Activity of a triamcinolone acetonide/laurocapram formulation: Double-blind comparisons with triamcinolone acetonide, placebo vehicle, and mid-strength (Class IV) to potent (Class II) corticosteroids

Background: The activity of corticosteroids is dependent on their ability t o penetrate the skin. Laurocapram is a skin penetration enhancer that facil itates absorption of cutaneously applied substances. Objective: The purpose of these studies was to determine whether the additi on of laurocapram to a topical triamcinolone acetonide CTA) 0.05% cream for mulation would improve the rate of percutaneous penetration and hence the a ctivity of the corticosteroid, as measured by increased vasoconstriction ti e, skin blanching). Methods: Thirty healthy subjects participated in each of 2 double-blind, ra ndomized, multiple-point vasoconstriction studies comparing the TA 0.05%/ l aurocapram (TNX) formulation with the placebo vehicle (TNX without TA), the TNX formulation without laurocapram (TN), and 3 mid-strength to potent cor ticosteroid formulations (fluocinolone acetonide 0.025% ointment, betametha sone dipropionate 0.05% cream, and fluocinonide 0.05% cream). Duplicate sit es on subjects' forearms were exposed to -10 mg of each formulation for 4 o r 6 hours. Sites were washed and evaluated 1 hour later (ie, 5 or 7 hours a fter application). Skin blanching activity, a surrogate marker of clinical activity and the rate of percutaneous penetration, was assessed 12 times ov er a 57-hour period using a 4-point scale (0 = none; 1 = mild; 2 = moderate ; 3 = marked). Results: In the first study, the vasoconstriction effect of the TNX formula tion after 4 hours of exposure to the cream was significantly greater than that of TN (P < 0.01). In the second study, after 6 hours of exposure, the skin blanching activity of TNX was significantly greater (P = 0.05) than th at of fluocinolone acetonide 0.025% ointment, a mid-strength corticosteroid , and betamethasone dipropionate 0.05% cream, a potent corticosteroid, and slightly less than that of fluocinonide 0.05% cream, also classified as a p otent corticosteroid. Conclusions: Based on the correlation between the vasoconstrictor activity of corticosteroids and their clinical activity, the results suggest that th e addition of laurocapram enhances the skin penetration of, and hence the a ctivity of, topical corticosteroids and may improve treatments for corticos teroid-responsive dermatoses.