Rapidly Dissolvable Microneedle Patches for Transdermal Delivery of Exenatide

Fabrication and Characterization of Thiolated Chitosan Microneedle Patch for Transdermal Delivery of Tacrolimus

Microneedle patch is a prominent strategy with minimal invasion and painless application to improve skin penetration of drug molecules. Herein, we report microneedle patch (MNP) as an alternative to the oral route for the systemic delivery of tacrolimus (TM), an immunosuppressant drug. Thiolated chitosan (TCS) based microneedle patch was fabricated and characterized in vitro and in vivo for its mechanical strength, skin penetration, drug release, and skin irritation. The MNP having 225 needles with 575 μm showed good mechanical properties in terms of tensile strength and percentage elongation. The skin penetration showed 84% penetration with no breakage. Histology of the mice skin after insertion showed the penetration of needles into the dermis. In vitro release and ex vivo permeation studies through Franz diffusion cell showed the sustained release (82.5%) of TM from the MNP with significantly higher (p < 0.05) skin permeation as compared with controls, respectively. Moreover, in vivo biocompatibility in rats showed the safety of the material and patch. Thus, the TCS microneedle patch has the potential to be developed as a transdermal delivery system for tacrolimus with improved bioavailability and sustained release over a longer period.

Transdermal delivery of rapamycin with poor water-solubility by dissolving polymeric microneedles for anti-angiogenesis

Angiogenesis plays an important role in the occurrence and development of skin tumors and vascular anomalies (VAs). Many drugs have been adopted for the inhibition of angiogenesis, among which rapamycin (RAPA) possesses good application prospects. However, the clinical potential of RAPA for VAs is limited by its poor solubility, low bioavailability, and high cytotoxicity. To extend its application prospect for VAs treatment, in this study, we develop RAPA-loaded dissolving polymeric microneedles (RAPA DMNs) made of polyvinylpyrrolidone (PVP) due to its excellent solubilizing ability. RAPA DMNs are shown to have sufficient mechanical strength to overcome the skin barrier of the stratum corneum and could deliver RAPA to a depth of 200 μm. The microneedle shafts completely dissolve and 80% of the drug could be released within 10 min after insertion ex vivo. The DMNs-penetrated mice skin could repair itself within 4 h after the application of RAPA DMNs. RAPA DMNs also show good anti-angiogenic effect by inhibiting the growth of human umbilical vein endothelial cells (HUVECs) and decreasing the secretion of vascular endothelial growth factor (VEGF). Therefore, RAPA DMNs promisingly provide a safe and efficient approach for VAs treatment.

A fast-dissolving microneedle array loaded with chitosan nanoparticles to evoke systemic immune responses in mice

Microneedle (MN) arrays offer an alternative approach to hypodermic injection via syringe needles. In this work, polyvinylpyrrolidone (PVP)-based fast dissolving MN arrays were developed in which the needle tips were loaded with chitosan nanoparticles (NPs) for coencapsulation of a model antigen, ovalbumin (OVA), and an adjuvant, CpG oligodeoxynucleotides (CpG). After insertion into the skin, these MN arrays fully dissolved within 3 min to release antigen and adjuvant co-loaded NPs rapidly in the epidermal layer. Positively charged chitosan was proven to be an excellent carrier for negatively charged OVA and CpG, which formed nanocomplexes via simple electrostatic interactions and greatly enhanced the uptake efficiency of OVA in DC2.4 dendritic cells. Vaccination studies in mice further demonstrated that chitosan NPs effectively accumulated in peripheral lymph nodes, thus inducing greatly enhanced immune responses compared to those of free OVA. The antibody dose-response curve further demonstrated that MN immunization achieved comparable levels of immune responses as compared to conventional subcutaneous injections in a more convenient and less invasive way. Overall, a PVP-based fast dissolving MN array with chitosan NPs represents a promising and robust platform system for efficient transcutaneous vaccine delivery.

Hyaluronic Acid-Based Dissolving Microneedle Patch Loaded with Methotrexate for Improved Treatment of Psoriasis

Methotrexate (MTX) is one of the first-line treatments for moderate to severe psoriasis, while the side effects caused by injection and oral administration of MTX greatly restrict its clinical application. Transdermal drug delivery offers a desirable alternative to the conventional approaches, but the performances of the currently available skin penetration enhancement techniques are not so satisfactory. To address these limitations, we developed a dissolving microneedle (MN) patch made of hyaluronic acid (HA) with excellent water solubility, biocompatibility, biodegradability, and mechanical properties. The amount of MTX encapsulated in the needles of the patch could be controlled during the fabrication process for precise dosage. Interestingly, the MTX-loaded MNs successfully penetrated imiquimod (IMQ)-induced thickened epidermis in mice and delivered the drug intralesionally. Meanwhile, fast dissolution of HA endowed the MNs with operability for patients. We found that the MTX-loaded MNs not only showed well-maintained inhibitory effect in vitro but also alleviated the psoriasis-like skin inflammation in mice. Moreover, the MTX-loaded MNs were significantly more efficacious than taking the same dose of drug orally. Consequently, a higher oral dose of MTX was required for a comparable amelioration, which in turn increased its systemic toxicity. Taken together, the proposed MTX-loaded dissolving MN patch strategy provides a new opportunity for efficient and safe treatment of psoriasis.

Dissolving Triamcinolone-Embedded Microneedles for the Treatment of Keloids: A Single-Blinded Intra-Individual Controlled Clinical Trial

INTRODUCTION

Keloids are a prevalent chronic skin disorder with significant psychosocial morbidity. Intralesional corticosteroid injections are the first-line treatment but are painful and require repeated injections by medical professionals. Dissolving microneedles are a novel method of cutaneous drug delivery that induces minimal/no pain and can be self-administered. The objective of the study was to evaluate the efficacy and safety of triamcinolone-embedded dissolving microneedles in treatment of keloids.

METHODS

This was a single-blind, intra-individual controlled two-phase clinical trial of 8-week duration each. Two keloids per subject were selected for (1) once-daily 2-min application with microneedles for 4 weeks, followed by no treatment for the next 4 weeks, or (2) non-intervention as control. Primary outcome was change in keloid volume as assessed by a high-resolution 3D scanner.

RESULTS

There was significant reduction in keloid volume compared with controls after 4 weeks of treatment. This reduction was greater with a higher dosage of triamcinolone used.

CONCLUSIONS

Once-daily application of dissolving triamcinolone-embedded microneedles significantly reduced the volume of keloids. The treatment was safe, can be self-administered and can serve as an alternative for patients unsuitable for conventional treatments.

TRIAL REGISTRATION

Trial Registry: Health Science Authority (Singapore) Clinical Trials Register Registration number: 2015/00440.

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.

Enhanced in vitro efficacy for inhibiting hypertrophic scar by bleomycin-loaded dissolving hyaluronic acid microneedles

Hypertrophic scarring is a widespread skin disorder that affects a patient's confidence and quality of life.

Assessment of mechanical stability of rapidly separating microneedles for transdermal drug delivery

The rapidly separating microneedles (RS-PP-MNs), composed of PVA (separable arrow head) MNs and a poly(L-lactide-co-D, L-lactide) (PLA) supporting array, are used for transdermal delivery system at high humidity. The fabricated RS-PP-MNs should have sufficient mechanical strength at different humidity. In general, the water adsorption rate was increased with increasing humidity; by contrast, storage time was decreased with increasing humidity. The higher water adsorption rate indicated the lower mechanical strength, thereby lowering drug delivery efficiency. The prepared RS-PP-MNs could be successfully inserted within the skin at high humid atmosphere due to PLA supporting array. The bright field and fluorescence microscopic images suggested the probable real-time applicability of RS-PP-MNs. The in vitro and in vivo assay suggested that RS-PP-MNs potentially were able to deliver the drugs at high humidity condition. The significant improvement in the drug delivery efficiency and skin penetration ability was observed compared with the traditional MNs. In addition, the fabrication of RS-PP-MNs is facile and scalable. Therefore, the prepared RS-PP-MNs with supporting solid PLA array might be advantageous in real-time applications. This study is of great importance for the MN field as it offers more theoretical support for clinical applications.

Self-Dissolving Microneedle Arrays for Transdermal Absorption Enhancement of Human Parathyroid Hormone (1-34)

Human parathyroid hormone (1-34) (PTH) has been widely used as the subcutaneous injection formulation for the treatment of osteoporosis. In the present study, we developed an efficient transdermal delivery system of PTH by using dissolving microneedle arrays (MNs) composed of hyaluronic acid (HA) for the treatment of osteoporosis. PTH-loaded MNs, with needle length 800 µm, were fabricated via a micro-molding method. The stability of PTH in MNs was found to be 6-fold higher than that of PTH solution when stored at room temperature (15–20 °C) for one month. Micron-scale pores were clearly visible in rat skin following application of PTH-loaded MNs. PTH-loaded MNs were completely dissolved by 60 min following application to rat skin. The bioavailability (BA) of PTH relative to subcutaneous injection was 100 ± 4% following application of PTH-loaded MNs in rats. In addition, PTH-loaded MNs were found to effectively suppress decreases in bone density in a rat model of osteoporosis. Furthermore, no skin irritation was observed at the site of application in rats. These findings indicate that our dissolving MNs have a potential use in formulations for the transdermal delivery of PTH and for the treatment of osteoporosis.

Novel Whole-Cell Inactivated Neisseria Gonorrhoeae Microparticles as Vaccine Formulation in Microneedle-Based Transdermal Immunization

Neisseria gonorrhoeae is a strict human pathogen responsible for more than 100 million new sexually transmitted infections worldwide each year. Due to the global emergence of antibiotic resistance, the Center for Disease control (CDC) recently listed N. gonorrhoeae as an urgent threat to public health. No vaccine is available in spite of the huge disease burden and the possibility of untreatable gonorrhea. The aim of this study is to investigate the immunogenicity of a novel whole-cell-based inactivated gonococcal microparticle vaccine formulation loaded in dissolvable microneedles for transdermal administration. The nanotechnology-based vaccine formulation consists of inactivated whole-cell gonococci strain CDC-F62, spray dried and encapsulated into biodegradable cross-linked albumin matrix with sustained slow antigen release. The dry vaccine nanoparticles were then loaded in a dissolvable microneedle skin patch for transdermal delivery. The efficacy of the whole-cell microparticles vaccine formulation loaded in microneedles was assessed in vitro using dendritic cells and macrophages as well as in vivo mouse model. Antibody titers were measured using an enzyme immunosorbent assay (ELISA) and antigen-specific T lymphocytes were assessed in spleens and lymph nodes. Here we report that whole-cell-based gonococcal microparticle vaccine loaded in dissolvable microneedles for transdermal administration induced significant increase in antigen-specific IgG antibody titers and antigen-specific CD4 and CD8 T lymphocytes in mice compared to gonococcal antigens in solution or empty microneedles. Significant increase in antigen-specific IgG antibody levels was observed at the end of week 2 in groups that received the vaccine compared to the group receiving empty nanoparticles. The advantages of using formalin-fixed whole-cell gonococci that all immunogenic epitopes are covered and preserved from degradation. The spherical shaped micro and nanoparticles are biological mimics of gonococci, therefore present to the immune system as invaders but without the ability to suppress adaptive immunity. In conclusion, the transdermal delivery of microparticles vaccine via a microneedle patch was shown to be an effective system for vaccine delivery. The novel gonorrhea nanovaccine is cheap to produce in a stable dry powder and can be delivered in microneedle skin patch obviating the need for needle use or the cold chain.

Formulation, characterization and evaluation of mRNA-loaded dissolvable polymeric microneedles (RNApatch)

In this paper, we report a proof of concept study on the fabrication, characterization and therapeutic evaluation of in vitro transcribed messenger RNA (mRNA) loaded in a dissolving microneedle patch (RNApatch). We show that low molecular weight polyvinylpyrrolidone (PVP) can directly be used without further purification for RNApatch fabrication with no detectable mRNA degradation. Physical and functional integrity of mRNA stored within the RNApatch are completely preserved for at least 2 weeks under ambient conditions. While the loading of mRNA into RNApatch is limited by the solubility of mRNA in concentrated PVP solution, mechanical strength of RNApatch is not compromised by the presence of mRNA. RNApatch can mediate in vivo transgene expression of mRNA encoding luciferase for up to 72 hours and transfection efficiency and kinetics mediated by RNApatch compares favorably to subcutaneous injection. Interestingly, mRNA transfection efficiency does not correlate with contact surface area but instead increases with deeper delivery depths. In an E.G7-OVA immunotherapy model, RNApatch induces slightly higher cellular and humoral immune responses compared to subcutaneous injection. In conclusion, RNApatch is a viable delivery platform for mRNA and represents an attractive option with significant translation potential for the delivery of mRNA therapeutics.

Tip-loaded fast-dissolving microneedle patches for photodynamic therapy of subcutaneous tumor

5-Aminolevulinic acid (ALA) based photodynamic therapy (PDT) is a modality for the treatment of cancers. However, due to its hydrophilicity and zwitterionic nature, the transdermal delivery of ALA is limited for the PDT of subcutaneous tumor. To address this problem, tip-loaded fast-dissolving microneedles made of sodium hyaluronate (HA) were fabricated by two casting method. 122 μg of ALA was loaded per microneedle patch and mainly distributed in the tips, which could improve the utilization of drug and avoid the waste of drug residue in the base of microneedle patch after use. The HA microneedles could pierce stratum corneum with insertion depth about 200 μm in isolated skin. After insertion, HA microneedles were rapidly dissolved to release the encapsulated drug to improve patients' convenience and compliance. Importantly, in a subcutaneous mouse tumor model established in BALB/c nude mice, the PDT efficacy of ALA-loaded HA microneedle group was much better than ALA injection group in spite of a relatively lower ALA dose with HA microneedles. The tumor inhibition rate of ALA-loaded HA microneedle group (containing 0.61 mg of ALA) was up to 97%, while the tumor inhibition rate of ALA injection group (containing 1.65 mg of ALA) was just 66%. In addition, microchannels created by microneedle patch were quickly recovered within 3 h after insertion. Overall, the tip-loaded fast-dissolving HA microneedle patch with ALA as drug was promising and might improve topical PDT efficacy of subcutaneous tumor in an efficient and safe manner.

3D printed drug delivery and testing systems - a passing fad or the future?

The US Food and Drug Administration approval of the first 3D printed tablet in 2015 has ignited growing interest in 3D printing, or additive manufacturing (AM), for drug delivery and testing systems. Beyond just a novel method for rapid prototyping, AM provides key advantages over traditional manufacturing of drug delivery and testing systems. These includes the ability to fabricate complex geometries to achieve variable drug release kinetics; ease of personalising pharmacotherapy for patient and lowering the cost for fabricating personalised dosages. Furthermore, AM allows fabrication of complex and micron-sized tissue scaffolds and models for drug testing systems that closely resemble in vivo conditions. However, there are several limitations such as regulatory concerns that may impede the progression to market. Here, we provide an overview of the advantages of AM drug delivery and testing, as compared to traditional manufacturing techniques. Also, we discuss the key challenges and future directions for AM enabled pharmaceutical applications.

Zein Microneedles for Localized Delivery of Chemotherapeutic Agents to Treat Breast Cancer: Drug Loading, Release Behavior, and Skin Permeation Studies

Localized delivery of chemotherapeutic agents to treat breast cancer could limit their adverse drug reactions. The aim of this study was to investigate the influence of physico-chemical properties of chemotherapeutic agents in their loading, release behavior, and skin permeation using microneedles. Zein microneedles were fabricated using the micromolding technique containing 36 microneedles in a 1-cm² area. These microneedles were loaded with two anti-breast cancer drugs, tamoxifen and gemcitabine, having different water solubilities. Entrapment or surface coating of chemotherapeutic agents in zein microneedles was optimized to achieve greater loading efficiency. The greatest loading achieved was 607 ± 21 and 1459 ± 74 μg for tamoxifen and gemcitabine using the entrapment approach, respectively. Skin permeation studies in excised porcine skin showed that the coating on microneedles approach results in greater skin deposition for tamoxifen; while the poke-and-patch approach would provide greater skin permeation for gemcitabine. Taken together, it can be concluded that different loading strategies and skin penetration approaches have to be studied for delivery of small molecules using polymeric microneedles.

Exendin-4-encapsulated dissolving microneedle arrays for efficient treatment of type 2 diabetes

Dissolving microneedles (DMNs) are microscopic needles capable of delivering encapsulated compounds and releasing them into the skin in a minimally invasive manner. Most studies indicate that encapsulating therapeutics in DMNs is an efficacious approach; however, the importance of evaluating the activity of encapsulated compounds, during the fabrication process, has not been examined in detail. Conducting an analysis of thermal, chemical, and physical stress factors, including temperature, pH, and the interaction of the polymer and therapeutics mixture during preparation, is essential for retaining the activity of encapsulated therapeutics during and after fabrication. Here, we optimised the thermal, chemical, and physical parameters for the fabrication of exendin-4 (Ex-4)-encapsulated DMNs (Ex-4 DMNs). Ex-4, a peptide agonist of glucagon-like peptide (GLP) receptor, is used for glycaemic control in patients with type 2 diabetes. Our findings indicate that optimising the parameters involved in DMN fabrication retained the activity of Ex-4 by up to 98.3 ± 1.5%. Ex-4 DMNs reduced the blood-glucose level in diabetic mice with efficiency similar to that of a subcutaneous injection. We believe that this study paves way for the commercialisation of an efficient and minimally invasive treatment for patients with type 2 diabetes.

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.

Sustained-release study on Exenatide loaded into mesoporous silica nanoparticles: in vitro characterization and in vivo evaluation

BACKGROUND

Exenatide (EXT), the first glucagon-like peptide-1 receptor agonist, has been approved as an adjunctive therapy for patients with type 2 diabetes. Due to EXT's short half-life, EXT must be administrated by continuous subcutaneous (s.c.) injection twice daily. In previous studies, many studies on EXT loaded into polymer materials carriers for sustained release had been reported. However, these carriers have some defects, such as hydrophobicity, low surface energy, low mechanical strength, and poor chemical stability. Therefore, this study aims to develop a novel drug delivery system, which is EXT loaded into well-ordered hexagonal mesoporous silica structures (EXT-SBA-15), to control the sustainability of EXT.

METHODS

SBA-15 was prepared by hydrothermal method with uniform size. Morphology of SBA-15 was employed by transmission electron microscopy. The pore size of SBA-15 was characterized by N₂ adsorption-desorption isotherms. The in vitro drug release behavior and pharmacokinetics of EXT-SBA-15 were investigated. Furthermore, the blood glucose levels of diabetic mice were monitored after subcutaneous injection of EXT-Sol and EXT-SBA-15 to evaluate further the stable hypoglycemic effect of EXT-SBA-15.

RESULTS

EXT-SBA-15 showed a higher drug loading efficiency (15.2 ± 2.0%) and sustained-release features in vitro. In addition, pharmacokinetic studies revealed that the EXT-SBA-15 treatment group extended the half-life t _1/2(β) to 14.53 ± 0.70 h compared with that of the EXT solution (EXT-Sol) treatment group (0.60 ± 0.08 h) in vivo. Results of the pharmacodynamics study show that the EXT-SBA-15 treatment group had inhibited blood glucose levels below 20 mmol/L for 25 days, and the lowest blood glucose level was 13 mmol/L on the 10th day.

CONCLUSIONS

This study demonstrates that the EXT-SBA-15 delivery system can control the sustainability of EXT and contribute to improve EXT clinical use.

Fabrication of two-layer dissolving polyvinylpyrrolidone microneedles with different molecular weights for in vivo insulin transdermal delivery

Fabrication of two-layer dissolving polyvinylpyrrolidone microneedles for in vivo insulin transdermal delivery.

Microneedles with Controlled Bubble Sizes and Drug Distributions for Efficient Transdermal Drug Delivery

Drug loaded dissolving microneedles (DMNs) fabricated with water soluble polymers have received increasing attentions as a safe and efficient transdermal drug delivery system. Usually, to reach a high drug delivery efficiency, an ideal drug distribution is gathering more drugs in the tip or the top part of DMNs. In this work, we introduce an easy and new method to introduce a bubble with controlled size into the body of DMNs. The introduction of bubbles can prevent the drug diffusion into the whole body of the MNs. The heights of the bubbles are well controlled from 75 μm to 400 μm just by changing the mass concentrations of polymer casting solution from 30 wt% to 10 wt%. The drug-loaded bubble MNs show reliable mechanical properties and successful insertion into the skins. For the MNs prepared from 15 wt% PVA solution, bubble MNs achieve over 80% of drug delivery efficiency in 20 seconds, which is only 10% for the traditional solid MNs. Additionally, the bubble microstructures in the MNs are also demonstrated to be consistent and identical regardless the extension of MN arrays. These scalable bubble MNs may be a promising carrier for the transdermal delivery of various pharmaceuticals.

Current and emerging formulation strategies for the effective transdermal delivery of HIV inhibitors

Current and emerging formulation strategies for skin permeation are poised to open the transdermal drug delivery to a broader range of small molecule compounds that do not fit the traditional requirements for successful transdermal drug delivery, allowing the development of new patch technologies to deliver antiretroviral drugs that were previously incapable of being delivered through transdermal means. Transdermal drug delivery offers several distinct advantages over traditional dosage forms. Current antiretroviral drugs used for the treatment of HIV infection include a variety of highly active small molecule compounds with significantly limited skin permeability, and thus new and novel means of enhancing transport through the skin are needed. Current and emerging formulation strategies are poised to open the transdermal drug delivery to a broader range of compounds that do not fit the traditional requirements for successful transdermal drug delivery, allowing the development of new patch technologies to deliver antiretroviral drugs that were previously incapable of being delivered through transdermal means. Thus, with continuing research into skin permeability and patch formulation strategies, there is a large potential for antiretroviral transdermal drug delivery.

A patchless dissolving microneedle delivery system enabling rapid and efficient transdermal drug delivery

Dissolving microneedles (DMNs) are polymeric, microscopic needles that deliver encapsulated drugs in a minimally invasive manner. Currently, DMN arrays are superimposed onto patches that facilitate their insertion into skin. However, due to wide variations in skin elasticity and the amount of hair on the skin, the arrays fabricated on the patch are often not completely inserted and large amount of loaded materials are not delivered. Here, we report “Microlancer”, a novel micropillar based system by which patients can self-administer DMNs and which would also be capable of achieving 97 ± 2% delivery efficiency of the loaded drugs regardless of skin type or the amount of hair on the skin in less than a second.