Transdermal microarrayed electroporation for enhanced cancer immunotherapy based on DNA vaccination.

Despite the tremendous clinical potential of nucleic acid-based vaccines, their efficacy to induce therapeutic immune response has been limited by the lack of efficient local gene delivery techniques in the human body. In this study, we develop a hydrogel-based organic electronic device (µEPO) for both transdermal delivery of nucleic acids and in vivo microarrayed cell electroporation, which is specifically oriented toward one-step transfection of DNAs in subcutaneous antigen-presenting cells (APCs) for cancer immunotherapy. The µEPO device contains an array of microneedle-shaped electrodes with pre-encapsulated dry DNAs. Upon a pressurized contact with skin tissue, the electrodes are rehydrated, electrically triggered to release DNAs, and then electroporate nearby cells, which can achieve in vivo transfection of more than 50% of the cells in the epidermal and upper dermal layer. As a proof-of-concept, the µEPO technique is employed to facilitate transdermal delivery of neoantigen genes to activate antigen-specific immune response for enhanced cancer immunotherapy based on a DNA vaccination strategy. In an ovalbumin (OVA) cancer vaccine model, we show that high-efficiency transdermal transfection of APCs with OVA-DNAs induces robust cellular and humoral immune responses, including antigen presentation and generation of IFN-γ+ cytotoxic T lymphocytes with a more than 10-fold dose sparing over existing intramuscular injection (IM) approach, and effectively inhibits tumor growth in rodent animals.

A novel anti-pruritic: Topical co-administration of high molecular weight hyaluronan (HMWH) with protamine, a transdermal transport enhancer.

Pruritis, the sensation of itch, is produced by multiple substances, exogenous and endogenous, that sensitizes specialized sensory neurons (pruriceptors and pruri-nociceptors). Unfortunately, many patients with acute and chronic pruritis obtain only partial relief when treated with currently available treatment modalities. We recently demonstrated that the topical application of high molecular weight hyaluronan (HMWH), when combined with vehicles containing transdermal transport enhancers, produce potent long-lasting reversal of nociceptor sensitization associated with inflammatory and neuropathic pain. In the present experiments we tested the hypothesis that the topical formulation of HMWH with protamine, a transdermal transport enhancer, can also attenuate pruritis. We report that this topical formulation of HMWH markedly attenuates scratching behavior at the nape of the neck induced by serotonin (5-hydroxytryptamine, 5-HT), in male and female rats. Our results support the hypothesis that topical HMWH in a transdermal transport enhancer vehicle is a strong anti-pruritic.

Smart Physical-Based Transdermal Drug Delivery System:Towards Intelligence and Controlled Release.

Transdermal drug delivery systems based on physical principles have provided a stable, efficient, and safe strategy for disease therapy. However, the intelligent device with real-time control and precise drug release is required to enhance treatment efficacy and improve patient compliance. This review summarizes the recent developments, application scenarios, and drug release characteristics of smart transdermal drug delivery systems fabricated with physical principle. Special attention is paid to the progress of intelligent design and concepts in of physical-based transdermal drug delivery technologies for real-time monitoring and precise drug release. In addition, facing with the needs of clinical treatment and personalized medicine, the recent progress and trend of physical enhancement are further highlighted for transdermal drug delivery systems in combination with pharmaceutical dosage forms to achieve better transdermal effects and facilitate the development of smart medical devices. Finally, the next generation and future application scenarios of smart physical-based transdermal drug delivery systems are discussed, a particular focus in vaccine delivery and tumor treatment.

Transdermal Microneedles Alleviated Rheumatoid Arthritis by Inducing Immune Tolerance via Skin-Resident Antigen Presenting Cells.

Restoring immune tolerance is the ultimate goal for rheumatoid arthritis (RA) treatment. The most reported oral or intravenous injection routes for the immunization of autoantigens cause gastrointestinal side effects, low patient compliance, and unsatisfied immune tolerance induction. Herein, the use of a transdermal microneedle patch is for the first time investigated to codeliver CII peptide autoantigen and rapamycin for reversing immune disorders of RA. The immunized microneedles efficiently recruit antigen-presenting cells particularly Langerhans cells, and induce tolerogenic dendritic cells at the administration skin site. The tolerogenic dendritic cells further homing to lymph nodes to activate systemic Treg cell differentiation, which upregulates the expression of anti-inflammatory mediators while inhibiting the polarization of Th1/2 and Th17 T cell phenotypes and the expression of inflammatory profiles. As a result, the optimized microneedles nearly completely eliminate RA symptoms and inflammatory infiltrations. Furthermore, it is demonstrated that a low dose of rapamycin is crucial for the successful induction of immune tolerance. The results indicate that a rationally designed microneedle patch is a promising strategy for immune balance restoration with increased immune tolerance induction efficiency and patient compliance.

Recent advances in delivery of transdermal nutrients: A review.

Nutrients provide vital functions in the body for sustained health, which have been shown to be related to the incidence, prevention and treatment of disease. However, limited bioavailability, loss of targeting specificity and the increased hepatic metabolism limit the utilization of nutrients. In this review, we highlight transdermal absorption of nutrients, which represents an opportunity to allow great use of many nutrients with promising human health benefits. Moreover, we describe how the various types of permeation enhancers are increasingly exploited for transdermal nutrient delivery. Chemical penetration enhancers, carrier systems and physical techniques for transdermal nutrient delivery are described, with a focus on combinatorial approaches. Although there are many carrier systems and physical techniques currently in development, with some tools currently in advanced clinical trials, relatively few products have achieved full translation to clinical practice. Challenges and further developments of these tools are discussed here in this review. This review will be useful to researchers interested in transdermal applications of permeation enhancers for the efficient delivery of nutrients, providing a reference for supporting the need to take more account of specific nutritional needs in specific states.

Prolonged administration of the granisetron transdermal delivery system reduces capecitabine plus oxaliplatin regimen induced nausea and vomiting.

OBJECTIVE: To evaluate the safety and efficacy of the granisetron transdermal delivery system (GTDS) combined with Dexamethasone for preventing chemotherapy-induced nausea and vomiting (CINV) in patients receiving Capecitabine plus Oxaliplatin (CapeOX) therapy. DESIGN: Open-label, prospective, multi-center phase II trial. SETTING: Three institutions. PARTICIPANTS: Fifty-four patients scheduled to receive CapeOX chemotherapy. INTERVENTIONS: Participants received GTDS (3.1 mg applied to the upper arm 48 h before chemotherapy, replaced on day 5, and discarded on day 12) and Dexamethasone. MAIN OUTCOME MEASURES: The primary endpoint was the complete control rate of CINV. Secondary endpoints included the duration of delayed complete control, complete control rate in the acute phase, safety, and quality of life. RESULTS: The complete control rate for delayed CINV over the entire period (25-480 h) was 72.7% (95% CI 0.57-0.88). The duration of delayed complete control was 17.2 ± 4.5 days, with 51.5% of patients experiencing no nausea during the delayed phase. The complete control rate in the acute phase was 81.8% (95% CI 0.69-0.95). No serious adverse events related to the antiemetic regimen were reported. CONCLUSION: Prolonged administration of GTDS is safe and effective for preventing CINV in patients with gastrointestinal malignancies treated with CapeOX. TRIAL REGISTRATION: ClinicalTrials.gov registry (NCT05325190); registered on October 10, 2021.

Fabrication of lidocaine-loaded polymer dissolving microneedles for rapid and prolonged local anesthesia.

There is an urgent need for research into effective interventions for pain management to improve patients' life quality. Traditional needle and syringe injection were used to administer the local anesthesia. However, it causes various discomforts, ranging from brief stings to trypanophobia and denial of medical operations. In this study, a dissolving microneedles (MNs) system made of composite matrix materials of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and sodium hyaluronate (HA) was successfully developed for the loading of lidocaine hydrochloride (LidH). The morphology, size and mechanical properties of the MNs were also investigated. After the insertion of MNs into the skin, the matrix at the tip of the MNs was swelled and dissolved by absorption of interstitial fluid, leading to a rapid release of loaded LidH from MNs' tips. And the LidH in the back patching was diffused into deeper skin tissue through microchannels created by MNs insertion, forming a prolonged anesthesia effect. In addition, the back patching of MNs could be acted as a drug reservoir to form a prolonged local anesthesia effect. The results showed that LidH MNs provided a superior analgesia up to 8 h, exhibiting a rapid and long-lasting analgesic effects. Additionally, tissue sectioning and in vitro cytotoxicity tests indicated that the MNs patch we developed had a favorable biosafety profile.

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

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

Transdermal Delivery of Pramipexole Using Microneedle Technology for the Potential Treatment of Parkinson's Disease.

Parkinson's disease (PD) is a debilitating neurodegenerative disease primarily impacting neurons responsible for dopamine production within the brain. Pramipexole (PRA) is a dopamine agonist that is currently available in tablet form. However, individuals with PD commonly encounter difficulties with swallowing and gastrointestinal motility, making oral formulations less preferable. Microneedle (MN) patches represent innovative transdermal drug delivery devices capable of enhancing skin permeability through the creation of microconduits on the surface of the skin. MNs effectively reduce the barrier function of skin and facilitate the permeation of drugs. The work described here focuses on the development of polymeric MN systems designed to enhance the transdermal delivery of PRA. PRA was formulated into both dissolving MNs (DMNs) and directly compressed tablets (DCTs) to be used in conjunction with hydrogel-forming MNs (HFMNs). In vivo investigations using a Sprague-Dawley rat model examined, for the first time, if it was beneficial to prolong the application of DMNs and HFMNs beyond 24 h. Half of the patches in the MN cohorts were left in place for 24 h, whereas the other half remained in place for 5 days. Throughout the entire 5 day study, PRA plasma levels were monitored for all cohorts. This study confirmed the successful delivery of PRA from DMNs (Cmax = 511.00 ± 277.24 ng/mL, Tmax = 4 h) and HFMNs (Cmax = 328.30 ± 98.04 ng/mL, Tmax = 24 h). Notably, both types of MNs achieved sustained PRA plasma levels over a 5 day period. In contrast, following oral administration, PRA remained detectable in plasma for only 48 h, achieving a Cmax of 159.32 ± 113.43 ng/mL at 2 h. The HFMN that remained in place for 5 days demonstrated the most promising performance among all investigated formulations. Although in the early stages of development, the findings reported here offer a hopeful alternative to orally administered PRA. The sustained plasma profile observed here has the potential to reduce the frequency of PRA administration, potentially enhancing patient compliance and ultimately improving their quality of life. This work provides substantial evidence advocating the development of polymeric MN-mediated drug delivery systems to include sustained plasma levels of hydrophilic pharmaceuticals.

Biological Fate Tracking of Nitric Oxide-Propelled Microneedle Delivery System Using an Aggregation-Caused Quenching Probe.

Nanoparticle-loaded dissolving microneedles (DMNs) have attracted increasing attention due to their ability to provide high drug loading, adjustable drug release behavior, and enhanced therapeutic efficiency. However, such delivery systems still face unsatisfied drug delivery efficiency due to insufficient driving force to promote nanoparticle penetration and the lack of in vivo fate studies to guide formulation design. Herein, an aggregation-caused quenching (ACQ) probe (P4) was encapsulated in l-arginine (l-Arg)-based nanomicelles, which was further formulated into nitric oxide (NO)-propelled nanomicelle-integrated DMNs (P4/l-Arg NMs@DMNs) to investigate their biological fate. The P4 probe could emit intense fluorescence signals in intact nanomicelles, while quenching with the dissociation of nanomicelles, providing a "distinguishable" method for tracking the fate of nanomicelles at a different status. l-Arg was demonstrated to self-generate NO under the tumor microenvironment with excessive reactive oxygen species (ROS), providing a pneumatic force to promote the penetration of nanomicelles in both three-dimensional (3D)-cultured tumor cells and melanoma-bearing mice. Compared with passive microneedles (P4 NMs@DMNs) without a NO propellant, the P4/l-Arg NMs@DMNs possessed a good NO production performance and higher nanoparticle penetration capacity. In conclusion, this study offered an ACQ probe-based biological fate tracking approach to demonstrate the potential of NO-propelled nanoparticle-loaded DMNs in penetration enhancement for topical tumor therapy.

Fabrication of Hybrid Coated Microneedles with Donepezil Utilizing Digital Light Processing and Semisolid Extrusion Printing for the Management of Alzheimer's Disease.

Microneedle (MN) patches are gaining increasing attention as a cost-effective technology for delivering drugs directly into the skin. In the present study, two different 3D printing processes were utilized to produce coated MNs, namely, digital light processing (DLP) and semisolid extrusion (SSE). Donepezil (DN), a cholinesterase inhibitor administered for the treatment of Alzheimer's disease, was incorporated into the coating material. Physiochemical characterization of the coated MNs confirmed the successful incorporation of donepezil as well as the stability and suitability of the materials for transdermal delivery. Optical microscopy and SEM studies validated the uniform weight distribution and precise dimensions of the MN arrays, while mechanical testing ensured the MNs' robustness, ensuring efficient skin penetration. In vitro studies were conducted to evaluate the produced transdermal patches, indicating their potential use in clinical treatment. Permeation studies revealed a significant increase in DN permeation compared to plain coating material, affirming the effectiveness of the MNs in enhancing transdermal drug delivery. Confocal laser scanning microscopy (CLSM) elucidated the distribution of the API, within skin layers, demonstrating sustained drug release and transcellular transport pathways. Finally, cell studies were also conducted on NIH3T3 fibroblasts to evaluate the biocompatibility and safety of the printed objects for transdermal applications.

Transdermal oestradiol and exercise in androgen deprivation therapy (ESTRACISE): protocol.

OBJECTIVE: To report the protocol of a study evaluating the efficacy of transdermal oestradiol (E2) gel in reducing the adverse effects of androgen deprivation therapy (ADT), specifically on sexual function, and to assess the utility of E2 in combination with supervised exercise. STUDY DESIGN AND METHODS: The primary endpoint of this open-label Phase IIA randomized controlled trial is the efficacy of transdermal E2 gel. Secondary endpoints include: (i) the occurrence of ADT-induced adverse effects; (ii) the safety and tolerability of E2; (iii) the impact of E2 with or without exercise on physical, physiological, muscle, and systemic biomarkers; and (iv) quality of life. The trial will recruit high-risk PCa patients (n = 310) undergoing external beam radiation therapy with adjuvant subcutaneous ADT. Participants will be stratified and randomized in a 1:1 ratio to either the E2 + ADT arm or the ADT-only control arm. Additionally, a subset of patients (n = 120) will be randomized into a supervised exercise programme. RESULTS: The primary outcome is assessed according to the efficacy of E2 in mitigating the deterioration of Expanded Prostate Cancer Index Composite sexual function domain scores. Secondary outcomes are assessed according to the occurrence of ADT-induced adverse effects, safety and tolerability of E2, impact of E2 with or without exercise on physical performance, body composition, bone mineral density, muscle size, systematic biomarkers, and quality of life. CONCLUSION: The ESTRACISE study's innovative design can offer novel insights about the benefits of E2 gel, and the substudy can reinforce the benefits resistance training and deliver valuable new novel insights into the synergistic benefits of E2 gel and exercise, which are currently unknown. TRIAL REGISTRATION: The protocol has been registered in euclinicaltrials.eu (2023-504704-28-00) and in clinicaltrials.gov (NCT06271551).

Revisiting the Effect of Aging on the Transport of Molecules through the Skin.

Both intrinsic and extrinsic aging lead to a series of morphological changes in the skin including the flattening of the dermal-epidermal junction, increased stratum corneum dryness, reduction in sebaceous gland activity and enzyme activity as well as atrophy of blood vessels. In this study, the impact of these changes on the transport of molecules through the skin was revised. The increase in the number of transdermal formulations on the market in recent decades and life expectancy represent the main reasons for an in-depth discussion of this topic. Furthermore, elderly subjects have often been excluded from clinical trials due to polypharmacy, raising concerns in terms of efficacy and safety. In this way, ex vivo and in vivo studies comparing the transport of molecules through the mature and young skin were analyzed in detail. The reduced water content in mature skin had a significant impact on the transport rate of hydrophilic molecules. The lower enzymatic activity in aged skin, in turn, would explain changes in the activation of prodrugs. Interestingly, greater deposition of nanoparticles was also found in mature skin. In vivo models should be prioritized in future experimental studies as they allow to evaluate both absorption and metabolism simultaneously, providing more realistic information.

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.

Fabrication and Characterization of Dissolving Microneedles for Transdermal Drug Delivery of Apomorphine Hydrochloride in Parkinson's Disease.

PURPOSE: We fabricated and characterized polyvinyl alcohol (PVA)-based dissolving microneedles (MNs) for transdermal drug delivery of apomorphine hydrochloride (APO), which is used in treating the wearing-off phenomenon observed in Parkinson's disease. METHODS: We fabricated MN arrays with 11 × 11 needles of four different lengths (300, 600, 900, and 1200 µm) by micromolding. The APO-loaded dissolving MNs were characterized in terms of their physicochemical and functional properties. We also compared the pharmacokinetic parameters after drug administration using MNs with those after subcutaneous injection by analyzing the blood concentration of APO in rats. RESULTS: PVA-based dissolving MNs longer than 600 µm could effectively puncture the stratum corneum of the rat skin with penetrability of approximately one-third of the needle length. Although APO is known to have chemical stability issues in aqueous solutions, the drug content in APO-loaded MNs was retained at 25°C for 12 weeks. The concentration of APO after the administration of APO-loaded 600-µm MNs that dissolved completely in skin within 60 min was 81%. The absorption of 200-µg APO delivered by MNs showed a Tmax of 20 min, Cmax of 76 ng/mL, and AUC0-120 min of 2,829 ng・min/mL, compared with a Tmax of 5 min, Cmax of 126 ng/mL, and AUC0-120 min of 3,224 ng・min/mL for subcutaneous injection. The bioavailability in terms of AUC0-120 min of APO delivered by MNs was 88%. CONCLUSION: APO-loaded dissolving MNs can deliver APO via skin into the systemic circulation with rapid absorption and high bioavailability.

A Hollow Microneedle Equipped with a Micropillar for Improved Needle Insertion and Injection of Drug Solution.

PURPOSE: Hollow-type microneedles (hMNs) are a promising device for the effective administration of drugs into intradermal sites. Complete insertion of the needle into the skin and administration of the drug solution without leakage must be achieved to obtain bioavailability or a constant effect. In the present study, several types of hMN with or without a rounded blunt tip micropillar, which suppresses skin deformation, around a hollow needle, and the effect on successful needle insertion and administration of a drug solution was investigated. Six different types of hMNs with needle lengths of 1000, 1300, and 1500 µm with or without a micropillar were used. METHODS: Needle insertion and the disposition of a drug in rat skin were investigated. In addition, the displacement-force profile during application of hMNs was also investigated using a texture analyzer with an artificial membrane to examine needle factors affecting successful insertion and administration of a drug solution by comparing with in vivo results. RESULTS: According to the results with the drug distribution of iodine, hMN1300 with a micropillar was able to successfully inject drug solution into an intradermal site with a high success rate. In addition, the results of displacement-force profiles with an artificial membrane showed that a micropillar can be effective for depth control of the injected solution as well as the prevention of contact between the hMN pedestal and the deformed membrane. CONCLUSION: In the present study, hMN1300S showed effective solution delivery into an intradermal site. In particular, a micropillar can be effective for depth control of the injected solution as well as preventing contact between the hMN pedestal and the deformed membrane. The obtained results will help in the design and development of hMNs that ensure successful injection of an administered drug.

Transdermal Opioids and the Quality of Life of the Cancer Patient: A Systematic Literature Review.

OBJECTIVE: This systematic literature review aims to evaluate the effectiveness of transdermal opioids in managing cancer pain and their impact on the quality of life (QoL) of patients. DATA SOURCES: A systematic literature review conducted following the PRISMA protocol, focusing on randomized clinical trials found in the Lilacs, Embase, PubMed, and SciELO databases over the last 20 years. STUDY SELECTION AND DATA EXTRACTION: We included randomized clinical trials, published in English, Portuguese, or Spanish, which assessed the impact of transdermal opioids on the QoL. Data extraction was facilitated using the Rayyan app. DATA SYNTHESIS: Six articles meeting the inclusion and exclusion criteria were analyzed. These studies covered a population ranging from 24 to 422 cancer patients experiencing moderate to severe pain. The risk of bias was assessed in each study, generally being categorized as uncertain or high. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: The findings indicate that the analgesic effectiveness and side effects of transdermal formulations (specifically buprenorphine and fentanyl) for managing moderate to severe cancer pain are comparable to, or in some cases superior to, those of oral opioids traditionally employed. CONCLUSIONS: Transdermal therapy was suggested to have several advantages over oral opioid therapy in enhancing cancer patients' QoL. These benefits span various dimensions, including pain management, physical functioning, mental health, vitality, overall patient improvement, anger/aversion, strength/activity, general QoL, cognitive and emotional functions, fatigue, and insomnia.

Improved efficacy of linear glutathione-peptide chaperon complexes on melanogenesis inhibition and transdermal delivery.

Glutathione (GSH) exhibits considerable potential in the cosmetic industry for reducing intracellular tyrosinase activity and inhibiting melanin synthesis. However, its efficacy is hindered by limited permeability, restricting its ability to reach the basal layer of the skin where melanin production occurs. The transdermal enhancer peptide TD1 has emerged as a promising strategy to facilitate the transdermal transfer of proteins or peptides by creating intercellular gaps in keratinocytes, providing access to the basal layer. The primary objective of this study is to enhance the transdermal absorption capacity of GSH while augmenting its inhibitory effect on melanin. Two coupling structures were designed for investigation: linear (TD1-linker-GSH) and branched (TD1-GSH). The study examined the impact of the peptide skeleton on melanin inhibition ability. Our findings revealed that the linear structure not only inhibited synthetic melanin production in B16F10 cells through a direct pathway but also through a paracrine pathway, demonstrating a significant tyrosinase inhibition of nearly 70 %, attributed to the paracrine effect of human keratinocyte HaCaT. In pigmentation models of guinea pigs and zebrafish, the application of TD1-linker-GSH significantly reduced pigmentation. Notably, electric two-photon microscopy demonstrated that TD1-linker-GSH exhibited significant transdermal ability, penetrating 158.67 ± 9.28 µm into the skin of living guinea pigs. Molecular docking analysis of the binding activity with tyrosinase revealed that both TD1-linker-GSH and TD1-GSH occupy the same active pocket, with TD1-linker-GSH binding more tightly to tyrosinase. These results provide a potential foundation for therapeutic approaches aimed at enriched pigmentation and advance our understanding of the mechanisms underlying melanogenesis inhibition.

Molecular design, construction and analgesic mechanism insights into the novel transdermal fusion peptide ANTP-BgNPB.

Toad venom, a traditional Chinese medicine, exhibits remarkable medicinal properties of significant therapeutic value. The peptides present within toad venom possess a wide range of biological functions, yet the neuropeptide B (NPB) and it modification requires further exploration to comprehensively understand its mechanisms of action and potential applications. In this study, a fusion peptide, ANTP-BgNPB, was designed to possess better analgesic properties through the transdermal modification of BgNPB. After optimizing the conditions, the expression of ANTP-BgNPB was successfully induced. The molecular dynamics simulations suggested that the modified protein exhibited improved stability and receptor binding affinity compared to its unmodified form. The analysis of the active site of ANTP-BgNPB and the verification of mutants revealed that GLN3, SER38, and ARG42 were crucial for the protein's recognition and binding with G protein-coupled receptor 7 (GPR7). Moreover, experiments conducted on mice using the hot plate and acetic acid twist body models demonstrated that ANTP-BgNPB was effective in transdermal analgesia. These findings represent significant progress in the development of transdermal delivery medications and could have a significant impact on pain management.

Potent drug delivery enhancement of betulinic acid and NVX-207 into equine skin in vitro - a comparison between a novel oxygen flow-assisted transdermal application device and microemulsion gels.

BACKGROUND: Gray horses are predisposed to equine malignant melanoma (EMM) with advancing age. Depending on the tumor's location and size, they can cause severe problems (e.g., defaecation, urination, feeding). A feasible therapy for EMM has not yet been established and surgical excision can be difficult depending on the location of the melanoma. Thus, an effective and safe therapy is needed. Naturally occurring betulinic acid (BA), a pentacyclic triterpene and its synthetic derivate, NVX-207 (3-acetyl-betulinic acid-2-amino-3-hydroxy-2-hydroxymethyl-propanoate) are known for their cytotoxic properties against melanomas and other tumors and have already shown good safety and tolerability in vivo. In this study, BA and NVX-207 were tested for their permeation potential into equine skin in vitro in Franz-type diffusion cell (FDC) experiments after incubation of 5 min, 30 min and 24 h, aiming to use these formulations for prospective in vivo studies as a treatment for early melanoma stages. Potent permeation was defined as reaching or exceeding the half maximal inhibitory concentrations (IC50) of BA or NVX-207 for equine melanoma cells in equine skin samples. The active ingredients were either dissolved in a microemulsion (ME) or in a microemulsion gel (MEG). All of the formulations were transdermally applied but the oil-in-water microemulsion was administered with a novel oxygen flow-assisted (OFA) applicator (DERMADROP TDA). RESULTS: All tested formulations exceeded the IC50 values for equine melanoma cells for BA and NVX-207 in equine skin samples, independently of the incubation time NVX-207 applied with the OFA applicator showed a significant time-dependent accumulation and depot-effect in the skin after 30 min and 24 h (P < 0.05). CONCLUSIONS: All tested substances showed promising results. Additionally, OFA administration showed a significant accumulation of NVX-207 after 30 min and 24 h of incubation. Further in vivo trials with OFA application are recommended.