EP2882424A1 - STABLE PHARMACEUTICAL COMPOSITION CONTAINING 8-[(3R)-3-AMINO-1-PIPERIDINYL]-7-(2-BUTYN-1-YL)-3,7-DIHYDRO-3-METHYL-1-[(4-METHYL-2-QUINAZOLINYL)METHYL]-1H-PURINE-2,6-DIONE OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF