(2S)-4-oxo-4-[3-(trifluoro methyl)-5, 6-dihydro [1, 2, 4] triazolo [4,3- a]pyrazin-7(8H)-yl]-1-(2,4,5- trifluorophenyl) butan-2-amine hydrochloride monohydrate(or)(3S)-3-Amino-1-[3-trifluorome thyl)- 5,6-dihydro[1,2,4] triazolo[4,3- a]pyrazin-7(8H)-yl]-4-(2,4,5- trifluorophenyl) butan-1-one hydrochloride monohydrate.