Metformin Related Compound B; Metformin Impurity E HCl Salt; Metformin EP Impurity E HCl; Imp. E (EP) as Hydrochloride:1-MethylbiguanideHydrochloride; 1-Methylbiguanide hyrdochloride (Metformin RCB); 1-(diaminomethylidene)-2-methylguanidine,hydrochloride; Metformin Impurity 5(HCl)