Metformin EP Impurity E Catalogue M422575 CAS 36801-25-9 M.W 115.14 49.04 18.02 M.F C3H9N5.1/2H2SO4.H2O Specifications FAQs Chemical Name: Metformin EP Impurity ESynonyms: N-Desmethyl Metformin Hemisulfate MonohydrateCAS No.: 36801-25-9 (sulfate salt) ;1674-62-0 (HCl salt);1609-00-3 (base)