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

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.

Development of microemulgel formulations with varied permeation enhancers for transungual delivery of luliconazole in onychomycosis management

Luliconazole-loaded microemulgels containing different permeation enhancers were formulated for transungual drug delivery for the management of onychomycosis, onychomycosis, which affects nails. The physicochemical properties like droplet size, zeta potential, pH, viscosity, spreadability, extrudability, oil binding capacity, drug content, and microscopic study were evaluated. The Pseudo-ternary phase diagram was constructed for the formulation of microemulsions (MEs) by keeping the Km ratio constant at 3:1 and characterized for clarity, mean droplet size, zeta potential, viscosity, pH, transmittance, refractive index, and stability. The ME mean droplet size and zeta potential were found in the range of 38.78 to 171.4 nm, and 0.00 to - 6.6 mV, respectively. Prepared MEs were converted into microemulgel by adding a 2.5% gelling agent (Carbapol 934) in the external phase, and a drug release study was conducted. Formulation E3 showed better drug release and was chosen as the control. Four different penetration enhancers were added separately within E3 and further evaluated for pH, viscosity, spreadability, extrudability, oil binding capacity, drug content, microscopic study, Compatibility study, XRD, and DSC. A favorable docking score was observed between luliconazole and Lanosterol 14-alpha-demethylase. In-vitro cumulative drug release at the end of 24 h from E3-SS, containing sodium sulfide as a penetration enhancer, was found to be 94.70% and was 2 times more than the control formulation. Ex-vivo transungual permeation studies through cutting nail clippings were found to be in the range of 28.18 - 36.52 µg/mm2. The microemulgels tagged as E3, E3-SS, and E3-SL showed a significant zone of inhibition against Candida albicans and Aspergillus fumigatus as compared to the marketed formulation.

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.

Nanotechnology-based Drug Delivery of Topical Antifungal Agents

Among the various prominent fungal infections, superficial ones are widespread. A large number of antifungal agents and their formulations for topical use are commercially available. They have some pharmacokinetic limitations which cannot be retracted by conventional delivery systems. While nanoformulations composed of lipidic and polymeric nanoparticles have the potential to overcome the limitations of conventional systems. The broad spectrum category of antifungals i.e. azoles (ketoconazole, voriconazole, econazole, miconazole, etc.) nanoparticles have been designed, prepared and their pharmacokinetic and pharmacodynamic profile was established. This review briefly elaborates on the types of nano-based topical drug delivery systems and portrays their advantages for researchers in the related field to benefit the available antifungal therapeutics.

Microfluidic manufacturing of tioconazole loaded keratin nanocarriers: Development and optimization by design of experiments

Fungal infections of the skin, nails, and hair are a common health concern affecting a significant proportion of the population worldwide. The current treatment options include topical and systematic agents which have low permeability and prolonged treatment period, respectively. Consequently, there is a growing need for a permeable, effective, and safe treatment. Keratin nanoparticles are a promising nanoformulation that can improve antifungal agent penetration, providing sustainable targeted drug delivery. In this study, keratin nanoparticles were prepared using a custom-made 3D-printed microfluidic chip and the manufacturing process was optimized using the design of experiments (DoE) approach. The total flow rate (TFR), flow rate ratio (FRR), and keratin concentration were found to be the most influential factors of the size and polydispersity index (PDI) of the nanoparticles. The crosslinking procedure by means of tannic acid as safe and biocompatible compound was also optimized. Keratin nanoparticles loaded with a different amount of tioconazole showed a size lower than 200 nm, a PDI lower than 0.2 and an encapsulation efficiency of 91 ± 1.9 %. Due to their sustained drug release, the formulations showed acceptable in vitro biocompatibility. Furthermore, a significant inhibitory effect compared to the free drug against Microsporum canis.

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.

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.

Poly(pseudo)rotaxanes formed by mixed micelles and α-cyclodextrin enhance terbinafine nail permeation to deeper layers

This work aimed to develop water-based formulations for onychomycosis topical treatment using micelles of small pegylated surfactants associated with α-cyclodextrin (αCD) to deliver terbinafine to the nail. Kolliphor® RH40 (RH40) and Gelucire® 48/16 (GEL) single and mixed micelles (RH40:GEL 1:1) were prepared. αCD was added to the surfactants dispersions to form poly(pseudo)rotaxanes (PPR). Formulations were characterized in terms of drug solubilization (3 to 34-fold increase), particle size (9–11 nm) and Z-potential (+0.3 − +1.96 mV), blood compatibility (non-hemolytic), rheological behavior (solid-like viscoelastic properties after 5–10% αCD addition), drug release and interaction with the nail plate. GEL micelles and surfactant-10% αCD PPRs notably hydrated the nail plate. The high viscosity of PPR led to a slower drug release, except for RH40:GEL +10% αCD that surprisingly released terbinafine faster. The RH40:GEL +10% αCD formulation delivered twice more amount of terbinafine to deeper regions of nail plate compared to other formulations. The results evidenced the potential of PPR formed by small pegylated surfactants as a water-based formulation for nail drug delivery.

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RH40, GEL and their mixed micelles increased 3-fold and 34-fold TB solubility in water and citrate buffer, respectively.

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Addition of αCD (5–10%) led to PPR formation and viscoelastic supramolecular gels without decrease in TB solubilization.

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PPR formulations with 10% αCD enhanced nail plate hydration, increasing its porosity.

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Compared to mixed micelles, PRP showed slower release rate but promoted TB accumulation in deeper regions of hooves.

Iontophoresis application for drug delivery in high resistivity membranes: nails and teeth

Iontophoresis has been vastly explored to improve drug permeation, mainly for transdermal delivery. Despite the skin's electrical resistance and barrier properties, it has a relatively high aqueous content and is permeable to many drugs. In contrast, nails and teeth are accessible structures for target drug delivery but possess low water content compared to the skin and impose significant barriers to drug permeation. Common diseases of these sites, such as nail onychomycosis and endodontic microbial infections that reach inaccessible regions for mechanical removal, often depend on time-consuming and ineffective treatments relying on drug's passive permeation. Iontophoresis application in nail and teeth structures may be a safe and effective way to improve drug transport across the nail and drug distribution through dental structures, making treatments more effective and comfortable for patients. Here, we provide an overview of iontophoresis applications in these "hard tissues," considering specificities such as their high electrical resistivity. Iontophoresis presents a promising option to enhance drug permeation through the nail and dental tissues, and further developments in these areas could lead to widespread clinical use.

Biodegradable Polymers-Based Smart Nanocrystals for Loxoprofen Delivery with Enhanced Solubility: Design, Fabrication and Physical Characterizations

Nanocrystals are carrier-free, submicron-sized, colloidal drug delivery systems with particle sizes in the mean nanometer range. Nanocrystals have high bioavailability and fast absorption because of their high dissolution velocity and enhanced adhesiveness to cell membranes. Loxoprofen, a nonsteroidal anti-inflammatory drug belonging to the Biopharmaceutical Classification System (BCS) II drug class, was selected as the model drug. The aim of this study was to formulate nanocrystals of loxoprofen. A total of 12 formulations (F1 to F12) were prepared. An antisolvent technique was used to determine the effects of various stabilizers and processing conditions on the optimization of formulations. The various stabilizers used were hydroxypropyl methylcellulose (0.5%), polyvinylpyrrolidone (0.5%), and sodium lauryl sulfate (0.1%). The various characterizations conducted for this research included stability studies at 25 °C and 4 °C, scanning electron microscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), zeta potentials, polydispersity indexes, and dissolution studies. F10 was the optimized formulation that showed stability at room temperature, as well as at a refrigerated temperature, for 30 days. A high dissolution rate (100% within the first 10 min) was shown by comparative dissolution studies of nano-suspensions with the micro-suspension and raw loxoprofen. F10 formulation had a non-porous and crystalline morphology on evaluation by TEM and XRPD, respectively, and the average particle size was 300 ± 0.3 nm as confirmed by TEM. DSC recorded a reduction in the melting point (180 °C processed and 200 °C unprocessed melting points). The dissolution rate and solubility of the formulated loxoprofen nanocrystals were significantly enhanced. It can be concluded that selecting suitable stabilizers (i.e., polymers and surfactants) can produce stable nanocrystals, and this can potentially lead to a scaling up of the process for commercialization.

Tailoring the multi-functional properties of phospholipids for simple to complex self-assemblies

The unique interfacial properties, huge diversity, and biocompatible nature of phospholipids make them an attractive pharmaceutical excipient. The amphiphilic nature of these molecules offers them the property to self-assemble into distinct structures. The solubility, chemical and structural properties, surface charge, and critical packing parameters of phospholipids play an essential role during formulation design. This review focuses on the relationship between the structural features of a phospholipid molecule and the formation of different lipid-based nanocarrier drug delivery systems. This provides a rationale and guideline for the selection of appropriate phospholipids while designing a drug delivery system. Finally, we refer to relevant recent case studies covering different types of phospholipid-based systems including simple to complex assemblies. Different carriers in the size range of 50 nm to a few microns can be prepared using phospholipids. The carriers can be delivered through oral, intravenous, nasal, dermal, transmucosal, and subcutaneous routes. A wide range of applicability can be achieved by incorporating various hydrophilic and lipophilic additives in the phospholipid bilayer. Advanced research has led to the discovery of phospholipid complexes and cell membrane mimicking lipids. Overall, phospholipids remain a versatile pharmaceutical excipient for drug delivery. They play multiple roles as solubilizer, emulsifier, surfactant, permeation enhancer, coating agent, release modifier, and liposome former.

Acitretin: Could it be a new therapeutic player in the field of onychomycosis?

BACKGROUND

Onychomycosis represents a therapeutic challenge. The complete cure rate with itraconazole pulse therapy remains unsatisfactory implying the need for an effective therapeutic regimen. Given the successful treatment of recurrent dermatophytosis with isotretinoin and itraconazole, we investigated the therapeutic use of acitretin in onychomycosis.

AIM

To evaluate and compare the efficacy of combined itraconazole and acitretin versus monotherapy with each in onychomycosis.

PATIENTS AND METHODS

The study included 135 adult patients with finger- and/or toe-nail onychomycosis. They were equally subdivided into 3 groups: Itraconazole pulse therapy, acitretin, and combined itraconazole/acitretin therapy. The drugs were administered for 3 months. Evaluation of severity was done by onychomycosis severity index score. Potassium hydroxide microscopy and culture were performed at baseline and at the end of the study.

RESULTS

Mycological and complete cure of onychomycosis was observed in 51.1% and 20% of the itraconazole group, 28.9% and 28.9% of the acitretin group, and 80% and 53.3% of the combined group. There was a statistically-significant difference between groups in favor of the combined itraconazole/acitretin therapy (P ≤ 0.05).

LIMITATIONS

Small sample and short therapy duration.

CONCLUSIONS

Acitretin could be a powerful therapeutic player in the field of onychomycosis, with greater efficacy when combined with itraconazole.

Topical Allopurinol-Loaded Nanostructured Lipid Carriers: A Novel Approach for Wound Healing Management

Nanostructured lipid carriers (NLC) have been widely studied as delivery systems for a variety of routes, including the skin. Their composition results in an imperfect lipid matrix, allowing increased drug encapsulation. Allopurinol (AP), a xanthine oxidase inhibitor, is characterized by low water solubility and high melting point, which has hampered its use through the topical route. In this work, AP was incorporated in a NLC formulation to enhance drug-carrier association and skin delivery as a topical approach to treat wounds. AP-NLC system was characterized in terms of size, charge, rheological behavior, and in vitro skin permeation. The in vitro cytotoxicity was evaluated using HaCaT cells. The wound healing efficacy of the AP-NLC formulation on animal skin lesions was evaluated in male Wistar rats. The AP-NLC presented a mean size of 193 ± 15 nm with a PdI of 0.240 ± 0.02, zeta potential values around −49.6 mV, and an encapsulation efficiency of 52.2%. The AP-NLC formulation presented an adequate profile to be used topically, since epidermal and dermal drug retention were achieved. No reduction in HaCaT cells viability was observed at the tested concentrations (AP < 10 μg/mL). The in vivo application of the AP-NLC formulation resulted in the regeneration of skin lesions when compared with non-treated controls.

Enhanced nail delivery of voriconazole-loaded nanomicelles by thioglycolic acid pretreatment: A study of protein dynamics and disulfide bond rupture

This work aimed to select an effective penetration enhancer (PE) for nail pretreatment, develop voriconazole (VOR)-loaded nanomicelles, and evaluate their ability to deliver VOR to the nail. A complete analysis of nail protein dynamics, bond rupture, and microstructure was performed. Alternative methods as electron paramagnetic resonance (EPR) and the Ellman's reagent (DTNB) assay were also evaluated. Nanomicelles were produced and characterized. The PE hydrated the hooves, following the order: urea ≈ cysteine ≈ glycolic acid < thioglycolic acid (TGA) < NaOH. SEM images and methylene blue assay showed enlarged pores and roughness of porcine hooves after incubation with NaOH and TGA. EPR was demonstrated to be the most sensitive technique. DTNB assay quantified higher thiol groups for samples treated with TGA (p < 0.05). A stratigraphic analysis with Raman spectroscopy demonstrated that hooves treated with TGA presented a higher SH/SS ratio at the edges, affecting protein secondary structure. In vitro permeation studies demonstrated significant VOR permeation (29.44 ± 6.13 µg/cm²), 10-fold higher than previous studies with lipid nanoparticles. After TGA pretreatment, VOR permeation was further enhanced (3-fold). TGA pretreatment followed by VOR-loaded nanomicelles demonstrates a promising approach for onychomycosis treatment. The novel methods for protein analysis were straightforward and helpful.

Development of carvedilol-loaded lipid nanoparticles with compatible lipids and enhanced skin permeation in different skin models

The study aimed to develop lipid nanoparticles using excipients compatible with carvedilol (CARV) for enhanced transdermal drug delivery. Nanostructured lipid carriers (NLC) were successfully obtained and fully characterised. Franz diffusion cells were used for release and in vitro permeation studies in the porcine epidermis (EP) and full-thickness rat skin. NLC4 and NLC5 (0.5 mg/mL of CARV) presented small size (80.58 ± 1.70 and 116.80 ± 12.23 nm, respectively) and entrapment efficiency of 98.14 ± 0.79 and 98.27 ± 0.99%, respectively. CARV-loaded NLC4 and NLC5 controlled drug release. NLC4 allowed CAR permeation through porcine EP in greater amounts than NLC5, i.e. 11.83 ± 4.71 µg/cm² compared to 3.06 ± 0.79 µg/cm². NLC4 increased CARV permeation by 2.5-fold compared to the unloaded drug in rat skin studies (13.73 ± 4.12 versus 5.31 ± 1.56 µg/cm²). NLC4 seems to be a promising carrier for the transdermal delivery of CARV.

Exploiting solid lipid nanoparticles and nanostructured lipid carriers for drug delivery against cutaneous fungal infections

Several types of cutaneous fungal infections can affect the population worldwide, such as dermatophytosis, cutaneous candidiasis, onychomycosis, and sporotrichosis. However, oral treatments have pronounced adverse effects, making the topical route an alternative to avoid this disadvantage. On the other hand, currently available pharmaceutical forms designed for topical application, such as gels and creams, do not demonstrate effective retention of biomolecules in the upper layers of the skin. An interesting approach to optimise biomolecules' activity in the skin is the use of nanosystems for drug delivery, especially solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), which in the past decade has shown advantages like increased adhesiveness, great occlusive properties and higher biomolecule deposition in stratum corneum when designed for topical application. Considering the demand for more effective therapeutic alternatives and the promising characteristics of SLN and NLC for topical application, the present study sought to gather studies that investigated the potential of using SLN and NLC for the treatment of cutaneous fungal infections. Studies demonstrated that these nanosystems showed optimisation, mostly, of the effectiveness of biomolecules besides other biopharmaceutical properties, in addition to offering potential occlusion and hydration of the applied region.

Voriconazole-natural latex dressings for treating infected Candida spp. skin ulcers

Aim: This work aimed to develop a membrane based on voriconazole (VCZ)-loaded natural rubber latex (NRL) for treating infected ulcers with Candida spp. and study their interaction, drug release, antifungal activity against Candida parapsilosis and biological characterization. Materials & methods: VCZ-loaded NRL membrane was produced by casting method. Results: Infrared spectrum showed that the incorporation of VCZ into the NRL membrane maintained its characteristics. Its mechanical properties were considered suitable for dermal application. The VCZ was able to release from NRL membrane, maintaining its antifungal activity against C. parapsilosis, besides did not present hemolytic effects. Conclusion: The VCZ-NRL membrane showed good results in mechanical, antifungal and biological assays, representing an interesting alternative to treatment of infected wound with Candida spp.

Treatment and management strategies of onychomycosis

Onychomycosis is one of the most prevalent and severe nail fungal infections, which is affecting a wide population across the globe. It leads to variations like nail thickening, disintegration and hardening. Oral and topical drug delivery systems are the most desirable in treating onychomycosis, but the efficacy of the results is low, resulting in a relapse rate of 25-30%. Due to systemic toxicity and various other disadvantages associated with oral therapy like gastrointestinal, hepatotoxicity, topical therapy is commonly used. Topical therapy improves patient compliance and reduces the cost of treatment. However, due to poor penetration of topical therapy across the nail plate, research is focused on different chemical, mechanical and physical methods to improve drug delivery. Penetration enhancers like Thioglycolic acid, Hydroxypropyl-β-cyclodextrin (HP-β-CD), Sodium lauryl sulfate (SLS), carbocysteine, N-acetylcysteine etc. have shown results enhancing the drug penetration across the nail plate. Results with physical techniques such as iontophoresis, laser and Photodynamic therapy are quite promising, but the long-term suitability of these devices is in need to be determined. In this article, a brief analysis of the treatment procedures, factors affecting drug permeation across nail plate, chemical, mechanical and physical devices used to increase the drug delivery through nails for the onychomycosis management has been achieved.

SLN and NLC for topical, dermal, and transdermal drug delivery

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

Lipid Nanocarriers for Enhanced Delivery of Temozolomide to the Brain

Brain disorders, a diverse range of conditions comprising of neurological and psychiatric conditions, are the leading cause of disability, severely affect the quality of life, and in many cases lead to mortality. The prime challenge in treatment of brain disorders is to deliver therapeutics by overcoming the blood-brain barrier (BBB), a unique anatomical and physiological barrier which restricts the passage of a number of molecules, proteins, and cells from the bloodstream. Lipid nanoparticles have emerged as promising drug delivery systems primarily because of biodegradability, low toxicity potential, and the ability to cross physiological barriers especially the BBB even without surface modifications.In this chapter we discuss the preparation and characterization of nanostructured lipid carriers of temozolomide, a chemotherapeutic drug. Evaluation of pharmacokinetics and biodistribution of the nanocarrier system in rats revealed improved delivery of the chemotherapeutic agent to the brain with the potential of lesser side effects.

Preparation and in vivo evaluation of a highly skin- and nail-permeable efinaconazole topical formulation for enhanced treatment of onychomycosis

Onychomycosis is a progressive fungal infection of the nails that involves the deeper nail layer and nail bed. It is important to maintain sufficient drug concentration in the diseased tissues after topical application. In this study, a stable topical delivery system for efinaconazole (EFN) was designed to enhance absorption potential through the skin and nail plate by incorporating ethanol, diethylene glycol monoethyl ether (Transcutol P) and isopropyl myristate, and cyclomethicone into the topical solution as a delivery vehicle, permeation enhancers, and a wetting agent, respectively. In addition, the stability of EFN in the formulation was significantly improved by adding butylated hydroxytoluene, diethylenetriamine pentaacetic acid, and citric acid as an antioxidant, chelating agent, and pH-adjusting agent, respectively, without discoloration. The optimum EFN formulation (EFN-K) showed 1.46-fold greater human skin permeation than that of the reference control (commercial 10% EFN topical solution). Furthermore, after a 24-hour incubation, the amount of infiltrated EFN from EFN-K in the human nail plate was 4.11-fold greater than that of the reference control, resulting in an 89.7% increase in nail flux at 7 days after treatment. EFN-K significantly accelerated structural recovery of the keratin layer in a Trichophyton mentagrophytes-infected guinea pig onychomycosis model, decreasing the mean viable fungal cell count by 54.3% compared to the vehicle-treated group after once-daily treatment for 4 weeks. Thus, the accelerated skin and nail penetration effect of EFN-K is expected to achieve good patient compliance, and improve the complete cure rate of onychomycosis.

A comparative study: the prospective influence of nanovectors in leveraging the chemopreventive potential of COX-2 inhibitors against skin cancer

Introduction

This study was conducted to elucidate the chemopreventive potential, cytotoxic, and suppression of cellular metastatic activity of etodolac (ETD)-loaded nanocarriers.

Methods

To esteem the effect of charge and composition of the nanovectors on their performance, four types of vectors namely, negative lipid nanovesicles; phosalosomes (N-Phsoms), positive phosalosomes (P-Phsoms), nanostructured lipid carriers (NLCs) and polymeric alginate polymer (AlgNPs) were prepared and compared. ETD was used as a model cyclo-oxygenase-2 (COX-2) inhibitor to evaluate the potency of these nanovectors to increase ETD permeation and retention through human skin and cytotoxicity against squamous cell carcinoma cell line (SCC). Moreover, the chemopreventive activity of ETD nanovector on mice skin cancer model was evaluated.

Results

Among the utilized nanovectors, ETD-loaded N-Phsoms depicted spherical vesicles with the smallest particle size (202.96±2.37 nm) and a high zeta potential of −24.8±4.16 mV. N-Phsoms exhibited 1.5, and 3.6 folds increase in the ETD amount deposited in stratum corneum, epidermis and dermis. Moreover, cytotoxicity studies revealed a significant cytotoxic potential of such nanovector with IC₅₀=181.76 compared to free ETD (IC₅₀=982.75), correlated to enhanced cellular internalization. Its efficacy extended to a reduction in the relative tumor weight with 1.70 and 1.51-fold compared to positive control and free ETD, that manifested by a 1.72-fold reduction in both COX-2 and proliferating cell nuclear antigen mRNA (PCNA-mRNA) levels and 2.63-fold elevation in caspase-3 level in skin tumors relative to the positive control group with no hepato-and nephrotoxicity.

Conclusion

Encapsulation of ETD in nanovector enhances its in-vitro and in-vivo anti-tumor activity and opens the door for encapsulation of more relevant drugs.

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.

Green Nanotechnology-Driven Drug Delivery Assemblies

Green nanotechnology incorporates the principles of green chemistry and green engineering to fabricate innocuous and eco-friendly nanoassemblies to combat the problems affecting the human health or environment. Subsequently, amalgamation of green nanotechnology with drug delivery area has actually commenced a new realm of "green nanomedicine". The burgeoning demand for green nanotechnology-driven drug delivery systems has led to the development of different types of delivery devices, like inorganic (metallic) nanoparticles, quantum dots, organic polymeric nanoparticles, mesoporous silica nanoparticles, dendrimers, nanostructured lipid carriers, solid lipid nanoparticles, etc. The present article deals with a brief account of delivery devices produced from green methods and describes site-specific drug delivery systems (including their pros and cons) and their relevance in the field of green nanomedicine.

Recent Patents on Permeation Enhancers for Drug Delivery Through Nails

The human nail is a unique barrier with a keratinized constitution that favors protection and fine touch. However, many disorders can affect the nail, among them, are the onychomycosis and psoriasis. Systemic oral therapy has been applied to treat these diseases, even presenting disadvantages, including side effects, drug interactions, contraindications, toxicity, high cost and low patient compliance. A great option to succeed in dealing with the problems associated with oral therapy is the topical administration of drugs. However, nail composition, low diffusion through ungual route and reduced tissue bioavailability for topical treatments are limiting factors. These drawbacks can be overcome by promoting penetration through the nails by employing penetration enhancers. The review focuses on patents that highlight permeation enhancers applied to nail drug delivery for the treatment of onychomycosis and psoriasis. Literature and patent searches were conduced regarding the topic of interest. The substantial literature and patent search revealed that permeation enhancers, especially chemicals, are great strategies for promoting the ungual delivery of drugs. Nail topical therapy containing permeation enhancers is an attractive option for delivering localized treatments.

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.