title: Imaging the distribution of sodium dodecyl sulfate in skin by confocal Raman and infrared microspectroscopy.
abstract: OBJECTIVE
  To image SDS distribution across different skin regions, to compare the permeability difference between porcine and human skin, and to evaluate the interaction between SDS and skin.
  
  
  METHODS
  Full thickness porcine and human skin was treated with acyl chain perdeuterated SDS (SDS-d(25)) at room temperature and at 34 °C for 3, 24 and 40 h. SDS distribution in skin was monitored by confocal Raman and IR microspectroscopic imaging. Permeation profiles of SDS-d(25) in skin were derived from the band intensities of the CD(2) stretching vibrations. The interaction between SDS and skin was monitored through the CH(2) and CD(2) stretching frequencies and the Amide I and II spectral region.
  
  
  RESULTS
  SDS-d(25) penetrates both porcine and human skin in a time and temperature-dependent manner, with slightly higher permeability through the stratum corneum (SC) in porcine skin. When SDS permeates into the SC, its chains are more ordered compared to SDS micelles. The secondary structure of keratin in the SC is not affected by SDS-d(25).
  
  
  CONCLUSIONS
  The spatial distribution of SDS-d(25) in skin was obtained for the first time. Infrared microscopic imaging provides unique opportunities to measure concentration profiles of exogenous materials in skin and offers insights to interaction between permeants and skin.
authors.affiliation: Johnson & Johnson Consumer Companies, Inc., 199 Grandview Rd., Skillman, New Jersey 08558-9418, USA. gmao@its.jnj.com
authors.forename: G
authors.initials: G
authors.lastname: Mao
authors.forename: C R
authors.initials: CR
authors.lastname: Flach
authors.forename: R
authors.initials: R
authors.lastname: Mendelsohn
authors.forename: R M
authors.initials: RM
authors.lastname: Walters
mesh_terms: D000818:Animals; D006801:Humans; D007633:Keratins / Q000737:chemistry; D017433:Protein Structure, Secondary; D012867:Skin / Q000737:chemistry / Q000378:metabolism*; D012869:Skin Absorption; D012967:Sodium Dodecyl Sulfate / Q000032:analysis* / Q000378:metabolism*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013501:Surface-Active Agents / Q000032:analysis* / Q000378:metabolism*; D013552:Swine
chemical_list: D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D007633:Keratins