The present invention relates to a sodium salt of N-((1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl)-1-isopropyl-1H-pyrazole-3-sulfonamide and to hydrates, solvates and polymorphic forms thereof. The present invention further relates to pharmaceutical compositions comprising this compound and the use of this compound in the treatment and prevention of medical disorders and diseases, most especially by NLRP3 inhibition.