Development, in vitro and ex vivo evaluation of bioadhesive colloidal systems for curcumin skin delivery aiming the antioxidant and photoprotective activities

This work aimed to develop bioadhesive colloidal systems containing curcumin (CUR) for antioxidant and photoprotective applications. Gels and emulgels were prepared and characterized as rheology, texture profile analysis, softness, bioadhesive properties using porcine skin, skin permeability and antioxidant activity. Moreover, the formulations were investigated for their photoprotective potential using UVB-irradiated L929 fibroblasts, analyzing cellular viability with or without UVB irradiation, determination of reactive oxygen species (ROS), DNA damage, and cellular migration. The presence of CUR in the systems did not influence their mechanical textural properties and the rheological behavior (p > 0.05), displaying shear thinning characteristics, hysteresis area and rheopexy. The formulations exhibited important antioxidant activity, by scavenging radicals DPPH center dot, ABTS center dot(+), superoxide anion, and reducing ferric ions. Gel-containing CUR (GEL CUR) exhibited a less cytotoxic effect in L929 fibroblasts than free CUR, besides increasing cell viability in UVB exposure. The treatment with GEL CUR in UVB-irradiated cells attenuated oxidative stress, displaying the ability to scavenge ROS generation (31.3 %), decrease DNA damage (approximate to 30 %), and promote cellular repopulation at wound-scratch assay (8 % after 48h), which was statistically superior in comparison to the control and showing relevant activity. These colloidal systems showed suitable properties for topical application, with good antioxidant activity, permeation ability and potential application for the prevention of UVB-induced skin photodamage.