5-Vinylpyrrolidone isopropyl dichloroacetate 2-Pyrrolidinecarboxamide,1-(hydroxyacetyl)-,(S)-(9CI) 1,3,5,7-tetrahydroxyadamantane Vildagliptin Impurity 19 N-acetic acid-1-aMino-3-adaMantanol Vildagliptin IMpurity 2 (Mixture of DiastereoMers) Vildagliptin Impurity 6 Vildagliptin Impurity 25 CYCLO(-GLY-PRO) 2-Pyrrolidinecarbonitrile,1-acetyl-,(2S)-(9CI) 2-Pyrrolidinecarbonitrile, 1-(2-aminoacetyl)-, hydrochloride (1:1), (2S)- Vildagliptin Related Compound H Vildagliptin Dione Impurity Vildagliptin Impurity 34 Vildagliptin Impurity 38 1,3,5,7-Tetranitroadamantane N-methylpyrrolidine-2-carboxamide