Provided herein are (8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one tosylate salt forms, including crystalline forms, and methods of their preparation. Pharmaceutical compositions comprising a (8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one tosylate salt are also provided, as are methods of using (8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one tosylate salt to treat a disease or condition, such as a cancer.本文提供(8S,9R)-5-氟-8-(4-氟苯基)-9-(1-甲基-1H-1,2,4-三唑-5-基)-8,9-二氫-2H-吡啶并[4,3,2-de]呔-3(7H)-酮甲苯磺酸鹽形式(包含結晶型形式),及其製備方法。本文亦提供包括(8S,9R)-5-氟-8-(4-氟苯基)-9-(1-甲基-1H-1,2,4-三唑-5-基)-8,9-二氫-2H-吡啶并[4,3,2-de]呔-3(7H)-酮甲苯磺酸鹽之醫藥組合物,亦提供使用(8S,9R)-5-氟-8-(4-氟苯基)-9-(1-甲基-1H-1,2,4-三唑-5-基)-8,9-二氫-2H-吡啶并[4,3,2-de]呔-3(7H)-酮甲苯磺酸鹽來治療諸如癌症等疾病或病況之方法。