(2S,3aS,6aS)-1-[(2S)-2-[[(1S)-1-(Ethoxycarbonyl)-3-(phenyl-d5)propyl]amino]-1-oxopropyl]octahydrocyclopenta[b]pyrrole-2-carboxylic Acid,(2S,3aS,6aS)-1-[(2S)-2-[[(1S)-1-(Ethoxycarbonyl)-3-(phenyl-d5)propyl]amino]-1-oxopropyl]octahydrocyclopenta[b]pyrrole-2-carboxylic Acid,"Labeled Ramipril, intended for use as an internal standard for the quantification of Ramipril by GC- or LC-mass spectrometry.",Ramipril Stable Isotopes