THE EFFECT OF 1,24(R)(OH)(2)D-3 CREAM AND OINTMENT ON EPIDERMAL PROLIFERATION AND DIFFERENTIATION IN MICE

Background: The 1,24(R)(OH)(2)D-3 (tacalcitol) ointment (2 mu g/g) is available commercially as an antipsoriatic drug in Japan, but the crea m preparation of tacalcitol is still under development. Objective: Thi s study was conducted to compare the ability of tacalcitol cream and o intment to inhibit epidermal proliferation and induce epidermal differ entiation. Methods: We measured the ornithine decarboxylase activity a nd type I transglutaminase activity as indices of proliferation and di fferentiation, respectively, in hairless mice. Results: These effects were statistically equal to those of the ointment preparation at the s ame dose, 2 mu g/g, without inducing hypercalcemia. Conclusions: These findings suggest that topical application of 1,24(OH)(2)D-3 cream (2 mu g/g) might have the same potency as the ointment formulation in the treatment of psoriasis.