Abstract

Objective: The topical use of corticosteroids and vitamin D derivatives represents the first line treatment of mild or moderate plaque psoriasis. The most studied and used fixed combination of betamethasone (BMS) and calcipotriol (CAL) for the treatment of PS is available in different topical formulations, among which ointment (OIT) and cutaneous foam (CF). For topical products, the type of formulation has great impact in the pharmacokinetic behaviour of active molecules, for examples formulations like ointments, due to their occlusive action, are generally more efficient in enhancing the penetration of active compounds compared to other formulations. However few data comparing the pharmacokinetic characteristics of BMS and CAL in OIT and CF are available. The aim of this study was to evaluate and compared the characteristic of skin penetration of two commonly used topical formulations: ointment and cutaneous foam of BMF (0.5 mg/g) and CAL (50 µg/g). Methods: To evaluate the penetration potential of the active ingredients contained in the two formulations included in the study the Reconstructed Human Epidermis by Matter (RHEM) model was used. The permeability experiments were performed 4 hours after the application of equal amounts of the two tested formulations. The concentration of BMS and OIT in both acceptor and donor compartments were quantified using ELISA test. Results: The penetration of active compounds (BMS and CAL) in fixed combination vehiculated in OIT (7.6% ± 1.8% and 5.1% ± 8.6% for BMS and CAL, respectively) or in CF (7.8% ± 2.0% and 2.1% ± 4.7% for BMS and CAL, respectively) in a RHEM model resulted comparable for both the formulations. The OIT showed a slightly, although not significant, greater penetration of the CAL compounds. Conclusions: The ointment and foam formulations are superimposable, in term of penetration of active compounds through this RHEM model. This data suggested that the ointment formulation still represents a useful topical treatment for the management of mild or moderate plaque psoriasis.