Calmangafodipir, a New Chemical Entity, and Other Mixed Metal Complexes, Methods of Preparation, Compositions, and Methods of Treatment

A mixed metal complex of a compound of Formula I, or a salt thereof, wherein the mixed metals comprise a Group III-XII transition metal and a Group II metal:

• wherein
• X represents CH or N,
• each R1 independently represents hydrogen or —CH2COR5;
• R5 represents hydroxy, ethylene glycol, glycerol, optionally hydroxylated alkoxy, amino or alkylamido;
• each R2 independently represents ZYR6 wherein Z represents a bond, CO, or a C1-3 alkylene or oxoalkylene group, optionally substituted by R7;
• Y represents a bond, an oxygen atom or NR6;
• R6 is a hydrogen atom, COOR8, alkyl, alkenyl, cycloalkyl, aryl or aralkyl group, optionally substituted by one or more groups selected from COOR8, CONR82, NR82, OR8, ═NR8, ═O, OP(O)(OR8)R7 and OSO3M;
• R7 is hydroxy, optionally hydroxylated, optionally alkoxylated alkyl or aminoalkyl group;
• R8 is a hydrogen atom or an optionally hydroxylated, optionally alkoxylated alkyl group;
• M is a hydrogen atom or one equivalent of a physiologically tolerable cation;
• R3 represents a C1-8 alkylene, a 1,2-cykloalkylene, or a 1,2-arylene group, optionally substituted with R7;
• and
• each R4 independently represents hydrogen or C1-3 alkyl.