The invention relates to a method of identifying protein CAMs (constitutively active mutants) wherein a library of mutated sequences of a protein is generated, yeast cells are transformed with such a library, and the respective protein CAM is identified. Moreover the invention relates to the use of such a method for identifying agonists or inverse agonists.Izum se odnosi na postupak za proizvodnju lijekova koji sadržavaju vardenafil hidroklorid, u biti kao trihidrat u čvrstom obliku, i na lijekove koji se mogu dobiti u skladu s tom metodom.