Famotidine Related Compound A Dihydrochloride; Famotidine Impurity 1(Famotidine EP Impurity A); Famotidine Related Compound A Dihydrochloride; Famotidine Impurity 1; Famotidine Dihydrochloride; ethyl 3-(((2-((diaminomethylene)amino)thiazol-4-yl)methyl)thio)propanoate; Famotidine EP Impurity A DiHCl; Propanimidamide,3-[[[2-[(aminoiminomethyl)amino]-4-thiazolyl]methyl]thio]-,dihydrochloride; Famotidine Impurity 1 Dihydrochloride (Famotidine EP Impurity A Dihydrochloride)