Clinical Drug Experience Knowledgebase

Imidurea (Imidazolidinyl urea) is used as an antimicrobial agent and preservative in cosmetics and toiletries. It is very active against gram+ and gram- bacteria as a synergist in combination with parabens. Imidazolidinyl urea is more active against bacteria than fungi and is often combined with parabens to provide a broad spectrum preservative system. This preservative is one of the most widely used preservative systems in the world. The Food and Drug Administration (FDA) considers imidazolidinyl urea as one of the most common antimicrobial agents used in cosmetics. Due to its high water solubility, imidazolidinyl urea can be incorporated into almost all water-based cosmetics, toiletries, and cold mix formulations. It is present in a wide range of liquid and powder products such as baby lotion, skin cream, sunscreens, shampoos, eyeliners, blush, perfumes, deodorants, hair dyes, shaving cream, and face masks. Imidazolidinyl urea is permitted for use in personal care products in the European Union at a maximum concentration of 0.6%. In Japan, imidazolidinyl urea is allowed in rinse-off cosmetics such as shampoo, body wash, and facial cleanser at a maximum concentration of 0.3%. Imidurea is an ingredient of FDA-approved NIZORAL® (ketoconazole) 2% Shampoo, indicated for the treatment of tinea (pityriasis) versicolor caused by or presumed to be caused by Pityrosporum orbiculare (also known as Malassezia furfur or M. orbiculare).   ^NCATS