A crystalline form of the anhydrous sodium salt of 4-tert-butyl-N- [4-chloro-2- (1-oxypyridin-4-carbonyl) -phenyl] -benzenesulfonamide, wherein the crystalline form is characterized by a pattern of X-ray powder diffraction comprising at least three diffraction angles, when measured using Cu K radiation, selected from the group consisting of: 4.7, 9.1, 12.0, 14.2, 17.7, 18.1, 19.2, 19.8, 20.1, 21.3, 22.5, 24.3, 27.0, 27.2, 27.7, 28.6, 28.8, 29, 0, 30.1, 31.6, 33.5, 33.6, and 37.6 degrees 2θ +0.2 degrees 2θ.Una forma cristalina de la sal sódica anhidra de 4-terc-butil-N-[4-cloro-2-(1-oxipiridin-4-carbonil)-fenil]- bencenosulfonamida, en donde la forma cristalina se caracteriza por un patrón de difracción de polvo de rayos X que comprende al menos tres ángulos de difracción, cuando se mide utilizando radiación Cu K, seleccionados del grupo que consiste en: 4,7, 9,1, 12,0, 14,2, 17,7, 18,1, 19,2, 19,8, 20,1, 21,3, 22,5, 24,3, 27,0, 27,2, 27,7, 28,6, 28,8, 29,0, 30,1, 31,6, 33,5, 33,6, y 37,6 grados 2θ +0,2 grados 2θ.
