Comparative bio-availability and activity of proprietary topical corticosteroid preparations: vasoconstrictor assays on thirty-one ointments.

Thirty-one proprietary corticosteroid ointments were evaluated for vasoconstriction using an occluded blanching test. The results were expressed as three parameters: (1) area under the blanching curve, (2) summed % total possible score, and (3) square root transformation of sum of scores divided by number of volunteers. Experiments were performed to (a) compare the bio-availability and activity of the ointments, (b) determine the effect of antimicrobial additivies, and (c) assess the retention of steroids in the skin. Scores for the additivie-containing and 'plain' preparations were within 90% except for Locorten-Vioform/Locorten (58%). A steroid reservoir in the skin was demonstrated lasting for 8-14 days. Selected preparations were re-tested by a non-occluded method. The results for the ointments were compared with those previously obtained using the corresponding creams.