO)3(H2O)3]+ precursor, were investigated. HPLC results have shown the coordination of 99mTc(I) precursor with examined amino acids. The best results were obtained at pH≅7.5 with heating.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

HPLC and spectrophotometric investigation of the formation of Sn(II)-p-aminohippuric acid complex in perchlorate medium

The complex equilibrium in tin(II)-p-aminohippuric acid (PAH) solutions in perchlorate medium was investigated. HPLC, spectrophotometric and pH-metric methods were used. The experimental results have shown that week mononuclear complex of the general composition PAH/Sn(II)=1/1 was formed.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Tricarbonyl technetium(I) complexes with different phosphate ligands

The possibilities for labelling of different phosphate ligands with technetium-99m through [99m Tc(CO)3(H2O)3] + precursor were investigated. The HPLC results have shown that hydrophilic organometallic [ 99mTc(CO)3(H2O)3] + precursor allows forming of Tc (I) complexes with different phosphate ligands, based on the tricarbonyltechnetium (I) core.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Physico-chemical characterization of 90Y-labeled antimony trisulfide colloid and comparison with 99mTc-labeled one

In radionuclide therapy, the importance of 90Y as a beta-emitting radionuclide is increasing rapidly. The properties of the 90Y-labeled antimony trisulfide colloid (Sb2S3) were compared with the 99mTc-labeled one. Labeling efficiencies reached >96% and >97% for 90Y- and 99mTc-labeled colloids respectively. Both preparations were stable for 72 h in saline and 1% albumin solution. Filtration analysis showed that more than 94% of total 90Y radioactivity is associated with the colloidal particles smaller than 20 nm, while more than 90% of 99mTc radioactivity is associated with the particles retained on the filter with a 20 nm pore size. 90Y-labeled colloids showed high labeling efficiency, stability and potency for clinical use.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Tricarbonyltechnetium (I) labelled ligands with nso donor atom set: in vitro and in vivo evaluation

There is an increasing interest for the 99mTc labelling of biomolecules by using bifunctional chelating agents. To find new ligand, which can be linked to the small biomolecules and coordinated with technetium-99m tricarbonyl complexes, is a challenging task. The investigated NSC and NSC5 ligands allow the preparation 99mTc(I) stable complexes in high yield. The 99mTc complexes were characterized by comparing their HPLC profiles with those of the respective Re(I) compounds. Biodistribution and stability studies were carried out, including challenge with histidine. These complexes also proved to be stable in vivo and showed a very good biological behaviour. The radiochemical and biological features of the novel 99mTc complexes, as well as, the nature of the ligands, make them very promising candidates for labelling of tumour specific biomolecules.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Evalaution of radioiodination of synthesised meta-iodobenzylguanidine catalyzed by in situ generated Cu(i)

Meta-iodobenzylguanidine (m-IBG) is a biogenic amine precursor, noradrenaline analogue, which is actively taken up by tumors. In tracer amounts, [123/131I]-m-IBG is used as a radiopharmaceutical to target normal and malignant tissues of neuroadrenergic origin for diagnostic scintigraphy, and labeled with higher activities of 131I, it is used for therapy of phenochromocytoma and neuroblastoma. The increased clinical therapeutic use of unlabeled m-IBG at doses of up to 40 mg/m2 emphasizes the need for syntheses and an established quality protocol for this substance that relies on verifiable analytical parameters. Evaluation of radioiodination was necessary to obtain higher labeling yield (we achieved over 90% instead no more than 70%), because isotopic exchange labeling of m-IBG with 131I catalyzed by Cu(I) is much more efficient than with conveniently used ammonium sulphate.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Electrochemical separation of 90-yttrium in the electrochemical 90Sr/90Y generator and its use for radiolabelling of DOTA-conjugated somatostatin analog [DOTA0, Tyr3] octreotate

Radiopharmaceuticals based on 90Y are widely used in the treatment of malignant deseases. In order to meet the requirements for their future application, a 90Sr/90Y generator was developed and 90Y eluted from this locally produced generator was used for the radiolabelling of the DOTA-conjugated somatostatin analog [DOTA0,Tyr3] octreotate and the preparation of [90Y-DOTA0,Tyr3] octreotate (90Y-DOTATATE) for peptide receptore radionuclide therapy. 90Sr/90Y generator was based on the electrochemical separation of 90Y from 90Sr in a two-cycle electrolysis procedure. Three electrode cells were used to perform both electrolyses. In both cycles, working electrodes were kept on constant potential. The pH of the solution was adjusted to 2.7 of the value before the electrolyses. The radionuclidic purity of the 90Y solution was analysed by ITLC and extraction paper chromatography. The labelling of peptide (100 mg DOTATATE) with 90YCl3 was performed at 95°C for 30 minutes. Radiochemical purity was determined by HPLC and chromatographic separation, using a solid SepPak C-18 column. Results obtained confirmed the efficiency of our electrochemical separation technique and quality control methods for 90Y. The achieved efficiency of the 90Sr/90Y generator above 96% of the theoretical value represents a good basis for the further development of this generator. The labelling of the DOTATATE with 90Y exhibited a high efficiency, too: there was less than 1% of 90Y3+in the 90Y-DOTATATE

Radiochemical purity and particles number determinations of modified Tc-99m-macroaggregated albumin

A new procedure for the aggregation of human albumin and Tc-99m-labelling of the prepared macroaggregated albumin are presented. Simple methods for quantifying of all the radiochemical impurities existing in Tc-99m-MAA were tested. Thus, 85% methanol was used as the mobile phase in paper and ITL chromatography with Whatman N-o 1 and ITLC-SA strips. A system of two solvents (acetone and 1 M NaCl or 0.9% NaCl) was used for 3 MM paper, ITLC-SA and ITLC-SG strips and silica gel plates as the stationary phase. Low-voltage paper electrophoresis with Whatman 3 MM paper sheets soaked in barbiturate buffer and the gel chromatography column method (Sephadex G-25) were also applied. Filtration through syringe filters, proposed by European and Yugoslav Pharmacopoeia, was performed for comparison. The application of the mentioned tests lead to consistent results for the labelling efficiency ( GT 98.5%) and percent radiochemical impurities of Tc-99m-MAA. Determination of the particles number in a counter chamber and their size distribution under a light microscope with a calibrated ocular scale gave the result of 300000-350000 particles per 1 mg of HA. This confirmed that the human albumin macroaggregates prepared by our new procedure is remarkably improved and convenient for routine diagnostic purposes

99mTc-hexakis-(2-metoxy-isobutyl-isonitrile) ( 99mTc-MIBI) a new myocardial imaging agent: synthesis of MIBI, optimising conditions for radiolabelling with 99mTc at high radiochemical purity and in vivo behavior

99mTc-MIBI is a promising radiopharmaceutical for myocardial perfusion imaging agent, but it has also shown good results in identifying several types of tumors, such as breast, lung and thyroid cancers. It is a lipophilic, cationic technetium (1) complex. In this paper a complete study on the synthesis of 2-metohy-isobutyl-isonitrile (MIBI) as well as a formulation of a lyophilized kit for labeling with 99mTc is presented. Investigation on effective factors as well as finding out the optimum parameters to obtain the highest labelling efficiency and radiochemical purity of 99mTc-MIBI complex were performed. The radiochemical purity of the labelled preparation was high (>95%). Biodistribution study performed in health male Wistar rats showed satisfactory biokinetics results. 99mTc-MIBI was accumulated in sufficient amount into the hearth tissue for myocardial perfusion imaging. MIBI in kit formulation was found to be stable and also safe for administration.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Development of 90Sr/90Y generator using electrochemical separation

Using of radiopharmaceuticals based on 90Y in the treatment of solid cancer is increasing in recent years. Therefore, generators have been developed for obtaining the 90Y using a feature of 90Sr for spontaneous breakthrough and its equilibrium with 90Y. Electrochemical separation of 90Y from 90Sr has become the basic method for obtaining 90Y in high radiochemical yield. For the preliminary study, we used the electrochemical system with two electrochemical cells. Quality control was performed using extraction paper chromatography (EPC). Preliminary results showed that the separation completed successfully in both ways, quantity and quality