Challenges and Opportunities in the Management of Onychomycosis

Retrospective Analysis of Onychomycosis Risk Factors Using the 2003-2014 National Inpatient Sample

INTRODUCTION

Onychomycosis, a fungal nail infection, is associated with significant morbidity and negative impact on quality of life. Therefore, understanding associated risk factors may inform onychomycosis screening guidelines.

OBJECTIVES

This retrospective study investigated common demographic and comorbidity risk factors among hospitalized patients using the National Inpatient Sample.

METHODS

The 2003-2014 National Inpatient Sample (NIS) database was used to identify onychomycosis cases and age and sex matched controls in a 1:2 ratio. Chi-square tests and T-tests for independent samples were utilized to compare categorical and continuous patient factors. Demographic and comorbidity variables significant (P < 0.05) on univariate analysis were analyzed via a multivariate regression model with Bonferroni correction (P < 0.0029).

RESULTS

119,662 onychomycosis cases and 239,324 controls were identified. Compared to controls, onychomycosis patients frequently were White (69.0% versus 68.0%; P < 0.001), Black (17.9% versus 5.8%; P < 0.0001), and insured by Medicare or Medicaid (80.1% versus 71.1%; P < 0.0001). Patients had greater hospital stays (9.69 versus 5.39 days; P < 0.0001) and costs ($39,925 versus $36,720; P < 0.001) compared to controls. On multivariate analysis, onychomycosis was commonly associated with tinea pedis (odds ratio [OR]: 111.993; P < 0.0001), human immunodeficiency virus (OR: 4.372; P < 0.001), venous insufficiency (OR: 6.916; P < 0.0001), and psoriasis (OR: 3.668; P < 0.001).

CONCLUSIONS

Onychomycosis patients had longer hospital stays and greater costs compared to controls. Black patients were disproportionately represented among cases compared to controls. Onychomycosis was associated with tinea pedis, venous insufficiency, human immunodeficiency virus, psoriasis, obesity (body mass index [BMI] ≥ 30 kg/m2), peripheral vascular disease, and diabetes with chronic complications, suggesting that inpatients with onychomycosis should be screened for these conditions.

Treatment Options for Onychomycosis: Efficacy, Side Effects, Adherence, Financial Considerations, and Ethics

Background

Onychomycosis is a fungal infection of the nail unit that affects a large patient population globally. Onychomycosis, or tinea unguium, has a benign chronic clinical course; however, it can cause complications in certain patient populations suffering from diabetes and peripheral vascular disease. As nails grow slowly, onychomycosis requires a lengthy treatment plan, and choosing appropriate treatments can be challenging. There are a variety of treatment modalities available for patients including topical, oral, laser, light therapy, procedures such as avulsion and matrixectomy, supplements, over-the-counter medication, and plasma therapy that can be used as monotherapy or in combination for patient satisfaction.

Objective

We sought to review treatment options for onychomycosis, taking into consideration the efficacy, side effect profiles, practicality of treatment (adherence), and costs to help healthcare providers offer ethically appropriate treatment regimens to their patients.

Methods

A literature search was conducted using electronic databases (PubMed, Embase, Medline, CINAHL, EBSCO) and textbooks, in addition to the clinical experiences of the authors and other practitioners in treating onychomycosis, and a summary of the findings are presented here.

Results

Although topical (efinaconazole, tavaborole, ciclopirox), oral (terbinafine, itraconazole), and laser (1064nm Nd:YAG lasers, both short-pulsed and Q-switched lasers, carbon dioxide lasers, and the diode 870, 930nm) are the current Food and Drug Administration (FDA)-approved treatments for onychomycosis, they are just a fraction of available treatment options. New and emerging therapies including new topical and oral medications, combination therapy, photodynamic light therapy, procedural, supplements, over-the-counter medication, and plasma therapy are discussed in our review.

Discussion

Onychomycosis has high reinfection and recurrence rates, and the treatment remains challenging as treatment selection involves ethical, evidence-based decision-making and consideration of each individual patient's needs, adherence, budget, the extent of quality of life discomfort, and aesthetic goals, independent of potential financial benefits to the clinicians.

Toenail Onychomycosis with or without Diabetes in Canada: Patient Treatment Preferences and Health State Utilities

Background

Toenail onychomycosis affects approximately 6.7% of Canadians. Symptoms include nail discolouration/disfiguration and pain; psychosocial impacts contribute to reduced health-related quality-of-life. Comorbid diabetes increases the risk of complications and exacerbates burden. Treatment may include topical therapy and/or oral agents.

Purpose

To understand toenail onychomycosis treatment preferences, and to quantify the impact of toenail onychomycosis, with or without diabetes, on patient well-being.

Methods

Adults living in Canada with self-reported, physician-diagnosed, toenail onychomycosis were recruited online. A discrete choice experiment was used to quantify treatment preferences. Scenarios were randomized; data were analyzed using conditional logit regression. Health state utilities were estimated using the Health Utilities Index Mark 3®. Results were stratified by diabetes status and toenail onychomycosis severity; the Wilcoxon Rank Sum test was used to assess between-group utility differences.

Results

Three-hundred thirteen participants with toenail onychomycosis were included (161 had comorbid diabetes; 61.3%, severe onychomycosis). The mean age was 57.7 years; 55.9% were male. Treatment attributes with statistically significant impacts on patient preferences were efficacy (odds ratio [OR],1.04; 95% confidence interval [CI], 1.02-1.05 per 1% increased treatment success), administration method (one pill versus topical nail lacquer reference, 1.14; 1.04-1.26; topical solution applicator versus reference: 1.15; 1.03-1.29), severe adverse events (0.85; 0.80-0.90 per 1% increased risk), and risk of potential pharmacodynamic (0.80; 0.76-0.85) and alcohol (0.93; 0.88-0.98) interactions; preferences were more pronounced for efficacy and avoiding severe adverse events among toenail onychomycosis patients with comorbid diabetes. The mean (95% CI) utility value was 0.73 (0.70-0.75) overall, and statistically significantly lower (p=0.02) for toenail onychomycosis patients with diabetes (0.70; CI, 0.66-0.73) than those without (0.76; CI, 0.72-0.79).

Conclusion

Among patients with toenail onychomycosis, the presence of diabetes was associated with differing treatment-related preferences. Utility values for patients with toenail onychomycosis represent a significant decline from full health that is exacerbated by comorbid diabetes.

Morphological and ultrastructural changes in fungal agents after LASER application

BACKGROUND

Onychomycosis is a fungal nail infection of difficult treatment due to the fungal survival capacity and reduced number of effective therapies. The present study aimed to isolate fungal agents that cause onychomycosis in immunocompetent patients and evaluate how LASER treatments affect the growth and ultrastructure of isolates.

METHODS

In total, 21 patients with positive direct microscopic examination (DME) for onychomycosis had nail samples collected for cultivation and phenotypic identification of microorganisms. From these patients, 12 underwent LASER treatment, divided in Group 1 (n = 5) treated with Nd: YAG 1,064 nm, and Group 2 (n = 7) treated with Nd: YAG 1,064 nm + Er: YAG 2,940 nm + topical isoconazole. Transmission Electron Microscopy (TEM) was performed to evaluate ultrastructural changes after treatment.

RESULTS

DME, cultivation, and phenotypic identification showed that the most identified fungus was Trichophyton rubrum spp. After LASER therapy, sample cultivation showed alterations in the fungal morphology with reduction of hyphae, conidia, and reproductive structures. Alterations in fungal cell wall structure, cytoplasm density, and organelles were observed by TEM.

CONCLUSION

LASER irradiation causes changes in the fungal cells, especially in the number of hyphae and the presence of conidia. In addition, it affects fungal growth and reproduction capacity, which interferes with their infection ability and virulence.

New Formulation-Microporation Combination Approaches to Delivering Ciclopirox across Human Nails

Topical treatments for onychomycosis are of interest to those seeking to avoid systemic drug interactions and to improve systemic safety. This work aimed to develop aqueous-based, simple, and cost-effective vehicles that provide high solubility for ciclopirox and enable the delivery of an active through channels created by nail microporation. Following solubility tests, aqueous gels and thermogels based on hydroxypropylmethylcellulose and poloxamer 407, respectively, were loaded with 8% and 16% ciclopirox. Their performance was then compared to the marketed lacquer Micolamina® in in vitro release tests with artificial membranes and in in vitro permeation tests with human nail clippings with and without poration. Finally, a microbiological assay compared the best gel formulations and the reference product. Little correlation was observed between the in vitro release and the permeation data, and the drug release was highly membrane-dependent. Ciclopirox nail retention in single-dose, porated nails tests was larger than in daily-dosing, non-porated nail conditions. The series of new gel and thermogel vehicles delivered ciclopirox more effectively than Micolamina® in single-dose, porated nail experiments. The inhibition of Trichophyton rubrum activity was significantly increased with microporated nails when the gel formulations were applied but not with Micolamina®. Overall, the results suggest that the new vehicles could be successfully combined with nail microporation to improve the drug delivery and efficacy of topical antifungal medication while reducing the dosing frequency, facilitating patients' adherence.

Recent drug development and treatments for fungal infections

Fungal infections are now becoming a hazard to individuals which has paved the way for research to expand the therapeutic options available. Recent advances in drug design and compound screening have also increased the pace of the development of antifungal drugs. Although several novel potential molecules are reported, those discoveries have yet to be translated from bench to bedside. Polyenes, azoles, echinocandins, and flucytosine are among the few antifungal agents that are available for the treatment of fungal infections, but such conventional therapies show certain limitations like toxicity, drug interactions, and the development of resistance which limits the utility of existing antifungals, contributing to significant mortality and morbidity. This review article focuses on the existing therapies, the challenges associated with them, and the development of new therapies, including the ongoing and recent clinical trials, for the treatment of fungal infections. Advancements in antifungal treatment: a graphical overview of drug development, adverse effects, and future prospects.

Contemporary Techniques and Potential Transungual Drug Delivery Nanosystems for The Treatment of Onychomycosis

The humanoid nail is considered an exceptional protective barrier that is formed mainly from keratin. Onychomycosis is the cause of 50% of nail infections that is generally caused by dermatophytes. Firstly, the infection was regarded as a cosmetic problem but because of the tenacious nature of onychomycosis and its relapses, these infections have attracted medical attention. The first line of therapy was the oral antifungal agents which were proven to be effective; nevertheless, they exhibited hepato-toxic side effects, alongside drug interactions. Following, the opportunity was shifted to the topical remedies, as onychomycosis is rather superficial, yet this route is hindered by the keratinized layers in the nail plate. A potential alternative to overcome the obstacle was applying different mechanical, physical, and chemical methods to boost the penetration of drugs through the nail plate. Unfortunately, these methods might be expensive, require an expert to be completed, or even be followed by pain or more serious side effects. Furthermore, topical formulations such as nail lacquers and patches do not provide enough sustaining effects. Recently, newer therapies such as nanovesicles, nanoparticles, and nanoemulsions have emerged for the treatment of onychomycosis that provided effective treatment with possibly no side effects. This review states the treatment strategies such as mechanical, physical, and chemical methods, and highlights various innovative dosage forms and nanosystems developed in the last 10 years with a focus on advanced findings regarding formulation systems. Furthermore, it demonstrates the natural bioactives and their formulation as nanosystems, and the most relevant clinical outcomes.

Antifungal effect of (R) and (S)-citronellal enantiomers and their predictive mechanism of action on Candida albicans from voriconazole-resistant onychomycoses

Onychomycosis is the most common disease affecting the nail unit and accounts for at least 50% of all nail diseases. In addition, Candida albicans is responsible for approximately 70% of onychomycoses caused by yeasts. This study investigated the antifungal effect of (R) and (S)-citronellal enantiomers, as well as its predictive mechanism of action on C. albicans from voriconazole-resistant onychomycoses. For this purpose, in vitro broth microdilution and molecular docking techniques were applied in a predictive and complementary manner to the mechanisms of action. The main results of this study indicate that C. albicans was resistant to voriconazole and sensitive to the enantiomers (R) and (S)-citronellal at a dose of 256 and 32 µg/mL respectively. In addition, there was an increase in the minimum inhibitory concentration (MIC) of the enantiomers in the presence of sorbitol and ergosterol, indicating that these molecules possibly affect the integrity of the cell wall and cell membrane of C. albicans. Molecular docking with key biosynthesis proteins and maintenance of the fungal cell wall and plasma membrane demonstrated the possibility of (R) and (S)-citronellal interacting with two important enzymes: 1,3-β-glucan synthase and lanosterol 14α-demethylase. Therefore, the findings of this study indicate that the (R) and (S)-citronellal enantiomers are fungicidal on C. albicans from onychomycoses and probably these substances cause damage to the cell wall and cell membrane of these micro-organisms possibly by interacting with enzymes in the biosynthesis of these fungal structures.

A Review of Antifungal Susceptibility Testing for Dermatophyte Fungi and It's Correlation with Previous Exposure and Clinical Responses

Background: An increase in the number of recurrent and recalcitrant dermatophytoses calls for a tool to guide the clinician to correlate in vitro minimum inhibitory concentration (MIC) data, antifungal treatment with clinical outcomes. This systematic review aims to explore a possible correlation between one aspect of this, previous antifungal exposure, and clinical outcomes. Methods: A systematic literature search for articles on previous antifungal treatment, treatment outcome, susceptibility methods used, organism (genus/species), and MIC values was conducted. Results: A total of 720 records were identified of which 19 articles met the inclusion criteria. Forty percent of the cases had contact with or travel to India, 28% originated from or had traveled to other countries where treatment unresponsive tinea infections had been reported. Tinea corporis was the most common clinical presentation and the species involved were Trichophyton (T.) indotineae and T. rubrum, followed by T. mentagrophyte/interdigitale complex and T. tonsurans. Nearly all patients had previously been exposed to one or more antifungals. The studies were too heterogeneous to perform a statistical analysis to test if previous antifungal exposure was related to resistance. Conclusions: Only a few studies were identified, which had both sufficient and robust data on in vitro susceptibility testing and clinical treatment failure. Further research on the value of susceptibility testing to improve clinical practice in the management of dermatophyte infections is needed.

Fractional CO2 laser - assisted methylene blue photodynamic therapy is a potential alternative therapy for onychomycosis in the era of antifungal resistance

BACKGROUND

Treatment of onychomycosis is challenging by virtue of the impact of nail disfigurement, the location of the fungi within the nail and reported antifungal resistance worldwide. Light-based technologies are promising primary or adjunctive therapeutic modalities. We aimed to compare the efficacy of photodynamic therapy and fractional CO2 laser monotherapy either alone or in combination for onychomycosis.

PATIENTS AND METHODS

This prospective randomized comparative study was conducted on 51 onychomycosis patients divided into three groups. In group A, patients were treated using 6 photodynamic therapy sessions using methylene blue and IPL (560 to 700 nm, fluence 12 J/cm2). Group B patients were treated using 6 bimonthly fractional CO2 laser sessions (10,600 nm, 1.600 mj energy and 0.6 mm density) and group C patients were treated using 6 combined fractional CO2 laser and photodynamic therapy sessions. Patients were evaluated mycologically, dermoscopically and clinically by calculation of proximal nail diameter percentage at baseline, monthly, at the end of treatment and after a 6-month follow-up period post-treatment.

RESULTS

Candida was the most commonly isolated organismin in 64.7%, 70.6% and 70.6% of the pateints in groups A, B and C, respectively. The dermoscopic findings in the total dystrophic onychomycosis was subungual hyperkeratosis in 6 patients (100%), longitudinal streaks and striae in 1 patient (16.7%). In dorsolateral subungual onychomycosis, jagged proximal edge in 31 patients (70.5%), and pigmentation in 30 patients (68.2%) were noted. In proximal subungual onychomycosis irregular matt patches were seen in 1 patient (100%). Proximal nail diameter percentage showed statistically significant improvement after treatment and 6 months follow up in the 3 studied groups. Mean increase of proximal nail diameter after treatment was highest in group C (52.94 ± 20.24), followed by group B (43.82 ± 21.03) and least in group A (35.29 ± 17.0). This difference was statistically significant (p = 0.044). Reported side effects were mild-moderate pain, discoloration and paronychia.

CONCLUSION

We conclude that fractional CO2 laser and photodynamic monotherapy, and their combination achieve high success rates, good patient satisfaction and safety profile. Fractional CO2-assisted photodynamic therapy is associated with the highest improvement over either fractional CO2 or photodynamic therapy alone.

Onychomycosis: Recommendations for Diagnosis, Assessment of Treatment Efficacy, and Specialist Referral. The CONSONANCE Consensus Project

Introduction

Onychomycosis is the most common nail disorder in adults, with high recurrence and relapse rates. Its diagnosis may be difficult by non-experts because the clinical signs may overlap with other dermatoses. The treatment may be challenging, as it should be patient-tailored.

Methods

An online survey was conducted among European Nail Society (ENS) members to provide recommendations on the diagnosis and assessment of distal lateral subungual onychomycosis (DLSO) in non-specialized clinical environments, as well as recommendations for patient referral.

Results

DLSO diagnosis is predominantly based on clinical aspects, and microscopy and fungal culture are commonly employed to establish the diagnosis. Assessment of clinical features is the main method for DLSO follow-up, and the main criterion to define cure is a combination of mycologic cure and clinical cure. The most commonly selected treatments for onychomycosis include oral antifungals, topical antifungals, and nail debridement. According to the nail experts, predisposing factors of DLSO to be evaluated include concurrent tinea pedis diagnosis, immunocompromised status, and diabetes. The minimum clinical aspects to be evaluated for DLSO diagnosis should include subungual hyperkeratosis, white-yellow-orange subungual scales, and absence of salmon-pink coloration. Recommendations for clinical signs that should be evaluated to confirm treatment effectiveness include normal appearance and color of the nail, reduction or absence of scales under the nail, and absence of onycholysis. Recommendations for specialist referral include lack of treatment effectiveness, need of additional therapies, concurrent presence of other diseases or comorbidities, severe DLSO, and presence of a dermatophytoma or involvement of the nail matrix.

Conclusions

According to the surveyed nail experts, after evaluating clinical signs and predisposing factors for DLSO, the diagnosis should include subungual hyperkeratosis, nail color (yellow-orange), and onycholysis and thickening. In cases of severe DLSO, when there is treatment failure, concomitant diseases/comorbidities, presence of a dermatophytoma or involvement of the nail matrix, or involvement of several/all nails, referral should be considered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-022-00698-x.

MOLECULAR DETECTION OF THE TWO VIRULENCE GENES HWP1 AND ALS1 IN CANDIDA SPECIES ISOLATED FROM ONYCHOMYCOSIS

OBJECTIVE

The aim: This article was aimed to assess the prevalence of Candida species causing nail infections and to investigate the most important virulence genes that cause adhesion.

PATIENTS AND METHODS

Materials and methods: Samples were collected from General Hospital and the outpatient's clinics in Thi-Qar Province, southern Iraq, during the period from January 2021 to May 2021. Samples were inoculated on Sabouraud Dextrose Agar plates containing 0.5 mg chloramphenicol, then Petri dishes were incubated at 30°C under aerobic conditions and observed for Candida species growth for 24-72 hrs. All isolates were identified by morphologic and chromatic properties on CHROMagar and by Api Candida.

RESULTS

Results: Twenty five isolates were obtained from hundred samples, which belong to five species of the genus Candida, distributed in percentage 9(36%), 4(16%), 4(16%), 4(16%) and 3(12%) of C. glabrata, C. krusei, C. albicans, C. famata and C. tropicalis consecutively and one isolate was not identified. Monoplex PCR technique was used to detect virulence genes (hwp1 and als1) of Candida species. Four Candida albicans isolates (16%) were carried of both hwp1 and als1 genes.

CONCLUSION

Conclusions: The virulence gene (hwp1) can be relied upon in molecular detection as a special diagnostic tool of Candida albicans species except other types causing Candidal onychomycosis.

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.

Apiaceae Essential Oils: Boosters of Terbinafine Activity against Dermatophytes and Potent Anti-Inflammatory Effectors

Dermatophyte infections represent an important public health concern, affecting up to 25% of the world's population. Trichophyton rubrum and T. mentagrophytes are the predominant dermatophytes in cutaneous infections, with a prevalence accounting for 70% of dermatophytoses. Although terbinafine represents the preferred treatment, its clinical use is hampered by side effects, drug-drug interactions, and the emergence of resistant clinical isolates. Combination therapy, associating terbinafine and essential oils (EOs), represents a promising strategy in the treatment of dermatophytosis. In this study, we screened the potential of selected Apiaceae EOs (ajowan, coriander, caraway, and anise) to improve the antifungal activity of terbinafine against T. rubrum ATCC 28188 and T. mentagrophytes ATCC 9533. The chemical profile of EOs was analyzed by gas chromatography. The minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of EOs/main compounds were determined according to EUCAST-AFST guidelines, with minor modifications. The checkerboard microtiter method was used to identify putative synergistic combinations of EOs/main constituents with terbinafine. The influence of EOs on the viability and pro-inflammatory cytokine production (IL-1β, IL-8 and TNF-α) was determined using an ex vivo human neutrophils model. The binary associations of tested EOs with terbinafine were found to be synergistic against T. rubrum, with FICI values of 0.26-0.31. At the tested concentrations (6.25-25 mg/L), EOs did not exert cytotoxic effects towards human neutrophils. Anise EO was the most potent inhibitor of IL-1β release (46.49% inhibition at 25 mg/L), while coriander EO displayed the highest inhibition towards IL-8 and TNF-α production (54.15% and 54.91%, respectively). In conclusion, the synergistic combinations of terbinafine and investigated Apiaceae EOs could be a starting point in the development of novel topical therapies against T. rubrum-related dermatophytosis.

Molecular characterization and antifungal activity against non-dermatophyte molds causing onychomycosis

Onychomycosis is a fungal disease that caused by different types of fungi. Non-dermatophyte molds are a large saprophytic fungi group that live in nature and could affect traumatic nails. The aim of this study was to identify non-dermatophyte molds causing onychomycosis and evaluation of several antifungal activities against the isolates. The samples consisted of 50 non-dermatophyte molds isolated from patients with onychomycosis confirmed by direct and culture examination fungal. DNA was extracted, amplified, and sequenced. Disk diffusion method was used to evaluate itraconazole, fluconazole, ketoconazole, terbinafine, posaconazole, and econazole activity against the isolates. The species identified as: Aspergillus flavus 22 (44%), A. niger 12 (24%), A. fumigates, 3 (6%), A. sydowii 3 (6%), A. terreus 1 (2%), Penicillium commune 2 (4%), P. glabrum 2 (4%), P. chrysogenum, 1 (2%), Fusarium solani 3 (6%) and F. thapsinum 1 (2%). Most of the samples were sensitive to terbinafine, itraconazole, and econazole and 94% of the isolates were resistant to fluconazole. This study showed that Aspergillus species were the most common cause of non-dermatophyte mold onychomycosis and fluconazole was the most resistant antifungals. Care must be taken to choose the appropriate antifungal drug for a better cure.

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.

Candida guilliermondii Onychomycosis Involving Fingernails in a Breast Cancer Patient under Docetaxel Chemotherapy

Onychomycosis has been shown to have a higher incidence in cancer patients. Nail toxicity is a quite common side effect of anticancer agents. Taxotere© is a chemotherapeutic known to cause great incidence of nail change and has a role in subungual suppuration. We report on a 52-year-old woman with breast cancer admitted in our institution for onycholysis. Because of the stage and histology of breast cancer, neoadjuvant chemotherapy was initiated. The patient received 8 cycles of Taxotere and Adriamycin (AT), and she underwent a modified radical mastectomy. Three months later, the patient developed evidence of onycholysis, involving all the fingernails. We observed the following changes in nails of all the digits in both hands: onycholysis, dystrophy, oedema, and exudate. Nail scraping and purulent discharge were collected and cultured on Sabouraud medium. Physical features of the colonies and biochemical tests (Auxacolor©) revealed Candida guilliermondii as the sole etiologic agent of onychomycosis. This case details an onycholysis in a breast cancer case successfully managed solely with amorolfine lacquer. This clinical and mycological presentation should alert the clinician to the possibility of onychomycosis induced by docetaxel chemotherapy.

One size does not fit all: the need for individualized treatment based on factors that may affect the therapeutic outcome of efinaconazole 10% solution for the treatment of toenail onychomycosis

Successful management of onychomycosis is a challenge because cure rates with most antifungals are relatively low and recurrence rates are high. A drug-based approach by treating the nail alone may not suffice. There are several host-related factors (age, sex, body mass index [BMI], and patient's quality of life), disease-related factors (disease severity, duration, and the number of toenails affected), and comorbidities (tinea pedis and diabetes) that may affect treatment efficacy. Here, we review the post hoc analyses of the phase III trials of efinaconazole 10% solution that have investigated the impact of these factors on topical therapy for toenail onychomycosis. The significant clinical variables that may affect the efficacy of efinaconazole include sex, BMI, disease severity, disease duration, and tinea pedis. As older patients may have slower toenail growth and more severe, longstanding disease compared with younger patients, they may require longer treatment duration, beyond the 48-week standard regimen. Treatment compliance may need to be discussed for an improved health outcome. Therefore, these prognostic factors need to be carefully evaluated, which may aid in formulating individualized therapy to maximize treatment success.

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.

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.

Ciclopirox Hydroxypropyl Chitosan (HPCH) Nail Lacquer: A Review of Its Use in Onychomycosis

Ciclopirox 8% hydroxypropyl chitosan (HPCH) [Marketed in different countries as the following registered (®) brands: Ciclopoli, Fulcare, Kitonail, Myconail, Niogermos, Niogermox, Onytec, Ony-Tec, Polinail, Privex, Rejuvenail] is the first topical nail lacquer developed using innovative drug formulation technology. It is indicated for the treatment of mild-to-moderate fungal infections of the nails that are caused by dermatophytes and/or other ciclopirox-sensitive fungi, without nail matrix involvement. HPCH is a patented drug formulation technology for the delivery of active principles into the nails based on a hydrosoluble semisynthetic amino-polysaccharide biopolymer derivative of chitosan. The lacquer acts as a protective barrier against microbiological attack, physical damage and/or aggressive chemicals. Results from in vitro studies suggest that the application of ciclopirox 8% HPCH nail lacquer improves drug permeation into and/or drug penetration through the nail, relative to the water-insoluble ciclopirox 8%, amorolfine 5% and efinaconazole 10% reference lacquers. In addition, in vitro and clinical studies in healthy subjects found that the concentration of ciclopirox reached in subungual fluids after application of ciclopirox 8% HPCH was sufficient for inhibiting fungal growth. In clinical studies in patients with mild-to-moderate onychomycosis, ciclopirox 8% HPCH was found to be more effective than the commercial water-insoluble ciclopirox 8% and amorolfine 5% lacquers, as indicated by higher complete cure, response and mycological cure rates at 48 weeks after treatment initiation. Ciclopirox 8% HPCH has been found to be generally well tolerated, with no treatment-related adverse events reported in patients using this nail lacquer. Thus, current evidence indicates that ciclopirox 8% HPCH represents a valuable treatment option for the treatment of patients with onychomycosis.

Potential of Naftifine Application for Transungual Delivery

Naftifine is used to treat fungal skin infections as it inhibits dermatophytes, which are the cause of onychomycosis. However, naftifine's ability to permeate the human nail barrier has not been investigated, thus, the antimycotic potential is not clearly established. This work aims to evaluate the effect of penetration enhancing factors on the accumulation of naftifine hydrochloride through human nail clippings. Naftifine polymeric nail lacquers with Eudragit RL100 were developed as a suitable delivery system. Low penetration of naftifine into nail has been determined as less than 10% of applied drug dose accumulated in the nail layers. Incorporation of thioglycolic acid into formulations resulted in increased accumulation of antifungal agent in the nail layers by 100% compared with a control group. Salicylic acid did not effect naftifine accumulation in the human nail. The permeation of naftifine through the nail increased by threefold when the thioglycolic acid-containing formulation was applied and the nail was pretreated with a fractional CO2 laser. Structural changes of the nail barrier, induced by fractional CO2 laser, were visualized by microscopy. The results suggest, that naftifine nail penetration could be significantly increased when physical and chemical enhancing factors are applied.

Clinical Evaluation of a Topical Formulation for the Management of Onychomycosis

BACKGROUND: Onychomycosis is a diffused fungal-associated disease affecting the nails. It induces discoloration, dystrophy, and, in the most severe cases, nail detachment. No completely effective pharmacological cures are available for onychomycosis. Available treatment options usually require a long-term treatment period and might raise safety concerns. OBJECTIVE: The aim of this preliminary clinical study is to evaluate the efficacy of Myco Clear® (MC) in improving the structural integrity and appearance of nails affected by mild onychomycosis. MC is a topical product to be applied on the nails either for onychomycosis treatment or for the prevention of fungal nail infections. Its main action is the formation of a mechanic protective barrier on the nail surface, which protects the damaged nail structure from additional external aggressions and prevents further pathogen penetration. METHODS: This monocentric, single-arm investigation enrolled 30 subjects with damaged nails on the feet. Patients were asked to apply the product once a day for 56 consecutive days; the instrumental analysis of nail roughness was obtained after seven, 14, 28, and 56 days of product application. In addition, the clinical evaluation of nail integrity and hardness were performed at baseline and after seven, 14, 28 and 56 days. RESULTS: The obtained data were statistically evaluated in comparison to baseline. MC treatment significantly promoted a restoration of the nail structure and an improvement in its appearance; furthermore, no adverse events were reported, thus demonstrating that MC is optimally tolerated. CONCLUSION: The results of this pilot study suggest that MC is effective in improving the overall appearance and structural integrity of damaged nails affected by possible mild onychomycosis.

Activity of Metal-Azole Complexes Against Biofilms of Candida albicans and Candida glabrata

Background:

Onychomycosis is a chronic nail infection caused by fungi frequently resistant to antifungal treatments. Recalcitrance in nail infections is a result of reduced antifungal penetration due to biofilm formation, combined with poor patient compliance with the treatment, which can be as long as 18 months.

Objective:

Metal-drug complexation is a widely used strategy to increase drug efficacy. Therefore, the aim of this work was to evaluate the antifungal and anti-biofilm activity of several metal-azole complexes against Candida albicans and Candida glabrata.

Methods:

Susceptibility assays and scanning electron microscopy were performed to determine the anti-biofilm activity of eight metal-azole complexes in vitro and ex-vivo, using human nail fragments.

Results:

In vitro susceptibility assays showed that complexation of both Au(I) and Zn(II) to clotrimazole and ketoconazole improved the anti-biofilm activity compared to the azole alone. Using an ex-vivo model of biofilm formation on fragments of human nails, we also demonstrate the improved efficacy of metal-azole complexes against biofilms of C. albicans and C. glabrata that resembles the onychomycosis structure. Noteworthy, biofilms of C. glabrata were more susceptible to the optimized complexes than those of C. albicans.

Conclusion:

In conclusion, metal-azole complexes used in this work show promising anti-biofilm activity and further clinical studies should confirm its potential for the treatment of Candida-associated onychomycosis.

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.

Semisynthetic eugenol derivatives as antifungal agents against dermatophytes of the genus Trichophyton

PURPOSE

Eugenol, the main component of clove bud essential oil (Eugenia caryophyllus), has been linked to antimicrobial, anti-inflammatory, insecticidal and immunomodulatory properties. The purpose of this study was to evaluate the antifungal and cytotoxic activity of eugenol, the essential oil of Eugenia caryophyllus, and some semisynthetic derivatives of eugenol against dermatophytes of the genus Trichophyton.

METHODOLOGY

We evaluated the antifungal effect of the compounds, determining the minimum inhibitory concentrations (MICs) by the microdilution method and the minimum fungicidal concentrations by cultures from the inhibitions. Additionally, the inhibition of the radial growth of the mycelium of the dermatophyte fungi was tested by poisoned substrate. Cytotoxicity was measured by the colorimetric method on Vero cells.

RESULTS

All of the eugenol compounds tested exhibited antifungal properties, showing MICs of 62.5-500 µg ml^-1 , determined within three dermatophyte species: Trichophyton rubrum, Trichophyton mentagrophytes and Trichophyton tonsurans. Among these derivatives, methyl isoeugenol, at concentrations of 300 and 100 µg ml^-1, was found to completely inhibit (100 %) radial growth of the mycelium of all three species after 20 days of treatment. Additionally, phenotypic variations related to the decrease in pigment production of T. rubrum were observed after treatment with O-ethyl and O-butyl isoeugenol derivatives. Meanwhile, all of the tested (iso)eugenol molecules exhibited moderate toxicity in Vero cells [50 % cytotoxic concentration (the concentration required for a 50 % reduction in cell viability; CC50): 54.06-265.18 µg ml^-1 ).

CONCLUSION

The results suggest that the semisynthetic eugenol derivatives (SEDs) show promising antifungal activity and selectivity against dermatophyte fungi.