Polishing the Therapy of Onychomycosis Induced by Candida spp.: Amphotericin B–Loaded Nail Lacquer

Abstract

Onychomycosis induced by <i>Candida</i> spp. has several limitations regarding its treatment. Nail lacquers display the potential to overcome these drawbacks by providing therapeutic compliance and increasing local drug bioavailability. Thus, this work aimed to produce a nail lacquer loaded with Amphotericin B (AmB) and evaluate its performance. The AmB-loaded nail lacquer was produced and preliminarily characterized. An AmB quantification method was developed. Stability, drug release, permeability and anti-<i>Candida</i> activity assays were conducted. The analytical method validation met the acceptance criteria. The drug loading efficiency was 100% (0.02 mg/g of total product), whereas the AmB stability was limited to ≅7 days (≅90% remaining). The nail lacquer displayed a drying time of 187 s, non-volatile content of around 20%<i>_w/w</i>, water-resistance of approximately 2%<i>_w/w</i> of weight loss and satisfactory in vitro adhesion. Moreover, the in vitro antifungal activity against different <i>Candida</i> spp. strains was confirmed. The AmB release and the ex vivo permeability studies revealed that AmB leaves the lacquer and permeates the nail matrix in 47.76 ± 0.07% over 24 h. In conclusion, AmB-loaded nail lacquer shows itself as a promising extemporaneous dosage form with remarkable anti-<i>Candida</i> activity related to onychomycosis.