A process for preparing an optionally substituted 4-benzimidazol-2-ylmethylamino)benzamidine, the process comprising: (a) condensing an optionally suitably substituted diaminobenzene with 2-[4-(1,2,4-oxadiazol-5-on-3-yl)phenylamino]acetic acid; (b) hydrogenating the product obtained from step (a); and (c) optionally carboxylating the amidino group of the product obtained from step (b).