Optimized Ciclopirox-Based Eudragit RLPO Nail Lacquer: Effect of Endopeptidase Enzyme as Permeation Enhancer on Transungual Drug Delivery and Efficiency Against Onychomycosis

Mucoadhesive Chitosan Composite Sponge as a Carrier for β-Sitosterol Cubosomes for Thermal Burn Treatment

Our study aimed to explore the potential of using nanostructured lipid carriers (NLCs) to enhance the topical administration of β-sitosterol, a bioactive that is poorly soluble in water. Here, we have taken advantage of the unique characteristics that cubosomes have to provide as a drug delivery system. These characteristics include a large surface area, thermal stability, and the capacity to encapsulate molecules that are hydrophobic, amphiphilic, and hydrophilic. The cubosomal formulation was optimized by building a central composite design. The optimum dispersion exhibited a particle size of 88.3 nm, a zeta potential of -43, a polydispersity index of 0.358, and drug entrapment of 95.6%. It was composed of 15% w/w oleic acid and 5% w/w pluronic F127. The optimized cubosome dispersion was incorporated into a sponge formulation. The optimized cubosome sponge achieved a higher drug release compared with the cubosome dispersion. The SEM micrograph of the selected sponge showed that it has an interwoven irregular fibrous lamellar structure with low density and high porosity. The in-vivo data revealed that topical application of the β-sitosterol cubosomal sponge showed significant higher wound closure percentage relative to the β-sitosterol product (Mebo)®.

Progress of polymer-based strategies in fungal disease management: Designed for different roles

Fungal diseases have posed a great challenge to global health, but have fewer solutions compared to bacterial and viral infections. Development and application of new treatment modalities for fungi are limited by their inherent essential properties as eukaryotes. The microorganism identification and drug sensitivity analyze are limited by their proliferation rates. Moreover, there are currently no vaccines for prevention. Polymer science and related interdisciplinary technologies have revolutionized the field of fungal disease management. To date, numerous advanced polymer-based systems have been developed for management of fungal diseases, including prevention, diagnosis, treatment and monitoring. In this review, we provide an overview of current needs and advances in polymer-based strategies against fungal diseases. We high light various treatment modalities. Delivery systems of antifungal drugs, systems based on polymers' innate antifungal activities, and photodynamic therapies each follow their own mechanisms and unique design clues. We also discuss various prevention strategies including immunization and antifungal medical devices, and further describe point-of-care testing platforms as futuristic diagnostic and monitoring tools. The broad application of polymer-based strategies for both public and personal health management is prospected and integrated systems have become a promising direction. However, there is a gap between experimental studies and clinical translation. In future, well-designed in vivo trials should be conducted to reveal the underlying mechanisms and explore the efficacy as well as biosafety of polymer-based products.

Chitosan Nanoparticles Loaded Poloxamer 407 Gel for Transungual Delivery of Terbinafine HCl

The current study aimed to develop chitosan nanoparticles (CSNP) loaded poloxamer 407 (P407) gel formulation for transungual delivery of terbinafine HCl (TBN). TBN-CSNP were prepared by nanoprecipitation method and optimized by face-centered central composite design (FCCCD). Optimized TBN-CSNP formulation exhibited a spherical shape with hydrodynamic diameter; zeta potential and entrapment efficiency (EE) of 229 ± 5 nm; 37 ± 1.5 mV; and 75 ± 2% respectively. The solid state of TBN and its compatibility with formulation ingredients were confirmed through XRD and FTIR analysis respectively. TBN-CSNP loaded P407 gel exhibited pseudoplastic rheological behavior having a spreadability of 11 ± 2 g·cm/s. The washability study showed that 40 ± 2% of the gel was eroded after washing 12 times. Drug release from TBN-CSNP- and TBN-CSNP-loaded gel was 84 ± 5% and 57 ± 3%, respectively. The cumulative quantity of TBN permeated from TBN-CSNP-loaded P407 gel and TBN-loaded P407 gel was 25 ± 8 and 27 ± 4 µg/cm2, respectively. The nail uptake study showed that 3.6 ± 0.7 and 2.1 ± 0.3 µg of rhodamine was uptaken by the nail following 2 h topical application of TBN-CSNP loaded P407 gel and TBN loaded P407 gel, respectively. Hence, the developed CSNP-based P407 gel formulation can be a potential carrier for transungual delivery of TBN to topically treat onychomycosis.

Antifungal Nail Lacquer for Enhanced Transungual Delivery of Econazole Nitrate

The fungal disease of the nail, onychomycosis, which is also the most prevalent nail disturbance, demands effective topical treatment options considering the possible adverse effects of systemic antifungal therapy. The current work is focused on development of an adhesive and resistant, drug-delivering and permeation-enhancing polymeric film containing econazole nitrate (ECN) for topical antifungal treatment. The development of the lacquer formulation was guided by the Quality by Design approach to achieve the critical quality attributes needed to obtain the product of desired quality. Eudragit RSPO at 10% w/w was found to be the ideal adhesive polymer for the application and an optimal permeation-enhancing lacquer formulation was achieved by the optimization of other formulation excipients, such as plasticizer and the solvent system. Additionally, novel experimental enhancements introduced to the research included refined D₅₀ drying time and drying rate tests for lacquer characterization as well as a multi-mechanism permeation-enhancing pre-treatment. Moreover, a practical implication was provided by a handwashing simulation designed to test the performance of the lacquer during actual use. In vitro drug release testing and ex vivo nail permeation testing demonstrated that the optimized nail lacquer performed better than control lacquer lacking the permeation enhancer by achieving a faster and sustained delivery of ECN. It can be concluded that this is a promising drug delivery system for topical antifungal treatment of onychomycotic nails, and the novel characterization techniques may be adapted for similar formulations in the future.

Oleic acid-reinforced PEGylated polymethacrylate transdermal film with enhanced antidyslipidemic activity and bioavailability of atorvastatin: A mechanistic ex-vivo/in-vivo analysis

To enhance the poor bioavailability and extensive liver metabolism of atorvastatin calcium (ATC), we have developed an oleic acid-reinforced PEGylated polymethacrylate (OLA-PEG-E-RLPO) transdermal film as a convenient and alternative delivery system. The effect of varying levels of Eudragit RLPO, PEG 400, and oleic acid on the target product profile was optimized through Quality by Design (QbD) approach. The ATC-loaded OLA-PEG-E-RLPO transdermal films were evaluated in ex-vivo experiments using full thickness skin, utilizing Franz cell studies, and undergone in-vivo pharmacokinetics/pharmacodynamics (PK/PD) assessment, using poloxamer-induced dyslipidemic Sprague-Dawley rats. At 2 and 12 h, the optimized ATC films with a thickness of 0.79 mm showed permeation of 37.34% and 97.23% into the receptor compartment, respectively. Steady-state flux was 0.172 mg/cm²h, with 7.01 × 10^-4 cm/h permeability coefficient, and 0.713 × 10^-3 cm²/h diffusion coefficient. In-vivo PK results indicated that the absorption profiles (AUC_0-∞) of the optimized film in pre-treated group of animals were 8.6-fold and 2.8-fold greater than controls pre-treated with non-PEGylated non-oleic acid film and orally administered ATC, respectively. PD assessment of the lipid panel indicated that the lipid profile of the optimized film pre-treated group reached normal levels after 12 h, along with the significant enhancement over the non-PEGylated non-oleic acid film and the oral marketed tablet groups. The histopathological findings revealed near-normal hepatocyte structure for the optimized film pre-treated animal group. Our results further indicate that transdermal delivery films based on an optimized ATC-loaded OLA-PEG-E-RLPO were successfully developed and their assessment in both ex-vivo and in-vivo suggests enhanced permeability and improvement in bioavailability and antidyslipidemic activity of ATC. This approach can provide several advantages, especially during chronic administration of ATC, including improvement in patient compliance, therapeutic benefits, bioavailability, and feasibility for commercialization and as a platform for other drug classes.

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.

Onychomycosis: Current Understanding and Strategies for Enhancing Drug Delivery into Human Nail Tissue

BACKGROUND

Onychomycosis is by far the most common finger or toe nail fungal infectious disease caused by dermatophytes, non-dermatophytic molds or yeast. It accounts for 50% of the total nail disorders, and affects patients physically, socially, and psychologically and can seriously influence their quality of life.

OBJECTIVES

Oral antifungals are routinely used to treat the nail fungal disease; however oral therapy is associated with severe side effects and longer treatment times. In recent years, drug delivery directly into the nail or nail bed has gained attention and various topical products have been tested that can cure the disease when applied topically or transungually. Nevertheless, drug penetration into and through the nail is not straightforward and requires chemicals to improve its permeability or by applying physical stress to promote drug penetration into and through the nail. This lucid review presents an overview of various causes of onychomycosis, current therapeutic approaches, and efforts aimed at increasing the permeability of nails through various strategies such as chemical, physical and mechanical methods for permeation enhancement.

CONCLUSION

Various strategies have been proposed for the treatment of onychomycosis, however, much research into a more precise and effective therapy is still required.

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.

Co-delivery of terbinafine hydrochloride and urea with an in situ film-forming system for nail targeting treatment

Onychomycosis is a chronic nail disorder consisting of a fungal infection that causes physical and psychosocial discomfort to patients. However, its treatment remains challenging owing to the barrier of the highly keratinized nail plate and the short time that conventional formulations reside on nails. In this work, we developed an in situ film-forming system(IFFS) based on Eudragit® RLPO to co-deliver terbinafine hydrochloride (TBH) and urea, i.e., TBH-urea-RLPO IFFS, with the aim of overcoming the nail barrier, prolonging the residence time, and efficiently treating onychomycosis. The IFFS formulation formed a thin film with good appearance and adhesion upon application in situ. The physical states of TBH and urea in the film were evaluated with polarization microscopy and powder X-ray diffraction. TBH and urea were both amorphousmiscible components within the RLPO film. TBH release from TBH-urea-RLPO IFFS fitted to the Korsmeyer-Pappas model, and the cumulative release at 72 h was significantly higher than that from commercial preparations (Lamisil Pedisan® once). In vitro permeation of TBH from TBH-urea-RLPO IFFS through bovine hoof membranes was evaluated in comparison with the film containing TBH alone (TBH-RLPO) and commercial preparations. The retention and cumulative permeated amount of TBH were significantly enhanced for the TBH-urea-RLPO IFFS (170.80 ± 44.63 μg/cm²vs 75.49 ± 21.50 μg/cm²vs 60.25 ± 27.38 μg/cm²; 61.81 ± 16.09 μg/cm²vs 21.80 ± 11.56 μg/cm²vs 7.91 ± 1.03 μg/cm², respectively), and the membranes treated with different formulations were observed with SEM and FTIR to identify the denaturing effect of urea on bovine hoof keratin. In vitro antifungal tests against Trichophyton rubrum,Microsporum canis, Fusarium, and Aspergillus fumigatus were cultured on Muller-Hinton agar; the findings indicated that TBH-urea-RLPO IFFS enhanced TBH antifungal activity. Overall, the results support that TBH-urea-RLPO IFFS is an efficient and promising approach for onychomycosis targeting treatment.

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.

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 onychomycosis 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 onychomycosis. Mechanical, physical and chemical methods have been employed. Despite all the attempts made, the nail delivery issues are far from being solved. Recently, the focus has shifted to novel drug delivery systems like nanoparticles, microemulsions, polymeric films and nail lacquers for enhanced 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 infection like onychomycosis.