Enhancement in site-specific delivery of carvacrol for potential treatment of infected wounds using infection responsive nanoparticles loaded into dissolving microneedles: A proof of concept study

Carvacrol in asthma management: a comprehensive review of its therapeutic potential and mechanisms of action

Asthma, a chronic inflammatory disorder of the airways, remains a significant global health concern. Current treatments focus on symptom management and inflammation control, but the search for more effective and safer therapies continues. Carvacrol, a naturally occurring monoterpenoid phenol found in essential oils of various plants, has emerged as a promising bioactive compound with potent anti-inflammatory, antioxidant, and bronchodilatory properties. This review explores the potential of carvacrol as a novel therapeutic agent for asthma management. We discuss its mechanisms of action, including modulation of inflammatory pathways, inhibition of oxidative stress, and relaxation of bronchial muscles. Additionally, preclinical and clinical studies evaluating the efficacy and safety of carvacrol in asthma treatment are analyzed. The integration of carvacrol into existing treatment regimens could offer a multifaceted approach to asthma management, enhancing therapeutic outcomes and improving patients' quality of life.

Controlled release of deferiprone using iron-responsive nanoparticles integrated with dissolving microneedle for novel alternative treatments of β-thalassemia major

Iron chelating agents (ICs) such as conventional deferiprone are often ineffective when exposed to normal conditions due to their uncontrolled release when treating iron overload in ß-thalassemia major (ß-TM) due to the effects of blood transfusion. Iron deficiency and gastrointestinal side effects are crucial problems that can occur. Therefore, DFP was prepared as nanoparticles (NPs) coated with an iron-responsive (IR) polymer with an average particle size of 354.70 ± 10 nm to control its release. To facilitate optimal delivery, NP-IR-DFP was integrated into a dissolving microneedle (DMN) fabricated with biodegradable and biocompatible poly(vinylpyrrolidone) and poly(vinyl alcohol) polymers. The results showed that the NP-IR-DMN provided excellent insertion and mechanical strength and dissolved quickly after application. In vitro and ex-vivo studies revealed the more controllable release of NP-IR-DFP after integration with the DMN (NP-IR-DMN) for up to 24 h. Most importantly, the developed formula was hemocompatible and did not irritate the skin or cause tissue damage. Furthermore, the in vivo pharmacokinetics were further investigated for 24 h, which revealed short concentration (Cmax of 0.07 ± 0.03 μg/mL) and t1/2 (3.66 ± 0.76 h) under normal conditions and long-term iron overload-modeling conditions with Cmax (2.90 ± 0.14 μg/mL) and t1/2 (10.13 ± 1.00 h). This approach can extend beyond oral delivery by controlling the release of DFP, which can only be released in conditions of iron overload, and has the potential to prevent iron deficiency and excess, thus increasing the efficacy of DFP in β-TM therapy.

Boosting the antibacterial potency of natural products through nanotechnologies

The advent of bacterial resistance has led to a notable challenge in effectively treating bacterial infections. This highlights the urgent need for the development of novel and effective drugs to combat bacterial infections. Medicinal plants, with their rich and diverse natural compounds, represent a valuable source for the discovery of novel antibacterial agents. Many of these natural compounds exhibit strong antibacterial functions, offering a promising direction for the development of antibacterial drugs. Furthermore, the application of nanotechnology in the development of antibacterial natural products has become a topic of considerable interest due to the advantages it offers, including the potential to enhance drug solubility. The efficacy of natural antibacterial agents is significantly enhanced through nanotechnology. This review offers a comprehensive overview of recent advances in the delivery of natural antibacterial compounds using a range of nanoformulation strategies.

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

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

A macromolecule infliximab loaded reverse nanomicelles-based transdermal hydrogel: An innovative approach against rheumatoid arthritis

Infliximab (IFX) is used as a biotherapeutic agent for the treatment of rheumatoid arthritis (RA); however, its biological activity is lost orally because of variations in gastric pH and enzymatic degradation, and reduced bioavailability. The authors have tried to improve the efficacy of macromolecule delivery through transdermal route. Polycaprolactone-Polyethylene glycol-Polycaprolactone (PCL-PEG-PCL) triblock copolymer previously synthesized and was used as an efficient carrier for the preparation of IFX loaded reverse nanomicelles (IFX-RNMs). The RNMs were fabricated via nanoprecipitation technique, characterized and then were incorporated into a Carbopol-based hydrogel with eucalyptus oil (EO) as a penetration enhancer. The optimized RNMs had a particle size of 72.32 nm and an encapsulation efficiency of 83 %. In vitro release, exhibited a sustained pattern of IFX from the prepared carrier system, ex-vivo skin permeation and fluorescence microscopic studies revealed that IFX-RNMs loaded hydrogel with EO markedly improved permeation. An in vivo study was carried out on a CFA-induced RA mice model that revealed significant improvements in the results of behavioral parameters, biochemical assays, histopathological and radiological analysis. Overall, the results concluded that the IFX-RNMs loaded hydrogel can be used as a suitable approach for treating RA.

Carvacrol/cyclodextrin/ceria nanoparticle/hyaluronate hybrid microneedle for promoted diabetic wound healing through the modulation of microenvironment

Delayed healing due to the persistent microenvironment disorder caused by the hyperglycemia and persistent inflammatory reaction is a core pathological characteristic of diabetic wound. Topical microenvironment modulation represents an important avenue to address delayed healing issue. Microneedles are powerful tools for topical microenvironment modulation as they can effectively deliver therapeutic ingredients into the shallow surface layer of the wound based on their depth-limited tissue penetration capability. Herein, a hybrid microneedle composed of carvacrol (CV), cyclodextrin (CD), mesoporous ceria nanoparticles (MCNs) and hyaluronate (HA) is constructed with objective to modulate the microenvironment within the diabetic wound. The hybrid microneedle is constructed via a two-stage process comprising three stepwise embedding procedures in the first stage and four microneedle casting procedures in the second stage. The physical, chemical and antibacterial performances, as well as the in vitro and in vivo therapeutic potentials, of the hybrid microneedle are evaluated. The therapeutic ingredients, mainly CV and MCNs, incorporated in the microneedle can be readily released into the diabetic wound, and effective microenvironment modulation is realized through the designed antibacterial, antioxidant and anti-inflammatory functions. Consequently, the tissue reconstruction processes including cell proliferation and migration, angiogenesis, and collagen deposition are accelerated due to the improved microenvironment.

Development of three-layer microneedle system for controlled and sustained release of Levonorgestrel: A pioneering approach to long-term contraceptive delivery

The increasing prevalence of unintended pregnancies, a persistent issue affecting public health and hindering progress towards the Sustainable Development Goals (SDGs), highlights the critical need for innovative contraceptive approaches. While current methods, including hormonal contraceptives such as levonorgestrel (LNG), offer potential solutions, challenges like limited access and inconsistent use persist. This study introduces a new approach with the development of a three-layer microneedle (TIMN) containing LNG designed to provide extended contraceptive efficacy. The TIMN was formulated with varying concentrations of polyvinylpyrrolidone (PVP) and polycaprolactone (PCL) in the first layer, resulting in microneedles approximately 700 µm in height. In this study, TIMN demonstrated superior mechanical strength with less than 10% reduction in needle height under compression. The formulations maintained a surface pH within the skin's normal range, ensuring safety and compatibility, while water vapor transmission (WVT) values indicated good stability under high humidity. Moisture absorption ability (MAA) testing showed low water absorption, suggesting suitability for extended use. In vitro release studies revealed that TIMN released 28.34% of LNG after 24 h and up to 97.34% over 14 days, demonstrating controlled and sustained release. Ex vivo studies confirmed TIMN's longer-lasting LNG availability compared to the control, and in vivo pharmacokinetic studies showed that TIMN maintained therapeutic LNG levels for up to 14 days, outperforming oral LNG suspension. Biocompatibility tests, including HET-CAM and hemolysis assays, confirmed TIMN's safety, with no significant irritation or toxicity. Histopathological analysis further supported the absence of adverse reactions. The TIMN formulation, exhibits promising properties for long-term drug delivery, including mechanical strength, stability, controlled release, and biocompatibility, making it a viable candidate for improved contraceptive therapy.

Unveiling the nanoworld of antimicrobial resistance: integrating nature and nanotechnology

A significant global health crisis is predicted to emerge due to antimicrobial resistance by 2050, with an estimated 10 million deaths annually. Increasing antibiotic resistance necessitates continuous therapeutic innovation as conventional antibiotic treatments become increasingly ineffective. The naturally occurring antibacterial, antifungal, and antiviral compounds offer a viable alternative to synthetic antibiotics. This review presents bacterial resistance mechanisms, nanocarriers for drug delivery, and plant-based compounds for nanoformulations, particularly nanoantibiotics (nAbts). Green synthesis of nanoparticles has emerged as a revolutionary approach, as it enhances the effectiveness, specificity, and transport of encapsulated antimicrobials. In addition to minimizing systemic side effects, these nanocarriers can maximize therapeutic impact by delivering the antimicrobials directly to the infection site. Furthermore, combining two or more antibiotics within these nanoparticles often exhibits synergistic effects, enhancing the effectiveness against drug-resistant bacteria. Antimicrobial agents are routinely obtained from secondary metabolites of plants, including essential oils, phenols, polyphenols, alkaloids, and others. Integrating plant-based antibacterial agents and conventional antibiotics, assisted by suitable nanocarriers for codelivery, is a potential solution for addressing bacterial resistance. In addition to increasing their effectiveness and boosting the immune system, this synergistic approach provides a safer and more effective method of tackling future bacterial infections.

Natural products in the treatment of diabetic foot infection

Diabetic foot infections (DFIs) are a significant complication in diabetes mellitus, leading to increased morbidity, hospitalizations, and healthcare burdens. The growing prevalence of antibiotic-resistant pathogens has reduced the efficacy of conventional treatments, highlighting the need for alternative therapeutic strategies. Natural products, known for their antimicrobial, anti-inflammatory, and wound-healing properties, have garnered attention as potential treatments for DFIs. This review examines key natural compounds, including eugenol, thymol, carvacrol, curcumin, and Aloe vera, and their mechanisms of action in combating diabetic infections. We analyze the antimicrobial efficacy of these compounds, their ability to inhibit biofilm formation, and their role in wound healing. The review also explores challenges in integrating natural products into clinical practice and the potential for their use alongside or in place of traditional antibiotic therapies. Our findings suggest that natural products could play a crucial role in developing sustainable and effective treatment strategies for DFIs, especially in the face of rising antimicrobial resistance.

Smart drug delivery and responsive microneedles for wound healing

Wound healing is an ongoing concern for the medical community. The limitations of traditional dressings are being addressed by materials and manufacturing technology. Microneedles (MNs) are a novel type of drug delivery system that has been widely used in cancer therapy, dermatological treatment, and insulin and vaccine delivery. MNs locally penetrate necrotic tissue, eschar, biofilm and epidermis into deep tissues, avoiding the possibility of drug dilution and degradation and greatly improving administration efficiency with less pain. MNs represent a new direction for wound treatment and transdermal delivery. In this study, we summarise the skin wound healing process and the mechanical stimulation of MNs in the context of the wound healing process. We also introduce the structural design and manufacture of MNs. Subsequently, MNs are categorised according to the loaded drugs, where the design of the MNs according to the traumatic biological/biochemical microenvironment (pH, glucose, and bacteria) and the physical microenvironment (temperature, light, and ultrasound) is emphasised. Finally, the advantages of MNs are compared with traditional drug delivery systems and their prospects are discussed.

Carvacrol is potential molecule for diabetes treatment

Diabetes is an important chronic disease that can lead to various negative consequences and complications. In recent years, several new alternative treatments have been developed to improve diabetes. Carvacrol found in essential oils of numerous plant species and has crucial potential effects on diabetes. The anti-diabetic effects of carvacrol have also been comprehensively studied in diabetic animal and cell models. In addition, carvacrol could improve diabetes through affecting diabetes-related enzymes, insulin resistance, insulin sensitivity, glucose uptake, anti-oxidant, and anti-inflammatory mechanisms. The use of carvacrol alone or in combination with anti-diabetic therapies could show a significant potential effect in the treatment of diabetes. This review contributes an overview of the effect of carvacrol in diabetes and anti-diabetic mechanisms.

Microneedles with Implantable Tip-Accumulated Therapeutics for the Long-Term Management of Psoriasis

Methotrexate is successfully used as the gold standard for managing moderate-to-severe psoriasis. However, the low bioavailability and short half-life of the oral pills and the invasiveness of the parenteral injections make these suboptimal therapeutic options. Microneedles, bridging the advantages of the former forms, are successfully used to deliver methotrexate for different therapeutic purposes. However, the utilized dissolving microneedles demand frequent administration, potentially compromising patients' compliance. Additionally, the high toxicity of methotrexate prompts a quest for safer alternatives. Phloretin, a natural compound with confirmed antipsoriatic potential, emerges as a promising candidate. Herein, microneedle patches with separable, slow-degrading tips are developed for the sustained delivery of methotrexate and phloretin, as a comprehensive solution for long-term psoriasis management. Both compounds are individually loaded at varying doses and display sustained-release profiles. The developed microneedle patches demonstrate high mechanical strength, favorable drug delivery efficiency, and remarkable antipsoriatic potential both in vitro in keratinocytes and in vivo in a psoriasis mouse model. Comparative analysis with two subcutaneous injections reveals a similar antipsoriatic efficacy with a single patch of either compound, with prominent phloretin safety. Therefore, the developed patches present a superior alternative to methotrexate's current marketed forms and provide a viable alternative (phloretin) with comparable antipsoriatic efficacy and higher safety.

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

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

Advances of Smart Stimulus-Responsive Microneedles in Cancer Treatment

Microneedles (MNs) have emerged as a highly promising technology for delivering drugs via the skin. They provide several benefits, including high drug bioavailability, non-invasiveness, painlessness, and high safety. Traditional strategies for intravenous delivery of anti-tumor drugs have risks of systemic toxicity and easy development of drug resistance, while MN technology facilitates precise delivery and on-demand release of drugs in local tissues. In addition, by further combining with stimulus-responsive materials, the construction of smart stimulus-responsive MNs can be achieved, which can respond to specific physical/chemical stimuli from the internal or external environment, thereby further improving the accuracy of tumor treatment and reducing toxicity to surrounding tissues/cells. This review systematically summarizes the classification, materials, and reaction mechanisms of stimulus-responsive MNs, outlines the benefits and challenges of various types of MNs, and details their application and latest progress in cancer treatment. Finally, the development prospects of smart MNs in tumor treatment are also discussed, bringing inspiration for future precision treatment of tumors.

Greener healing: sustainable nanotechnology for advanced wound care

Wound healing involves a carefully regulated sequence of events, encompassing pro-inflammatory and anti-inflammatory stages, tissue regeneration, and remodeling. However, in individuals with diabetes, this process gets disrupted due to dysregulation caused by elevated glucose levels and pro-inflammatory cytokines in the bloodstream. Consequently, the pro-inflammatory stage is prolonged, while the anti-inflammatory phase is delayed, leading to impaired tissue regeneration and remodeling with extended healing time. Furthermore, the increased glucose levels in open wounds create an environment conducive to microbial growth and tissue sepsis, which can escalate to the point of limb amputation. Managing diabetic wounds requires meticulous care and monitoring due to the lack of widely available preventative and therapeutic measures. Existing clinical interventions have limitations, such as slow recovery rates, high costs, and inefficient drug delivery methods. Therefore, exploring alternative avenues to develop effective wound-healing treatments is essential. Nature offers a vast array of resources in the form of secondary metabolites, notably polyphenols, known for their antimicrobial, anti-inflammatory, antioxidant, glucose-regulating, and cell growth-promoting properties. Additionally, nanoparticles synthesized through environmentally friendly methods hold promise for wound healing applications in diabetic and non-diabetic conditions. This review provides a comprehensive discussion and summary of the potential wound-healing abilities of specific natural polyphenols and their nanoparticles. It explores the mechanisms of action underlying their efficacy and presents effective formulations for promoting wound-healing activity.

Research into how carvacrol and metformin affect several human proteins in a hyperglycemic condition: A comparative study in silico and in vitro

Carvacrol (CV) is an organic compound found in the essential oils of many aromatic herbs. It is nearly unfeasible to analyze all the current human proteins for a query ligand using in vitro and in vivo methods. This study aimed to clarify whether CV possesses an anti-diabetic feature via Docking-based inverse docking and molecular dynamic (MD) simulation and in vitro characterization against a set of novel human protein targets. Herein, the best poses of CV docking simulations according to binding energy ranged from -7.9 to -3.5 (kcal/mol). After pathway analysis of the protein list through GeneMANIA and WebGestalt, eight interacting proteins (DPP4, FBP1, GCK, HSD11β1, INSR, PYGL, PPARA, and PPARG) with CV were determined, and these proteins exhibited stable structures during the MD process with CV. In vitro application, statistically significant results were achieved only in combined doses with CV or metformin. Considering all these findings, PPARG and INSR, among these target proteins of CV, are FDA-approved targets for treating diabetes. Therefore, CV may be on its way to becoming a promising therapeutic compound for treating Diabetes Mellitus (DM). Our outcomes expose formerly unexplored potential target human proteins, whose association with diabetic disorders might guide new potential treatments for DM.

Design Strategy of Microneedle Systems for Skin Wound Healing: Based on the Structure of Tips and Therapeutic Methodologies

The skin, being the largest organ of the human body, is susceptible to damage resulting in wounds that are vulnerable to pathogenic attacks and fail to provide effective protection for internal tissues. Therefore, it is crucial to expedite wound healing. In recent years, microneedles have garnered significant attention as an innovative drug delivery system owing to their noninvasive and painless administration, simplified application process, precise control over drug release, and versatile loading capabilities. Consequently, they hold immense potential for the treatment of skin wound. This review presents a comprehensive design strategy for the microneedle system in promoting skin wound healing. First, the process of skin wound healing and the characteristics of specific wounds are elucidated. The design strategies for microneedles are subsequently presented and classified based on their structural and therapeutic methodologies. Finally, a succinct recapitulation of the previously discussed points and a prospective analysis are provided.

Fabrication and Evaluation of Hyaluronidase-Responsive Scaffolds by Electrospinning with Antibacterial Properties for Tympanic Membrane Repair

Tympanic membrane perforation (TMP) is prevalent in clinical settings. Patients with TMPs often suffer from infections caused by Staphylococcus aureus and Pseudomonas aeruginosa, leading to middle ear and external ear canal infections, which hinder eardrum healing. The objective of this study is to fabricate an enzyme-responsive antibacterial electrospun scaffold using poly(lactic-co-glycolic acid) and hyaluronic acid for the treatment of infected TMPs. The properties of the scaffold were characterized, including morphology, wettability, mechanical properties, degradation properties, antimicrobial properties, and biocompatibility. The results indicated that the fabricated scaffold had a core-shell structure and exhibited excellent mechanical properties, hydrophobicity, degradability, and cytocompatibility. Furthermore, in vitro bacterial tests and ex vivo investigations on eardrum infections suggested that this scaffold possesses hyaluronidase-responsive antibacterial properties. It may rapidly release antibiotics when exposed to the enzyme released by S. aureus and P. aeruginosa. These findings suggest that the scaffold has great potential for repairing TMPs with infections.

Diagnostic, Therapeutic, and Theranostic Multifunctional Microneedles

Microneedles (MNs) have maintained their popularity in therapeutic and diagnostic medical applications throughout the past decade. MNs are originally designed to gently puncture the stratum corneum layer of the skin and have lately evolved into intelligent devices with functions including bodily fluid extraction, biosensing, and drug administration. MNs offer limited invasiveness, ease of application, and minimal discomfort. Initially manufactured solely from metals, MNs are now available in polymer-based varieties. MNs can be used to create systems that deliver drugs and chemicals uniformly, collect bodily fluids, and are stimulus-sensitive. Although these advancements are favorable in terms of biocompatibility and production costs, they are insufficient for the therapeutic use of MNs. This is the first comprehensive review that discusses individual MN functions toward the evolution and development of smart and multifunctional MNs for a variety of novel and impactful future applications. The study examines fabrication techniques, application purposes, and experimental details of MN constructs that perform multiple functions concurrently, including sensing, drug-molecule release, sampling, and remote communication capabilities. It is highly likely that in the near future, MN-based smart devices will be a useful and important component of standard medical practice for different applications.

Targeting Diverse Wounds and Scars: Recent Innovative Bio-design of Microneedle Patch for Comprehensive Management

Wounds and the subsequent formation of scars constitute a unified and complex phased process. Effective treatment is crucial; however, the diverse therapeutic approaches for different wounds and scars, as well as varying treatment needs at different stages, present significant challenges in selecting appropriate interventions. Microneedle patch (MNP), as a novel minimally invasive transdermal drug delivery system, has the potential for integrated and programmed treatment of various diseases and has shown promising applications in different types of wounds and scars. In this comprehensive review, the latest applications and biotechnological innovations of MNPs in these fields are thoroughly explored, summarizing their powerful abilities to accelerate healing, inhibit scar formation, and manage related symptoms. Moreover, potential applications in various scenarios are discussed. Additionally, the side effects, manufacturing processes, and material selection to explore the clinical translational potential are investigated. This groundwork can provide a theoretical basis and serve as a catalyst for future innovations in the pursuit of favorable therapeutic options for skin tissue regeneration.

Facile synthesis of 2-hydroxy-β-cyclodextrin/polyacrylamide/carbazole hydrogel and its application for the treatment of infected wounds in a murine model

This work aimed to synthesize hydrogels by combining carbazole (Carb) with 2-hydroxy, β-cyclodextrin (HPβCD)/polyacrylamide (PAA) hybrid complexes. The hydrogels were then evaluated for their potential use in treating infected wounds. The physicochemical structures of the preparations were evaluated using several characterization methods including FTIR, FESEM, EDX, XRD, pH sensitivity, and TGA. Moreover, In vitro release, toxicity, antibacterial activity and in vivo infected wound healing activity were evaluated. Physicochemical testing verified the effective synthesis of the preparations and the timely release of Carb. The P(AA-co-AM)/HPβCD material exhibited an open structure characterized by macroscopic voids, whereas the hydrogels displayed surfaces that were not uniform. The FTIR analysis revealed the creation of a novel polymeric hydrogel composed of HPβCD as the main polymer structure. The hydrogels exhibited good reversible swelling and recoverable deformation, with an optimal swelling ratio of 30.12 achieved at pH 7.4. The antibacterial and safety of the formulations were validated by in vitro studies. β.Dex/PAA/Carb hydrogels have been shown to effectively expedite the healing of infected wounds by promoting the production of CD31, FGF-2, and COL1A, while reducing the levels of ROS, CD68, COX-2, and NF-κB. Overall, the combination of Carb, β.Dex, and PAA molecules had a synergistic impact on the healing process of infected wounds.

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

PURPOSE

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

METHODS

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

RESULT

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

CONCLUSION

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

Validation of spectrophotometric and colorimetric methods to quantify clindamycin in skin tissue: application to in vitro release and ex vivo dermatokinetic studies from separable effervescent microarray patch loaded bacterially sensitive microparticle

Diabetes mellitus can cause diabetic foot infection (DFI) complications. DFI is generally caused by infection from bacteria and Methicillin-Resistant Staphylococcus aureus (MRSA) which is resistant to several antibiotics. Application therapy of clindamycin (CLY) administration with the oral route has low bioavailability and non-selective distribution of antibiotics towards bacteria intravenously. In this research, CLY was developed into bacterially sensitive microparticles (MPs) which were further incorporated into a separable effervescent microarray patch (SEMAP) system to increase the selective and responsive to DFI-causing bacteria of CLY. To support this formulation, we explore the potential of silver nanoparticles (AgNPs) towards the UV-Vis spectrophotometry method. The analytical method was validated in phosphate-buffered saline (PBS), tryptic soy broth (TSB), and skin tissue to quantify CLY, CLY loaded in microparticle, and SEMAP system. The developed analytical method was suitable for the acceptance criteria of ICH guidelines. The results showed that the correlation coefficients were linear ≥ 0.999. The values of LLOQ towards PBS, TSB, and skin tissue were 2.02 µg/mL, 4.29 µg/mL, and 2.31 µg/mL, respectively. These approaching methods were also found to be accurate and precise without being affected by dilution integrity. The presence of Staphylococcus aureus bacteria culture can produce lipase enzymes that can lysing the microparticle matrix. Drug release studies showed that bacterial infection in the high drug release microparticle sensitive bacteria and high drug retention in ex vivo dermatokinetic in rat skin tissue media. In addition, in vivo studies were required to quantify the CLY inside in further analytical validation methods.

The Necessity to Investigate In Vivo Fate of Nanoparticle-Loaded Dissolving Microneedles

Transdermal drug delivery systems are rapidly gaining prominence and have found widespread application in the treatment of numerous diseases. However, they encounter the challenge of a low transdermal absorption rate. Microneedles can overcome the stratum corneum barrier to enhance the transdermal absorption rate. Among various types of microneedles, nanoparticle-loaded dissolving microneedles (DMNs) present a unique combination of advantages, leveraging the strengths of DMNs (high payload, good mechanical properties, and easy fabrication) and nanocarriers (satisfactory solubilization capacity and a controlled release profile). Consequently, they hold considerable clinical application potential in the precision medicine era. Despite this promise, no nanoparticle-loaded DMN products have been approved thus far. The lack of understanding regarding their in vivo fate represents a critical bottleneck impeding the clinical translation of relevant products. This review aims to elucidate the current research status of the in vivo fate of nanoparticle-loaded DMNs and elaborate the necessity to investigate the in vivo fate of nanoparticle-loaded DMNs from diverse aspects. Furthermore, it offers insights into potential entry points for research into the in vivo fate of nanoparticle-loaded DMNs, aiming to foster further advancements in this field.

Juniperus oxycedrus L. ssp. Essential Oil Microneedles: A Promising Antimicrobial and Wound Healing Activity

The use of essential oil (EO) in treating infected wounds is still challenging. A lot of effort has been made to make such an application more convenient. Recently, microneedles (MNDs) have been considered as a smart dermal delivery system to overcome the poor absorption and distribution, low bioavailability, and skin penetration of some drugs. The aim of our study is to evaluate the wound healing activity of juniper-EO-loaded MNDs (EO MNDs) against wounds with bacterial and fungal infection. The Polyvinylpyrrolidone (PVP) MNDs were prepared using the gel-filled mold technique and loaded with juniper EO. In vivo models were created and wounds on rats were infected with two clinically isolated bacterial strains Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, Candida albicans was used to mimic fungal infection and juniper EO MNDs were tested. The obtained results showed an improvement in wound healing which started from the third day after application of the juniper EO MNDs, and at the sixth day post-infection, the treated wounds were significantly smaller than untreated wounds. A complete healing was shown by the 12th day after infection. Furthermore, our cytotoxicity results showed a cytotoxic effect of juniper EO MNDs on epithelial cells, which explained the faster wound healing in rats. Our study showed that juniper EO MNDs represent a novel strategy in EO delivery with minimal invasion. Juniper EO MNDs demonstrated significant antimicrobial activity against both the bacterial strains Pseudomonas aeruginosa and Staphylococcus aureus and against one fungal strain, Candida albicans. Finally, application of juniper EO MNDs exerted promising activity in the treatment and healing of wound infection.

Metallic elements combine with herbal compounds upload in microneedles to promote wound healing: a review

Wound healing is a dynamic and complex restorative process, and traditional dressings reduce their therapeutic effectiveness due to the accumulation of drugs in the cuticle. As a novel drug delivery system, microneedles (MNs) can overcome the defect and deliver drugs to the deeper layers of the skin. As the core of the microneedle system, loaded drugs exert a significant influence on the therapeutic efficacy of MNs. Metallic elements and herbal compounds have been widely used in wound treatment for their ability to accelerate the healing process. Metallic elements primarily serve as antimicrobial agents and facilitate the enhancement of cell proliferation. Whereas various herbal compounds act on different targets in the inflammatory, proliferative, and remodeling phases of wound healing. The interaction between the two drugs forms nanoparticles (NPs) and metal-organic frameworks (MOFs), reducing the toxicity of the metallic elements and increasing the therapeutic effect. This article summarizes recent trends in the development of MNs made of metallic elements and herbal compounds for wound healing, describes their advantages in wound treatment, and provides a reference for the development of future MNs.

Carvacrol-Loaded Phytosomes for Enhanced Wound Healing: Molecular Docking, Formulation, DoE-Aided Optimization, and in vitro/in vivo Evaluation

Background

Despite recent advances in wound healing products, phytochemicals have been considered promising and attractive alternatives. Carvacrol (CAR), a natural phenolic compound, has been reported to be effective in wound healing.

Purpose

This work endeavored to develop novel CAR-loaded phytosomes for the enhancement of the wound healing process.

Methods

Molecular docking was performed to compare the affinities of the different types of phospholipids to CAR. Phytosomes were prepared by three methods (thin-film hydration, cosolvency, and salting out) using Lipoid S100 and Phospholipon 90H with three levels of saturation percent (0%, 50%, and 100%), and three levels of phospholipid molar percent (66.67%, 75%, and 80%). The optimization was performed using Design Expert where particle size, polydispersity index, and zeta potential were chosen as dependent variables. The optimized formula (F1) was further investigated regarding entrapment efficiency, TEM, 1H-NMR, FT-IR, DSC, X-RD, in vitro release, ex vivo permeation, and stability. Furthermore, it was incorporated into a hydrogel formulation, and an in vivo study was conducted to investigate the wound-healing properties of F1.

Results

F1 was chosen as the optimized formula prepared via the thin-film hydration method with a saturation percent and a phospholipid molar percent of zero and 66.67, respectively. TEM revealed the spherical shape of phytosomal vesicles with uniform size, while the results of 1H-NMR, FT-IR, DSC, and X-RD confirmed the formation of the phytosomal complex. F1 demonstrated a higher in vitro release and a slower permeation than free CAR. The wound area of F1-treated animals showed a marked reduction associated with a high degree of collagen fiber deposition and enhanced cellular proliferation.

Conclusion

F1 can be considered as a promising remedy for the enhancement of wound healing and hence it would be hoped to undergo further investigation.

Long-acting microneedle formulations

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

Advances in Intelligent Stimuli-Responsive Microneedle for Biomedical Applications

Microneedles (MNs) are a new type of drug delivery method that can be regarded as an alternative to traditional transdermal drug delivery systems. Recently, MNs have attracted widespread attention for their advantages of effectiveness, safety, and painlessness. However, the functionality of traditional MNs is too monotonous and limits their application. To improve the efficiency of disease treatment and diagnosis by combining the advantages of MNs, the concept of intelligent stimulus-responsive MNs is proposed. Intelligent stimuli-responsive MNs can exhibit unique biomedical functions according to the internal and external environment changes. This review discusses the classification and principles of intelligent stimuli-responsive MNs, such as magnet, temperature, light, electricity, reactive oxygen species, pH, glucose, and protein. This review also highlights examples of intelligent stimuli-responsive MNs for biomedical applications, such as on-demand drug delivery, tissue repair, bioimaging, detection and monitoring, and photothermal therapy. These intelligent stimuli-responsive MNs offer the advantages of high biocompatibility, targeted therapy, selective detection, and precision treatment. Finally, the prospects and challenges for the application of intelligent stimuli-responsive MNs are discussed.

Antibacterial study of carbopol-mastic gum/silver nanoparticle-based topical gels with carvacrol/neem bark extract in vitro

BACKGROUND

Resistance to antimicrobial drugs as a result of prolonged use usually results in clinical failure, especially in wound infections. Development of effective antimicrobial therapeutics for the management of infected wounds from a natural source with improved therapeutic effects is a pressing need.

OBJECTIVE

In this study, carbopol-mastic gum-based topical gels were loaded with silver nanoparticles in combination with either neem bark extract or carvacrol oil. The effect of combining silver nanoparticles with neem bark extract or the essential oil carvacrol in the prepared gel formulations was investigated on selected bacterial strains.

METHOD

The prepared gels were characterised by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectroscopy, followed by antimicrobial analysis against selected strains of bacteria.

RESULTS

There was no interaction between the loaded natural extract or essential oil and the polymer used for the preparation of the formulations, which was visible from the FTIR spectra of the formulations. The gels were selective and effective against selected strains of bacteria. However, the combination of the silver nanoparticles with essential oil or natural extract in some of the gel formulations rendered the formulation ineffective against some of the bacterial strains.

CONCLUSION

The gel formulations were effective against bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis which are the common causes of wound infections. Incorporation of silver nanoparticles into the topical formulations with natural extracts is usually a good approach to overcome antibiotic-resistant infections. However, the combination of antibacterial agents must be managed carefully.

Validation of spectrophotometric method to quantify chloramphenicol in fluid and rat skin tissue mimicking infection environment: Application to in vitro release and ex vivo dermatokinetic studies from dissolving microneedle loaded microparticle sensitive bacteria

Cellulitis is a common dermis/subcutaneous tissue skin infection and shared global disease burden, with a higher incidence for males and people aged 45-64 years. Application therapy of chloramphenicol (CHL) has been hindered because of its toxicity and limited penetration into the skin. In this research, CHL was developed into a bacterially sensitive microparticles which were further incorporated into a microneedle system to increase penetration. To support this formulation, in this study, UV-vis spectrophotometry method was validated in methanol, polyvinyl alcohol (PVA) 1%, phosphate buffered saline (PBS), tryptic soy broth (TSB) (fluid-mimicking infection), and skin tissue to quantify amount of CHL. The developed analytical method was subsequently validated according to ICH guidelines. The results obtained showed that the correlation coefficients were linear ≥0.9934. The values of LLOQ inside the methanol, PVA 1%, PBS, TSB, and skin tissue were 7.20 µg/mL, 4.40 µg/mL, 8.18 µg/mL, 387.48 µg/mL, and 7.27 µg/mL, respectively. The accuracy and precision of the developed method were prominent. These methods were successfully applied to quantify the amount of CHL in microparticle and microneedle system in fluid and tissue skin infection. The result showed the high drug release microparticle sensitive bacteria, and high drug retention in ex vivo dermatokinetic evaluation in rat skin tissue containing bacterial infection. This was due to the presence of Staphylococcus aureus bacteria culture that produced lipase enzymes, playing a role in lysing microparticle matrix to develop selectively delivery antimicrobials. A further analytical method needs to be matured to quantify CHL inside the in vivo studies.

Dissolvable sodium alginate-based antibacterial wound dressing patches: Design, characterization, and in vitro biological studies

The treatment of infected wounds in patients with highly sensitive skin is challenging. Some of the available wound dressings cause further skin tear and bleeding upon removal thereby hindering the healing process. In this study, dissolvable antibacterial wound dressing patches loaded with cephalexin monohydrate were prepared from different amounts of sodium alginate (SA) and carboxymethyl cellulose (CMC) by the solvent casting evaporation technique. The patches displayed good tensile strength (3.83-13.83 MPa), appropriate thickness (0.09 to 0.31 mm) and good flexibility (74-98 %) suitable for the skin. The patches displayed good biodegradability and low moisture uptake suitable to prevent microbial invasion on the wound dressings upon storage. The release profile of the drug from the patches was sustained in the range of 47-80 % for 48 h, revealing their capability to inhibit bacterial infection. The biological assay showed that the patches did not induce cytotoxic effects on HaCaT cells, revealing good biocompatibility. The antimicrobial effect of the patches on the different strains of bacteria used in the study was significant. The cell migration (66.7-74.3 %) to the scratched gap was promising revealing the patches' capability to promote wound closure. The results obtained show that the wound dressings are potential materials for the treatment of infected wounds.

Solid lipid nanoparticles cyclodextrin-decorated incorporated into gellan gum-based dry floating in situ delivery systems for controlled release of bioactive compounds of safflower (Carthamus tinctorius. L): A proof of concept study in biorelevant media

Safflower (Carthamus tinctorius L.) has been explored as a source of natural antioxidant. However, quercetin 7-O-beta-D-glucopyranoside and luteolin 7-O-beta-D-glucopyranoside, as its bioactive compounds, possessed poor aqueous solubility, limiting its efficacy. Here, we developed solid lipid nanoparticles (SLNs) decorated with hydroxypropyl beta-cyclodextrin (HPβCD) incorporated into dry floating gel in situ systems to control the release of both compounds. Using Geleol® as a lipid matrix, SLNs were <200 nm in size with >80 % of encapsulation efficiency. Importantly, following the decoration using HPβCD, the stability of SLNs in gastric environment was significantly improved. Furthermore, the solubility of both compounds was also enhanced. The incorporation of SLNs into gellan gum-based floating gel in situ provided desired flow and floating properties, with <30 s gelation time. The floating gel in situ system could control the release of bioactive compounds in FaSSGF (Fasted-State Simulated Gastric Fluid). Furthermore, to assess the effect of food intake on release behavior, we found that the formulation could show a sustained release pattern in FeSSGF (Fed-State Simulated Gastric Fluid) for 24 h after being released in FaSGGF for 2 h. This indicated that this combination approach could be a promising oral delivery for bioactive compounds in safflower.

Smart microneedle patches for wound healing and management

The number of patients with non-healing wounds is generally increasing globally, placing a huge social and economic burden on every country. The complexity of the wound-healing process remains a major health challenge despite the numerous studies that have been reported on conventional wound dressings. Therefore, a therapeutic system that combines diagnostic and therapeutic modalities is essential to monitor wound-related biomarkers and facilitate wound healing in real time. Microneedles, as a multifunctional platform, are promising for transdermal diagnostics and drug delivery. Their advantages are mainly reflected in painless transdermal drug delivery, good biocompatibility, and ease of self-administration. In this work, we review recent advances in the use of microneedle patches for wound healing and monitoring. The paper first provides a brief overview of the skin structure and the wound healing process, and then discusses the current state of research and prospects for the development of wound-related biomarkers and their real-time monitoring based on microneedle sensors. It summarizes the current state of research based on the unique design of microneedle patches, including biomimetic, conductive, and environmentally responsive, to achieve wound healing. It further summarizes the prospects for the application of different microneedle-based drug delivery modalities and drug delivery substances for wound healing, due to their superior transdermal drug delivery advantages. It concludes with challenges and expectations for the use of smart microneedle patches for wound healing and management.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Role of wound microbiome, strategies of microbiota delivery system and clinical management

Delayed wound healing is one of the most global public health threats affecting nearly 100 million people each year, particularly the chronic wounds. Many confounding factors such as aging, diabetic disease, medication, peripheral neuropathy, immunocompromises or arterial and venous insufficiency hyperglycaemia are considered to inhibit wound healing. Therapeutic approaches for slow wound healing include anti-infection, debridement and the use of various wound dressings. However, the current clinical outcomes are still unsatisfied. In this review, we discuss the role of skin and wound commensal microbiota in the different healing stages, including inflammation, cell proliferation, re-epithelialization and remodelling phase, followed by multiple immune cell responses to commensal microbiota. Current clinical management in treating surgical wounds and chronic wounds was also reviewed together with potential controlled delivery systems which may be utilized in the future for the topical administration of probiotics and microbiomes. This review aims to introduce advances, novel strategies, and pioneer ideas in regulating the wound microbiome and the design of controlled delivery systems.

Therapeutic application of carvacrol: A comprehensive review

Carvacrol is a major natural constituent and is significantly present as an essential oil in aromatic plants and is well known for its numerous biological activities. Therapeutic properties of carvacrol have been demonstrated as anti-oxidant, anticancer, diabetes prevention, cardioprotective, anti-obesity, hepatoprotective and reproductive role, antiaging, antimicrobial, and immunomodulatory properties. The carvacrol biosynthesis has been mediated through mevalonate pathway. Carvacrol has the anticancer ability against malignant cells via decreasing the expressions of matrix metalloprotease 2 and 9, inducing apoptosis, enhancing the expression of pro-apoptotic proteins, disrupting mitochondrial membrane, suppressing extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase signal transduction, and also decreasing the phosphoinositide 3-kinase/protein kinase B. It also decreased the concentrations of alanine aminotransferase, alkaline phosphatase and aspartate aminotransferase, and gamma-glutamyl transpeptidase as well as also restored liver function, insulin level, and plasma glucose level. Carvacrol also has been found to exert antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Coagulase-negative staphylococcus, Salmonella spp., Enterococcus sp. Shigella, and Escherichia coli. The current review article summarizes the health-promoting perspectives of carvacrol through various pathways.

Stimuli-responsive therapeutic systems for the treatment of diabetic infected wounds

Diabetic wound infection is a common disease that has significantly reduced people's quality of life. Although tremendous achievements have been made in clinical treatment, the crucial challenge in diabetic infected wound management stems from the detrimental diabetic wound environment and the emergence of bacterial resistance after long-term medication, which result in a reduced efficacy, an increased dosage of medication, and severe side effects. To tackle these issues, it is of great significance to develop an innovative treatment strategy for diabetic wound infection therapy. Currently, the exploitation of nanobiomaterial-based therapeutic systems for diabetic infected wounds is booming, and therapeutic systems with a stimuli-responsive performance have received extensive attention. These therapeutic systems are able to accelerate diabetic infected wound healing due to the on-demand release of therapeutic agents in diabetic infected wounds in response to stimulating factors. Based on the characteristics of diabetic infected wounds, many endogenous stimuli-responsive (e.g., glucose, enzyme, hypoxia, and acidity) therapeutic systems have been employed for the targeted treatment of infected wounds in diabetic patients. Additionally, exogenous stimulants, including light, magnetism, and temperature, are also capable of achieving on-demand drug release and activation. In this review, the characteristics of diabetic infected wounds are presented, and then exogenous/endogenous stimuli therapeutic systems for the treatment of diabetic infected wounds are summarized. Finally, the current challenges and future outlook of stimuli-responsive therapeutic systems are also discussed.

Dissolving microneedles with antibacterial functionalities: A systematic review of laboratory studies

Dissolving microneedles (MN) with enhanced physiochemical properties are generating considerable interest as antibacterial delivery devices, which minimize hazardous sharp wastes, injuries, and transmission of blood-borne pathogens. This systematic review demonstrates and analyzes the current state of dissolvable antibacterial MN to establish their efficacy, and the effect of biomaterials selection on their final properties. A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three electronic databases Pubmed, Google scholar, and Scopus were explored for peer-reviewed articles. A total of 551 results with 176 citations and 915 references of resulted articles were reviewed and analyzed. No publication date restrictions were imposed. Last search was placed on 9th of June, 2021. The literature search in electronic databases according to the inclusion criteria was funneled down to 20 papers that were related to antibacterial effects of dissolving microneedles. In conclusion, all included dissolving MN studies presented an enhanced or at least an equal antibacterial activity against common bacterial species when compared to conventional treatments. In addition, composition modifications can enhance their activity and performance. Other factors such as the size and geometry of the produced MN can be tailored to conform to the infected site's characteristics.

Biogenic Silver Nanoparticles Strategically Combined With Origanum vulgare Derivatives: Antibacterial Mechanism of Action and Effect on Multidrug-Resistant Strains

Multidrug-resistant bacteria have become a public health problem worldwide, reducing treatment options against several pathogens. If we do not act against this problem, it is estimated that by 2050 superbugs will kill more people than the current COVID-19 pandemic. Among solutions to combat antibacterial resistance, there is increasing demand for new antimicrobials. The antibacterial activity of binary combinations containing bioAgNP (biogenically synthesized silver nanoparticles using Fusarium oxysporum), oregano essential oil (OEO), carvacrol (Car), and thymol (Thy) was evaluated: OEO plus bioAgNP, Car plus bioAgNP, Thy plus bioAgNP, and Car plus Thy. This study shows that the mechanism of action of Thy, bioAgNP, and Thy plus bioAgNP involves damaging the membrane and cell wall (surface blebbing and disruption seen with an electron microscope), causing cytoplasmic molecule leakage (ATP, DNA, RNA, and total proteins) and oxidative stress by enhancing intracellular reactive oxygen species and lipid peroxidation; a similar mechanism happens for OEO and Car, except for oxidative stress. The combination containing bioAgNP and oregano derivatives, especially thymol, shows strategic antibacterial mechanism; thymol disturbs the selective permeability of the cell membrane and consequently facilitates access of the nanoparticles to bacterial cytoplasm. BioAgNP-treated Escherichia coli developed resistance to nanosilver after 12 days of daily exposition. The combination of Thy and bioAgNP prevented the emergence of resistance to both antimicrobials; therefore, mixture of antimicrobials is a strategy to extend their life. For antimicrobials alone, minimal bactericidal concentration ranges were 0.3-2.38 mg/ml (OEO), 0.31-1.22 mg/ml (Car), 0.25-1 mg/ml (Thy), and 15.75-31.5 μg/ml (bioAgNP). The time-kill assays showed that the oregano derivatives acted very fast (at least 10 s), while the bioAgNP took at least 30 min to kill Gram-negative bacteria and 7 h to kill methicillin-resistant Staphylococcus aureus (MRSA). All the combinations resulted in additive antibacterial effect, reducing significantly minimal inhibitory concentration and acting faster than the bioAgNP alone; they also showed no cytotoxicity. This study describes for the first time the effect of Car and Thy combined with bioAgNP (produced with F. oxysporum components) against bacteria for which efficient antimicrobials are urgently needed, such as carbapenem-resistant strains (E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) and MRSA.

Emerging trends in microneedle-based drug delivery strategies for the treatment of rheumatoid arthritis

INTRODUCTION

The current drug therapies for treating Rheumatoid Arthritis (RA) include NSAIDs, DMARDs, or biological products designed to mitigate the symptoms of the disease. These therapies with conventional delivery systems possess limitations such as lack of selectivity and adverse effects in the extra-articular tissues. Microneedles-based transdermal drug delivery gained huge attention that can overcome the limitations associated with conventional preparations.

AREAS COVERED

This review aims to provide detailed information on types of Microneedles (MNs) and their usage in drug delivery for the management of Rheumatoid Arthritis. In addition, it also provides evidence for the effective use of MNs in RA treatment. Various types of MNs, their regulatory status, clinical trials and patents are also compiled in this review.

EXPERT OPINION

Microneedles are small patch-like structures consisting of needles in micron range arranged in array-like structure, used to manage drugs designed to be given via transdermal route. Microneedles provide painless delivery, fast onset of action, bypass the first-pass metabolism and be easily self-administered. In the case of RA treatment, which requires a long-term application of drugs, MNs is a new and emerging way to ease the symptoms of RA.

Stimuli-Responsive Microneedles as a Transdermal Drug Delivery System: A Demand-Supply Strategy

Microneedles are one of the most prominent approaches capable of physically disrupting the stratum corneum without devastating the deeper tissues to deliver both small molecules and macromolecules into the viable epidermis/dermis for local/systemic effects. Over the past two decades, microneedles have caught the attention of many researchers because of their outstanding advantages over oral and parenteral drug delivery systems such as self-administration, pain-free, steady-plasma concentration maintenance, avoidance of first-pass hepatic biotransformation, and so on. So far, scientists have reported various types of microneedle patches to deliver the loaded therapeutics as soon as the microneedles are inserted into the skin, regardless of the demand for therapeutics to treat a specific condition. This way of drug delivery can lead to potential risks such as poor therapeutic efficacy or drug overdose. The stimuli-responsive microneedles are the most predominant tool to achieve the on-demand/need-based drug delivery, leading to safe and effective treatment. Various natural and synthetic polymers that can undergo significant transitions such as swelling, shrinking, dissolution, or disintegration play a pivotal role in the development of stimuli-responsive microneedles. The current Review provides brief information about the history, emergence, type, and working principles of microneedles. Furthermore, it selectively discusses various exogenous and endogenous stimuli-responsive microneedles along with their mechanism of action involved in treating different disease conditions. Collaterally, the emergence of "closed-loop" combinatorial stimuli-responsive microneedle patches for precise delivery of therapeutics is meticulously canvassed. Subsequently, it covers the patents of different stimuli-responsive microneedles and further highlights the existing challenges and future perspectives concerning clinical application and large-scale production.

Nano-Antibacterials Using Medicinal Plant Components: An Overview

Gradual emergence of new bacterial strains, resistant to one or more antibiotics, necessitates development of new antibacterials to prevent us from newly evolved disease-causing, drug-resistant, pathogenic bacteria. Different inorganic and organic compounds have been synthesized as antibacterials, but with the problem of toxicity. Other alternatives of using green products, i.e., the medicinal plant extracts with biocompatible and potent antibacterial characteristics, also had limitation because of their low aqueous solubility and therefore less bioavailability. Use of nanotechnological strategy appears to be a savior, where phytochemicals are nanonized through encapsulation or entrapment within inorganic or organic hydrophilic capping agents. Nanonization of such products not only makes them water soluble but also helps to attain high surface to volume ratio and therefore high reaction area of the nanonized products with better therapeutic potential, over that of the equivalent amount of raw bulk products. Medicinal plant extracts, whose prime components are flavonoids, alkaloids, terpenoids, polyphenolic compounds, and essential oils, are in one hand nanonized (capped and stabilized) by polymers, lipids, or clay materials for developing nanodrugs; on the other hand, high antioxidant activity of those plant extracts is also used to reduce various metal salts to produce metallic nanoparticles. In this review, five medicinal plants, viz., tulsi (Ocimum sanctum), turmeric (Curcuma longa), aloe vera (Aloe vera), oregano (Oregano vulgare), and eucalyptus (Eucalyptus globulus), with promising antibacterial potential and the nanoformulations associated with the plants' crude extracts and their respective major components (eugenol, curcumin, anthraquinone, carvacrol, eucalyptus oil) have been discussed with respect to their antibacterial potency.