Semisolid formulations containing cetirizine: human skin permeation and topical antihistaminic evaluation in a rabbit model

Cetirizine dihydrochloride (CTZ) is a second-generation histamine H-1 antagonist, effective for the treatment of a wide range of allergic diseases. It has been utilized for managing the symptoms of chronic urticaria and atopic skin conditions. Thus, two novel semisolid formulations, nanoemulsion (NE) and hydrogel (HG) were developed to study their potential utility as vehicles including cetirizine (CTZ) and evaluate the potential use as topical H-1-antihistamines agents. The physicochemical and stability properties of both vehicles were tested. Drug release kinetics and human skin permeation studies were performed using Franz cells. The antihistaminic activity was assayed in New Zealand rabbits and compared with two commercial first generation antihistamines. Both formulations were stable and provided a sustained drug release. Amounts of CTZ remaining in the skin were higher for HG, showing the maximum biological effect at 30 min, similar to topical first generation H-1-antihistamines commercially available. These results suggest that CTZ-HG could be a promising system for the treatment of topical allergy bringing rapid antihistaminic relief.