2,2′-[pentane-1,5-diylbis[oxy(3-oxopropane-1,3-diyl)]]bis[1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinolinium] dibenzenesulfonate (as per EP);2-(2-Carboxyethyl)-1,2,3,4-tetrahydro-6,7-dimeth oxy-2-methyl-1-veratrylisoquinolinium benzenesulfonate, pentamethylene ester (as per USP); Atracurium Besylate - API (IP); 2,2'-[1,5-Pentanediylbis[oxy(3-oxo-3,1-propanediyl)]]bis[1-[(3,4-dimethoxyphenyl)methyl]-1,2,3,4-tetrahydro-6,7-dimethoxy-2-methyl-isoquinolinium Benzenesulfonate; Atracurium Dibesylate; BW 33A; Tracrium; Tracur; Wellcome 33A74;2,2′-[1,5-Pentanediylbis[oxy(3-oxo-3,1-propanediyl)]]bis[1-[3,4-dimethoxyphenyl)methyl]-1,2,3,4-tetrahydro-6,7-dimethoxy-2-methylisoquinolinium]dibenzenesulfonate(USP)