The invention relates to the salt of naphthalene-1,5-disulfonic acid with (R)-3-(6-amino-pyridin-3-yl)-2-(1-cyclohexyl-1H-imidazol-4-yl)ethyl propionate, which can be represented by the following structural formula of formula (I), to methods for the production thereof, to drugs containing said salt, and to the use of said drugs to treat diseases that are accompanied by thromboses, embolisms, hypercoagulability, or fibrotic changes.