[The suitability of propylene glycol (1,2-propanediol) as an active antimicrobial adjuvant in ointments]

Propylene glycol was tested for its antimicrobial activity as well as its possible irritant effect in ointments. With regard to the antimicrobial effect, vehicles containing more than 5% propylene glycol proved to be superior to those containing glycerol. 269 volunteers with or without eczema who had been treated with 10% propylene glycol under occlusion and by means of the Duhring chamber method, showed very few irritations; there was almost none observed in patients tested with an ointment containing glycerol instead. We did not find any allergic sensitization against propylene glycol.