The present invention relates to a novel amorphous form of the dihydrogenphosphate salt of (2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-.alpha.]- pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine of structural formula I as well as a process for its preparation, pharmaceutical compositions containing this novel form, and methods of use of the novel form and pharmaceutical compositions for the treatment of diabetes, obesity, and high blood pressure. ##STR00001##