title: Correlation of transepidermal water loss with skin barrier properties in vitro: comparison of three evaporimeters.
abstract: OBJECTIVE
  This study investigates the relationship between transepidermal water loss (TEWL) and skin permeability to tritiated water as a rapid assessment of the integrity of the barrier properties of skin as part of in vitro skin permeation studies.
  
  
  METHODS
  TEWL values before and during the experimental period were measured using three evaporimeters (A, B, and C) representing different measuring principles and technologies. Single application of tritiated water was dosed on dermatomed human skin samples in a flow-through diffusion cell system. Radioactivity of the absorbed dose and the removable dose residues was counted to determine percent dose and flux rate. These data were further combined with TEWL values to analyze the correlation.
  
  
  RESULTS
  Evaporimeter C, a closed chamber-condenser technology, had higher measurement capacity than other instruments, evaporimeter A, an open chamber, and evaporimeter B, a closed chamber (P<0.001). The baseline TEWL value correlated with tritiated water flux (r=0.34, P=0.04). The pattern of tritiated water expressed as percent dose permeated into receptor fluid was similar to that of TEWL values.
  
  
  CONCLUSIONS
  These data indicate that TEWL can be ascribed to be a measure of skin water barrier function. Further work should be conducted to interpret the significance of measuring TEWL by evaporimetry.
authors.affiliation: Department of Dermatology, School of Medicine, University of California, San Francisco, CA 9414-0989, USA. relkeeb@yahoo.com
authors.forename: Rania
authors.initials: R
authors.lastname: Elkeeb
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Hui
authors.forename: Heidi
authors.initials: H
authors.lastname: Chan
authors.forename: Lilian
authors.initials: L
authors.lastname: Tian
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000328:Adult; D000368:Aged; D004817:Epidermis / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D011877:Radionuclide Imaging; D012869:Skin Absorption / Q000502:physiology*; D012881:Skin Temperature / Q000502:physiology; D014316:Tritium; D014867:Water / Q000032:analysis / Q000378:metabolism*; D014870:Water Loss, Insensible / Q000502:physiology*; D055815:Young Adult
chemical_list: D014867:Water; D014316:Tritium