Comparison of Characteristics of Two Topical Therapeutic Agents for Onychomycosis

Effect of Topical Antifungal Luliconazole on Hyphal Morphology of Trichophyton mentagrophytes Grown on in vitro Onychomycosis Model

Luliconazole, recently launched in Japan, is a novel topical imidazole antifungal agent for the treatment of onychomycosis. Using in vitro onychomycosis model, the effect of luliconazole on the morphology of the growing hyphae of Trichophyton mentagrophytes was investigated by scanning electron microscopy (SEM). The model was produced by placing human nail pieces on an agar medium seeded with conidia of T. mentagrophytes. After incubating the agar medium for 3 days, luliconazole was applied to the surface of the nail in which hyphal growth was recognized, then cultured for up to 24 h. The initial change after treatment with the drug was the formation of fine wrinkles on the surface of the hyphae, eventually, the hyphae were flattened, and after that, no hyphal growth was observed. On the other hand, when the nails were pretreated with luliconazole for 1 h, no hyphal growth was observed even after culturing for 24 h. This study suggests that luliconazole has a strong antifungal activity by inhibiting the ability of fungi to grow and the drug has both excellent nail permeation and retention properties.

Molecular Docking-Guided Ungual Drug-Delivery Design for Amelioration of Onychomycosis

The present work envisaged an adherent luliconazole-loaded bilayer nail lacquer (BNL) with significant transungual activity. The locally applied sustained-release BNL formulation was designed for an improved retention, payload, and final dermatokinetic disposition. A primary step in the fabrication of a BNL included overcoming of physical barriers like α-keratin (also α-keratin), a protein present in human nails, and then allowing the drug molecule to permeate at the site of action. Although luliconazole is an established antifungal agent, has limited clinical exploitation for its use in treating onychomycosis. An in silico study elucidating its interaction with lanosterol-14-α demethylase, an enzyme which is the key region of drug action mechanism, was highly supportive of its imminent clinical potential. Optimization of prepared BNL formulations via response surface modeling (Box-Behnken Design-Expert 10.0.6) logically ascertained the effect of selected independent variables and showcased its effect via dependent responses. Surface morphology of the prepared BNL films was well corroborated for the presence of two distinct polymeric layers through scanning electron microscopy imaging. Nail permeation studies revealed a cumulative drug release of 71.25 ± 0.11% through bovine hooves up to 24 h. Luliconazole while exposing antifungal activity against clinical isolates of Trichophyton rubrum in agar cup-plate method disclosed a 38 mm diameter zone of inhibition. Further, the optimized BNL exhibited a bioadhesive force of 1.9 ± 0.11 N, which assured its retention on the nail surface for prolonged duration of time. In Conclusion, it is deduced that the conventional treatment modalities for onychomycosis require circumvention of certain pharmacotechnical caveats. Therefore, in the present study, a multipronged BNL system was proposed, which negates the need of frequent drug application, improvises cosmetic appearance, yields fruitful therapeutic outcomes, and has a clinical supremacy over the available therapeutics.

In Vitro Human Onychopharmacokinetic and Pharmacodynamic Analyses of ME1111, a New Topical Agent for Onychomycosis

ME1111 is a novel antifungal agent currently under clinical development as a topical onychomycosis treatment. A major challenge in the application of topical onychomycotics is penetration and dissemination of antifungal agent into the infected nail plate and bed. In this study, pharmacokinetic/pharmacodynamic parameters of ME1111 that potentially correlate with clinical efficacy were compared with those of marketed topical onychomycosis antifungal agents: efinaconazole, tavaborole, ciclopirox, and amorolfine. An ME1111 solution and other launched topical formulations were applied to an in vitro dose model for 14 days based on their clinical dose and administration. Drug concentrations in the deep layer of the nail and within the cotton pads beneath the nails were measured using liquid chromatography-tandem mass spectrometry. Concentrations of ME1111 in the nail and cotton pads were much higher than those of efinaconazole, ciclopirox, and amorolfine. Free drug concentrations of ME1111 in deep nail layers and cotton pads were orders of magnitude higher than the MIC₉₀ value against Trichophyton rubrum (n = 30). Unlike other drugs, the in vitro antifungal activity of ME1111 was not affected by 5% human keratin and under a mild acidic condition (pH 5.0). The in vitro antidermatophytic efficacy coefficients (ratio of free drug concentration to MIC₉₀s against T. rubrum) of ME1111, as measured in deep nail layers, were significantly higher than those of efinaconazole, tavaborole, ciclopirox, and amorolfine (P < 0.05). This suggests that ME1111 has excellent permeation of human nails and, consequently, the potential to be an effective topical onychomycosis treatment.

Luliconazole, a new antifungal against Candida species isolated from different sources

OBJECTIVE

Luliconazole is an inhibitor for sterol 14-α-demethylase in fungal cells with a broad-spectrum antifungal activity against dermatophytes, Candida albicans, Malassezia species, dematiaceous and hyaline hyphomycetes. Furthermore, luliconazole has been clinically used for the treatment of pityriasis versicolor, dermatophytosis, onychomycosis, cutaneous and mucocutaneous candidiasis. In the present study, we aimed to evaluate in vitro antifungal activity of luliconazole against several strains of Candida species recovered from different clinical materials.

MATERIALS AND METHODS

In the present study, 104 strains of Candida species including, 34 isolates from vaginitis, 23 isolates from AIDS patients with vaginal candidiasis, 24 isolates from neutropenic patients and 24 isolates from tracheal tubes, were examined for susceptibility tests. A serial dilution of luliconazole (4-0.008μg/mL) was tested against different strains of Candida species recovered from different sources.

RESULTS

The minimum inhibitory concentration (MIC) range and MIC₉₀ of vaginal isolates (HIV^-) were 1-0.063 and 1μg/mL. Furthermore, the most of strains (50%) had a MIC of 0.5μg/mL. The MIC ranges were similar (2-0.016μg/mL) for both vaginal (HIV⁺) and neutropenic patients isolates, whereas, MIC₉₀ for them were 0.5 and 1μg/mL, respectively. All tracheal tubes strains were inhibited at the range of 2-0.008μg/mL with MIC₉₀=1μg/mL. Totally, the lowest MIC₅₀ (MIC=0.015μg/mL), MIC₉₀ (MIC=1μg/mL) and MIC_GM (MIC=0.05μg/mL) are correlated to C. glabrata, a non-albicans species.

CONCLUSION

It is concluded that, luliconazole could be an alternative anti-Candida agent, however, in vivo studies must be confirmed usefulness of drug for clinical usage.