Gel-Cream Containing Biogenic Silver Nanoparticles and Essential Oils for the Treatment of Pityriasis Versicolor: Development and Antifungal Efficacy

Pityriasis versicolor is a superficial fungal infection caused by lipophilic yeasts of the genus Malassezia spp., characterized by a skin pigmentation disorder. Topical antifungal agents are commonly used for treatment; however, conventional therapies often lead to disease recurrence. This study aimed to develop and characterize an oil-in-water moisturizing emulsion containing biogenic silver nanoparticles and essential oils from Origanum vulgare and Melaleuca alternifolia as a potential treatment for pityriasis versicolor. The antifungal activity of the active ingredients against Malassezia pachydermatis was evaluated using disk diffusion, minimum inhibitory concentration, minimum fungicidal concentration, and checkerboard assays. Eight formulations were developed: one control and seven with active compounds, either alone or in binary or ternary combinations. Pharmacotechnical characteristics were assessed through organoleptic and physicochemical tests, along with a stability study. The antifungal efficacy of the formulations was evaluated using time-kill and scanning electron microscopy assays against M. pachydermatis . The essential oils and silver nanoparticles exhibited antifungal activity. All formulations demonstrated appropriate organoleptic and physicochemical characteristics for topical use. The formulation containing 3% biogenic silver nanoparticles showed the best spreadability and acted as a fungicide against M. pachydermatis within 48 h of treatment. Scanning electron microscopy revealed deformed fungal cells with physical damage and morphological changes. The formulation containing biogenic silver nanoparticles was identified as a potential antifungal alternative for the treatment of pityriasis versicolor. This is the first time biogenic silver nanoparticles have been incorporated into a topical cream, creating a nanotechnological product for pityriasis versicolor treatment, with promising potential in the pharmaceutical field.