Assessment of Topical Corticosteroid Activity Using the Vasoconstriction Assay in Healthy Volunteers

Objective and Design: The aim of the study was to evaluate the vasoconstrictive activity of four new galenic preparations of hydrocortisone and to compare it with concentration-equivalent reference preparations. The study comprised two study phases: the pilot study phase and the main study phase. During open, nonrandomized pilot study, the optimal administration period was tested. The main study was performed in a randomized, double-blind intraindividual comparative design. Subjects: Twenty male and female volunteers with healthy skin who responded to topically applied clobetasol-17-propionate before entering the trial participated in this study. Treatment: All subjects received the same treatments. The test preparations new galenic formulation (NGF) hydrocortisone 0.25% cream, NGF hydrocortisone acetate 0.25% cream, NGF hydrocortisone 0.5% cream, and NGF hydrocortisone 1.0% cream were compared with the respective reference preparations Soventol® hydrocortisone (hydrocortisone acetate 0.25%), Hydroderm HC 0.5% cream (hydrocortisone 0.5%), Hydrogalen® cream (hydrocortisone 1.0%) and placebo (vehicle of test preparations). Method: The topical preparations were applied occlusively for 2 h (pilot study) or 24 h (main study) on outlined areas (5 × 5 cm with a distance of 3 cm) of both forearms (4 areas for each). Assessment of vasoconstriction was performed before treatment, and 0.5, 4, 6 and 24 h after treatment (observation period) using a subjective rating scale (OLSEN vasoconstriction score) and measuring the colorimetric parameter a* (redness) by use of the Chroma-Meter (Minolta company, Ahrensburg, Germany). Results: A significant vasoconstriction (positive blanching effect) was measured by use of chromametry for test preparations hydrocortisone 0.25% cream, hydrocortisone 0.5% cream, hydrocortisone 1.0% cream and for the reference preparation Hydrogalen cream compared to placebo 30 min after the end of treatment. In contrast, the reference preparations Soventol hydrocortisone and Hydroderm HC 0.5% did not differ significantly from placebo 30 min after treatment. No statistically significant effect of all formulations was observed 4–24 h after treatment in comparison with placebo. Conclusions: The vasoconstrictive efficacy of test preparations was mostly stronger than the concentration-equivalent reference preparations. This effect was achieved by use of new galenics of test preparations resulting in enhanced skin penetration and improved efficiency. No u