title: Proposed human stratum corneum water domain in chemical absorption.
abstract: Compounds with varying physical and chemical properties may have different affinities to the stratum corneum (SC) and/or its intercellular lipids, keratin protein, and possible water domains. To better understand the mechanism of percutaneous absorption, we utilized 21 carbon-14 labeled chemicals, with wide hydrophilicity (log P = -0.05 to 6.17), and quantified their absorption/adsorption properties for a short incubation time (15 min) with regards to intact SC membrane, delipidized SC membrane and SC lipid. A facile method was developed for SC/lipid absorption, providing a more equivalent procedure and comparable data. SC lipid absorption of chemical solutes positively correlated with the octanol/water partition coefficient (log P). Differences between the percent dose of chemical absorption to intact SC and the total percent dose contributed by the protein and lipid domains suggest the possibility and significance of a water domain. Absorption rate experiments showed a longer lag time for intact SC than for delipidized SC or SC lipid, suggesting that the water domain may delay chemical binding to protein and lipid domains, and may be a factor in the resistance of many chemicals to current decontamination methods. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Department of Dermatology, University of California, San Francisco, CA, 94143-0989, USA.
authors.forename: Hanjiang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Dermatology, University of California, San Francisco, CA, 94143-0989, USA.
authors.forename: Eui-Chang
authors.initials: EC
authors.lastname: Jung
authors.affiliation: Department of Dermatology, University of California, San Francisco, CA, 94143-0989, USA.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Hui
authors.affiliation: Department of Dermatology, University of California, San Francisco, CA, 94143-0989, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Maibach
mesh_terms: D000328:Adult; D002250:Carbon Radioisotopes / Q000737:chemistry; D055598:Chemical Phenomena; D003666:Decontamination; D004817:Epidermis / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007633:Keratins / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008954:Models, Biological; D012869:Skin Absorption; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D002250:Carbon Radioisotopes; D008055:Lipids; D012996:Solutions; D014867:Water; D007633:Keratins
keywords: lipid domain; percutaneous absorption / decontamination; protein binding; skin reservoir effect; stratum corneum; water domain