Characteristics of chelation ability of chosen metal ions by protective ointments containing Na2H2EDTA.

Allergy contact dermatitis is a common occupational disease and the protective ointments are often used by the sensitized subjects. The efficacy of the chelation ability of the barrier creams containing Na2H2EDTA was evaluated. The in vitro test with the diffusion chamber and artificial membrane was performed. The effect of the Na2H2EDTA concentration (3, 5 or 10%), pH of the buffer for Na2H2EDTA dissolving and the vehicle of the ointment on the chelation of Ni2+ and Co2+ were assessed. The ointment with 10% Na2H2EDTA dissolved in the buffer of pH 7.0 or 7.4 buffer was found as optimal for the protection ability. There was no influence of the formula of the ointements on the efficiency of chelation.