Nanoformulations of Cosmetic Interest for the Cutaneous Uptake of Nickel

Cosmetic products contain numerous metals used as pigments, UV filters, preservatives, antiperspirants and antimicrobial agents, which are responsible for allergic skin reactions, with the most common being nickel. To reduce skin penetration of Ni, innovative pharmaceutical formulations such as lipogels with chelating action against the metal ions themselves can be used. Chelation therapy allows a chelating agent to combine with metal ions to form a stable ring structure called a chelate. The chelate structure is more soluble in water than the toxic metal, which facilitates removal of the toxic metal from the tissue and its excretion by the kidneys. The aim of the following work was to evaluate the chelating properties against nickel ions of different types of lipogels containing flavonoids such as resveratrol and epigallocatechin gallate with chelating activities largely dependent on the number and position of their hydroxyl groups. The results obtained showed that lipogels based on epigallocatechin gallate show high chelating action against nickel, especially at low concentrations. In addition, rheological studies showed an ideal profile to ensure viscoelasticity and swelling of the lipogel within 48 h, confirming reports of 75% epigallocatechin release from the lipogel after 48 h. Tests have shown that lipogels based on epigallocatechin gallate have high chelating action against nickel, especially at low concentrations.