title: Topical delivery of acetyl hexapeptide-8 from different emulsions: influence of emulsion composition and internal structure.
abstract: Acetyl hexapeptide-8 (AH-8) is a well-known component of anti-aging products and was recently explored as a promising topical treatment of blepharospasm. Although AH-8 appears in a variety of cosmetic products, its skin penetration is sparsely studied and controversially discussed. Therefore, the aim of the present study was to investigate the influence of the vehicle type on the AH-8 delivery to the skin. Besides skin permeation experiments with Franz type diffusion cells, the spatial distribution of AH-8 in the stratum corneum after a real in-use application was investigated by in vitro tape stripping on porcine ear skin. By applying LC-MS/MS for quantification of AH-8, we demonstrated that a multiple water-in-oil-in-water (W/O/W) emulsion can significantly increase penetration of AH-8 into porcine skin compared to simple O/W and W/O emulsions. The internal structure of the developed multiple emulsion was confirmed by electron microscopic investigations and NMR self diffusion studies. In general, a clear superiority of water-rich W/O/W and O/W emulsions over an oil-rich W/O emulsion in terms of dermal delivery of AH-8 was found. This enhanced delivery of AH-8 could be explained by an increased absorption of the water-rich emulsions into the skin, confirmed by combined ATR-FTIR and tape stripping experiments.
authors.affiliation: Research Platform 'Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms', University of Vienna, 1090 Vienna, Austria.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Hoppel
authors.affiliation: Department of Pharmacognosy, University of Vienna, 1090 Vienna, Austria.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Reznicek
authors.affiliation: Research Platform 'Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms', University of Vienna, 1090 Vienna, Austria; Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria.
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Kählig
authors.affiliation: Campus Science Support Facilities GmbH, Electron Microscopy Facility, 1030 Vienna, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Kotisch
authors.affiliation: Campus Science Support Facilities GmbH, Electron Microscopy Facility, 1030 Vienna, Austria; Nexperion - Solutions for Electron Microscopy, 1040 Vienna, Austria.
authors.forename: Günter P
authors.initials: GP
authors.lastname: Resch
authors.affiliation: Research Platform 'Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms', University of Vienna, 1090 Vienna, Austria; Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, 1090 Vienna, Austria. Electronic address: claudia.valenta@univie.ac.at.
authors.forename: Claudia
authors.initials: C
authors.lastname: Valenta
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D004655:Emulsions; D006027:Glycosides / Q000737:chemistry; D066298:In Vitro Techniques; D009226:Myristates / Q000737:chemistry; D009842:Oligopeptides / Q000008:administration & dosage* / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012867:Skin / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects*; D013395:Sucrose / Q000031:analogs & derivatives* / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D013552:Swine; D014280:Triglycerides / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D004655:Emulsions; D006027:Glycosides; D009226:Myristates; D009842:Oligopeptides; C000600434:PEG-30-dipolyhydroxystearate; D011091:Polyesters; D013501:Surface-Active Agents; D014280:Triglycerides; C010807:xylosides; D014867:Water; C008205:isopropyl myristate; C018153:sucrose monostearate; C022834:miglyol 812; D011092:Polyethylene Glycols; D013395:Sucrose; C582852:acetyl-glutamyl-glutamyl-methionyl-glutaminyl-arginyl-argininamide
keywords: ATR-FTIR; Acetyl hexapeptide-8; Freeze–fracture; LC–MS/MS; Multiple emulsions; NMR