title: Determination of the formation of the stratum corneum reservoir for two different corticosteroid formulations using tape stripping combined with UV/VIS spectroscopy.
abstract: BACKGROUND
  The stratum corneum, the outermost layer of the skin, not only represents a barrier, but also a reservoir for topically applied substances. Both properties influence the penetration process, as does the vehicle. It determines the penetration pathway and the retention time of the topically applied substances.
  
  
  METHODS
  Two commercial products (Temovate Cream and Temovate Emollient), both containing 0.05% clobetasol propionate, were applied on the inner forearms of healthy volunteers. 20 tape strips were removed from each treated skin area. The horny layer profile was determined measuring the absorption of the corneocytes at 430 nm. The concentration of clobetasol propionate on the individual tapes was then analyzed.
  
  
  RESULTS
  We found differences in the reservoir formation depending on the formulation applied, which correlated to the biological response in the form of a blanching effect.
  
  
  CONCLUSIONS
  The method applied is well-suited to determine the reservoir formation in the stratum corneum for topically applied substances.
authors.affiliation: Department of Dermatology, Center of Experimental and Applied Cutaneous Physiology, University Medical Center Charité, Humboldt-University, Berlin, Germany.
authors.forename: Ragna v
authors.initials: Rv
authors.lastname: Pelchrzim
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Weigmann
authors.forename: Hans
authors.initials: H
authors.lastname: Schaefer
authors.forename: Timo
authors.initials: T
authors.lastname: Hagemeister
authors.forename: Michael
authors.initials: M
authors.lastname: Linscheid
authors.forename: Vinod P
authors.initials: VP
authors.lastname: Shah
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sterry
authors.forename: Jurgen
authors.initials: J
authors.lastname: Lademann
mesh_terms: D000287:Administration, Topical; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics; D000328:Adult; D001458:Bandages; D002990:Clobetasol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis / Q000493:pharmacokinetics; D003879:Dermatologic Agents / Q000008:administration & dosage* / Q000032:analysis / Q000493:pharmacokinetics*; D004817:Epidermis / Q000378:metabolism*; D005260:Female; D006801:Humans; D008657:Metabolic Clearance Rate; D012869:Skin Absorption / Q000502:physiology*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D000305:Adrenal Cortex Hormones; D003879:Dermatologic Agents; D002990:Clobetasol