title: Fish skin as a model membrane: structure and characteristics.
abstract: OBJECTIVE
  Synthetic and cell-based membranes are frequently used during drug formulation development for the assessment of drug availability. However, most of the currently used membranes do not mimic mucosal membranes well, especially the aqueous mucous layer of the membranes. In this study we evaluated catfish (Anarichas lupus L) skin as a model membrane.
  
  
  METHODS
  Permeation of hydrocortisone, lidocaine hydrochloride, benzocaine, diethylstilbestrol, naproxen, picric acid and sodium nitrate through skin from a freshly caught catfish was determined in Franz diffusion cells.
  
  
  RESULTS
  Both lipophilic and hydrophilic molecules permeate through catfish skin via hydrated channels or aqueous pores. No correlation was observed between the octanol/water partition coefficient of the permeating molecules and their permeability coefficient through the skin. Permeation through catfish skin was found to be diffusion controlled.
  
  
  CONCLUSIONS
  The results suggest that permeation through the fish skin proceeds via a diffusion-controlled process, a process that is similar to drug permeation through the aqueous mucous layer of a mucosal membrane. In addition, the fish skin, with its collagen matrix structure, appears to possess similar properties to the eye sclera.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: Fífa
authors.initials: F
authors.lastname: Konrádsdóttir
authors.forename: Thorsteinn
authors.initials: T
authors.lastname: Loftsson
authors.forename: Sigurdur Dadi
authors.initials: SD
authors.lastname: Sigfússon
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000465:Algorithms; D000818:Animals; D001566:Benzocaine / Q000493:pharmacokinetics; D002397:Catfishes; D004054:Diethylstilbestrol / Q000493:pharmacokinetics; D004058:Diffusion; D006854:Hydrocortisone / Q000493:pharmacokinetics; D066298:In Vitro Techniques; D007700:Kinetics; D008012:Lidocaine / Q000493:pharmacokinetics; D008566:Membranes / Q000033:anatomy & histology / Q000378:metabolism*; D008954:Models, Biological; D009288:Naproxen / Q000493:pharmacokinetics; D009566:Nitrates / Q000493:pharmacokinetics; D010539:Permeability; D010851:Picrates / Q000493:pharmacokinetics; D012867:Skin / Q000033:anatomy & histology / Q000378:metabolism*; D012869:Skin Absorption; D047392:beta-Cyclodextrins / Q000493:pharmacokinetics
chemical_list: D009566:Nitrates; D010851:Picrates; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D009288:Naproxen; D004054:Diethylstilbestrol; C031618:sodium nitrate; D008012:Lidocaine; C005858:picric acid; C031215:betadex; D001566:Benzocaine; D006854:Hydrocortisone