Context: Our group previously reported the photoinstability of some desonide topical commercial formulations under direct exposure to UVA radiation.
Objective: This study aimed to prepare and characterize a gel-cream containing desonide, with greater photostability than the commercial gel-cream (C-GC). Benzophenone-3 (BP-3) was used as a photostabilizing agent.
Methods: The gel-cream developed (D-GC) containing BP-3 at 0.1% was prepared and characterized regarding its pH, drug content, spreadability, viscosity, in vitro drug release and in vitro permeation. The in vivo anti-inflammatory effect was assessed by ear edema measurement, croton oil-induced acute skin inflammation and myeloperoxidase assay.
Results and discussion: D-GC presented characteristics compatible with topical application, appropriate drug content and good spreadability, and non-Newtonian behavior with pseudoplastic flow. D-GC showed a good photostability profile, presenting a desonide content of 95.70% after 48 h of exposure to UVA radiation, and stability under room conditions during 60 days. The amount of desonide released from D-GC and C-GC was 57.8 and 51.7 µg/cm2, respectively, measured using the vertical Franz cell. The in vitro skin permeation showed that desonide reached the site of action of the topical corticosteroids, from both formulations; however, the desonide amount retained in the dermis was lower with D-GC. The in vivo evaluation of topical anti-inflammatory activity indicated that D-GC presented the same biological effect as C-GC.
Conclusion: D-GC represents a promising approach to treat dermatological disorders, since it presented satisfactory physicochemical characteristics, the same biological activity as C-GC and superior photostability, conferred by the addition of BP-3 at 0.1%.
Keywords: Benzophenone-3; MPO activity; corticosteroids photostability; desonide; ear edema; photostability; skin permeation.