The invention relates to sulfonamide derivatives, to their use in medicine, to compositions containing them, to processes for their preparation and to intermediates used in such processes.More particularly the invention relates to a new sulfonamide Nav1.7 inhibitors of formula (I):or a pharmaceutically acceptable salt thereof, wherein Ar1, X, R1, R2, R3, R4 and R5 are as defined in the description.Nav 1.7 inhibitors are potentially useful in the treatment of a wide range of disorders, particularly pain.本發明係關於磺醯胺衍生物、其在醫學之用途、含有其之組合物、其製備方法及用於該等方法之中間物。本發明更特別關於式(I)之新穎磺醯胺Nav1.7抑制劑:或其醫藥學上可接受之鹽,其中Ar1、X、R1、R2、R3、R4及R5如說明書中所定義。Nav1.7抑制劑可適用於治療廣泛範圍之病症,尤其疼痛。