title: Skin protection against ultraviolet induced free radicals with ascorbyl palmitate in microemulsions.
abstract: UV irradiation induces free radical formation in the skin. UV filters and antioxidants can be used for protection. In the present work, the amphiphilic antioxidant ascorbyl palmitate has been investigated and its effectiveness against free radical formation in porcine skin determined with electron paramagnetic resonance (EPR) spectroscopy with a spin trapping technique. 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO) was used as spin trap. In this study, three different radicals were identified in UV irradiated porcine ear skin: two originated from sulphur centred radicals (SO(3)*), while the third was the carbon-centred acyl (C=O*) radical. Ascorbyl palmitate applied on the skin decreased the level of formation of free radicals. Its effectiveness depended significantly on the carrier system - the type of microemulsion and its concentration, while the time of application had no influence on its effectiveness. Oil in water microemulsions delivered ascorbyl palmitate to the skin significantly better than water in oil microemulsions. In both types of microemulsions, the effectiveness increases at higher concentrations of ascorbyl palmitate.
authors.affiliation: Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Polona
authors.initials: P
authors.lastname: Jurkovic
authors.forename: Marjeta
authors.initials: M
authors.lastname: Sentjurc
authors.forename: Mirjana
authors.initials: M
authors.lastname: Gasperlin
authors.forename: Julijana
authors.initials: J
authors.lastname: Kristl
authors.forename: Slavko
authors.initials: S
authors.lastname: Pecar
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D004339:Drug Compounding; D004655:Emulsions; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D066298:In Vitro Techniques; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D013552:Swine; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D016166:Free Radical Scavengers; D005609:Free Radicals; D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid