Design and Evaluation of Dissolving Microneedles for Enhanced Dermal Delivery of Propranolol Hydrochloride

Design and formulation of fast-dissolving microneedles for the rapid transdermal delivery of lorazepam

This study investigates lorazepam-loaded dissolving microneedles (LMNs) as a fast-acting and minimally invasive treatment for status epilepticus. The LMNs were developed using a micro-moulding technique with an optimised combination of PVP K30, Dextran 40 and Pullulan. Their stability was confirmed through Fourier transform infra-red (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The Parafilm® membrane insertion test demonstrated 100% penetration efficiency, verifying their ability to effectively pierce the skin. Scanning electron microscopy (SEM) imaging revealed well-defined microneedles with precise dimensions (800 µm height, 200 µm base and 500 µm pitch). The LMNs rapidly dissolved in the subdermal layer of porcine skin. An ex vivo drug diffusion study showed that 3-5% of the encapsulated lorazepam was released within 30 min, with a cumulative release of 79.3% over 24 h. An acute dermal irritation study confirmed the biocompatibility and skin tolerance of the LMNs. Additionally, an in vivo anti-convulsant efficacy study in Albino Wistar rats subjected to maximal electroshock seizures demonstrated significant anticonvulsant effects (p < .05), confirming efficient systemic delivery of lorazepam. These findings highlight LMNs as a rapid-acting, non-invasive transdermal drug delivery system for managing status epilepticus, particularly in ambulatory care settings.

Transdermal delivery of resveratrol loaded solid lipid nanoparticle as a microneedle patch: a novel approach for the treatment of Parkinson's disease

Parkinson's disease (PD), affecting millions of people worldwide and expected to impact 10 million by 2030, manifests a spectrum of motor and non-motor symptoms linked to the decline of dopaminergic neurons. Current therapies manage PD symptoms but lack efficacy in slowing disease progression, emphasizing the urgency for more effective treatments. Resveratrol (RSV), recognized for its neuroprotective and antioxidative properties, encounters challenges in clinical use for PD due to limited bioavailability. Researchers have investigated lipid-based nanoformulations, specifically solid lipid nanoparticles (SLNs), to enhance RSV stability. Oral drug delivery via SLNs faces obstacles, prompting exploration into transdermal delivery using SLNs integrated with microneedles (MNs) for improved patient compliance. In this study, an RSV-loaded SLNs (RSV -SLNs) incorporated into the MN patch was developed for transdermal RSV delivery to improve its stability and patient compliance. Characterization studies demonstrated favorable physical properties of SLNs with a sustained drug release profile of 78.36 ± 0.74%. The developed MNs exhibited mechanical robustness and skin penetration capabilities. Ex vivo permeation studies displayed substantial drug permeation of 68.39 ± 1.4% through the skin. In an in vivo pharmacokinetic study, the RSV-SLNs delivered through MNs exhibited a significant increase in Cmax, Tmax, and AUC0 - t values, alongside a reduced elimination rate in blood plasma in contrast to the administration of pure RSV via MNs. Moreover, an in vivo study showcased enhanced behavioral functioning and increased brain antioxidant levels in the treated animals. In-vivo skin irritation study revealed no signs of irritation till 24 h which permits long-term MNs application. Histopathological analysis showed notable changes in the brain regions of the rat, specifically the striatum and substantia nigra, after the completion of the treatment. Based on these findings, the development of an RSV-SLN loaded MNs (RSVSNLMP) patch presents a novel approach, with the potential to enhance the drug's efficiency, patient compliance, and therapeutic outcomes for PD, offering a promising avenue for advanced PD therapy.

Recent Advances in Propranolol Hydrochloride Formulations for the Treatment of Infantile Hemangiomas

Infantile hemangiomas (IHs) are a kind of skin soft tissue benign tumors in infants, with a high incidence rate and significant harm. Rapid early proliferation can cause severe cosmetic deformities and organ development disorders. Propranolol Hydrochloride (PRH), a non-selective adrenergic β-receptor blocker, has become the first-line treatment for IHs due to its good efficacy and safety compared to other drugs. To further improve the bioavailability of PRH, deliver it more safely and effectively to the lesion site, and enhance patient compliance, researchers are continually developing new PRH formulations for the treatment of IHs. This article briefly introduced the pathogenesis of IHs and the therapeutic mechanism of PRH. It also provided a detailed overview of various new PRH formulations developed over the past 12 years for the treatment of IHs, including improved oral formulations, topical creams, gels, liposomes/nanoparticles, transdermal patches, microneedles, and targeted injectable formulations. This article summarized the development prospects and technical challenges of these new formulations. It aims to provide a comprehensive review of recent advances in new propranolol formulations and technologies for treating IHs, offering a reference for further research and application. At the same time, it is hoped that various new formulations of PRH can be safely and efficiently used in clinical practice in the future.

Microneedle-based arrays - Breakthrough strategy for the treatment of bacterial and fungal skin infections

Currently, fungal and bacterial skin infections rank among the most challenging public health problems due to the increasing prevalence of microorganisms and the development of resistance to available drugs. A major issue in treating these infections with conventional topical medications is the poor penetration through the stratum corneum, the outermost layer of the skin. The concept of microneedles seems to be a future-proof approach for delivering drugs directly into deeper tissues. By bypassing the skin barrier, microneedle systems allow therapeutic substances to reach deeper layers more efficiently, significantly improving treatment outcomes. Nonetheless, the primary challenges regarding the effectiveness of microneedles involve selecting the appropriate size and shape, along with polymer composition and fabrication technology, to enable controlled and efficient drug release. This review offers a comprehensive overview of the latest knowledge on microneedle types and manufacturing techniques, highlighting their potential effectiveness in treating bacterial and fungal skin infections. It includes updated statistics on infection prevalence and provides a detailed examination of common bacterial and fungal diseases, focusing on their symptoms, causative species, and treatment methods. Additionally, the review addresses safety considerations, regulatory aspects, and future perspectives for microneedle-based therapeutic systems. It also underscores the importance of industrialization and clinical translation efforts, emphasizing the significant potential of microneedle technology for advancing medical applications.

Seeing through the skin: Optical methods for visualizing transdermal drug delivery with microneedles

Optical methods play a pivotal role in advancing transdermal drug delivery research, particularly with the emergence of microneedle technology. This review presents a comprehensive analysis of optical methods used in studying transdermal drug delivery facilitated by microneedle technology. Beginning with an introduction to microneedle technology and skin anatomy and optical properties, the review explores the integration of optical methods for enhanced visualization. Optical imaging offers key advantages including real-time drug distribution visualization, non-invasive skin response monitoring, and quantitative drug penetration analysis. A spectrum of optical imaging modalities ranging from conventional dermoscopy and stereomicroscopy to advance techniques as fluorescence microscopy, laser scanning microscopy, in vivo imaging system, two-photon microscopy, fluorescence lifetime imaging microscopy, optical coherence tomography, Raman microspectroscopy, laser speckle contrast imaging, and photoacoustic microscopy is discussed. Challenges such as resolution and depth penetration limitations are addressed alongside potential breakthroughs and future directions in optical techniques development. The review underscores the importance of bridging the gap between preclinical and clinical studies, explores opportunities for integrating optical imaging and chemical sensing methods with drug delivery systems, and highlight the importance of non-invasive "optical biopsy" as a valuable alternative to conventional histology. Overall, this review provides insight into the role of optical methods in understanding transdermal drug delivery mechanisms with microneedles.

Development and optimization of hydrogel-forming microneedles fabricated with 3d-printed molds for enhanced dermal diclofenac sodium delivery: a comprehensive in vitro, ex vivo, and in vivo study

With the developing manufacturing technologies, the use of 3D printers in microneedle production is becoming widespread. Hydrogel-forming microneedles (HFMs), a variant of microneedles, demonstrate distinctive features such as a high loading capacity and controlled drug release. In this study, the conical microneedle master molds with approximately 500 μm needle height and 250 μm base diameter were created using a Stereolithography (SLA) 3D printer and were utilized to fabricate composite HFMs containing diclofenac sodium. Using Box-Behnken Design, the effects of different polymers on swelling index and mechanical strength of the developed HFMs were evaluated. The optimum HFMs were selected according to experimental design results with the aim of the highest mechanical strength with varying swelling indexes, which was needed to use 20% Gantrez S97 and 0.1% (F22), 0.42% (F23), and 1% (F24) hyaluronic acid. The skin penetration and drug release properties of the optimum formulations were assessed. Ex vivo studies were conducted on formulations to determine drug penetration and accumulation. F24, which has the highest mechanical strength and optimized swelling index, achieved the highest drug accumulation in the skin tissue (17.70 ± 3.66%). All optimum HFMs were found to be non-cytotoxic by the MTT cell viability test (> 70% cell viability). In in vivo studies, the efficacy of the F24 was assessed for the treatment of xylene-induced ear edema by contrasting it to the conventional dosage form. It was revealed that HFMs might be an improved replacement for conventional dosage forms in terms of dermal diseases such as actinic keratosis.

An Invisible Dermal Nanotattoo-Based Smart Wearable Sensor for eDiagnostics of Jaundice

Despite substantial progress in the diagnosis of jaundice/hyperbilirubinemia as the most common disease and cause of hospitalization of newborns, on the eve of Industry/Healthcare 5.0, the development of accurate and reliable wearable diagnostic sensors for noninvasive smart monitoring of bilirubin (BIL) is still in high demand. Aiming to fabricate a smart wearable sensor for early diagnosis of neonatal jaundice and its therapeutic monitoring, we here report a fluorescent dermal nanotattoo that further coupled with an IoT-integrated wearable optoelectronic reader for minimally invasive, continuous, and real-time monitoring of BIL in interstitial fluid. Selective recovery of quenched fluorescence of the dermal tattoo sensor, composed of biocompatible dissolving/hydrogel microneedles loaded with fluorescent carbon quantum dots, upon blue light exposure used for jaundice phototherapy was utilized for highly selective BIL sensing. The fascinating features of our developed smart wearable tattoo sensor and its successful results with high correlation with blood BIL results make it a highly promising sensor for easy, minimally invasive, reliable, and smart eDiagnostics and continuous therapeutic eMonitoring of jaundice and other BIL-induced diseases at the point of care. We envision that the developed nanotattoo sensing bioplatform will inspire the development of future smart tattoo sensors in various diagnostic and monitoring scenarios.

Development of itraconazole ocular delivery system using β-cyclodextrin complexation incorporated into dissolving microneedles for potential improvement treatment of fungal keratitis

Itraconazole (ITZ) is one of the broad-spectrum antifungal agents for treating fungal keratitis. In clinical use, ITZ has problems related to its poor solubility in water, which results in low bioavailability when administered orally. To resolve the issue, we formulated ITZ into the inclusion complex (ITZ-IC) system using β-cyclodextrin (β-CD), which can potentially increase the solubility and bioavailability of ITZ. The molecular docking study has confirmed that the binding energy of ITZ with the β-CD was -5.0 kcal/mol, indicating a stable conformation of the prepared inclusion complex. Moreover, this system demonstrated that the inclusion complex could significantly increase the solubility of ITZ up to 4-fold compared to the pure drug. Furthermore, an ocular drug delivery system was developed through dissolving microneedle (DMN) using polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) as polymeric substances. The evaluation results of DMN inclusion complexes (ITZ-IC-DMN) showed excellent mechanical strength and insertion ability. In addition, ITZ-IC-DMN can dissolve rapidly upon application. The ex vivo permeation study revealed that 75.71% (equivalent to 3.79 ± 0.21 mg) of ITZ was permeated through the porcine cornea after 24 h. Essentially, ITZ-IC-DMN exhibited no signs of irritation in the HET-CAM study, indicating its safety for application. In conclusion, this study has successfully developed an inclusion complex formulation containing ITZ using β-CD in the DMN system. This approach holds promise for enhancing the solubility and bioavailability of ITZ through ocular administration.

Microneedles mediated-dermal delivery of Vitamin C: Formulation, characterization, cytotoxicity, and enhancement of stability

Vitamin C (VIT C) is an antioxidant that prevents skin aging. Although dermal delivery is one of the most effective routes to transport VIT C to the skin, the impact of this route can be limited by the barrier function of the stratum corneum (SC). Additionally, VIT C rapidly oxidized and degraded under light and temperature. Therefore, this study provides an approach to utilizing microneedles (MNs) to improve the dermal delivery of VIT C and enhance its stability by incorporating a stabilizing system of ethylenediaminetetraacetic acid (EDTA) and sodium metabisulfite (Meta) within the MNs. Vitamin C microneedles (VIT C MNs) were fabricated using different biodegradable polymers and various concentrations of EDTA/Meta. VIT C MNs were evaluated for morphology, VIT C content, mechanical properties, dissolution rate, needles' insertion, physicochemical properties, ex vivo permeation, viscosity of VIT C polymeric solutions, cytotoxicity, and stability. The results showed that VIT C MNs were uniform and mechanically strong. The recovery of VIT C in MNs was 88.3-90.0 %. The dissolution rate of MNs was <30 min. The flux of VIT C varied based on the composition of MNs. VIT C MNs demonstrated safety against human dermal fibroblasts. VIT C MNs with EDTA/Meta (0.1/0.3 %) were stable under different storage conditions for two months. In conclusion, VIT C MNs were successfully developed using biodegradable polymers, and the stabilizing system (EDTA/META) provided a stable dermal delivery system for VIT C to protect skin from aging.

Development of dissolving microneedles loaded with fucoidan for enhanced anti-aging activity: An in vivo study in mice animal model

Skin aging occurs naturally as essential skin components gradually decline, leading to issues such as fine lines, wrinkles, and pigmentation. Fucoidan, a natural bioactive compound, holds potential for addressing these age-related concerns. However, its hydrophilic nature and substantial molecular weight hinder its absorption into the skin. In this study, we utilized polyvinyl pyrrolidone K30 (PVP) and polyvinyl alcohol (PVA) as polymers to fabricate dissolving microneedles loaded with fucoidan (DMN-F). The DMN-F formulations were examined for physical characteristics, stability, permeability, toxicity, and efficacy in animal models. These formulations exhibited consistent polymer blends with a conical structure and uniform cone-shaped design. Microneedle structure and penetration capability gradually decreased with increasing fucoidan concentration, with storage recommended at approximately 33 % relative humidity (RH). Ex vivo studies showed that DMN-F efficiently delivered up to 95.03 ± 2.36 % of the total fucoidan concentration into the skin. In vivo investigations revealed that DMN-F effectively reduced wrinkles, improved skin elasticity, maintained moisture levels, and increased epidermal thickness. Histological images provided additional evidence of DMN-F's positive effects on these aging parameters. The results confirm that the DMN-F formulation effectively delivers fucoidan into the skin, allowing it to treat and mitigate signs of aging.

Fabrication and Characterization of Dissolving Microneedles Containing Oryza sativa L. Extract Complex for Enhancement of Transfollicular Delivery

Dissolving microneedles are extensively applied in drug delivery systems to enhance penetration into the skin. In this study, dissolving microneedles fabricated from polyvinylpyrrolidone K90 (PVP-K90) and hydroxypropylmethyl cellulose (HPMC) E50 in different ratios were characterized. The selected formulations incorporated Oryza sativa L. extract complex and its characteristics, transfollicular penetration, and safety were observed. The microneedles, fabricated from PVP K90: HPMC E50 in a ratio of 25:5 (P25H5) and 20:10 (P20H10), revealed excellent morphological structure, proper mechanical strength, and excellent skin insertion. P25H5 microneedles exhibited faster dissolution than P20H10 microneedles. Microneedles containing Oryza sativa L. extract complex showed excellent morphological structure via scanning electron microscopy but decreased mechanical strength. P25H5-O, which exhibited an effective ability to enter skin, was selected for further investigation. This microneedle formulation had a high percentage of drug-loading content, enhanced skin penetration via the transfollicular route, and was safe for keratinocytes. As a result, the dissolving microneedle containing Oryza sativa L. extract complex can be used to enhance transfollicular delivery through the skin with safety.

Rational Design of Human Hair Keratin-Driven Proteins for Hair Growth Promotion

Keratins, the most abundant proteins in human hair, are excellent hair nutrients for growth. However, the complex components of keratin extract hinder their mechanism investigation, and the pure recombinant keratin with poor solubility limited its hair growth promotion efficiency. Here, the water-soluble recombinant keratins (RKs) of K31 and K81 are rationally designed through QTY Code methodology, which are then used to fabricate the microneedles to study the effect of keratin on hair growth. Interestingly, it is discovered that more than 40% of the hair follicles (HFs) in the RK81QTY group entered the anagen on day 12 and the diameter of new hair is 15.10 ± 2.45 µm, which significantly promoted growth and development of HFs and improved new hair quality compared to RK31QTY. Water-soluble RKs significantly enhanced HFs activity and de novo regeneration of robust hairs compared to extract and minoxidil by upregulating the PI3K/AKT/Nf-κB signaling axis. These findings highlight the potential of designing solubilized recombinant keratins with distinct properties to improve therapeutical effects and open new avenues to designing keratin-based proteins.

Trilayer dissolving microneedle for transdermal delivery of minoxidil: a proof-of-concept study

Alopecia areata (AA) is a chronic autoimmune disease characterized by bald patches in certain areas of the body, especially the scalp. Minoxidil (MNX), as a first-line treatment of AA, effectively induces hair growth. However, oral and topical administration pose problems, including low bioavailability, risk of uncontrolled hair growth, and local side effects such as burning hair loss, and scalp irritation. In the latest research, MNX was delivered to the skin via microneedle (MN) transdermally. The MNX concentration was distributed throughout the needle so that drug penetration was reduced and had the potential to irritate. In this study, we formulated MNX into three-layer dissolving microneedles (TDMN) to increase drug penetration and avoid irritation. Physicochemical evaluation, parafilm, was used to evaluate the mechanical strength of TDMN and showed that TDMN could penetrate the stratum corneum. The ex-vivo permeation test showed that the highest average permeation result was obtained for TDMN2, namely 165.28 ± 31.87 ug/cm2, while for Minoxidil cream it was 46.03 ± 8.5 ug/cm2. The results of ex vivo and in vivo dermatokinetic tests showed that the amount of drug concentration remaining in the skin from the TDMN2 formula was higher compared to the cream preparation. The formula developed has no potential for irritation and toxicity based on the HET-CAM test and hemolysis test. TDMN is a promising alternative to administering MNX to overcome MNX problems and increase the effectiveness of AA therapy.

Determination of vat-photopolymerization parameters for microneedles fabrication and characterization of HPMC/PVP K90 dissolving microneedles utilizing 3D-printed mold

Three-dimensional (3D) printing serves as an alternative method for fabricating microneedle (MN) patches with a high object resolution. In this investigation, four distinct needle shapes: pyramid mounted over a long cube (shape A), cone mounted over a cylinder (shape B), pyramidal shape (shape C), and conical shape (shape D) were designed using computer-aided design (CAD) software with compensated bases of 350, 450 and 550 µm. Polylactic acid (PLA) biophotopolymer resin from eSun and stereolithography (SLA) 3D printer from Anycubic technology were used to print MN patches. The 3D-printed MN patches were employed to construct MN molds, and those molds were used to produce hydroxypropyl methylcellulose (HPMC) and polyvinyl pyrrolidone (PVP) K90 dissolving microneedles (DMNs). Various printing parameters, such as curing time, printing angle, and anti-aliasing (AA), were varied to evaluate suitable printing conditions for each shape. Furthermore, physical appearance, mechanical property, and skin insertion ability of HPMC/PVP K90 DMNs were examined. The results showed that for shape A and C, the suitable curing time and printing angle were 1.5 s and 30° while for shapes B and D, they were 2.0 s and 45°, respectively. All four shapes required AA to eliminate their stair-stepped edges. Additionally, it was demonstrated that all twelve designs of 3D-printed MN patches could be employed for fabricating MN molds. HPMC/PVP K90 DMNs with the needles of shape A and B exhibited better physicochemical properties compared to those of shape C and D. Particularly, both sample 9 and 10 displayed sharp needle without bent tips, coupled with minimal height reduction (< 10%) and a high percentage of blue dots (approximately 100%). As a result, 3D printing can be utilized to custom construct 3D-printed MN patches for producing MN molds, and HPMC/PVP K90 DMNs manufactured by those molds showed excellent physicochemical properties.

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 advances in nanomaterial-driven strategies for diagnosis and therapy of vascular anomalies

Nanotechnology has demonstrated immense potential in various fields, especially in biomedical field. Among these domains, the development of nanotechnology for diagnosing and treating vascular anomalies has garnered significant attention. Vascular anomalies refer to structural and functional anomalies within the vascular system, which can result in conditions such as vascular malformations and tumors. These anomalies can significantly impact the quality of life of patients and pose significant health concerns. Nanoscale contrast agents have been developed for targeted imaging of blood vessels, enabling more precise identification and characterization of vascular anomalies. These contrast agents can be designed to bind specifically to abnormal blood vessels, providing healthcare professionals with a clearer view of the affected areas. More importantly, nanotechnology also offers promising solutions for targeted therapeutic interventions. Nanoparticles can be engineered to deliver drugs directly to the site of vascular anomalies, maximizing therapeutic effects while minimizing side effects on healthy tissues. Meanwhile, by incorporating functional components into nanoparticles, such as photosensitizers, nanotechnology enables innovative treatment modalities such as photothermal therapy and photodynamic therapy. This review focuses on the applications and potential of nanotechnology in the imaging and therapy of vascular anomalies, as well as discusses the present challenges and future directions.

HPMC/PVP K90 Dissolving Microneedles Fabricated from 3D-Printed Master Molds: Impact on Microneedle Morphology, Mechanical Strength, and Topical Dissolving Property

Three-dimensional (3D) printing can be used to fabricate custom microneedle (MN) patches instead of the conventional method. In this work, 3D-printed MN patches were utilized to fabricate a MN mold, and the mold was used to prepare dissolving MNs for topical lidocaine HCl (L) delivery through the skin. Topical creams usually take 1-2 h to induce an anesthetic effect, so the delivery of lidocaine HCl from dissolving MNs can allow for a therapeutic effect to be reached faster than with a topical cream. The dissolving-MN-patch-incorporated lidocaine HCl was constructed from hydroxypropyl methylcellulose (HPMC; H) and polyvinyl pyrrolidone (PVP K90; P) using centrifugation. Additionally, the morphology, mechanical property, skin insertion, dissolving behavior, drug-loading content, drug release of MNs and the chemical interactions among the compositions were also examined. H51P2-L, H501P2-L, and H901P2-L showed an acceptable needle appearance without bent tips or a broken structure, and they had a low % height change (<10%), including a high blue-dot percentage on the skin (>80%). These three formulations exhibited a drug-loading content approaching 100%. Importantly, the composition-dependent dissolving abilities of MNs were revealed. Containing the lowest amount of HPMC in its formulation, H901P2-L showed the fastest dissolving ability, which was related to the high amount of lidocaine HCl released through the skin. Moreover, the results of an FTIR analysis showed no chemical interactions among the two polymers and lidocaine HCl. As a result, HPMC/PVP K90 dissolving microneedles can be used to deliver lidocaine HCl through the skin, resulting in a faster onset of anesthetic action.

Tiny titans- unravelling the potential of polysaccharides and proteins based dissolving microneedles in drug delivery and theranostics: A comprehensive review

In recent years, microneedles (MNs) have emerged as a promising alternative to traditional drug delivery systems in transdermal drug delivery. The use of MNs has demonstrated significant potential in improving patient acceptance and convenience while avoiding the invasiveness of traditional injections. Dissolving, solid, hollow, coated, and hydrogel microneedles are among the various types studied for drug delivery. Dissolving microneedles (DMNs), in particular, have gained attention for their safety, painlessness, patient convenience, and high delivery efficiency. This comprehensive review primarily focuses on different types of microneedles, fabrication methods, and materials used in fabrication of DMNs such as hyaluronic acid, chitosan, alginate, gelatin, collagen, silk fibroin, albumin, cellulose and starch, to list a few. The review also provides an exhaustive discussion on the applications of DMNs, including the delivery of vaccines, cosmetic agents, contraceptives, hormone and genes, and other therapeutic applications like for treating cancer, skin diseases, and diabetes, among others, are covered in this review. Additionally, this review highlights some of the DMN systems that are presently undergoing clinical trials. Finally, the review discusses current advances and trends in DMNs, as well as future prospective directions for this ground-breaking technology in drug delivery.

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.

Antilipogenesis Effect of Rutin-Loaded Liposomes Using a Microneedle Delivery System

Rutin, a flavonoid glycoside phytochemical compound, has a remarkable antiobesity effect. However, its therapeutic potential is hindered by its poor water solubility and low oral bioavailability. In this study, rutin was loaded into liposomes (LR) through the self-assembly of lecithin and cholesterol. It was discovered that liposomes improved the water solubility and cellular uptake of rutin in adipocytes. These rutin-loaded liposomes were then incorporated into a microneedle patch (MP) system formed by polyvinylpyrrolidone and poly(vinyl alcohol), and the MP-LR showed an increased release percentage in the adipose tissue microenvironment of pH 6.5 and achieved local delivery of rutin into adipocytes. Next, the therapeutic potentials of rutin, LR, and MP-LR were investigated in a high-fat diet (HFD)-induced obese mouse model. The MP-LR formulation decreased the weight of the HFD mice the most significantly. The antilipogenesis mechanisms of MP-LR are downregulating the lipid synthesis-related proteins (PPAR γ and C/EBP α) in adipocytes and promoting the expression of the beige adipogenesis-related proteins (UCP 1 and Cyt C). The MP systems further promote the local penetration of LR into the adipose tissue specifically, which again elevates their antiobesity effect. Overall, this study suggests that MP-delivered liposome-based formulation is a promising approach to enhance the antiobesity efficacy of antilipogenesis bioactive compounds.

Microneedles for advanced ocular drug delivery

In the field of ocular drug delivery, topical delivery remains the most common treatment option for managing anterior segment diseases, whileintraocular injectionsare the current gold standard treatment option for treating posterior segment diseases. Nonetheless, topical eye drops are associated with low bioavailability (<5%), and theintravitreal administration procedure is highly invasive, yielding poor patient acceptability. In both cases, frequent administration is currently required. As a result, there is a clear unmet need for sustained drug delivery to the eye, particularly in a manner that can be localised. Microneedles, which are patches containing an array of micron-scale needles (<1 mm), have the potential to meet this need. These platforms can enable localised drug delivery to the eye while enhancing penetration of drug molecules through key ocular barriers, thereby improving overall therapeutic outcomes. Moreover, the minimally invasive manner in which microneedles are applied could provide significant advantages over traditional intravitreal injections regarding patient acceptability. Considering the benefitsofthis novel ocular delivery system, this review provides an in-depth overviewofthe microneedle systems for ocular drug delivery, including the types of microneedles used and therapeutics delivered. Notably, we outline and discuss the current challenges associated with the clinical translation of these platforms and offer opinions on factors which should be considered to improve such transition from lab to clinic.

Microneedles and Their Application in Transdermal Delivery of Antihypertensive Drugs-A Review

One of the most cutting-edge, effective, and least invasive pharmaceutical innovations is the utilization of microneedles (MNs) for drug delivery, patient monitoring, diagnostics, medicine or vaccine delivery, and other medical procedures (e.g., intradermal vaccination, allergy testing, dermatology, and blood sampling). The MN-based system offers many advantages, such as minimal cost, high medical effectiveness, comparatively good safety, and painless drug application. Drug delivery through MNs can possibly be viewed as a viable instrument for various macromolecules (e.g., proteins, peptides, and nucleic acids) that are not efficiently administered through traditional approaches. This review article provides an overview of MN-based research in the transdermal delivery of hypertensive drugs. The critical attributes of microneedles are discussed, including the mechanism of drug release, pharmacokinetics, fabrication techniques, therapeutic applications, and upcoming challenges. Furthermore, the therapeutic perspective and improved bioavailability of hypertensive drugs that are poorly aqueous-soluble are also discussed. This focused review provides an overview of reported studies and the recent progress of MN-based delivery of hypertensive drugs, paving the way for future pharmaceutical uses. As MN-based drug administration bypasses first-pass metabolism and the high variability in drug plasma levels, it has grown significantly more important for systemic therapy. In conclusion, MN-based drug delivery of hypertensive drugs for increasing bioavailability and patient compliance could support a new trend of hypertensive drug delivery and provide an alternative option, overcoming the restrictions of the current dosage forms.

Transdermal Delivery of Glimepiride: A Novel Approach Using Nanomicelle-Embedded Microneedles

Glimepiride (GM) is a hydrophobic drug that dissolves slowly and yields inconsistent clinical responses after oral administration. Transdermal drug delivery (TDD) is an appropriate alternative to oral administration. Microneedles (MNs) offer a promising delivery system that penetrates the skin, while polymeric micelles can enhance the solubility; hence, the combination of both results in high drug bioavailability. This study aims to improve glimepiride's solubility, dissolution rate, and bioavailability by incorporating nanomicelles into MNs for TDD. The nanomicelles formulated with 10% Soluplus® (SP) and 40% GM had a mean particle size of 82.6 ± 0.54, PDI of 0.1 ± 0.01, -16.2 ± 0.18 zeta potential, and achieved a 250-fold increase in solubility. The fabricated pyramid shaped GM-dissolving MNs were thermally stable and had no formulation incompatibility, as confirmed by thermal and FTIR analysis. The in vitro dissolution profile revealed that the GM release from nanomicelles and nanomicelle-loaded DMN was concentration-independent following non-Fickian transport mechanism. Improved pharmacokinetic parameters were obtained with dose of 240 µg as compared to 1 mg of GM oral tablet, in healthy human volunteers. The observed Cmax, Tmax and MRT were 1.56 μg/mL ± 0.06, 4 h, and 40.04 h ± 3.37, respectively. The safety profile assessment indicated that microneedles are safe with no adverse effects on skin or health. This study provides an alternative delivery system for the administration of glimepiride, resulting in improved bioavailability, enhanced patient compliance, and reduced dosing frequency.

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 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.

Enhanced Skin Permeation and Controlled Release of β-Sitosterol Using Cubosomes Encrusted with Dissolving Microneedles for the Management of Alopecia

The use of synthetic medication for treating alopecia is restricted because of systemic exposure and related negative effects. Beta-sitosterol (β-ST), a natural chemical, has lately been studied for its potential to promote hair development. The cubosomes with dissolving microneedles (CUBs-MN_D) created in this study may be a useful starting point for the creation of a sophisticated dermal delivery system for β-ST. Cubosomes (CUBs) were prepared by the emulsification method, using glyceryl monooleate (GMO) as a lipid polymer. CUBs were loaded with dissolving microneedles (MN_D) fabricated with HA and a PVP-K90 matrix. An ex vivo skin permeation study and an in vivo hair growth efficacy test of β-ST were performed with both CUB and CUB-MN_D. The average particle size of the CUBs was determined to be 173.67 ± 0.52 nm, with a low polydispersity index (0.3) and a high zeta potential value that prevents the aggregate formation of dispersed particles. When compared to CUBs alone, CUBs-MN_D displayed higher permeating levels of β-ST at all-time points. In the animals from the CUB-MN_D group, significant hair development was observed. According to the results of the current investigation, CUBs that integrate dissolving microneedles of β-ST are superior in terms of transdermal skin penetration and activity for the treatment of alopecia.

Glucose-Responsive Microparticle-Loaded Dissolving Microneedles for Selective Delivery of Metformin: A Proof-of-Concept Study

Diabetes mellitus (DM) is a metabolic disorder that is one of the most common health problems in the world, primarily type 2 DM (T2DM). Metformin (MTF), as the first-line treatment of DMT2, is effective in lowering glucose levels, but its oral administration causes problems, including gastrointestinal side effects, low bioavailability, and the risk of hypoglycemia. In this study, we formulated MTF into microparticles incorporating a glucose-responsive polymer (MP-MTF-GR), which could potentially increase the bioavailability and extend and control the release of MTF according to glucose levels. This system was delivered by dissolving microneedles (MP-MTF-GR-DMN), applied through the skin, thereby preventing gastrointestinal side effects of orally administered MTF. MP-MTF-GR was formulated using various concentrations of gelatin as a polymer combined with phenylboronic acid (PBA) as a glucose-responsive material. MP-MTF-GR was encapsulated in DMN using polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) as DMN polymers. The physicochemical evaluation of MP-MTF-GR showed that MTF could be completely entrapped in MP with the percentage of MTF trapped increasing with increasing gelatin concentration without changing the chemical structure of MTF and producing stable MP. In addition, the results of the physicochemical evaluation of MP-MTF-GR-DMN showed that DMN had adequate mechanical strength properties and penetration ability and was stable to environmental changes. The results of the in vitro release and ex vivo permeation study on media with various concentrations of glucose showed that the release and permeation of MTF from the formula increased with increasing glucose levels in the media. The MP-MTF-GR-DMN formula successfully delivered MTF through the skin at 11.30 ± 0.29, 23.31 ± 1.64, 36.12 ± 3.77, and 53.09 ± 3.01 μg from PBS, PBS + glucose 1%, PBS + glucose 2%, and PBS + glucose 4%, respectively, at 24 h, which indicates glucose-responsive permeation and release behavior. The formula developed was also proven to be nontoxic based on hemolysis tests. Importantly, the in vivo study on the rat model showed that this combination approach could provide a better glucose reduction compared to other routes, reducing the blood glucose level to normal levels after 3 h and maintaining this level for 8 h. Furthermore, this approach did not change the skin moisture of the rats. This MP-MTF-GR-DMN is a promising alternative to MTF delivery to overcome MTF problems and increase the effectiveness of T2DM therapy.

A transfersomes hydrogel patch for cutaneous delivery of propranolol hydrochloride: formulation, in vitro, ex vivo and in vivo studies

OBJECTIVE

In this work, a propranolol hydrochloride (PRH) transfersomes loaded cutaneous hydrogel patch was developed for topical drug delivery in the affected area of infantile haemangioma.

METHODS

Sodium cholate was used as the edge activator to prepare the transfersomes. Based on the central composite design, transfersomes hydrogel patch formulation was optimised with 48 h cumulative penetration and time lag as response values. Particle sizes and morphology of the prepared transfersomes were assessed. They were loaded in a cutaneous hydrogel patch, after which their skin permeation abilities were evaluated, and histopathological effects were investigated using guinea pigs. Moreover, in vivo pharmacokinetics studies were performed in rats.

RESULTS

The transfersomes system had a encapsulation efficiency of 81.84 ± 0.53%, particle size of 186.8 ± 3.38 nm, polydispersity index of 0.186 ± 0.002, and a zeta potential of -28.6 ± 2.39 mV. Transmission electron microscopy images revealed sphericity of the particles. The ex vivo drug's penetration of the optimised transfersomes hydrogel patch was 111.05 ± 11.97 μg/cm² through rat skin within 48 h. Assessment of skin tissue did not reveal any histopathological alterations in epidermal and dermal cells. Pharmacokinetic studies showed that skin C_max (68.22 μg/cm²) and AUC_0-24 (1007.33 μg/cm² × h) for PRH transfersomes hydrogel patch were significantly higher than those of commercially available oral dosage form and hydrogel patch without transfersomes. These findings imply that the transfersomes hydrogel patch can prolong drug accumulation in the affected skin area, and reduce systemic drug distribution via the blood stream.

CONCLUSIONS

The hydrogel patch-loaded PRH transfersomes is a potentially useful drug formulation for infantile haemangioma.

Mechanistic modeling-guided optimization of microneedle-based skin patch for rapid transdermal delivery of naloxone for opioid overdose treatment

Naloxone, an FDA-approved opioid inhibitor, used to reverse opioid overdose complications has up till date faced challenges associated with its delivery. Limitations include the use of invasive delivery forms and the need for frequent redosing due to its short half-life. The goal of the current study was to design a transdermal rapidly dissolving polymeric microneedle (MN) patch with delivery and pharmacokinetic properties comparable to that seen with the commercially available NAL products, eliminating their delivery limitations. Patches of varying dimensions (500 µm; 100 array,800 µm; 100array, and 600 µm; 225 array) were fabricated to evaluate the effect of increasing MN length, and density (no. of needles/unit area) on drug release. Drug dose in each of these patches was 17.89 ± 0.23 mg, 17.2 ± 0.77 mg, and 17.8 ± 1.01 mg, respectively. Furthermore, the insertion efficiency of each of the MN patches was 94 ± 4.8%, 90.6 ± 1.69%, and 96 ± 1.29%, respectively. Compared to passive permeation, a reduced lag time of about 5-15 min was observed with a significant drug flux of 15.09 ± 7.68 g[Formula: see text]/cm²/h seen in the first 1 h (p < 0.05) with the array of 100 needles (500 µm long). Over 24 h, a four and ten-fold increase in permeation was seen with the longer length and larger density MN patch, respectively, when compared to the 500 µm (100 array) patch. Model simulations and analyses revealed the significance of needle base diameter and needle count in improving systemic pharmacokinetics of NAL.

Transdermal delivery of inflammatory factors regulated drugs for rheumatoid arthritis

Rheumatoid arthritis is a chronic autoimmune disease, with the features of recurrent chronic inflammation of synovial tissue, destruction of cartilage, and bone erosion, which further affects joints tissue, organs, and systems, and eventually leads to irreversible joint deformities and body dysfunction. Therapeutic drugs for rheumatoid arthritis mainly reduce inflammation through regulating inflammatory factors. Transdermal administration is gradually being applied to the treatment of rheumatoid arthritis, which can allow the drug to overcome the skin stratum corneum barrier, reduce gastrointestinal side effects, and avoid the first-pass effect, thus improving bioavailability and relieving inflammation. This paper reviewed the latest research progress of transdermal drug delivery in the treatment of rheumatoid arthritis, and discussed in detail the dosage forms such as gel (microemulsion gel, nanoemulsion gel, nanomicelle gel, sanaplastic nano-vesiclegel, ethosomal gel, transfersomal gel, nanoparticles gel), patch, drug microneedles, nanostructured lipid carrier, transfersomes, lyotropic liquid crystal, and drug loaded electrospinning nanofibers, which provide inspiration for the rich dosage forms of transdermal drug delivery systems for rheumatoid arthritis.

Recent Advances of Hyaluronan for Skin Delivery: From Structure to Fabrication Strategies and Applications

Hyaluronan (HA) plays a fundamental role in maintaining the homeostasis on skin health. Furthermore, the effect of HA in skin inflammatory diseases is worth studying in the next future. HA and its conjugates change the solubility of active pharmaceutical ingredients, improve emulsion properties, prolong stability, reduce immunogenicity, and provide targeting. HA penetrates to deeper layers of the skin via several mechanisms, which depend on the macromolecular structure and composition of the formulation. The cellular and molecular mechanisms involved in epidermal dysfunction and skin aging are not well understood. Nevertheless, HA is known to selectively activate CD44-mediated keratinocyte signaling that regulates its proliferation, migration, and differentiation. The molecular size of HA is critical for molecular mechanisms and interactions with receptors. High molecular weight HA is used in emulsions and low molecular weight is used to form nanostructured lipid carriers, polymeric micelles, bioconjugates, and nanoparticles. In the fabrication of microneedles, HA is combined with other polymers to enhance mechanical properties for piercing the skin. Hence, this review aims to provide an overview of the current state of the art and last reported ways of processing, and applications in skin drug delivery, which will advocate for their broadened use in the future.

Dissolving microneedles for long-term storage and transdermal delivery of extracellular vesicles

Extracellular vesicles (EVs) have shown great potential in disease diagnosis and treatment; however, their clinical applications remain challenging due to their unsatisfactory long-term stability and the lack of effective delivery strategies. In this study, we prepared human adipose stem cell-derived EV (hASC-EV)-loaded hyaluronic acid dissolving microneedles (EV@MN) to investigate the feasibility of EVs for their clinical applications. The biological activities of the EVs in this formulation were maintained for more than six months under mild storage conditions, especially at temperatures lower than 4 °C. Moreover, the EV@MN enabled precise and convenient intradermal delivery for sustained release of EVs in the dermis layer. Therefore, EV@MN significantly improved the biological functions of hASC-EVs on dermal fibroblasts by promoting syntheses of proteins for the extracellular matrix such as collagen and elastin, enhancing fibroblast proliferation, and regulating the phenotype of fibroblast, compared with other administration methods. This research revealed a possible and feasible formulation for the clinical application of EVs.

Polysaccharide-Based Transdermal Drug Delivery

Materials derived from natural plants and animals have great potential for transdermal drug delivery. Polysaccharides are widely derived from marine, herbal, and microbial sources. Compared with synthetic polymers, polysaccharides have the advantages of non-toxicity and biodegradability, ease of modification, biocompatibility, targeting, and antibacterial properties. Currently, polysaccharide-based transdermal drug delivery vehicles, such as hydrogel, film, microneedle (MN), and tissue scaffolds are being developed. The addition of polysaccharides allows these vehicles to exhibit better-swelling properties, mechanical strength, tensile strength, etc. Due to the stratum corneum’s resistance, the transdermal drug delivery system cannot deliver drugs as efficiently as desired. The charge and hydration of polysaccharides allow them to react with the skin and promote drug penetration. In addition, polysaccharide-based nanotechnology enhances drug utilization efficiency. Various diseases are currently treated by polysaccharide-based transdermal drug delivery devices and exhibit promising futures. The most current knowledge on these excellent materials will be thoroughly discussed by reviewing polysaccharide-based transdermal drug delivery strategies.

Fabricating High-Resolution and High-Dimensional Microneedle Mold through the Resolution Improvement of Stereolithography 3D Printing

Microneedles are transdermal drug delivery tools that can be fabricated simply, economically, and rapidly using SLA 3D printing. However, SLA 3D printing has a limitation in that the resolution is slightly lowered when the microneedle is precisely printed. To solve this issue, we optimized the SLA 3D printing conditions such as printing angle, needle height, aspect ratio, and spacing between the microneedles for high-resolution microneedle fabrication. The sharpest microneedle tip was obtained when the printing angle was adjusted to 60° in both the x and y axes. The aspect ratio and the spacing between the microneedles did not affect the output of the sharp tip. Under optimal conditions, the microneedles with 1180 ± 20 µm height, 490 ± 20 µm base, and 30.2 ± 3.4 µm tip diameter were obtained. The dissolving microneedle patch, prepared using the 3D printed microneedle as a mold, penetrated the porcine skin ex vivo. When the printing angle was 60° in the x and y axes, the area of the single stacking layer, including the microneedle tip, increased, and thus the sharp tip could be printed. A high-dimensional, side-notched arrowhead (SNA) microneedle was fabricated by applying the SLA 3D printing condition. Moreover, a letter-type microneedle patch was fabricated using the customized characteristics of 3D printing. Consequently, high-resolution and high-dimensional microneedles were successfully fabricated by adjusting the printing angle using a general SLA 3D printer, and this technology will be applied to the manufacture of drug delivery tools and various microstructures.