Kinetic modeling of the plasma pharmacokinetic profiles of ADAMTS13 fragment and its Fc-fusion counterpart in mice.

Introduction: Fusion of the fragment crystallizable (Fc) to protein therapeutics is commonly used to extend the circulation time by enhancing neonatal Fc-receptor (FcRn)-mediated endosomal recycling and slowing renal clearance. This study applied kinetic modeling to gain insights into the cellular processing contributing to the observed pharmacokinetic (PK) differences between the novel recombinant ADAMTS13 fragment (MDTCS) and its Fc-fusion protein (MDTCS-Fc). Methods: For MDTCS and MDTCS-Fc, their plasma PK profiles were obtained at two dose levels following intravenous administration of the respective proteins to mice. The plasma PK profiles of MDTCS were fitted to a kinetic model with three unknown protein-dependent parameters representing the fraction recycled (FR) and the rate constants for endocytosis (kup, for the uptake into the endosomes) and for the transfer from the plasma to the interstitial fluid (kpi). For MDTCS-Fc, the model was modified to include an additional parameter for binding to FcRn. Parameter optimization was done using the Cluster Gauss-Newton Method (CGNM), an algorithm that identifies multiple sets of approximate solutions ("accepted" parameter sets) to nonlinear least-squares problems. Results: As expected, the kinetic modeling results yielded the FR of MDTCS-Fc to be 2.8-fold greater than that of MDTCS (0.8497 and 0.3061, respectively). In addition, MDTCS-Fc was predicted to undergo endocytosis (the uptake into the endosomes) at a slower rate than MDTCS. Sensitivity analyses identified the association rate constant (kon) between MDTCS-Fc and FcRn as a potentially important factor influencing the plasma half-life in vivo. Discussion: Our analyses suggested that Fc fusion to MDTCS leads to changes in not only the FR but also the uptake into the endosomes, impacting the systemic plasma PK profiles. These findings may be used to develop recombinant protein therapeutics with extended circulation time.

Involvement of the Spinal Serotonergic System in the Analgesic Effect of [6]-Shogaol in Oxaliplatin-Induced Neuropathic Pain in Mice.

Oxaliplatin is a chemotherapy drug that can induce severe acute neuropathy in patients within hours of treatment. In our previous study, 10 mg/kg [6]-shogaol (i.p.) significantly alleviated cold and mechanical allodynia induced by a 6 mg/kg oxaliplatin injection (i.p.); however, the precise serotonin-modulatory effect has not been investigated. In this study, we showed that intrathecal injections of NAN-190 (5-HT1A receptor antagonist, 1 µg) and MDL-72222 (5-HT3 receptor antagonist, 15 µg), but not ketanserin (5-HT2A receptor antagonist, 1 µg), significantly blocked the analgesic effect of [6]-shogaol (10 mg/kg, i.p.). Furthermore, the gene expression of the serotonin-synthesizing enzyme tryptophan hydroxylase 2 (TPH2) and serotonin levels in the spinal cord and serum were significantly downregulated (p < 0.0001 and p = 0.0002) and upregulated (p = 0.0298 and p = 0.0099) after oxaliplatin and [6]-shogaol administration, respectively. Moreover, both the gene and protein expression of the spinal serotonin receptors 5-HT1A and 5-HT3 significantly increased after [6]-shogaol injections (p < 0.0001). Finally, intrathecal injections of both receptor agonists (8-OH-DPAT; 5-HT1A receptor agonist, 10 µg and m-CPBG; 5-HT3 receptor agonist, 15 µg) mimicked the effects of [6]-shogaol in oxaliplatin-injected mice. Taken together, these results demonstrate that [6]-shogaol attenuates oxaliplatin-induced neuropathic pain by modulating the spinal serotoninergic system.

The Effect of Ginger and Its Sub-Components on Pain.

Zingiber officinale Roscoe (ginger) has long been used as an herbal medicine to treat various diseases, and its main sub-components, [6]-gingerol and [6]-shogaol, were also reported to have anti-inflammatory, anti-oxidant, and anti-tumor effects. However, their effects on various types of pain and their underlying mechanisms of action have not been clearly analyzed and understood yet. Thus, in this review, by analyzing 16 studies that used Z. officinale, [6]-gingerol, and [6]-shogaol on mechanical, spontaneous and thermal pain, their effects and mechanisms of action have been analyzed. Pain was induced by either nerve injury or chemical injections in rodents. Nine studies analyzed the analgesic effect of Z. officinale, and four and three studies focused on [6]-gingerol and [6]-shogaol, respectively. Seven papers have demonstrated the underlying mechanism of action of their analgesic effects. Studies have focused on the spinal cord and one on the dorsal root ganglion (DRG) neurons. Involvement and change in the function of serotonergic receptors (5-HT1A, B, D, and 5A), transient receptor potential vanilloid 1 (TRPV1), N-methyl-D-aspartate (NMDA) receptors, phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2), histone deacetylase 1 (HDAC1), voltage-gated sodium channel 1.8 (Nav1.8), substance P (SP), and sciatic nerve's morphology have been observed.

[6]-Shogaol Attenuates Oxaliplatin-Induced Allodynia through Serotonergic Receptors and GABA in the Spinal Cord in Mice.

Although oxaliplatin is a well-known anti-cancer agent used for the treatment of colorectal cancer, treated patients often experience acute cold and mechanical allodynia as side effects. Unfortunately, no optimal treatment has been developed yet. In this study, [6]-shogaol (10 mg/kg, i.p.), which is one of the major bioactive components of Zingiber officinale roscoe (Z. officinale), significantly alleviated allodynia induced by oxaliplatin (6 mg/kg, i.p.) injection. Cold and mechanical allodynia were assessed by acetone drop and von Frey filament tests, respectively. The analgesic effect of [6]-shogaol was blocked by the intrathecal injection of 5-HT1A, 5-HT3, and GABAB receptor antagonists, NAN-190 (1 µg), MDL-72222 (15 µg), and CGP 55845 (10 µg), respectively. Furthermore, oxaliplatin injection lowered the GABA concentration in the superficial laminae of the spinal dorsal horn, whereas [6]-shogaol injection significantly elevated it. The GAD (glutamic acid decarboxylase) 65 concentration also increased after [6]-shogaol administration. However, pre-treatment of NAN-190 completely inhibited the increased GABA induced by [6]-shogaol in the spinal dorsal horn, whereas MDL-72222 partially blocked the effect. Altogether, these results suggest that [6]-shogaol could attenuate oxaliplatin-induced cold and mechanical allodynia through 5-HT1A and 5-HT3 receptor antagonists located in the GABAergic neurons in the spinal dorsal horn in mice.

First-principles study on structural, electronic, magnetic and thermodynamic properties of lithium ferrite LiFe5O8.

Lithium ferrite, LiFe5O8 (LFO), has attracted great attention for various applications, and there has been extensive experimental studies on its material properties and applications. However, no systematic theoretical study has yet been reported, so understanding of its material properties at the atomic scale is still required. In this work, we present a comprehensive investigation into the structural, electronic, magnetic and thermodynamic properties of LFO using first-principles calculations. We demonstrate that the ordered α-phase with ferrimagnetic spin configuration is energetically favourable among various crystalline phases with different magnetic configurations. By applying the DFT + U approach with U = 4 eV, we reproduce the lattice constant, band gap energy, and total magnetization in good agreement with experiments, emphasizing the importance of considering strong correlation and spin-polarization effects originating from the 3d states of Fe atoms. We calculated the phonon dispersions of LFO with ferrimagnetic and non-magnetic states, and subsequently evaluated the Gibbs free energy differences between the two states, plotting the P-T diagram for thermodynamic stability of the ferrimagnetic against non-magnetic state. From the P-T diagram, the Curie temperature is found to be ∼925 K at the normal condition and gradually increase with increasing pressure. Our calculations explain the experimental observations for material properties of LFO, providing a comprehensive understanding of the underlying mechanism and useful guidance for enhancing performance of LFO-based devices.

Superior thermoelectric properties of ternary chalcogenides CsAg5Q3 (Q = Te, Se) predicted using first-principles calculations.

Tailoring novel thermoelectric materials (TEMs) with a high efficiency is challenging due to the difficulty in realizing both low thermal conductivity and high thermopower factor. In this work, we propose ternary chalcogenides CsAg5Q3 (Q = Te, Se) as promising TEMs based on first-principles calculations of their thermoelectric properties. Using lattice dynamics calculations within self-consistent phonon theory, we predict their ultralow lattice thermal conductivities below 0.27 W m-1 K-1, revealing the strong lattice anharmonicity and rattling vibrations of Ag atoms as the main origination. By using the mBJ exchange-correlation functional, we calculate the electronic structures with the direct band gaps in good agreement with experiments, and evaluate the charge carrier lifetime as a function of temperature within the deformation potential theory. Our calculations to solve Boltzmann transport equations demonstrate high thermopower factors of 2.5 mW m-1 K-2 upon p-type doping at 300 K, comparable to the conventional dichalcogenide thermoelectric GeTe. With these ultralow thermal conductivities and high thermopower factors, we determine a relatively high thermoelectric figure of merit ZT along the z-axis, finding the maximum value of ZTz to be 2.5 at 700 K for CsAg5Se3 by optimizing the hole concentration. Our computational results highlight the great potentiality of CsAg5Q3 (Q = Te, Se) for high-performance thermoelectric devices operating at room temperature.

The involvement of the noradrenergic system in the antinociceptive effect of cucurbitacin D on mice with paclitaxel-induced neuropathic pain.

Paclitaxel (sold under the brand name Taxol) is a chemotherapeutic drug that is widely used to treat cancer. However, it can also induce peripheral neuropathy, which limits its use. Although several drugs are used to attenuate neuropathy, no optimal treatment is available to date. In this study, the effect of cucurbitacins B and D on paclitaxel-induced neuropathic pain was assessed. Multiple paclitaxel injections (a cumulative dose of 8 mg/kg, i. p.) induced cold and mechanical allodynia from days 10 to 21 in mice, and the i. p. administration of 0.025 mg/kg of cucurbitacins B and D attenuated both allodynia types. However, as cucurbitacin B showed a more toxic effect on non-cancerous (RAW 264.7) cells, further experiments were conducted with cucurbitacin D. The cucurbitacin D dose-dependently (0.025, 0.1, and 0.5 mg/kg) attenuated both allodynia types. In the spinal cord, paclitaxel injection increased the gene expression of noradrenergic (α 1-and α 2-adrenergic) receptors but not serotonergic (5-HT1A and 3) receptors. Cucurbitacin D treatment significantly decreased the spinal α 1- but not α 2-adrenergic receptors, and the amount of spinal noradrenaline was also downregulated. However, the tyrosine hydroxylase expression measured via liquid chromatography in the locus coeruleus did not decrease significantly. Finally, cucurbitacin D treatment did not lower the anticancer effect of chemotherapeutic drugs when co-administered with paclitaxel in CT-26 cell-implanted mice. Altogether, these results suggest that cucurbitacin D could be considered a treatment option against paclitaxel-induced neuropathic pain.

Stiff neural ordinary differential equations.

Neural Ordinary Differential Equations (ODEs) are a promising approach to learn dynamical models from time-series data in science and engineering applications. This work aims at learning neural ODEs for stiff systems, which are usually raised from chemical kinetic modeling in chemical and biological systems. We first show the challenges of learning neural ODEs in the classical stiff ODE systems of Robertson's problem and propose techniques to mitigate the challenges associated with scale separations in stiff systems. We then present successful demonstrations in stiff systems of Robertson's problem and an air pollution problem. The demonstrations show that the usage of deep networks with rectified activations, proper scaling of the network outputs as well as loss functions, and stabilized gradient calculations are the key techniques enabling the learning of stiff neural ODEs. The success of learning stiff neural ODEs opens up possibilities of using neural ODEs in applications with widely varying time-scales, such as chemical dynamics in energy conversion, environmental engineering, and life sciences.

Implantable powder-carrying microneedles for transdermal delivery of high-dose insulin with enhanced activity.

Recently, numerous transdermal drug delivery systems have been developed for safe and efficient delivery of biopharmaceuticals. Dissolving microneedles (DMNs) are one such drug delivery system, which have been developed to treat a variety of diseases in a minimally invasive manner. However, current DMN fabrication methods involve a reconstitution process of the therapeutics, which can result in degradation of the therapeutics or limited loading capacity for a reasonable application size. In the present study, we developed self-administrative powder-carrying microneedles (PCMs), lacking a reconstitution step, which implant insulin powder directly inside the skin without using a sticky patch. Compared with DMNs in the same geometries, the PCMs delivered the required dose in a more condensed form without considering insulin solubility and degradation during the fabrication process. Moreover, PCMs showed enhanced long-term stability and prolonged release kinetics, which could be utilized to treat diabetes without apparent safety issues. This implantable PCM technique will greatly impact the future of transdermal drug delivery systems because it is applicable to any type of therapeutic available in a dry powder formulation for a wide variety of biomedical applications.

Transdermal finasteride delivery via powder-carrying microneedles with a diffusion enhancer to treat androgenetic alopecia.

Androgenetic alopecia is a common form of scalp hair loss that affects men in their mid-twenties and increases with age. Finasteride (FNS) has been approved and used orally to treat androgenetic alopecia; however, systemic effects on other androgen-dependent tissues cause severe side-effects. To overcome these systemic effects and target hair follicles in the scalp only, numerous topical formulations of FNS have been developed and further combined with the solid microneedle (SMN) technique to create micro-channels in the skin, thus overcoming the skin barrier properties. However, low delivery efficiency and concerns over patient safety of SMNs remain major limitations of the treatment. In the present study, we developed a novel FNS delivery system comprising powder-carrying microneedles (PCMs), which is a patch-less and self-administered powder delivery technique that simultaneously overcomes the safety issues. This system could directly implant FNS inside the skin by encapsulating the FNS powder in the center of the PCMs. In addition, we introduced the concept of a diffusion enhancer for this system, which facilitated the dissolution and release of the implanted FNS powder to achieve its successful intradermal delivery. Using implanted FNS powder as a reservoir inside the skin, this novel system permitted sustained release of the implanted FNS powder for 3 days with only one application of FNS-PCMs. In addition, compared with the topical FNS-gel, the developed system showed a higher efficacy in promoting hair growth and increased the amount and density of hair while addressing the safety concerns. This approach has the potential to advance the field of transdermal drug delivery for any type of powdered drug in a wide variety of biomedical applications.

Tissue Interlocking Dissolving Microneedles for Accurate and Efficient Transdermal Delivery of Biomolecules.

The interest in safe and efficient transdermal drug delivery systems has been increasing in recent decades. In light of that, polymeric dissolving microneedles (DMNs) were developed as an ideal platform capable of delivering micro- and macro-biomolecules across the skin in a minimally invasive manner. A vast majority of studies, however, suggest that the shape of DMNs, as well as the elastic properties of skin, affects the delivery efficiency of materials encapsulated within DMNs. Likewise, in dynamic tissues, DMNs would easily distend from the skin, leading to inefficient delivery of encapsulated agents. Thus, herein, to improve delivery efficiency of DMN encapsulated agents, a novel hyaluronic acid backbone-based tissue interlocking DMN (TI-DMN) is developed. TI-DMN is simple to fabricate and significantly improves the transdermal delivery efficiency of encapsulated materials compared with traditional DMNs. The enhanced tissue interlocking feature of TI-DMN is achieved through its sharp tip, wide body, and narrow neck geometry. This paper demonstrates that TI-DMN would serve as an attractive transdermal delivery platform to enhance penetration and delivery efficiency of a wide range of biomolecules into the body.

Two-phase delivery using a horse oil and adenosine-loaded dissolving microneedle patch for skin barrier restoration, moisturization, and wrinkle improvement.

BACKGROUND: Dissolving microneedles (DMNs) have been used for skin restoration and wrinkle improvement. Although lipophilic compounds, for example, natural oils or ceramides, enrich the skin barrier, their delivery via DMNs is challenging because of DMN fabrication difficulties. OBJECTIVES: In the present study, we combined a topical formulation and a DMN patch to perform two-phase delivery comprising a lipophilic formulation and hydrophilic compound-loaded DMNs to improve skin barrier status and the efficacy of drug delivery. METHODS: Horse oil-spread and adenosine-loaded DMN arrays were developed in a single patch (HOS-Ad-DMN patch). In vitro analysis was conducted to confirm the successful delivery of the compositions. Clinical assessments were conducted on the lateral canthus of 20 women to compare the efficacy of HOS-Ad-DMN patches with that of adenosine-loaded DMN patches (Ad-DMN patches). RESULTS: Adenosine was delivered via the DMNs after skin penetration and horse oil was delivered successfully into the skin through the microchannels created by the Ad-DMNs. Compared with Ad-DMN patches, HOS-Ad-DMN patches significantly improved skin elasticity, hydration, dermal density, and wrinkles. No adverse events were observed. CONCLUSION: HOS-Ad-DMN patches are a safe and efficient system for skin restoration and wrinkle improvement.

Combinatorial application of dissolving microneedle patch and cream for improvement of skin wrinkles, dermal density, elasticity, and hydration.

BACKGROUND: Dissolving microneedles (DMNs), microscale needles with a biodegradable polymer matrix, have been widely investigated for transdermal drug delivery. However, the restricted drug loading space of DMNs limited the delivery of the desired quantity of active compounds. In this study, we developed novel combinatorial therapies involving sequential application of adenosine-loaded DMN (Ad-DMN) patches and a topical adenosine-loaded cream (Ad-cream). The application of DMNs created skin channels, which delivered encapsulated drugs from both the DMNs and cream. The use of combinatorial therapies can maximize drug delivery. METHODS: To compare the efficacy of combinatorial therapies and Ad-cream application, a double-blind clinical test was conducted over 10 weeks on 21 females with wrinkles around their eyes, and the skin parameters such as wrinkles, dermal density, elasticity, and hydration were analyzed. The skin irritation test was assessed by expert interviewers to elucidate undesirable side effects. RESULTS: The combinatorial therapies showed statistically significant efficacy for the improvement of average depth of wrinkles, dermal density, elasticity, and hydration after an 8-week application (P < 0.001). Adverse effects on the skin were not observed in any subject during the test period. CONCLUSION: The efficacy and safety results showed that the combinatorial therapies were a safe and outstanding innovation for the optimization of transdermal therapy.

Comparative Study of Two Droplet-Based Dissolving Microneedle Fabrication Methods for Skin Vaccination.

Dissolving microneedles (DMNs) have been widely studied in medical applications due to their pain-free administration, superior efficiency, and safe drug delivery. In skin vaccination, preserving the activity of the encapsulated antigen is an important consideration, as antigen activity is lost during DMN fabrication because of various stress factors. These stress factors vary between fabrication methods and each method affects the antigen's activity to different degrees. In this study, the activity of encapsulated antigens delivered by DMNs is compared between two recently developed DMN fabrication methods; droplet-born air blowing (DAB) and centrifugal lithography (CL) for a model scrub typhus vaccine antigen, ScaA. Although the in vitro analysis of ScaA-loaded DMNs (ScaA-DMNs) does not show any differences in physical properties depending on the fabrication methods, the immunogenicity of the CL-produced ScaA-DMN is significantly higher based on cytokine measurement and humoral immunity. DAB and CL differ in their solidification conditions, suggesting that solidification factors critically affect the encapsulated antigen's activity. ScaA-DMNs may also be stably stored for 4 weeks at room temperature. In conclusion, CL is a superior DMN fabrication method compared with DAB, and this study proves that DMN is feasible and practical for skin vaccination.

Transcutaneous implantation of valproic acid-encapsulated dissolving microneedles induces hair regrowth.

The interest in alternative material systems and delivery methods for treatment of androgenetic alopecia has been increasing in the recent decades. Topical application of valproic acid (VPA), an FDA-approved anticonvulsant drug, has been shown to effectively stimulate hair follicle (HF) regrowth by upregulating Wnt/ß-catenin, a key pathway involved in initiation of HF development. Moreover, a majority of studies have suggested that cutaneous wound re-epithelialization is capable of inducing HF through Wnt/ß-catenin pathway. Here, we report fabrication and evaluation of a novel VPA-encapsulating dissolving microneedle (DMN-VPA) that creates minimally invasive dermal micro-wounds upon application, significantly improving the VPA delivery efficiency. DMN-VPA not only delivers encapsulated VPA with higher accuracy than topical application, it also stimulates wound re-epithelialization signals involved in HF regrowth. Through a series of in vivo studies, we show that micro-wounding-mediated implantation of DMN-VPA upregulates expression of Wnt/ß-catenin pathway, alkaline phosphatase, proliferating cell nuclear antigen, loricrin and HF stem cell markers, including keratin 15, and CD34 more effectively than topical application.

Effects of two droplet-based dissolving microneedle manufacturing methods on the activity of encapsulated epidermal growth factor and ascorbic acid.

Dissolving microneedle (DMN) is an attractive, minimally invasive transdermal drug delivery technology. The drugs encapsulated in the DMNs are exposed to a series of thermal, chemical, and physical stresses during the fabrication process, decreasing their therapeutic activity. Current DMN fabrication methods, such as micro-molding, drawing lithography, droplet-born air blowing, and centrifugal lithography, undergo different manufacturing processes involving differing stress conditions. Among the methods, we compared the effects of two droplet-based methods, droplet-born air blowing and centrifugal lithography, on the activity of encapsulated drugs using epidermal growth factor and ascorbic acid as model drugs. Although the appearance and physical properties of DMNs fabricated by the two methods were similar, the immunoreactivity of encapsulated epidermal growth factor in centrifugal lithography and droplet-born air blowing was 92.08±2.86% and 80.67±8.00%, respectively, at baseline, and decreased to 75.32±19.40% and 41.75±16.17%, respectively, 24h after drug-loading. The free-radical scavenging activity of ascorbic acid was maintained at 88.24±0.78% in DMNs fabricated by centrifugal lithography, but decreased over time to 67.02±1.11% in DMNs fabricated by droplet-born air blowing. These findings indicate that the manufacturing conditions of centrifugal lithography exert less stress on the drug-loaded DMNs, minimizing activity loss over time, and therefore that centrifugal lithography is suitable for fabricating DMNs loaded with fragile biological drugs.

Physicochemical study of ascorbic acid 2-glucoside loaded hyaluronic acid dissolving microneedles irradiated by electron beam and gamma ray.

A dissolving microneedle (DMN) patch encapsulated with ascorbic acid 2-glucoside (AA2G) in a needle-shaped hyaluronic acid (HA) backbone was fabricated and sterilized by electron beam (e-beam, 5-40kGy) and gamma ray (γ-ray, 5-30kGy). DMN structures maintained their morphologies and fracture force regardless of e-beam and γ-ray irradiation doses. Both e-beam (40kGy) and γ-ray (20 and 30kGy) met the product sterility requirements for cosmetics and vaccines; however, γ-ray irradiation significantly degraded the encapsulated AA2G, while e-beam maintained AA2G activity. Thus, an e-beam dose of 40kGy, which satisfied the sterility requirements without loss of AA2G, is suitable for terminal sterilization of DMNs. Moreover, we confirmed that the optimized irradiation (e-beam, 40kGy) did not affect dissolution rate and drug release profile of DMNs. Further, we confirmed that HA, the backbone polymer of DMNs, could be utilized as a stabilizer that inhibits degradation of encapsulated AA2G by irradiation. This detailed analysis can be developed further to optimize various biological drugs in transdermal drug delivery systems.

Centrifugal Lithography: Self-Shaping of Polymer Microstructures Encapsulating Biopharmaceutics by Centrifuging Polymer Drops.

Polymeric microstructures encapsulating biopharmaceutics must be fabricated in a controlled environment to preserve the biological activity. There is increasing demand for simple methods designed to preserve the biological activity by utilizing the natural properties of polymers. Here, the paper shows that centrifugal lithography (CL) can be used for the fabrication of such microstructures in a single centrifugation, by engineering the self-shaping properties of hyaluronic acid (HA). In this method, HA drops are self-shaped into hourglass-microstructures to produce two dissolving microneedles (DMN), which facilitate transdermal delivery via implantation on the skin. In addition, tuberculin purified protein derivatives are encapsulated into HA DMNs under refrigerated conditions (4 °C) during CL. Therefore, the tuberculin skin test (TST) with the DMNs indicates minimal damage, as opposed to the case of TST with traditional hypodermic needles. These findings on the fabrication of polymeric microstructures with biopharmaceutics may trigger the development of various biomedical devices and therapies.

Enhanced Transdermal Delivery by Combined Application of Dissolving Microneedle Patch on Serum-Treated Skin.

Dissolving microneedle (DMN), a transdermal drug delivery system in which drugs are encapsulated in a biodegradable polymeric microstructure, is designed to dissolve after skin penetration and release the encapsulated drugs into the body. However, because of limited loading capacity of drugs within microsized structures, only a small dosage can be delivered, which is often insufficient for patients. We propose a novel DMN application that combines topical and DMN application simultaneously to improve skin permeation efficiency. Drugs in pretreated topical formulation and encapsulated drugs in DMN patch are delivered into the skin through microchannels created by DMN application, thus greatly increasing the delivered dose. We used 4-n-butylresorcinol to treat human hyperpigmentation and found that sequential application of serum formulation and DMNs was successful. In skin distribution experiments using Alexa Fluor 488 and 568 dyes as model drugs, we confirmed that the pretreated serum formulation was delivered into the skin through microchannels created by the DMNs. In vitro skin permeation and retention experiments confirmed that this novel combined application delivered more 4-n-butylresorcinol into the skin than traditional DMN-only and serum-only applications. Moreover, this combined application showed a higher efficacy in reducing patients' melanin index and hyperpigmented regions compared with the serum-only application. As combined application of DMNs on serum-treated skin can overcome both dose limitations and safety concerns, this novel approach can advance developments in transdermal drug delivery.

Anti-obesity effect of a novel caffeine-loaded dissolving microneedle patch in high-fat diet-induced obese C57BL/6J mice.

Natural products such as caffeine have been found to be effective in reducing body weight through lipolysis. Here, we report the successful loading of caffeine onto dissolving microneedle following inhibition of its crystal growth by hyaluronic acid (HA), the matrix material of the dissolving microneedle (DMN). Further, the anti-obesity activity of caffeine was evaluated in high-fat diet-induced obese C57BL/6J mice. After 6weeks of caffeine loaded dissolving microneedle patch (CMP) administration, lipolysis improved significantly as shown by leptin and adiponectin activity, which resulted in considerable weight loss of about 12.8±0.75% in high-fat diet-induced obese mice. Comparison of the levels of triglyceride, total cholesterol, high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol after CMP administration with the initial levels in obese mice indicated significant anti-obesity activity of CMP. These findings suggested that a novel CMP with an increased amount of caffeine loaded onto DMN has therapeutic activity against obesity.