Pharmacotherapy for onychomycosis: new and emerging treatments

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.

Retrospective analysis of onychomycosis prescribing patterns using the medicare part D prescribers database 2016-2020

Onychomycosis, defined as a fungal nail infection, affects 5.5% of the global population. Our objectives were to analyse prescription trends of onychomycosis medications using the Medicare Part D Prescribers database from 2016 to 2020, stratified by physician specialty. There was a 4% annual increase in the total cost of onychomycosis medications, with a notable decrease of 12.8% in 2020 during the COVID-19 pandemic. Physicians demonstrated a strong consideration for price when selecting treatments, with the least expensive medications (ciclopirox and terbinafine) accounting for nearly 99% of all prescriptions. In contrast, the more costly medications (efinaconazole and tavaborole) were rarely prescribed. In addition, physicians often opted for the less costly generic versions of ciclopirox and itraconazole, prescribing them 99% and 91% of the time, respectively. Notably, physician assistants and nurse practitioners had higher overall increases in prescription rates, at 15%, compared to 1%-6% for other specialties. There are no recent United States onychomycosis guidelines, and our study emphasizes cost considerations when prescribing onychomycosis treatments.

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.

Updated Perspectives on the Diagnosis and Management of Onychomycosis

Onychomycosis is the most common nail disease encountered in clinical practice and can cause pain, difficulty with ambulation, and psycho-social problems. A thorough history and physical examination, including dermoscopy, should be performed for each patient presenting with nail findings suggestive of onychomycosis. Several approaches are available for definitive diagnostic testing, including potassium hydroxide and microscopy, fungal culture, histopathology, polymerase chain reaction, or a combination of techniques. Confirmatory testing should be performed for each patient prior to initiating any antifungal therapies. There are several different therapeutic options available, including oral and topical medications as well as device-based treatments. Oral antifungals are generally recommended for moderate to severe onychomycosis and have higher cure rates, while topical antifungals are recommended for mild to moderate disease and have more favorable safety profiles. Oral terbinafine, itraconazole, and griseofulvin and topical ciclopirox 8% nail lacquer, efinaconazole 10% solution, and tavaborole 5% solution are approved by the Food and Drug Administration for treatment of onychomycosis in the United States and amorolfine 5% nail lacquer is approved in Europe. Laser treatment is approved in the United States for temporary increases in clear nail, but clinical results are suboptimal. Oral fluconazole is not approved in the United States for onychomycosis treatment, but is frequently used off-label with good efficacy. Several novel oral, topical, and over-the-counter therapies are currently under investigation. Physicians should consider the disease severity, infecting pathogen, medication safety, efficacy and cost, and patient age, comorbidities, medication history, and likelihood of compliance when determining management plans. Onychomycosis is a chronic disease with high recurrence rates and patients should be counseled on an appropriate plan to minimize recurrence risk following effective antifungal therapy.

In Vitro Activity of Ebselen and Diphenyl Diselenide Alone and in Combination with Drugs against Trichophyton mentagrophytes Strains

Background: Dermatophytoses are one of the most prevalent infectious diseases in the world for which the pace of developing new drugs has not kept pace with the observed therapeutic problems. Thus, searching for new antifungals with an alternative and novel mechanism of action is necessary. Objective: This study aimed to evaluate the antifungal activity of ebselen and diphenyl diselenide against Trichophyton mentagrophytes clinical isolates. Methods: In vitro antifungal susceptibility was assessed for organoselenium compounds used alone or in combination with allylamines and azoles according to the 3rd edition of the CLSI M38 protocol. Results: Ebselen demonstrated high antifungal activity with MIC_GM equal to 0.442 μg/mL and 0.518 μg/mL in the case of human and animal origin strains, respectively. The values of MIC_GM of diphenyl diselenide were higher: 17.36 μg/mL and 13.45 μg/mL for the human and animal isolates, respectively. Synergistic or additive effects between terbinafine and ebselen or diphenyl diselenide were observed in the case of 12% and 20% strains, respectively. In turn, the combination of itraconazole with diphenyl diselenide showed a synergistic effect only in the case of 6% of the tested strains, whereas no synergism was shown in the combination with ebselen. Conclusions: The results highlight the promising activity of organoselenium compounds against Trichophyton mentagrophytes. However, their use in combinational therapy with antifungal drugs seems to be unjustified due to the weak synergistic effect observed.

Development and Validation of HPLC Method for Efinaconazole: Application to Human Nail Permeation Studies

Efinaconazole is the first azole derivative approved by FDA for the topical treatment of onychomycosis. The objective of present study was to develop and validate HPLC method for estimation of efinaconazole in ex vivo human nail permeation study samples. The chromatographic analysis was performed on a HPLC system equipped with diode array detector. The efinaconazole and internal standard (IS) were extracted from the human nail samples by using the protein precipitation method. The samples were injected on to 5 μm Polar C₁₈ 100Å, 4.6 mm × 150 mm column. The mobile phase consisted of 0.01 M potassium dihydrogen phosphate: acetonitrile (36:64) and eluent was monitored at 205 nm. The chromatographic separation of drug and analyte was achieved using isocratic elution at flow rate of 1 mL/min with a total run time of 15 min. The efinaconazole and IS were eluted at 6.4 ± 0.5 and 8.3 ± 0.5 min, respectively. The developed method was validated as per FDA guidelines, and the results met with acceptance criteria. The method developed was specific, and the analyte concentrations were linear at range of 50 to 10000 ng/mL (R² ≥ 0.9981). The validated HPLC method was applied for quantifying efinaconazole in human nail permeation study samples. The permeation of efinaconazole was increased by twofolds with Labarfac CC (15135.4 ± 2233.9 ng/cm²) compared to formulations containing Transcutol P (6892.0 ± 557.6 ng/cm²) and Labrasol (7266.1 ± 790.6 ng/cm²). The study results demonstrate that developed efinaconazole HPLC method can be employed for formulation evaluation and clinical studies.

A multicentre, randomised, parallel-group, double-blind, vehicle-controlled and open label versus amorolfine 5% study, to evaluate the efficacy and safety of terbinafine 10% nail lacquer in the treatment of onychomycosis

BACKGROUND

Onychomycosis is a difficult-to-treat fungal nail infection whose treatment can involve systemic or topical antifungal approaches.

OBJECTIVES

To assess the efficacy and safety of terbinafine 10% nail lacquer in distal lateral subungual onychomycosis (DLSO).

PATIENTS/METHODS

Patients with mild-to-moderate DLSO were randomised (3:3:1) to receive double-blind topical terbinafine 10% (n = 406) or its vehicle (n = 410) administered once daily for 4 weeks and then once weekly for 44 weeks, or open-label topical amorolfine 5% (n = 137) for 48 weeks, with a 12-week follow-up period. The primary efficacy endpoint, complete cure rate at Week 60, was a composite of negative potassium hydroxide (KOH) microscopy, negative culture for dermatophytes and no residual clinical involvement of the target big toenail.

RESULTS

Complete cure rates at Week 60 in the terbinafine, vehicle and amorolfine groups were 5.67%, 2.20% and 2.92%, respectively (odds ratio (OR) vs vehicle = 2.68; 95% confidence intervals (CI): 1.22-5.86; p = .0138). Statistically significant differences in responder (negative KOH and negative culture and ≤10% residual clinical involvement) and mycological cure rates (negative KOH and negative culture) at Week 60 were obtained between terbinafine and vehicle. Terbinafine was well-tolerated with no systemic adverse reactions identified; the most common topical adverse reactions were erythema and skin irritation.

CONCLUSIONS

Terbinafine 10% nail lacquer was an effective treatment for mild-to-moderate onychomycosis improving both clinical and mycological criteria compared with vehicle. Furthermore, there may be some benefits compared to the currently available topical agent, amorolfine 5%. Treatment was well-tolerated and safe.

Cold atmospheric pressure plasma (CAPP) as a new alternative treatment method for onychomycosis caused by Trichophyton verrucosum: in vitro studies

PURPOSE

Anthropophilic dermatophytes as etiological factors of onychomycoses are more common than zoophilic fungi. In the case of the latter, reverse zoonoses are possible, which poses a threat to the persistence of dermatophytes in the environment. Nevertheless, without treatment, both types of tinea unguium may lead to complete nail plate destruction and secondary mixed infections with fungi and bacteria. One of the zoophilic dermatophytes that cause onychomycosis is Trichophyton verrucosum, whose prevalence has been increasing in recent years. Such infections are usually treated with allylamines and/or azoles, but such a conventional treatment of infections caused by T. verrucosum often fails or is discontinued by patients.

METHODS

Herein, we reveal the results of our in vitro studies related to direct application of cold atmospheric pressure plasma (CAPP) on Trichophyton verrucosum growth, germination and adherence to nail as a new alternative treatment method of such types of dermatomycoses.

RESULTS

Our in vitro studies showed that, while exposure to CAPP for 10 min delays germination of conidia and clearly impairs the fitness of the fungal structures, 15 min is enough to kill all fungal elements exposed to plasma. Moreover, the SEM images revealed that T. verrucosum cultures exposed to CAPP for 10 and 15 min were not able to invade the nail fragments.

CONCLUSION

The results revealed that single exposure to CAPP was able to inhibit T. verrucosum growth and infection capacity. Hence, cold atmospheric pressure plasma should be considered as a promising alternative treatment of onychomycoses.

Tinea pedis-An embarrassing problem for health and beauty-A narrative review

Fungal infections present with a broad spectrum of diseases in humans (from relatively mild superficial infections of the skin and mucous membranes to the invasive or chronic infections of internal organs, which have a high mortality rate). Globally, up to 1.6 million people die each year as a result of various types of mycoses. Currently, many scientific studies focus on the best possible understanding of the aspects of the epidemiology and pathogenesis of invasive mycoses and effective methods to combat them. However, mycoses of the skin and its appendages remain a relatively less explored area. In some communities, superficial mycoses are a frequent problem as they affect nearly 70% of the population, an example of which is the athlete's foot. It involves the nails (onychomycosis) and skin (tinea pedis). It is mainly caused by keratin-decomposing dermatophyte fungi. Less often, infections are caused by non-dermatophyte moulds (Fusarium, Aspergillus, Scopulariopsis) or yeasts. Several factors have been listed as having substantial influence on the development of dermatophytosis, including those related to climate, season, geographical region, as well as to demography, socioeconomic and cultural customs, professions or contact with animals. In this review, we summarise the current knowledge about aetiology, epidemiology, diagnostics and therapy of tinea pedis with a special focus to the role of podologic management in spreading, prevention and therapy of mycoses. The article presents up-to-date knowledge on the management of the patient from the diagnosis, treatment and skincare, to counselling on how to prevent fungal skin infections in the long term.

Evaluation of activity and toxicity of combining clioquinol with ciclopirox and terbinafine in alternative models of dermatophytosis

Dermatophytosis is a superficial fungal infection that affects humans and is very common in small animals. The treatment using the most commonly used antifungals is failing, and new therapeutic alternatives are required to combat the resistance of these fungal infections. Previous studies by the group have shown that clioquinol is an important therapeutic alternative in the treatment of dermatophytosis. The object was to conduct studies of antidermatophytic activity and the irritant potential from the double and triple combinations of clioquinol, terbinafine and ciclopirox in ex vivo and in vivo alternative models. To evaluate the irritant potential of antifungal combinations, the alternative HET-CAM method (chicken egg test chorioallantoic membrane) was used. Ex vivo models were used to assess the effectiveness of antifungal combinations, using pig hooves and veterinary fur. Any possible tissue damage was to assess through in histopathology of swine ears. HET-CAM results showed that all combinations can be classified as non-irritating, corroborated by the results of the histopathological evaluation of the pig's ear skin. Only the double combinations managed to remove 100% of the colony-forming units (CFU) formed on the pig's hooves. The clioquinol + terbinafine combination and the triple combination were more effective than clioquinol + ciclopirox in eradicating the preformed biofilm in fur of veterinary origin. These results show the potential of formulations of clioquinol in combination with antifungals for use in humans and in the veterinary field to combat dermatophytosis, as an important alternative therapy, for use in the near future.

Development of an Animal Model of Onychomycosis in Guinea Pigs

Onychomycosis is a common and intractable superficial mycosis that occurs worldwide. Treatment with both oral and topical drugs is recommended, but the objective evaluation procedure to determine the efficacy of and the appropriate delivery system for the drugs remains controversial. This may be attributed to the lack of a reliable animal model that not only mirrors the pathophysiology of human onychomycosis but is also feasible. Therefore, we attempted to establish an animal model of onychomycosis using immunosuppressed guinea pigs and elucidate the pathophysiology of human onychomycosis. In the present study, we applied Trichophyton mentagrophytes TIMM2789 to the hind limb nails of corticosteroid-treated guinea pigs. The nails were examined macroscopically and histopathologically at 0, 14, and 42 days after a 2-week exposure period to the fungus. A large portion of the experimentally infected nails showed discoloration, which is an important clinical sign, and most infections were confirmed histopathologically in the deep layer of the nail plate at all time points. The infection rates at 0, 14, and 42 days after exposure were 39%, 61%, and 78%, respectively. Thus, we established an animal model of onychomycosis with good reproducibility and that might be appropriate for extrapolation to the pathophysiology of the human disease.

Inhibitors of aminoacyl-tRNA synthetases as antimycobacterial compounds: An up-to-date review

Aminoacyl-tRNA synthetases (aaRSs) are crucial for the correct assembly of amino acids to cognate tRNA to maintain the fidelity of proteosynthesis. AaRSs have become a hot target in antimicrobial research. Three aaRS inhibitors are already in clinical practice; antibacterial mupirocin inhibits the synthetic site of isoleucyl-tRNA synthetase, antifungal tavaborole inhibits the editing site of leucyl-tRNA synthetase, and antiprotozoal halofuginone inhibits proline-tRNA synthetase. According to the World Health Organization, tuberculosis globally remains the leading cause of death from a single infectious agent. The rising incidence of multidrug-resistant tuberculosis is alarming and urges the search for new antimycobacterial compounds, preferably with yet unexploited mechanism of action. In this literature review, we have covered the up-to-date state in the field of inhibitors of mycobacterial aaRSs. The most studied aaRS in mycobacteria is LeuRS with at least four structural types of inhibitors, followed by TyrRS and AspRS. Inhibitors of MetRS, LysRS, and PheRS were addressed in a single significant study each. In many cases, the enzyme inhibition activity translated into micromolar or submicromolar inhibition of growth of mycobacteria. The most promising aaRS inhibitor as an antimycobacterial compound is GSK656 (compound 8), the only aaRS inhibitor in clinical trials (Phase IIa) for systemic use against tuberculosis. GSK656 is orally available and shares the oxaborole tRNA-trapping mechanism of action with antifungal tavaborole.

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.

Safety of current therapies for onychomycosis

INTRODUCTION

Onychomycosis is the most common nail disease seen in clinical practice. Treatment options include systemic and topical therapies, as well as devices. Following clinical and mycologic diagnosis, treatment must be individualized, accounting for disease severity, infecting organism(s), comorbidities, patient characteristics and drug/device efficacy. Safety is the most important consideration in choosing the most appropriate therapeutic modality.

AREAS COVERED

This review covers currently available treatments for onychomycosis, with an emphasis on safety and tolerability. Medications and devices were analyzed for side effects, drug-drug interactions, and safety during pregnancy and breastfeeding.

EXPERT OPINION

Systemic antifungals offer greater efficacy for onychomycosis treatment but are limited by risks of systemic toxicity and drug-drug interactions. The risk of terbinafine-induced hepatotoxicity is negligible in healthy patients. Systemic therapies, especially azole antifungals, are associated with numerous drug-drug interactions, some of which are life-threatening and fatal. Thus, a detailed medication history is critical before prescribing these medications. Topical antifungals are well tolerated and generally safe, with only potential local side effects. Systemic and topical onychomycosis treatments should not be prescribed during pregnancy and breastfeeding. Laser therapy is likely less effective than systemic and topical therapies, but may be safely used during pregnancy and breastfeeding.

Effect of onychomycosis and treatment on patient-reported quality-of-life outcomes: A systematic review

BACKGROUND

Onychomycosis is the most common nail disorder, often causing physical, emotional, and aesthetic consequences. The effect of both the condition itself and treatment on quality of life has not been well studied.

OBJECTIVE

The objectives of this study were to systematically review the available literature describing the effect of onychomycosis and treatment on quality of life.

METHODS

We performed a search of the onychomycosis literature published before April 13, 2020. Articles were included in the review if primary data were presented, patient-reported outcome measures were used, and onychomycosis was specifically examined.

RESULTS

Thirty studies were included in the final analysis. Poorest quality-of-life scores were associated with women and fingernail involvement. Quality-of-life scores improved from baseline with all treatment types; there were greater improvements reported with oral treatments compared with topical ones.

CONCLUSIONS

This review affirms that onychomycosis significantly influences quality of life, warranting effective treatment. All treatments resulted in quality-of-life improvements; however, studies on oral and topical therapies were of higher quality than those evaluating devices. Increased efforts are needed to understand the effect of the disease and therapy as assessed by validated, nail-specific outcome measures that accurately assess patients' cosmetic, physical, and social difficulties.

The Canadian Dermatology Association's Top Five Choosing Wisely Canada Recommendations

INTRODUCTION

In this article, we present the Canadian Dermatology Association's (CDA) Choosing Wisely Canada (CWC) list of top "Five Things Physicians and Patients Should Question in Dermatology" and the evidence in support of each recommendation.

METHODS

Using a nominal technique, the CDA Working Group and Task Force generated an initial list based on literature review and expert consultation. After several rounds of list refinement via a modified Delphi process, a final list of recommendations was generated. These were approved by the CDA Board of Directors, presented at the CDA 93rd Annual Conference in 2018, and published by CWC in 2019.

RESULTS

The top five recommendations are as follows: (1) Don't routinely prescribe antibiotics for bilateral lower leg redness and swelling; (2) Don't routinely prescribe topical combination corticosteroid/antifungal products; (3) Don't routinely use topical antibiotics on a surgical wound; (4) Don't prescribe systemic antifungals without mycological confirmation of dermatophyte infection; and (5) Don't use oral antibiotics for acne vulgaris for more than 3 months without assessing efficacy.

DISCUSSION

This list of recommendations aims to encourage both physicians and patients to reevaluate ineffective, yet common, practices in treating dermatologic conditions. These recommendations represent actionable changes in practice, and therefore have considerable potential to enhance value-based care in dermatology.

CONCLUSIONS

This list was developed to identify tangible changes in practice within dermatology that may reduce inefficiencies, prevent potential patient harm, and improve care. Future advocacy work may include updates, feedback obtainment, and patient care handouts, to continue to promote value-based healthcare and best practices.

In vitro antifungal susceptibility testing of fungi in patients with onychomycosis

Onychomycosis is the most common nail disorder. To examine in vitro antifungal susceptibility of fungi among onychomycosis patients. The study included 68 patients with onychomycosis. Nail specimens were cultured on Sabouraud dextrose agar and Dermasel agar base-media. Isolated fungi were subjected to antifungal susceptibility tests against terbinafine, itraconazole, fluconazole, and griseofulvin. Candida species (Candida spp.) were detected in 32.4% of the cases of candidal onychomycosis (n = 37), 23.5% of the cases of distal and lateral subungual onychomycosis (n = 17), and 21.4% of the cases of total dystrophic onychomycosis (n = 14). Candida spp. were sensitive to fluconazole in 73.5%, itraconazole in 58.8%, and terbinafine in 5.9% of the cases. Aspergillus spp. were sensitive to itraconazole in all cases, and terbinafine in 87.5% of cases. Penicillium spp. were sensitive to itraconazole and terbinafine in 88.9% and 77.8% of cases, respectively. Trichophyton spp. were sensitive to terbinafine and resistant to itraconazole. Microsporum spp. were sensitive to itraconazole and resistance to terbinafine. All isolated fungi were resistant to griseofulvin. An increasing proportion of Candida spp. was observed among patients with different clinical varieties of onychomycosis. Candida spp. were highly sensitive to fluconazole and a lesser extent to itraconazole.

Effect of monoterpenes on ex vivo transungual delivery of itraconazole for the management of onychomycosis

BACKGROUND

Onychomycosis, a fungal nail infection, is an important problem as it may cause local pain, paresthesia, difficulties in performing activities of daily life, and impair social interactions. Systemic treatment of onychomycosis presents safety issues due to possible drug-drug interactions and severe side effects. Although topical therapy of onychomycosis is advantageous due to its localized effect, the efficacy of such therapy depends on achieving effective concentrations of antifungal agents at the infection site. An approach to reach to this end would be driving benefit from synergic activity of antifungal agents for example itraconazole and monoterpenes. However, because of low transungual penetration of itraconazole, a molecule with high molecular weight and very low water-solubility, the effect of the latter compounds on itraconazole nail delivery should be investigated, which was the aim of this study.

METHODS

Ex vivo permeation experiments were carried out through soaking the nail clippings of ten healthy volunteers in control and working solutions containing itraconazole (1 mg mL^-1 ) and itraconazole (1 mg mL^-1 ) plus 6% of each monoterpene including camphor, eucalyptol, menthol, and thymol, respectively, for 36 hours. The amount of itraconazole in nail clippings was quantified hereafter using a validated HPLC method.

RESULTS

Statistical analysis showed that itraconazole transungual permeation was not influenced by the studied monoterpenes (P value > .05).

CONCLUSION

These results provided a new perspective for designing topical dosage forms for the treatment of onychomycosis.

Onychomycosis: Diagnosis, Treatment, and Prevention

Toenail disorders account for the majority of foot complaints for which adults seek medical care. Onychomycosis, a fungal nail infection, is the most prevalent. Dermatophytes are responsible for the majority of nail infections and cause varying degrees of nail deformities. While several treatment strategies are available, no one approach (topical, systemic, or mechanical) is highly curative. This article reviews causes, diagnosis, and treatment options for onychomycosis and provides patient education tips to prevent and limit the spread of the disease.