Amorolfine 5% Nail Lacquer Exhibits Potent Antifungal Activity Compared to Three Acid-Based Devices Indicated for the Treatment of Onychomycosis: An In Vitro Nail Penetration Assay

Ex vivo potential of a quinoline-derivative nail lacquer as a new alternative for dermatophytic onychomycosis treatment

Introduction. Onychomycosis infections currently show a significant increase, affecting about 10 % of the world population. Trichophyton rubrum is the main agent responsible for about 80 % of the reported infections. The clinical cure for onychomycosis is extremely difficult and effective new antifungal therapy is needed.Hypothesis/Gap Statement. Ex vivo onychomycosis models using porcine hooves can be an excellent alternative for evaluating the efficacy of new anti-dermatophytic agents in a nail lacquer.Aim. Evaluation of the effectiveness of a nail lacquer containing a quinoline derivative on an ex vivo onychomycosis model using porcine hooves, as well as the proposal of a plausible antifungal mechanism of this derivative against dermatophytic strains.Methodology. The action mechanism of a quinoline derivative was evaluated through the sorbitol protection assay, exogenous ergosterol binding, and the determination of the dose-response curves by time-kill assay. Scanning electron microscopy evaluated the effect of the derivative in the fungal cells. The efficacy of a quinoline-derivative nail lacquer on an ex vivo onychomycosis model using porcine hooves was evaluated as well.Results. The quinoline derivative showed a time-dependent fungicidal effect, demonstrating reduction and damage in the morphology of dermatophytic hyphae. In addition, the ex vivo onychomycosis model was effective in the establishment of infection by T. rubrum.Conclusion. Treatment with the quinoline-derivative lacquer showed a significant inhibitory effect on T. rubrum strain in this infection model. Finally, the compound presents high potential for application in a formulation such as nail lacquer as a possible treatment for dermatophytic onychomycosis.

A pilot, layerwise, ex vivo evaluation of the antifungal efficacy of amorolfine 5% nail lacquer vs other topical antifungal nail formulations in healthy toenails

BACKGROUND

Studies investigating the penetration of amorolfine through the nail have shown the highest concentration in the uppermost layer and measurable antifungal activity even in the lower layers of the nail.

OBJECTIVES

This pilot, ex vivo study compared the penetration of antifungal concentrations of amorolfine 5% nail lacquer in different layers of healthy, human cadaver toenails with that of terbinafine 10% nail solution, ciclopirox 8% nail lacquer and naftifine 1% nail solution. Moreover, the effect of nail filing prior to application on the penetration of amorolfine 5% was assessed.

METHODS

Unfiled (n = 3) and filed (n = 3) nails were used for each antimycotic agent and amorolfine 5% nail lacquer, respectively. Twenty-four hours after topical application, the nails were sliced (10 μm), solubilised and added to agar plates seeded with Trichophyton rubrum. Zones of growth inhibition were measured.

RESULTS

Only amorolfine penetrated the nails at sufficient concentrations to inhibit growth of T rubrum at different nail depths. In contrast, the comparators did not show antifungal efficacy. Nail filing resulted in larger zones of inhibition for amorolfine compared with those of intact nails.

CONCLUSIONS

Unlike its comparators, a single application of amorolfine 5% nail lacquer resulted in antifungal efficacy within the nail plate. Nail filing increased the antifungal efficacy of amorolfine 5% nail lacquer.

COMBINATION ANTIFUNGAL THERAPY FOR ONYCHOMYCOSIS

Onychomycosis is a fungal infection of the nail unit including the nail matrix, the nail bed and the nail plate by both dermatophyte and non-dermatophyte agents. It is disturbs not only cosmetic disfigurement, but also it may have an impact on patients’ emotional, social and occupational functioning, finally affecting the overall quality of life. The incidence rate tends to increase, management of onychomycosis is still challenging. Important problems regarding antifungal monotherapy have experienced many failures and recurrences. In general, pharmacological approaches for onychomycosis can be topical or oral antifungal. Antifungal monotherapies often lead to failure treatment, also high incidence of recurrence. One strategy for this problem is a combination antifungal therapy. In vitro studies show the synergistic effect of using combination two antifungals (both oral antifungal or combination topical and oral antifungal), hence it is mycologically or clinically expected to increase the success rate of onychomycosis therapy. This review tries to evaluate the previous study exploring the effectiveness of antifungal combination therapies on onychomycosis. Two oral antifungals usually used are terbinafine as fungicidal agent and itraconazole as fungistatic agent. There is combination between topical and oral antifungal such as itraconazole or terbinafine with amorolfine or ciclopirox, also other combination like griseofulvin and amorolfone or tioconazole. All the combination therapies show better result than monotherapy alone, but it is still difficult to conclude whether antifungal combinations in onychomycosis will increase effectiveness due to variations in therapeutic duration, result definition, and statistical evaluation on existing studies. Further research is required with longer duration of observation, uniform patient criteria and definition of success, random control and blinding to minimize bias.

Efficacy and tolerability of amorolfine 5% nail lacquer in combination with systemic antifungal agents for onychomycosis: A meta-analysis and systematic review

The efficacy and safety of amorolfine 5% nail lacquer in combination with systemic antifungal agents in the treatment of the onychomycosis were evaluated. According to our meta-analysis, combination treatment of amorolfine 5% nail lacquer and systemic antifungals can result in higher percentage of complete clearance of onychomycosis. It showed that the experimental combination group was more effective than monotherapy of the systemic antifungals [OR (odds ratio) = 1.97, 95%CI (95% confidence interval) = 1.44-2.69], and no more adverse events happened with the addition of amorolfine 5% nail lacquer (OR = .96, 95%CI = .56-1.63, p = .95). This effect strengthens the fact that amorolfine 5% nail lacquer in combination with systemic antifungal agents was better than the monotherapy of systemic antifungals like itraconazole and terbinafine.