ABSTRACT
The stability of pharmaceuticals is influenced by several factors, directly related to the product, or to environmental factors, such as the presence of light and oxygen. Ketoconazole is an antifungal drug of the azole class that is prone to degradation processes, such as oxidation and hydrolysis, changing from white to pink, suggesting the formation of degradation products. Capuchin (Tropaeolum majus L.) is a species of pharmacological interest due to its phytochemical composition; it is rich in vitamin C and flavonoids with known antioxidant activity. The objective of this work was to investigate the antioxidant activity of capuchin hydroethanolic extracts and evaluate their influence on the stability of ketoconazole. For the evaluation of the antioxidant activity of the extracts, the DPPH radical was used. Different ketoconazole gel formulations were manipulated and subjected to a stability study to compare the antioxidant efficiency of the extract and sodium metabisulphite by analyzing the samples by ultraviolet scanning. Microbiological assays were performed to evaluate the activity of ketoconazole against the fungus Candida albicans. The extract solution presented antioxidant activity equivalent to a 12.71 µg/mL metabisulfite solution, and a 0.085 µg metabisulfite/µg extract ratio was calculated. In the spectrophotometric analysis, it was observed that the absorption spectrum of the extract-containing formulation presented differently from the others, with a possible advantage in relation to the synthetic antioxidant. In the microbiological analysis, only the samples that remained at room temperature formed an inhibition halo. Thus, the potential of a natural active was evaluated, representing a possible alternative for application in pharmaceutical formulations.