[Affinity of Luliconazole for Human Nail Derived Keratin]

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.

A comparative study between two antifungal agents, Luliconazole and Efinaconazole, of their preventive effects in a Trichophyton-infected guinea pig onychomycosis model

An efficacious period of two topical antifungal drugs was compared in a Trichophyton mentagrophytes-infected onychomycosis model in guinea pigs treated with antifungal drugs prior to infection. Luliconazole 5% (LLCZ) and efinaconazole 10% (EFCZ) test solutions were applied to the animals’ nails once daily for 2 weeks followed by a nontreatment period of 2, 4, and 8 weeks. After each nontreatment period, the nails were artificially infected by the fungus. Drug efficacy was quantitatively evaluated by qPCR and histopathological examination of the nails collected following a 4-week post-infection period. The fungal infection was confirmed in the untreated group. Both LLCZ and EFCZ prevented fungal infection in the treated groups with the nontreatment period of 2 weeks. After the nontreatment period of 4 weeks, no infection was observed in the LLCZ-treated group; however, infection into the nail surface and fungal invasion into the nail bed were observed in the EFCZ-treated group. After the nontreatment period of 8 weeks, fungi were found in the nail surface and nail bed in some nails treated with EFCZ; however, no infection was observed in the nail bed of the LLCZ-treated group. The results suggest that LLCZ possesses longer-lasting antifungal effect in nails of the guinea pigs than EFCZ, and that this animal model could be useful for translational research between preclinical and clinical studies to evaluate the pharmacological efficacy of antifungal drugs to treat onychomycosis. This experimentally shown longer-lasting preventive effects of LLCZ could also decrease the likelihoods of onychomycosis recurrence clinically.

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.