Development of a liquid crystalline gel based on Amazonian butter extracted from ucuúba seeds (Virola surinamensis (Rol. ex Robbt.) Warb.) for vaginosis treatment

This study focuses on developing a liquid crystalline gel based on ucuúba butter from the Amazon. This gel, which offers distinct technological advantages for vaginal sustained drug release systems, was characterized by polarized light microscopy (PLM), pH measurements, water uptake assay, drug release profile and kinetic study (using the Excel Add-in and DDSolver). The unloaded and drug-loaded liquid crystalline gel containing 10% metronidazole exhibited a hexagonal mesophase structurally favorable for sustained drug release, with a pH value of 6,4 ± 0.024. The water uptake profile showed a fast water uptake in up to 1 h, approximately 16%, with the maximum amount of water, 40%, in 8 h. After water uptake, the liquid crystalline gel undergoes self-assembly to a viscous cubic phase, avoiding rapid erosion in an aqueous medium. In vitro, the release of metronidazole was slow, with 52% of the drug released in 10 h. The best fit was the Higuchi kinetic model with the highest MSC (3,94) and R2 (0,98) values, indicating that the drug release was diffusion-controlled. Korsmeyer’s model showed that formulation exhibited anomalous transport (non-Fickian). Given the limited number of options for topical vaginal treatment, this liquid crystalline gel based on Virola surinamensis (Rol. ex Robbt.) Warb.) butter could potentially find applicability to reduce the frequency of administration and improve local concentrations of metronidazole on vaginal mucous.