New solid ketoconazole: salicylic acid development, characterization and evaluation antibiofilms

Rosario

Congreso; 7ma Reunión Internacional de Ciencias Farmacéuticas; 2023

Universidad Nacional de Rosario

Abstract: Invasive fungal infections caused by Candida spp. are a major cause of morbidity and mortality, especially in immunocompromised and critically ill patients. The progressive increase in antimicrobial drug resistance, combined with the ability of fungi to form biofilms, complicates this situation. Moreover, it represents an additional challenge for the effective treatment of Candida spp. infections.A promising strategy to overcome this challenge is the development of drug combinations containing one compound with known antifungal action and another compound that has reported antifungal capacity.Ketoconazole (KTZ) is a synthetic imidazole antifungal agent widely used to treat fungal infections, characterized by its low aqueous solubility. Salicylic acid (SA), which is used in skin care products, has been shown to have activity against Candida spp.In this context, the preparation and characterization of systems combining KTZ and SA in an equimolar ratio (1:1) were carried out. In addition, the solubility of this system and its antibiofilm activity compared to pure KTZ were determined.The new KTZ:SA solids in a 1:1 molar ratio were obtained by melting and physical mixing (PM) of the components. They were characterized by infrared spectroscopy (FTIR), hot-stage microscopy (HSM), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The saturation solubility of systems was determined by equilibrating excess powder in water for 72 h on a mechanical shaker at 37 °C. The minimum inhibitory concentration (MIC) was determined by the microdilution method according to the Clinical Laboratory Standards Institute (CLSI). The antibiofilm activity was determined by the MTT assay and by confocal laser scanning microscopy (CLSM) against clinical strains of C. albicans and C. tropicalis.The melting process produced a solid with a red color. FTIR analysis suggests ionic drug-drug interactions, and PXRD studies evidence the amorphous state of the solid formed. The solid has a glass transition temperature of 70 °C, according to HSM analysis, while TGA studies show that the system´s thermal degradation begins at 186°C. There was a 520-fold increase in solubility compared to pure KTZ. Further, KTZ:SA showed a decrease in biofilm formation in the clinical strains of C. albicans and C. tropicalis compared to pure KTC. These results were contrasted in C. tropicalis by the CLMS studies: pure KTZ only alters fungal cell morphology, whereas KTZ:SA alters morphology and reduces notably the number and density of cells per field.In conclusion, a new solid KTZ:SA system was obtained, and it was characterized as a promising combination against a form of resistance to antimicrobials, such as biofilm formation.