Abstract

Identification and characterization of potential impurities of tizanidine hydrochloride

Author(s): Ghanta Mahesh Reddy, Singamsetty Radha Krishna, Mandava Venkata Naga Brahmeshwar Rao, Vuzzini Satish, Vurimidi Himabindu

During the analysis of laboratory batches of Tizanidine HCl, six impurities were detected by a simple isocratic reverse-phase high performance liquid chromatography (HPLC) whose area percentage ranged from0.10 to 0.30%. A thorough study has been undertaken to isolate and characterize these impurities, LCMSwas performed to identify themass number of the impurities. The structures of the impurities characterized as: N-(4,5-dihydro-1Himidazol- 2-yl)-2,1,3-benzothiadiazole-4-amine hydrochloride [impA],N-(5- chloro-2,1,3-benzothiadiazol-4-yl)thiourea (imp B), dimer of TizanidineHCl (imp C), S-methyl-N-(5-chloro-2,1,3-benzothiadiazol-4-yl)-isothiouronium iodide (impD), 4-amino-5-chloro-2,1,3-benzothiadiazole (imp E), and N,Nbis( 5-chloro-2,1,3-benzothiadiazol-4-yl)-N-(4,5-dihydro-1H-imidazol-2- yl)guanidine (imp F).