pharmaceutically acceptable salts of - 7 -- butyryl ]- 3 - trifluoromethyl - 5 , 6 , 7 , 8 - tetrahydro - imidazopyrazine - 1 - formic acid , their preparation methods , compositions containing the said pharmaceutical salts and their use as medicaments , especially as dipeptidyl peptidase iv inhibitors are disclosed . of the many acceptable salts , one example is the following .