Bactericidal activity and toxicity of iodine-containing solutions in wounds

Complexing iodine with povidone (polyvinylpyrrolidone) or surfactants significantly limits the quantity of free iodine. Reduction of the free iodine level eliminates the adverse properties of staining, instability, and irritation and also alters bactericidal activity. Addition of detergents to create surgical scrub solutions further reduces the activity of iodine. In vitro testing indicated that the bactericidal activity of iodophors was inferior to that of uncomplexed aqueous iodine. In vivo tests proved that aqueous iodine significantly potentiated the development of infection. Although the povidone iodophor did not enhance the rate of wound or infection, it offered no therapeutic benefit when compared with control wounds treated with saline solution. Addition of detergents to the povidone iodophor was deleterious, with the wounds exposed to this combination displaying significantly higher infection rates than untreated control wounds. Based on these results, aqueous iodine solutions and iodophor surgical scrub solutions should not be used on broken skin. Aqueous iodophors can be used in wounds, but no therapeutic benefit from such use was found in this study.