3-[2-[4-[(Z)-(4-Fluoro-2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)piperidin-1-yl)phenyl](hydroxyimino)methyl]piperidin-1-yl]ethyl]-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one (Risperidone Impurity)