My scientific activity has been oriented to the study of physical and chemical properties of compounds with biological activity. Solid state chemistry and in particular crystal engineering are the areas of research. Studies on the polymorphism of APIs have been the main subject of investigation. Particular attention has been devoted to methods of growing crystalline phases, and to the characterization of these structures, using experimental and theoretical methods. In the present, the research activity has been extended to the investigation of pharmaceutical co-crystals, a natural evolution on the study of solid phases of pharmaceutical relevance and a strategy to improve the biopharmaceutical properties of drugs. Aiming the therapeutic effectivity after oral administration, it is fundamental drug dissolution in the gastrointestinal medium and its consequent permeation across biological membranes to reach blood circulation. Drugs belonging to class biopharmaceutical IV present inappropriate absorption properties, not only because of low aqueous dissolution but also because of low permeability, generating low level of dissolved drug that leads a low bioavailability. One challenge faced in the pharmaceutical development of drugs class IV is the development of drug (solid phases) able to improve both deficient properties.