Biological Evaluation and Compatibility Study of Oral Mucoadhesive Hydrogel Formulations Using Schinopsis Brasiliensis Engler. Extract and Excipients

Native to Brazil, Schinopsis brasiliensis Engl. (Anacardiaceae) is the main representative species of the Schinopsis genus. It brings anti-inflammatory, analgesic, hemostatic, antiseptic, antibacterial, and antifungal properties. The aims of this study were to evaluate the antifungal potential of S. brasiliensis extract (API) against strains of Candida albicans, to perform a compatibility study with mucoadhesive excipients, to evaluate antifungal activity, and characterize a mucoadhesive hydrogel for oral use. The antifungal activity was evaluated, and a pharmacological potency assay of different concentrations of the hydroethanolic extract of the leaves of S. brasiliensis was performed using agar diffusion techniques, in a 5 × 1 cylinder design method. The compatibility study between binary mixtures (BM) of extract and excipients was performed using differential thermal analysis (DTA), thermogravimetry (TG), and Fourier transform infrared spectroscopy (FTIR). The hydrogels formulated were characterized for pH, viscosity, and mucoadhesive strength and then evaluated for antifungal activity. C. albicans was susceptible to the API at concentrations of 5, 10, 20, 40, and 80 mg mL−1. The pharmacological potency was superior than the gallic acid chemical marker, with the API concentration for the hydrogel formulation at 50 mg mL−1. The TG and DTA curves for the API—BM with carbopol (CAR) or pluronic hydrogel (PLU) maintained both the excipient and API thermal characteristics, suggesting compatibility between them. The 30% PLU hydrogel/API association presented the best performance and, considering the parameters of this study, should be further investigated as a potential oral antifungal agent with activity against C. albicans.