Pomegranate peel, an abundant agro-industrial by-product, represents a sustainable source of bioactive polyphenols, particularly punicalagin, which has been associated with antioxidant and photoprotective potential. This study aimed to develop microemulsions (MEs) containing pomegranate peel extract for dermal delivery of punicalagin using biocompatible surfactant systems. Three MEs differing in surfactant–cosurfactant composition (ME-A, ME-P, and ME-E) were prepared. Each formulation solubilized 1% (w/w) of pomegranate peel extract and was evaluated regarding in vitro release behavior, skin permeation/retention, antioxidant activity, and in vitro sun protection factor (SPF). All investigated MEs provided sustained release of punicalagin (≈10–17% of the applied dose in 8 h). ME-A, based on an alkyl polyglucoside surfactant, showed a significantly higher cumulative release of punicalagin (60.4 µg/cm2) compared with ME-E and ME-P. In skin penetration/permeation studies, ME-A also exhibited the highest numerical total delivery of punicalagin (≈48.2 µg/cm2 after 24 h), although differences among formulations were not statistically significant. All formulations demonstrated high antioxidant activity in the DPPH assay and measurable in vitro photoprotective potential, with SPF values ranging from approximately 11 to 14. Overall, pomegranate peel extract-loaded MEs showed potential as dermal delivery systems capable of improving solubilization and modulating skin delivery of punicalagin. The combination of agro-waste-derived bioactives with biocompatible surfactants highlights the potential of these systems as sustainable approaches for skincare formulations.
Pajić et al. (Mon,) studied this question.