title: On the origin of size-dependent tortuosity for permeation of hydrophilic solutes across the stratum corneum.
abstract: Due to their low skin permeabilities, transdermal transport of hydrophilic solutes is poorly understood. In this study, we sought to determine the dependence of solute tortuosity on solute size and stratum corneum (SC) porosity. With porous pathway model, transdermal transport of hydrophilic solutes through the SC was modeled as diffusion through imperfections/defects that occur between/within the lipid lamellar organization of the SC. In order to seek an analytical solution, we assumed that the pores in the SC were cylindrical and organized in a cubical pattern. The proposed theoretical model describing the dependence of solute tortuosity on solute size and SC porosity is in agreement with prior experimentally derived tortuosity values.
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Tezel
authors.forename: Samir
authors.initials: S
authors.lastname: Mitragotri
mesh_terms: D004848:Epithelium / Q000378:metabolism*; D008954:Models, Biological; D010539:Permeability / Q000187:drug effects; D004364:Pharmaceutical Preparations / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004364:Pharmaceutical Preparations