The present disclosure is directed to salts of N-{4-[2,4-difluoro-3-(trifluoromethyl)phenyl]-1,3-thiazol-2-yl}dimethyl-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-5-yl)acetamide and process for the preparation thereof (formula II).<;p>;SAL DE POTASIO DE LA N-[4-[2,4-DIFLUORO-3-(TRIFLUOROMETIL)FENIL]-1,3-TIAZOL-2-IL]-2-(1,3-DIMETIL-2,4-DIOXO-1,2,3,4-TETRAHIDROTIENO[2,3-d] PIRIMIDIN-5-IL) ACETAMIDA; FORMAS CRISTALINAS I Y II DE DICHA SAL; PROCESO DE PREPARACIÓ;N DE LAS FORMAS CRISTALINAS, Ú;TILES PARA EL TRATAMIENTO DEL DOLOR.<;/p>;