title: Confocal Raman microspectroscopy for evaluating the stratum corneum removal by 3 standard methods.
abstract: OBJECTIVE
  Stratum corneum (SC) removal is needed in biopharmaceutical studies or in evaluating the barrier function. The most common technique is the tape stripping method. However, it results in neither a homogeneous nor a complete removal.
  
  
  METHODS
  The removal qualities of tape stripping, cyanoacrylate skin surface biopsy and trypsinization were estimated in vitro via histological imaging and confocal Raman microspectroscopy (CRM) and compared. In addition, the potential of the noninvasive CRM as a replacement method is discussed.
  
  
  RESULTS
  Comparison between the 3 methods showed, as expected, that the tape stripping method did not result in a uniform removal over the whole surface even after 28 strips. The trypsinization and cyanoacrylate skin surface biopsies allowed a complete and uniform removal of the SC after defining a standard protocol (2 cyanoacrylate strips with a polymerization time of 15 min).
  
  
  CONCLUSIONS
  The feasibility of CRM to control SC removal was demonstrated in vitro. Tape stripping is a simple method, but it is influenced by many extrinsic factors and axial drug quantification is difficult. With trypsinization and cyanoacrylate methods, the entire SC is removed so that quantification over the whole SC is possible but not an axial drug screening.
authors.affiliation: Gattefossé SAS, Saint Priest, France. forster @ lagep.cpe.fr
authors.forename: M
authors.initials: M
authors.lastname: Förster
authors.forename: M A
authors.initials: MA
authors.lastname: Bolzinger
authors.forename: M R
authors.initials: MR
authors.lastname: Rovere
authors.forename: O
authors.initials: O
authors.lastname: Damour
authors.forename: G
authors.initials: G
authors.lastname: Montagnac
authors.forename: S
authors.initials: S
authors.lastname: Briançon
mesh_terms: D000269:Adhesives; D000818:Animals; D001706:Biopsy / Q000379:methods; D003487:Cyanoacrylates; D018613:Microscopy, Confocal; D012867:Skin / Q000737:chemistry* / Q000166:cytology; D013048:Specimen Handling / Q000379:methods*; D013059:Spectrum Analysis, Raman; D013552:Swine; D014357:Trypsin; D014867:Water / Q000032:analysis*
chemical_list: D000269:Adhesives; D003487:Cyanoacrylates; D014867:Water; D014357:Trypsin