1-(9H-carbazol-4-yloxy)-3-[2-[2-[2-[[3-(9H-carbazol-4-yloxy)-2-hydroxypropyl]amino]ethoxy]phenoxy]ethylamino]propan-2-ol; Carvedilol O-Desmethyl O-Alkyl Impurity;3,3'-(((1,2-phenylenebis(oxy))bis(ethane-2,1-diyl))bis(azanediyl))bis(1-((9H-carbazol-4-yl)oxy)propan-2-ol); 1-(9H-Carbazol-4-yloxy)-3-[2-[2-[2-[[3-(9H-carbazol-4-yloxy)-2-hydroxypropyl]amino]ethoxy]phenoxy]ethylamino]propan-2-ol; Carvedilol Bisalkylpyrocatechol derivative; (3,3'-{2,2'-[1,2-Phenylenebis(oxy)]bis(ethane-2,1-diyl)}bis(azanediyl)bis(1-(9H-carbazol-4-yloxy)propan-2-ol)) (USP)