This invention relates to a new crystalline form of the succinate salt of the epithelial sodium channel (ENaC) blocker 3-(3- {2-[(E)-3,5-Diamino-6-chloro-pyrazine-2-carbonylimino]- 1,3,8- triaza-spiro[4.5]decane-8-carbonyl} -benzenesulfonylamino)- propionic acid dipropylcarbamoylmethyl ester, pharmaceutical compositions comprising said crystalline form, uses of said crystal line form and pharmaceutical compositions, and methods for preparing said crystalline form.