Manganese (II) chelates.

摘要

A process is provided for the preparation of Mn(II) chelates for use as contrast agents in magnetic resonance imaging, said process comprising reacting insoluble manganese (II) oxide with an aqueous suspension comprising a molar equivalent or molar excess of an insoluble protonated chelating compound conveniently at a temperature of from 20 to 50 DEG C. When the reaction is carried out with a protonated chelating agent in the absence of base, a precipitate of the protonated Mn(II) chelate is formed. A low osmolarity Mn(II) chelate solution can be formed from the precipitates by dissolving them in an aqueous solution of base. When the initial chelate forming reaction is carried out in a solution containing a molar equivalent or excess of base, a low osmolarity solution of the Mn(II) chelate is directly formed with most chelating agents. The Mn(II) chelate precipitates and low osmolarity solutions formed by the above processes are also aspects of this invention.