A polymorphic form APO-I of Ezogabine, processes for the preparation thereof and pharmaceutical formulations comprising the polymorphic form APO-I are provided. The polymorphic form APO-I of Ezogabine of present invention offers an improved solubility profile. Ezogabine, also known as Retigabine, is indicated as adjunctive treatment of partial-onset seizures in patients aged 18 years and older.La présente invention concerne une forme polymorphe APO-I dézogabine, des procédés de préparation de celle-ci et des formulations pharmaceutiques comprenant la forme polymorphe APO-I.