title: Buffering capacity of human skin layers: in vitro.
abstract: OBJECTIVE
  The skin possesses buffering capacity to resist acidic/alkaline aggression. Skin components contribute differently to this buffering capacity. This study investigates buffering capacity in three skin layers: intact stratum corneum (SC), epidermis and dermis.
  
  
  METHODS
  Sodium hydroxide (NaOH) and hydrochloric acid (HCl) solutions at 0.025, 0.05 and 0.1 N were applied to skin (3.18 μL/cm(2)). After 30 min, the skin was washed with 1 mL de-ionized water. TEWL and pH measurements were conducted at baseline (before contact with acid or base), 0, 10 and 30 min post exposure, and continued at 0, 10 and 30 min post washing.
  
  
  RESULTS
  Data indicate that immediately following acid or base exposures, the dermis demonstrates the highest buffering capacity, while with time, intact stratum corneum predominates.
  
  
  CONCLUSIONS
  These findings potentiate advanced understanding of skin's buffering capacity as related to dermatopharmacology and dermatotoxicology.
authors.affiliation: Department of Dermato-Venereology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zheng
authors.forename: Bahman
authors.initials: B
authors.lastname: Sotoodian
authors.forename: Wei
authors.initials: W
authors.lastname: Lai
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000136:Acid-Base Equilibrium; D000368:Aged; D005260:Female; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000737:chemistry* / Q000166:cytology*; D012972:Sodium Hydroxide / Q000737:chemistry*
chemical_list: D012972:Sodium Hydroxide; D006851:Hydrochloric Acid