In vitro skin permeation of paromomycin from topical formulations across normal and stripped hairless mouse skin

Petrolatum ointments containing paromomycin (PA), a highly hydrophilic antibiotic, have been used for topical treatment of cutaneous leishmaniasis. Although it is well established that the vehicle greatly influences percutaneous absorption, this aspect has not been experimentally investigated for the topical application of PA. The aim of this study is to investigate the influence of the formulation (o/w cream and ointment) on in vitro skin permeation of PA. The permeation experiments were performed in intact or stripped hairless mouse skin. Skin permeation of PA through intact skin was low for both formulations. When the entire stratum corneum was removed, PA absorption increased 52 times in comparison to that observed with hydrophilic cream on intact skin while only a small increase (less than or equal to2 times) was observed for petrolatum ointment. In this situation, PA absorption from hydrophilic formulations (cream or gel) was remarkably greater (similar to 25 times) than that observed for the petrolatum ointment.