The release of zinc ions from and cytocompatibility of two zinc oxide dressings.
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.
Agren
M S
MS
Department of Surgery K, Bispebjerg Hospital, University of Copenhagen, Denmark.
Mirastschijski
U
U
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*
D003879:Dermatologic Agents; D004338:Drug Combinations; D007477:Ions; D009824:Ointments; D010592:Pharmaceutic Aids; D011205:Povidone; D015034:Zinc Oxide