In-situ gels and nail lacquers as potential delivery systems for treatment of onychomycosis. A comparative study

Development by design of experiment and validation of a HPLC-UV method for simultaneous quantification of 1-nitro-2-phenylethane and methyleugenol: Application to nail permeation/retention studies

Aniba canelilla (Kunth) Mez is an aromatic tree from Amazon region whose essential oil presents 1-nitro-2-phenylethane (NP) and methyleugenol (ME) as major compounds. Several properties are attributed to Aniba canelilla essential oil (ACEO), such as antifungal. Onychomycoses are fungal nail infections that require novel therapeutic alternatives, especially topical ones. However, to ensure the success of topical therapy, the active compound should be able to penetrate/permeate the nail plate, which is challenging due to the highly keratinized composition of this structure. Thus, the aims of this article were to develop, validate and apply a high-performance liquid chromatography method (HPLC-UV) to quantify NP and ME in porcine hoof extract (PHE) and receptor fluid (RF) during in vitro permeation/retention studies in nail model, for which porcine hoof membranes were used. For method development, two Designs of Experiment (DoE) were adopted: 23 Full Factorial and Box-Behnken. Retention times of 5.65 and 7.49 min were achieved for NP and ME, respectively. The method was full validated for NP and ME quantification in receptor fluid, in accordance with the recommended parameters by ICH Q2(R1) Guideline. In addition, the method was full validated for NP and ME quantification in porcine hoof extract, considering the parameters and criteria of ICH M10 Guideline. In vitro permeation/retention studies were carried out in nail model, and promising results were obtained. NP reached the receptor fluid in the order of 441.1 ± 92.1 µg/cm2 at 72 h. The amount of NP and ME retained into porcine hoof membrane was 1272.6 ± 225.7 µg/cm2 and 84.7 ± 20.4 µg/cm2, respectively, at 72 h. Our findings open perspective to develop topical formulations containing ACEO as active compound aiming the management of onychomycosis.

Novel Discoveries and Clinical Advancements for Treating Onychomycosis: A Mechanistic Insight

Onychomycosis continues to be the most challenging disease condition for pharmaceutical scientists to develop an effective drug delivery system. Treatment challenges lie in incomplete cure and high relapse rate. Present compilation provides cumulative information on pathophysiology, diagnostic techniques, and conventional treatment strategies to manage onychomycosis. Novel technologies developed for successful delivery of antifungal molecules are also discussed in brief. Multidirectional information offered by this article also unlocks the panoramic view of leading patented technologies and clinical trials. The obtained clinical landscape recommends the use of advanced technology driven approaches, as a promising way-out for treatment of onychomycosis. Collectively, present review warrants the application of novel technologies for the successful management of onychomycosis. This review will assist readers to envision a better understanding about the technologies available for combating onychomycosis. We also trust that these contributions address and certainly will encourage the design and development of nanocarriers-based delivery vehicles for effective management of onychomycosis.

Topical delivery of extracted curcumin as curcumin loaded spanlastics anti-aging gel: Optimization using experimental design and ex-vivo evaluation

Objective

This study aimed to extract and separate the organic coloring agent known as Curcumin from the rhizomes of Curcuma longa, and then to create Spanlastics that were loaded with curcumin using the ethanol injection technique. The optimized Spanlastic dispersions were then incorporated into a gel preparation for topical anti-aging use. The Spanlastic dispersions were analyzed for particle size, zeta potential, drug loading efficiency, and in vitro release profile. Furthermore, the rheological properties of the gel preparation were assessed, and a skin penetration study was conducted using confocal microscopy.

Methods

Twelve different Curcumin-loaded Spanlastic dispersions using the ethanol injection method with Span® 60 as a surfactant and Tween® 80 as an edge activator in varying ratios. The dispersions were then subjected to various tests, such as particle size analysis, zeta potential measurement, drug entrapment efficiency assessment, and in vitro release profiling. The optimized formula was selected using Design-Expert® software version 13, then used to create a gel preparation, which utilized 2% HPMC E50 as a gelling polymer. The gel was evaluated for its rheological properties and analyzed using confocal microscopy. Additionally, Raman analysis was performed to ensure that the polymers used in the gel were compatible with the drug substance.

Results

F5 formula, (that contains 10 mg Curcumin, and mixture 5 of span-tween mixtures that consist of 120 mg Span® 60 with 80 mg Tween® 80) was selected as the optimized formula with a desirability produced by Design Expert® software equal to 0.761, based on its particle size (212.8 ± 4.76), zeta potential (-29.4 ± 2.11), drug loading efficiency (99.788 ± 1.34), and in vitro release profile evaluations at Q 6hr equal to almost 100 %. Statistical significance (P < 0.05) was obtained using one-way ANOVA. Then F5 was used to formulate HPMC E50 gel-based preparations. The gel formula that was created and analyzed using Raman spectroscopy demonstrated no signs of incompatibility between the Curcumin and the polymers that were utilized.The confocal spectroscopy found that the anti-aging gel preparation showed promising results in terms of skin penetration. Also, images revealed that the gel could penetrate the layers of the skin (reached a depth of about 112.5 μm), where it could potentially target and reduce the appearance of fine lines and wrinkles. The gel also appeared to be well-tolerated by the skin, with no signs of irritation or inflammation observed in the images.

Conclusion

The obtained results successfully confirmed the potential of the promising (F5) formula to produce sustained release action and its ability to be incorporated into 2% HPMC E50 anti-aging gel. The confocal microscopy study suggested that the anti-aging gel had the potential to be an effective and safe topical treatment for aging skin.

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.

Design, Development, and Evaluation of Constant Voltage Iontophoresis for the Transungual Delivery of Efinaconazole

The efficacy of topical antifungal therapy in onychomycosis has been hindered by the failure of the antimycotic to permeate the nail plate. This research aims to design and develop a transungual system for the effective delivery of efinaconazole utilizing constant voltage iontophoresis. Seven prototype drug-loaded hydrogel formulations (E1-E7) were prepared to assess the influence of solvent (ethanol) and cosolvent (Labrasol^®) on transungual delivery. Optimization was performed to evaluate the effect of three independent variables; voltage, solvent-to-cosolvent ratio, and penetration enhancer (PEG 400) concentration on critical quality attributes (CQAs), such as drug permeation and loading into the nail. The selected hydrogel product was characterized for pharmaceutical properties, efinaconazole release from the nail, and antifungal activity. Preliminary data indicates ethanol, Labrasol^®, and voltage influence the transungual delivery of efinaconazole. Optimization design indicates a significant impact by applied voltage (p-0.0001) and enhancer concentration (p-0.0004) on the CQAs. Excellent correlation between selected independent variables and CQAs was confirmed by the high desirability value (0.9427). A significant (p < 0.0001) enhancement in the permeation (~78.59 µg/cm²) and drug loading (3.24 µg/mg) was noticed in the optimized transungual delivery with 10.5 V. FTIR spectral data indicates no interaction between the drug and excipients, while the DSC thermograms confirmed the amorphous state of the drug in the formulation. Iontophoresis produces a drug depot in the nail that releases above the minimum inhibitory concentration level for an extended period, potentially reducing the need for frequent topical treatment. Antifungal studies further substantiate the release data and have shown remarkable inhibition of Trichophyton mentagrophyte. Overall, the promising results obtained here demonstrate the prospective of this non-invasive method for the effective transungual delivery of efinaconazole, which could improve the treatment of onychomycosis.

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

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

Itraconazole and Difluorinated-Curcumin Containing Chitosan Nanoparticle Loaded Hydrogel for Amelioration of Onychomycosis

Onychomycosis is a nail infection caused by a fungus, Trichophyton mentagrophytes, that is responsible for major nail infections. The best method suited for treating such infections generally includes a topical remedy. However, conventional oral or topical formulations are associated with various limitations. Therefore, a more efficient and compatible formulation is developed in this study. The primary objective of the current study is to formulate and evaluate chitosan nanoparticle-based hydrogel for ameliorating onychomycosis. The sole purpose of this research was to increase the permeation of the lipophilic drug itraconazole and difluorinated curcumin, and its synergistic antifungal activity was also evaluated for the first time. Both in vitro and ex vivo drug release evaluations confirmed the sustained release of both drugs from the hydrogel, which is a prerequisite for treating onychomycosis. The results overall highlighted the promising activity of a synergistic approach that could be implemented for the treatment of onychomycosis. The hydrogel-based formulation serves as an effective method of delivery of drugs across the layers of the skin, resulting from its hydrating characteristics.

Formulation-by-Design of Efinaconazole Spanlastic Nanovesicles for Transungual Delivery Using Statistical Risk Management and Multivariate Analytical Techniques

As regulatory and technical landscapes for pharmaceutical formulation development are rapidly evolving, a risk-management approach using multivariate analysis is highly essential for designing a product with requisite critical quality attributes (CQA). Efinaconazole, a newly approved poorly water-soluble antifungal triazole drug has poor permeability. Spanlastics, new-generation surfactant nanovesicles, being fluidic, help improve the permeability of drugs. Therefore, we optimized efinaconazole spanlastics using the concepts of Formulation-by-Design (FbD) and explored the feasibility of transungual delivery for the management of onychomycosis. Using the Ishikawa fishbone diagram, the risk factors that may have an impact on the CQA of efinaconazole spanlastic vesicles were identified. Application of the Plackett–Burman experimental design facilitated the screening of eight different formulation and process parameters influencing particle size, transmittance, relative deformability, zeta potential, entrapment efficiency, and dissolution efficiency. With the help of Pareto charts, the three most significant factors were identified, viz., vesicle builder (Span), edge activator (Tween), and mixing time. The levels of these three critical variables were optimized by FbD to reduce the particle size and maximize the transparency, relative deformability, encapsulation efficiency, and dissolution efficiency of efinaconazole spanlastic nanovesicles. Bayesian and Lenth’s analysis and mathematical modeling of the experimental data helped to quantify the critical formulation attributes required for getting the formulation with optimum quality features. The optimized efinaconazole-loaded spanlastic vesicles had a particle size of 197 nm, transparency of 91%, relative deformability of 12.5 min, and dissolution efficiency of 81.23%. The spanlastic formulation was incorporated into a gel and explored ex vivo for transungual delivery. This explorative study provides an example of the application of principles of risk management, statistical multivariate analysis, and the FbD approach in developing efinaconazole spanlastic nanovesicles.

Trends in the epidemiology of dermatophytosis in the Middle East and North Africa region

Dermatophytosis corresponds to a broad series of infections, mostly superficial, caused by a group of keratinophilic and keratinolytic filamentous fungi called dermatophytes. These mycoses are currently considered to be a major public health concern worldwide, particularly in developing countries such as those in the Middle East and North Africa (MENA) region. Here we compiled and discussed existing epidemiologic data on these infections in the MENA region. Most of the available studies were based on conventional diagnostic strategies and were published before the last taxonomic revision of dermatophytes. This has led to misidentifications, which might have resulted in the underestimation of the real burden of these infections in the MENA countries. Our analysis of the available literature highlights an urgent need for further studies based on reliable diagnostic tools and standard susceptibility testing methods for dermatophytosis, which represents a major challenge for these countries. This is crucial for guiding appropriate interventions and activating antifungal stewardship programs in the future.

Mechanistic Insights of Formulation Approaches for the Treatment of Nail Infection: Conventional and Novel Drug Delivery Approaches

Onychomycosis is a chronic disorder that is difficult to manage and hard to eradicate with perilous trends to relapse. Due to increased prevalence of HIV, use of immunosuppressant drugs and lifestyle-related factors, population affected with fungal infection of nail (Onychomycosis) happens to increase extensively in last two decades. Modalities available for the treatment of onychomycosis include systemically administered antifungals, mechanical procedures, and topical drug therapy. But the efficacy of the most of approaches to deliver drug at targeted site, i.e., deep-seated infected nail bed is limited due to compact and highly keratinized nail structure. A series of advanced formulation approaches, such as transfersomes, liposomes, nano/micro emulsion, nail lacquers etc., have been attempted to improve the drug penetration into nail plate more efficiently. The manuscript reviews these formulation approaches with their possible mechanisms by which they improve the drug penetration.Comparative analysis of available treatment modalities for onychomycosis has been provided with pros and cons of each alternatives. Additionally, ongoing research about the application of biological materials such as modified cationic antimicrobial peptides (AMPs), plant-derived proteins, and synthetic antimicrobial peptidomimetics have also been explored.

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.