Biamine ; N,N'-[[(1-Methylethyl)imino]-bis[(2-hydroxypropane-1,3-diyl)oxy(3-acetyl-1,4-phenylene)]]dibutanamide; N,N'-((((isopropylazanediyl)bis(2-hydroxypropane-3,1-diyl))bis(oxy))bis(2-acetyl-4,1-phenylene))dibutyramide; Acebutolol Dimer Impurity;Acebutolol Hydrochloride - Impurity G;