"(2R,3S)-2,3-Dihydroxy-2-(1-methylethyl)butanoic Acid [(1R,7aS)-2,3,5,7a-Tetrahydro-1-hydroxy-4-oxido-1H-pyrrolizin-7-yl]methyl Ester-D7; [1R-[1a,7(2R*,3S*),7aß]]-2,3-Dihydroxy-2-(1-methylethyl)butanoic Acid (2,3,5,7a-Tetrahydro-1-hydroxy-1H-pyrrolizin-7-y",Indicine Stable Isotopes