Overcoming skin barriers through advanced transdermal drug delivery approaches

A Transdermal Prion-Bionics Supermolecule as a RAB3A Antagonist for Enhancing Facial Youthfulness

The mechanism research of skin wrinkles, conducted on volunteers underwent high-intensity desk work and mice subjected to partial sleep deprivation, revealed a significant reduction in dermal thickness associated with the presence of wrinkles. This can be attributed to the activation of facial nerves in a state of hysteria due to an abnormally elevated interaction between SNAP25 and RAB3A proteins involved in the synaptic vesicle cycle (SVC). Facilitated by AI-assisted structural design, a refined peptide called RSIpep is developed to modulate this interaction and normalize SVC. Drawing inspiration from prions, which possess the ability to protect themselves against proteolysis and invade neighboring nerve cells through macropinocytosis, RSIpep is engineered to demonstrate a GSH-responsive reversible self-assembly into a prion-like supermolecule (RSIprion). RSIprion showcases protease resistance, micropinocytosis-dependent cellular internalization, and low adhesion with constituent molecules in the cuticle, thereby endowing it with the transdermic absorption and subsequent biofunction in redressing the frenzied SVC. As a facial mud mask, it effectively reduces periorbital and perinasal wrinkles in the human face. Collectively, RSIprion not only presents a clinical potential as an anti-wrinkle prion-like supermolecule, but also exemplifies a reproducible instance of bionic strategy-guided drug development that bestows transdermal ability upon the pharmaceutical molecule.

Transdermal gene delivery

Gene delivery has revolutionized conventional medical approaches to vaccination, cancer, and autoimmune diseases. However, current gene delivery methods are limited to either intravenous administration or direct local injections, failing to achieve well biosafety, tissue targeting, drug retention, and transfection efficiency for desired therapeutic outcomes. Transdermal drug delivery based on various delivery strategies can offer improved therapeutic potential and superior patient experiences. Recently, there has been increased foundational and clinical research focusing on the role of the transdermal route in gene delivery and exploring its impact on the efficiency of gene delivery. This review introduces the recent advances in transdermal gene delivery approaches facilitated by drug formulations and medical devices, as well as discusses their prospects.

Medicinal Anti-Inflammatory Patch Loaded with Lavender Essential Oil

Transdermal drug delivery offers a promising alternative for administering medications like ibuprofen, known for its analgesic and anti-inflammatory properties, with reduced gastrointestinal side effects compared to oral administration. This study explored the potential synergistic effects of combining ibuprofen with lavender essential oil (LEO) in transdermal patches. The composition of LEO was analyzed, revealing predominant compounds such as linalyl acetate and linalool, which are known for their analgesic and anti-inflammatory properties. The physicochemical properties of the patches were investigated, indicating improved cohesion with the addition of LEO. Additionally, thermal stability assessments demonstrated enhanced stability with LEO incorporation with an increase in onset decomposition temperature from 49.0 to 67.9 °C. The antioxidant activity of patches containing LEO was significantly higher with a free radical scavenging ability of 79.13% RSA compared to 60% RSA in patches without LEO. Release and permeation studies showed that patches with LEO exhibited an increased permeation of ibuprofen through the skin with 74.40% of the drug released from LEO-containing patches compared to 36.29% from patches without LEO after 24 h. Moreover, the permeation rate was notably faster with LEO, indicating quicker therapeutic effects. The inclusion of LEO in transdermal patches containing ibuprofen holds promise for enhancing drug delivery efficiency and therapeutic effectiveness, offering a potential strategy for improved pain management with reduced side effects.

Statistical design and optimization of nano-transfersomes based chitosan gel for transdermal delivery of cefepime

OBJECTIVES

This research aimed to overcome challenges posed by cefepime excessive elimination rate and poor patient compliance by developing transdermal delivery system using nano-transfersomes based chitosan gel.

METHODS

Rotary evaporation-sonication method and the Box-Behnken model were used to prepare cefepime loaded nano-transfersomes (CPE-NTFs). The physiochemical characterization of CPE-NTFs were analyzed including DLS, deformability index, DSC and antimicrobial study. Optimized CPE-NTFs loaded into chitosan gel and appropriately characterized. In vitro release, ex vivo and in vivo studies were performed.

RESULTS

The CPE-NTFs were physically stable with particle size 222.6 ± 1.8 nm, polydispersity index 0.163 ± 0.02, zeta potential -20.8 ± 0.1 mv, entrapment efficiency 81.4 ± 1.1% and deformability index 71 ± 0.2. DSC analysis confirmed successful drug loading and thermal stability. FTIR analysis showed no chemical interaction among the excipients of CPE-NTFs gel. The antibacterial activity demonstrated a remarkable reduction in the minimum inhibitory concentration of cefepime when incorporated into nano-transfersomes. CPE-NTFs based chitosan gel (CPE-NTFs gel) showed significant physicochemical properties. In vitro release studies exhibited sustained release behavior over 24 h, and ex vivo studies indicated enhanced permeation and retention compared to conventional cefepime gel. In vivo skin irritation studies confirmed CPE-NTFs gel was nonirritating and biocompatible for transdermal delivery.

CONCLUSION

This research showed nano-transfersomes based chitosan gel is a promising approach for cefepime transdermal delivery and provides sustained release of cefepime.

Deep eutectic solvent self-assembled reverse nanomicelles for transdermal delivery of sparingly soluble drugs

BACKGROUND

Transdermal delivery of sparingly soluble drugs is challenging due to their low solubility and poor permeability. Deep eutectic solvent (DES)/or ionic liquid (IL)-mediated nanocarriers are attracting increasing attention. However, most of them require the addition of auxiliary materials (such as surfactants or organic solvents) to maintain the stability of formulations, which may cause skin irritation and potential toxicity.

RESULTS

We fabricated an amphiphilic DES using natural oxymatrine and lauric acid and constructed a novel self-assembled reverse nanomicelle system (DES-RM) based on the features of this DES. Synthesized DESs showed the broad liquid window and significantly solubilized a series of sparingly soluble drugs, and quantitative structure-activity relationship (QSAR) models with good prediction ability were further built. The experimental and molecular dynamics simulation elucidated that the self-assembly of DES-RM was adjusted by noncovalent intermolecular forces. Choosing triamcinolone acetonide (TA) as a model drug, the skin penetration studies revealed that DES-RM significantly enhanced TA penetration and retention in comparison with their corresponding DES and oil. Furthermore, in vivo animal experiments demonstrated that TA@DES-RM exhibited good anti-psoriasis therapeutic efficacy as well as biocompatibility.

CONCLUSIONS

The present study offers innovative insights into the optimal design of micellar nanodelivery system based on DES combining experiments and computational simulations and provides a promising strategy for developing efficient transdermal delivery systems for sparingly soluble drugs.

Key Transdermal Patch Using Cannabidiol-Loaded Nanocarriers with Better Pharmacokinetics in vivo

Purpose

Cannabidiol (CBD) is a promising therapeutic drug with low addictive potential and a favorable safety profile. However, CBD did face certain challenges, including poor solubility in water and low oral bioavailability. To harness the potential of CBD by combining it with a transdermal drug delivery system (TDDS). This innovative approach sought to develop a transdermal patch dosage form with micellar vesicular nanocarriers to enhance the bioavailability of CBD, leading to improved therapeutic outcomes.

Methods

A skin-penetrating micellar vesicular nanocarriers, prepared using nano emulsion method, cannabidiol loaded transdermal nanocarriers-12 (CTD-12) was presented with a small particle size, high encapsulation efficiency, and a drug-loaded ratio for CBD. The skin permeation ability used Strat-M™ membrane with a transdermal diffusion system to evaluate the CTD and patch of CTD-12 (PCTD-12) within 24 hrs. PCTD-12 was used in a preliminary pharmacokinetic study in rats to demonstrate the potential of the developed transdermal nanocarrier drug patch for future applications.

Results

In the transdermal application of CTD-12, the relative bioavailability of the formulation was 3.68 ± 0.17-fold greater than in the free CBD application. Moreover, PCTD-12 indicated 2.46 ± 0.18-fold higher relative bioavailability comparing with free CBD patch in the ex vivo evaluation. Most importantly, in the pharmacokinetics of PCTD-12, the relative bioavailability of PCTD-12 was 9.47 ± 0.88-fold higher than in the oral application.

Conclusion

CTD-12, a transdermal nanocarrier, represents a promising approach for CBD delivery, suggesting its potential as an effective transdermal dosage form.

Nanocarrier-Integrated Microneedles: Divulging the Potential of Novel Frontiers for Fostering the Management of Skin Ailments

The various kinds of nanocarriers (NCs) have been explored for the delivery of therapeutics designed for the management of skin manifestations. The NCs are considered as one of the promising approaches for the skin delivery of therapeutics attributable to sustained release and enhanced skin penetration. Despite the extensive applications of the NCs, the challenges in their delivery via skin barrier (majorly stratum corneum) have persisted. To overcome all the challenges associated with the delivery of NCs, the microneedle (MN) technology has emerged as a beacon of hope. Programmable drug release, being painless, and its minimally invasive nature make it an intriguing strategy to circumvent the multiple challenges associated with the various drug delivery systems. The integration of positive traits of NCs and MNs boosts therapeutic effectiveness by evading stratum corneum, facilitating the delivery of NCs through the skin and enhancing their targeted delivery. This review discusses the barrier function of skin, the importance of MNs, the types of MNs, and the superiority of NC-loaded MNs. We highlighted the applications of NC-integrated MNs for the management of various skin ailments, combinational drug delivery, active targeting, in vivo imaging, and as theranostics. The clinical trials, patent portfolio, and marketed products of drug/NC-integrated MNs are covered. Finally, regulatory hurdles toward benchtop-to-bedside translation, along with promising prospects needed to scale up NC-integrated MN technology, have been deliberated. The current review is anticipated to deliver thoughtful visions to researchers, clinicians, and formulation scientists for the successful development of the MN-technology-based product by carefully optimizing all the formulation variables.

Hydrophobicity: The door to drug delivery

The engineering of intracellular delivery systems with the goal of achieving personalized medicine has been encouraged by advances in nanomaterial science as well as a greater understanding of diseases and of the biochemical pathways implicated in many disorders. The development of vectors able to transport the drug to a target location and release it only on demand is undoubtedly the primary issue. From a molecular perspective, the topography of drug carrier surfaces is directly related to the design of an effective drug carrier because it provides a physical hint to modifying its interactions with biological systems. For instance, the initial ratio of hydrophilic to hydrophobic surfaces and the changes brought about by external factors enable the release or encapsulation of a therapeutic molecule and the ability of the nanosystem to cross biological barriers and reach its target without causing systemic toxicity. The first step in creating new materials with enhanced functionality is to comprehend and characterize the interplay between hydrophilic and hydrophobic molecules at the molecular level. Therefore, the focus of this review is on the function of hydrophobicity, which is essential for matching the complexity of biological environments with the intended functionality.

Microsponges: Development, Characterization, and Key Physicochemical Properties

Microsponges are promising drug delivery carriers with versatile characteristics and controlled release properties for the delivery of a wide range of drugs. The microsponges will provide an optimized therapeutic effect, when delivered at the site of action without rupturing, then releasing the cargo at the predetermined time and area. The ability of the microsponges to effectively deliver the drug in a controlled manner depends on the material composition. This comprehensive review entails knowledge on the design parameters of an optimized microsponge drug delivery system and the controlled release properties of microsponges that reduces the side effects of drugs. Furthermore, the review delves into the fabrication techniques of microsponges, the mechanism of drug release from the microsponges, and the regulatory requirements of the U.S. Food and Drug Administration (FDA) for the successful marketing of microsponge formulation. The review also examines the patented formulations of microsponges. The prospects of these sophisticated drug delivery systems for improved clinical outcomes are highlighted.

Synergistic applications of cyclodextrin-based systems and metal-organic frameworks in transdermal drug delivery for skin cancer therapy

This review article explores the innovative field of eco-friendly cyclodextrin-based coordination polymers and metal-organic frameworks (MOFs) for transdermal drug delivery in the case of skin cancer therapy. We critically examine the significant advancements in developing these nanocarriers, with a focus on their unique properties such as biocompatibility, targeted drug release, and enhanced skin permeability. These attributes are instrumental in addressing the limitations inherent in traditional skin cancer treatments and represent a paradigm shift towards more effective and patient-friendly therapeutic approaches. Furthermore, we discuss the challenges faced in optimizing the synthesis process for large-scale production while ensuring environmental sustainability. The review also emphasizes the immense potential for clinical applications of these nanocarriers in skin cancer therapy, highlighting their role in facilitating targeted, controlled drug release which minimizes systemic side effects. Future clinical applications could see these nanocarriers being customized to individual patient profiles, potentially revolutionizing personalized medicine in oncology. With further research and clinical trials, these nanocarriers hold the promise of transforming the landscape of skin cancer treatment. With this study, we aim to provide a comprehensive overview of the current state of research in this field and outline future directions for advancing the development and clinical application of these innovative nanocarriers.

Secondary metabolites in topical infectious diseases and nanomedicine applications

Topical infection affects nearly one-third of the world's population; it may result from poor sanitation, hygienic conditions and crowded living and working conditions that accelerate the spread of topical infectious diseases. The problems associated with the anti-infective agents are drug resistance and long-term therapy. Secondary metabolites are obtained from plants, microorganisms and animals, but they are metabolized inside the human body. The integration of nanotechnology into secondary metabolites is gaining attention due to their interaction at the subatomic and skin-tissue levels. Hydrogel, liposomes, lipidic nanoparticles, polymeric nanoparticles and metallic nanoparticles are the most suitable carriers for secondary metabolite delivery. Therefore, the present review article extensively discusses the topical applications of nanomedicines for the effective delivery of secondary metabolites.

Skin Tolerability of Oleic Acid Based Nanovesicles Designed for the Improvement of Icariin and Naproxen Percutaneous Permeation

Deformable nanovesicles have a crucial role in topical drug delivery through the skin, due to their capability to pass intact the stratum corneum and epidermis (SCE) and significantly increase the efficacy and accumulation of payloads in the deeper layers of the skin. Namely, lipid-based ultradeformable nanovesicles are versatile and load bioactive molecules with different physicochemical properties. For this reason, this study aims to make oleic acid based nanovesicles (oleosomes) for the codelivery of icariin and sodium naproxen and increase their permeation through the skin. Oleosomes have suitable physicochemical properties and long-term stability for a potential dermal or transdermal application. The inclusion of oleic acid in the lipid bilayer increases 3-fold the deformable properties of oleosomes compared to conventional liposomes and significantly improves the percutaneous permeation of icariin and sodium naproxen through the human SCE membranes compared to hydroalcoholic solutions of both drugs. The tolerability studies on human volunteers demonstrate that oleosomes are safer and speed up the recovery of transepidermal water loss (TEWL) baselines compared to saline solution. These results highlight promising properties of icariin/sodium naproxen coloaded oleosomes for the treatment of skin disorders and suggest the potential future applications of these nanovesicles for further in vivo experiments.

Clinical significance of small extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma is an aggressive and heterogeneous malignancy originating from the bile duct epithelium. It is associated with poor prognosis and high mortality. The global incidence of cholangiocarcinoma is rising, and there is an urgent need for effective early diagnosis and treatment strategies to reduce the burden of this devastating tumor. Small extracellular vesicles, including exosomes and microparticles, are nanoscale vesicles formed by membranes that are released both normally and pathologically from cells, mediating the intercellular transfer of substances and information. Recent studies have demonstrated the involvement of small extracellular vesicles in numerous biological processes, as well as the proliferation, invasion, and metastasis of tumor cells. The present review summarizes the tumorigenic roles of small extracellular vesicles in the cholangiocarcinoma microenvironment. Owing to their unique composition, accessibility, and stability in biological fluids, small extracellular vesicles have emerged as ideal biomarkers for use in liquid biopsies for diagnosing and outcome prediction of cholangiocarcinoma. Specific tissue tropism, theoretical biocompatibility, low clearance, and strong biological barrier penetration of small extracellular vesicles make them suitable drug carriers for cancer therapy. Furthermore, the potential value of small extracellular vesicle-based therapies for cholangiocarcinoma is also reviewed.

Microneedle combined with iontophoresis and electroporation for assisted transdermal delivery of goniothalamus macrophyllus for enhancement sonophotodynamic activated cancer therapy

The underlying study was carried out aiming at transdermal drug delivery (TDD) of Goniothalamus macrophyllus as sono-photo-sensitizer (SPS) using microneedle (MN) arrays with iontophoresis (MN-IP), electroporation (MN-EP) in conjunction with applying photodynamic therapy (PDT), sonodynamic therapy (SDT) and sono-photodynamic therapy (SPDT) as an up-to-date activated cancer treatment modality. Study was conducted on 120 male Swiss Albino mice, inoculated with Ehrlich ascites carcinoma (EAC) divided into 9 groups. We employed three different arrays of MN electrodes were used (parallel, triangular, and circular), EP, IP with different volts (6, 9, 12 V), an infrared laser and an ultrasound (pulsed and continuous wave) as our two energy sources. Results revealed that parallel 6 V TDD@MN@IP@EP can be used as effective delivery system for G. macrophyllus from skin directly to target EAC cells. In addition MN@IP@EP@TDD G. macrophyllus is a potential SPS for SPDT treatment of EAC. With respect to normal control mice and as opposed to the EAC untreated control mice, MN@EP@IP TDD G. macrophyllus in the laser, ultrasound, and combination activated groups showed a significant increase in the antioxidant markers TAC level and the GST, GR, Catalase, and SOD activities, while decrease in lipid peroxidation oxidative stress parameter MDA levels. In addition significantly increased apoptotic genes expressions (p53, caspase (3, 9), Bax, and TNF alpha) and on the other hand decreased anti- apoptotic (Bcl-2) and angiogenic (VEGF) genes expressions. Moreover significantly ameliorate liver and kidney function decreasing ALT, AST, urea and creatinine respectively. Furthermore MN@IP@EP@TDD G. macrophyllus combined with SPDT was very effective at reducing the growth of tumors and even causing cell death according to microscopic H&E stain results. This process may be related to a sono- and/or photochemical activation mechanism. According to the findings, MN@IP@EP@TDD G. macrophyllus has a lot of potential as a novel, efficient delivery method that in combination with infrared laser and ultrasound activation SPDT demonstrated promising anticancer impact for treating cancer.

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

Microneedle Delivery Platform Integrated with Codelivery Nanoliposomes for Effective and Safe Androgenetic Alopecia Treatment

Although topical application of minoxidil is a widely used, FDA-approved therapy for androgenetic alopecia (AGA) treatment, it suffers from low bioavailability, the requirement for frequent long-term use, and side effects. With a similar structure as minoxidil, kopexil and kopyrrol are less toxic and have been commercialized, but show an inferior hair regeneration effect compared to minoxidil. Herein, we developed a hyaluronic acid (HA)-based dissolvable microneedles (MNs) delivery platform integrated with kopexil and kopyrrol coencapsulated nanoliposomes (KK-NLPs) to effectively and safely treat AGA. Facilitated by nanoliposomes and MNs, the encapsulated KK-NLPs performed efficient skin penetration and enhanced cellular internalization into human dermal papilla cells. Furthermore, within the target cells, the codelivered kopexil and kopyrrol show synergistic effects by orchestrating an upregulation in the expression of Ki67, β-catenin, vascular endothelial growth factor (VEGF), and CD31. These molecular responses collectively foster cell proliferation, migration, and antioxidative effects, thereby facilitating the expedited progression of hair follicles (HFs) into the anagen phase and promoting peripheral angiogenesis. Notably, the KK-NLPs-integrated MNs treatment group exhibits noteworthy enhanced hair regeneration in vivo, with identical or superior therapeutic effects at a much lower dosage than that of minoxidil. These results suggest the great potential of this kopexil and kopyrrol codelivery nanoliposomes-integrated MNs platform for AGA treatment in a safe and efficient way.

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.

Glucose-responsive insulin microneedle patches for long-acting delivery and release visualization

Limited drug loading and incomplete drug release are two major obstacles that traditional polymeric microneedles (MNs) have to overcome. For smart controlled-release MNs, since drug release duration is uncertain, a clear indication of the finish of drug release is also important for patient guidance on the timing of the next dose. In this study, MN with a triple structure of a glucose-responsive shell, loaded insulin powders and a colored propelling inner core (inspired by the mechanism of osmotic pump) was innovatively constructed. The MN patch could release insulin according to blood glucose levels (BGLs) and had excellent drug loading, more complete drug release, and good drug stability, which significantly prolonged the normoglycemic time. An approximately 0.3 cm2 patch has a hypoglycemic effect on diabetic mice for up to 24 h. Moreover, the fading of the inner core could indicate the release process of the loaded drug and can help to facilitate uninterrupted closed loop therapy for patients. The designed triple MN structure is also suitable, and can be used in the design of other smart MN drug delivery systems to further improve their drug loading capacity and simultaneously achieve more complete, smart controlled and visualized drug release.

Predictive modeling of skin permeability for molecules: Investigating FDA-approved drug permeability with various AI algorithms

The transdermal route of drug administration has gained popularity for its convenience and bypassing the first-pass metabolism. Accurate skin permeability prediction is crucial for successful transdermal drug delivery (TDD). In this study, we address this critical need to enhance TDD. A dataset comprising 441 records for 140 molecules with diverse LogKp values was characterized. The descriptor calculation yielded 145 relevant descriptors. Machine learning models, including MLR, RF, XGBoost, CatBoost, LGBM, and ANN, were employed for regression analysis. Notably, LGBM, XGBoost, and gradient boosting models outperformed others, demonstrating superior predictive accuracy. Key descriptors influencing skin permeability, such as hydrophobicity, hydrogen bond donors, hydrogen bond acceptors, and topological polar surface area, were identified and visualized. Cluster analysis applied to the FDA-approved drug dataset (2326 compounds) revealed four distinct clusters with significant differences in molecular characteristics. Predicted LogKp values for these clusters offered insights into the permeability variations among FDA-approved drugs. Furthermore, an investigation into skin permeability patterns across 83 classes of FDA-approved drugs based on the ATC code showcased significant differences, providing valuable information for drug development strategies. The study underscores the importance of accurate skin permeability prediction for TDD, emphasizing the superior performance of nonlinear machine learning models. The identified key descriptors and clusters contribute to a nuanced understanding of permeability characteristics among FDA-approved drugs. These findings offer actionable insights for drug design, formulation, and prioritization of molecules with optimum properties, potentially reducing reliance on costly experimental testing. Future research directions include offering promising applications in pharmaceutical research and formulation within the burgeoning field of computer-aided drug design.

Dandelion-derived vesicles-laden hydrogel dressings capable of neutralizing Staphylococcus aureus exotoxins for the care of invasive wounds

Delayed wound healing caused by bacterial infection remains a major challenge in clinical treatment. Exotoxins incorporated in bacterial extracellular vesicles play a key role as the disease-causing virulence factors. Safe and specific antivirulence agents are expected to be developed as an effective anti-bacterial infection strategy, instead of single antibiotic therapy. Plant-derived extracellular vesicle-like nanoparticles have emerged as promising therapeutic agents for skin diseases, but the elucidations of specific mechanisms of action and clinical transformation still need to be advanced. Here, dandelion-derived extracellular vesicle-like nanoparticles (TH-EVNs) are isolated and exert antivirulence activity through specifically binding to Staphylococcus aureus (S. aureus) exotoxins, thereby protecting the host cell from attack. The neutralization of TH-EVNs against exotoxins has considerable binding force and stability, showing complete detoxification effect in vivo. Then gelatin methacryloyl hydrogel is developed as TH-EVNs-loaded dressing for S. aureus exotoxin-invasive wounds. Hydrogel dressings demonstrate good physical and mechanical properties, thus achieving wound retention and controlled release of TH-EVNs, in addition to promoting cell proliferation and migration. In vivo results show accelerated re-epithelialization, promotion of collagen maturity and reduction of inflammation after treatment. Collectively, the developed TH-EVNs-laden hydrogel dressings provide a potential therapeutic approach for S. aureus exotoxin- associated trauma.

Nanotechnology strategies to address challenges in topical and cellular delivery of siRNAs in skin disease therapy

Gene therapy is one of the most advanced therapies in current medicine. In particular, interference RNA-based therapy by small interfering RNA (siRNA) has gained attention in recent years as it is a highly versatile, selective and specific therapy. In dermatological conditions, topical delivery of siRNA offers numerous therapeutic advantages, mainly by inhibiting the expression of target transcripts directly in the skin. However, crossing the stratum corneum and overcoming intracellular barriers is an inherent challenge. Substantial efforts by scientists have moved towards the use of multimodal and multifunctional nanoparticles to overcome these barriers and achieve greater bioavailability in their site of action, the cytoplasm. In this review the most innovative strategies based on nanoparticle and physical methods are presented, as well as the design principles and the main factors that contribute to the performance of these systems. This review also highlights the synergistic contributions of medicine, nanotechnology, and molecular biology to advancing translational research into siRNA-based therapeutics for skin diseases.

Evaluation of Antioxidant Activity and Treatment of Eczema by Berberine Hydrochloride-Loaded Liposomes-in-Gel

In this paper, berberine hydrochloride-loaded liposomes-in-gel were designed and developed to investigate their antioxidant properties and therapeutic effects on the eczema model of the mouse. Berberine hydrochloride-liposomes (BBH-L) as the nanoparticles were prepared by the thin-film hydration method and then dispersed BBH-L evenly in the gel matrix to prepare the berberine hydrochloride liposomes-gel (BBH-L-Gel) by the natural swelling method. Their antioxidant capacity was investigated by the free radical scavenging ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2 and the inhibition of lipid peroxides malondialdehyde (MDA). An eczema model was established, and the efficacy of the eczema treatment was preliminarily evaluated using ear swelling, the spleen index, and pathological sections as indicators. The results indicate that the entrapment efficiency of BBH-L prepared by the thin-film hydration method was 78.56% ± 0.7%, with a particle size of 155.4 ± 9.3 nm. For BBH-L-Gel, the viscosity and pH were 18.16 ± 6.34 m Pas and 7.32 ± 0.08, respectively. The cumulative release in the unit area of the in vitro transdermal study was 85.01 ± 4.53 μg/cm2. BBH-L-Gel had a good scavenging capacity on DPPH and H2O2, and it could effectively inhibit the production of hepatic lipid peroxides MDA in the concentration range of 0.4-2.0 mg/mL. The topical application of BBH-L-Gel could effectively alleviate eczema symptoms and reduce oxidative stress injury in mice. This study demonstrates that BBH-L-Gel has good skin permeability, excellent sustained release, and antioxidant capabilities. They can effectively alleviate the itching, inflammation, and allergic symptoms caused by eczema, providing a new strategy for clinical applications in eczema treatment.

E-Tattoos: Toward Functional but Imperceptible Interfacing with Human Skin

The human body continuously emits physiological and psychological information from head to toe. Wearable electronics capable of noninvasively and accurately digitizing this information without compromising user comfort or mobility have the potential to revolutionize telemedicine, mobile health, and both human-machine or human-metaverse interactions. However, state-of-the-art wearable electronics face limitations regarding wearability and functionality due to the mechanical incompatibility between conventional rigid, planar electronics and soft, curvy human skin surfaces. E-Tattoos, a unique type of wearable electronics, are defined by their ultrathin and skin-soft characteristics, which enable noninvasive and comfortable lamination on human skin surfaces without causing obstruction or even mechanical perception. This review article offers an exhaustive exploration of e-tattoos, accounting for their materials, structures, manufacturing processes, properties, functionalities, applications, and remaining challenges. We begin by summarizing the properties of human skin and their effects on signal transmission across the e-tattoo-skin interface. Following this is a discussion of the materials, structural designs, manufacturing, and skin attachment processes of e-tattoos. We classify e-tattoo functionalities into electrical, mechanical, optical, thermal, and chemical sensing, as well as wound healing and other treatments. After discussing energy harvesting and storage capabilities, we outline strategies for the system integration of wireless e-tattoos. In the end, we offer personal perspectives on the remaining challenges and future opportunities in the field.

[Rapamycin and HPPH Co-Loaded Nanodrug Delivered via Dissolvable Microneedles to Treat Port-Wine Stains]

Objective

Port-wine stains are a kind of dermatological disease of congenital capillary malformation. Based on the biological characteristics of port-wine stains and the advantages of microneedle transdermal administration, we intend to construct a nanodrug co-loaded with rapamycin (RPM), an anti-angiogenesis drug, and photochlor (HPPH), a photosensitizer, and integrate the nanodrug with dissolvable microneedles (MN) to achieve anti-angiogenesis and photodynamic combination therapy for port-wine stains.

Methods

First, RPM and HPPH co-loaded nanoparticles (RPM-HPPH NP) were prepared by the emulsification solvent-volatilization method, and its ability to generate reactive oxygen species (ROS) was investigated under 660 nm laser irradiation. Mouse hemangioendothelioma endothelial cells (EOMA) were used as the subjects of the study. The cellular uptake behaviors were examined by fluorescence microscopy and flow cytometry. The cytotoxicity effects of RPM-HPPH NP with or without 660 nm laser irradiation on EOMA cells were examined by MTT assays (with free RPM serving as the control). Then, hyaluronic acid (HA) dissolvable microneedles loaded with RPM-HPPH NP (RPM-HPPH NP@HA MN) were obtained by compounding the nanodrug with HA dissolvable microneedle system through the molding method. The morphological characteristics and mechanical properties of RPM-HPPH NP@HA MN were investigated by scanning electron microscope and electronic universal testing machine. The penetration ability of RPM-HPPH NP@HA MN on the skin of nude mice was evaluated by trypan blue staining and H&E staining experiment.

Results

The RPM-HPPH NP prepared in the study had a particle size of 150 nm and generated large amounts of ROS under laser irradiation. At the cellular level, RPM-HPPH NP was taken up by EOMA cells in a time-dependent manner. The cytotoxicity of RPM-HPPH NP was higher than that of free RPM with or without laser irradiation. Under laser irradiation, RPM-HPPH NP exhibited stronger cytotoxic effects and the difference was statistically significant (P<0.05). The height of the needle tip of RPM-HPPH NP@HA MN was 600 µm and the mechanical property of a single needle was 0.75048 N. Trypan blue staining and HE staining showed that pressing on the microneedles could produce pores on the skin surface and penetration of the stratum corneum.

Conclusion

RPM-HPPH NP@HA MN can deliver RPM-HPPH NP percutaneously to the lesion tissue and realize the synergistic treatment of port-wine stains with anti-angiogenic therapy and photodynamic therapy, providing a new strategy for the construction of nanodrug-loaded microneedle delivery system and the clinical treatment of port-wine stains.

Incorporating surfactants into PCL microneedles for sustained release of a hydrophilic model drug

Polymeric microneedles (MNs) are widely used for sustained drug release due to their distinct advantages over other types of MNs. Poly-ε-caprolactone (PCL) stands out as a biodegradable and biocompatible hydrophobic polymer commonly employed in drug delivery applications. This study explores the impact of surfactants on the encapsulation and release rate of a model hydrophilic drug, minoxidil (MXD), from PCL MNs. Three nonionic surfactants, Tween 80, Span 60, and polyethylene glycol (PEG), were integrated into PCL MNs at varying concentrations. Compared to the other types of surfactants, PEG-containing PCL MNs exhibit enhanced insertion capabilities into a skin-simulant parafilm model and increased mechanical strength, suggesting facile penetration into the stratum corneum. Furthermore, MXD-PEG MNs show the highest encapsulation efficiency and are further characterized using FTIR, DSC and XRD. Their mechanical strength against different static forces was measured. The MNs exhibit a sustained release pattern over 20 days. Eventually, MXD-PEG MNs were subjected to penetration testing using chicken skin and required minimal insertion forces with no observed MN failure during experimentation even after compression with the maximum force applied (32 N per patch). Taken together, the present work demonstrates the feasibility of incorporating nonionic surfactants like PEG into the tips of hydrophobic PCL MNs for sustained delivery of a model hydrophilic drug. This formulation strategy can be used to improve patient compliance by allowing self-administration and achieving prolonged drug release.

Effect of ion pair strategy on transdermal delivery of guanfacine: Which factor dominates drug permeation?

Ion pair is an effective chemical approach to promoting drug transdermal permeation, and the traditional interpretation for its enhanced permeation effect is mainly attributed to counterions altering the physicochemical properties of the drug (lipophilicity, melting point, etc.). In this work, guanfacine (GFC), a non-stimulant for anti-attention deficit and hyperactivity disorder (ADHD), was used as a model drug, and several organic or inorganic acids were designed thereby successfully constructing ion pairs. The transdermal permeation ability of ion pairs through isolated porcine skin was observed and ranked as follows: guanfacine caprylate (GFC-CA) > GFC > guanfacine laurate (GFC-LA) > guanfacine fumarate (GFC-FA) > guanfacine hydrochloride (GFC-HA) > guanfacine palmitate (GFC-PA). The effect of key physicochemical properties (octanol-water partition coefficient, molecular volume, melting point) on the transdermal permeation rate of the model drug was analyzed in detail. In addition, GFC-CA was observed to alter the lipid structure of the skin, suggesting the traditional explanation of the action of ion pair may be inadequate and underrated, and ion pair may also enhance permeation by disrupting skin structure. The intriguing phenomenon is expected to provide a novel approach to achieving precise transdermal drug delivery.

A landscape of recent advances in lipid nanoparticles and their translational potential for the treatment of solid tumors

Lipid nanoparticles (LNPs) are biocompatible drug delivery systems that have found numerous applications in medicine. Their versatile nature enables the encapsulation and targeting of various types of medically relevant molecular cargo, including oligonucleotides, proteins, and small molecules for the treatment of diseases, such as cancer. Cancers that form solid tumors are particularly relevant for LNP-based therapeutics due to the enhanced permeation and retention effect that allows nanoparticles to accumulate within the tumor tissue. Additionally, LNPs can be formulated for both locoregional and systemic delivery depending on the tumor type and stage. To date, LNPs have been used extensively in the clinic to reduce systemic toxicity and improve outcomes in cancer patients by encapsulating chemotherapeutic drugs. Next-generation lipid nanoparticles are currently being developed to expand their use in gene therapy and immunotherapy, as well as to enable the co-encapsulation of multiple drugs in a single system. Other developments include the design of targeted LNPs to specific cells and tissues, and triggerable release systems to control cargo delivery at the tumor site. This review paper highlights recent developments in LNP drug delivery formulations and focuses on the treatment of solid tumors, while also discussing some of their current translational limitations and potential opportunities in the field.

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.

Cutaneous Pharmacokinetics of Topically Applied Novel Dermatological Formulations

Novel formulations are developed for dermatological applications to address a wide range of patient needs and therapeutic challenges. By pushing the limits of pharmaceutical technology, these formulations strive to provide safer, more effective, and patient-friendly solutions for dermatological concerns, ultimately improving the overall quality of dermatological care. The article explores the different types of novel dermatological formulations, including nanocarriers, transdermal patches, microsponges, and microneedles, and the techniques involved in the cutaneous pharmacokinetics of these innovative formulations. Furthermore, the significance of knowing cutaneous pharmacokinetics and the difficulties faced during pharmacokinetic assessment have been emphasized. The article examines all the methods employed for the pharmacokinetic evaluation of novel dermatological formulations. In addition to a concise overview of earlier techniques, discussions on novel methodologies, including tape stripping, in vitro permeation testing, cutaneous microdialysis, confocal Raman microscopy, and matrix-assisted laser desorption/ionization mass spectrometry have been conducted. Emerging technologies like the use of microfluidic devices for skin absorption studies and computational models for predicting drug pharmacokinetics have also been discussed. This article serves as a valuable resource for researchers, scientists, and pharmaceutical professionals determined to enhance the development and understanding of novel dermatological drug products and the complex dynamics of cutaneous pharmacokinetics.

Delivery Strategies for Colchicine as a Critical Dose Drug: Reducing Toxicity and Enhancing Efficacy

Colchicine (COL), a widely used natural drug, has potent anti-inflammatory effects; however, as a narrow therapeutic index drug, its clinical application is limited by its serious gastrointestinal adverse effects, and only oral formulations are currently marketed worldwide. Recent studies have shown that transdermal, injection, and oral drug delivery are the three main delivery strategies for COL. This article elaborates on the research progress of different delivery strategies in terms of toxicity reduction and efficacy enhancement, depicting that the transdermal drug delivery route can avoid the first-pass effect and the traumatic pain associated with the oral and injection routes, respectively. Therefore, such a dosage form holds a significant promise that requires the development of further research to investigate effective COL delivery formulations. In addition, the permeation-promoting technologies utilized for transdermal drug delivery systems are briefly discussed. This article is expected to provide scientific ideas and theoretical guidance for future research and the exploration of COL delivery strategies.

Liposome Encapsulation of the Palmitoyl-KTTKS Peptide: Structural and Functional Characterization

In this study, the amphiphilic N-palmitoyl-KTTKS peptide was integrated in the bilayer of egg-derived phosphatidylcholine (PC) vesicles using two different preparation methods, namely thin-film evaporation (TLE) and reverse-phase evaporation (REV). Both the REV and TLE methods allowed for the formation of homogeneous liposome dispersions (PdI < 0.20) with mean hydrodynamic diameters of <100 nm and <200 nm, respectively, a net negative surface charge and a percentage of structured phospholipids higher than 90%. The inclusion of the amphiphilic N-palmitoyl-KTTKS peptide within phospholipid-based vesicles could improve peptide stability and skin delivery. Therefore, the obtained liposomes were evaluated via experiments assessing the synthesis of collagen and the ECM in 3T3-NIH fibroblasts. The obtained results showed that, when delivered with PC liposomes, pal-KTTKS stimulated collagen production more than free pentapeptide and 1 mM ascorbic acid, used as a positive control.

Chiral Supramolecular Hydrogel Enhanced Transdermal Delivery of Sodium Aescinate to Modulate M1 Macrophage Polarization Against Lymphedema

Sodium aescinate (SA) shows great potential for treating lymphedema since it can regulate the expression of cytokines in M1 macrophages, however, it is commonly administered intravenously in clinical practice and often accompanied by severe toxic side effects and short metabolic cycles. Herein, SA-loaded chiral supramolecular hydrogels are prepared to prove the curative effects of SA on lymphedema and enhance its safety and transdermal transmission efficiency. In vitro studies demonstrate that SA- loaded chiral supramolecular hydrogels can modulate local immune responses by inhibiting M1 macrophage polarization. Typically, these chiral hydrogels can significantly increase the permeability of SA with good biocompatibility due to the high enantioselectivity between chiral gelators and stratum corneum and L-type hydrogels are found to have preferable drug penetration over D-type hydrogels. In vivo studies show that topical delivery of SA via chiral hydrogels results in dramatic therapeutic effects on lymphedema. Specifically, it can downregulate the level of inflammatory cytokines, reduce the development of fibrosis, and promote the regeneration of lymphatic vessels. This study initiates the use of SA for lymphedema treatment and for the creation of an effective chiral biological platform for improved topical administration.

Impact of Formulation and Microneedle Length on Transdermal Metronidazole Permeation through Microneedle-Treated Skin

OBJECTIVE

This study aimed to determine the impact of formulation (gel vs cream) and microneedle characteristics (length, number) on permeation of metronidazole through excised microneedle-treated skin. The long-term goal is to apply these results towards a pharmacokinetic study in human subjects with diverse skin types, using in vitro flux data to determine dosing conditions and ultimately establish in vitro-in vivo correlations.

METHODS

Metronidazole release from 0.75% gel and cream was quantified with flow-through diffusion cells, using a cellulose membrane. Excised porcine skin was treated with stainless steel microneedles (500 or 800 μm length), to create 50 or 100 micropores. Metronidazole gel or cream was applied to microneedle-treated skin and replaced every 48 h for up to 7 days. Metronidazole permeation was quantified using HPLC. Intact skin (no microneedle treatment) served as controls.

RESULTS

Metronidazole release was faster from the gel vs cream. At 7 days there was no difference between gel vs cream in total metronidazole permeated through intact skin. For both formulations, metronidazole permeation was significantly higher (vs intact skin) following microneedle application, regardless of microneedle length or micropore number. Increasing microneedle length and micropore number enhanced MTZ permeation multiple fold for both gel and cream. The greatest enhancement in total permeation for both formulations was achieved with the 800 μm MN, 100 micropore condition.

CONCLUSIONS

Formulation and microneedle conditions both impacted metronidazole permeation. These data will be used to estimate in vivo serum concentrations after applying metronidazole to microneedle-treated skin in humans.

Improvement of transdermal absorption rate by nonthermal biocompatible atmospheric pressure plasma

Nonthermal biocompatible plasma (NBP) is a promising option for improving medication absorption into the human skin. Currently, most plasma devices for cosmetics employ a floating-electrode plasma source for treating the skin. Human skin serves as the ground electrode in the floating-electrode plasma discharge, and discharge occurs between the skin and electrodes of the device. In this in vitro study, we aimed to evaluate the effect of NBP on the skin permeation of niacinamide. We have quantified the transdermal absorption rates of niacinamide in both untreated skin and skin treated with NBP for a duration of 10 s. The absorption of niacinamide for both without and with NBP treatment was observed until 12 h incubation time. Without plasma treatment, the human skin exhibited stable and low transdermal absorption of niacinamide up to 12 h. However, the NBP treatment significantly increased the transdermal absorption of niacinamide from 0.5 h to 6 h and continuously increased skin penetration over a duration of more than 12 h incubation period. The obtained results suggest that NBP-treated human skin showed a 60-fold higher penetration rate than non-treated skin. The increased penetration rate of niacinamide can be mainly attributed to plasmaporation subsequent to NBP treatment. The findings of this study demonstrate that NBP treatment results in remarkable skin permeability, making it a promising candidate for both cosmetic and pharmaceutical delivery applications.

Model-Informed Drug Development: In Silico Assessment of Drug Bioperformance following Oral and Percutaneous Administration

The pharmaceutical industry has faced significant changes in recent years, primarily influenced by regulatory standards, market competition, and the need to accelerate drug development. Model-informed drug development (MIDD) leverages quantitative computational models to facilitate decision-making processes. This approach sheds light on the complex interplay between the influence of a drug's performance and the resulting clinical outcomes. This comprehensive review aims to explain the mechanisms that control the dissolution and/or release of drugs and their subsequent permeation through biological membranes. Furthermore, the importance of simulating these processes through a variety of in silico models is emphasized. Advanced compartmental absorption models provide an analytical framework to understand the kinetics of transit, dissolution, and absorption associated with orally administered drugs. In contrast, for topical and transdermal drug delivery systems, the prediction of drug permeation is predominantly based on quantitative structure-permeation relationships and molecular dynamics simulations. This review describes a variety of modeling strategies, ranging from mechanistic to empirical equations, and highlights the growing importance of state-of-the-art tools such as artificial intelligence, as well as advanced imaging and spectroscopic techniques.

Topical Skin Application of Small-Molecule Antiplatelet Agent against Pressure Injury in Rat Models

Due to prolonged forced positioning, the incidence of intraoperative pressure injuries is high. This study aimed to explore the impact of small-molecule antiplatelet drugs on pressure injuries by locally applying them before an injury occurs. In the first part of this study, water-soluble tracers with different molecular weights were applied to normal and early-stage pressure-injured skin. Through digital cameras, spectrophotometers, and histological observations, the penetration of tracers into the epidermis was clarified. In the second part of this study, a water-soluble antiplatelet drug called Trapidil (molecular weight = 205 Da) was applied to the left side of the back of a rat before, during, and after compression, and the contralateral side served as a non-intervention control group. The differences in pressure injuries between the two groups were observed through a digital camera, an ultraviolet camera, and temperature measurement, and skin circulation and perfusion were assessed via an intravenous injection of Evans Blue. The first part of this study found that water-soluble tracers did not easily penetrate normal skin but could more easily penetrate pressure-damaged skin. The smaller the molecular weight of the tracer, the easier it penetrated the skin. Therefore, in the next step of research, water-soluble drugs with smaller molecular weights should be selected. The second part of this study found that, compared with the control group, the occurrence rates and areas of ulcers were lower, the gray value was higher, and the skin temperature was lower in the Trapidil group (p < 0.05). After the intravenous Evans Blue injection, skin circulation and perfusion in the Trapidil group were found to be better. In conclusion, this study found that the topical skin application of a small-molecule antiplatelet agent may have significant effects against pressure injuries by improving post-decompression ischemia, providing new insights into the prevention and treatment of intraoperative pressure injuries.

Unraveling the Molecular Mechanisms of Alcohol-Mediated Skin Permeation Enhancement: Insights from Molecular Dynamics Simulations

The application of alcohols as permeation enhancers in pharmaceutical and cosmetic formulations has attracted considerable attention, owing to their skin permeation-enhancing effect. Nonetheless, the elucidation of the fundamental mechanisms underlying the skin permeation-enhancing effect remains elusive. In this study, molecular dynamics (MD) simulations were employed to investigate the effect of 1,2-propanediol (1,2-PDO), 1,2-butanediol (1,2-BDO), and ethanol (EtOH) on the stratum corneum (SC) model membrane. The results showed that the effect of alcohols on the SC model membrane displayed a concentration-dependent nature. The alcohols can interact with SC lipids and exhibit a remarkable ability to selectively extract free fatty acid (FFA) molecules from the SC model membrane and make the SC looser. Meanwhile, 1,2-BDO and EtOH can penetrate into SC lipid bilayers at higher concentrations, leading to the formation of continuous hydrophilic defects in SC. The FFA extraction and the formation of continuous hydrophilic defects induced ceramide (CER) tail chains to become more disordered and fluid and also weakened the hydrogen bonding (H-bonding) network among SC lipids. Both the FFA extraction and the continuous hydrophilic defect formation endowed alcohols with the permeation-enhancing effect. The constrained simulations revealed that the free energy barriers decreased for the permeation of the hydrophilic model molecule (COL) across the SC model membranes containing alcohols, particularly for 1,2-BDO and EtOH. The possible permeation-enhancing mechanisms of alcohols were proposed correspondingly. This work not only provided a deep understanding of the transdermal permeation-enhancing behavior of alcohols at the molecular level but also provided necessary reference information for designing effective transdermal drug delivery systems in applications.

A universal powder-laden crosslinked chitosan microneedle patch for high-dose controllable drug delivery

In this study, we constructed a novel powder-laden core-shell crosslinked chitosan microneedle patch for high-dose and controllable delivery of various drugs, including both macromolecular biological drugs and small-molecule chemical drugs. Direct loading of drug powders greatly improved drug loading capacity and minimized degradation. The results of the in vitro drug release study suggested that the release behaviors of the most tested drugs (both macromolecular drugs and small-molecule drugs) can be tuned by adjusting the crosslink density of the microneedle shell to achieve either rapid or sustained release of the loaded drug. The in vivo hypoglycemic efficacy test in streptozotocin-induced diabetic mice further proved that the onset and duration of the insulin-laden patch can be customized by adjusting the crosslink density. Furthermore, a combination of microneedle patches with different crosslink densities not only rapidly reduced blood glucose levels to normoglycemic levels (within 1 h) but also maintained normoglycemia for up to 36 h. The insulin loaded in the patch also showed good stability during storage at 40 °C for 6 months. Our results suggest that this powder-laden patch represents a strong candidate for addressing the multiple challenges in the preparation and application of polymeric microneedles and shows promise in clinical applications.

[Development of Transdermal Formulation Based on Nanotechnology and Elucidation of Its Drug Delivery Pathways]

Transdermal drug delivery is a formulation in which the drug is absorbed through the skin for systemic action. Its advantages include avoidance of first-pass effects, sustained drug supply, and ease of administration and discontinuation. Drugs administered transdermally transfer into the blood circulation through the stratum corneum, epidermis, and dermis. The stratum corneum on the skin surface plays a barrier function in skin absorption. Therefore, developing of transdermal drug delivery systems requires innovations that overcome the barrier function of the stratum corneum and improve skin permeation. This review examines the usefulness of transdermal formulations based on solid nanoparticles using raloxifene. Milled raloxifene was gelled with (mRal-NPs) or without menthol (Ral-NPs) using Carbopol. The drug release and transdermal penetration were measured using a Franz diffusion cell, and the therapeutic evaluation of osteoporosis was determined in an ovariectomized rat model. Although the raloxifene released from Ral-NPs remained in the nanoparticle state, the skin penetration of raloxifene nanoparticles was prevented by the stratum corneum in rat. The inclusion of menthol in the formulation attenuated the barrier function of the stratum corneum and permitted raloxifene nanoparticles to penetrate through the skin. Moreover, macropinocytosis relates to the formulation's skin penetration, including menthol (mRal-NPs). Applying mRal-NPs attenuated the decreases in calcium level and stiffness of bones of ovariectomized rats. This information can support future studies aimed at designing novel transdermal formulations.

An Ultraswelling Microneedle Device for Facile and Efficient Drug Loading and Transdermal Delivery

The advancement and extensive demand for transdermal therapies can benefit from a safe, and efficient and user-friendly transdermal technology with broad applicability in delivering various hydrophilic drugs. Here the design and proof of concept applications of an ultraswelling microneedle device that enables the facile and efficient loading and transdermal delivery of hydrophilic drugs with different molecular weights is reported. The device consists of a super-hydrophilic hydrogel microneedle array and a resin base substrate. Using a special micromolding technique that involves hydrated crosslinking and cryogenic-demolding, the microneedle part displays a rapid swelling ratio of ≈3800%, enabling the loading of drugs up to 500 kDa in molecular weight. The drug loading process using the device just involves incubating the microneedle part in a drug solution for 1 min, followed by 15 min of drying. The microneedles can easily penetrate the skin under press and detach from the base substrate under shear, thereby releasing the payload. Administration of desired therapeutic agents using the device outperformed conventional administration methods in mitigating psoriasis and eliciting immunity. This biocompatible device, capable of withstanding ethylene oxide sterilization, can enhance the efficacy and accessibility of transdermal therapies in research institutes, hospitals, and even home settings.

Exploring the potential of the nano-based sunscreens and antioxidants for preventing and treating skin photoaging

Excessive exposure to sunlight, especially UV irradiation, causes skin photodamage. Sunscreens, such as TiO2 and ZnO, can potentially prevent UV via scattering, reflection, and absorption. Topical antioxidants are another means of skin photoprotection. Developing nanoparticles for sunscreens and antioxidants is recommended for photoaging prevention and treatment as it can improve uncomfortable skin appearance, stability, penetration, and safety. This study reviewed the effects of nano-sized sunscreens and antioxidants on skin photoprevention by examining published studies and articles from PubMed, Scopus, and Google Scholar, which explore the topics of skin photoaging, skin senescence, UV radiation, keratinocyte, dermal fibroblast, sunscreen, antioxidant, and nanoparticle. The researchers of this study also summarized the nano-based UV filters and therapeutics for mitigating skin photoaging. The skin photodamage mechanisms are presented, followed by the introduction of current skin photoaging treatment. The different nanoparticle types used for topical delivery were also explored in this study. This is followed by the mechanisms of how nanoparticles improve the UV filters and antioxidant performance. Lastly, recent investigations were reviewed on nanoparticulate sunscreens and antioxidants in skin photoaging management. Sunscreens and antioxidants for topical application have different concepts. Topical antioxidants are ideal for permeating into the skin to exhibit free radical scavenging activity, while UV filters are prescribed to remain on the skin surface without absorption to exert the UV-blocking effect without causing toxicity. The nanoparticle design strategy for meeting the different needs of sunscreens and antioxidants is also explored in this study. Although the benefits of using nanoparticles for alleviating photodamage are well-established, more animal-based and clinical studies are necessary.

Hair and Nail-On-Chip for Bioinspired Microfluidic Device Fabrication and Biomarker Detection

The advent of biosensors has tremendously increased our potential of identifying and solving important problems in various domains, ranging from food safety and environmental analysis, to healthcare and medicine. However, one of the most prominent drawbacks of these technologies, especially in the biomedical field, is to employ conventional samples, such as blood, urine, tissue extracts and other body fluids for analysis, which suffer from the drawbacks of invasiveness, discomfort, and high costs encountered in transportation and storage, thereby hindering these products to be applied for point-of-care testing that has garnered substantial attention in recent years. Therefore, through this review, we emphasize for the first time, the applications of switching over to noninvasive sampling techniques involving hair and nails that not only circumvent most of the aforementioned limitations, but also serve as interesting alternatives in understanding the human physiology involving minimal costs, equipment and human interference when combined with rapidly advancing technologies, such as microfluidics and organ-on-a-chip to achieve miniaturization on an unprecedented scale. The coalescence between these two fields has not only led to the fabrication of novel microdevices involving hair and nails, but also function as robust biosensors for the detection of biomarkers, chemicals, metabolites and nucleic acids through noninvasive sampling. Finally, we have also elucidated a plethora of futuristic innovations that could be incorporated in such devices, such as expanding their applications in nail and hair-based drug delivery, their potential in serving as next-generation wearable sensors and integrating these devices with machine-learning for enhanced automation and decentralization.

Designed Fabrication of Phloretin-Loaded Propylene Glycol Binary Ethosomes: Stability, Skin Permeability and Antioxidant Activity

Binary ethosome vesicles have been developed as flexible lipid vesicles for the enhanced physicochemical stability and skin delivery of drugs. This work aimed to prepare phloretin-loaded propylene glycol ethosomes (PHL-PGEs) to improve their stability, skin permeability and antioxidant activity. PHL-PGEs were prepared via the ethanol injection method and optimized using different weight ratios of ethanol to propylene glycol (PG). When the ethanol/PG mass ratio changed from 10:0 to 0:10, the encapsulation efficiency and stability of ethosomes increased. At a PHL concentration of 1mg/mL, the EE% was 89.42 ± 2.42 and the DL% was 4.21 ± 0.04, which exhibited their highest values. The encapsulation of the PHL in the PHL-PGEs was strengthened via XRD analysis and FTIR analysis. The results of the in vitro percutaneous permeability test demonstrated that the combined use of ethanol and PG exhibited a notable enhancement in skin permeability, and the skin retention of PHL-PGEs was 1.06 times that of PHL-ethosomes (PHL-Es) and 2.24 times that of the PHL solution. An in vitro antioxidant activity study indicated that solubility and antioxidant activity was potentiated via the nanoencapsulation of phloretin. Therefore, these results confirm the potential of this nanocarrier to enhance physicochemical stability, skin permeability and antioxidant activity.

Evaluation of Dose-Response Relationship of Permeation Enhancer Isopropyl Myristate Release on Drug Release: Release Enhancement Efficiency and Molecular Mechanism

The objective of this study is to investigate the dose-response relationship between various concentrations of permeation enhancers (PEs) and their ability to enhance drug release from a polymer matrix, utilizing an innovative parameter known as release enhancement efficiency (K). Additionally, the molecular mechanism underlying dynamic enhancement was also examined. Isopropyl myristate (IPM) was used as model enhancer and zolmitriptan (ZOL) was used as model drug to investigate dose-effect relationship in pressure sensitive adhesives (PSA). The release behavior of the PEs was determined by LC-MS/MS and verified by confocal laser scanning microscopy (CLSM). The enhancing effect of the PE on ZOL release was evaluated through in vitro release experiments and further validated by pharmacokinetics study. And the molecular mechanism was characterized with thermal analysis (DSC), Fourier transform infrared spectroscopy (FT-IR) and molecular dynamics simulation. K was 0.156, 0.286 and 0.279 at 3%, 6% and 9% IPM concentrations, indicating that the enhancement efficiency reached the maximum when the 6% IPM was applied. According to the mechanism research results, the fluidity of PSA increased linearly with the increase of IPM concentrations, but the interaction between IPM and ZOL reached its strongest point at 6%. In summary, the increase of K value (from 0 to 6% IPM content) was caused by the synergy of increased mobility of PSA and interaction (dipole-dipole and hydrogen-bond) among three components, and when the above two actions were in antagonistic, K no longer increased (6-9% IPM content).

Toward a Platform for the Treatment of Burns: An Assessment of Nanoemulsions vs. Nanostructured Lipid Carriers Loaded with Curcumin

Curcumin is a highly promising substance for treating burns, owing to its anti-inflammatory, antioxidant, antimicrobial, and wound-healing properties. However, its therapeutic use is restricted due to its hydrophobic nature and low bioavailability. This study was conducted to address these limitations; it developed and tested two types of lipid nanocarriers, namely nanoemulsions (NE-CUR) and nanostructured lipid carriers (NLC-CUR) loaded with curcumin, and aimed to identify the most suitable nanocarrier for skin burn treatment. The study evaluated various parameters, including physicochemical characteristics, stability, encapsulation efficiency, release, skin permeation, retention, cell viability, and antimicrobial activity. The results showed that both nanocarriers showed adequate size (~200 nm), polydispersity index (~0.25), and zeta potential (~>-20 mV). They also showed good encapsulation efficiency (>90%) and remained stable for 120 days at different temperatures. In the release test, NE-CUR and NCL-CUR released 57.14% and 51.64% of curcumin, respectively, in 72 h. NE-CUR demonstrated better cutaneous permeation/retention in intact or scalded skin epidermis and dermis than NLC-CUR. The cell viability test showed no toxicity after treatment with NE-CUR and NLC-CUR up to 125 μg/mL. Regarding microbial activity assays, free curcumin has activity against P. aeruginosa, reducing bacterial growth by 75% in 3 h. NE-CUR inhibited bacterial growth by 65% after 24 h, and the association with gentamicin had favorable results, while NLC-CUR showed a lower inhibition. The results demonstrated that NE-CUR is probably the most promising nanocarrier for treating burns.

Smartphone-based iontophoresis transdermal drug delivery system for cancer treatment

Cancer is a leading cause of the death worldwide. However, the conventional cancer therapy still suffers from several limitations, such as systemic side effects, poor efficacy, and patient compliance due to limited accessibility to the tumor site. To address these issues, the localized drug delivery system has emerged as a promising approach. In this study, we developed an iontophoresis-based transdermal drug delivery system (TDDS) controlled by a smartphone application for cancer treatment. Iontophoresis, a low-intensity electric current-based TDDS, enhances drug permeation across the skin to provide potential for localized drug delivery and minimize systemic side effects. The fundamental mechanism of our system was modeled using finite element analysis and its performance was corroborated through the flow-through skin permeation tests using a plastic-based microfluidic chip. The results of in vitro cell experiments and skin deposition tests successfully demonstrated that our smartphone-controlled iontophoresis system significantly enhanced the drug permeation for cancer treatment. Therefore, this hand-held smartphone-based iontophoresis TDDS could be a powerful tool for self-administrated anticancer drug delivery applications.

Universal Strategy of Efficient Intracellular Macromolecule Directional Delivery Using Photothermal Pump Patch

The development of a highly efficient, nondestructive, and in vitro/vivo-applicable universal delivery strategy of therapeutic macromolecules into desired cells and tissues is very challenging. Photothermal methods have advantages in intracellular delivery, particularly in in vivo manipulation. However, the inability of directional transmission of exogenous molecules limits their delivery efficiency. Here, a photothermal pump (PTP) patch with numerous "exogenous molecular reservoirs" is reported. Under a laser, the cell membrane ruptures, while "exogenous molecular reservoirs" shrink, resulting in a directional exogenous molecule delivery into cells for a high-efficient intracellular delivery. The PTP patches are considered a universal structure for a highly efficient, nondestructive, and in-vitro/vivo-applicable intracellular macromolecule delivery. Under in vivo transdermal intracellular delivery conditions, the target genes are efficiently and noninvasively delivered into epidermal and dermal cells through the PTP patch and exosomes produced by the epidermal cells, respectively. The PTP patch provides a new strategy for a high-efficiency, nondestructive, and in-vitro/vivo-applicable macromolecule delivery.

Polyvinyl-alcohol, chitosan and graphene-oxide composed conductive hydrogel for electrically controlled fluorescein sodium transdermal release

Accurate and controlled release of drug molecules is crucial for transdermal drug delivery. Electricity, as an adjustable parameter, offers the potential for precise and controllable drug delivery. However, challenges exist in selecting the appropriate drug carrier, electrical parameters, and release model to achieve controlled electronic drug release. To overcome these challenges, this study designed a functional hydrogel using polyvinyl alcohol, chitosan, and graphene oxide as components that can conduct electricity, and constructed a drug transdermal release model using fluorescein sodium salt with proper electrical parameters. The results demonstrated that the hydrogel system exhibited low cytotoxicity, good conductivity, and desirable drug delivery characteristics. The study also integrated the effects of drug release and tissue repair promotion under electrical stimulation. Cell growth was enhanced under low voltage direct current pulses, promoting cell migration and the release of VEGF and FGF. Furthermore, the permeability of fluorescein sodium salt in the hydrogel increased with direct current stimulation. These findings suggest that the carbohydrate polymers hydrogel could serve as a drug carrier for controlled release, and electrical stimulation offers new possibilities for functional drug delivery and transdermal therapy.