title: The effect of region of application on absorption of ethanol and hexanol through canine skin.
abstract: The effect of region of application on the percutaneous penetration of solutes with differing lipophilicity was investigated in canine skin. Skin from the thorax, neck, back, groin, and axilla regions was harvested from Greyhound dogs and placed in Franz-type diffusion cells. Radiolabelled (14C) ethanol (Log P 0.19) or hexanol (Log P 1.94) was applied to each skin section for a total of 5h. The permeability coefficient (kP, cm h(-1)) and residue of alcohol remaining in the skin were significantly (P=0.001) higher for hexanol compared to ethanol. In contrast, ethanol had a far greater maximum flux (Jmax, mol (cm2)(-1) h(-1)) than hexanol (P=0.001). A comparison of regional differences shows the kP and Jmax for ethanol in the groin was significantly lower (P=0.035) than the back. The kP and Jmax for hexanol were significantly higher (P=0.001) in the axilla than the other four skin sites. An understanding of factors influencing percutaneous drug movement is important when formulating topical preparations for the dog.
authors.affiliation: School of Veterinary Science, University of Queensland, Brisbane, Qld 4072, Australia. p.mills@uq.edu.au
authors.forename: P C
authors.initials: PC
authors.lastname: Mills
authors.forename: B M
authors.initials: BM
authors.lastname: Magnusson
authors.forename: S E
authors.initials: SE
authors.lastname: Cross
mesh_terms: D000818:Animals; D001365:Axilla; D001415:Back; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D004285:Dogs; D000431:Ethanol / Q000493:pharmacokinetics*; D000441:Hexanols / Q000493:pharmacokinetics*; D007700:Kinetics; D009333:Neck; D012869:Skin Absorption / Q000502:physiology*; D013909:Thorax
chemical_list: D002250:Carbon Radioisotopes; D000441:Hexanols; D000431:Ethanol