Development and characterization of a novel nystatin-loaded nanoemulsion for the buccal treatment of candidosis: ultrastructural effects and release studies.

Oral candidosis is a common opportunistic infection in patients suffering from mucositis (after chemotherapy and radiotherapy administration) and must be treated to prevent infecting other tissue. Nystatin (Nys) is one of the most prescribed drugs to treat this pathology, but because of its physicochemical properties, its pharmaceutical-technological requirements make it a challenge. The purpose of this work was the development and characterization of an optimal Nys delivery system for the potential treatment of oral candidosis avoiding undesirable side effects and toxicity of potential systemic absorption. A nanoemulsion was developed, evaluated, and characterized. It has been formulated successfully as a stable nanoemulsion with a droplet size of 138 nm. Release parameters were estimated using different mathematical approaches, and from the results of ex vivo permeation study of Nys through porcine buccal mucosa, it could be hypothesized that no systemic effects would happen. Microbiologic studies performed revealed an enhanced antifungal effect of the Nys-loaded nanoemulsion. Also, the evaluation of the treated buccal mucosa ultrastructure by transmission electron microscopy revealed a harmless effect. Thus, it could be inferred that the developed formulation could be potentially utilized for candidosis infection under mucositis conditions.