METHOD OF PRODUCING NANODISPERSED MAGNETOACTIVE RADIO-OPAQUE AGENT Russian patent published in 2019 - IPC A61K49/04 

FIELD: medicine.

SUBSTANCE: invention refers to roentgenology, and can be used as radiopaque means for X-ray examinations of various organs. Method involves precipitation of Fe₃O₄ magnetite from a solution containing iron (II) and iron (III) salts, with a concentrated solution of ammonia at pH value of the reaction mixture of not less than 10 in the presence of a stabilizer - citric acid, taken at rate of 0.02–0.5 mol per 1 mol of stoichiometric colloidal Fe₃O₄, which is treated in autoclave at 100 °C for 20–30 minutes, then at 180 °C for 12–16 hours, after which is separated by decantation on external magnet and washed. Adding to obtained settling aqueous ammonia solution, then, citric acid and a tantalum solution in hydrofluoric acid are added to the obtained suspension at pH of the reaction mixture of 9–11. Processing the obtained mixture in autoclave at 100 °C for 20–30 minutes, then at 180 °C for 12–16 hours to obtain precipitate of ferrimagnetic particles of Fe₃O₄ 70–400 nm in size coated with X-ray contrast coating of tantalum Ta₂O_5. Obtained residue is filtered and washed.

EFFECT: technical result is higher stability of obtained magnetoactive radio-opaque agent for sedimentation, improved stability of its aqueous suspension due to optimization of dimensions of its particles with simultaneous increase in strength and high adhesion of their radiopaque coating to ferrimagnetic core.

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