Famotidine EP Impurity - E

2,2'-[disulfanediylbis(methylenethiazole-4,2-diyl)]diguanidine; Bis[(2-guanidino-4-thiazolyl)methyl]disulfide; N,N'''-[Dithiobis(methylene-4,2-thiazolediyl)]bisguanidine; 2,2'-[4,4'-Disulfanediylbis(methylene)bis(thiazole-4,2-diyl)]diguanidine, Famotidine Related Compound E (USP);