title: The release of zinc ions from and cytocompatibility of two zinc oxide dressings.
abstract: OBJECTIVE
  These in vitro studies examined the release of zinc ions from and the response of human dermal fibroblasts to two zinc oxide-medicated dressings: one with zinc oxide in an ointment base and one using polyvinylpyrrolidone (PVP), a hydrophilic polymer for the binding of zinc oxide particles.
  
  
  METHODS
  Zinc release from the dressings in buffered-saline (pH 7.4) was studied through a high-pore-density membrane (pore size, 0.40 microm) in a two-compartment model at 37 degrees C for three hours. Cytocompatibility of the dressings and 500 micromol/l of zinc ions was assessed using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay after exposure to monolayers of confluent normal human dermal fibroblasts to the dressing extracts for four hours.
  
  
  RESULTS
  The zinc release rate from PVP-bound zinc oxide was more than two-fold higher than from zinc oxide in the ointment. Extract of the zinc oxide ointment, containing 150 micromol/l solubilised zinc, elicited a cytotoxic reaction, while the zinc oxide-PVP extract, containing 410 micromol/l solubilised zinc, and 500 micromol/l zinc chloride were non-cytotoxic to the fibroblasts.
  
  
  CONCLUSIONS
  Zinc release in a simulated wound milieu appears to be inhibited when zinc oxide is incorporated in a lipophilic vehicle. It is hypothesised that the ointment vehicle induced cytotoxicity rather then the solubilised zinc oxide.
  
  
  BACKGROUND
  None.
authors.affiliation: Department of Surgery K, Bispebjerg Hospital, University of Copenhagen, Denmark.
authors.forename: M S
authors.initials: MS
authors.lastname: Agren
authors.forename: U
authors.initials: U
authors.lastname: Mirastschijski
mesh_terms: D000279:Administration, Cutaneous; D001458:Bandages / Q000592:standards*; D002626:Chemistry, Pharmaceutical; D003879:Dermatologic Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D004338:Drug Combinations; D004353:Drug Evaluation, Preclinical; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D007477:Ions; D008422:Materials Testing; D009824:Ointments; D010592:Pharmaceutic Aids / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D016062:Porosity; D011205:Povidone / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D012867:Skin / Q000166:cytology*; D012869:Skin Absorption / Q000187:drug effects*; D012995:Solubility; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D003879:Dermatologic Agents; D004338:Drug Combinations; D007477:Ions; D009824:Ointments; D010592:Pharmaceutic Aids; D011205:Povidone; D015034:Zinc Oxide