Formoterol EP Impurity F; Formoterol Dimer; Formoterol Fumarate EP Impurity F; N-[2-hydroxy-5-[1-[[2-hydroxy-5-[1-hydroxy-2-[[2-(4-methoxyphenyl)-1-methylethyl]amino]ethyl]phenyl]amino]-2-[[2-(4-methoxyphenyl)-1-methylethyl]amino]ethyl]phenyl]formamide; N-(2-Hydroxy-5-(1-((2-hydroxy-5-(1-hydroxy-2-((1-(4-methoxyphenyl)propan-2-yl)amino)ethyl)phenyl)amino)-2-((1-(4-methoxyphenyl)propan-2-yl)amino)ethyl)phenyl)formamide; FORMOTEROL FUMARATE DIHYDRATE IMPURITY F [EP IMPURITY]; Formoterol EP Impurity F (Mixture of Diastereomers)