(2R,3R,4S)-3-acetamido-4-guanidino-2-((1R,2R)-1,2,3-trihydroxypropyl)-3,4-dihydro-2H-pyran-6-carboxylic acid 13C15N2;4-Guanidino-Neu5Ac2en-13C 15N2;4-Guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid-13C 15N2;5-Acetamido-2,6-anhydro-3,4,5-trideoxy-4-guanidino-D-glycero-D-galacto-non-2-enonic acid-13C 15N2;5-(acetylamino)-2,6-anhydro-4-carbamimidamido-3,4,5-trideoxy-D-glycero-D-galacto-non-2-enonic acid-13C 15N2;(2R,3R,4S)-3-acetamido-4-guanidino-2-[(1R,2R)-1,2,3-trihydroxypropyl]-3,4-dihydro-2H-pyran-6-carboxylic acid-13C 15N2;5-acetamido-2,6-anhydro-4-carbamimidamido-3,4,5-trideoxy-D-glycero-D-galacto-non-2-enonic acid-13C 15N2;5-Acetylamino-4-guanidino-6-(1,2,3-trihydroxy-propyl)-5,6-dihydro-4H-pyran-2-carboxylic acid-13C 15N2;5-Acetylamino-4-guanidino-6-(1,2,3-trihydroxy-propyl)-5,6-dihydro-4H-pyran-2-carboxylic acid(zanamivir)-13C 15N2;5-Formylamino-4-guanidino-6-(1,2,3-trihydroxy-propyl)-5,6-dihydro-4H-pyran-2-carboxylic acid-13C 15N2;4-diaminomethylamino-3-methylcarboxamido-2-(1,2,3-trihydroxypropyl)-(3R)-3,4-dihydro-2H-6-pyrancarboxylic acid(Zanamivir)-13C 15N2
