Enhancement of trans-resveratrol photostability by encapsulation in lipid microparticles: in vitro and in vivo studies

Lipid microparticles (LMs) loaded with the antioxidant polyphenol, trans-resveratrol were developed in order to enhance its photostability in topical formulations. The LMs were prepared by the melt emulsification technique, using tristearin as the lipidic material and hydrogenated phosphatidylcholine as the surfactant. The obtained microparticles were characterized by optical microscopy and release studies. The trans-resveratrol loading was 10.8% (w/w). Free or microencapsulated trans-resveratrol was introduced in model topical formulations (cream and hydrogel) and irradiated with a solar simulator. The light-induced degradation of trans-resveratrol was significantly reduced by incorporation into the LMs both in the cream (the trans-resveratrol loss decreased from 34.3% to 19.9%) and in the hydrogel (the trans-resveratrol decomposition decreased from 15.4% to 9.4%) vehicles. Moreover, the in vitro (i.e., antioxidant action) and in vivo (i.e., anti-inflammatory action) biological activities of trans-resveratrol in the cream preparation were not altered by the encapsulation process