Localised and sustained intradermal delivery of methotrexate using nanocrystal-loaded microneedle arrays: Potential for enhanced treatment of psoriasis

Validation of UV-Vis spectrophotometric and colorimetric methods to quantify methotrexate in plasma and rat skin tissue: Application to in vitro release, ex vivo and in vivo studies from dissolving microarray patch loaded pH-sensitive nanoparticle

This research transformed MTX into smart nanoparticles that respond to the acidic conditions present in inflammation. These nanoparticles were then incorporated into a patch that dissolves over time, aiding their penetration. A method using UV-Vis spectrophotometry was validated to support the development of this new delivery system. This method was used to measure the quantity of MTX in the prepared patches in various scenarios: in laboratory solutions with pH 7.4 and pH 5.0, in skin tissue, and plasma. This validation was conducted in laboratory studies, tissue samples, and live subjects, adhering to established guidelines. The resulting calibration curve displayed a linear relationship (correlation coefficient 0.999) across these scenarios. The lowest quantity of MTX that could be accurately detected was 0.6 µg/mL in pH 7.4 solutions, 1.46 µg/mL in pH 5.0 solutions, 1.11 µg/mL in skin tissue, and 1.48 µg/mL in plasma. This validated method exhibited precision and accuracy and was not influenced by dilution effects. The method was effectively used to measure MTX levels in the developed patch in controlled lab settings and biological systems (in vitro, ex vivo, and in vivo). This showed consistent drug content in the patches, controlled release patterns over 24 h, and pharmacokinetic profiles spanning 48 h. However, additional analytical approaches were necessary for quantifying MTX in studies focused on the drug's effects on the body's functions.

Novel nano-in-micro fabrication technique of diclofenac nanoparticles loaded microneedle patches for localised and systemic drug delivery

Diclofenac, a nonsteroidal anti-inflammatory drug, is commonly prescribed for managing osteoarthritis, rheumatoid arthritis, and post-surgical pain. However, oral administration of diclofenac often leads to adverse effects. This study introduces an innovative nano-in-micro approach to create diclofenac nanoparticle-loaded microneedle patches aimed at localised, sustained pain relief, circumventing the drawbacks of oral delivery. The nanoparticles were produced via wet-milling, achieving an average size of 200 nm, and then incorporated into microneedle patches. These patches showed improved skin penetration in ex vivo tests using Franz-cell setups compared to traditional diclofenac formulations. In vivo tests on rats revealed that the nanoparticle-loaded microneedle patches allowed for quick drug uptake and prolonged release, maintaining drug levels in tissues for up to 72 h. With a systemic bioavailability of 57 %, these patches prove to be an effective means of transdermal drug delivery. This study highlights the potential of this novel microneedle delivery system in enhancing the treatment of chronic pain with reduced systemic side effects.

Dissolving microarray patches loaded with a rotigotine nanosuspension: A potential alternative to Neupro® patch

Parkinson's disease (PD), affecting about ten million people globally, presents a significant health challenge. Rotigotine (RTG), a dopamine agonist, is currently administered as a transdermal patch (Neupro®) for PD treatment, but the daily application can be burdensome and cause skin irritation. This study introduces a combinatorial approach of dissolving microarray patch (MAP) and nanosuspension (NS) for the transdermal delivery of RTG, offering an alternative to Neupro®. The RTG-NS was formulated using a miniaturized media milling method, resulting in a nano-formulation with a mean particle size of 274.09 ± 7.43 nm, a PDI of 0.17 ± 0.04 and a zeta potential of -15.24 ± 2.86 mV. The in vitro dissolution study revealed an enhanced dissolution rate of the RTG-NS in comparison to the coarse RTG powder, under sink condition. The RTG-NS MAPs, containing a drug layer and a 'drug-free' supporting baseplate, have a drug content of 3.06 ± 0.15 mg/0.5 cm2 and demonstrated greater amount of drug delivered per unit area (∼0.52 mg/0.5 cm2) than Neupro® (∼0.20 mg/1 cm2) in an ex vivo Franz cell study using full-thickness neonatal porcine skin. The in vivo pharmacokinetic studies demonstrated that RTG-NS MAPs, though smaller (2 cm2 for dissolving MAPs and 6 cm2 for Neupro®), delivered drug levels comparable to Neupro®, indicating higher efficiency per unit area. This could potentially avoid unnecessarily high plasma levels after the next dose at 24 h, highlighting the benefits of dissolving MAPs over conventional transdermal patches in PD treatment.

Calcipotriol Nanosuspension-Loaded Trilayer Dissolving Microneedle Patches for the Treatment of Psoriasis: In Vitro Delivery and In Vivo Antipsoriatic Activity Studies

Psoriasis, affecting 2-3% of the global population, is a chronic inflammatory skin condition without a definitive cure. Current treatments focus on managing symptoms. Recognizing the need for innovative drug delivery methods to enhance patient adherence, this study explores a new approach using calcipotriol monohydrate (CPM), a primary topical treatment for psoriasis. Despite its effectiveness, CPM's therapeutic potential is often limited by factors like the greasiness of topical applications, poor skin permeability, low skin retention, and lack of controlled delivery. To overcome these challenges, the study introduces CPM in the form of nanosuspensions (NSs), characterized by an average particle size of 211 ± 2 nm. These CPM NSs are then incorporated into a trilayer dissolving microneedle patch (MAP) made from poly(vinylpyrrolidone) and w poly(vinyl alcohol) as needle arrays and prefrom 3D printed polylactic acid backing layer. This MAP features rapidly dissolving tips and exhibits good mechanical properties and insertion capability with delivery efficiency compared to the conventional Daivonex ointment. The effectiveness of this novel MAP was tested on Sprague-Dawley rats with imiquimod-induced psoriasis, demonstrating efficacy comparable to the marketed ointment. This innovative trilayer dissolving MAP represents a promising new local delivery system for calcipotriol, potentially revolutionizing psoriasis treatment by enhancing drug delivery and patient compliance.

Dissolvable microarray patches of levodopa and carbidopa for Parkinson's disease management

Carbidopa and levodopa remain the established therapeutic standard for managing Parkinson's disease. Nevertheless, their oral administration is hindered by rapid enzymatic degradation and gastrointestinal issues, limiting their efficacy, and necessitating alternative delivery methods. This work presents a novel strategy employing dissolving microarray patches (MAPs) loaded with carbidopa and levodopa, formulated with Tween® 80 to improve their transdermal delivery. The fabricated MAPs demonstrated an acceptable mechanical strength, resisting pressures equivalent to manual human thumb application (32 N) onto the skin. Additionally, these MAPs exhibited an insertion depth of up to 650 µm into excised neonatal porcine skin. Ex vivo dermatokinetic studies could achieve delivery efficiencies of approximately 53.35 % for levodopa and 40.14 % for carbidopa over 24 h, demonstrating their significant potential in drug delivery. Biocompatibility assessments conducted on human dermal fibroblast cells corroborated acceptable cytocompatibility, confirming the suitability of these MAPs for dermal application. In conclusion, dissolving MAPs incorporating carbidopa and levodopa represent a promising alternative for improving the therapeutic management of Parkinson's disease.

Poly(acrylic acid)/Poly(vinyl alcohol) Microarray Patches for Continuous Transdermal Delivery of Levodopa and Carbidopa: In Vitro and In Vivo Studies

Levodopa (LD) has been the most efficacious medication and the gold standard therapy for Parkinson's disease (PD) for decades. However, its long-term administration is usually associated with motor complications, which are believed to be the result of the fluctuating pharmacokinetics of LD following oral administration. Duodopa® is the current option to offer a continuous delivery of LD and its decarboxylase inhibitor carbidopa (CD); however, its administration involves invasive surgical procedures, which could potentially lead to lifelong complications, such as infection. Recently, dissolving microarray patches (MAPs) have come to the fore as an alternative that can bypass the oral administration route in a minimally invasive way. This work explored the potential of using dissolving MAPs to deliver LD and CD across the skin. An acidic polymer poly(acrylic acid) (PAA) was used in the MAP fabrication to prevent the potential oxidation of LD at neutral pH. The drug contents of LD and CD in the formulated dissolving MAPs were 1.82 ± 0.24 and 0.47 ± 0.04 mg/patch, respectively. The in vivo pharmacokinetic study using female Sprague-Dawley® rats (Envigo RMS Holding Corp, Bicester, UK) demonstrated a simultaneous delivery of LD and CD and comparable AUC values between the dissolving MAPs and the oral LD/CD suspension. The relative bioavailability for the dissolving MAPs was calculated to be approximately 37.22%. Accordingly, this work highlights the use of dissolving MAPs as a minimally invasive approach which could potentially bypass the gastrointestinal pathway and deliver both drugs continuously without surgery.

Nanosuspension-Loaded Dissolving Microneedle Patches for Enhanced Transdermal Delivery of a Highly Lipophilic Cannabidiol

Purpose

Transdermal Drug Delivery System (TDDS) offers a promising alternative for delivering poorly soluble drugs, challenged by the stratum corneum's barrier effect, which restricts the pool of drug candidates suitable for TDDS. This study aims to establish a delivery platform specifically for highly lipophilic drugs requiring high doses (log P > 5, dose > 10 mg/kg/d), to improve their intradermal delivery and enhance solubility.

Methods

Cannabidiol (CBD, log P = 5.91) served as the model drug. A CBD nanosuspension (CBD-NS) was prepared using a bottom-up method. The particle size, polydispersity index (PDI), zeta potential, and concentration of the CBD-NS were characterized. Subsequently, CBD-NS was incorporated into dissolving microneedles (DMNs) through a one-step manufacturing process. The intradermal dissolution abilities, physicochemical properties, mechanical strength, insertion depth, and release behavior of the DMNs were evaluated. Sprague-Dawley (SD) rats were utilized to assess the efficacy of the DMN patch in treating knee synovitis and to analyze its skin permeation kinetics and pharmacokinetic performance.

Results

The CBD-NS, stabilized with Tween 80, exhibited a particle size of 166.83 ± 3.33 nm, a PDI of 0.21 ± 0.07, and a concentration of 46.11 ± 0.52 mg/mL. The DMN loaded with CBD-NS demonstrated favorable intradermal dissolution and mechanical properties. It effectively increased the delivery of CBD into the skin, extended the action's duration in vivo, and enhanced bioavailability. CBD-NS DMN exhibited superior therapeutic efficacy and safety in a rat model of knee synovitis, significantly inhibiting TNF-α and IL-1β compared with the methotrexate subcutaneous injection method.

Conclusion

NS technology effectively enhances the solubility of the poorly soluble drug CBD, while DMN facilitates penetration, extends the duration of action in vivo, and improves bioavailability. Furthermore, CBD has shown promising therapeutic outcomes in treating knee synovitis. This innovative drug delivery system is expected to offer a more efficient solution for the administration of highly lipophilic drugs akin to CBD, thereby facilitating high-dose administration.

Minoxidil Nanosuspension-Loaded Dissolved Microneedles for Hair Regrowth

Minoxidil (MIN) is used topically to treat alopecia. However, its low absorption limits its use, warranting a new strategy to enhance its delivery into skin layers. The objective of this study was to evaluate the dermal delivery of MIN by utilizing dissolved microneedles (MNs) loaded with MIN nanosuspension (MIN-NS) for hair regrowth. MIN-NS was prepared by the solvent-antisolvent precipitation technique. The particle size of MIN-NS was 226.7 ± 9.3 nm with a polydispersity index of 0.29 ± 0.17 and a zeta potential of -29.97 ± 1.23 mV. An optimized formulation of MIN-NS was selected, freeze-dried, and loaded into MNs fabricated with sodium carboxymethyl cellulose (Na CMC) polymeric solutions (MIN-NS-loaded MNs). MNs were evaluated for morphology, dissolution rate, skin insertion, drug content, mechanical properties, ex vivo permeation, in vivo, and stability studies. MNs, prepared with 14% Na CMC, were able to withstand a compression force of 32 N for 30 s, penetrate Parafilm M® sheet at a depth of 374-504 µm, and dissolve completely in the skin within 30 min with MIN %recovery of 95.1 ± 6.5%. The release of MIN from MIN-NS-loaded MNs was controlled for 24 h. MIN-NS-loaded MNs were able to maintain their mechanical properties and chemical stability for 4 weeks, when kept at different storage conditions. The in vivo study of the freeze-dried MIN-NS and MIN-NS-loaded MNs proved hair regrowth on rat skin after 11 and 7 days, respectively. These results showed that MIN-NS-loaded MNs could potentially improve the dermal delivery of MIN through the skin to treat alopecia.

Methotrexate-loaded hyaluronan-modified liposomes integrated into dissolving microneedles for the treatment of psoriasis

Methotrexate (MTX) is a first-line drug in treating psoriasis because of its strong anti-proliferation and anti-inflammatory effects. However, systemic administration of MTX will lead to many side effects, such as gastrointestinal irritation, liver and kidney toxicity, etc. Herein, we developed liposome-loaded microneedles (MNs) system to improve transdermal efficiency, which was used to overcome the problems of low transdermal efficiency and poor therapeutic effect of traditional transdermal drug delivery methods. Hyaluronic acid (HA) was modified on the surface of MTX-loaded liposomes. The interaction of HA and CD44 could increase the adhesion of HA-MTX-Lipo to HaCaT cells, thereby promoting the apoptosis or death of HaCaT cells. Results indicated HA-MTX-Lipo MNs could inhibit the development of psoriasis and reduce the degree of skin erythema, scaling, and thickening. The mRNA levels of proinflammatory cytokines such as IL-17A, IL-23, and TNF-α were decreased. The epidermal thickness and proliferative cell-associated antigen Ki67 expression were also reduced. Specifically, the expression of mRNA levels of proinflammatory cytokines was down-regulated. The MNs transdermal delivery of HA-modified-MTX liposomes provided a promising method for treating psoriasis.

Development of pH-Sensitive Nanoparticle Incorporated into Dissolving Microarray Patch for Selective Delivery of Methotrexate

PURPOSE

Rheumatoid arthritis (RA) is a systemic autoimmune disease that attacks human joints. Methotrexate (MTX), as one the most effective medications to treat RA, has limitations when administered either orally or by injection. To overcome this limitation, we formulated MTX through a smart nanoparticle (SNP) combined with dissolving microarray patch (DMAP) to achieve selective-targeted delivery of RA.

METHODS

SNP was made using the combination of polyethylene glycol (PEG) and polycaprolactone (PCL) polymers, while DMAP was made using the combination of hyaluronic acid and polyvinylpyrrolidone K-30. SNP-DMAP was then evaluated for its mechanical and chemical characteristics, ex vivo permeation test, in vivo pharmacokinetic study, hemolysis, and hen's egg test-chorioallantoic membrane (HET-CAM) test.

RESULT

The results showed that the characteristics of the SNP-DMAP-MTX formulas meet the requirements for transdermal delivery, with the particle size of 189.09 ±12.30 nm and absorption efficiency of 65.40 ± 5.0%. The hemolysis and HET-CAM testing indicate that this formula was non-toxic and non-irritating. Ex vivo permeation shows a concentration of 51.50 ± 3.20 µg/mL of SNP-DMAP-MTX in PBS pH 5.0. The pharmacokinetic profile of SNP-DMAP-MTX showed selectivity and sustained release compared with oral and DMAP-MTX with values of t1/2 (4.88 ± 0 h), Tmax (8 ± 0 h), Cmax (0.50 ± 0.04 μg/mL), AUC (3.15 ± 0.54 μg/mL.h), and mean residence time (MRT) (9.13 ± 0 h).

CONCLUSION

The developed SNP-DMAP-MTX has been proven to deliver MTX transdermal and selectively at the RA site, potentially avoiding conventional MTX side effects and enhancing the effectiveness of RA therapy.

Recent progress of polymeric microneedle-assisted long-acting transdermal drug delivery

Microneedle (MN)-assisted drug delivery technology has gained increasing attention over the past two decades. Its advantages of self-management and being minimally invasive could allow this technology to be an alternative to hypodermic needles. MNs can penetrate the stratum corneum and deliver active ingredients to the body through the dermal tissue in a controlled and sustained release. Long-acting polymeric MNs can reduce administration frequency to improve patient compliance and therapeutic outcomes, especially in the management of chronic diseases. In addition, long-acting MNs could avoid gastrointestinal reactions and reduce side effects, which has potential value for clinical application. In this paper, advances in design strategies and applications of long-acting polymeric MNs are reviewed. We also discuss the challenges in scale manufacture and regulations of polymeric MN systems. These two aspects will accelerate the effective clinical translation of MN products.

Nanocrystals and nanosuspensions: an exploration from classic formulations to advanced drug delivery systems

Nanocrystals and nanosuspensions have become realistic approaches to overcome the formulation challenges of poorly water-soluble drugs. They also represent a less-known but versatile platform for multiple therapeutic applications. They can be integrated into a broad spectrum of drug delivery systems including tablets, hydrogels, microneedles, microparticles, or even functionalized liposomes. The recent progresses, challenges, and opportunities in this field are gathered originally together with an informative case study concerning an itraconazole nanosuspension-in-hydrogel formulation. The translational aspects, historical and current clinical perspectives are also critically reviewed here to shed light on the incoming generation of nanocrystal formulations.

Microneedle-assisted percutaneous delivery of methotrexate-loaded nanoparticles enabling sustained anti-inflammatory effects in psoriasis therapy

Methotrexate (MTX) is one of the first-line drugs used for the treatment of moderate to severe psoriasis. However, low bioavailability and systemic side effects of traditional oral and injectable MTX greatly limit its clinical application. Delivering MTX using dissolving microneedles (MNs) into psoriasis-like skin lesion could improve the in situ therapeutic effects with higher bioavailability and less side effects. Here, we propose a novel therapeutic approach for psoriasis involving MN-assisted percutaneous delivery of chitosan-coated hollow mesoporous silica nanoparticles containing MTX (MTX@HMSN/CS). The MTX@HMSN/CS-loaded MNs were strong enough to successfully penetrate the psoriasiform thickened epidermis, allowing MTX@HMSN/CS to be accurately delivered to the site of skin lesion following the rapid dissolution of MNs. MTX was then released continuously from HMSN/CS for at least one week to maintain effective therapeutic drug concentration for skin lesion with long-term anti-proliferative and anti-inflammatory effects. Incubation with MTX@HMSN/CS not only inhibited the proliferation of human immortalized keratinocytes (HaCaT cells), but also significantly reduced the expression of proinflammatory cytokines and chemokines. In addition, MTX@HMSN/CS-loaded MNs showed better efficacy in alleviating psoriasis-like skin inflammation than MTX-loaded MNs at the same dose. Compared to psoriasiform mice treated with 15.8 μg MTX-loaded MNs every day, 47.4 μg MTX@HMSN/CS-loaded MNs reduce the frequency of treatment to once every 3 days and achieve comparable amelioration. Therefore, MTX@HMSN/CS loaded MNs are a promising treatment strategy for psoriasis due to their durability, efficacy, convenience, and safety in relieving psoriasis-like skin inflammation.

Advancements in transdermal drug delivery: A comprehensive review of physical penetration enhancement techniques

Transdermal drug administration has grown in popularity in the pharmaceutical research community due to its potential to improve drug bioavailability, compliance among patients, and therapeutic effectiveness. To overcome the substantial barrier posed by the stratum corneum (SC) and promote drug absorption within the skin, various physical penetration augmentation approaches have been devised. This review article delves into popular physical penetration augmentation techniques, which include sonophoresis, iontophoresis, magnetophoresis, thermophoresis, needle-free injection, and microneedles (MNs) Sonophoresis is a technique that uses low-frequency ultrasonic waves to break the skin's barrier characteristics, therefore improving drug transport and distribution. In contrast, iontophoresis uses an applied electric current to push charged molecules of drugs inside the skin, effectively enhancing medication absorption. Magnetophoresis uses magnetic fields to drive drug carriers into the dermis, a technology that has shown promise in aiding targeted medication delivery. Thermophoresis is the regulated heating of the skin in order to improve drug absorption, particularly with thermally sensitive drug carriers. Needle-free injection technologies, such as jet injectors (JIs) and microprojection arrays, offer another option by producing temporary small pore sizes in the skin, facilitating painless and effective drug delivery. MNs are a painless, minimally invasive method, easy to self-administration, as well as high drug bioavailability. This study focuses on the underlying processes, current breakthroughs, and limitations connected with all of these approaches, with an emphasis on their applicability in diverse therapeutic areas. Finally, a thorough knowledge of these physical enhancement approaches and their incorporation into pharmaceutical research has the potential to revolutionize drug delivery, providing more efficient and secure treatment choices for a wide range of health-related diseases.

Dual engine-driven bionic microneedles for early intervention and prolonged treatment of Alzheimer's disease

The microneedle (MN) delivery system presents an attractive administration route for patients with Alzheimer's disease (AD). However, the passive drug delivery mode and low drug loading of MNs often result in unsatisfactory therapeutic efficiency. To address these dilemmas, we developed dual engine-drive bionic MNs for robust AD treatment. Specifically, free rivastigmine (RVT) and RVT particles were co-loaded within the MNs to construct the valve and chambers of the guava, respectively, which can serve as an active engine to promote drug permeation by generating capillary force. K2CO3 and citric acid were introduced as a pneumatic engine into the MNs to promote the permeation of free RVT into deeper skin layers for early intervention in AD. Further, the RVT particles served as a drug depot to provide continuous drug release for prolonged AD treatment. Compared with free RVT-loaded MNs, the dual engine-driven bionic MNs showed an increase in drug loading, cumulative transdermal permeability, and normalized bioavailability of approximately 40%, 22%, and 49%, respectively. Pharmacodynamic studies further confirmed that the dual engine-driven bionic MNs were most effective in restoring memory and recognition functions in mice with short-term memory dysfunction. Therefore, the dual engine-driven bionic MNs hold great promise for highly efficient AD treatment.

Potential strategy of microneedle-based transdermal drug delivery system for effective management of skin-related immune disorders

Skin-related immune disorders are a category of diseases that lead to the dysregulation of the body's immune response due to imbalanced immune regulation. These disorders exhibit diverse clinical manifestations and complicated pathogenesis. The long-term use of corticosteroids, anti-inflammatory drugs, and immunosuppressants as traditional treatment methods for skin-related immune disorders frequently leads to adverse reactions in patients. In addition, the effect of external preparations is not ideal in some cases due to the compacted barrier function of the stratum corneum (SC). Microneedles (MNs) are novel transdermal drug delivery systems that have theapparent advantages ofpenetrating the skin barrier, such as long-term and controlled drug delivery, less systemic exposure, and painless and minimally invasive targeted delivery. These advantages make it a good candidate formulation for the treatment of skin-related immune disorders and a hotspot for research in this field. This paper updates the classification, preparation, evaluation strategies, materials, and related applications of five types of MNs. Specific information, including the mechanical properties, dimensions, stability, and in vitro and in vivo evaluations of MNs in the treatment of skin-related immune disorders, is also discussed. This review provides an overview of the advances and applications of MNs in the effective treatment of skin-related immune disorders and their emerging trends.

A Bilayer Microarray Patch (MAP) for HIV Pre-Exposure Prophylaxis: The Role of MAP Designs and Formulation Composition in Enhancing Long-Acting Drug Delivery

Microarray patches (MAPs) have shown great potential for efficient and patient-friendly drug delivery through the skin; however, improving their delivery efficiency for long-acting drug release remains a significant challenge. This research provides an overview of novel strategies aimed at enhancing the efficiency of MAP delivery of micronized cabotegravir sodium (CAB Na) for HIV pre-exposure prophylaxis (PrEP). The refinement of microneedle design parameters, including needle length, shape, density, and arrangement, and the formulation properties, such as solubility, viscosity, polymer molecular weight, and stability, are crucial for improving penetration and release profiles. Additionally, a bilayer MAP optimization step was conducted by diluting the CAB Na polymeric mixture to localize the drug into the tips of the needles to enable rapid drug deposition into the skin following MAP application. Six MAP designs were analyzed and investigated with regard to delivery efficiency into the skin in ex vivo and in vivo studies. The improved MAP design and formulations were found to be robust and had more than 30% in vivo delivery efficiency, with plasma levels several-fold above the therapeutic concentration over a month. Repeated weekly dosing demonstrated the robustness of MAPs in delivering a consistent and sustained dose of CAB. In summary, CAB Na MAPs were able to deliver therapeutically relevant levels of drug.

Impact of the crystal size of crystalline active pharmaceutical compounds on loading into microneedles

Microneedle (MN) technology offers a promising platform for the delivery of a wide variety of active pharmaceutical compounds into and/or through the skin. Yet, the low loading capacity of MNs limits their clinical translation. The solid state of loaded compounds, crystallinity versus amorphousness and crystal size of the former, could greatly affect their loading. Here, we investigated the effect of the crystal size of crystalline compounds on their loading into dissolving MNs, prepared using the solvent-casting technique. A model crystalline compound was subjected to crystal size reduction via wet bead milling and loaded into dissolving MNs. A range of crystal sizes, from micro to nano, was obtained via different milling periods. The obtained crystals were characterized for their size, morphology, and sedimentation behavior. Besides, their content, solid state inside the MNs, and impact on the MN mechanical strength were assessed. The crystals exhibited size-dependent sedimentation, which dramatically affected their loading inside the MNs. However, crystal size and sedimentation demonstrated a negligible effect on the mechanical strength and sharpness of the needles, hence no anticipated impact on the MNs' drug delivery efficiency. The elucidation of the correlation between the crystal size and MN loading opens new potentials to address a major drawback in MN technology.

New Insights into Pharmaceutical Nanocrystals for the Improved Topical Delivery of Therapeutics in Various Skin Disorders

Nanotechnology has provided nanostructure-based delivery of drugs, among which nanocrystals have been investigated and explored for feasible topical drug delivery. Nanocrystals are nano-sized colloidal carriers, considered pure solid particles with a maximum drug load and a very small amount of stabilizer. The size or mean diameter of the nanocrystals is less than 1 μm and has a crystalline character. Prominent synthesis methods include the utilization of microfluidic- driven platforms as well as the milling approach, which is both adaptable and adjustable. Nanocrystals have shown a high capacity for loading drugs, utilization of negligible amounts of excipients, greater chemical stability, lower toxic effects, and ease of scale-up, as well as manufacturing. They have gained interest as drug delivery platforms, and the significantly large surface area of the skin makes it a potential approach for topical therapeutic formulations for different skin disorders including fungal and bacterial infections, psoriasis, wound healing, and skin cancers, etc. This article explores the preparation techniques, applications, and recent patents of nanocrystals for treating various skin conditions.

Dissolving microneedle patch-assisted transdermal delivery of methotrexate improve the therapeutic efficacy of rheumatoid arthritis

Methotrexate (MTX) is a first-line treatment for rheumatoid arthritis (RA), but its clinical use is greatly limited by the adverse effects and poor patient compliance caused by traditional oral administration or injection. In recent years, some transdermal drug delivery systems have received considerable attention due to overcoming these shortcomings. In this study, we developed dissolving microneedle patch (DMNP) for transdermal delivery of MTX to treat RA safely and effectively. The morphology, mechanical strength, skin insertion, drug content, in vitro transdermal delivery, and other properties of DMNP were characterized. Meanwhile, the adjuvant-induced arthritis model of rats was established to investigate the therapeutic effect of MTX-loaded DMNP in vivo. The results showed that the microneedles had excellent morphology with neat array and complete needles, good puncture performance and mechanical strength, and rapid intradermal dissolution rate. In vitro transdermal delivery results indicated that microneedles could significantly increase drug transdermal permeation compared with the cream group. The pharmacological study showed that MTX-loaded DMNP significantly alleviated paw swelling, inhibit inflammatory response via downregulating the levels of TNF-α and IL-1β, relieved synovium destruction with less cartilage erosion, and slowed the progression of RA in AIA rats. Besides, DMNP presented better therapeutic performance than cream or intragastric administration at the same dosage of MTX. In conclusion, the MTX-loaded dissolving microneedle patch has advantages of safety, convenience, and high efficacy over conventional administrations, laying a foundation for the transdermal drug delivery system treatment of rheumatoid arthritis.

A Novel Methacryloyl Chitosan Hydrogel Microneedles Patch with Sustainable Drug Release Property for Effective Treatment of Psoriasis

Psoriasis is a chronic and recurrent skin disease that often requires long-term treatment, and topical transdermal drug delivery can reduce systemic side effects. However, it is still a challenge in efficient transdermal drug delivery for psoriasis treatment due to low penetration efficiency of most drugs and the abnormal skin conditions of psoriasis patients. Here, a safe and effective methacryloyl chitosan hydrogel microneedles (CSMA hMNs) patch is developed and served as a sustained drug release platform for the treatment of psoriasis. By systematically optimizing the CSMA preparation, CSMA hMNs with excellent morphological characteristics and strong mechanical properties (0.7 N needle-1 ) are prepared with a concentration of only 3% (w/v) CSMA. As a proof-of-concept, methotrexate (MTX) and nicotinamide (NIC) are loaded into CSMA hMNs patch, which can produce a sustained drug release of 80% within 24 h in vitro. In vivo experiments demonstrated that the CSMA hMNs patch can effectively inhibit the skin thickening and spleen enlargement of psoriatic mice and has a good biosafety profile at sufficient therapeutic doses. This study provides a new idea for the preparation of hMN systems using modified CS or other biocompatible materials and offers an effective therapeutic option for psoriasis treatment.

Simvastatin nanocrystals-based dissolving microneedles for wound healing

Currently, one of the main problems encountered in wound healing therapy is related to inefficient drug delivery. However, dissolving microneedles (DMNs) can be administered percutaneously to effectively deliver a drug to a deep wound area. Simvastatin (SIM) can promote wound healing, albeit its insolubility in water limits its application. Here, we designed a DMNs (SIM-NC@DMNs) drug delivery system loaded with SIM nanocrystals (SIM-NC) and evaluated its efficacy in wound healing. Based on our observations, the dissolution performance of insoluble SIM is significantly improved after the preparation of SIM-NC. For example, the saturation solubility of SIM-NC in deionized water and PBS increased by 150.57 times and 320.14 times, respectively. After the SIM-NC@DMNs are deeply inserted into the wound, the needle portion, which is composed of hyaluronic acid (HA), dissolves rapidly, and the SIM-NC loaded on the needle portion is efficiently released into the deep wound area for optimal therapeutic efficacy. The combination of NC and DMNs makes this system further effective for wound healing. Our cumulative work suggests that the newly developed SIM-NC@DMNs possess great potential in accelerating wound healing. By day 12 after treatment, the residual wound area in the Control group was 21.34 %, while the residual wound area in the SIM-NC@DMNs group was only 2.36 %. This result as well as provides certain evidence of its efficacy for wound healing therapy. The SIM-NC@DMNs drug delivery system may become an efficient treatment modality that promotes wound healing, with a promising potential in the field of wound healing research.

Hydrogel-Based Microneedle as a Drug Delivery System

The skin is considered the largest and most accessible organ in the human body, and allows the use of noninvasive and efficient strategies for drug administration, such as the transdermal drug delivery system (TDDS). TDDSs are systems or patches, with the ability and purpose to deliver effective and therapeutic doses of drugs through the skin. Regarding the specific interaction between hydrogels (HG) and microneedles (MNs), we seek to find out how this combination would be applied in the context of drug delivery, and we detail some possible advantages of the methods used. Depending on the components belonging to the HG matrix, we can obtain some essential characteristics that make the combination of hydrogels-microneedles (HG-MNs) very advantageous, such as the response to external stimuli, among others. Based on multiple characteristics provided by HGMNs that are depicted in this work, it is possible to obtain unique properties that include controlled, sustained, and localized drug release, as well as the possibility of a synergistic association between the components of the formulation and the combination of more than one bioactive component. In conclusion, a system based on HG-MNs can offer many advantages in the biomedical field, bringing to light a new technological and safe system for improving the pharmacokinetics and pharmacodynamics of drugs and new treatment perspectives.

Long-acting microneedle formulations

The minimally-invasive and painless nature of microneedle (MN) application has enabled the technology to obviate many issues with injectable drug delivery. MNs not only administer therapeutics directly into the dermal and ocular space, but they can also control the release profile of the active compound over a desired period. To enable prolonged delivery of payloads, various MN types have been proposed and evaluated, including dissolving MNs, polymeric MNs loaded or coated with nanoparticles, fast-separable MNs hollow MNs, and hydrogel MNs. These intricate yet intelligent delivery platforms provide an attractive approach to decrease side effects and administration frequency, thus offer the potential to increase patient compliance. In this review, MN formulations that are loaded with various therapeutics for long-acting delivery to address the clinical needs of a myriad of diseases are discussed. We also highlight the design aspects, such as polymer selection and MN geometry, in addition to computational and mathematical modeling of MNs that are necessary to help streamline and develop MNs with high translational value and clinical impact. Finally, up-scale manufacturing and regulatory hurdles along with potential avenues that require further research to bring MN technology to the market are carefully considered. It is hoped that this review will provide insight to formulators and clinicians that the judicious selection of materials in tandem with refined design may offer an elegant approach to achieve sustained delivery of payloads through the simple and painless application of a MN patch.

Microneedle array patches for sustained delivery of fluphenazine: A micron scale approach for the management of schizophrenia

Schizophrenia is a severe chronic mental illness characterised by impaired emotional and cognitive functioning. To treat this condition, antipsychotics are available in limited dosage forms, mainly oral and injectable formulations. Although injectable antipsychotics were designed to enhance adherence, they are invasive, painful and require a healthcare professional to be administered. To overcome such administration issues, extensive research has been focused on developing transdermal antipsychotic formulations. In this work, three microneedle (MN) systems were developed to deliver fluphenazine (FLU) systemically. A decanoic prodrug of FLU called fluphenazine decanoate (FLUD) was used in two of the MN formulations due to its high lipophilicity. FLU-D was loaded into dissolving MNs and nanoemulsion (NE)-loaded MNs. The parent drug FLU was loaded into poly(lactic-co-glycolic acid) (PLGA)-tipped MNs. All MN systems were characterised and evaluated in vitro and in vivo. The in vivo evaluation of the three developed MN systems showed their ability to deliver FLU into the systemic circulation, as the Cmax of FLU-D dissolving MNs was 36.11 ± 12.37 ng/ml. However, the Cmax of FLU-D NE loaded dissolving MNs was 12.92 ± 6.3 ng/ml and for FLU-PLGA tipped MNs was 21.57 ± 2.45 ng/ml. Compared to an intramuscular (IM) injection of FLU-D in sesame oil, the relative bioavailabilities were 26.96 %, 21.73 % and 42.45 % for FLU-D dissolving MNs, FLU-D NE dissolving MNs and FLU-PLGA tipped MNs, respectively. FLU plasma levels were maintained above the minimum human therapeutic limits for a week. Consequently, these various MN formulations are considered to be a viable options for the transdermal delivery of fluphenazine and its prodrug. The three MN systems developed offer patients a user-friendly, painless, and convenient long-acting delivery method for FLU. Reducing dosing frequency and using less invasive drug administration methods can enhance adherence and foster positive therapeutic outcomes. This study demonstrates the capability and adaptability of MNs technology to transport hydrophobic molecules from the skin to the systemic circulation.

Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects

INTRODUCTION

The fabrication of well-defined nanocrystals in size and form is the focus of much investigation. In this work, we have critically reviewed several recent instances from the literature that shows how the production procedure affects the physicochemical properties of the nanocrystals.

AREAS COVERED

Scopus, MedLine, PubMed, Web of Science, and Google Scholar were searched for peer-review articles published in the past few years using different key words. Authors chose relevant publications from their files for this review. This review focuses on the range of techniques available for producing nanocrystals. We draw attention to several recent instances demonstrating the impact of various process and formulation variables that affect the nanocrystals' physicochemical properties. Moreover, various developments in the characterization techniques explored for nanocrystals concerning their size, morphology, etc. have been discussed. Last but not least, recent applications, the effect of surface modifications, and the toxicological traits of nanocrystals have also been reviewed.

EXPERT OPINION

The selection of an appropriate production method for the formation of nanocrystals, together with a deep understanding of the relationship between the drug's physicochemical properties, unique features of the various formulation alternatives, and anticipated in-vivo performance, would significantly reduce the risk of failure during human clinical trials that are inadequate.

Exosome-loaded microneedle patches: Promising factor delivery route

During the past decades, the advent of different microneedle patch (MNPs) systems paves the way for the targeted and efficient delivery of several growth factors into the injured sites. MNPs consist of several micro-sized (25-1500 μm) needle rows for painless delivery of incorporated therapeutics and increase of regenerative outcomes. Recent data have indicated the multifunctional potential of varied MNP types for clinical applications. Advances in the application of materials and fabrication processes enable researchers and clinicians to apply several MNP types for different purposes such as inflammatory conditions, ischemic disease, metabolic disorders, vaccination, etc. Exosomes (Exos) are one of the most interesting biological bioshuttles that participate in cell-to-cell paracrine interaction with the transfer of signaling biomolecules. These nano-sized particles, ranging from 50 to 150 nm, can exploit several mechanisms to enter the target cells and deliver their cargo into the cytosol. In recent years, both intact and engineered Exos have been increasingly used to accelerate the healing process and restore the function of injured organs. Considering the numerous benefits provided by MNPs, it is logical to hypothesize that the development of MNPs loaded with Exos provides an efficient therapeutic platform for the alleviation of several pathologies. In this review article, the authors collected recent advances in the application of MNP-loaded Exos for therapeutic purposes.

Development of dissolving microneedles for intradermal delivery of the long-acting antiretroviral drug bictegravir

Oral administration and intramuscular (IM) injection are commonly recommended options for human immunodeficiency virus (HIV) treatment. However, poor patient compliance due to daily oral dosing, pain at injection sites and the demand for trained healthcare staff for injections limit the success of these administration routes, especially in low-resource settings. To overcome these limitations, for the first time, we propose novel bilayer dissolving microneedles (MNs) for the intradermal delivery of long-acting nanosuspensions of the antiretroviral (ARV) drug bictegravir (BIC) for potential HIV treatment and prevention. The BIC nanosuspensions were prepared using a wet media milling technique on a laboratory scale with a particle size of 358.99 ± 18.53 nm. The drug loading of nanosuspension-loaded MNs and BIC powder-loaded MNs were 1.87 mg/0.5 cm² and 2.16 mg/0.5 cm², respectively. Both dissolving MNs exhibited favorable mechanical and insertion ability in the human skin simulant Parafilm® M and excised neonatal porcine skin. Importantly, the pharmacokinetic profiles of Sprague Dawley rats demonstrated that dissolving MNs were able to intradermally deliver 31% of drug loading from nanosuspension-loaded MNs in the form of drug depots. After a single application, both coarse BIC and BIC nanosuspensions achieved sustained release, maintaining plasma concentrations above human therapeutic levels (162 ng/mL) in rats for 4 weeks. These minimally invasive and potentially self-administered MNs could improve patient compliance, providing a promising platform for the delivery of nanoformulated ARVs and resulting in prolonged drug release, particularly for patients in low-resource settings.

Development of probiotic loaded multilayer microcapsules incorporated into dissolving microneedles for potential improvement treatment of vulvovaginal candidiasis: A proof of concept study

Vulvovaginal candidiasis (VVC) is a vaginal infection caused by abnormal growth of Candida sp., especially Candida albicans, in the vaginal mucosa. A shift in vaginal microbiota is prominent in VVC. The presence of Lactobacillus plays a vital role in maintaining vaginal health. However, several studies have reported resistance of Candida sp. against azoles drugs, which is recommended as VVC treatment. The use of L. plantarum as a probiotic would be an alternative to treat VVC. In order to exert their therapeutic activity, the probiotics needed to remain viable. Multilayer double emulsion was formulated to obtain L. plantarum loaded microcapsules (MCs), thus improving its viability. Furthermore, a vaginal drug delivery system using dissolving microneedles (DMNs) for VVC treatment was developed for the first time. These DMNs showed sufficient mechanical and insertion properties, dissolved rapidly upon insertion, facilitating probiotic release. All formulations proved non-irritating, non-toxic, and safe to apply on the vaginal mucosa. Essentially, the DMNs could inhibit the growth of Candida albicans up to 3-fold than hydrogel and patch dosage forms in ex vivo infection model. Therefore, this study successfully developed the formulation of L. plantarum-loaded MCs with multilayer double emulsion and its combination in DMNs for vaginal delivery to treat VVC.

Natural products targeting inflammation-related metabolic disorders: A comprehensive review

Currently, the incidence of metabolic disorders is increasing, setting a challenge to global health. With major advancement in the diagnostic tools and clinical procedures, much has been known in the etiology of metabolic disorders and their corresponding pathophysiologies. In addition, the use of in vitro and in vivo experimental models prior to clinical studies has promoted numerous biomedical breakthroughs, including in the discovery and development of drug candidates to treat metabolic disorders. Indeed, chemicals isolated from natural products have been extensively studied as prospective drug candidates to manage diabetes, obesity, heart-related diseases, and cancer, partly due to their antioxidant and anti-inflammatory properties. Continuous efforts have been made in parallel to improve their bioactivity and bioavailability using selected drug delivery approaches. Here, we provide insights on recent progress in the role of inflammatory-mediated responses on the initiation of metabolic disorders, with particular reference to diabetes mellitus, obesity, heart-related diseases, and cancer. In addition, we discussed the prospective role of natural products in the management of diabetes, obesity, heart-related diseases, and cancers and provide lists of potential biological targets for high throughput screening in drug discovery and development. Lastly, we discussed findings observed in the preclinical and clinical studies prior to identifying suitable approaches on the phytochemical drug delivery systems that are potential to be used in the treatment of metabolic disorders.

Formulation of antiretroviral nanocrystals and development into a microneedle delivery system for potential treatment of HIV-associated neurocognitive disorder (HAND)

HIV/AIDS remains a major global public health issue. While antiretroviral therapy is effective at reducing the viral load in the blood, up to 50% of those with HIV suffer from some degree of HIV-associated neurocognitive disorder, due to the presence of the blood-brain barrier restricting drugs from crossing into the central nervous system and treating the viral reservoir there. One way to circumvent this is the nose-to-brain pathway. This pathway can also be accessed via a facial intradermal injection. Certain parameters can increase delivery via this route, including using nanoparticles with a positive zeta potential and an effective diameter of 200 nm or less. Microneedle arrays offer a minimally invasive, pain-free alternative to traditional hypodermic injections. This study shows the formulation of nanocrystals of both rilpivirine (RPV) and cabotegravir, followed by incorporation into separate microneedle delivery systems for application to either side of the face. Following an in vivo study in rats, delivery to the brain was seen for both drugs. For RPV, a C_max was seen at 21 days of 619.17 ± 73.32 ng/g, above that of recognised plasma IC90 levels, and potentially therapeutically relevant levels were maintained for 28 days. For CAB, a C_max was seen at 28 days of 478.31 ± 320.86 ng/g, and while below recognised 4IC90 levels, does indicate that therapeutically relevant levels could be achieved by manipulating final microaaray patch size in humans.

Development and Evaluation of an Innovative Approach Using Niosomes Based Polymeric Microneedles to Deliver Dual Antioxidant Drugs

Ascorbic acid (AA) and caffeine (CAFF) work to protect cells from ultraviolet (UV) radiation and slow down the photoaging process of the skin. However, cosmetic application of AA and CAFF is limited due to poor penetration across the skin and rapid oxidation of AA. The aim of this study was to design and evaluate the dermal delivery of dual antioxidants utilizing microneedles (MNs) loaded with AA and CAFF niosomes. The niosomal nanovesicles were prepared using the thin film method and had particle sizes ranging from 130.6-411.2 nm and a negative Zeta potential of around -35 mV. The niosomal formulation was then combined with polyvinylpyrrolidone (PVP) and polyethylene glycol 400 (PEG 400) to create an aqueous polymer solution. The best skin deposition of AA and CAFF was achieved with the formulation containing 5% PEG 400 (M3) and PVP. Furthermore, the role of AA and CAFF as antioxidants in preventing cancer formation has been well-established. Here we validated the antioxidant properties of ascorbic acid (AA) and caffeine (CAFF) in a novel niosomal formulation referred to as M3 by testing its ability to prevent H₂O₂-indued cell damage and apoptosis in MCF-7 breast cancer cells. Results showed that M3 was able to shield MCF-7 cells from H₂O₂ induced damage at concentrations below 2.1 µg/mL for AA and 1.05 µg/mL for CAFF, and also exhibited anticancer effects at higher concentrations of 210 µg/mL for AA and 105 µg/mL. The formulations were stable for two months at room temperature in terms of moisture and drug content. The use of MNs and niosomal carriers could be a promising approach for dermal delivery of hydrophilic drugs like AA and CAFF.

Preclinical study models of psoriasis: State-of-the-art techniques for testing pharmaceutical products in animal and nonanimal models

Local and systemic treatments exist for psoriasis, but none can do more than control its symptoms because of its numerous unknown mechanisms. The lack of validated testing models or a defined psoriatic phenotypic profile hinders antipsoriatic drug development. Despite their intricacy, immune-mediated diseases have no improved and precise treatment. The treatment actions may now be predicted for psoriasis and other chronic hyperproliferative skin illnesses using animal models. Their findings confirmed that a psoriasis animal model could mimic a few disease conditions. However, their ethical approval concerns and inability to resemble human psoriasis rightly offer to look for more alternatives. Hence, in this article, we have reported various cutting-edge techniques for the preclinical testing of pharmaceutical products for the treatment of psoriasis.

Use of 3D applicator for intranasal microneedle arrays for combinational therapy in migraine

The objective of current research work was to fabricate dissolving microneedles combining ergotamine and caffeine for synergistic action using controlled release kinetics with better permeability. The method of preparation for microneedles utilized multiple emulsion (w/o/w) approach by solvent-diffusion-evaporation process wherein the nano-emulsion of ergotamine and caffeine prepared using PLGA polymer and PVA as a stabilizer. The PLGA nanospheres were further loaded in polymer matrix of PVA and PVP K-90 and the final mixture poured in sterile silicon molds of microneedles. The PLGA nanospheres exhibited particle size in narrow range of 280.34 ± 6.61 to 416.0 ± 9.67 nm and good colloidal stability with negative zeta potential ranging between -19.08 ± 8.77 to -22.49 ± 8.09 mV. Higher entrapment efficiency (86.21 ± 4.52 %) for ergotamine and controlled release pattern (49.79 ± 4.16 % at 48 h) displayed by PLGA nanospheres. Similarly, the dissolving microneedles loaded with PLGA nanospheres showed controlled release pattern for in-vitro and ex-vivo drug release studies with 52.01 ± 5.71 % for ERM and 87.04 ± 2.44 % for CFE at 48 h whereas ex-vivo release studies illustrated similar results of 51.08 ± 3.56 % for ERM and 69.2 ± 2.16 % for CFE. The anti-hyperalgesic capability of microneedles was verified by the acetic acid writhing test, and the non-toxicity of synthetic microneedles was confirmed by histopathology and serotonin toxicity studies. The novel 3D applicator effectively delivered the microneedle array into the nasal cavity for systemic action. Therefore, the fabricated rapid dissolving microneedles combining two drugs ergotamine and caffeine with use of 3D applicator proved to be a coherent technique for intranasal delivery of ergotamine in the treatment of migraine.

State of the Art in Constructing Gas-Propelled Dissolving Microneedles for Significantly Enhanced Drug-Loading and Delivery Efficiency

Dissolving microneedles (MNs) have emerged as a promising transdermal delivery system, as they integrate the advantages of both injection and transdermal preparations. However, the low drug-loading and limited transdermal delivery efficiency of MNs severely hinder their clinical applications. Microparticle-embedded gas-propelled MNs were developed to simultaneously improve drug-loading and transdermal delivery efficiency. The effects of mold production technologies, micromolding technologies, and formulation parameters on the quality of gas-propelled MNs were systematically studied. Three-dimensional printing technology was found to prepare male mold with the highest accuracy, while female mold made from the silica gel with smaller Shore hardness could obtain a higher demolding needle percentage (DNP). Vacuum micromolding with optimized pressure was superior to centrifugation micromolding in preparing gas-propelled MNs with significantly improved DNP and morphology. Moreover, the gas-propelled MNs could achieve the highest DNP and intact needles by selecting polyvinylpyrrolidone K30 (PVP K30), polyvinyl alcohol (PVA), and potassium carbonate (K2CO3): citric acid (CA) = 0.15:0.15 (w/w) as the needle skeleton material, drug particle carrier, and pneumatic initiators, respectively. Moreover, the gas-propelled MNs showed a 1.35-fold drug loading of the free drug-loaded MNs and 1.19-fold cumulative transdermal permeability of the passive MNs. Therefore, this study provides detailed guidance for preparing MNs with high productivity, drug loading, and delivery efficiency.

Nanosuspensions technology as a master key for nature products drug delivery and In vivo fate

The drug nanosuspensions is a universal formulation approach for improved drug delivery of hydrophobic drugs and one the most promising approaches for increasing the biopharmaceutical performance of poorly water-soluble drug substances, especially for nature products. This review aimed to summarize the nanosuspensions preparation approaches and the main technological difficulties encountered in nanosuspensions development, such as guidelines for stabilizers screening, in vivo fate of the intravenously administrated nanosuspensions, and how to realize the intravenously target delivery was reviewed. Furthermore, challenges of nanosuspensions for the nature products delivery also was discussed and commented. Therefore, it hoped to provide reference and assistance for the nanosuspensions production, stabilizers usage, and predictability of in vivo fate and controllability of targeting delivery of the nature products nanosuspensions.

Reactive Oxygen Species-Responsive Gel-Based Microneedle Patches for Prolonged and Intelligent Psoriasis Management

Psoriasis is an inflammatory skin disease. Microneedle (MN) patches can improve psoriasis treatment outcomes by increasing local drug content in the skin. As psoriasis frequently relapses, developing intelligent MN-based drug delivery systems with prolonged therapeutic drug levels and improved treatment efficiency is of great significance. Here, we designed detachable H₂O₂-responsive gel-based MN patches containing methotrexate (MTX) and epigallocatechin gallate (EGCG) by using EGCG as both cross-linkers for needle-composited materials and anti-inflammatory drugs. The gel-based MNs had dual-mode drug release kinetics, which quickly released MTX diffusively and sustainably released EGCG in an H₂O₂-responsive way. Compared with dissolving MNs, the gel-based MNs extended skin retention of EGCG, leading to prolonged reactive oxygen species (ROS) scavenging effects. The ROS-responsive MN patches that transdermally delivered antiproliferative and anti-inflammatory drugs improved treatment outcomes in both psoriasis-like and prophylactic psoriasis-like animal models.

Enhanced skin drug delivery using dissolving microneedles: a potential approach for the management of skin disorders

INTRODUCTION

For decades, finding effective long-term or disease-modifying treatments for skin disorders has been a major focus of scientists. The conventional drug delivery systems showed poor efficacy with high doses and are associated with side effects, which lead to challenges in adherence to therapy. Therefore, to overcome the limitations of conventional drug delivery systems, drug delivery research has focused on topical, transdermal, and intradermal drug delivery systems. Among all, the dissolving microneedles have gained attention with a new range of advantages of drug delivery in skin disorders such as breaching skin barriers with minimal discomfort and its simplicity of application to the skin, which allows patients to administer it themselves.

AREAS COVERED

This review highlighted the insights into dissolving microneedles for different skin disorders in detail. Additionally, it also provides evidence for its effective utilization in the treatment of various skin disorders. The clinical trial status and patents for dissolving microneedles for the management of skin disorders are also covered.

EXPERT OPINION

The current review on dissolving microneedles for skin drug delivery is accentuating the breakthroughs achieved so far in the management of skin disorders. The output of the discussed case studies anticipated that dissolving microneedles can be a novel drug delivery strategy for the long-term treatment of skin disorders.

Hydrogel-forming microarray patch mediated transdermal delivery of tetracycline hydrochloride

Antibiotic resistance is one of the most serious health problems today and is expected to worsen in the coming decades. It has been suggested that antibiotic administration routes that bypass the human gut could potentially tackle this problem. In this work, an antibiotic hydrogel-forming microarray patch (HF-MAP) system, which can be used as an alternative antibiotic delivery technology, has been fabricated. Specifically, poly(vinyl alcohol)/poly(vinylpyrrolidone) (PVA/PVP) microarray showed excellent swelling properties with >600% swelling in PBS over 24 h. The tips on the HF-MAP were proven to be able to penetrate a skin model which is thicker than stratum corneum. The antibiotic (tetracycline hydrochloride) drug reservoir was mechanically robust and dissolved completely in an aqueous medium within a few minutes. In vivo animal studies using a Sprague Dawley rat model showed antibiotic administration using HF-MAP achieved a sustained release profile, in comparison with animals receiving oral gavage and intravenous (IV) injection, with a transdermal bioavailability of 19.1% and an oral bioavailability of 33.5%. The maximum drug plasma concentration for HF-MAP group reached 7.40 ± 4.74 μg/mL at 24 h, whereas the drug plasma concentration for both oral (5.86 ± 1.48 μg/mL) and IV (8.86 ± 4.19 μg/mL) groups peaked soon after drug administration and had decreased to below the limit of detection at 24 h. The results demonstrated that antibiotics can be delivered by HF-MAP in a sustained manner.

Combination of Dissolving Microneedles with Nanosuspension and Co-Grinding for Transdermal Delivery of Ketoprofen

Ketoprofen is an anti-inflammatory agent that may cause gastric irritation if administered orally. Dissolving microneedles (DMN) can be a promising strategy to overcome this issue. However, ketoprofen has a low solubility; therefore, it is essential to enhance its solubility using certain methods, namely nanosuspension (NS) and co-grinding (CG). This research aimed to formulate DMN containing ketoprofen-loaded NS and CG. Ketoprofen NS was formulated with poly(vinyl alcohol) (PVA) at concentrations of 0.5%, 1%, and 2%. CG was prepared by grinding ketoprofen with PVA or poly(vinyl pyrrolidone) (PVP) at different drug–polymer ratios. The manufactured ketoprofen-loaded NS and CG were evaluated in terms of their dissolution profile. The most promising formulation from each system was then formulated into microneedles (MNs). The fabricated MNs were assessed in terms of their physical and chemical properties. An in vitro permeation study using Franz diffusion cells was also carried out. The most promising MN-NS and MN-CG formulations were F4-MN-NS (PVA 5%-PVP 10%), F5-MN-NS (PVA 5%-PVP 15%), F8-MN-CG (PVA 5%-PVP 15%), and F11-MN-CG (PVA 7.5%-PVP 15%), respectively. The cumulative amounts of drug permeated after 24 h for F5-MN-NS and F11-MN-CG were 3.88 ± 0.46 µg and 8.73 ± 1.40 µg, respectively. In conclusion, the combination of DMN with nanosuspension or a co-grinding system may be a promising strategy for delivering ketoprofen transdermally.

Nanocrystals as an emerging nanocarrier for the management of dermatological diseases

Skin conditions are amongst the most prevalent health issues in the world and come with a heavy economic, social, and psychological burden. Incurable and chronic skin conditions like eczema, psoriasis, fungal infections are linked to major morbidity in the manner of physical pain and a reduction in quality life of patients. Several drugs have difficulties for penetrating the skin due to the barrier mechanism of the skin layers and the incompatible physicochemical characteristics of the drugs. This has led to the introduction of innovative drug delivery methods. Currently, formulations depend on nanocrystals have indeed been researched for topical administration of drugs and have resulted in enhanced skin penetration. This review focuses on skin penetration barriers, modern methods to enhance topical distribution, and the use of nanocrystals to overcome these barriers. By means of mechanisms such as adherence to skin, creation of diffusional corona, targeting of hair follicles, and the generation of a greater concentration gradient throughout the skin, nanocrystals could enhance transport across the skin. Scientists working on product formulations incorporating chemicals that are "challenging-to-deliver" topically may find the most current findings to be of relevance.

Microneedles as a momentous platform for psoriasis therapy and diagnosis: A state-of-the-art review

Psoriasis is a chronic, autoimmune, and non-communicable skin disease with a worldwide prevalence rate of 2-3%, creating an economic burden on global health. Some significant risk factors associated with psoriasis include genetic predisposition, pathogens, stress, medications, etc. In addition, most patients with psoriasis should also deal with comorbidities such as psoriatic arthritis, inflammatory bowel diseases, cardiovascular diseases, and psychological conditions, including suicidal thoughts. Based on its severity, the treatment approach for psoriasis is categorised into three types, i.e., topical therapy, systemic therapy, and phototherapy. Topical therapy for mild-to-moderate psoriasis faces several issues, such as poor skin permeability, low skin retention of drug formulation, greasy texture of topical vehicle, lack of controlled release, and so on. On the other arrow, systemic therapy via an oral or parenteral route of drug administration involves numerous drawbacks, including first-pass hepatic metabolism, hepatotoxicity, gastrointestinal disturbances, needle pain and phobia, and requirement of healthcare professional to administer the drug. To overcome these limitations, researchers devised a microneedle-based drug delivery system for treating mild-to-moderate and moderate-to-severe psoriasis. A single microneedle system can deliver the anti-psoriatic drugs either locally (topical) or systemically (transdermal) by adjusting the needle height without involving any pain. In this contemplate, the current review provides concise information on the pathophysiology, risk factors, and comorbidities of psoriasis, followed by their current treatment approaches and limitations. Further, it meticulously discusses the potential of microneedles in psoriasis therapy and diagnosis, along with descriptions of their patents and clinical trials.

Where Microneedle Meets Biomarkers: Futuristic Application for Diagnosing and Monitoring Localized External Organ Diseases

Extracellular tissue fluids are interesting biomatrices that have recently attracted scientists' interest. Many significant biomarkers for localized external organ diseases have been isolated from this biofluid. In the diagnostic and disease monitoring context, measuring biochemical entities from the fluids surrounding the diseased tissues may give more important clinical value than measuring them at a systemic level. Despite all these facts, pushing tissue fluid-based diagnosis and monitoring forward to clinical settings faces one major problem: its accessibility. Most extracellular tissue fluid, such as interstitial fluid (ISF), is abundant but hard to collect, and the currently available technologies are invasive and expensive. This is where novel microneedle technology can help tackle this significant obstacle. The ability of microneedle technology to minimally invasively access tissue fluid-containing biomarkers will enable ISF and other tissue fluid utilization in the clinical diagnosis and monitoring of localized diseases. This review attempts to present the current pursuit of the application of microneedle systems as a diagnostic and monitoring platform, along with the recent progress of biomarker detection in diagnosing and monitoring localized external organ diseases. Then, the potential use of various microneedles in future clinical diagnostics and monitoring of localized diseases is discussed by presenting the currently studied cases.

Dissolving microneedles for effective and painless intradermal drug delivery in various skin conditions: A systematic review

Intra- and transdermal administration of substances via percutaneous injection is effective but considered painful, and inconvenient in addition to bringing forth biohazardous waste material. In contrast to injection, topical drug application, which includes ointments, creams and lotions, increases the local drug load. Moreover, it has reduced side effects compared to systemic administration. However, the epidermis poses a barrier to high molecular weight substances, limiting the delivery efficiency. Dissolving microneedles (DMN) are hydrophilic, mostly polymer-based constructs that are capable of skin penetration and were developed to provide painless and direct dermal drug delivery. This systematic review provides a comprehensive overview of the available clinical evidence for the use of DMN to treat various skin conditions. According to the PRISMA statement, a systematic search for articles on the use of DMN for dermatological indications was conducted on three different databases (Pubmed, Embase, and the Cochrane library). Only human clinical trials were considered. Qualitative assessment was done by two separate reviewers using the Cochrane risk of bias (RoB 2) and Chambers' criteria assessment tools. The search yielded 1090 articles. After deduplication and removal of ineligible records, 889 records were screened on title and abstract. Full text screening was done for 18 articles and ultimately 17 articles were included of which 15 were randomized controlled trials and two were case series. The quality assessment showed that the majority of included studies had low to no risk of bias. Clinical data supports that DMN are an excellent, effective, and pain free drug delivery method for multiple dermatological disorders including skin aging, hyperpigmentation, psoriasis, warts, and keloids by supplying a painless and effective vehicle for intradermal/intralesional drug administration. Microneedle technology provides a promising non- to minimally-invasive alternative to percutaneous injection.

Formulation and Evaluation of Niosomal Alendronate Sodium Encapsulated in Polymeric Microneedles: In Vitro Studies, Stability Study and Cytotoxicity Study

The aim of this study is to design and evaluate a transdermal delivery system for alendronate sodium (ALS) loaded with nanocarrier to improve its permeability and prolong its release. This is due to its low bioavailability, potential gastrointestinal side effects, and the special administration needed for the oral dosage form of ALS. When using the ether injection method, various niosomal formulations were produced. Size of the particles, polydispersity index (PDI), surface charge (ZP), drug entrapment efficiency (EE), and in vitro release were used to characterize the resulting niosomes. The size of niosomes ranged between 99.6 ± 0.9 and 464.3 ± 67.6 nm, and ZP was from −27.6 to −42.27 mV. The niosomal formulation was then loaded to aqueous polymer solution of 30% polyvinyl pyrrolidone (PVP) (MN-1), 30% PVP with 15% poly(vinyl alcohol) (PVA) (2:1) (MN-2), and 30% PVP with 15% PVA (1:1) (MN-3). The cumulative amount of ALS (Q) was in the following order: MN-1 > MN-2 > MN-3. All formulations in this study were stable at room temperature over two months, in terms of moisture content and drug content. In conclusion, a transdermal delivery of ALS niosomes combined in microneedles (MNs) was successfully prepared to provide sustained release of ALS.

Tacrolimus nanocrystals microneedle patch for plaque psoriasis

Plaque psoriasis is characterized by an abnormal thickening of the epidermis, which causes great difficulties for traditional topical drug delivery. Microneedles can pierce the thickened epidermis and deliver drugs to the skin for psoriasis treatment. Tacrolimus is a poorly water-soluble immunosuppressant used for the treatment of psoriasis. In this study, tacrolimus (TAC) nanocrystals (NCs) were produced using a bottom-up technique that dispersed TAC into a sodium hyaluronate-based microneedle patch (MNP), and its therapeutic efficacy was evaluated. The average particle size of the TAC NCs was 259.6 ± 2.3 nm. The mechanical strength of the microneedles was 0.41 ± 0.06 N/needle, which was sufficient to penetrate psoriatic skin. Microneedles were detached from the substrate 10 min after insertion into the psoriasis skin with an insertion depth of 258.8 ± 14.4 μm. The intradermal retention of the MNP (8.40 ± 0.33 μg/cm²) was six times that of the commercial ointment (1.40 ± 0.12 μg/cm²). In pharmacodynamic experiments, results indicated improvement in the phenotypic and histopathological features and reduction in the level of TNF-α, IL-17A, and IL-23 of psoriatic skin treated with TAC NCs MNP. Therefore, MNP loaded with TAC NCs may be a promising approach for psoriasis treatment.

Metronidazole nanosuspension loaded dissolving microarray patches: An engineered composite pharmaceutical system for the treatment of skin and soft tissue infection

Bacteroides fragilis is one of the most common causative group of microorganisms that is associated with skin and soft tissue infections (SSTI). Metronidazole (MTZ) is the drug of choice used in the treatment of SSTI caused by the bacterium. However, owing to its physiochemical properties, MTZ have limited skin permeation, which render the drug unsuitable for the treatment of deep-rooted SSTIs. One strategy to overcome this limitation is to reformulate MTZ into nanosuspension which will then be loaded into dissolving microarray patches (MAPs) for the treatment of SSTIs caused by B. fragilis. Herein, we report for the first time on the preparation and optimisation of MAP loaded with MTZ nanosuspension (MTZ-NS). After screening a range of polymeric surfactants, we identified that Soluplus® resulted in the formation of MTZ-NS with the smallest particle size (115 nm) and a narrow PDI of 0.27. Next, the MTZ-NS was further optimised using a design of experiments (DoE) approach. The optimised MTZ-NS was then loaded into dissolving MAPs with varying MTZ-NS content. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell proliferation assays along with LIVE/DEAD™ staining on the 3T3L1 cell line showed that the MTZ-NS loaded dissolving MAPs displayed minimal toxicity and acceptable biocompatibility. In vitro dermatokinetic studies showed that the MTZ-NS loaded MAPs were able to deliver the nitroimidazole antibiotic across all strata of the skin resulting in a delivery efficiency of 95 % after a 24-hour permeation study. Lastly, agar plating assay using bacterial cultures of B. fragilis demonstrated that MTZ-NS loaded MAP resulted in complete bacterial inhibition in the entire plate relative to the control group. Should this formulation be translated into clinical practice, this pharmaceutical approach may provide a minimally invasive strategy to treat SSTIs caused by B. fragilis.