Authors: I.G. Meerovich, G.A. Meerovich, O.V. Dolotova, A.A. Uchevatkin, O. Yu. Saveliev, N.V. Andronova, N.A. Oborotova, O.L. Kaliya, Yu.A. Pirogov, G.N. Vorozhtsov, A. Yu.Baryshnikov
Affilation: N.N. Blokhin Russian Cancer Research Center or RAMS, Russian Federation
Pages: 15 - 17
Keywords: magnetic resonance imaging, contrasting agent, manganese, phthalocyanine, micellar dispersion
Contrast agents (CA) are used to increase tumor contrasting in magnetic resonance imaging (MRI). The work is devoted to estimation of Manganese chloride tetra-3-phenylthio-tetra-5-tert-buthylphthalocyanine [3-(PhS)4-5-(t-Bu)4PcMnCl] as potential CA for MRI. We have developed the micellar dispersion of 3-(PhS)4-5-(t-Bu)4PcMnCl based on 4% Emuxol-268 solution with particle size in a range of 170-180 nm. Dynamics of 3-(PhS)4-5-(t-Bu)4PcMnCl accumulation was studied on F1 mice bearing Ehrlich tumor by absorbance of sensitized biological tissue. MRI studies were performed on Wistar rats bearing subcutaneous glioma C6. Magnetic relaxivity R1 of potential CA was estimated from rates of magnetic relaxation 1/T1 in micellar dispersions with different content of the substance using Avance 600 spectrometer with 15 T magnetic field. MRI investigations were performed using Biospec 70/30 tomography system with 7.0 T magnetic field applying the T1-weighted spin-echo protocol. Investigation of 3-(PhS)4-5-(t-Bu)4PcMnCl absorption in animal tissue in vivo has shown that this CA is selectively accumulated in tumor and cleared from the normal tissue by 50 hours after injection. The selectivity index of 4 by 4-5 hours after administration and relaxivity R1 up to 5.0 mM-1sec-1 provides 70% enhancement of contrast of C6 glioma on MRI image by administration of 3-(PhS)4-5-(t-Bu)4PcMnCl at dose of 6 mg/kg.