Disclosed are novel polymorphic trihydrated forms of the sodium salt of 4-tert-butyl-N-[ 4-chloro-2-(1-oxy-pyridine-4-carbonyl)-phenyl] benzenesulfonamide. One embodiment of the present invention is directed to a crystalline form ofthe sodium salt of 4-tert-butyl-N-[4-chloro-2-(l-oxy-pyridine-4-carbonyl)- 25 phenyl]-benzenesulfonamide (hereinafter "Compound A _ crystalline trihydrate form I"), wherein the crystalline form is characterized by an X-ray powder diffraction pattern comprising diffraction angles (°28), when measured using Cu Ka radiation, at about 4.5, 9.0, 13.6, 13.9, 15.8, 17.8, 18.2, 18.5, 19.1, 19.9, 20A, 21.2, 22.1, 22.7, 24.3, 25.0, 25.6, 26.2,26.8,27.3,27.6,28.0,28.8, and 30.8.
