The subject of this invention provides a method of preparation and isolation of water-insoluble or partially soluble salts of vardenafil of formula 1, in particular its salts with acids in the ratio of components 1 : 1 (of formula 2a, HA stands for any acid), and of crystalline hydrates of said salts. These solid forms, in particular crystalline vardenafil hydrochloride trihydrate of formula 4, can be directly, without additional purification, used in preparation of a medicine for the therapy of erectile dysfunction. The present solution is based on using water as a suitable medium both for obtaining of extracts of the water-soluble forms of vardenafil, and for isolation and subsequent crystallization of solid water-insoluble or partially soluble salts of vardenafil with acids (1 : 1). Crystallization of the isolated salts takes place after adjustment of pH of the aqueous solutions by means of aqueous solutions of bases or acids, wherein no organic solvent or a mixture thereof with water is needed for the crystallization. The method according to this invention reduces costs for organic solvents, increases efficiency of isolation of the vardenafil salts with acids, and facilitates preparation of poorly stable hydrates of these salts.
