title: A novel approach to modelling water transport and drug diffusion through the stratum corneum.
abstract: BACKGROUND
  The potential of using skin as an alternative path for systemically administering active drugs has attracted considerable interest, since the creation of novel drugs capable of diffusing through the skin would provide a great step towards easily applicable -and more humane- therapeutic solutions. However, for drugs to be able to diffuse, they necessarily have to cross a permeability barrier: the stratum corneum (SC), the uppermost set of skin layers. The precise mechanism by which drugs penetrate the skin is generally thought to be diffusion of molecules through this set of layers following a "tortuous pathway" around corneocytes, i.e. impermeable dead cells.
  
  
  RESULTS
  In this work, we simulate water transport and drug diffusion using a three-dimensional porous media model. Our numerical simulations show that diffusion takes place through the SC regardless of the direction and magnitude of the fluid pressure gradient, while the magnitude of the concentrations calculated are consistent with experimental studies.
  
  
  CONCLUSIONS
  Our results support the possibility for designing arbitrary drugs capable of diffusing through the skin, the time-delivery of which is solely restricted by their diffusion and solubility properties.
authors: Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland. tatiana.marquez@bsse.ethz.ch
authors: Tatiana T
authors: TT
authors: Marquez-Lago
authors: Diana M
authors: DM
authors: Allen
authors: Jenifer
authors: J
authors: Thewalt
mesh_terms: D001692:Biological Transport; D004058:Diffusion; D005110:Extracellular Space / Q000378:metabolism; D008954:Models, Biological; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D016062:Porosity; D011312:Pressure; D012212:Rheology; D012867:Skin / Q000166:cytology / Q000378:metabolism*; D012869:Skin Absorption / Q000502:physiology*; D013997:Time Factors; D014867:Water / Q000378:metabolism*
chemical_list: D004364:Pharmaceutical Preparations; D014867:Water