Current status and future potential of transdermal drug delivery

Impact of various electromagnetic fields on the transdermal permeability of naproxen and the effect of active compound exposure on magnetic field properties

Transdermal drug delivery systems present a promising alternative to oral administration, though improving skin permeability of active pharmaceutical ingredients (APIs) remains challenging. This study examines how various electromagnetic fields (EMFs) affect the transdermal permeability of naproxen (NAP) and its physicochemical properties. Using pigskin as a model, NAP permeability was tested under oscillating, pulsed, static, and rotating magnetic fields (RMF), compared to a control group without EMF exposure. The results show significant differences in NAP permeability depending on EMF type, with RMF at 50 Hz yielding the highest cumulative permeation mass (CPM) of 1461.40 ± 256.15 µg/cm2, compared to 267.57 ± 41.74 µg/cm2 for the control. RMF 50 Hz also maximized steady-state flux (JSS) and permeability coefficient (KP), highlighting its potential for enhanced transdermal delivery. Conversely, static magnetic fields with negative polarization reduced permeation, showing a complex interaction between magnetic fields and skin permeability. The study also found that RMF treatments lowered NAP skin accumulation, improving permeation efficiency. Physicochemical analyses (FTIR, XRD, solubility, and lipophilicity) revealed that while EMF exposure did not significantly change NAP's crystal structure, it did affect solubility and partition coefficient. This research highlights the potential of optimizing EMF parameters to enhance transdermal drug delivery and provides insights into the physicochemical interactions between EMFs and active compounds. The findings suggest that rotating magnetic fields, particularly at 50 Hz, offer the most significant improvement in drug permeability, which could be beneficial for developing advanced transdermal delivery systems.

Hollow microneedles as a flexible dosing control solution for transdermal drug delivery

Microneedles, small needle-like structures typically less than 1000 μm in length, are effective tools for transporting substances across biological barriers via minimally invasive pathways. Various microelectromechanical system (MEMS) processes enable the production of different types of microneedles, including solid, coated, dissolving, hydrogel, and hollow microneedles, each tailored to specific drug and fluid delivery mechanisms. Among these, hollow microneedles stand out for their ability to offer flexible dosage control adaptable to varying drug formulations, making them particularly promising for transdermal drug delivery systems. This review examines the fabrication processes of hollow microneedles, highlights the advantages of their hollow structure for medical applications, and discusses the key factors influencing their performance. Finally, it proposes directions for advancing these technologies in both industrial and research settings.

Iontophoresis and electroporation-assisted microneedles: advancements and therapeutic potentials in transdermal drug delivery

Transdermal drug delivery (TDD) using electrically assisted microneedle (MN) systems has emerged as a promising alternative to traditional drug administration routes. This review explores recent advancements in this technology across various therapeutic applications. Integrating iontophoresis (IP) and electroporation (EP) with MN technology has shown significant potential in improving treatment outcomes for various conditions. Studies demonstrate their effectiveness in enhancing vaccine and DNA delivery, improving diabetes management, and increasing efficacy in dermatological applications. The technology has also exhibited promise in delivering nonsteroidal anti-inflammatory drugs (NSAIDs), treating multiple sclerosis, and advancing obesity and cancer therapy. These systems offer improved drug permeation, targeted delivery, and enhanced therapeutic effects. While challenges remain, including safety concerns and technological limitations, ongoing research focuses on optimizing these systems for broader clinical applications. The future of electrically assisted MN technologies in TDD appears promising, with potential advancements in personalized medicine, smart monitoring systems, and expanded therapeutic applications.

Mesoporous silica nanoparticles-embedded hydrogel: A potential approach for transdermal delivery of carvedilol to pediatric population

Age-appropriate drug formulations, especially for children, are often limited. A beta-blocker, Carvedilol (CRV) has recently been reported as an off-label option for the management of cardiovascular disorders in pediatric patients. CRV exhibits a pH-dependent solubility and undergoes extensive hepatic metabolism, resulting in low oral bioavailability. Mesoporous silica nanoparticles (MSNs) of two types (MCM-41 and SBA-15) were loaded with CRV at three saturation levels to improve its dissolution rate. At high saturation level, CRV-loaded SBA-15 showed superior dissolution with a dissolution efficiency of 72.42 % and significant dissimilarity (f1 = 211.80, f2 = 16.89) compared to pure CRV, demonstrating enhanced solubility and dissolution rate due to its amorphous transformation and large pore diameter. Thermal and diffractometry analysis revealed the adsorption of CRV to MSNs in an amorphous state. CRV-loaded SBA-15 was incorporated into gel bases, and the amount of CRV released from triple-layer loaded gels was found to be higher than monolayer-loaded formulations. The ex vivo skin permeation study revealed a significant enhancement of drug release and permeation for CRV-loaded SBA-15 gel formulations (714.49 ± 38.49 µg/cm2) after 24 h, compared to the control (236.19 ± 18.93 µg/cm2), with flux increased by 62 %. Improving pediatric compliance by providing a convenient, non-invasive, and palatable drug delivery option that minimizes dosing errors and enhances treatment adherence. Our study suggests CRV-loaded SBA-15 transdermal gel as a pediatric-friendly alternative to oral delivery, addressing bitter taste, bypassing hepatic metabolism, and improving bioavailability while reducing side effects.

A Bibliometric Analysis of Microneedle-Mediated Drug Delivery: Trends, Hotspots, and Future Directions

Purpose

Microneedles can physically penetrate the stratum corneum, creating micropores on the skin, and allowing for drug delivery through direct diffusion, injection, or other methods. As a novel drug delivery method, it possesses significant application potential. This study uses bibliometric analysis to explore the research hotspots and development trends of microneedle-mediated drug delivery.

Methods

Relevant research articles on microneedle-mediated drug delivery published between 1998 and 2024 in the Web of Science Core Collection (WoSCC) database were retrieved. Data analysis and visualization were performed using VOSviewer, CiteSpace, Scimago Graphica, and Pajek, enabling the prediction of research trends in microneedle-mediated drug delivery.

Results

In general, research on microneedle-mediated drug delivery has shown a continuous increase. China and the United States are the leading countries in this field of study. Notably, Ryan F. Donnelly (n=224) is the most prominent contributor to this field. The current core research directions include: disease treatment, enhancement of transdermal absorption performance of microneedles, vaccine delivery, and new materials and technologies for microneedle manufacturing.

Conclusion

Microneedle-mediated drug delivery, as a novel technology and method, holds significant research value and application potential. However, further strengthening of international collaboration and the clinical translation of research findings are needed.

Are lateral lipid-phase diffusion coefficients pertinent to dermal absorption?

The skin's outer barrier layer, the stratum corneum (SC), is comprised of keratin-rich corneocytes, connected by proteinaceous corneodesmosomes and separated by nonpolar, lamellar lipids. The lipids are inherently anisotropic due to their lamellar organization. There is growing acceptance that this structural anisotropy carries over into transport properties including diffusive mass transport, which is consequently characterized by two diffusion coefficients, D∥lip for lateral diffusion along the lipid lamellae and D⊥lip for transverse diffusion across them. Many microscopic models of SC transport have focused on D∥lip, as it is easier to measure and intuitively important if one considers the intervening corneocytes to be impermeable "bricks." However, the latter concept crumbles under close observation, and the weight of evidence shows that the corneocyte phase of the SC is considerably more permeable to most solutes than are the intercellular lipids. Given this finding and a plausible organization of the SC lipids at corneocyte boundaries, the ratio determines the balance of transcellular versus intercellular diffusion. Based on a detailed microscopic analysis of solute diffusion within the SC, we conclude that passive transdermal permeation is affected to only a modest degree (within a factor of ∼2) by the value of D∥lip over the full range of values typically encountered. This statement applies to all but highly lipophilic solutes, i.e., to solutes with log10Koct/w≲5. The transverse diffusivity D⊥lip is a much more quantitatively influential parameter affecting macroscopically observable diffusion in the transdermal direction. Consequently, D⊥lip is the diffusivity that should be used in nondimensionalizing SC diffusion models to reduce computational burden. Furthermore, the analysis lends additional support to previous findings from several groups that transcellular diffusion is the dominant mechanism for passive transdermal permeation for all but the most lipophilic and the most hydrophilic solutes.

Bioinspired Suction-Driven Strategies with Nanoscale Skin-Controllable Adhesive Architectures for Efficient Liquid Formulated Transdermal Patches

For highly efficient and precise drug release, transdermal drug delivery systems (TDDS) have recently evolved through the combination of intelligent material-based structures with various active components. These strategies are an effort to overcome the significant difficulties in delivering large molecule drugs and nanomaterials due to the physical barrier of the skin, especially the stratum corneum, in traditional TDDS. Interestingly, multiscale suction-driven architectures (SDAs) inspired by bioinspired suction adhesion mechanisms have provided innovative solutions to these challenges. These architectures employ negative pressure to enhance nanoscale skin-controllable skin adhesion, temporarily bypass the skin barrier, and facilitate deep penetration of therapeutic agents, thereby, achieving the goals of increasing drug delivery efficiency and maximizing user convenience as a minimal invasive, needle-free platform. This review provides a comprehensive overview of suction-driven transdermal patches and emphasizes their integration with multifunctional materials to achieve stable adhesion and controlled drug release. Next, we present cost-effective and user-friendly suction-driven drug delivery patch devices through optimization of cupping structures without the incorporation of additional devices. Furthermore, we present cost-effective and user-friendly transdermal drug delivery patch devices that optimize multiscale cupping architectures without the need for additional devices. Potential of bioinspired SDAs in localized and systemic drug delivery through challenging and complex skin, as well as future perspectives, are discussed, along with innovative directions for more efficient and patient-centric transdermal drug delivery solutions.

WITHDRAWN: Impact of various electromagnetic fields on the transdermal permeability of naproxen and the effect of active compound exposure on magnetic field properties

This article has been withdrawn: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies-and-standards/article-withdrawal). This article has been withdrawn at the request of the editor and publisher. The publisher regrets that an error occurred which led to the premature publication of this paper. This error bears no reflection on the article or its authors. The publisher apologizes to the authors and the readers for this unfortunate error.

Nanotherapy targeting anti-aging skin cells: harnessing ursolic acid from Ocimum sanctum Linn for precision skin rejuvenation - a molecular perspective

The necessity of this work lies in the innovative application of nanotherapy to target anti-ageing skin cells, utilising ursolic acid from Ocimum sanctum Linn for precise and effective skin rejuvenation at a molecular level. Ursolic acid (UA), a pentacyclic triterpenoid compound, found in abundance in the plant O. sanctum Linn, has long been recognised for its potential anti-inflammatory, antioxidant, and anti-ageing properties. Despite its promising benefits, the direct application of UA in skincare has been limited, primarily due to its low aqueous solubility and poor skin penetration. This study explores a groundbreaking molecular approach, employing nanotechnology to enhance the delivery of UA, targeting skin cells for effective anti-ageing treatment. Through a comprehensive investigation, UA was encapsulated into biocompatible nanocarriers, ensuring increased stability, improved dermal penetration, and sustained release of the compound at the targeted site. By harnessing the specificity and efficiency of nanodelivery systems, the study achieved significant improvement in the absorption of UA in the deeper layers of the skin. This targeted intervention at the cellular and molecular level paved the way for maximising the potential of UA as an anti-ageing agent. In conclusion, the nanotherapeutic delivery of UA from O. sanctum Linn offers a paradigm shift in skincare, bringing forth a promising molecular strategy to combat skin ageing. With further advancements, this approach has the potential to revolutionise anti-ageing treatments, integrating traditional botanical wisdom with cutting-edge nanotechnology.

Overview of Therapeutic Ultrasound Applications and Safety Considerations: 2024 Update

A 2012 review of therapeutic ultrasound was published to educate researchers and physicians on potential applications and concerns for unintended bioeffects (doi: 10.7863/jum.2012.31.4.623). This review serves as an update to the parent article, highlighting advances in therapeutic ultrasound over the past 12 years. In addition to general mechanisms for bioeffects produced by therapeutic ultrasound, current applications, and the pre-clinical and clinical stages are outlined. An overview is provided for image guidance methods to monitor and assess treatment progress. Finally, other topics relevant for the translation of therapeutic ultrasound are discussed, including computational modeling, tissue-mimicking phantoms, and quality assurance protocols.

Skin penetration enhancers: Mechanistic understanding and their selection for formulation and design

The skin functions as a formidable barrier, particularly the stratum corneum, effectively restricting the penetration of most substances, including therapeutic agents. To circumvent this barrier, skin penetration enhancers (SPEs) are frequently employed to transiently increase skin permeability, facilitating drug absorption without causing irritation or damage. Despite advancements in dermal formulation development, a deeper understanding of the fundamental science underpinning drug delivery via SPEs remains essential. This review delivers a critical update on conventional SPEs, exploring their mechanisms in promoting drug permeation across the skin. In addition to offering an overview of percutaneous drug delivery, we examine the prevailing theories on how SPEs enhance drug transport. Furthermore, we address the intricate interplay between SPEs, drugs and the skin, providing valuable insights into how the molecular properties and permeation behaviours of SPEs influence their efficacy. This comprehensive review aims to support the ongoing development of optimised drug delivery systems for dermal applications by elucidating the complexities and challenges involved in using SPEs effectively.

Mathematical modelling of hollow microneedle-mediated transdermal drug delivery

Hollow microneedles represent a promising approach for overcoming the protective barrier of the stratum corneum, facilitating direct drug infusion into viable skin tissue and thereby enhancing the efficacy of transdermal delivery. However, delivery outcomes across different skin layers and into the systemic circulation can vary substantially due to the diverse properties of drug delivery systems, clinical settings, and environmental factors. The optimal strategies for enhancing the efficiency of hollow microneedle-mediated transdermal drug delivery remain to be elucidated. This study employs mathematical modelling and a reconstructed skin model with realistic anatomical structures to investigate drug transport and accumulation across different skin layers and into the bloodstream under different delivery conditions. The modelling results reveal the crucial role of interstitial fluid flow in determining drug transport in this transdermal delivery. Delivery outcomes of each skin layer and blood exhibit distinct responses to changes in delivery conditions. Specifically, increasing the vascular permeability or nanocarrier diffusivity raises drug concentration in the blood or reticular dermis, respectively, while leading to reductions in other skin layers. The use of microneedles with narrower infusion channels can only enhance drug availability in the viable epidermis. Optimisation requires a tailored approach to several parameters depending on the target skin layer, including drug release rate, infusion rate, infusion duration, and microneedle length. Environmental factors that promote trans-epidermal water loss can increase drug concentration in the viable epidermis but have a limited impact on deeper skin tissues. The findings support the selection or customisation of hollow microneedles and nanocarriers to address specific therapeutic needs, such as targeting specific skin layers or systemic circulation, while minimising the risk of side effects from high drug concentrations in normal tissues. This study provides guidance for optimising transdermal drug delivery systems.

Formulation development and evaluation, in silico PBPK modeling and in vivo pharmacodynamic studies of clozapine matrix type transdermal patches

Clozapine is a potent serotonin receptor antagonist and commonly used for the treatment of Schizophrenia. The study aimed to develop and optimize the transdermal matrix patch of clozapine. A 3-level, 3-factor Central Composite Design was applied to examine and validate the impact of various formulation variables, Eudragit, PEG, and oleic acid on in vitro drug release, flux, and tensile strength (TS). Different formulation characteristics were studied in terms of physico-chemical characterization, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), drug release performance, and in vitro permeability. The numerical and graphical optimization was based on the desirability function and the optimized formulation obtained from the polynomial equation was further validated and evaluated for the targeted critical attributes. The optimized patch was further evaluated for skin irritation, in vivo pharmacodynamics, in silico prediction, and simulation using the GastroPlus TCAT® model and stability. The experimental results of the optimized formulation, such as tensile strength 1.220 kg/cm2, flux 147.376 μg/cm2/h and Q24 94.874%, showed similarity with the values predicted by numerical and graphical optimization. In vivo Neuro-pharmacological studies showed that the results were comparable to the standard. The Cmax, Tmax, AUCt, and AUCinf were predicted as 38.396 ng/mL, 28.960 h, 1625.500 ng-h/mL, and 1175.700 ng-h/mL for a 50 mg patch. No skin irritation was found for the optimized transdermal patch as per the Draize score method. The shelf life of the optimized formulation was 30.41 months under accelerated conditions. The study showed that the matrix-type transdermal patch of clozapine can be used for the management of schizophrenia in terms of improved patient compliance.

Chitooligosaccharides promote diabetic wound healing by mediating fibroblast proliferation and migration

Diabetic wounds are notoriously difficult to heal due to impaired cell repair mechanisms, reduced angiogenesis, and a heightened risk of infection. Fibroblasts play a vital role in wound healing by producing extracellular matrix (ECM) components and various growth factors, but their function is inhibited in diabetic wounds. Chitooligosaccharides (COS), intermediate products of chitosan degradation, have shown efficacy in promoting tissue repair, yet their role in diabetic wound healing remains underexplored. In a mouse model of diabetic wounds, COS treatment demonstrated substantial bioactivity in accelerating wound healing by enhancing fibroblast proliferation and migration. Additionally, COS increased collagen III deposition and angiogenesis at the wound sites. The COS also mitigated inflammatory responses by controlling leukocyte infiltration and bacterial infection. Mechanistically, COS regulated fibroblast activity via the PI3K/Akt signaling pathway, providing a novel bioactive material for chronic wound healing.

Elevating Therapeutic Penetration: Innovations in Drug Delivery for Enhanced Permeation and Skin Cancer Management

Skin cancer stands as a challenging global health concern, necessitating innovative approaches to cure deficiencies within traditional therapeutic modalities. While conventional drug delivery methods through injection or oral administration have long prevailed, the emergence of topical drug administration presents a compelling alternative. The skin, aside from offering a swift and painless procedure, serves as a reservoir, maintaining drug efficacy over extended durations. This comprehensive review seeks to shed light on the potential of nanotechnology as a promising avenue for efficacious cancer treatment, with a particular emphasis on skin cancer. Additionally, it underscores the transdermal approach as a viable strategy for addressing various types of cancer. This work also explores into the delivery of peptides and proteins along with in-depth explanations of different delivery systems currently under investigation for localized skin cancer treatment. Furthermore, the review discusses the formidable challenges that must be surmounted before these innovations can find their way into clinical practice, offering a roadmap for future research and therapeutic development.

Evaluation of Papain-Urea for Enzymatic Debridement of Coagulation Zones Following Ablative Fractional Laser Treatment

BACKGROUND

Ablative fractional CO2 laser (10,600 nm) treatment creates an array of microscopic treatment zones composed of an ablation zone (AZ) surrounded by a denatured coagulation zone (CZ). The CZ is believed to play a functional role in skin tightening, posttreatment inflammation, and laser-assisted drug delivery. This study investigates the viability of enzymatic post-processing to remove the CZ without affecting the surrounding tissue.

METHODS

Ex vivo skin samples were treated with either control, papain, urea, or papain-urea solutions before being covered with occlusive dressing and incubated at 37°C for 1 h. Tissue viability as well as AZ and CZ geometries were assessed histologically.

RESULTS

Treatment with all three experimental solutions resulted in a decrease in CZ. The largest average reduction in CZ area was observed in the papain-urea group (44%, p < 0.001), followed by the papain (14%, p < 0.001) and urea (11%, p < 0.001) only groups. Only the papain-urea group showed a significant increase in AZ (14%) and changes in lesion geometry.

CONCLUSION

This exploratory study of enzymatic post-processing with papain-urea highlighted the potential of selectively removing the CZ after treatment with ablative fractional laser therapy. If results can be translated to in vivo studies, these findings could expand the use of high-fluence CO2 laser therapy with functional implications for lowering posttreatment recovery time, providing clinicians more control over skin tightening, and enabling a broader range of laser-assisted drug delivery.

Smart Ultrasound-responsive Polymers for Drug Delivery: An Overview on Advanced Stimuli-sensitive Materials and Techniques

In recent years, a notable advancement has occurred in the domain of drug delivery systems via the integration of intelligent polymers that respond to ultrasound. The implementation of this groundbreaking methodology has significantly revolutionised the controlled and precise delivery of therapeutic interventions. An in-depth investigation is conducted into the most recent developments in ultrasonic stimulus-responsive materials and techniques for the purpose of accomplishing precise medication administration. The investigation begins with an exhaustive synopsis of the foundational principles underlying drug delivery systems that react to ultrasonic stimuli, focusing specifically on the complex interplay between polymers and ultrasound waves. Significant attention is devoted to the development of polymers that demonstrate tailored responsiveness to ultrasound, thereby exemplifying their versatility in generating controlled drug release patterns. Numerous classifications of intelligent polymers are examined in the discussion, including those that react to variations in temperature, pH, and enzymes. When coupled with ultrasonic stimuli, these polymers offer a sophisticated framework for the precise manipulation of drug release in terms of both temporal and spatial dimensions. The present study aims to examine the synergistic effects of responsive polymers and ultrasound in overcoming biological barriers such as the blood-brain barrier and the gastrointestinal tract. By doing so, it seeks to shed light on the potential applications of these materials in intricate clinical scenarios. The issues and future prospects of intelligent ultrasound-responsive polymers in the context of drug delivery are critically analysed in this article. The objective of this study is to offer valuable perspectives on the challenges that must be overcome to enable the effective implementation of these technologies. The primary objective of this comprehensive review is to furnish researchers, clinicians, and pharmaceutical scientists with a wealth of information that will serve as a guide for forthcoming developments in the development and enhancement of intelligent drug delivery systems that employ ultrasound-responsive polymers to attain superior therapeutic outcomes.

Novel drug delivery systems for hirudin-based product development and clinical applications

Hirudin, a natural biological polypeptide macromolecule secreted by the salivary glands of medicinal leech, is a specific thrombin inhibitor with multiple favourable bioactivities, including anti-coagulation, anti-fibrotic, and anti-tumour. Despite several anticoagulants have been widely applied in clinic, hirudin shows advantages in reducing the incidence of bleeding side effects by virtue of its high specificity in binding to thrombin. As a result, hirudin has been tested in clinical practice to prevent and treat several complex diseases. However, the application of this polypeptide macromolecule is compromised by its low bioavailability and bioactivity due to poor serum stability and susceptibility to protease degradation in vivo. To overcome these drawbacks, several studies have proposed novel drug delivery systems (NDDSs) to prevent the degradation and increase the targeting efficiency of hirudin. This systematic review summarises the clinical research on hirudin, including its classification and bioactivities, and highlights the opportunities and challenges in the clinical use of hirudin. The NDDSs designed to enhance the bioavailability and bioactivity of hirudin are discussed to explore its application in the treatment of related diseases. This review may considerably contribute to the advancement of delivery science and technology, particularly in the context of polypeptide-based therapeutics.

Enhanced transdermal delivery of insulin by choline-based ionic liquids

Ionic liquids (ILs) show promises as chemical penetration enhancers (CPEs) for transdermal delivery of macromolecular drugs. However, their high viscosity and strong drug-IL affinity may limit drug diffusion and release from the drug-loaded IL (one-step strategy). Herein, a two-step strategy was used by applying choline-based ILs as pretreatment agents followed by insulin solution to improve penetration. Insulin remained stable in the ILs and are released slowly from the IL matrices. In vitro and in vivo studies showed that two-step treatment enhanced insulin penetration compared to one-step treatment, with choline citrate ([Ch][Ci]) and choline geranate ([Ch][Ge]) performing the best. In a diabetic rat model, two-step treatment with [Ch][Ge] reduced blood glucose levels to below 80% within 8 h, while one-step treatment only maintained for 12 h. Trans-epidermal water loss and molecular dynamics simulations suggested that variations in release rates and skin condition accounted for the differences between the two strategies. Physical characterization confirmed that ILs enhanced transdermal delivery of insulin by permeabilizing stratum corneum and opening tight junctions. Preliminary safety assessment indicated mild irritation by [Ch][Ge], whereas [Ch][Ci] showed good biocompatibility. It is concluded that ILs hold potential in enhancing transdermal delivery of insulin.

Iontophoresis-Integrated Smart Microneedle Delivery Platform for Efficient Transdermal Delivery and On-Demand Insulin Release

Transdermal insulin delivery in a painless, convenient, and on-demand way remains a long-standing challenge. A variety of smart microneedles (MNs) fabricated by glucose-responsive phenylboronic acid hydrogels have been previously developed to provide painless and autonomous insulin release in response to a glucose level change. However, like the majority of MNs, their transdermal delivery efficiency was still relatively low compared to that with subcutaneous injection. Herein, we report an iontophoresis (ITP)-integrated smart MNs delivery platform with enhanced transdermal delivery efficiency and delivery depth. Carbon nanotubes (CNTs) were induced in the boronate-containing hydrogel to develop a semi-interpenetrating network hydrogel with enhanced stiffness and conductivity. Remarkably, ITP not only facilitated efficient and deeper transdermal delivery of insulin via electroosmosis and electrophoresis but also well-maintained glucose responsiveness. This ITP-combined smart MNs delivery platform, which could provide on-demand insulin delivery in a painless, convenient, and safe way, is promising to achieve persistent glycemic control. Furthermore, transdermal delivery of payloads with a wide size range was achieved by this delivery platform and thus shed light on the development of an efficient transdermal delivery platform with deep skin penetration in a minimally invasive way.

Atopic dermatitis treatment: A comprehensive review of conventional and novel bioengineered approaches

Atopic dermatitis (AD) remains a challenging condition, with conventional treatments often leading to adverse effects and limited efficacy. This review explores the diverse landscape of AD treatments, encompassing conventional methods, novel topical and systemic therapies, and emerging bioengineered strategies. While conventional drug administration often requires high dosages or frequent administration, leading to adverse effects, targeted biologics have shown promise. Phototherapy and wet wrap therapy, while helpful, have limitations. Given these factors, the need for modern and effective therapeutic strategies for AD is pressing. Complementary or alternative therapies have garnered significant attention in recent years as a compelling treatment for AD. Among these, functionalized biomaterials and textiles with physicochemical, nanotechnology-based characteristics, or bioengineered features are some of the most common typical adjuvant therapies. The multifunctional-engineered biomaterials, as a new generation of biomedical materials, and stem cells, seem to hold tremendous promise for the treatment of dermatological diseases like AD. Biomaterials have seen great success, especially in various medical fields, due to their unique and adaptable characteristics. These materials, including collagen, PCL, and PLGA, offer unique advantages, such as biocompatibility, biodegradability, controlled drug release, and enhanced drug retention.

Synergistic Strategies of Biomolecular Transport Technologies in Transdermal Healthcare Systems

Transdermal healthcare systems have gained significant attention for their painless and convenient drug administration, as well as their ability to detect biomarkers promptly. However, the skin barrier limits the candidates of biomolecules that can be transported, and reliance on simple diffusion poses a bottleneck for personalized diagnosis and treatment. Consequently, recent advancements in transdermal transport technologies have evolved toward active methods based on external energy sources. Multiple combinations of these technologies have also shown promise for increasing therapeutic effectiveness and diagnostic accuracy as delivery efficiency is maximized. Furthermore, wearable healthcare platforms are being developed in diverse aspects for patient convenience, safety, and on-demand treatment. Herein, a comprehensive overview of active transdermal delivery technologies is provided, highlighting the combination-based diagnostics, therapeutics, and theragnostics, along with the latest trends in platform advancements. This offers insights into the potential applications of next-generation wearable transdermal medical devices for personalized autonomous healthcare.

Controlled Transdermal Delivery of Dexamethasone for Pain Management via Photochemically 3D-Printed Bioresorbable Microneedle Arrays

Microneedle array patches (MAPs) are extensively studied for transdermal drug delivery. Additive manufacturing enables precise control over MAP customization and rapid fabrication. However, the scope of 3D-printable, bioresorbable materials is limited. Dexamethasone (DXM) is widely used to manage inflammation and pain, but its application is limited by systemic side effects. Thus, it is crucial to achieve high local drug concentrations while maintaining low serum levels. Here, poly(propylene fumarate-co-propylene succinate) oligomers are fabricated into DXM-loaded, bioresorbable MAPs via continuous liquid interface production 3D printing. Thiol-ene click chemistry yields MAPs with tailorable mechanical and degradation properties. DXM-loaded MAPs exhibit controlled elution of drug in vitro. Transdermal application of DXM-loaded MAPs in a murine tibial fracture model leads to substantial relief of postoperative pain. Pharmacokinetic analysis shows that MAP administration is able to control pain at a significantly lower dose than intravenous administration. This work expands the material properties of 3D-printed poly(propylene fumarate-co-propylene succinate) copolyesters and their use in drug delivery applications.

Advancements in microneedle technology: current status and next-generation innovations

Microneedle technology is a pivotal component of third-generation transdermal drug delivery systems featuring tiny needles that create temporary microscopic channels in the stratum corneum which facilitate drug penetration in the dermis. This review offers a detailed examination of the current types of microneedles, including solid, coated, dissolving, hollow, and swelling microneedles, along with their preparation techniques as well as their benefits and challenges. Use of 3D printing technology is especially gaining significant attention due to its ability to achieve the high dimensional accuracy required for precise fabrication. Additionally, its customisability presents significant potential for exploring new designs and creating personalised microneedles products. Furthermore, this review explores next generation microneedles, especially stimuli-responsive microneedle, bioinspired microneedle and microneedles combined with other transdermal technology like sonophoresis, electroporation and iontophoresis. Regulatory aspects, characterisation techniques, safety considerations, and cost factors have also been addressed which are crucial for translation from lab to the market.

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.

A Self-Assembled Transdermal Nanomedicines Incorporating Pendant Disulfides for Non-Invasive, Synergistic Treatment of Melanoma

Transdermal drug delivery system (TDDS) offers lower systemic toxicity and good patient compliance, making it a promising treatment option for skin-related cancers. However, physiological barriers in the skin frequently impede the therapeutic efficiency of TDDS. To address this, a unique self-assembled TDDS that incorporates disulfide pendant groups (termed Sup-TDDS) is presented. It is formulated with dithiolane-containing lipoic acid (LA), photosensitizers Ce6, and chemotherapeutic agents trametinib. Pendant disulfide moieties on Sup-TDDS facilitate thiol-disulfide exchange reactions with exofacial thiols on cell surfaces, thus enhancing stratum corneum penetration. In contrast to intravenous injection, topical administration of Sup-TDDS can penetrate deeper into the skin (> 500 µm) and promote drug accumulation in subcutaneous tumors. In a B16F10-bearing mouse model, Sup-TDDS treatment demonstrates significant anti-tumor effects in primary and recurrent melanoma, benefiting from the synergistic effects of Ce6 and trametinib. These results underscore that Sup-TDDS's transdermal properties allow non-invasive melanoma therapy, implying the potential of nanodrugs containing pendant disulfides for transdermal treatment of skin illnesses.

Formulation development, characterization, and mechanistic PBPK modeling of metoclopramide loaded halloysite nanotube (HNT) based drug-in-adhesive type transdermal drug delivery system

Metoclopramide is an antiemetic agent prescribed for motion sickness, cancer chemotherapy, and pregnancy. The present work aimed to design a metoclopramide-loaded halloysite nanotubes (HNTs) drug-in-adhesive transdermal drug delivery system. Four formulations F1, F2, and F3 with different ratios of HNTs to metoclopramide and a F4 without HNTs were developed using acrylic adhesive DURO-TAK 387-2510 by the solvent casting method. These formulated patches were thoroughly evaluated and in-vitro release and permeation studies were performed. The optimized formulation was analyzed using skin irritation, SEM, DSC, and FTIR studies. The GASTROPLUS TCAT model was used to predict the in-vivo performance. HNT-based formulations exhibited controlled drug release, achieving approximately 60% in 4 h, compared to over 80% release in the same period from the formulation without HNT. The optimized formulation (F3) demonstrated a lag time of 1.802 h with a flux of 0.103 mg/cm2/hr. The shelf life was 19.279 months at 5 ± 3 °C. The Cmax, Tmax, AUCt, and AUCinf were predicted as 40.84 ng/mL, 6.32 h, 561.51 ng/mL×h and 599.61 ng/mL×h for a 30 mg patch. The study demonstrated that metoclopramide can be effectively loaded into HNTs and proved safe and effective in drug-in-adhesive type transdermal systems using HNTs as a drug carrier.

Recent advances in chitosan-based smart hydrogel for drug delivery systems

Achieving sustainable and controllable drug delivery is a highly effective disease treatment approach. Chitosan hydrogels, with their unique three-dimensional (3D) porous structures, offer tunable capacity, controllable degradation, various stimuli sensitivities, and the ability to encapsulate therapeutic agents. These characteristics provide chitosan hydrogels with inherent advantages as vehicles for drug delivery systems. In recent years, there has been a notable shift toward embracing the "back-to-nature" ethos, with biomass materials emerging as promising candidates for constructing chitosan hydrogels used in controlled drug release applications. This trend is sustained by their biodegradability, biocompatibility, and non-toxic properties, emphasizing their unique benefits and innovative features. These hydrogels exhibit sensitivity to various factors such as temperature, pH, ion concentration, light, magnetic fields, redox, ultrasound, and multi-responsiveness, offering opportunities for finely tuned drug release mechanisms. This review comprehensively outlines fabrication methods, properties, and biocompatibility of chitosan hydrogel, as well as modification strategies and stimuli-responsive mechanisms. Furthermore, their potential applications in subcutaneous (wound dressing), parental (transdermal drug delivery), oral (gastrointestinal tract), and facial (ophthalmic and brain) drug delivery are briefly discussed. The challenges in clinical application and the future outlook of chitosan-based smart hydrogel are also highlighted.

Transdermal delivery of elastin peptide assisted by betaine-based deep eutectic solvent to ameliorate skin photoaging

The unique amino acid composition of elastin peptide (EP) makes it an excellent resource to obtain antioxidant peptides. It exhibits high elastase inhibitory activity with the potential to resist skin aging and is currently used in a many cosmetic products. However, the inherent low permeability of the skin limits its ability to penetrate the skin. To address this issue, a deep eutectic solvent (SAB) with excellent bioactivity was synthesized from betaine and succinic acid and used as a permeation enhancer to improve the absorption and utilization of EP in this paper. The results showed that low SAB concentrations significantly increased the transdermal delivery of EP. The 3D epidermal skin model (EpiKutis®) demonstrated that SAB/EP induced the synthesis of hyaluronic acid (HA) and filaggrin (FLG), accelerated skin barrier repair, and reduced water loss. Additionally, the zebrafish embryonic model showed that SAB/EP could reduce melanin secretion, decrease melanin deposition, and have an ameliorative effect on skin photoaging. Cellular experiments proved that SAB/EP can stimulate human skin fibroblasts to secrete procollagen I and elastin, improving skin elasticity and anti-wrinkle. The combination of EP and DES is a new attempt that is expected to be used as a safe and effective anti-wrinkle cosmetic material.

Development, Statistical Optimization, and Characterization of Resveratrol-Containing Solid Lipid Nanoparticles (SLNs) and Determination of the Efficacy in Reducing Neurodegenerative Symptoms Related to Alzheimer's Disease: In Vitro and In Vivo Study

Resveratrol (RSV), as a natural polyphenol exhibiting antioxidative properties, is studied in the treatment of neurodegenerative diseases. However, RSV has low oral bioavailability. In this study and in order to overcome the issue, RSV was encapsulated into the solid lipid nanoparticles (SLNs). In this study, RSV-loaded solid lipid nanoparticles (RSV-SLNs) were prepared by the solvent emulsification-evaporation technique, and their physicochemical properties were optimized using Box-Behnken response surface methodology. The morphology of the particles was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The neuroprotective effects of the nanoparticles were investigated in animal models using the Morris water maze (MWM). Then after, the rats were sacrificed, their brains were collected, and the extent of lipid peroxidase (LPO) as well as the level of reduced glutathione (GSH) were determined in the hippocampus section samples. Finally, the collected brain tissues were histologically studied. The particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE%), and drug loading (DL%) of the optimized nanoparticles were 104.5 ± 12.3 nm, 0.322 ± 0.11, -3.1 ± 0.15 mV, 72.9 ± 5.31% and 14.6 ± 0.53%, respectively. The microscopic images revealed spherically shaped and nonaggregated nanoparticles. The in vivo studies demonstrated higher efficiency of RSV-SLN in the reduction of escape latency time and improvement in the time spent in the target quadrant compared to free RSV. Moreover, it was demonstrated that RSV-SLN posed a higher potency in the reduction of LPO as well as elevation of the GSH levels in the brain samples. The histological studies revealed a decline in neural degeneration and an improvement in the CA1 pyramidal cell morphology. The obtained data revealed that RSV-SLNs caused more reduction in Alzheimer-related symptoms rather than free RSV.

A compact and low-frequency drive ultrasound transducer for facilitating cavitation-assisted drug permeation via skin

Low-frequency sonophoresis has emerged as a promising minimally invasive transdermal drug delivery method. However, effectively inducing cavitation on the skin surface with a compact, low-frequency ultrasound transducer poses a significant challenge. This paper presents a modified design of a low-frequency ultrasound transducer capable of generating ultrasound cavitation on the skin surfaces. The transducer comprises a piezoelectric ceramic disk and a bowl-shaped acoustic resonator. A conical slit structure was incorporated into the modified transducer design to amplify vibration displacement and enhance the maximum sound pressure. The FEM-based simulation results confirmed that the maximum sound pressure at the resonance frequency of 78 kHz was increased by 1.9 times that of the previous design. Ultrasound cavitation could be experimentally observed on the gel surface. Moreover, 3 min of ultrasound treatment significantly improved the caffeine permeability across an artificial membrane. These results demonstrated that this transducer holds promise for enhancing drug permeation by generating ultrasound cavitation on the skin surface.

Semi-invasive wearable clinic: Solution-processed smart microneedle electronics for next-generation integrated diagnosis and treatment

The integrated smart electronics for real-time monitoring and personalized therapy of disease-related analytes have been gradually gaining tremendous attention. However, human tissue barriers, including the skin barrier and brain-blood barrier, pose significant challenges for effective biomarker detection and drug delivery. Microneedle (MN) electronics present a promising solution to overcome these tissue barriers due to their semi-invasive structures, enabling effective drug delivery and target-analyte detection without compromising the tissue configuration. Furthermore, MNs can be fabricated through solution processing, facilitating large-scale manufacturing. This review provides a comprehensive summary of the recent three-year advancements in smart MNs development, categorized as follows. First, the solution-processed technology for MNs is introduced, with a focus on various printing technologies. Subsequently, smart MNs designed for sensing, drug delivery, and integrated systems combining diagnosis and treatment are separately summarized. Finally, the prospective and promising applications of next-generation MNs within mediated diagnosis and treatment systems are discussed.

Pretreatment of microneedles enhances passive transdermal administration of pilocarpine and pilocarpine-induced sweat production in humans

The development of an effective transdermal drug delivery protocol to eccrine sweat glands is important for the advancement of research on the human sweating response. We investigated whether microneedle treatment prior to the application of pilocarpine, a hydrophilic and sudorific agent that does not induce sweating due to a limited percutaneous passive diffusion by skin application alone, augments sweat production. We applied three microneedle arrays to forearm skin sites simultaneously (n = 20). Upon removal of the microneedles, 1 % pilocarpine was applied to each site for 5-, 15-, and 30-min for the assessment of sweat gland function. In parallel, pilocarpine was administered by transdermal iontophoresis (5-min) at a separate site. Sweat rate was assessed continuously via the ventilated capsule technique. Pilocarpine augmented sweat rate at the 15- and 30-min periods as compared to the application at 5-min. The sweating responses induced by the 15- and 30-min application of pilocarpine were equivalent to ∼ 80 % of that measured at the iontophoretically treated sites. Notably, we observed a correlation in sweat rate between these two transdermal drug delivery methods. Altogether, our findings show that pre-treatment of microneedle arrays can enhance transdermal delivery efficiency of pilocarpine to human eccrine sweat glands.

Advances in Transdermal Delivery of Antimicrobial Peptides for Wound Management: Biomaterial-Based Approaches and Future Perspectives

Antimicrobial peptides (AMPs), distinguished by their cationic and amphiphilic nature, represent a critical frontier in the battle against antimicrobial resistance due to their potent antimicrobial activity and a broad spectrum of action. However, the clinical translation of AMPs faces hurdles, including their susceptibility to degradation, limited bioavailability, and the need for targeted delivery. Transdermal delivery has immense potential for optimizing AMP administration for wound management. Leveraging the skin's accessibility and barrier properties, transdermal delivery offers a noninvasive approach that can circumvent systemic side effects and ensure sustained release. Biomaterial-based delivery systems, encompassing nanofibers, hydrogels, nanoparticles, and liposomes, have emerged as key players in enhancing the efficacy of transdermal AMP delivery. These biomaterial carriers not only shield AMPs from enzymatic degradation but also provide controlled release mechanisms, thereby elevating stability and bioavailability. The synergistic interaction between the transdermal approach and biomaterial-facilitated formulations presents a promising strategy to overcome the multifaceted challenges associated with AMP delivery. Integrating advanced technologies and personalized medicine, this convergence allows the reimagining of wound care. This review amalgamates insights to propose a pathway where AMPs, transdermal delivery, and biomaterial innovation harmonize for effective wound management.

Anti-Nociceptive Effect of Sufentanil Polymeric Dissolving Microneedle on Male Mice by Hot Plate Technique

Background

Despite the widespread use of opioids to manage severe pain, its systemic administration results in side effects. Among the subcutaneous and transdermal drug delivery systems developed to deal with adverse effects, microneedles have drawn attention due to their rapid action, high drug bioavailability, and improved permeability. Sufentanil (SUF) is an effective injectable opioid for treating severe pain. In this study, we investigated the analgesic effects of SUF using dissolvable microneedles.

Methods

SUF polymeric dissolvable microneedles were constructed through the mold casting method and characterized by SEM and FTIR analysis. Its mechanical strength was also investigated using a texture analyzer. Fluorescence microscopy was applied in vitro to measure the penetration depth of microneedle arrays. Irritation and microchannel closure time, drug release profile, and hemocompatibility test were conducted for the validation of microneedle efficiency. Hot plate test was also used to investigate the analgesic effect of microneedle in an animal model.

Results

Local administration of SUF via dissolving microneedles had an effective analgesic impact. One hour after administration, there was no significant difference between the subcutaneous and the microneedle groups, and the mechanical properties were within acceptable limits.

Conclusion

Microneedling is an effective strategy in immediate pain relief compared to the traditional methods.

Progress in Topical and Transdermal Drug Delivery Research-Focus on Nanoformulations

Skin is the largest organ and a multifunctional interface between the body and its environment. It acts as a barrier against cold, heat, injuries, infections, chemicals, radiations or other exogeneous factors, and it is also known as the mirror of the soul. The skin is involved in body temperature regulation by the storage of fat and water. It is an interesting tissue in regard to the local and transdermal application of active ingredients for prevention or treatment of pathological conditions. Topical and transdermal delivery is an emerging route of drug and cosmetic administration. It is beneficial for avoiding side effects and rapid metabolism. Many pharmaceutical, technological and cosmetic innovations have been described and patented recently in the field. In this review, the main features of skin morphology and physiology are presented and are being followed by the description of classical and novel nanoparticulate dermal and transdermal drug formulations. The biophysical aspects of the penetration of drugs and cosmetics into or across the dermal barrier and their investigation in diffusion chambers, skin-on-a-chip devices, high-throughput measuring systems or with advanced analytical techniques are also shown. The current knowledge about mathematical modeling of skin penetration and the future perspectives are briefly discussed in the end, all also involving nanoparticulated systems.

Fabrication, evaluation, and enhanced penetration of vinyl and cellulose-engineered transdermal patch of nifedipine using essential oil as penetration enhancer

The aim of this study was to develop and evaluate the transdermal patch formulations of nifedipine. The patch formulations containing nifedipine were prepared and optimized with different ratios of vinyl and cellulose-derived polymers, drug contents, and permeation enhancers. Among the various formulations, the patch formulation containing a 1:5 ratio of ethyl cellulose and polyvinyl pyrrolidone was selected for ex vivo pharmacokinetic study based on in vitro permeation studies using stratum corneum of the pig's skin. The cumulative percentage release after the transdermal administration of the optimized patch formulation was 71.43%, and the plasma concentration of nifedipine was maintained for 16 hrs. The physicochemical evaluation study including flatness, thickness, moisture content and uptake, drug content in vitro release, and ex vivo permeation indicated satisfactory results. The formulation batch with clove oil as a penetration enhancer has shown better ex vivo permeation as compared to the formulations without enhancers and another synthetic enhancer. These results suggest that the optimized patch formulation Q3 could be further developed for clinical applications, providing the therapeutic plasma level of nifedipine over an extended period. Hence analyzing the results of the evaluation tests, in vitro and ex vivo data on the preparation and optimization of nifedipine-loaded transdermal patch, it can be concluded that the formulation shows its feasibility as an effective transdermal delivery system for nifedipine.

Novel Drug Delivery Systems: An Important Direction for Drug Innovation Research and Development

The escalating demand for enhanced therapeutic efficacy and reduced adverse effects in the pharmaceutical domain has catalyzed a new frontier of innovation and research in the field of pharmacy: novel drug delivery systems. These systems are designed to address the limitations of conventional drug administration, such as abbreviated half-life, inadequate targeting, low solubility, and bioavailability. As the disciplines of pharmacy, materials science, and biomedicine continue to advance and converge, the development of efficient and safe drug delivery systems, including biopharmaceutical formulations, has garnered significant attention both domestically and internationally. This article presents an overview of the latest advancements in drug delivery systems, categorized into four primary areas: carrier-based and coupling-based targeted drug delivery systems, intelligent drug delivery systems, and drug delivery devices, based on their main objectives and methodologies. Additionally, it critically analyzes the technological bottlenecks, current research challenges, and future trends in the application of novel drug delivery systems.

Revolutionizing transdermal drug delivery: unveiling the potential of cubosomes and ethosomes

The area of drug delivery systems has witnessed significant advancements in recent years, with a particular focus on improving efficacy, stability, and patient compliance. Transdermal drug delivery offers numerous benefits compared to conventional methods of drug administration through the skin. It helps in avoiding gastric irritation, hepatic first-pass metabolism, and gastric degradation of the drug. It bypasses the gastrointestinal tract, eliminating the risk of first-pass metabolism and allowing drugs to be administered without being affected by pH, enzymes, or intestinal bacteria. Additionally, it allows for sustained release of the drug, is noninvasive, and enhances patient adherence to the treatment regimen. The transdermal drug delivery system (TDDS) can serve as an alternative route for drug administration in individuals who cannot tolerate oral medications, experience nausea, or are unconscious. When compared to intravenous, hypodermic, and other parenteral routes, TDDS stands out due to its ability to eliminate pain, reduce the risk of infection, and prevent disease transmission associated with needle reuse. Consequently, the overall patient compliance is significantly improved with the utilization of TDDS. Among the noteworthy developments are cubosomes and ethosomes, two distinct yet promising carriers that have garnered attention for their unique properties. In conclusion, this review synthesizes the current knowledge on cubosomes and ethosomes, shedding light on their individual strengths and potential synergies. The exploration of their application in various therapeutic areas underscores their versatility and establishes them as key players in the evolving landscape of drug delivery systems.

A piezoelectric-driven microneedle platform for skin disease therapy

With over a million cases detected each year, skin disease is a global public health problem that diminishes the quality of life due to its difficulty to eradicate, propensity for recurrence, and potential for post-treatment scarring. Photodynamic therapy (PDT) is a treatment with minimal invasiveness or scarring and few side effects, making it well tolerated by patients. However, this treatment requires further research and development to improve its effective clinical use. Here, a piezoelectric-driven microneedle (PDMN) platform that achieves high efficiency, safety, and non-invasiveness for enhanced PDT is proposed. This platform induces deep tissue cavitation, increasing the level of protoporphyrin IX and significantly enhancing drug penetration. A clinical trial involving 25 patients with skin disease was conducted to investigate the timeliness and efficacy of PDMN-assisted PDT (PDMN-PDT). Our findings suggested that PDMN-PDT boosted treatment effectiveness and reduced the required incubation time and drug concentration by 25% and 50%, respectively, without any anesthesia compared to traditional PDT. These findings suggest that PDMN-PDT is a safe and minimally invasive approach for skin disease treatment, which may improve the therapeutic efficacy of topical medications and enable translation for future clinical applications.

Mesoporous silica coated spicules for photodynamic therapy of metastatic melanoma

We report on the fabrication of mesoporous silicon dioxide coated Haliclona sp. spicules (mSHS) to enhance the delivery of the insoluble photosensitizer protoporphyrin IX (PpIX) into deep skin layers and mediate photodynamic therapy for metastatic melanoma in mice. The mSHS are dispersed sharp edged and rod-like micro-particles with a length of approximate 143.6 ± 6.4 μm and a specific surface area of 14.9 ± 3.4 m2/g. The mSHS can be topically applied to the skin, adapting to any desired skin area and lesion site. The insoluble PpIX were incorporated into the mesoporous silica coating layers of mSHS (mSHS@PpIX) with the maximum PpIX loading capacity of 120.3 ± 3.8 μg/mg. The mSHS@PpIX significantly enhanced the deposition of PpIX in the viable epidermis (5.1 ± 0.4 μg/cm2) and in the dermis (0.5 ± 0.2 μg/cm2), which was 154 ± 11-fold and 22 ± tenfold higher than those achieved by SHS, respectively. Topical delivery of PpIX using mSHS (mSHS@PpIX) completely eradicated the primary melanoma in mice in 10 days without recurrence or metastasis over 60 days. These results demonstrate that mSHS can be a promising topical drug delivery platform for the treatment of diverse cutaneous diseases, such as metastatic melanoma.

Eugenol-Loaded Transethosomal Gel for Improved Skin Delivery and Treatment of Atopic Dermatitis

Atopic dermatitis is a skin condition characterized by lichenification (thickening and increased skin marking), eczematous lesions, dry skin, itching, and pruritus. Eugenol is an aromatic polyphenolic compound that has attracted the attention of researchers due to its anti-inflammatory, anti-oxidant, and anti-cancer properties. The primary goal of the present study was to develop and evaluate eugenol-loaded transethosomes for the treatment of AD. Eugenol-loaded transethosomes were formulated using the ethanol injection method and subsequently subjected to particle size analysis, zeta potential, entrapment efficiency, deformability index, and HRTEM analysis. Transethosomal gel was prepared by direct-dispersion method by using Carbopol 940®. Results showed transethosomes to be lipid bilayer structures with acceptable size, and high entrapment efficiency. Transethosomal formulation showed shear-thinning behavior. Eugenol-loaded transethosomal gel was significantly able to enhance the retention of the drug in the skin. Transethosomal gel was significantly able to reduce Ear thickness, DLC, TLC, and IL-6 levels in mice model of AD. These results indicate that the eugenol-loaded transethosomal gel could be a promising carrier for the topical administration of eugenol for the treatment of AD.

Effects of imidazolium ionic liquids on skin barrier lipids - Perspectives for drug delivery

Ionic liquids (ILs) have great potential to facilitate transdermal and topical drug delivery. Here, we investigated the mechanism of action of amphiphilic ILs 1-methyl-3-octylimidazolium bromide (C8MIM) and 3-dodecyl-1-methylimidazolium bromide (C12MIM) in skin barrier lipid models in comparison to their complex effects in human skin. C8MIM incorporated in a skin lipid model was a better permeation enhancer than C12MIM for water and model drugs, theophylline and diclofenac. Solid state 2H NMR and X-ray diffraction indicated that both ILs prefer the cholesterol-rich regions in skin lipids without significantly perturbing their lamellar arrangement and that C8MIM induces the formation of an isotropic lipid phase to a greater extent compared to C12MIM. C12MIM applied topically to the lipid model or human skin as a pretreatment was more potent than C8MIM. When co-applied with the drugs to human skin, aqueous C12MIM was more potent than C8MIM in enhancing theophylline permeation, but neither IL affected (even decreased) diclofenac permeation. Thus, the IL's ability to permeabilize skin lipid barrier is strongly modulated by its ability to reach the site of action and its interactions with drug and solvent. Such an interplay is far from trivial and requires detailed investigation to realize the full potential of ILs.

Multifunctional Deep Eutectic Solvent-Based Microemulsion for Transdermal Delivery of Artemisinin

As a serious public health issue, malaria threatens the health of millions of people. Artemisinin, a gift from traditional Chinese medicine, has been used in the treatment of malaria and has shown good therapeutic efficiency. However, due to its low solubility, poor bioavailability, and short half-life time, some smart delivery strategies are still required. Herein, a multifunctional DES prepared from ibuprofen and menthol was prepared. This DES was shown to efficiently promote the solubility of artemisinin up to 400-fold. Then, it was further applied as the oil phase to construct an O/W microemulsion with the help of Tween-80 + Span-20 mixed surfactants. The prepared microemulsion displayed high efficiency in improving the permeability of artemisinin, which can be ascribed to the presence of the permeation enhancer menthol in DES and the microstructure of the O/W microemulsion. Moreover, the simultaneous permeation of artemisinin and ibuprofen further indicated the potential benefits of the presented formulation in the treatment of malaria. To sum up, the microemulsion based on multifunctional DES presented herein provided an effective method for transdermal delivery of artemisinin.

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.

Glycols: The ubiquitous solvent for dermal formulations

Glycols stand out as one of the most commonly employed safe and effective excipients for pharmaceutical and cosmeceutical products. Their widespread adoption can be attributed to their exceptional solvency characteristics and their ability to interact effectively with skin lipids and keratin for permeation enhancement. Notably, propylene glycol enjoys significant popularity in this regard. Ongoing research endeavours have been dedicated to scrutinising the impact of glycols on dermal drug delivery and shedding light on the intricate mechanisms by which glycols enhance skin permeation. This review aims to mitigate the discordance within the existing literature, assemble a holistic understanding of the impact of glycols on the percutaneous absorption of active compounds and furnish the reader with a profound comprehension of the foundational facets pertaining to their skin permeation enhancement mechanisms, while simultaneously delving deeper into the intricacies of these processes.

Inkjet Printing of Pharmaceuticals

Inkjet printing (IJP) is an additive manufacturing process that selectively deposits ink materials, layer-by-layer, to create 3D objects or 2D patterns with precise control over their structure and composition. This technology has emerged as an attractive and versatile approach to address the ever-evolving demands of personalized medicine in the healthcare industry. Although originally developed for nonhealthcare applications, IJP harnesses the potential of pharma-inks, which are meticulously formulated inks containing drugs and pharmaceutical excipients. Delving into the formulation and components of pharma-inks, the key to precise and adaptable material deposition enabled by IJP is unraveled. The review extends its focus to substrate materials, including paper, films, foams, lenses, and 3D-printed materials, showcasing their diverse advantages, while exploring a wide spectrum of therapeutic applications. Additionally, the potential benefits of hardware and software improvements, along with artificial intelligence integration, are discussed to enhance IJP's precision and efficiency. Embracing these advancements, IJP holds immense potential to reshape traditional medicine manufacturing processes, ushering in an era of medical precision. However, further exploration and optimization are needed to fully utilize IJP's healthcare capabilities. As researchers push the boundaries of IJP, the vision of patient-specific treatment is on the horizon of becoming a tangible reality.

Advancements in Skin-Mediated Drug Delivery: Mechanisms, Techniques, and Applications

Skin-mediated drug delivery methods currently are receiving significant attention as a promising approach for the enhanced delivery of drugs through the skin. Skin-mediated drug delivery offers the potential to overcome the limitations of traditional drug delivery methods, including oral administration and intravenous injection. The challenges associated with drug permeation through layers of skin, which act as a major barrier, are explored, and strategies to overcome these limitations are discussed in detail. This review categorizes skin-mediated drug delivery methods based on the means of increasing drug permeation, and it provides a comprehensive overview of the mechanisms and techniques associated with these methods. In addition, recent advancements in the application of skin-mediated drug delivery are presented. The review also outlines the limitations of ongoing research and suggests future perspectives of studies regarding the skin-mediated delivery of drugs.

A comprehensive review on transethosomes as a novel vesicular approach for drug delivery through transdermal route

Drug delivery through transdermal route is one of the effective methods for the application of drugs. It overcomes many drawbacks which are encountered with the oral route. Moreover, many drugs are not able to pass through the stratum corneum, which is the main barrier for the transdermal drug delivery. Formation of ultra-deformable vesicles (UDVs) is a novel technique for the transdermal applications of the drugs. Transethosomes (TEs), ethosomes, and transferosomes are all part of the UDV. Because of the presence of increased concentrations of ethanol, phospholipids, and edge activators, TEs provide improved drug permeation through the stratum corneum. Because of the elasticity of TEs, drug penetration into the deeper layer of skin also increases. TEs can be prepared using a variety of techniques, including the cold method, hot method, thin film hydration method, and the ethanol injection method. It increases patient adherence and compliance because it is a non-invasive procedure of administering drugs. Characterization of the TEs includes pH determination, size and shape, zeta potential, particle size determination, transition temperature, drug content, vesicle stability, and skin permeation studies. These vesicular systems can be utilized to deliver a variety of medications transdermally, including analgesics, antibiotics, antivirals, and anticancer and arthritis medications. This review aims to describe vesicular approaches that had been used to overcome the barrier for the transdermal delivery of drug and also describes brief composition, method of preparation, characterization tests, mechanism of penetration of TEs, as well as highlighted various applications of TEs in medicine.

In vitro and Ex vivo study targeting the development of a Lavandula stoechas L. (Ustukhuddūs) loaded Unani Transdermal patch: Implication of Unani Medicine in the treatment of Nisyan (Dementia)

Ustukhuddūs (Lavandula stoechas L.) has been extensively used orally and topically in treating various neurological disorders, including dementia. The optimum potential of traditional dosage forms of Ustukhuddūs is limited for various reasons. Transdermal drug delivery system (TDDS) is a novel means of drug delivery and is known to overcome the drawbacks associated with traditional dosage forms. The current study aimed at fabricating and evaluating Ustukhuddūs hydro-alcoholic extract (UHAE) and essential oil (UEO) loaded matrix-type transdermal patches having a combination of hydrophilic - hydroxyl propyl methyl cellulose (HPMC) and hydrophobic - ethyl cellulose (EC) polymers. ATR-FTIR, DSC, XRD, and SEM analysis were carried out to study drug-polymer interactions, confirming the formation of developed patches and drug compatibility with excipients. We assessed the fabricated patches to evaluate their physicochemical properties, in vitro drug release, and permeation characteristics via ex vivo experiments. The physicochemical characteristics of patches showcased the development of good and stable films with clarity, smoothness, homogeneity, optimum flexibility and free from causing skin irritancy or sensitization. In vitro drug release and ex vivo permeation profile of developed patches were evaluated employing Franz diffusion cells. UHAE and UEO patches exhibited a cumulative drug release of 81.61 and 85.24 %, respectively, in a sustained-release manner and followed non-Fickian release mechanisms. The ex vivo permeation data revealed 66.82 % and 76.41 % of drug permeated from UHAE and UEO patches, respectively. The current research suggests that the formulated patches are more suitable for TDDS and hold potential significance in the treatment of dementia, contributing to enhanced patient compliance, thereby highlighting the implication of Unani Medicine in Nisyan (Dementia) treatment.