Phytosomal nanocarriers as platforms for improved delivery of natural antioxidant and photoprotective compounds in propolis: An approach for enhanced both dissolution behaviour in biorelevant media and skin retention profiles.

Propolis has been reported to possess rich content of antioxidant compounds and may provide health benefits through oxidative stress reduction. Presently, the formulation activities used to enhance the drug delivery have been hampered due to inherently low aqueous solubility and poor transdermal permeation of the bioactive phenols and flavonoids. Here, we show, the formulation of propolis extract (PE) into phytosome delivery systems. The optimum antioxidant activity was attained through extraction process using 75% v/v ethanol. The phytosome was prepared using thin-layer hydration technique with l-α-Phosphatidylcholine as a phospholipid. Fourier transform infrared (FTIR) was used to investigate the occurrence of molecular interactions between formulation components. This innovative approach could encapsulate >40% of bioactive compounds in PE, namely caffeic acid, quercetin, and kaempferol. FTIR spectroscopy indicated new hydrogen bond formation, supporting successful phytosome formulation. The phytosomes enhanced the dissolution up to 4-folds of bioactive compounds in bio-mimicked release media, as well as improved penetrability and skin retention up to 6-folds of the three main compounds of propolis, when compared to non-encapsulated PE formulation. Importantly, the hydrogel containing phytosome showed a potential for UVA and UVB radiation absorption, indicated by the SPF values of higher than 15. To conclude, this work shows promising novel delivery approaches for PE in the treatment of organ injured stress oxidative and skin aging.