Salts of 2,6-dimethylpyrimidone derivatives and uses thereof

A pharmaceutically acceptable acid addition salt of compound (I),

• wherein the salt is hydrochloride crystal-I, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 3.68±0.2°, 10.88±0.2°, 17.30±0.2°, 22.20±0.2°, and 26.67±0.2°;
• or
• the salt is hydrochloride crystal-II, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 6.12±0.2°, 8.83±0.2°, 15.56±0.2°, 19.69±0.2°, 25.24±0.2°, and 26.35±0.2°;
• or
• the salt is hydrochloride crystal-III, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 3.46±0.2°, 10.25±0.2°, 13.62±0.2°, and 17.26±0.2°;
• or
• the salt is sulfate crystal-I, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 3.35±0.2°, 6.61±0.2°, 16.50±0.2°, and 21.43±0.2°;
• or
• the salt is tosilate crystal-I, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 6.55±0.2°, 13.74±0.2°, 20.08±0.2°, 21.32±0.2°, 22.17±0.2°, and 22.99±0.2°;
• or
• the salt is maleate crystal-I, which is characterized by an X-ray powder diffraction pattern comprising peaks expressed as 2θ at 4.10±0.2°, 16.33±0.2°, and 20.45±0.2°.