Penetration of Topical Steroid Preparations

To the Editor.—  Much effort has been channeled recently into the production of topical steroid preparations with increased percutaneous penetrative capability.While a rapid release of the steroid from its vehicle is certainly useful, we believe that rapid and increased penetration of the steroid into the dermis may not be entirely desirable. This is because the site of the anti-inflammatory action of the topically applied steroid is as yet unknown.The dermal vasoconstriction resulting from topical application of a steroid preparation is generally believed to reflect its effectiveness. However, occasional discrepancies between vasoconstriction bioassay results and clinical effectiveness do exist; correlation of vasoconstriction and clinical potency has been questioned by some.¹ This suggests that, in some instances, dermal activity of the steroid does not correlate with effectiveness.The ointment base, because of its occlusive nature, allows a greater penetration by the topically applied steroid. The steroid ointment is generally