Formulations of bendamustine

A liquid bendamustine-containing composition, comprising:

• a) bendamustine or a pharmaceutically acceptable salt thereof;
• and
• b) a pharmaceutically acceptable fluid comprising propylene glycol, polyethylene glycol and a stabilizing amount of an antioxidant selected from the group consisting of thioglycerol, monothioglycerol, lipoic acid, propyl gallate, methionine, cysteine, metabisulfites, sodium formaldehyde sulfoxylate, phenol-containing aromatic and aliphatic compounds and dihydrolipoic acid;
• the bendamustine-containing composition having less than or equal to 0.12% total PG esters at about 15 days of storage at a temperature of about 25° C.;
• wherein the ratio of polyethylene glycol to propylene glycol is selected from the group consisting of:
• about 95:5, about 90:10, about 85:15, about 80:20 and about 75:25.

A liquid bendamustine-containing composition, comprising:

• a) bendamustine or a pharmaceutically acceptable salt thereof;
• and
• b) a pharmaceutically acceptable fluid comprising about 5% to about 10% propylene glycol, polyethylene glycol and a stabilizing amount of an antioxidant selected from the group consisting of thioglycerol, monothioglycerol, lipoic acid, propyl gallate, methionine, cysteine, metabisulfites, sodium formaldehyde sulfoxylate, phenol-containing aromatic and aliphatic compounds and dihydrolipoic acid;
• wherein the ratio of polyethylene glycol to propylene glycol is selected from the group consisting of:
• about 95:5, about 90:10, about 85:15, about 80:20 and about 75:25.