An investigation of how fungal infection influences drug penetration through onychomycosis patient's nail plates

Rose bengal-encapsulated chitosan nanoparticles for the photodynamic treatment of Trichophyton species

Rose bengal (RB) solutions coupled with a green laser have proven to be efficient in clearing resilient nail infections caused by Trichophyton rubrum in a human pilot study and in extensive in vitro experiments. Nonetheless, the RB solution can become diluted or dispersed over the tissue and prevented from penetrating the nail plate to reach the subungual area where fungal infection proliferates. Nanoparticles carrying RB can mitigate the problem of dilution and are reported to effectively penetrate through the nail. For this reason, we have synthesized RB-encapsulated chitosan nanoparticles with a peak distribution size of ~200 nm and high reactive oxygen species (ROS) production. The RB-encapsulated chitosan nanoparticles aPDT were shown to kill more than 99% of T. rubrum, T. mentagrophytes, and T. interdigitale spores, which are the common clinically relevant pathogens in onychomycosis. These nanoparticles are not cytotoxic against human fibroblasts, which promotes their safe application in clinical translation.

The Plant Defensin Ppdef1 Is a Novel Topical Treatment for Onychomycosis

Onychomycosis, or fungal nail infection, causes not only pain and discomfort but can also have psychological and social consequences for the patient. Treatment of onychomycosis is complicated by the location of the infection under the nail plate, meaning that antifungal molecules must either penetrate the nail or be applied systemically. Currently, available treatments are limited by their poor nail penetration for topical products or their potential toxicity for systemic products. Plant defensins with potent antifungal activity have the potential to be safe and effective treatments for fungal infections in humans. The cystine-stabilized structure of plant defensins makes them stable to the extremes of pH and temperature as well as digestion by proteases. Here, we describe a novel plant defensin, Ppdef1, as a peptide for the treatment of fungal nail infections. Ppdef1 has potent, fungicidal activity against a range of human fungal pathogens, including Candida spp., Cryptococcus spp., dermatophytes, and non-dermatophytic moulds. In particular, Ppdef1 has excellent activity against dermatophytes that infect skin and nails, including the major etiological agent of onychomycosis Trichophyton rubrum. Ppdef1 also penetrates human nails rapidly and efficiently, making it an excellent candidate for a novel topical treatment of onychomycosis.

Treatment of nail clippings with ethyl alcohol improves the efficacy of Raman spectroscopy in the diagnosis of Trichophyton rubrum onychomycosis

The purpose of this work was to enhance the diagnostic accuracy of nail Raman spectroscopy for fungal nail infections, specifically onychomycosis caused by Trichophyton rubrum. The study assessed the different ethyl alcohol retention rates between control and infected nails after soaking nail clippings in ethanolic solutions and drying. Results revealed that ethyl alcohol completely evaporated from infected nail samples, while significant amounts were still present in control samples. Principal component analysis (PCA) was applied to discriminate control from infected nails and showed superior group separation when nails were treated with ethyl alcohol. PCA loadings plot attributed the efficient classification to the ν_s (CCO) Raman vibrational mode of ethyl alcohol. As Raman spectroscopy can detect minute concentration changes of ethyl alcohol in nails and the deterioration caused by onychomycosis accelerates its evaporation, a simple and rapid method for detecting T. rubrum onychomycosis is proposed.

Relevant insights into onychomycosis' pathogenesis related to the effectiveness topical treatment

Onychomycosis (OM) is a fungal infection, responsible for about 50% of nail diseases. OM has been attributed to the ability of fungi to naturally organize themselves into biofilms on nail surfaces. However, little is known about the exact role of the biofilm in the etiopathogenesis of OM, as well as its influence in the permeation of a topical treatment. The objectives of this study were to review the literature for topical OM treatments in clinical trials, assess the efficiency of these treatments, and discuss factors that could affect the success of these treatments. First, a systematic search of articles published in the MEDLINE database (PubMed) between January 2010 and December 2019 was conducted, focusing on drugs under clinical trials for the topical treatment of OM. Of the publications selected, it was clear that none of them had considered the fungi organized in biofilm. Therefore, we reflected on some important variables involved in OM, such as the nail structure and the mechanism of fungal invasion. Some methods, such as histopathologic analysis and spectroscopy techniques, were found to be effective in the detection of nail biofilm, and could be used in future drug permeation studies. This review allowed us to conclude that novel antifungals for the topical treatment of OM must consider the drug to permeate through biofilm. Natural products, such as propolis, seem strong candidates in this respect.

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.

The Penetrance of Topical Nail Therapy: Limitations and Current Enhancements

The chemical composition and thickness of nails are obstacles for treatments of various nail diseases, such as onychomycosis. Topical medications are currently the preferred method of treatment because of reduced adverse systemic effects. However, penetration of the product from the nail plate into the nail bed continues to be an issue because of factors such as distance required to reach the target area, chemical barriers, and drug inactivation upon keratin binding. Beyond developing novel drugs, some studies have investigated mechanical and chemical methods to optimize drug delivery. The issue of nail diseases is still a challenge and requires multifactorial treatments.

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.

Polishing the Therapy of Onychomycosis Induced by Candida spp.: Amphotericin B-Loaded Nail Lacquer

Onychomycosis induced by Candida spp. has several limitations regarding its treatment. Nail lacquers display the potential to overcome these drawbacks by providing therapeutic compliance and increasing local drug bioavailability. Thus, this work aimed to produce a nail lacquer loaded with Amphotericin B (AmB) and evaluate its performance. The AmB-loaded nail lacquer was produced and preliminarily characterized. An AmB quantification method was developed. Stability, drug release, permeability and anti-Candida activity assays were conducted. The analytical method validation met the acceptance criteria. The drug loading efficiency was 100% (0.02 mg/g of total product), whereas the AmB stability was limited to ≅7 days (≅90% remaining). The nail lacquer displayed a drying time of 187 s, non-volatile content of around 20%_w/w, water-resistance of approximately 2%_w/w of weight loss and satisfactory in vitro adhesion. Moreover, the in vitro antifungal activity against different Candida spp. strains was confirmed. The AmB release and the ex vivo permeability studies revealed that AmB leaves the lacquer and permeates the nail matrix in 47.76 ± 0.07% over 24 h. In conclusion, AmB-loaded nail lacquer shows itself as a promising extemporaneous dosage form with remarkable anti-Candida activity related to onychomycosis.

Ex vivo potential of a quinoline-derivative nail lacquer as a new alternative for dermatophytic onychomycosis treatment

Introduction. Onychomycosis infections currently show a significant increase, affecting about 10 % of the world population. Trichophyton rubrum is the main agent responsible for about 80 % of the reported infections. The clinical cure for onychomycosis is extremely difficult and effective new antifungal therapy is needed.Hypothesis/Gap Statement. Ex vivo onychomycosis models using porcine hooves can be an excellent alternative for evaluating the efficacy of new anti-dermatophytic agents in a nail lacquer.Aim. Evaluation of the effectiveness of a nail lacquer containing a quinoline derivative on an ex vivo onychomycosis model using porcine hooves, as well as the proposal of a plausible antifungal mechanism of this derivative against dermatophytic strains.Methodology. The action mechanism of a quinoline derivative was evaluated through the sorbitol protection assay, exogenous ergosterol binding, and the determination of the dose-response curves by time-kill assay. Scanning electron microscopy evaluated the effect of the derivative in the fungal cells. The efficacy of a quinoline-derivative nail lacquer on an ex vivo onychomycosis model using porcine hooves was evaluated as well.Results. The quinoline derivative showed a time-dependent fungicidal effect, demonstrating reduction and damage in the morphology of dermatophytic hyphae. In addition, the ex vivo onychomycosis model was effective in the establishment of infection by T. rubrum.Conclusion. Treatment with the quinoline-derivative lacquer showed a significant inhibitory effect on T. rubrum strain in this infection model. Finally, the compound presents high potential for application in a formulation such as nail lacquer as a possible treatment for dermatophytic onychomycosis.

Investigation of the Dual-Stage Method of Active Er:YLF Laser Drug Delivery Through the Nail and Laser-Induced Transformations of the Drug Extinction Spectrum

BACKGROUND AND OBJECTIVE

A novel dual-stage method for active laser drug delivery (DSLADD) in the treatment of nail diseases is being presented. This method includes sequentially performed microporation of the nail with submillisecond pulses of Er:YLF laser radiation through a layer of an aqueous solution of drug deposited on the nail surface (Stage 1) and exposure this layer to the same laser radiation to deliver drug under the nail plate (Stage 2). The delivery of methylene blue (MB) as one of the possible drugs in the treatment of nail diseases is investigated. The influence of the thickness of the MB layer, as well as the energy and number of applied laser pulses, on the rate of active laser delivery is discussed. To illustrate the possible effect of delivery on the drug delivered, special attention is paid to the deformation of the extinction spectrum of MB solution after laser irradiation.

STUDY DESIGN/MATERIALS AND METHODS

Diode-pumped Er:YLF laser was used for DSLADD. The process of DSLADD under the nail plate was investigated using digital video microscopy. For different values of the thickness of MB solution layer applied to the nail plate and the energy of laser pulses, the number of laser pulses required to create a single through a microchannel in the nail plate and the number of laser pulses required to deliver the solution to the ventral side of the nail plate after its microporation were registered. The mass and the dose of MB solution penetrated under the nail plate, and the rate of MB solution delivery through a single microchannel was determined. Investigation of the influence of Er:YLF laser radiation parameters on the extinction spectrum of the drug was performed using a fiber spectrometer. The extinction spectra of the 0.001% aqueous solution of MB were recorded before and after exposure to a different number of Er:YLF laser pulses with the energy of 1-4 mJ.

RESULTS

It was found that the minimum number of laser pulses required for active Er:YLF laser drug delivery under the nail corresponds to the MB layer thickness of 100 μm and the laser pulse energy of 4 mJ. It is shown that in this case, the rate of active laser delivery of MB solution reaches 0.26 ± 0.03 mg/pulse. The radiation of the Er:YLF laser affects the shape of the extinction spectrum of the aqueous solution of MВ, which is associated with the transition of the dye from the monomeric to dimeric state. Depending on the laser pulse energy, the fraction of a certain conformational state in the aqueous MB solution can decrease or increase, stimulating a possible change in its photodynamic and antiseptic activity.

CONCLUSION

For the first time, a novel DSLADD through the nail has been described and investigated in vitro. It was demonstrated that at Er:YLF laser pulse repetition rate of f = 30 Hz, microporation of the nail plate and drug delivery through a single microchannel will be about 1.5 s. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Iontophoresis to Overcome the Challenge of Nail Permeation: Considerations and Optimizations for Successful Ungual Drug Delivery

Iontophoresis is a widely used drug delivery technique that has been used clinically to improve permeation through the skin for drugs and other actives in topical formulations. It is however not commonly used for the treatment of nail diseases despite its potential to improve transungual nail delivery. Instead, treatments for nail diseases are limited to relatively ineffective topical passive permeation techniques, which often result in relapses of nail diseases due to the thickness and hardness of the nail barrier resulting in lower permeation of the actives. Oral systemic antifungal agents that are also used are often associated with various undesirable side effects resulting in low patient compliance. This review article discusses what is currently known about the field of transungual iontophoresis, providing evidence of its efficacy and practicality in delivering drug to the entire surface of the nail for extended treatment periods. It also includes relevant details about the nail structure, the mechanisms of iontophoresis, and the associated in vitro and in vivo studies which have been used to investigate the optimal characteristics for a transungual iontophoretic drug delivery system. Iontophoresis is undoubtedly a promising option to treat nail diseases, and the use of this technique for clinical use will likely improve patient outcomes.Graphical abstract.

Human Nails Permeation of an Antifungal Candidate Hydroalcoholic Extract from the Plant Sapindus saponaria L. Rich in Saponins

We evaluated a hydroalcoholic extract of Sapindus saponaria L. pericarps (ETHOSS), as a candidate to a topical antifungal medicine for onychomycosis. ETHOSS was produced by extracting the crushed fruits in ethanol. The saponin contents were identified and characterized by electrospray ionization mass spectrometry. We measured the in vitro antifungal activity against three dermatophyte fungi, isolated from onychomycosis: Trichophyton rubrum, T. mentagrophytes, and T. interdigitale, using broth microdilution tests. The minimum fungicide concentration of ETHOSS ranged from 195.31 to 781.25 μg/mL. The cytotoxicity of the crude extract was tested on the HeLa cell line, and its ability to permeate into healthy human nails by photoacoustic spectroscopy and Fourier transformation infrared spectrometer (FTIR) spectroscopy by attenuated total reflection. Besides its strong antifungal activity, ETHOSS showed low cytotoxicity in human cells. It was able to permeate and reach the full thickness of the nail in one hour, without the aid of facilitating vehicles, and remained there for at least 24 h. These results suggest that ETHOSS has great potential for treating onychomycosis.

Once Weekly Application of Urea 40% and Bifonazole 1% Leads to Earlier Nail Removal in Onychomycosis

Introduction

Onychomycosis is a chronic nail fungal infection resulting in nail damage and a decreased quality of life. Chemical avulsion of the nail with urea and bifonazole -removes fungally infected debris, increasing antifungal treatment efficacy and penetration. Previous clinical ob-servations describe patients who applied their urea and -bifonazole ointment less frequently, achieving earlier nail removal. In this study, we analyzed the relationship between duration of urea and bifonazole application and time to nail avulsion.

Methods

χ² tests, multiple regression analysis, and ANOVA were performed to analyze the similarities between treatment regimens (daily, every 3 days, or once a week), association of regimens or patient characteristics to nail removal, and compare time to nail removal between each regimen, respectively.

Results

Daily application of ointment and sealing resulted in an average length of time (±SD) to nail removal of 18.7 days (±6.8 days); once every 3 days resulted in nail removal at 12.7 days (±6.2 days) and once per week at 11 days (±4.46 days) (p < 0.001). Age was the only patient factor that affected duration to nail removal.

Conclusion

Once weekly application of ointment with sealing for a 1-week duration is associated with a decrease in time to complete chemical avulsion of the nail by approximately 1 week.

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.

Comparison of a fractional 2940-nm Er:YAG laser and 5% amorolfine lacquer combination therapy versus a 5% amorolfine lacquer monotherapy for the treatment of onychomycosis: a randomized controlled trial

Onychomycosis is a fungal infection of the nail. The aim of this randomized controlled clinical trial was to compare the efficacy of 2940-nm Er:YAG laser treatment combined with a 5% amorolfine lacquer versus amorolfine monotherapy for treating onychomycosis. In this study, patients with onychomycosis of the great toenail were randomly assigned to a combination therapy group and a monotherapy group. In the combination therapy group, the included toenails were treated with a fractional 2940-nm Er:YAG laser at weeks 1, 2, 3, 4, 8, and 12, combined with a 5% amorolfine lacquer twice a week for 12 weeks, while in the monotherapy group, the included toenails were treated with only a 5% amorolfine lacquer twice a week for 12 weeks. The onychomycosis severity index (OSI) score and the mycological clearance rate (MCR) of the included toenails were assessed at baseline, week 12, and week 24. At weeks 12 and 24, the great toenails with mild and moderate onychomycosis in the combination therapy group showed obvious improvement and a greater decrease in OSI than those in the monotherapy group. At week 24, the toenails with mild and moderate onychomycosis in the combination therapy group also showed a better MCR. For the toenails with severe onychomycosis, little improvement was observed in either group at week 12 or week 24. In conclusion, fractional 2940-nm Er:YAG laser treatment combined with a 5% amorolfine lacquer is more effective than amorolfine monotherapy in short-term improvement of onychomycosis.

Assessment of the nail penetration of antifungal agents, with different physico-chemical properties

Onychomycosis, or fungal nail infection, is a common fungal infection largely caused by dermatophyte fungi, such as Trichophyton rubrum or Trichophyton mentagrophytes, which affects a significant number of people. Treatment is either through oral antifungal medicines, which are efficacious but have significant safety concerns, or with topical antifungal treatments that require long treatment regimens and have only limited efficacy. Thus, an efficacious topical therapy remains an unmet medical need. Among the barriers to topical delivery through the nail are the physico-chemical properties of the antifungal drugs. Here, we explore the ability of a range of antifungal compounds with different hydrophilicities to penetrate the nail. Human nail discs were clamped within static diffusion (Franz) cells and dosed with equimolar concentrations of antifungal drugs. Using LC-MS/MS we quantified the amount of drug that passed through the nail disc and that which remained associated with the nail. Our data identified increased drug flux through the nail for the more hydrophilic compounds (caffeine as a hydrophilic control and fluconazole, with LogP -0.07 and 0.5, respectively), while less hydrophilic efinaconazole, amorolfine and terbinafine (LogP 2.7, 5.6 and 5.9 respectively) had much lower flux through the nail. On the other hand, hydrophilicity alone did not account for the amount of drug associated with/bound to the nail itself. While there are other factors that are likely to combine to dictate nail penetration, this work supports earlier studies that implicate compound hydrophilicity as a critical factor for nail penetration.

Luliconazole-Loaded Thermosensitive Hydrogel as Aqueous based Nail Lacquer for the Treatment of Onychomycosis

Background:

Onychomycosis is a nail fungal infection which accounts for 50% of the nail diseases and is characterized by disfigurement and discoloration of nails. The current therapy includes oral and topical formulations both of which come with their own drawbacks. This has left a room for developing patient- compliant novel strategies which can facilitate drug delivery deeper into the nails effectively.

Objective:

The main objective of the present work was to develop and evaluate in situ gelling thermosensitive hydrogel as an aqueous nail lacquer for the treatment of onychomycosis. The idea was to enhance permeation of Luliconazole into the nail while simultaneously solubilizing it in a hydrophilic formulation.

Methods:

The sample of Luliconazole was authenticated using modern analytical techniques. The hydrogel- nail lacquer was prepared using poloxamer Pluronic F127. The formulation was evaluated in terms of drying time, viscosity, non- volatile content, pH, transition temperature, etc. In vitro study was done to check the drug release while determining release kinetics. In vitro transungual permeation study was done to check drug permeation through porcine hoof membrane. Stability studies were conducted to ensure formulation stability.

Results:

The results confirmed a stable formulation with enhanced permeation through porcine hoof membrane.

Conclusion:

The results support the potential use of in situ gelling thermo-sensitive hydrogels as a novel transungual formulation in the treatment of onychomycosis with a slight improvement in water resistance.

Novel Drug Delivery Strategies for the Treatment of Onychomycosis

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. It was primarily considered a cosmetic problem but has been garnering attention lately due to its persistent nature and difficult treatment with relapses. With prolonged treatment duration and high cost involved in treating onychomycosis, several attempts have been made in overcoming the rigid nail barrier. The conventional treatment of onychomy-cosis involves oral and topical therapy. The oral antifungal agents though quite effective, are hepato-toxic and cause drug-drug interactions. Topical therapy is more patient compliant being devoid of such adverse effects but it suffers from another setback of improper nail penetration. Amorolfine and ciclopirox nail lacquers are popular market products. Since decades, efforts have been made to enhance topical delivery for efficiently treating ony-chomycosis. Mechanical, physical and chemical methods have been em-ployed. Despite all the attempts made, the nail delivery issues are far from be-ing solved. Recently, the focus has shifted to novel drug delivery systems like nanoparticles, microemulsions, polymeric films and nail lacquers for en-hanced drug permeation and localized therapy. The research around the world is exploring their potential as effective treatment options. This review intends to further explore the novel delivery strategies to treat a persistent fungal in-fection like onychomycosis.

Ucuùba (Virola surinamensis) Fat-Based Nanostructured Lipid Carriers for Nail Drug Delivery of Ketoconazole: Development and Optimization Using Box-Behnken Design

Ucuùba fat is fat obtained from a plant found in South America, mainly in Amazonian Brazil. Due to its biocompatibility and bioactivity, Ucuùba fat was used for the production of ketoconazole-loaded nanostructured lipid carriers (NLC) in view of an application for the treatment of onychomycosis and other persistent fungal infections. The development and optimization of Ucuùba fat-based NLC were performed using a Box-Behnken design of experiments. The independent variables were surfactant concentration (% w/v), liquid lipids concentration (% w/v), solid lipids concentration (% w/v), while the outputs of interest were particle size, polydispersity index (PDI) and drug encapsulation efficiency (EE). Ucuùba fat-based NLC were produced and the process was optimized by the development of a predictive mathematical model. Applying the model, two formulations with pre-determined particle size, i.e., 30 and 85 nm, were produced for further evaluation. The optimized formulations were characterized and showed particle size in agreement to the predicted value, i.e., 33.6 nm and 74.6 nm, respectively. The optimized formulations were also characterized using multiple techniques in order to investigate the solid state of drug and excipients (DSC and XRD), particle morphology (TEM), drug release and interactions between the formulation components (FTIR). Furthermore, particle size, surface charge and drug loading efficiency of the formulations were studied during a one-month stability study and did not show evidence of significant modification.

Polyurethanes as New Excipients in Nail Therapeutics

Onychomycosis affects about 15% of the population. This disease causes physical and psychosocial discomfort to infected patients. Topical treatment (creams, solutions, gels, colloidal carriers, and nail lacquers) is usually the most commonly required due to the high toxicity of oral drugs. Currently, the most common topical formulations (creams and lotions) present a low drug delivery to the nail infection. Nail lacquers appear to increase drug delivery and simultaneously improve the effectiveness of treatment with increased patient compliance. These formulations leave a polymer film on the nail plate after solvent evaporation. The duration of the film residence in the nail constitutes an important property of nail lacquer formulation. In this study, a polyurethane polymer was used to delivery antifungals drugs, such as terbinafine hydrochloride (TH) and ciclopirox olamine (CPX) and the influence of its concentration on the properties of nail lacquer formulations was assessed. The nail lacquer containing the lowest polymer concentration (10%) was the most effective regarding the in vitro release, permeation, and antifungal activity. It has also been demonstrated that the application of PU-based nail lacquer improves the nail plate, making it smooth and uniform and reduces the porosity contributing to the greater effectiveness of these vehicles. To conclude, the use of polyurethane in nail formulations is promising for nail therapeutics.

Evaluation of structural damage and pH of nail plates of hands after applying different methods of decorating

BACKGROUND

The purpose of this study was to evaluate the effect of nail polish, gel polish hybrid, gel nail, and acrylic nail powder and the removal of these formulas on the nail plates properties, particularly the influence of different coatings on morphology and pH.

METHODS

The morphology and structure of nail plates were analyzed with use of scanning electron microscopy. The pH values of the nail plates of hands were measured using the system Courage & Khazaka.

RESULTS

The analysis of morphology and structure of the surface of nail plates showed distinct changes caused by decorative coatings. The most common ones include fragility and splitting of the nails. The pH value measured in the whole group ranged from 5.21 to 7.00.

CONCLUSIONS

The methods used to prepare nails for decoration and all methods of removing the applied preparations damage the healthy nail plates. The most common changes are brittleness and nail splitting. The nail polish remover causes less damage than acetone, and the use of a nail drill machine and nail file causes the greatest destruction of nail plates. The biggest effect on the pH change has the gel polish hybrid, gel nail, and acrylic nail powder, causing the pH value of nail plates to rise above 6.0, whereas after the application of the nail polish, the pH of the plates was on average 5.8 which is closest to the normal value, assumed as physiological.

Onychomycosis in children: Safety and efficacy of antifungal agents

Onychomycosis is an uncommon condition in childhood, but prevalence in children is increasing worldwide.The objective was to review the efficacy and safety of systemic and topical antifungal agents to treat onychomycosis in children. Databases (Pubmed, OVID, Scopus, clinicaltrials.gov, Cochrane Library) were searched. Seven studies were selected for inclusion. Only one was a randomized controlled trial. In total, 208 children were administered antifungal agents for the treatment of onychomycosis. Four reports of mild adverse events were documented (1.9% of treated children), one of which discontinued treatment (0.5%). Limitations of this review are the lack of randomized controlled trials available in pediatric onychomycosis. These findings suggest that antifungal therapies used to treat onychomycosis in children are associated with a low incidence of adverse events. Current dosing regimens for antifungal drugs are effective and appear safe to use in children, notwithstanding that the Food and Drug Administration has not approved any of these agents for the treatment of onychomycosis in children. To our knowledge, this review is the most up-to-date, comprehensive summary of pediatric onychomycosis treatment.

Cross-Linked Fluorescent Supramolecular Nanoparticles for Intradermal Controlled Release of Antifungal Drug-A Therapeutic Approach for Onychomycosis

The existing approaches to onychomycosis demonstrate limited success since the commonly used oral administration and topical cream only achieve temporary effective drug concentration at the fungal infection sites. An ideal therapeutic approach for onychomycosis should have (i) the ability to introduce antifungal drugs directly to the infected sites; (ii) finite intradermal sustainable release to maintain effective drug levels over prolonged time; (iii) a reporter system for monitoring maintenance of drug level; and (iv) minimum level of inflammatory responses at or around the fungal infection sites. To meet these expectations, we introduced ketoconazole-encapsulated cross-linked fluorescent supramolecular nanoparticles (KTZ⊂c-FSMNPs) as an intradermal controlled release solution for treating onychomycosis. A two-step synthetic approach was adopted to prepare a variety of KTZ⊂c-FSMNPs. Initial characterization revealed that 4800 nm KTZ⊂c-FSMNPs exhibited high KTZ encapsulation efficiency/capacity, optimal fluorescent property, and sustained KTZ release profile. Subsequently, 4800 nm KTZ⊂c-FSMNPs were chosen for in vivo studies using a mouse model, wherein the KTZ⊂c-FSMNPs were deposited intradermally via tattoo. The results obtained from (i) in vivo fluorescence imaging, (ii) high-performance liquid chromatography quantification of residual KTZ, (iii) matrix-assisted laser desorption/ionization mass spectrometry imaging mapping of KTZ distribution in intradermal regions around the tattoo site, and (iv) histology for assessment of local inflammatory responses and biocompatibility, suggest that 4800 nm KTZ⊂c-FSMNPs can serve as an effective treatment for onychomycosis.

Preparation and Characterization of Caffeine Loaded Liposome and Ethosome Formulations for Transungual Application

Objectives

Nail plates have a structure that prevents transungual delivery of active agents. This situation makes it difficult to treat nail diseases.

Materials and Methods

In this study, CF-loaded liposome and ethosome formulations were prepared for ungual application. Formulations were characterized by size, microscopic observation, pH, and entrapment efficiency measurements. The effects of formulations and experimental conditions on nails were tested with characterization of nails before and after ex vivo permeation experiments.

Results

Microscopic observation confirmed the presence of spherical-structured vesicles. The particle sizes of vesicles were found as 545.3±0.121 nm, 610.2±0.943 nm, 349.5±0.145 nm and 337.9±0.088 nm for liposomes (FI-FII) and ethosomes (FIII- FIV), respectively. The polydispersity index of particles was found under 0.5, and the pH of formulations was around 7. The encapsulation efficiency was found low due to the hydrophilic character of CF. Nail characterization studies showed that the experimental conditions had an effect on the nail plate.

Conclusion

The cumulative amount of drug after ex vivo permeation studies was found higher for ethosomes than for liposomes. The results confirm that liposomal systems could be promising systems for ungual drug delivery.

Microstructural alterations in the onychomycotic and psoriatic nail: Relevance in drug delivery

Despite the important nail alterations caused by onychomycosis and psoriasis few studies have characterized the microstructure of the diseased nail plate and the diffusion and penetration of drugs through this altered structure. This work aimed to characterize the microstructure of the healthy, onychomycotic and psoriatic human nail using Raman spectroscopy, scanning electron microscopy, optical microscope profilometry and mercury intrusion porosimetry followed by analysis of the structure with PoreCor® software. The results showed that onychomycotic nails have higher porosity and lower amounts of disulphide bonds compared to healthy nails. This suggests that the presence and action of fungi on the nail plate makes this structure more permeable to water and drugs. Psoriatic nails had increased porosity compared to healthy nails but lower than fungal infected specimens. In vitro permeation studies showed that diseased nails were more permeable to ciclopirox (onychomycosis) and clobetasol (psoriasis) although drug permeation was highly variable and likely to be influenced by the degree of alteration of the nail structure. On the whole, this work provides new and valuable information about the microstructure and porosity of diseased nails and a plausible explanation of the increased drug permeability observed in this work and elsewhere.

Voriconazole-loaded nanostructured lipid carriers (NLC) for drug delivery in deeper regions of the nail plate

Voriconazole-loaded nanostructured lipid carriers (VOR-NLC) were developed and drug penetration evaluated in porcine hooves in vitro. Synergistic effect of urea (Ur), selected among other known chemical enhancers according to hoof hydration potential, was also evaluated. VOR-NLC presented a high encapsulation efficiency (74.52±2.13%), approximate mean diameter of 230nm and were positively charged (+27.32±2.74mV). Stability studies indicated they were stable under refrigeration (4±2°C) for up to 150days. SEM images revealed hooves treated with VOR-NLC and VOR-NLC-Ur suffered a disturbance on the surface depicting high roughness and porosity. Permeation data showed a substantial VOR amount retained in superficial hooves sections independent of the formulation used (2.42±0.26; 2.52±0.36 and 2.41±0.60μg/cm² for unloaded VOR, VOR-NLC and VOR-NLC-Ur, respectively, p>0.05). Still, successive extractions, revealed the amount of VOR retained in deeper regions was significantly higher when VOR-NLC or VOR-NLC-Ur was used (0.17±0.04, 0.47±0.14 and 0.36±0.07μg/cm² for unloaded VOR, VOR-NLC and VOR-NLC-Ur, respectively, p<0.05). Such results indicate NLC are promising formulations for the management of onychomycosis. Further studies in diseased nail plates are necessary.

UV-curable gels as topical nail medicines:In vivo residence, anti-fungal efficacy and influence of gel components on their properties

UV-curable gels, used as nail cosmetics for their in vivo durability, were reported to be promising as topical nail medicines. Our first aim was thus to investigate whether such durability applies to drug-loaded formulations. This was found to be true. However, ethanol inclusion in the pharmaceutical formulation (to enable drug loading) reduced the in vivo residence. The second aim was therefore to determine any other effects of ethanol, and if ethanol could be avoided by the choice of monomers. Thus, three methacrylate monomers, ethyl methacrylate, isobornyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) were selected, and their influence on the formulation properties were determined. Ethanol and the methacrylate monomer influenced some (but not all) of the formulation properties. The most significant was that HEMA could dissolve drug and enable the preparation of ethanol-free, drug-loaded formulations, which would benefit in vivo residence. The absence of ethanol reduced drug loading, release and ungual flux, but had no negative impact on the in vitro anti-fungal efficacy. Thus, judicious selection of gel components enabled the exclusion of ethanol. The long in vivo residence, little residual monomers, sufficient ungual permeation and in vitro anti-fungal activity of the gels indicates their potential as anti-onychomycotic topical medicines.