Desonida: desenvolvimento e estudo de estabilidade de formulações de uso tópico

Abstract

Desonide is a corticoid used topically in the treatment of dermatological diseases of inflammatory or allergic origin. In Brazil, is available as cream (0.05%), creamy lotion (0.05%), gel cream (0.05%), ointment (0.05%) and hair lotion (0.1%). Recent studies demonstrated the photoinstability of some marketed formulations of desonide (hair lotion, creamy lotion and gel cream), upon direct exposure to UVA radiation. Thus, the aim of this work was to develop desonide hair solution and desonide gel cream, seeking to obtain products with higher photostability than the marketed products. Capillary solutions with similar composition to the one commercially available were prepared and they were added of excipients such as antioxidants and ultraviolet filter benzophenone-3 (BZ-3). The antioxidants used were not able to avoid desonide fotodegradation upon UVA light exposure (15h), being the residual content of desonide between 43.2 and 61.8%. The antioxidants used were not able to avoid the desonide fotodegradation when the formulations were exposed to UVA for 15 hours (residual levels between 43.2% and 61.8%). BZ-3 at 0.3% prevented desonide photolysis, since after 15 hours of exposure to direct UVA radiation, the residual content of desonide was 98.61%. The photostability of the hair solution with BZ-3 was also evaluated against UVC radiation, and their results compared to the formulation without this adjuvant. It was observed that desonide in hair solution with BZ-3 degraded slowly (t 90 1.41 h) than the formulation without BZ-3 (t90 0.64 h). The BZ-3 was also used as adjuvant in the gel cream developed, but at the concentration of 0.1%. This formulation was characterized with respect to its rheological properties, spreadability, pH, in vitro release profile and content, presenting satisfactory physicochemical characteristics and being suitable for topical application. The photostability study conducted by direct exposure to UVA radiation demonstrated the stability of the desonide gel cream, which was indicated by the residual content around 95% after 48 hours of evaluation. The stability study performed at 20°C and 40°C showed that the capillary solution formulation was stable under both conditions for 70 days. Under the same conditions, the gel cream proved to be stable at a temperature of 20°C for 60 days.