5-[(2-chloroethyl)(2-hydroxyethyl)amino]-1-methyl-1H-Benzimidazole-2-butanoic acid hydrochloride ; 4-(5-((2-Chloroethyl)(2-hydroxyethyl)amino)-1-methyl-1H-benzo[d]imidazol-2-yl)butanoic acid hydrochloride ; Bendamustine Monohydroxy Acid Impurity ; Bendamustine USP Related Compound E (HCl); 4-(5-((2-Chloroethyl)(2-hydroxyethyl)amino)-1-methyl-1H-benzo[d]imidazol-2-yl)butanoic acid hydrochloride; 1H-Benzimidazole-2-butanoic acid, 5-[(2-chloroethyl)(2-hydroxyethyl)amino]-1-methyl-, hydrochloride (1:1); 1H-Benzimidazole-2-butanoic acid, 5-[(2-chloroethyl)(2-hydroxyethyl)amino]-1-methyl-, Monohydrochloride; Bendamustine Related Compound E (USP - Base);