Recent advances in polymeric transdermal drug delivery systems

Long-acting transdermal drug delivery formulations: Current developments and innovative pharmaceutical approaches

Transdermal administration remains an active research and development area as an alternative route for long-acting drug delivery. It avoids major drawbacks of conventional oral (gastrointestinal side effects, low drug bioavailability, and need for multiple dosing) or parenteral routes (invasiveness, pain, and psychological stress and bio-hazardous waste generated from needles), thereby increasing patient appeal and compliance. This review focuses on the current state of long-acting transdermal drug delivery, including adhesive patches, microneedles, and molecularly imprinted polymeric systems. Each subsection describes an approach including key considerations in formulation development, design, and process parameters with schematics. An overview of commercially available conventional (adhesive) patches for long-acting drug delivery (longer than 24 h), the reservoir- and matrix-type systems under preclinical evaluation, as well as the advanced transdermal formulations, such as the core-shell, nanoformulations-incorporated and stimuli-responsive microneedles, and 3D-printed and molecularly imprinted polymers that are in development, is also provided. Finally, we elaborated on translational aspects, challenges in patch formulation development, and future directions for the clinical advancement of new long-acting transdermal products.

Triggerable Patches for Medical Applications

Medical patches have garnered increasing attention in recent decades for several diagnostic and therapeutic applications. Advancements in material science, manufacturing technologies, and bioengineering have significantly widened their functionalities, rendering them highly versatile platforms for wearable and implantable applications. Of particular interest are triggerable patches designed for drug delivery and tissue regeneration purposes, whose action can be controlled by an external signal. Stimuli-responsive patches are particularly appealing as they may enable a high level of temporal and spatial control over the therapy, allowing high therapeutic precision and the possibility to adjust the treatment according to specific clinical and personal needs. This review aims to provide a comprehensive overview of the existing extensive literature on triggerable patches, emphasizing their potential for diverse applications and highlighting the strengths and weaknesses of different triggering stimuli. Additionally, the current open challenges related to the design and use of efficient triggerable patches, such as tuning their mechanical and adhesive properties, ensuring an acceptable trade-off between smartness and biocompatibility, endowing them with portability and autonomy, accurately controlling their responsiveness to the triggering stimulus and maximizing their therapeutic efficacy, are reviewed.

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

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.

Translation from Preclinical Research to Clinical Trials: Transdermal Drug Delivery for Neurodegenerative and Mental Disorders

Neurodegenerative diseases (NDs), particularly dementia, provide significant problems to worldwide healthcare systems. The development of therapeutic materials for various diseases has a severe challenge in the form of the blood-brain barrier (BBB). Transdermal treatment has recently garnered widespread favor as an alternative method of delivering active chemicals to the brain. This approach has several advantages, including low invasiveness, self-administration, avoidance of first-pass metabolism, preservation of steady plasma concentrations, regulated release, safety, efficacy, and better patient compliance. Topics include the transdermal method for therapeutic NDs, their classification, and the mechanisms that allow the medicine to enter the bloodstream through the skin. The paper also discusses the obstacles and potential outcomes of transdermal therapy, emphasizing the benefits and drawbacks of different approaches.

Accurate Spatio-Temporal Delivery of Nitric Oxide Facilitates the Programmable Repair of Avascular Dense Connective Tissues Injury

Avascular dense connective tissues (e.g., the annulus fibrosus (AF) rupture, the meniscus tear, and tendons and ligaments injury) repair remains a challenge due to the "biological barrier" that hinders traditional drug permeation and limits self-healing of the injured tissue. Here, accurate delivery of nitric oxide (NO) to penetrate the "AF biological barrier" is achieved thereby enabling programmable AF repair. NO-loaded BioMOFs are synthesized and mixed in a modified polyvinyl alcohol and PCL-composited electrospun fiber membrane with excellent reactive oxygen species-responsive capability (LN@PM). The results show that LN@PM could respond to the high oxidative stress environment at the injured tissue and realize continuous and substantial NO release. Based on low molecular weight and lipophilicity, NO could penetrate through the "biological barrier" for accurate AF drug delivery. Moreover, the dynamic characteristics of the LN@PM reaction can be matched with the pathological microenvironment to initiate programmable tissue repair including sequential remodeling microenvironment, reprogramming the immune environment, and finally promoting tissue regeneration. This tailored programmable treatment strategy that matches the pathological repair process significantly repairs AF, ultimately alleviating intervertebral disc degeneration. This study highlights a promising approach for avascular dense connective tissue treatment through intelligent NO release, effectively overcoming "AF biological barriers" and programmable treatment.

Utilizing stem cell-secreted molecules as a versatile toolbox for skin regenerative medicine

Stem cells are recognized as an important target and tool in regenerative engineering. In this study, we explored the feasibility of engineering amniotic fluid-derived mesenchymal stem cell-secreted molecules (afMSC-SMs) as a versatile bioactive material for skin regenerative medicine applications in a time- and cost-efficient and straightforward manner. afMSC-SMs, obtained in powder form through ethanol precipitation, effectively contributed to preserving the self-renewal capacity and differentiation potential of primary human keratinocytes (pKCs) in a xeno-free environment, offering a potential alternative to traditional culture methods for their long-term in vitro expansion, and allowed them to reconstitute a fully stratified epithelium sheet on human dermal fibroblasts. Furthermore, we demonstrated the flexibility of afMSC-SMs in wound healing and hair regrowth through injectable hydrogel and nanogel-mediated transdermal delivery systems, respectively, expanding the pool of regenerative applications. This cell-free approach may offer several potential advantages, including streamlined manufacturing processes, scalability, controlled formulation, longer shelf lives, and mitigation of risks associated with living cell transplantation. Accordingly, afMSC-SMs could serve as a promising therapeutic toolbox for advancing cell-free regenerative medicine, simplifying their broad applicability in various clinical settings.

Transforming Medicinal Oil into Advanced Gel: An Update on Advancements

The present study delves into the evolution of traditional Ayurvedic oil preparations through innovative strategies to develop advanced gel formulations, aiming at amplifying their therapeutic efficacy. Ayurvedic oils have a rich historical context in healing practices, yet their conversion into contemporary gel-based formulations represents a revolutionary approach to augment their medicinal potential. The primary objective of this transformation is to leverage scientific advancements and modern pharmaceutical techniques to enhance the application, absorption, and overall therapeutic impact of these traditional remedies. By encapsulating the essential constituents of Ayurvedic oils within gel matrices, these novel strategies endeavor to improve their stability, bioavailability, and targeted delivery mechanisms. This review highlights the fusion of traditional Ayurvedic wisdom with cutting-edge pharmaceutical technology, paving the way for more effective and accessible utilization of these revered remedies in modern healthcare.

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.

The Emerging Role of Silk Fibroin for the Development of Novel Drug Delivery Systems

In order to reduce the toxicological impact on healthy cells and to improve the therapeutic response, many drug delivery systems have been fabricated and analysed, involving the use of different natural and synthetic materials at macro-, micro- and nanoscales. Among the natural materials which have demonstrated a huge potential for the development of effective drug delivery systems, silk fibroin has emerged for its excellent biological properties and for the possibility to be processed in a wide range of forms, which can be compliant with multiple active molecules and pharmaceutical ingredients for the treatment of various diseases. This review aims at presenting silk fibroin as an interesting biopolymer for applications in drug delivery systems, exploring the results obtained in recent works in terms of technological progress and effectiveness in vitro and in vivo.

A nanocomposite competent to overcome solubility and permeation issues of capsaicin and thiocolchicoside simultaneously in gout management: Fabrication of nanocubosomes

This study aimed to formulate nano-cubosomes (NCs) co-loaded with capsaicin (CAP) and thiocolchicoside (TCS) to enhance their bioavailability and minimize associated potential side effects through transdermal delivery alongside their synergistic activity. Twenty seven (27) nano-cubosomal dispersions were prepared according to Box-Behnken factorial design and the effect of CAP, TCS, glyceryl mono oleate (GMO) and poloxamer 407 (P407) concentrations on particle size, polydispersity index (PDI), zeta potential, and entrapment efficiency were assessed. The results revealed that the optimized formulation exhibited a mean droplet size of 503 ± 10.3 nm, PDI of 0.405 ± 0.02, zeta potential of -10.0 ± 1.70 mV and entrapment efficiency of 86.9 ± 3.56 %. The in vivo anti-inflammatory effect of optimized formulation was studied in rats by injecting carrageenan to induce edema. The results of in vivo study showed that transdermal application of nano-cubosomes co-loaded with CAP and TCS significantly (p value < 0.05) improved carrageenan induced inflammation compared with standard treatment. The analgesic activity of optimized formulation was evaluated in rats by using Eddy's hot plate method. The findings of analgesic activity illustrated that the analgesic effects exhibited by test formulation may be associated with increased licking period and inhibition of prostaglandins level. In conclusion, the transdermal application of NCs co-loaded with CAP and TCS may be a promising delivery system for enhancing their bioavailability as well as synergistic analgesic and anti-inflammatory activity in gout management.

Functional biomacromolecules-based microneedle patch for the treatment of diabetic wound

Diabetic wounds are a common complication of diabetes. The prolonged exposure to high glucose and oxidative stress in the wound environment increases the risk of bacterial infection and abnormal angiogenesis, leading to amputation. Microneedle patches have shown promise in promoting the healing of diabetic wounds through transdermal drug delivery. These patches target the four main aspects of diabetic wound treatment: hypoglycemia, antibacterial action, inflammatory regulation, and tissue regeneration. By overcoming the limitations of traditional administration methods, microneedle patches enable targeted therapy for deteriorated tissues. The design of these patches extends beyond the selection of needle tip material and biomacromolecule encapsulated drugs; it can also incorporate near-infrared rays to facilitate cascade reactions and treat diabetic wounds. In this review, we comprehensively summarize the advantages of microneedle patches compared to traditional treatment methods. We focus on the design and mechanism of these patches based on existing experimental articles in the field and discuss the potential for future research on microneedle patches.

Advancements in wound healing: integrating biomolecules, drug delivery carriers, and targeted therapeutics for enhanced tissue repair

Wound healing, a critical biological process vital for tissue restoration, has spurred a global market exceeding $15 billion for wound care products and $12 billion for scar treatment. Chronic wounds lead to delayed or impaired wound healing. Natural bioactive compounds, prized for minimal side effects, stand out as promising candidates for effective wound healing. In response, researchers are turning to nanotechnology, employing the encapsulation of these agents into drug delivery carriers. Drug delivery system will play a crucial role in enabling targeted delivery of therapeutic agents to promote tissue regeneration and address underlying issues such as inflammation, infection, and impaired angiogenesis in chronic wound healing. Drug delivery carriers offer distinct advantages, exhibiting a substantial ratio of surface area to volume and altered physical and chemical properties. These carriers facilitate sustained and controlled release, proving particularly advantageous for the extended process of wound healing, that typically comprise a diverse range of components, integrating both natural and synthetic polymers. Additionally, they often incorporate bioactive molecules. Despite their properties, including poor solubility, rapid degradation, and limited bioavailability, various natural bioactive agents face challenges in clinical applications. With a global research, emphasis on harnessing nanomaterial for wound healing application, this research overview engages advancing drug delivery technologies to augment the effectiveness of tissue regeneration using bioactive molecules. Recent progress in drug delivery has poised to enhance the therapeutic efficacy of natural compounds in wound healing applications.

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

Development of Poly(vinyl alcohol)-Chitosan Composite Nanofibers for Dual Drug Therapy of Wounds

Current trends in localized drug delivery are emphasizing the development of dual drug-loaded electrospun nanofibers (NFs) for an improved therapeutic effect on wounds, especially infected skin wounds. The objective of this study was to formulate a new healing therapy for an infected skin wound. To achieve this goal, this study involved the development and characterization of poly(vinyl alcohol) (PVA)/chitosan nanofibers loaded with ciprofloxacin and rutin hydrate. Polymers and drugs were used in different ratios. Nanofiber morphology was studied by scanning electron microscopy, thermal stability by thermogravimetric analysis, structural determination by the X-ray diffraction method, and integrity by Fourier transform infrared spectroscopy. Dissolution studies were performed to check the drug release behavior of the formulations. Antibacterial studies were performed against Staphylococcus aureus and Pseudomonas aeruginosa. The wound healing efficiency of dual drug-loaded nanofibers was measured by a full-thickness excisional wound model of rabbits. The fabricated nanofibers were smooth in morphology. According to FTIR findings, the drugs remained intact in the nanofibers. The results of swelling ratio and porosity revealed that the pore size was increased as the amount of chitosan was increased up to 30% but a further increase in chitosan concentration reduced the swelling ratio and porosity. Drug release studies of nanofibers depicted an initial burst effect and afterward controlled drug release behavior. Drug-loaded nanofibers showed better activity against S. aureus than P. aeruginosa. The antibacterial efficacy of rutin hydrate with ciprofloxacin was improved compared to that of the formulation having rutin hydrate only, likely due to the additive effect in activity. Based on wound healing studies, nanofibrous membranes acted as a promising wound dressing material as compared to the commercial wound healing formulation. Drug-loaded polymeric nanofibers were successfully fabricated by using an electrospinning method. These nanofibers showed an efficient ability to deliver drugs and treat infected wounds.

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

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

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.

Umbilical therapy for promoting transdermal delivery of topical formulations: Enhanced effect and underlying mechanism

Umbilical paste therapy is a promising method to promote transdermal drug delivery of topical formulations. This work investigated the effect and mechanism of transdermal drug delivery through the umbilical skin. The transdermal permeation studies showed the phenomenon of higher cumulative penetration and faster penetration rates for drug through the umbilical skin compared with non-umbilical skin, namely umbilical pro-permeability. This special transdermal permeability of drugs is influenced by their molecular weight, logP value, ability to form hydrogen bonds, and molecular volume. The underlying mechanism of umbilical pro-permeability was elucidated from unique structure and regulation the effect of drugs on microcirculation in the umbilical skin. Mechanistic studies revealed that this phenomenon was not only associated with the structural and physiological properties of the skin but also to the interactions between drugs and different skin layers. The umbilical pro-permeation is attributed to the thinner stratum corneum layer, differences in stratum corneum lipid composition and keratin structure, and lower levels of intercellular tight junction proteins in the viable epidermis and dermis layer of the skin. Our research indicated that umbilical paste therapy enhanced the transdermal delivery and absorption of drugs by stimulating local blood flow through mast cell activation. Surprisingly, skin temperature modulation and calcitonin gene-related peptide and substance P levels did not appear to significantly affect this process. In conclusion, umbilical drug administration, as a straightforward and non-invasive approach to enhance transdermal drug delivery, presents novel concepts for continued investigation and practical implementation of transdermal drug delivery systems.

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.

Recent advances in drug delivery systems based on natural and synthetic polymes for treating obesity

Obesity stands as a pervasive global public health issue, posing a formidable threat to human well-being as its prevalence continues to surge year by year. Presently, pharmacological treatment remains the favored adjunct strategy for addressing obesity. However, conventional delivery methods suffer from low bioavailability and the potential for side effects, underscoring the pressing need for more efficient and targeted delivery approaches. Recent research has delved extensively into emerging drug delivery systems employing polymers as carriers, with numerous preclinical studies contributing to the growing body of knowledge. This review concentrates on the utilization of natural polymers as drug delivery systems for the treatment of obesity, encompassing recent advancements in both natural and synthetic polymers. The comprehensive exploration includes an analysis of the advantages and disadvantages associated with these polymer carriers. The examination of these characteristics provides valuable insights into potential future developments in the field of drug delivery for obesity treatment.

Capped flexosomes for prominent anti-inflammatory activity: development, optimization, and ex vivo and in vivo assessments

This study aimed to formulate diacerein (DCN)-loaded flexosomes for enhanced efficacy against osteoarthritis. A 23 D-optimal design was employed, investigating the impact of surfactant type (A), surfactant concentration (%w/v) (B), and oleylamine amount (mg) (C). Flexosomes were formulated using a rotary evaporator, and Design-Expert® software was utilized to statistically analyze entrapment efficiency (EE%), zeta potential (ZP), poly-dispersity index (PDI), and particle size (PS) to determine the optimum formula. The selection criteria prioritized increased ZP (as absolute value) and EE%, coupled with decreased PDI and PS. Rigorous physicochemical, in vivo, and ex vivo tests were conducted to validate the safety, stability, and activity of the optimal formula. Physicochemical assessments encompassed pH measurement, transmission electron microscopy, differential scanning calorimetry, release profiles, storage effects, and Fourier transform infrared spectroscopy. In vivo tests included permeation studies, histopathology, anti-inflammatory activity, and skin irritancy, while ex vivo tests focused on permeation parameters and skin deposition. The optimum formula demonstrated high desirability (0.931), along with favorable EE% (90.93%), ZP (- 40.4 mV), particle size (188.55 nm), and sustained behavior. Notably, improved in vivo permeation (132 µm), skin deposition (193.43 µg/cm2), and antinociceptive activity (66%) compared to DCN suspension (48 µm, 66.31 µg/cm2, and 26%, respectively) were observed. The optimal formula also exhibited excellent safety and storage characteristics. In conclusion, DCN-loaded flexosomes exhibit significant potential for effectively managing osteoarthritis.

Integration of polysaccharide electrospun nanofibers with microneedle arrays promotes wound regeneration: A review

Utilizing electrospun nanofibers and microneedle arrays in wound regeneration has been practiced for several years. Researchers have recently asserted that using multiple methods concurrently might enhance efficiency, despite the inherent strengths and weaknesses of each individual approach. The combination of microneedle arrays with electrospun nanofibers has the potential to create a drug delivery system and wound healing method that offer improved efficiency and accuracy in targeting. The use of microneedles with nanofibers allows for precise administration of pharmaceuticals due to the microneedles' capacity to pierce the skin and the nanofibers' role as a drug reservoir, resulting in a progressive release of drugs over a certain period of time. Electrospun nanofibers have the ability to imitate the extracellular matrix and provide a framework for cellular growth and tissue rejuvenation, while microneedle arrays show potential for enhancing tissue regeneration and enhancing the efficacy of wound healing. The integration of electrospun nanofibers with microneedle arrays may be customized to effectively tackle particular obstacles in the fields of wound healing and drug delivery. However, some issues must be addressed before this paradigm may be fully integrated into clinical settings, including but not limited to ensuring the safety and sterilization of these products for transdermal use, optimizing manufacturing methods and characterization of developed products, larger-scale production, optimizing storage conditions, and evaluating the inclusion of multiple therapeutic and antimicrobial agents to increase the synergistic effects in the wound healing process. This research examines the combination of microneedle arrays with electrospun nanofibers to enhance the delivery of drugs and promote wound healing. It explores various kinds of microneedle arrays, the materials and processes used, and current developments in their integration with electrospun nanofibers.

Vitamin B12-loaded chitosan-based nanoparticle-embedded polymeric nanofibers for sublingual and transdermal applications: Two alternative application routes for vitamin B12

Alzheimer's disease (AD) is a neurodegeneration type that is biologically recognizable via β-amyloid plaques and tau neurofibril tangles. Global estimation for the total count of individuals enduring AD will rise up to 131 million by 2050. Investigations suggested the existence of a direct proportion between the likelihood of AD occurrence and vitamin B12 (VB12) hypovitaminosis. Approved VB12 administrations, intramuscular and oral, each has serious defects broaching the demand for alternative routes. This work developed VB12-loaded chitosan/tripolyphosphate/polyvinyl alcohol (CS/TPP/PVA) nanoparticles (NPs) embedded in polyvinylpyrrolidone (PVP) and polyvinylpyrrolidone/polycaprolactone (PVP/PCL) nanofibrous (NFs) produced by pressurized gyration (PG) for sublingual and transdermal routes, respectively. Biomaterials were investigated morphologically, chemically, and thermally. Moreover, degradation, disintegration, release behavior, and release kinetics were analyzed. The effectiveness and safety of nanomaterials were assessed and proven with the alamarBlue test on the Aβ1-42-induced SH-SY5Y model. The final evaluation suggested the feasibility, safety, and effectiveness of produced systems. Consequently, two alternative VB12 application routes were developed with high effectivity and low toxicity with the power of nanotechnology.

Synthesis of aminolyzed gelatin-mediated chitosan as pH-responsive drug-carrying porous scaffolds

Bio-based drug delivery devices have gained enormous interest in the biomedical field due to their biocompatible attributes. Extensive research is being conducted on chitosan-based devices for drug delivery applications. Chitosan being hydrophobic under neutral conditions makes it difficult to interact with a polar drug of curcumin. We tended to make it polar through sol-gel synthesis and modification via PEGylation, alkaline hydrolysis, and aminolysis. Such alterations could make the chitosan-based scaffolds porous, hydrophilic, amino-functionalized, and pH-responsive. The ninhydrin assay confirmed that a successful aminolysis occurred, and the chemical interaction among the precursors was explained under infrared spectroscopy. The scanning morphology of the optimum aminolyzed membrane appeared to be porous with an average pore size of 320 ± 20 nm. The aminolyzed chitosan membrane was found thermally stable up to 310 °C, hydrophilic with a water contact angle of 23.4°, moderate flowablity, and porous (97 ± 5 %, w/w) against ethanol. The curcumin-loaded chitosan membrane expressed the UV-protection behavior of 99 %. The curcumin-loading and release phenomena were found pH-responsive. The curcumin release results were evaluated through specific kinetic models. This study could be the first report on the amphiphilic, porous, and swellable drug-loaded gelatin/chitosan membrane with pH-responsive loading and release of curcumin for potential drug delivery applications.

Advanced Formulation Approaches for Proteins

Proteins and peptides are highly desirable as therapeutic agents, being highly potent and specific. However, there are myriad challenges with processing them into patient-friendly formulations: they are often unstable and have a tendency to aggregate or degrade upon storage. As a result, the vast majority of protein actives are delivered parenterally as solutions, which has a number of disadvantages in terms of cost, accessibility, and patient experience. Much work has been undertaken to develop new delivery systems for biologics, but to date this has led to relatively few products on the market. In this chapter, we review the challenges faced when developing biologic formulations, discuss the technologies that have been explored to try to overcome these, and consider the different delivery routes that can be applied. We further present an overview of the currently marketed products and assess the likely direction of travel in the next decade.

Non-Invasive Delivery of Insulin for Breaching Hindrances against Diabetes

Insulin is recognized as a crucial weapon in managing diabetes. Subcutaneous (s.c.) injections are the traditional approach for insulin administration, which usually have many limitations. Numerous alternative (non-invasive) slants through different routes have been explored by the researchers for making needle-free delivery of insulin for attaining its augmented absorption as well as bioavailability. The current review delineating numerous pros and cons of several novel approaches of non-invasive insulin delivery by overcoming many of their hurdles. Primary information on the topic was gathered by searching scholarly articles from PubMed added with extraction of data from auxiliary manuscripts. Many approaches (discussed in the article) are meant for the delivery of a safe, effective, stable, and patient friendly administration of insulin via buccal, oral, inhalational, transdermal, intranasal, ocular, vaginal and rectal routes. Few of them have proven their clinical efficacy for maintaining the glycemic levels, whereas others are under the investigational pipe line. The developed products are comprising of many advanced micro/nano composite technologies and few of them might be entering into the market in near future, thereby garnishing the hopes of millions of diabetics who are under the network of s.c. insulin injections.

Biofunctional Inorganic Layered Double Hydroxide Nanohybrid Enhances Immunotherapeutic Effect on Atopic Dermatitis Treatment

Atopic dermatitis (AD) is a widespread, recurrent, and chronic inflammatory skin condition that imposes a major burden on patients. Conventional treatments, such as corticosteroids, are associated with various side effects, underscoring the need for innovative therapeutic approaches. In this study, the possibility of using indole-3-acetic acid-loaded layered double hydroxides (IAA-LDHs) is evaluated as a novel treatment for AD. IAA is an auxin-class plant hormone with antioxidant and anti-inflammatory effects. Following the synthesis of IAA-LDH nanohybrids, their ability to induce M2-like macrophage polarization in macrophages obtained from mouse bone marrow is assessed. The antioxidant activity of IAA-LDH is quantified by assessing the decrease in intracellular reactive oxygen species levels. The anti-inflammatory and anti-atopic characteristics of IAA-LDH are evaluated in a mouse model of AD by examining the cutaneous tissues, immunological organs, and cells. The findings suggest that IAA-LDH has great therapeutic potential as a candidate for AD treatment based on its in vitro and in vivo modulation of AD immunology, enhancement of macrophage polarization, and antioxidant activity. This inorganic drug delivery technology represents a promising new avenue for the development of safe and effective AD treatments.

Glass Microneedles: A Case Study for Regulatory Approval Using a Quality by Design Approach

In this paper, a roadmap is provided for the regulatory approval of one of the exciting and dynamic drug delivery fields, microneedles, by using a Quality by Design approach to pharmaceutical product development. In this regard, a quality target product profile (QTPP) and the critical quality attributes (CQA) of microneedles are identified. A case study of the recently patented method of fabricating glass microneedles entirely from a therapeutic agent, thus eliminating the requirement for additional excipients is discussed. The glass microneedle, ArrayPatch, is a propriety wearable device with platform potential consisting of an array of sharp, but painless, dissolvable microneedles manufactured with 100% drug. The microneedles penetrate the skin on application and dissolve to deliver a locally effective dose. The in vitro characterization of the microneedle CQAs under WHO-guided stability conditions will be described to assess the manufacturing readiness of ArrayPatch.  A live technical video is also provided, presenting a unique procedure of jugular vein cannulation through the ear vein of a pig animal model to study the in vivo pharmacokinetics of ArrayPatch compared to standard-of-care marketed products.

Recent update on alginate based promising transdermal drug delivery systems

Alongside oral delivery of therapeutics, transdermal delivery systems have gained increased patient acceptability over past few decades. With increasing popularity, novel techniques were employed for transdermal drug targeting which involves microneedle patches, transdermal films and hydrogel based formulations. Hydrogel forming ability along with other rheological behaviour makes natural polysaccharides an attractive option for transdermal use. Being a marine originated anionic polysaccharide, alginates are widely used in pharmaceutical, cosmetics and food industries. Alginate possesses excellent biodegradability, biocompatibility and mucoadhesive properties. Owing to many favourable properties required for transdermal drug delivery systems (TDDS), the application of alginates are increasing in recent times. This review summarizes the source and properties of alginate along with several transdermal delivery techniques including the application of alginate for respective transdermal systems.

Innovative Topical Patches for Non-Melanoma Skin Cancer: Current Challenges and Key Formulation Considerations

Non-melanoma skin cancer (NMSC) is the most prevalent malignancy worldwide, with approximately 6.3 million new cases worldwide in 2019. One of the key management strategies for NMSC is a topical treatment usually utilised for localised and early-stage disease owing to its non-invasive nature. However, the efficacy of topical agents is often hindered by poor drug penetration and patient adherence. Therefore, various research groups have employed advanced drug delivery systems, including topical patches to overcome the problem of conventional topical treatments. This review begins with an overview of NMSC as well as the current landscape of topical treatments for NMSC, specifically focusing on the emerging technology of topical patches. A detailed discussion of their potential to overcome the limitations of existing therapies will then follow. Most importantly, to the best of our knowledge, this work unprecedentedly combines and discusses all the current advancements in innovative topical patches for the treatment of NMSC. In addition to this, the authors present our insights into the key considerations and emerging trends in the construction of these advanced topical patches. This review is meant for researchers and clinicians to consider utilising advanced topical patch systems in research and clinical trials toward localised interventions of NMSC.

Evolution of Transdermal Drug Delivery Devices and Novel Microneedle Technologies: A Historical Perspective and Review

The history of transdermal drug delivery is as old as humankind. Transdermal drug delivery has undergone three generations of development; the third generation has involved the use of medical devices and instruments. This review provides a historical perspective on the primary approaches employed in the three generations of transdermal drug delivery. In addition, we explore some of the recently developed transdermal techniques that are deemed promising in the field of drug delivery. We discuss how advances in these techniques have led to the development of devices for the delivery of a therapeutically effective amount of drug across human skin and highlight the limitations of the first- and second-generation drug delivery tools. As such, a review of the performance of these techniques and the toxicity of the devices used in transdermal drug delivery are considered. In the last section of the review, a discussion of the fabrication and operation of different types of microneedles is presented. The applications of microneedles in the sensing and delivery of various therapeutic agents are described in detail. Furthermore, an overview of the efficacy of microneedles as emerging tools for the controlled release of drugs is presented.

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.

Biodegradable Microneedles Array with Dual-Release Behavior and Parameter Optimization by Finite Element Analysis

Microneedles (MNs) are particularly attractive for transdermal administration because of the improved safety, patient compliance and convenience. Dissolving MNs could provide rapid transdermal delivery, but with relatively low mechanical strength and almost no sustainability. On the other hand, hydrogel MNs are complicated to fabricate and have risk concerns. Herein, we developed a biodegradable MNs array composed of biocompatible silk fibroin and poly(vinyl alcohol) to overcome these limitations. Finite element analysis was employed for parameter optimization. The MNs array fabricated by the optimal parameters and material displayed sufficient mechanical strength to disrupt stratum corneum and formed microchannels for transdermal delivery. Dual-release profile was observed in the MNs array, with rapid release in the beginning, and prolonged release afterward. This release behavior fits Weibull release model and is favorable for topical application. The initial immediate release can quickly deliver active compounds to reach the therapeutic effective concentration and facilitate skin penetration, and the sustained release may supply the skin with active compounds over a prolonged period. This biodegradable MNs array is easy to fabricate, mechanically robust, could eliminate safety concerns, and provide the sustainability and advantage for large-scale production.

Advances and Prospects for Hydrogel-Forming Microneedles in Transdermal Drug Delivery

Transdermal drug delivery (TDD) is one of the key approaches for treating diseases, avoiding first-pass effects, reducing systemic adverse drug reactions and improving patient compliance. Microneedling, iontophoresis, electroporation, laser ablation and ultrasound facilitation are often used to improve the efficiency of TDD. Among them, microneedling is a relatively simple and efficient means of drug delivery. Microneedles usually consist of micron-sized needles (50-900 μm in length) in arrays that can successfully penetrate the stratum corneum and deliver drugs in a minimally invasive manner below the stratum corneum without touching the blood vessels and nerves in the dermis, improving patient compliance. Hydrogel-forming microneedles (HFMs) are safe and non-toxic, with no residual matrix material, high drug loading capacity, and controlled drug release, and they are suitable for long-term, multiple drug delivery. This work reviewed the characteristics of the skin structure and TDD, introduced TDD strategies based on HFMs, and summarized the characteristics of HFM TDD systems and the evaluation methods of HFMs as well as the application of HFM drug delivery systems in disease treatment. The HFM drug delivery system has a wide scope for development, but the translation to clinical application still has more challenges.

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (<30 s) after insertion into porcine skin. However, HA-MN showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications.

From Plants to Wound Dressing and Transdermal Delivery of Bioactive Compounds

Transdermal delivery devices and wound dressing materials are constantly improved and upgraded with the aim of enhancing their beneficial effects, biocompatibility, biodegradability, and cost effectiveness. Therefore, researchers in the field have shown an increasing interest in using natural compounds as constituents for such systems. Plants, as an important source of so-called "natural products" with an enormous variety and structural diversity that still exceeds the capacity of present-day sciences to define or even discover them, have been part of medicine since ancient times. However, their benefits are just at the beginning of being fully exploited in modern dermal and transdermal delivery systems. Thus, plant-based primary compounds, with or without biological activity, contained in gums and mucilages, traditionally used as gelling and texturing agents in the food industry, are now being explored as valuable and cost-effective natural components in the biomedical field. Their biodegradability, biocompatibility, and non-toxicity compensate for local availability and compositional variations. Also, secondary metabolites, classified based on their chemical structure, are being intensively investigated for their wide pharmacological and toxicological effects. Their impact on medicine is highlighted in detail through the most recent reported studies. Innovative isolation and purification techniques, new drug delivery devices and systems, and advanced evaluation procedures are presented.

Recent advances in dosage form design for the elderly: a review

INTRODUCTION

With the increase in the elderly population and the prevalence of multiple medical conditions, medication adherence, and efficacy have become crucial for the effective management of their health. The aging population faces unique challenges that need to be addressed through advancements in drug delivery systems and formulation technologies.

AREAS COVERED

The current review highlights the recent advances in dosage form design for older individuals, with consideration of their specific physiological and cognitive changes. Various dosage forms, such as modified-release tablets/capsules, chewable tablets, and transdermal patches, can be tailored to meet the specific needs of elderly patients. Advancements in drug delivery systems, such as nanotherapeutics, additive manufacturing (three-dimensional printing), and drug-food combinations, improve drug delivery and efficacy and overcome challenges, such as dysphagia and medication adherence.

EXPERT OPINION

Regulatory guidelines and considerations are crucial in ensuring the safe utilization of medications among older adults. Important factors to consider include geriatric-specific guidelines, safety considerations, labeling requirements, clinical trial considerations, and adherence and accessibility considerations.

A Soft Skin Adhesive (SSA) Patch for Extended Release of Pirfenidone in Burn Wounds

As much as half or more of deep partial-thickness burn wounds develop hypertrophic scarring and contracture. Once formed, treatments are only minimally effective. Pirfenidone (Pf), indicated for treatment of idiopathic pulmonary fibrosis, is an anti-inflammatory and anti-fibrotic small molecule that potentially can be repurposed as a preventative against scarring in burn wounds. We present a drug-in-matrix patch with a soft skin adhesive (SSA) wound-contacting layer for multi-day drug delivery of Pf into burn wounds at the point of injury. Our patch construction consists of an SSA adhesive layer (Liveo™ MG7-9850, Dupont, Wilmington, DE, USA) for wound fixation, an acrylic co-polymer drug matrix (DURO-TAK 87-2852, Henkel, Düsseldorf, Germany) as the drug (Pf) reservoir, and an outermost protective polyurethane backing. By employing a drug-in-matrix patch design, Pf can be loaded as high as 2 mg/cm². Compared to the acrylic co-polymer adhesive patch preparations and commercial films, adding an SSA layer markedly reduces skin stripping observed under scanning electron microscopy (SEM). Moreover, the addition of varying SSA thicknesses did not interfere with the in vitro release kinetics or drug permeation in ex vivo porcine skin. The Pf patch can be easily applied onto and removed from deep partial-thickness burn wounds on Duroc pigs. Continuous multi-day dosing of Pf by the patches (>200 μg/cm²/day) reduced proinflammatory biomarkers in porcine burn wounds. Pf patches produced by the manual laboratory-scale process showed excellent stability, maintaining intact physical patch properties and in vitro biological activity for up to one year under long-term (25 °C at 60% RH) and 6 months under accelerated (40 °C at 75% RH) test conditions. To manufacture our wound safe-and-extended-release patch, we present scale-up processes using a machine-driven automated roll-to-roll pilot scale coater.

Wound Gel with Antimicrobial Effects Based on Polyvinyl Alcohol and Functional Aryloxycyclotriphosphazene

A silver-containing gel based on polyvinyl alcohol and aryloxycyclotriphosphazene containing β-carboxyethenylphenoxy and p-formylphenoxy groups has been developed. Phosphazene was synthesized via the Doebner reaction from hexakis[(4-formyl)phenoxy]cyclotriphosphazene and malonic acid and characterized by ¹H, ¹³C, and ³¹P NMR spectroscopy and MALDI-TOF mass spectrometry. The study of the gel using scanning electron microscopy showed that the gel contains open pores and can absorb wound exudate. The maximum water absorption capacity of the gel was 272%, which was reached after 80 min of testing. The antimicrobial activity of the obtained silver-containing gel was evaluated using the diffusion method. The gel was found to inhibit the growth of the main microorganisms in contact with the skin: the bacteria S. aureus, P. aeruginosa, E. coli, B. subtilis, S. epidermidis, and C. stationis and the fungus C. albicans. The study of the wound-healing effect of the gel in vivo showed a decrease in the wound area of the rabbit hind limb by 91.43% (p < 0.05) on the 10th day of observation and a decrease in the content of C-reactive protein in the rabbit blood serum by 1.3 times (p < 0.05).

Preparation and In Vitro Characterization of Microneedles Containing Inclusion Complexes Loaded with Progesterone

OBJECTIVE

In order to improve patient compliance and the ease of use during progesterone application, and to increase the clinical application of progesterone, progesterone was made into a microneedle.

METHODS

Progesterone complexes were prepared using a single-factor and central composite design. In the preparation of the microneedles, the tip loading rate was used as an evaluation index. The selection of tip materials among the biocompatible materials of gelatin (GEL), hyaluronic acid (HA), and polyvinylpyrrolidone (PVP), and the use of polyvinyl alcohol (PVA) and hydroxypropyl cellulose (HPC) as backing layers, respectively, were carried out and the resulting microneedles were evaluated accordingly.

RESULTS

The progesterone inclusion complexes prepared at a molar ratio of 1:2.16 progesterone and hydroxypropyl-β-cyclodextrin (HP-β-CD), a temperature of 50 °C, and reaction time of 4 h had high encapsulation and drug-loading capacities of 93.49% and 9.55%, respectively. Gelatine was finally chosen as the material for the preparation of the micro-needle tip based on the drug loading rate of the tip. Two types of microneedles were prepared: one with 7.5% GEL as the tip and 50% PVA as the backing layer, and one with 15% GEL as the tip and 5% HPC as the backing layer. The microneedles of both prescriptions exhibited good mechanical strength and penetrated the skin of rats. The needle tip loading rates were 49.13% for the 7.5% GEL-50% PVA microneedles and 29.31% for the 15% GEL-5% HPC microneedles. In addition, in vitro release and transdermal experiments were performed using both types of microneedles.

CONCLUSION

The microneedles prepared in this study enhanced the in vitro transdermal amount of progesterone drug by releasing the drug from the microneedle tip into the subepidermis.

Electro-Responsive Conductive Blended Hydrogel Patch

The proposed electro-responsive hydrogel has great benefit for transdermal drug delivery system (TDDS) applications. To improve the physical or chemical properties of hydrogels, a number of researchers have previously studied the mixing efficiencies of the blended hydrogels. However, few studies have focused on improving the electrical conductivity and drug delivery of the hydrogels. We developed a conductive blended hydrogel by mixing alginate with gelatin methacrylate (GelMA) and silver nanowire (AgNW). We demonstrated that and the tensile strength of blended hydrogels were increased by a factor of 1.8 by blending GelMA and the electrical conductivity was enhanced by a factor of 18 by the addition of AgNW. Furthermore, the GelMA-alginate-AgNW (Gel-Alg-AgNW) blended hydrogel patch enabled on-off controllable drug release, indicating 57% doxorubicin release in response to electrical stimulation (ES) application. Therefore, this electro-responsive blended hydrogel patch could be useful for smart drug delivery applications.

Nafcillin-Loaded Photocrosslinkable Nanocomposite Hydrogels for Biomedical Applications

Skin infections are frequently treated via intravenous or oral administration of antibiotics, which can lead to serious adverse effects and may sometimes contribute to the proliferation of resistant bacterial strains. Skin represents a convenient pathway for delivering therapeutic compounds, ensured by the high number of blood vessels and amount of lymphatic fluids in the cutaneous tissues, which are systematically connected to the rest of the body. This study provides a novel, straightforward method to obtain nafcillin-loaded photocrosslinkable nanocomposite hydrogels and demonstrates their performance as drug carriers and antimicrobial efficacy against Gram-positive bacteria. The novel formulations obtained, based on polyvinylpyrrolidone, tri(ethylene glycol) divinyl ether crosslinker, hydrophilic bentonite nanoclay, and/or two types of photoactive (TiO₂ and ZnO) nanofillers, were characterized using various analytical methods (transmission electron microscopy (TEM), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX), mechanical tests (tension, compression, and shear), ultraviolet-visible spectroscopy (UV-Vis), swelling investigations, and via specific microbiological assays ("agar disc diffusion method" and "time-kill test"). The results reveal that the nanocomposite hydrogel possessed high mechanical resistance, good swelling abilities, and good antimicrobial activity, demonstrating a decrease in the bacteria growth between 3log₁₀ and 2log₁₀ after one hour of direct contact with S. aureus.

Anti-Aging and Depigmentation Effect of a Hyaluronic Acid Mechanically Stabilized Complex on Human Skin Explants

Solar radiation and environmental pollutants are factors that cause changes in the skin that trigger skin aging. The objective of the study is to evaluate the rejuvenating effects of a complex formed by hyaluronic acid supplemented with vitamins, amino acids and oligopeptides in explants of human skin. For this, surplus skin samples have been obtained from donors that have been resected and cultivated on slides with membrane inserts. The complex was administered to some skin explants and the percentage of cells with low, medium and high levels of melanin was evaluated as an indicator of the degree of pigmentation. Other skin segments were irradiated with UVA/UVB, then the product was administered on several slides and the levels of collagen, elastin, sulfated GAG and MMP1 were evaluated. The results show that the administration of the complex significantly reduces the percentage of skin cells with a high melanin content by 16%, and that in skin irradiated with UVA/UVB, there is a decrease in the content of collagen, elastin and sulfate GAGs, and the complex reverses this reduction without changing MMP1 levels. This suggests that the compound has anti-aging and depigmentation effects on the skin, giving a skin rejuvenation appearance.

Ellagic Acid Inclusion Complex-Loaded Hydrogels as an Efficient Controlled Release System: Design, Fabrication and In Vitro Evaluation

Oxidants play a crucial role in the development of oxidative stress, which is linked to disease progression. Ellagic acid is an effective antioxidant with applications in the treatment and prevention of several diseases, since it neutralizes free radicals and reduces oxidative stress. However, it has limited application due to its poor solubility and oral bioavailability. Since ellagic acid is hydrophobic, it is difficult to load it directly into hydrogels for controlled release applications. Therefore, the purpose of this study was to first prepare inclusion complexes of ellagic acid (EA) with hydroxypropyl-β-cyclodextrin and then load them into carbopol-934-grafted-2-acrylamido-2-methyl-1-propane sulfonic acid (CP-g-AMPS) hydrogels for orally controlled drug delivery. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to validate ellagic acid inclusion complexes and hydrogels. There was slightly higher swelling and drug release at pH 1.2 (42.20% and 92.13%) than at pH 7.4 (31.61% and 77.28%), respectively. Hydrogels had high porosity (88.90%) and biodegradation (9.2% per week in phosphate-buffered saline). Hydrogels were tested for their antioxidant properties in vitro against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Additionally, the antibacterial activity of hydrogels was demonstrated against Gram-positive bacterial strains (Staphylococcus aureus and Escherichia coli) and Gram-negative bacterial strains (Pseudomonas aeruginosa).

Transdermal on-demand drug delivery based on an iontophoretic hollow microneedle array system

Transdermal drug delivery has emerged as an alternative administration route for therapeutic drugs, overcoming current issues in oral and parenteral administration. However, this technology is hindered by the low permeability of the stratum corneum of the skin. In this work, we develop a synergic combination of two enhancing technologies to contribute to an improved and on-demand drug delivery through an iontophoretic system coupled with hollow microneedles (HMNs). For the first time, a polymeric HMN array coupled with integrated iontophoresis for the delivery of charged molecules and macromolecules (e.g. proteins) is devised. To prove the concept, methylene blue, fluorescein sodium, lidocaine hydrochloride, and bovine serum albumin-fluorescein isothiocyanate conjugate (BSA-FITC) were first tested in an in vitro setup using 1.5% agarose gel model. Subsequently, the ex vivo drug permeation study using a Franz diffusion cell was conducted, exhibiting a 61-fold, 43-fold, 54-fold, and 17-fold increment of the permeation of methylene blue, fluorescein sodium, lidocaine hydrochloride, and BSA-FITC, respectively, during the application of 1 mA cm^-2 current for 6 h. Moreover, the total amount of drug delivered (i.e. in the skin and receptor compartment) was analysed to untangle the different delivery profiles according to the types of molecule. Finally, the integration of the anode and cathode into an iontophoretic hollow microneedle array system (IHMAS) offers the full miniaturisation of the concept. Overall, the IHMAS device provides a versatile wearable technology for transdermal on-demand drug delivery that can improve the administration of personalised doses, and potentially enhance precision medicine.

Mechanistic insights into the effect of drug content on adhesive properties of transdermal patch containing lidocaine

This study aims to shed light on the relationship between drug content and adhesive properties in drug-in-adhesive transdermal patch, and to elucidate molecular mechanisms from the perspective of polymer chain mobility. Lidocaine was selected as model drug. Two acrylate pressure sensitive adhesives (PSAs) with different polymer chain mobility were synthesized. Tack adhesion, shear adhesion and peel adhesion of PSAs with 0, 5%, 10%, 15% and 20% w/w lidocaine contents were tested. Polymer chain mobility was determined by rheology and modulated differential scanning calorimetry experiments. Drug-PSA interaction was analyzed by FT-IR. The effect of drug content on free volume of PSA were determined by positron annihilation lifetime spectroscopy and molecular dynamics simulation. It was found that the polymer chain mobility of PSA was increased with increasing drug content. Due to the variation of polymer chain mobility, tack adhesion increased, and shear adhesion decreased. It was proved that interactions between polymer chains were destroyed by drug-PSA interactions, free volume between polymer chains was expanded, resulting in the increase of polymer chain mobility. We can conclude that the effect of drug content on polymer chain mobility should be considered, when designing a transdermal drug delivery system with controlled and satisfactory adhesion.

Tolerability, acceptability, and reproducibility of topical STAR particles in human subjects

Topical delivery to treat dermatological disease is constrained by low skin permeability to most drugs due to the stratum corneum barrier. STAR particles containing microneedle protrusions can be topically applied on the skin to create micropores that dramatically increase skin permeability, even to water-soluble compounds and macromolecules. This study addresses the tolerability, acceptability, and reproducibility of STAR particles rubbed on the skin at multiple pressures and after multiple applications to human subjects. One-time STAR particle application at pressures between 40 and 80 kPa showed that skin microporation and erythema directly correlated with increased pressure, and 83% of subjects reported STAR particles to be comfortable at all pressures. Repeated application of STAR particles for 10 consecutive days at 80 kPa showed that skin microporation (~0.5% of skin area), erythema (low-to-moderate), and comfort with self-administration (75%) were similar over the course of the study. Comfort of sensations associated with STAR particles increased from 58% to 71% during the study, and familiarity with STAR particles increased from 12.5% to 50% of subjects reporting STAR particle application not feeling different from other skin products. This study demonstrates that topically applied STAR particles were well tolerated and highly acceptable after application at various pressures and repeated daily use. These findings further suggest that STAR particles offer a safe and reliable platform to enhance cutaneous drug delivery.

Biphasic drug release from electrospun structures

INTRODUCTION

Biphasic release, as a special drug-modified release profile that combines immediate and sustained release, allows fast therapeutic action and retains blood drug concentration for long periods. Electrospun nanofibers, particularly those with complex nanostructures produced by multi-fluid electrospinning processes, are potential novel biphasic drug delivery systems (DDSs).

AREAS COVERED

This review summarizes the most recent developments in electrospinning and related structures. In this review, the role of electrospun nanostructures in biphasic drug release was comprehensively explored. These electrospun nanostructures include monolithic nanofibers obtained through single-fluid blending electrospinning, core-shell and Janus nanostructures prepared via bifluid electrospinning, three-compartment nanostructures obtained via trifluid electrospinning, nanofibrous assemblies obtained through the layer-by-layer deposition of nanofibers, and the combined structure of electrospun nanofiber mats with casting films. The strategies and mechanisms through which complex structures facilitate biphasic release were analyzed.

EXPERT OPINION

Electrospun structures can provide many strategies for the development of biphasic drug release DDSs. However, many issues such as the scale-up productions of complex nanostructures, the in vivo verification of the biphasic release effects, keeping pace with the developments of multi-fluid electrospinning, drawing support from the state-of-the-art pharmaceutical excipients, and the combination with traditional pharmaceutical methods need to be addressed for real applications.

Potential Role of Innate Lymphoid Cells in the Pathogenesis and Treatment of Skin Diseases

Group 2 innate lymphoid cells (ILC2s) are lymphoid cells that are resident in mucosal tissues, especially the skin, which, once stimulated by epithelial cell-derived cytokines, release IL-5, IL-13, and IL-4, as the effectors of type 2 immune responses. This research aims to evaluate the role of ILC2s in the pathogenesis of skin diseases, with a particular focus on inflammatory cutaneous disorders, in order to also elucidate potential therapeutic perspectives. The research has been conducted in articles, excluding reviews and meta-analyses, on both animals and humans. The results showed that ILC2s play a crucial role in the pathogenesis of systemic skin manifestations, prognosis, and severity, while a potential antimelanoma role is emerging from the new research. Future perspectives could include the development of new antibodies targeting or stimulating ILC2 release. This evidence could add a new therapeutic approach to inflammatory cutaneous conditions, including allergic ones.

Cleanroom-Free Fabrication of Microneedles for Multimodal Drug Delivery

Microneedles have recently emerged as a powerful tool for minimally invasive drug delivery and body fluid sampling. To date, high-resolution fabrication of microneedle arrays (MNAs) is mostly achieved by the utilization of sophisticated facilities and expertise. Particularly, hollow microneedles have usually been manufactured in cleanrooms out of silicon, resin, or metallic materials. Such strategies do not support the fabrication of microneedles from biocompatible/biodegradable materials and limit the capability of multimodal drug delivery for the controlled release of different therapeutics through a combination of injection and sustained diffusion. This study implements low-cost 3D printers to fabricate relatively large needle arrays, followed by repeatable shrink-molding of hydrogels to form high-resolution molds for solid and hollow MNAs with controllable sizes. The developed strategy further enables modulating surface topography of MNAs to tailor their surface area and instantaneous wettability for controllable drug delivery and body fluid sampling. Hybrid gelatin methacryloyl (GelMA)/polyethylene glycol diacrylate (PEGDA) MNAs are fabricated using the developed strategy that can easily penetrate the skin and enable multimodal drug delivery. The proposed method holds promise for affordable, controllable, and scalable fabrication of MNAs by researchers and clinicians for controlled spatiotemporal administration of therapeutics and sample collection.