9-(4-(5-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)-3-(2-(4-(5-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl-d4)-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one,9-(4-(5-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)-3-(2-(4-(5-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl-d4)-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one,Paliperidone Impurity