The influence of urea on the penetration kinetics of topically applied corticosteroids.

The effect of urea on the penetration of hydrocortisone and triamcinolone acetonide into human skin from topically applied vehicles was studied. The resulting penetration promotion has two possible applications in topical therapy: (a) An increased therapeutic effect for a given concentration of the active constituent. (b) A given therapeutic effect could be obtained with a reduced concentration of the active ingredient.