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 crystalline form and pharmaceutical compositions, and methods for preparing said crystalline form.