High-purity texaphyrin metal complexes

A method for synthesizing a purified sample of a compound of Formula 4

• wherein R1 and R2 are independently H or C1-C6 alkyl;
• each x is independently selected from the group consisting of 2, 3, 4, 5, and 6;
• and wherein at least about 99% of the compounds of Formula 4 in the purified sample have the same structure
• comprising:
• reacting a compound of Formula 5
• with about 90% HNO3 in AcOH at about 0-5° C. for at least 30 minutes, wherein at least about 99% of the compound of Formula 4 formed in the purified sample has the same molecular weight.

A pharmaceutical composition comprising a compound according to Formula 1

• wherein:
• M is a trivalent metal cation selected from the group consisting of Gd+3, and Lu+3;
• each X is independently selected from the group consisting of OH−, AcO−, Cl−, Br−, I−, F−, H2PO4−, ClO−, ClO2−, ClO3−, ClO4−, HCO3−, HSO4−, NO3−, N3−, CN−, SCN−, and OCN−;
• R3, R4, R5, R6, R7 and R8 are independently H, OH, CnH(2n+1)Oy or OCnH(2n+1)Oy and R1, R2 are independently H or C1-C6 alkyl where
• at least one of R3, R4, R5, R6, R7 and R8 is CnH(2n+1)Oy or OCnH(2n+1)Oy, having at least one hydroxy substituent;
• n is a positive integer from 1 to 11;
• y is zero or a positive integer less than or equal to n;
• each x is independently selected from the group consisting of 2, 3, 4, 5, and 6;
• and a pharmaceutically acceptable carrier, wherein at least about 98.4% of the compounds of Formula 1 in the pharmaceutical composition have the same structure.

A method of treating a cancer comprising administering to a human patient in need thereof an effective amount of a purified composition comprising a compound of Formula 1

• wherein:
• M is a trivalent metal cation selected from the group consisting of Gd+3, and Lu+3;
• X is independently selected from the group consisting of OH−, AcO−, Cl−, Br−, I−, F−, H2PO4−, ClO−, ClO2−, ClO3−, ClO4−, HCO3−, HSO4−, NO3−, N3−, CN−, SCN−, and OCN−;
• R3, R4, R5, R6, R7 and R8 are independently H, OH, CnH(2n+1)Oy or OCnH(2n+1)Oy and R1, R2 are independently H or C1-C6 alkyl where
• at least one of R3, R4, R5, R6, R7 and R8 is CnH(2n+1)Oy or OCnH(2n+1)Oy, having at least one hydroxyl substituent;
• n is a positive integer from 1 to 11;
• y is zero or a positive integer less than or equal to n;
• each x is independently selected from the group consisting of 2, 3, 4, 5, and 6;
• and wherein at least about 98.4% of the compounds of Formula 1 in the purified composition have the same molecular weight;
• or a pharmaceutically acceptable salt, solvate, isomers, tautomers, metabolites, analogs, or prodrugs thereof.