title: Validation of the combined ATR-FTIR/tape stripping technique for monitoring the distribution of surfactants in the stratum corneum.
abstract: The physical presence of surfactants in the skin is linked to their skin irritation potential. Combined ATR-FTIR spectroscopy and tape stripping experiments in vitro on porcine ear skin were used to investigate the spatial distribution of sodium lauryl ether sulfate (SLES) in the stratum corneum and to assess its effects on conformational order of stratum corneum intercellular lipids, secondary structure of keratin and skin hydration. It was possible to monitor the spatial distribution of SLES in the stratum corneum for the first time by subtracting spectra of untreated from treated skin samples and without the need of a perdeuterated form. This method of analysis was evaluated by addressing potential error sources such as differences in removed amounts of corneocytes and intra-individual changes in stratum corneum composition as a function of depth. The obtained results indicate a penetration of SLES into deep layers of the stratum corneum. Furthermore, SLES treatment led to significantly decreased skin hydration levels, whereas the secondary structure of keratin remained nearly unaffected. The reliability of this semi-quantitative method of analysis was confirmed by receiving a coefficient of determination of 0.9963 after making a correlation of deep depended absorbances of two different characteristic bands with different absorption coefficients.
authors.affiliation: University of Vienna, Research Platform, Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms, Althanstraße 14, Vienna 1090, Austria.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Hoppel
authors.affiliation: University of Vienna, Department of Physical Chemistry, Faculty of Chemistry, Währingerstraße 42, Vienna 1090, Austria.
authors.forename: Dieter
authors.initials: D
authors.lastname: Baurecht
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, Althanstraße 14, Vienna 1090, Austria.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Holper
authors.affiliation: University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, Althanstraße 14, Vienna 1090, Austria.
authors.forename: Denise
authors.initials: D
authors.lastname: Mahrhauser
authors.affiliation: University of Vienna, Research Platform, Characterisation of Drug Delivery Systems on Skin and Investigations of Involved Mechanisms, Althanstraße 14, Vienna 1090, Austria; University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, Althanstraße 14, Vienna 1090, Austria. Electronic address: claudia.valenta@univie.ac.at.
authors.forename: Claudia
authors.initials: C
authors.lastname: Valenta
mesh_terms: D000818:Animals; D004817:Epidermis / Q000378:metabolism*; D066298:In Vitro Techniques; D007633:Keratins / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D015203:Reproducibility of Results; D012869:Skin Absorption; D012967:Sodium Dodecyl Sulfate / Q000031:analogs & derivatives* / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013501:Surface-Active Agents / Q000494:pharmacology*; D053832:Surgical Tape; D013552:Swine
chemical_list: D008055:Lipids; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D007633:Keratins; C408148:sodium laureth sulfate
keywords: ATR-FTIR; Skin hydration; Skin penetration; Sodium lauryl ether sulfate (SLES); Tape stripping