Clove Oil-Based Nanoemulsion Containing Amphotericin B as a Therapeutic Approach to Combat Fungal Infections.

Background/

Objectives

Candidiasis, primarily caused by Candida albicans, and sporotrichosis, mainly caused by Sporothrix schenckii, are skin fungal infections that pose serious threats to global health. The Candida auris is a great concern in immunocompromised individuals, and while Sporothrix brasiliensis cause sporotrichosis, an infection commonly found in cats, this disease can be transmitted to humans through scratches or bites. Existing treatments for these fungal infections often cause problems related to resistance and significant side effects. Consequently, development of alternative therapeutic approaches such as nanotechnology-based topical lipid-based formulations is interesting. Thus, the objectives of this study were to prepare clove oil (CO)-in-water nanoemulsions (NEs) containing amphotericin B (AmB) and characterize them with respect to stability, release profile, and in vitro cytotoxic activity against Candida and Sporothrix strains. As a future alternative for the treatment of fungal skin diseases.

Methods

Chemical analysis of clove oil was obtained by GC-MS. The NEs were produced using an ultrasound (sonicator) method with varying proportions of CO, Pluronic® F-127, and AmB. The NEs were characterized by droplet size, morphology, stability and in vitro release profile. The antifungal and cytotoxic activity against C. albicans, C. auris, S. schenckii, and S. brasiliensis were ascertained employing agar diffusion and colorimetric MTT assay methods. A checkerboard assay was carried out using clove oil and amphotericin B against C. auris.

Results

Eugenol was the major compound identified in CO at a concentration of 80.09%. AmB-loaded NEs exhibited particle sizes smaller than 50 nm and a polydispersity index below 0.25. The optimal Ne (NEMLB-05) remained stable after 150 days of storage at 4 °C. It exhibited rapid release within the first 24 h, followed by a slow and controlled release up to 96 h. NEMLB-05 more effectively inhibited C. auris compared to free AmB and also demonstrated greater activity against C. albicans, S. schenckii, and S. brasiliensis. Clove oil and amphotericin B presented synergism inhibiting the growth of C. auris.

Conclusions

The selected CO-in-water NEs containing AmB demonstrated promising potential as a topical therapeutic alternative for treating fungal infections.