Perindopril tert-butylamine Imp. H (EP): (2S,3aS,7aS)-1-[(2S)-2-[(5RS)-3-cyclohexyl-2-(cyclohexylimino)-4-oxo-5-propylimidazolidin-1-yl]propanoyl]octahydro-1H-indole-2-carboxylic acid.