Hydroxy Brimonidine;Hydroxy BriMonidine Trifluoroacetate Salt;Hydroxy BriMonidine Trifluoroacetic Acid Salt;Brimonidine EP Imp G;Brimonidine tartrate Imp G (EP) as Hydrochloride salt: 1-(2-Aminoethyl)-3-(5-bromoquinoxalin-6-yl)urea Hydrochloride;Brimonidine EP Impurity G HCl;Brimonidine Related Impurity 1;Urea, N-(2-aminoethyl)-N'-(5-bromo-6-quinoxalinyl)-