Release and absorption of zinc from zinc oxide and zinc sulfate in open wounds.

The pharmacokinetic behaviours of zinc oxide and zinc sulfate when applied as single doses to full-thickness excised rat skin wounds were studied. In the zinc oxide group, the wound fluid zinc concentration increased slightly over the 48-h postoperative period due to increased solubilization of zinc oxide, attributed to increased protein concentration of the wound fluid. When zinc sulfate was applied to the wounds, the wound fluid zinc concentration decreased rapidly during the first 4 postoperative h and then at a slower rate. The changes in the serum zinc level followed essentially the same kinetic pattern as that of the wound fluid zinc levels. The zinc concentration of the wounded tissue remained almost constant in zinc oxide treated wounds whilst it diminished in zinc sulfate treated wounds. In conclusion, zinc oxide delivers zinc ions to wounds over an extended period of time which results in constant wound tissue zinc levels. In contrast, zinc sulfate rapidly delivers zinc ions which results in decreasing tissue zinc levels.