Recent advances in therapies for onychomycosis and its management

Synergistic activity between conventional antifungals and chalcone-derived compound against dermatophyte fungi and Candida spp

The scarce antifungal arsenal, changes in the susceptibility profile of fungal agents, and lack of adherence to treatment have contributed to the increase of cases of dermatomycoses. In this context, new antimicrobial substances have gained importance. Chalcones are precursors of the flavonoid family that have multiple biological activities, have high tolerability by humans, and easy synthesis. In this study, we evaluated the in vitro antifungal activity, alone and in combination with conventional antifungal drugs, of the VS02-4'ethyl chalcone-derived compound against dermatophytes and Candida spp. Susceptibility testing was carried out by broth microdilution. Experiments for determination of the target of the compound on the fungal cell, time-kill kinetics, and toxicity tests in Galleria mellonella model were also performed. Combinatory effects were evaluated by the checkerboard method. Results showed high activity of the compound VS02-4'ethyl against dermatophytes (MIC of 7.81-31.25 μg/ml). The compound targeted the cell membrane, and the time-kill test showed the compound continues to exert gradual activity after 5 days on dermatophytes, but no significant activity on Candida. Low toxicity was observed at 250 mg/kg. Excellent results were observed in the combinatory test, where VS02-4'ethyl showed synergistic interactions with itraconazole, fluconazole, terbinafine, and griseofulvin, against all isolates tested. Although further investigation is needed, these results revealed the great potential of chalcone-derived compounds against fungal infections for which treatments are long and laborious.

Exploration of synergistically engineered invasomes of fluconazole incorporated with safranal against onychomycosis for enhanced transungual delivery

OBJECTIVE

The preparation of safranal-containing invasomes for fluconazole (FLU-IN) is investigated in the current research work to augment FLU permeation, bioavailability, and solubility via nail for transungual delivery.

METHODS

FLU-IN was prepared utilizing the 'thin-film hydration process', and for optimization, 'Box-Behnken design (BBD)' was employed. Entrapment efficiency (EE), Poly-dispersity index (PDI), in vitro FLU release, vesicle size and zeta potential were used to characterize FLU-INopt. Confocal microscopy (CLSM), nail permeation investigation, and Transmission electron microscopy (TEM) were also carried out for further examination.

RESULTS

The FLU-INopt demonstrated tiny, spherical, sealed-shape vesicles with a vesicle size of 140.3 nm, PDI of 0.1604, in vitro release of 84.32%, and entrapment efficiency of 74.65%. According to the CLSM investigation, the prepared formulation exhibits better FLU penetration over the nail than FLU suspension gel. Compared to the standard fluconazole marketed gel, the anti-fungal investigation showed that the FLU-IN gel has good anti-fungal potential against Trichophyton rubrum, Nakaseomyces glabrata and Candida albicans. Additional research on Wistar albino rats' skin irritancy supports the new FLU-IN formulation's safety for topical treatment.

CONCLUSION

The present study supported the claim that the developed invasomal formulation is a desirable vesicular carrier for FLU transungual delivery for the management of onychomycosis.

Efficacy of Fractional Versus Fully Ablative CO2 Laser for Distolateral Onychomycosis: Experience With 20 Patients

INTRODUCTION

Oral antifungals are the treatment choice for onychomycosis, and topical therapies are favored in cases of limited nail involvement. Recently, carbon dioxide (CO2) laser treatment has emerged as an option to enhance the effectiveness of topical therapies.

OBJECTIVES

Our objective was to compare the efficacy of fractional ablative and fully ablative CO2 laser treatments for distolateral subungual onychomycosis affecting a single toenail and caused by dermatophytes.

METHODS

The records of 10 patients treated with a single fully ablative CO2 session were matched with those of 10 patients who underwent a single CO2 fractional treatment. All had previously failed topical antifungal lacquers and were discharged with the prescription of topical ciclopirox nail lacquer (8%) for 3 months.

RESULTS

The clinical response rates were 80% for the fully ablative group and 60% for the fractional group. Additionally, the mean reduction in Onychomycosis Severity Index from baseline to 8.6±1.6 weeks after treatment completion was 6.9±5.4 in the fully ablative group and 3.6±6.6 in the fractional group. The relapse rate among responders was 12.5% in the fully ablative and 33.3% in the fractional group after a mean follow-up time of 29.4±2.3 weeks.

CONCLUSIONS

Fractional and fully ablative CO2 laser in combination with ciclopirox lacquer could increase the response rate in onychomycosis resistant to topical antifungals when systemic therapy is contraindicated or not yet pursued. Fully ablative mode therapy is significantly more effective than fractional (P < 0.05). Further studies are needed to identify prognostic response factors and assess the long-term effectiveness of CO2 laser treatment.

Severe drug eruption from oral terbinafine for mild onychomycosis-A case report from family practice and literature review: "Just an innocent little pill?"

Onychomycosis is the most prevalent nail disease and is frequently encountered in clinical practice. Despite having multiple therapeutic options, of which systemic antifungals are the most effective, treatment is not always mandatory in all patients. Especially when considering systemic treatment, the risk of adverse reactions may outweigh the potential benefits of treatment. In this case report, we present a clinical case of a 49-year-old male patient with a blank past medical history who experienced a severe drug eruption from terbinafine prescribed for mild onychomycosis that required discontinuation of terbinafine, additional evaluation, and treatment of this adverse reaction.

Efficacy of topical trichloroacetic acid 100% either alone or combined with topical tioconazole 28% versus systemic itraconazole in the treatment of onychomycosis

BACKGROUND

Treatment of onychomycosis is still challenging and warrants the development of new treatment strategies. Different trials were conducted to increase the penetration and efficacy of topical antifungals aiming at finding an alternative treatment especially when systemic antifungals are contraindicated.

OBJECTIVES

To evaluate the efficacy of trichloroacetic acid (TCA) 100% either alone or combined with topical tioconazole 28% versus itraconazole pulse therapy in the treatment of onychomycosis.

PATIENTS/METHODS

Forty-five patients with onychomycosis were divided into three groups: group (A) treated by topical TCA 100% for 12 sessions, group (B) treated by TCA 100% for 12 sessions combined with topical tioconazole 28% for 18 weeks and group (C) treated by itraconazole (400 mg/day for 1 week/month for 4 months).

RESULTS

TCA 100% combined with topical tioconazole 28% showed the highest therapeutic response; however, the difference between the groups was statistically insignificant. Mycological cure (negative culture) was reported in 66.7% of group B versus 60% of group A and 40% of group C at the 20 week.

CONCLUSIONS

TCA 100% is an effective and safe treatment option for onychomycosis especially when combined with antifungals. This modality is promising in the treatment of onychomycosis especially with the increased resistance to different antifungals.

Utility of devices for onychomycosis: a review

Onychomycosis is difficult to treat due to long treatment durations, poor efficacy rates of treatments, high relapse rates, and safety issues when using systemic antifungal agents. Device-based treatments are targeted to specific regions of the nail, have favorable safely profiles, and do not interfere with systemic agents. They may be an effective alternative therapy for onychomycosis especially with increasing reports of squalene epoxidase gene mutations and potential resistance to terbinafine therapy. In this review, we discuss four devices used as antifungal treatments and three devices used as penetration enhancers for topical agents. Lasers, photodynamic therapy, microwaves, and non-thermal plasma have the capacity to inactivate fungal pathogens demonstrated through in vivo studies. Efficacy rates for these devices, however, remain relatively low pointing toward the need to further optimize device or usage parameters. Ultrasound, nail drilling, and iontophoresis aid in improving the permeability of topical agents through the nail and have been investigated as adjunctive therapies. Due to the paucity in clinical data, their efficacy in treating onychomycosis has not yet been established. While the results of clinical studies point toward the potential utility of devices for onychomycosis, further large-scale randomized clinical trials following regulatory guidelines are required to confirm current results.

On the Basis of Sex: Impact and Treatment of Toenail Onychomycosis in Female Patients

Onychomycosis is a fungal infection of the nail unit affecting approximately five percent of the global population and representing 50 percent of all nail dystrophies seen in clinical practice. Patients with onychomycosis can suffer significant pain in addition to physical and psychological distress, which may seriously impair their quality of life (QoL). It is well established that onychomycosis prevalence is impacted by patient characteristics, including age and systemic comorbidities. However, the impact of patient sex on onychomycosis occurrence and treatment is not well characterized. This narrative review of the literature was conducted to address a dearth of published information on epidemiology, QoL, clinical trial participation, and treatment success specifically in female patients with onychomycosis. Additionally, an analysis of real-world treatment of onychomycosis in female patients is reported, including prescription patterns and the impact of toenail polish on topical treatments for onychomycosis. Understanding sex as a clinically relevant variable may inform onychomycosis treatment strategies and improve treatment outcomes.

Linalool-Incorporated Synergistically Engineered Modified Liposomal Nanocarriers for Enhanced Transungual Delivery of Terbinafine against Onychomycosis

This work investigates the synthesis of linalool-containing invasomes for terbinafine (TBF-IN) in order to increase the solubility, bioavailability, and nail permeability of terbinafine (TBF) for transungual administration. TBF-IN was created utilising the thin-film hydration technique, and with the Box-Behnken design (BBD), optimisation was carried out. TBF-INopt were investigated for vesicle size, zeta potential, PDI (Polydispersity index), entrapment efficiency (EE) and in vitro TBF release. In addition, nail permeation analysis, TEM (transmission electron microscopy), and CLSM (confocal scanning laser microscopy) were performed for further evaluation. The TBF-INopt exhibited spherical as well as sealed vesicles with a considerably small size of 146.3 nm, an EE of 74.23 per cent, a PDI of 0.1612, and an in vitro release of 85.32 per cent. The CLSM investigation revealed that the new formulation had better TBF nail penetration than the TBF suspension gel. The antifungal investigation demonstrated that the TBF-IN gel has superior antifungal activity against Trichophyton rubrum and Candida albicans compared to the commercially available terbinafine gel. In addition, an investigation of skin irritation using Wistar albino rats indicates that the TBF-IN formulation is safe for topical treatment. This study confirmed that the invasomal vesicle formulation is an effective vehicle for the transungual delivery of TBF for the treatment of onychomycosis.

Membranolytic Activity Profile of Nonyl 3,4-Dihydroxybenzoate: A New Anti-Biofilm Compound for the Treatment of Dermatophytosis

The ability of dermatophytes to live in communities and resist antifungal drugs may explain treatment recurrence, especially in onychomycosis. Therefore, new molecules with reduced toxicity that target dermatophyte biofilms should be investigated. This study evaluated nonyl 3,4-dihydroxybenzoate (nonyl) susceptibility and mechanism of action on planktonic cells and biofilms of T. rubrum and T. mentagrophytes. Metabolic activities, ergosterol, and reactive oxygen species (ROS) were quantified, and the expression of genes encoding ergosterol was determined by real-time PCR. The effects on the biofilm structure were visualized using confocal electron microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). T. rubrum and T. mentagrophytes biofilms were susceptible to nonyl and resistant to fluconazole, griseofulvin (all strains), and terbinafine (two strains). The SEM results revealed that nonyl groups seriously damaged the biofilms, whereas synthetic drugs caused little or no damage and, in some cases, stimulated the development of resistance structures. Confocal microscopy showed a drastic reduction in biofilm thickness, and transmission electron microscopy results indicated that the compound promoted the derangement and formation of pores in the plasma membrane. Biochemical and molecular assays indicated that fungal membrane ergosterol is a nonyl target. These findings show that nonyl 3,4-dihydroxybenzoate is a promising antifungal compound.

Strategies for the enhancement of nail plate permeation of drugs to treat onychomycosis

Onychomycosis is caused by dermatophytes, non-dermatophytes and yeasts. It has a global prevalence of 5.5%, requires long treatment periods, and has high relapse rates following therapy. Oral antifungals are generally the most common treatment. While effective, they have limitations such as drug-drug interactions, hepatotoxicity and adverse side effects; thus, they cannot be used in several populations. Topical antifungals do not have the safety limitations but are typically not as effective. The primary challenge of topical treatment is the permeation of drug molecules across the nail plate barrier, which is a highly cross-linked keratin network. The use of drugs and formulations with favourable characteristics such as small size, absence of lipophilicity, hydrophilic nature, hydrating properties and appropriate pH can greatly improve permeation. Here, we review physical, nanoparticle-based, formulation-based, mechanical and chemical drug delivery strategies to improve the permeation of drugs across the nail plate.

Review of the literature on the efficacy and safety of a new cosmetic topical treatment containing Pistacia lentiscus and hyaluronic acid for the treatment of nail plate damages

OBJECTIVES

The objective of our study is the review of the literature on the efficacy and safety of a novel water-soluble nail strengthened (WSNS) containing hyaluronic acid and Pistacia lentiscus used for the improvement of nail plate diseases.

MATERIALS AND METHODS

We conducted literature research on PubMed/MEDLINE to identify all the studies reporting the use of hyaluronic acid and P. lentiscus in the improvements of nail alterations.

RESULTS

We found two reports and two posters published in the literature, accounting for 96 patients treated with WSNS containing P. lentiscus and hyaluronic acid. The 83 patients were affected by brittle nails and 13 patients by onychomycosis.

CONCLUSIONS

This review demonstrates that the daily application of this new product containing P. lentiscus and hyaluronic acid can be used as a cosmetic adjuvant for improving common nail diseases such as nail fragility and onychomycosis, with significant results on nail quality and appearance. Patients did not report any adverse events and its ease of application and cosmetic qualities contribute to the great compliance to treatment.

Investigation on Utility of Some Novel Terpenes on Transungual Delivery of Terbinafine for the Management of Onychomycosis

INTRODUCTION

Onychomycosis is a fungal disorder of the nail which afflicts 5% of the population worldwide. The disease is strenuous to cure as it is chronic, hard to eliminate and tends to recur. Topical therapy is at the forefront for the treatment of many disorders of nail. However, the success rate of topical therapy has been halted owing to the poor permeation of topical therapeutics across densely keratinized nail barrier. Therefore, ungual drug permeation must be improved for an effective topical therapy. An approach to achieve this goal would be the use of terpenes from natural sources as potential penetration enhancers.

OBJECTIVE

This study is aimed to explore the effectiveness of some novel terpenes as potential penetration enhancers on transungual delivery of terbinafine.

METHODS

Ex-vivo permeation studies were performed by sopping the nail clippings of healthy human volunteers in control and working solutions containing terbinafine (5mg/ml) per se and terbinafine (5mg/ml) with 6% of each terpenes including lavandulol, safranal, rose oxide, limonene, 3-methyl-2-butene-1-ol, and linalool respectively for 48 hours. The terbinafine concentration in nail samples was determined using a HPLC (High Performance Liquid Chromatography method.

RESULTS

Statistical analysis showed that studied terpenes increase transungual penetration of terbinafine in the following order: linalool > rose oxide > 3-methyl-2-butene-1-ol > safranal > limonene > lavandulol acetate. Accordingly, linalool was found to be the most effective penetration enhancer for the transungual delivery of terbinafine.

CONCLUSIONS

It is concluded that linalool can be used as safe and potential penetration enhancer for enhancing the transungual delivery of terbinafine for onychomycosis.

Fractional CO2 laser ablation leads to enhanced permeation of a fluorescent dye in healthy and mycotic nails-An imaging investigation of laser-tissue effects and their impact on ungual drug delivery

Purpose

Conventional oral antifungal therapies for onychomycosis (OM) often do not achieve complete cure and may be associated with adverse effects, medical interactions, and compliance issues restricting their use in a large group of patients. Topical treatment can bypass the systemic side effects but is limited by the physical barrier of the nail plate. Ablative fractional laser (AFL) treatment can be used to improve the penetration of topical drugs into the nail. This study visualized the effects of laser ablation of nail tissue and assessed their impact on the biodistribution of a fluorescent dye in healthy and fungal nail tissue.

Methods

For the qualitative assessment of CO₂ AFL effects on healthy nail tissue, scanning electron microscopy (SEM), coherent anti‐Stokes Raman scattering microscopy (CARS‐M), and widefield fluorescence microscopy (WFM) were used. To quantitate the effect of laser‐pretreatment on the delivery of a fluorescent dye, ATTO‐647N, into healthy and fungal nail tissue, ablation depth, nail plate thickness, and ATTO‐647N fluorescence intensity in three nail plate layers were measured using WFM. A total of 30 nail clippings (healthy n = 18, fungal n = 12) were collected. An aqueous ATTO‐647N solution was directly applied to the dorsal surface of 24 nail samples (healthy n = 12, fungal n = 12) and incubated for 4 hours, of which half (healthy n = 6, fungal n = 6) had been pretreated with AFL (30 mJ/mb, 15% density, 300 Hz, pulse duration <1 ms).

Results

Imaging revealed a three‐layered nail structure, an AFL‐induced porous ablation crater, and changes in autofluorescence. While intact fungal samples showed a 106% higher ATTO‐647N signal intensity than healthy controls, microporation led to a significantly increased fluorophore permeation in all samples (p < 0.0001). AFL processing of nail tissue enhanced topical delivery of ATTO‐647N in all layers, (average increase: healthy +108%, fungal +33%), most pronounced in the top nail layer (healthy +122%, fungal +68%). While proportionally deeper ablation craters correlated moderately with higher fluorescence intensities in healthy nail tissue, fungal samples showed no significant relationship.

Conclusion

Fractional CO₂ laser microporation is a simple way of enhancing the passive delivery of topically applied ATTO‐647N. Although the impaired nail plate barrier in OM leads to greater diffusion of the aqueous solution, AFL can increase the permeability of both structurally deficient and intact nails.

Investigation on utility of some novel terpenes on transungual delivery of fluconazole for the management of onychomycosis

BACKGROUND

Onychomycosis, the most prevailing affliction of the nail, accounts for approximately 90% of the toenail infection worldwide. Owing to this infection, the affected patients experience reduced quality of their life as its awful appearance undermines their daily activities and social interactions. Onychomycosis is notoriously strenuous to cure. Systemic therapy, though effective, possess severe complication of toxicities, contra-indication, and drug-drug interaction. Albeit topical therapy is favorable to its localized effect, its potency relates to the effective concentration of the antifungal drugs achieved at the infection site. An approach to accomplish this goal would be acquiring benefits from the terpenes as penetration enhancers from natural sources. This investigation aimed to study the effectiveness of six terpenes, namely safranal, lavandulol, rose oxide, 3-methyl-2-butene-1-ol, linalool, and limonene, as potential penetration enhancers for improved nail permeation of fluconazole through the human nail.

METHODS

Ex vivo permeation experiments were carried out by soaking the nail clippings of human volunteers in control and working solutions containing fluconazole (5 mg/ml) per se and fluconazole (5 mg/ml) with 6% of each terpene, including safranal, lavandulol, rose oxide, 3-methyl-2-butene-1-ol, linalool, and limonene, respectively, for 48 hours. The amount of fluconazole in nail clippings was quantified using an HPLC method.

RESULTS

Statistical analysis showed that fluconazole transungual permeation was influenced by the studied terpenes in the following order: safranal > lavandulol acetate > limonene > rose oxide (P-value > 0.05) while the other terpenes showed no significant difference with the control group and safranal represents as the most effective permeation enhancer for the transungual delivery of fluconazole.

CONCLUSION

It is concluded that the safranal can be successfully used as a safe and potential permeation enhancer to enhance the transungual delivery of fluconazole for the treatment of onychomycosis.

Non-Dermatophyte Mold Dominated Onychomycosis in Patients Attending a Rank Higher Specialized Dermatology Clinic in Addis Ababa, Ethiopia

Background

Onychomycosis is a common refractory fungal infection associated with significant morbidity. The objective of this study was to determine the prevalence of onychomycosis, and the diversity and species composition of fungal etiological agents.

Materials and Methods

A clinic-based, prospective, non-randomized cross-sectional study was carried out between October 2018 and June 2019 at Rank Higher Specialized Dermatology Clinic, Addis Ababa, Ethiopia. Nail scrapings were collected aseptically from 200 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.

Results

Among 200 nail scrapings, 161 (80.5%) samples were found out to be culture positive. Of these, 135 (83.9%) samples yielded single colonies while 26 (16.1%) mixed colonies gave a total of 190 isolates. Among the isolates, 25.8% were dermatophytes while 61.1% were non- dermatophytes molds, and 13.1% were yeasts. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant species.

Conclusion

The prevalence rate of onychomycosis in the present study was high. The isolation rate of non-dermatophyte molds was higher than dermatophytes and yeasts. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant etiological agents. Females and patients in the middle age group were more affected. An increase in the prevalence of non-dermatophyte molds in nail infections dictates further investigation demonstrating how this group of fungi causes onychomycosis.

Synthesis and Evaluation of the Antifungal and Toxicological Activity of Nitrofuran Derivatives

Fungal diseases affect more than 1 billion people worldwide. The constant global changes, the advent of new pandemics, and chronic diseases favor the diffusion of fungal pathogens such as Candida, Cryptococcus, Aspergillus, Trichophyton, Histoplasma capsulatum, and Paracoccidioides brasiliensis. In this work, a series of nitrofuran derivatives were synthesized and tested against different fungal species; most of them showed inhibitory activity, fungicide, and fungistatic profile. The minimal inhibitory concentration (MIC90) values for the most potent compounds range from 0.48 µg/mL against H. capsulatum (compound 11) and P. brasiliensis (compounds 3 and 9) to 0.98 µg/mL against Trichophyton rubrum and T. mentagrophytes (compounds 8, 9, 12, 13 and 8, 12, 13, respectively), and 3.9 µg/mL against Candida and Cryptococcus neoformans strains (compounds 1 and 5, respectively). In addition, all compounds showed low toxicity when tested in vitro on lung cell lines (A549 and MRC-5) and in vivo in Caenorhabditis elegans larvae. Many of them showed high selectivity index values. Thus, these studied nitrofuran derivatives proved to be potent against different fungal species, characterized by low toxicity and high selectivity; for these reasons, they may become promising compounds for the treatment of mycoses.

Acitretin: Could it be a new therapeutic player in the field of onychomycosis?

BACKGROUND

Onychomycosis represents a therapeutic challenge. The complete cure rate with itraconazole pulse therapy remains unsatisfactory implying the need for an effective therapeutic regimen. Given the successful treatment of recurrent dermatophytosis with isotretinoin and itraconazole, we investigated the therapeutic use of acitretin in onychomycosis.

AIM

To evaluate and compare the efficacy of combined itraconazole and acitretin versus monotherapy with each in onychomycosis.

PATIENTS AND METHODS

The study included 135 adult patients with finger- and/or toe-nail onychomycosis. They were equally subdivided into 3 groups: Itraconazole pulse therapy, acitretin, and combined itraconazole/acitretin therapy. The drugs were administered for 3 months. Evaluation of severity was done by onychomycosis severity index score. Potassium hydroxide microscopy and culture were performed at baseline and at the end of the study.

RESULTS

Mycological and complete cure of onychomycosis was observed in 51.1% and 20% of the itraconazole group, 28.9% and 28.9% of the acitretin group, and 80% and 53.3% of the combined group. There was a statistically-significant difference between groups in favor of the combined itraconazole/acitretin therapy (P ≤ 0.05).

LIMITATIONS

Small sample and short therapy duration.

CONCLUSIONS

Acitretin could be a powerful therapeutic player in the field of onychomycosis, with greater efficacy when combined with itraconazole.

In Silico Drug Screening Based Development of Novel Formulations for Onychomycosis Management

Onychomycosis is a prominent fungal infection that causes discoloration, thickening, and mutilation leading to the separation of the nail from the nail bed. Treatment modalities for onychomycosis may include oral, topical, or combination therapy with antifungals and at times may require chemical or surgical intervention. The burden of side effects of antifungals is enormous, and therefore using molecular docking-based drug selection in context with the target keratin protein would ensure better disease management. Ciclopirox, Amorolfine HCl, Efinaconazole, Tioconazole, and Tavaborole were submitted for assessment, revealing that Amorolfine HCl is the best fit. Consequently, two formulations (Nail lacquer and nanoemulgel) were developed from Amorolfine HCl to validate the in silico screening outcomes. The formulations were further fortified with over-the-counter ingredients vis-a-vis with vitamin E in nail lacquer and undecylenic acid in nanoemulgel for their prominent roles in improving nail health. Both the formulations were systematically designed, optimized, and characterized. Amorolfine HCl containing nanoemulgel (NEG) was developed using undecylenic acid as an oil phase and thioglycolic acid as a penetration enhancer. The quality parameters evaluated were particle size, the zeta potential for nanoemulsion (NE) (78.04 ± 4.724 nm and −0.7mV, respectively), in vitro cumulative drug release (96.74% for NE and 88.54% for NEG), and transungual permeation (about 73.49% for NEG and 54.81% for NE). Nail lacquer was evaluated for the drying time, non-volatile content, and blush test. In vitro cumulative drug release of the developed nail lacquer and comparator marketed formulations were around 81.5% and 75%, respectively. Similarly, the transungual drug permeation was 6.32 μg/cm² and 5.89 μg/cm², respectively, in 24 h. The in silico guided preparation of both formulations containing Amorolfine HCl and over the counter ingredients is amenable for therapeutic use against onychomycosis and will be evaluated in the in vivo model.

Constant Voltage Iontophoresis Technique to Deliver Terbinafine via Transungual Delivery System: Formulation Optimization Using Box-Behnken Design and In Vitro Evaluation

Topical therapy of antifungals is primarily restricted due to the low innate transport of drugs through the thick multi-layered keratinized nail plate. The objective of this investigation was to develop a gel formulation, and to optimize and evaluate the transungual delivery of terbinafine using the constant voltage iontophoresis technique. Statistical analysis was performed using Box–Behnken design to optimize the transungual delivery of terbinafine by examining crucial variables namely concentration of polyethylene glycol, voltage, and duration of application (2–6 h). Optimization data in batches (F1–F17) demonstrated that chemical enhancer, applied voltage, and application time have influenced terbinafine nail delivery. Higher ex vivo permeation and drug accumulation into the nail tissue were noticed in the optimized batch (F8) when compared with other batches (F1–F17). A greater amount of terbinafine was released across the nails when the drug was accumulated by iontophoresis than the passive counterpart. A remarkably higher zone of inhibition was observed in nails with greater drug accumulation due to iontophoresis, as compared to the passive process. The results here demonstrate that the optimized formulation with low voltage iontophoresis could be a viable and alternative tool in the transungual delivery of terbinafine, which in turn could improve the success rate of topical nail therapy in onychomycosis.

The effects of CO2 laser and topical agent combination therapy for onychomycosis: A meta-analysis

The routine options for onychomycosis are oral, topical, and device-based therapies which are often limited in terms of efficacy and unsatisfactory side effects. Topical agents such as luliconazole, tioconazole, terbinafine, and tazarotene can be more effective when combined with laser therapies. Our aim was to compare the efficacy and satisfaction rates of CO₂ laser therapy with topical agents in patients with onychomycosis. PubMed, the Cochrane Library, Embase, and Ovid databases were searched to identify randomized controlled trials (RCTs) evaluating the effects of combined therapies. Selected study data were analyzed for differences expressed as odds ratio (OR) and relative ratio (RR) with 95% confidence intervals (CI) for dichotomous outcomes. Efficacy and satisfaction outcomes were assessed using quantitative methods. Our investigations showed that combined CO₂ laser and topical treatments significantly increased efficacy 5.38-fold when compared with topical agents alone (OR 5.38; 95% CI; 3.20-9.04; p < 0.00001), with low heterogeneity observed among studies (I²  = 38%). Mycological clearance comparison rates were also improved by combined treatments. The higher satisfaction of the combined group was assessed by pooled effect (OR 4.56; 95% CI; 2.78-7.49; p < 0.00001). Our evidence suggests combined therapy may exert positive effects and satisfactory safety for patients with moderate to severe onychomycosis, however, optimal combination options and appropriate dosages require more comprehensive RCTs.

Application of central composite design for the optimization of itraconazole loaded nail lacquer formulation

Onychomycosis is a common fungal infection of the nails that mostly affects the elderly and athletes. Antifungal drug-like itraconazole is one of the therapeutic agents of choice for the topical treatment of onychomycosis. The current work aimed for the preparation and optimization of itraconazole-loaded nail lacquer formulation. Central composite design was employed; independent variables were polymer concentration (X₁) and thioglycolic acid (TGA) concentration (X₂). While the dependent variables were cumulative amount of drug permeated per unit area (CADP/A, Y₁), drying time (Y₂) and nonvolatile content (Y₃). The optimized formulation was characterized for various parameters including ex-vivo permeation study, confocal laser scanning microscopy (CLSM) and antifungal study. The optimized nail lacquer formulation (F7) exhibited CADP/A of 198.23 µg/cm², drying time of 185 s and nonvolatile content of 97.23%. The scanning electron microscopy of goat hoof treated with optimized nail lacquer formulation demonstrated loosening of the structure and marked increase in surface roughness. The CLSM micrograph of goat hoof treated with optimized nail lacquer formulation demonstrated that the probe dye was eventually distributed and penetrated through the hoof. Bio-adhesiveness analysis showed that the prepared nail lacquer film has ample adhesiveness to be maintained on the nail plate surface for a sufficient time. In antifungal study, the optimized nail lacquer, and marketed gel exhibited a zone inhibition of 21 mm, and 10 mm against Candida albicans, respectively. The stability study showed that the optimized nail lacquer is stable at storage condition. The prepared nail lacquers have been shown to serve as a useful dosage form for the delivery of itraconazole across nail plate for controlling the problems associated with onychomycosis.

Efinaconazole topical solution (10%) for the treatment of onychomycosis in adult and pediatric patients

Introduction: Onychomycosis, a common nail disorder caused by fungal infection, can be managed pharmaceutically with oral or topical treatments. While oral treatments are often used first-line to treat nail infections, these systemic antifungals are not appropriate for all patients, and no oral treatments are approved for use in children in the USA. Given this need, topical antifungals were developed, which can be used as monotherapy or in combination with oral drugs.Areas Covered: Efinaconazole 10% solution is an azole antifungal indicated for topical treatment of toenail onychomycosis in pediatric and adult patients. This qualitative literature review summarizes available chemical, pharmacological, efficacy, safety, and post-marketing surveillance data of efinaconazole 10% topical solution. Efinaconazole 10% has been shown to be safe and efficacious regardless of disease severity/duration at baseline; patient gender, ethnicity, or age (including pediatrics); or comorbidities such as diabetes or tinea pedis. Overall, efinaconazole is a safe and effective clinical option for the treatment and management of onychomycosis.Expert Opinion: Efinaconazole is the first new antifungal approved for onychomycosis in 10 years in the USA. It has comparable efficacy to systemic antifungal agents such as itraconazole, and a favorable adverse events profile with minimal systemic exposure and no drug-drug interactions.

Cure Rates of Control Interventions in Randomized Trials for Onychomycosis Treatments: A Systematic Review and Meta-Analysis

Background: The efficacy of antifungals for onychomycosis has been determined in randomized controlled trials (RCTs); interestingly their control arms have demonstrated some therapeutic effects. These controls constitute either placebos (inert pills) or vehicles (all but the antifungal component of the creams). The objective of this research was to determine (i) whether RCT controls exhibited statistically-relevant efficacy rates (i.e. beyond the "placebo effect"), (ii) whether oral and topical controls differed in their efficacies, and (iii) if the efficacy rates of the controls correlated with those of the active comparator associated with that control.

Methods: RCTs of oral and topical monotherapies for dermatophyte toenail onychomycosis were identified through a systematic literature search. For our meta-analyses of cure rates the double arcsine transformation was used. The N-1 chi squared test was used to determine whether the cure rates significantly differed between topical and oral controls. Correlation was investigated using Kendall rank correlation tests.

Results: The pooled mycological, complete, and clinical cure rates of all control interventions (n = 19 trials) were 9%, 1%, and 6%, respectively. The pooled efficacy rates for oral and topical controls were: mycological cure rate, 7% and 12% (p=0.0016); complete cure rate, 1% for both; and clinical cure rate, 4% and 8%, respectively (p=0.0033). For oral RCTs, the respective cure rates of the active therapies were not correlated with controls. However, for topical RCTs, as the mycological and clinical cure rates of the active therapy increased, so did those of the topical vehicle associated with the active therapy in question, and vice versa.

Conclusions: The topical vehicle cure rates were often higher than the oral placebo cure rates, likely due to the presence of non-antifungal chemicals (e.g. moisturizers, urea) with antifungal and debriding properties, which are not present in oral controls.

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The Growing Problem of Antifungal Resistance in Onychomycosis and Other Superficial Mycoses

Superficial mycoses are becoming increasingly resistant to current antifungal medications. As alternative therapeutic options are limited, the increasing frequency of reports of antifungal resistance is alarming. This epidemic parallels the rise of antibiotic resistance; however, the significance of this problem has yet to gain global attention. Here, we discuss the reports of antifungal resistance from around the world, present our own experience with treatment-resistant infections, and examine alternative treatment strategies. The majority of reports of recalcitrant infections indicate terbinafine resistance as the causative factor. Single-point mutations in the squalene oxidase gene is the most reported mechanism of resistance to terbinafine. Mixed infections of dermatophytes with non-dermatophyte molds and/or yeasts are becoming more prevalent and contributing to the resistant nature of these infections. The key to selecting an effective antifungal therapy for a recalcitrant infection is identification of the infectious organisms(s) and testing susceptibility of the organism(s) to antifungal drugs. Combination and sequential therapy regimens are options, but both require active monitoring for hepatic and renal function, drug interactions, and other adverse effects. Selected topical antifungals with a wide spectrum of activity may also be considerations in some clinical presentations. Innovative treatment regimens and novel therapeutics are needed to overcome the rising epidemic of antifungal resistance.

Onychomycosis: An Updated Review

Background: Onychomycosis is a common fungal infection of the nail.

Objective: The study aimed to provide an update on the evaluation, diagnosis, and treatment of onychomycosis.

Methods: A PubMed search was completed in Clinical Queries using the key term “onychomycosis”. The search was conducted in May 2019. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews published within the past 20 years. The search was restricted to English literature. Patents were searched using the key term “onychomycosis” in www.freepatentsonline.com.

Results: Onychomycosis is a fungal infection of the nail unit. Approximately 90% of toenail and 75% of fingernail onychomycosis are caused by dermatophytes, notably Trichophyton mentagrophytes and Trichophyton rubrum. Clinical manifestations include discoloration of the nail, subungual hyperkeratosis, onycholysis, and onychauxis. The diagnosis can be confirmed by direct microscopic examination with a potassium hydroxide wet-mount preparation, histopathologic examination of the trimmed affected nail plate with a periodic-acid-Schiff stain, fungal culture, or polymerase chain reaction assays. Laboratory confirmation of onychomycosis before beginning a treatment regimen should be considered. Currently, oral terbinafine is the treatment of choice, followed by oral itraconazole. In general, topical monotherapy can be considered for mild to moderate onychomycosis and is a therapeutic option when oral antifungal agents are contraindicated or cannot be tolerated. Recent patents related to the management of onychomycosis are also discussed.

Conclusion: Oral antifungal therapies are effective, but significant adverse effects limit their use.Although topical antifungal therapies have minimal adverse events, they are less effective than oral antifungal therapies, due to poor nail penetration. Therefore, there is a need for exploring more effective and/or alternative treatment modalities for the treatment of onychomycosis which are safer and more effective.

NP213 (Novexatin®): A unique therapy candidate for onychomycosis with a differentiated safety and efficacy profile

NP213 (Novexatin®) is a novel antifungal peptide specifically designed for the topical treatment of onychomycosis. NP213 was designed using host defense peptides (HDP), essential components of the innate immune response to infection, as a template. NP213 is a water-soluble cyclic fungicidal peptide that effectively penetrates human nail. NP213 demonstrated a promising preclinical and clinical safety profile, with no evidence of systemic exposure following topical application to the skin and nails. NP213 was efficacious in two phase IIa human trials with 43.3% of patients having no fungi detectable by culture of fragments from NP213-treated nails after 180 days in the first study and likewise 56.5% of patients were culture negative for dermatophytes after 360 days in the second phase IIa study. In both trials, NP213 was applied daily for only 28 days in marked contrast to other topical onychomycosis treatments that require application for up to 52 weeks. Patient reported outcomes from the phase IIa studies were positive with participants recording an improved appearance of their nails after only 14 days of application. All fungi identified in these studies were Trichophyton spp. NP213 (Novexatin®) is a promising, highly differentiated peptide-based candidate for the topical treatment of onychomycosis, addressing the infectious cause and cosmetic issues of this very common condition.

Onychomycosis in children - review on treatment and management strategies

BACKGROUND

Onychomycosis is an uncommon condition in children with increasing global prevalence. Health practitioners should confirm the diagnosis through mycology examination and examine family members of affected individuals for onychomycosis and tinea pedis.

OBJECTIVE

To comprehensively summarize the treatment and management strategies for pediatric onychomycosis.

METHODS

We performed a comprehensive literature search in the PubMed database to identify clinical studies on treatment for mycologically-confirmed dermatophyte onychomycosis in children <18 years. The exclusion criteria were combination therapy, case reports, reviews, systematic reviews and duplicate studies.

RESULTS

Per-weight dosing regimens of systemic antifungal agents such as terbinafine, itraconazole, and fluconazole are found to be safe in children and are used off-label for the treatment of pediatric onychomycosis with high efficacy. Topical antifungal agents such as ciclopirox, efinaconazole, and tavaborole have established safety and efficacy in children. Children respond better than adults to topical therapy due to their thinner, faster growing nails. There is no data on the efficacy of medical devices for onychomycosis in children.

CONCLUSION

Efinaconazole topical solution 10% and tavaborole topical solution 5% are FDA approved for the treatment of onychomycosis in children ≥6 years; ciclopirox topical solution 8% nail lacquer is approved in children ≥12 years.

An Open Study to Evaluate Effectiveness and Tolerability of a Nail Oil Composed of Vitamin E and Essential Oils in Mild to Moderate Distal Subungual Onychomycosis

BACKGROUND

Onychomycosis is the most common nail disease and can affect both fingernails and toenails. When possible, topical treatment is generally preferred both by patients and physicians because it is associated with lower risk of systemic side effects and drug interactions than oral antifungals, avoiding laboratory monitoring.

OBJECTIVE

The aim of our study was to evaluate the efficacy, tolerability, and patient's compliance of a new topical antifungal containing vitamin E and essential oils of lime, oregano, and tea tree.

PATIENTS AND METHODS

We enrolled 20 patients with mild-moderate distal subungual onychomycosis due to dermatophytes or non-dermatophyte molds. The product was applied once daily on the periungual tissues and on the nail plate for 6 months. Follow-up without therapy continued for another 6 months in order to evaluate the product's effect maintenance. Periodic evaluation of treatment efficacy was performed by standardized photography and mycological examination (KOH + culture) of the target nail at baseline (T0), after 3 months (T1) and 6 months (T2) of therapy, and after 6 months of follow-up (T3).

RESULTS

At the end of the 12-month study, the majority of patients achieved a complete cure of onychomycosis (78.5%). All patients were very satisfied by the treatment. No side effects were recorded.

CONCLUSIONS

The results of our study indicate that this new topical antifungal containing vitamin E and essential oils of lime, oregano, and tea tree is an effective and safe option for topical therapy of onychomycosis. This topical antifungal nail oil restructures the nail appearance, improving patient's adherence to therapy and reducing the risk of relapses, maintaining results over time.

A Week of Oral Terbinafine Pulse Regimen Every Three Months to Treat all Dermatophyte Onychomycosis

Terbinafine has proved to treat numerous fungal infections, including onychomycosis, successfully. Due to its liver metabolization and dependency on the cytochrome P450 enzyme complex, undesirable drug interaction are highly probable. Additionally to drug interactions, the treatment is long, rising the chances of the appearance of side effects and abandonment. Pharmacokinetic data suggest that terbinafine maintains a fungicidal effect within the nail up to 30 weeks after its last administration, which has aroused the possibility of a pulse therapy to reduce the side effects while treating onychomycosis. This study's goal was to evaluate the effectiveness of three different oral terbinafine regimens in treating onychomycosis due to dermatophytes. Sixty-three patients with onychomycosis were sorted by convenience in three different groups. Patients from group 1 received the conventional terbinafine dose (250 mg per day for 3 months). Group 2 received a monthly week-long pulse-therapy dose (500 mg per day for 7 days a month, for 4 months) and group 3 received a 500 mg/day dose for 7 days every 3 months, totaling four treatments. There were no statistical differences regarding the effectiveness or side effects between the groups. Conclusion: A quarterly terbinafine pulse regimen can be a possible alternative for treating onychomycosis caused by dermatophytes.