The use of nanotechnology significantly reduced the amount of efinaconazole needed to effectively treat nail fungus in a study that pitted nitric oxide–releasing nanoparticles combined with the antifungal against reference strains of Trichophyton rubrum.
Efinaconazole has demonstrated effectiveness as a topical treatment for T. rubrum, but treatment can be expensive, with a single 4-mL bottle costing $691 at a major chain pharmacy, wrote Caroline B. Costa-Orlandi, PhD, of Universidade Estadual Paulista, Sao Paulo, Brazil, and her colleagues.
In a study published in the Journal of Drugs in Dermatology, an international research team evaluated topical efinaconazole and topical terbinafine, each combined with previously characterized, nitric oxide–releasing nanoparticles (NO-np) in a checkerboard design, to attack two reference strains of T. rubrum, ATCC MYA-4438 and ATCC 28189. NO-np was combined with 10% efinaconazole or with terbinafine.
The combination of NO-np and efinaconazole reduced the minimum inhibitory concentration (MIC) of efinaconazole by 16 times compared with treatment alone against ATCC MYA-4438; by 4 times when combined against ATCC 28189. With NO-np plus terbinafine, MICs against ATCC 28189 and ATCC MYA-4438 were reduced by four- and twofold, respectively, when compared with terbinafine alone. These data follow recently published findings in a study cited by the authors that demonstrated that NO-np is superior to topical terbinafine 1% cream in clearing infection in a mouse model of deep dermal dermatophytosis, suggesting that the combination may be even more effective (Nanomedicine. 2017 Oct;13[7]:2267-70).
“What we found was that we could impart the same antifungal activity at the highest concentrations tested of either alone by combining them at a fraction of these concentrations,” corresponding author Adam Friedman, MD, professor of dermatology, George Washington University, Washington, said in a press release issued by the university. The impact of this combination, “which we visualized using electron microscopy as compared to either product alone, highlighted their synergistic damaging effects at concentrations that would be completely safe to human cells,” he added.
Other benefits of NO-np include low cost, safety, ease of use, reduced likelihood for the development of antimicrobial resistance, and proven efficacy against other dermatophyte infections, the researchers noted.
The findings support the potential value of further research to evaluate nanoparticles combined with topical antifungals in a clinical setting, they said.
Dr. Costa-Orlandi had no financial conflicts to disclose. Authors Adam Friedman, MD, and Joel Friedman, MD, are coinventors of the nitric oxide–releasing nanoparticles used in the study. Dr. Adam Friedman is on the advisory board of Dermatology News.
SOURCE: Costa-Orlandi C et al. J Drugs Dermatol. 2018;17(7):717-20.