The Foundations of the Development of Technologies of the Synthesis of Radiopharmaceuticals

The selection of precursors (for example chelating agents) and development of a technique of chemical modification of the target molecules retaining its ability to bind to specific receptors are very important in the synthesis of radiopharmaceuticals. As some important precursors for target radiopharmaceuticals omega-iodo-aliphatic carboxylic acids and their esters can be used. We have developed an environmentally safe process for producing omega-iodoaliphatic carboxylic acids and their esters of the available, inexpensive and low toxic aliphatic cyclic ketones. We proposed a new method for the synthesis of the chelating agents omega-thia- or (bis(2-hydroxyethyl)amino)- aliphatic carboxylic acids (chelate 1 and chelate 2), which was caused by the existing disadvantages in the existing methods. Thus, based on our method the precursors (chelates) with yield of over 70-90% on the final stage were synthesized, and then the high effectiveness in producing target radiopharmaceuticals using different biomolecules was showed. 99mTc-chelates complexes were prepared with radiochemical purity >91% and found to be stable at room temperature for six hours

In Vitro Evaluation of a Specific Radiochemical Compound Based on 99mTc-labeled DARPinG3 for Radionuclide Imaging of Tumors Overexpressing Her-2/neu

It is still necessary to search for new informative diagnostic methods to detect malignant tumors with overexpression of Her-2/neu, which are characterized by the aggressive course of the disease, rapid rate of tumor growth and low rates of relapse-free and overall survival. In recent years, the radioisotope techniques for detection of specific tumor targets have been developing actively. Purpose: to develop a chemically stable radiochemical compound for the targeted imaging of cells overexpressing Her-2/neu. Material and methods: The study was performed using 2 cell lines .The human breast adenocarcinoma HER2-overexpressing cell line BT-474 was chosen to detect specific binding. As a control, HER2-negative human breast adenocarcinoma MCF-7 was used. The human breast adenocarcinoma BT-474 and MCF-7 cell lines were seeded in chamber-slides at the density of 35,000 cells/ml in trypsin-EDTA (PanEco) medium and grown overnight at 37°C. After that both cell lines were washed with Phosphate buffered saline (PBS) and distributed into test tubes to 1 ml (5 millions cells in each). After adding 100 [mu]l (70 MBq) studied complex of 99mTc-DPAH-DARPinG3 was incubated for 40 min at +4°C. Washing was performed three times with buffer PBS and 5% Bovine Serum Albumin (BSA). The characteristics of the binding specificity of the test set with the HER-2/neu receptor were determined by direct radiometric and planar scintigraphy. Nonparametric Mann-Whitney test was used to assess the differences in the quantitative characteristics between groups. Results: The output of the labeled complex was more than 91%, with a radiochemical purity of more than 94%. When carrying out a visual scintigraphic assessment much greater intensity accumulation of radiotracer was observed in the studied cell culture surface receptor overexpressing Her-2/neu. The results of direct radiometric also showed higher accumulation of the radiopharmaceutical in the adenocarcinoma cell line BT-474 human breast cancer overexpressing Her-2/neu compared to the control group. Conclusion: The preclinical studies demonstrated a high in vitro stability of the study compound, as well as its accumulation in the cell group overexpressing Her-2/neu

Liquid-Crystalline Dispersions of Double-Stranded DNA

In this review, we compare the circular dichroism (CD) spectra of liquid-crystalline dispersion (LCD) particles formed in PEG-containing aqueous-salt solutions with the purpose of determining the packing of ds DNA molecules in these particles. Depending on the osmotic pressure of the solution, the phase exclusion of ds DNA molecules at room temperature results in the formation of LCD particles with the cholesteric or the hexagonal packing of molecules. The heating of dispersion particles with the hexagonal packing of the ds DNA molecules results in a new phase transition, accompanied by an appearance of a new optically active phase of ds DNA molecules. Our results are rationalized by way of a concept of orientationally ordered “quasinematic„ layers formed by ds DNA molecules, with a parallel alignment in the hexagonal structure. These layers can adopt a twisted configuration with a temperature increase; and as a result of this process, a new, helicoidal structure of dispersion particle is formed (termed as the “re-entrant„ cholesteric phase). To prove the cholesteric pattern of ds DNA molecules in this phase, the “liquid-like„ state of the dispersion particles was transformed into its “rigid„ counterpart

The foundations of the development of technologies of the synthesis of radiopharmaceuticals

The selection of precursors (for example chelating agents) and development of a technique of chemical modification of the target molecules retaining its ability to bind to specific receptors are very important in the synthesis of radiopharmaceuticals. As some important precursors for target radiopharmaceuticals omega-iodo-aliphatic carboxylic acids and their esters can be used. We have developed an environmentally safe process for producing omega-iodoaliphatic carboxylic acids and their esters of the available, inexpensive and low toxic aliphatic cyclic ketones. We proposed a new method for the synthesis of the chelating agents omega-thia- or (bis(2-hydroxyethyl)amino)- aliphatic carboxylic acids (chelate 1 and chelate 2), which was caused by the existing disadvantages in the existing methods. Thus, based on our method the precursors (chelates) with yield of over 70-90% on the final stage were synthesized, and then the high effectiveness in producing target radiopharmaceuticals using different biomolecules was showed. 99mTc-chelates complexes were prepared with radiochemical purity >91% and found to be stable at room temperature for six hours