Dithranol in a cream preparation: Disperse or dissolve?

In the search for the ideal dithranol cream preparation for short-contact t reatment of psoriasis, we investigated the clinical efficacy, side effects and patient appreciation of two dithranol cream preparations (cream A and B ) in a double-blind left-right comparing study. Dithranol was dissolved at preparation in cream A and dispersed in cream B. Cream A is known to have a shelf life of 1 year, while cream B has a much shorter shelf life (several months). Ten patients with chronic plaque-type psoriasis were treated duri ng 7 weeks in a short-contact regimen. The clinical efficacy was monitored by scoring of erythema, induration, scaling and involved area (PASI); skin irritation was scored visually, and patient appreciation was evaluated by m eans of a multiple-choice questionnaire. Dispersion of dithranol in a cream was associated with less irritation and less discoloration of the skin, an d its efficacy was comparable with that of the cream in which the dithranol was dissolved. As the dispersed dithranol formulation is easier to be manu factured, its quality will be less depending on the pharmacist's experience and equipment, and so more reliable. Besides, it will be less expensive to prepare. We advise to use this formulation for short-contact treatment. Co pyright (C) 2000 S. Karger AG, Basel.