Control of the bioavailability of a topical steroid; comparison of desonide creams 0.05% and 0.1% by vasoconstrictor studies and clinical trials.

Summary Theoretically two corticosteroid preparations should show the same clinical activity even though they possess different medicament concentrations, provided that both preparations are at or above saturation e.g. they are suspensions. To test this theory, the non-fluorinated corticosteroid desonide prepared as two suspensions in the same cream formulation (Apolar Cream 0.1% and 0.05%) were evaluated for vasoconstriction using an occluded blanching test. Included in the vasoconstriction test were also another desonide 0.05% preparation (Tridesilon Cream®) and Betnovate Cream® (betamethasone 17-valerate 0.1%). The study was extended into patients by comparing the effects of Apolar Cream 0.1% and 0.05, in a double-blind, randomized, right-left comparative study including 40 patients with bilateral, non-infected hand eczemas, No significant difference could be demonstrated between the blanching responses of the four preparations tested in the vasoconstriction study. Betnovate Cream provided the lowest blanching response. Thirty-eight patients completed the clinical trial. All patients improved after 11 days of treatment with Apolar Cream 0.1%. With the 0.05% cream, 37 improved and, in one, the condition remained unchanged. No statistically significant difference could be demonstrated between treatments. It is concluded that, for practical therapeutic purposes, Apolar Cream 0.05% will equate with the corresponding 0.1% preparation.