RESUMO
Nail is a strong and resistant structure, characterized by a low permeability to foreign molecules. Nails can be subjected to many diseases, among which fungal infections (e.g. onchomycosis) are the most common and responsible for nail structure alteration. Many formulations have been produced for the delivery of active ingredients to treat nail disorders, based on newly synthesized active molecules or containing chemical enhancers or chemically-modified polymers able to improve the drug transungual penetration. To avoid permanent alterations of the nail structure due to the use of chemical compounds or organic solvent-based formulation, researchers have developed novel formulations focusing on the use of new natural-based compounds. The purpose of this review is to provide information on the outcoming of natural ingredients-based formulations that have been developed in the last years as potential alternative to chemical-based formulations.