Microneedle pretreatment improves efficacy of cutaneous topical anesthesia

Efficacy and Safety of Introduction Timolol Maleate by Manometer Microneedles among Infantile Hemangioma: A Retrospective Study in China

OBJECTIVE

 The objective of the study was to compare the effective rate, cure rate, adverse reaction rate, and effective time of three methods in the treatment of infantile hemangioma, hoping to provide reference for improving the clinical therapeutic effect.

METHODS

 This is a retrospective study of 307 infantile hemangioma patients admitted to the Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University, from January 2014 to October 2021. The patients were divided into three groups. In group A, timolol maleate solution was introduced by the nano-microneedle technique (97 cases); in group B, timolol maleate drops dipped in medical swabs were applied (107 cases); and group C patients took propranolol orally (103 cases). The effective rate, cure rate, adverse reaction rate, and effective time of treatment were recorded and compared.

RESULTS

 The total effective rate, total cure rate, and total adverse reaction rate of the three groups were 87.6, 65.2, and 9.4%, respectively. The results showed that the effective and cure rates of group A were higher than those of group B (92.8 and 76.3%, respectively; p < 0.05), the adverse reaction rate of group C was higher than that of group B (17.5%, p < 0.05), and the effective time of group A was shorter than that of groups B and C. In most patients, symptoms significantly improved within 2 months (p < 0.05).

CONCLUSION

 Timolol maleate introduced by nanometer microneedles is an effective and safe treatment for superficial hemangioma in infants with the highest effective and cure rates, lower incidence of adverse reactions, and the shortest effective treatment time.

Clinical efficacy and safety of nano-microneedle-assisted phenylethyl resorcinol for the treatment of infraorbital dark circles

BACKGROUND

Infraorbital dark circles (DC) are defined as a symptom that presents darkness under infraorbital eyelids. The objective of this study was to evaluate the efficacy and safety of nano-microneedle-assisted phenylethyl resorcinol (PR) for the treatment of infraorbital dark circles.

METHODS

Twenty female participants were randomized to two groups. In the experimental group (group E), participants received topical PR gel under the left orbit once a day and topical plus nano-microneedle-assisted PR gel under the right orbit twice a week. In the control group (group C), participants were treated with gel without PR. Melanin index (MI) and erythema index (EI) were measured before the session (T0), 4 and 8 weeks during the treatment session (T4, T8), and 1 and 2 months after the last session (T12, T16). The global assessment was performed by a blinded dermatologist.

RESULTS

The mean value of MI in group E was significantly lower than the baseline at T8 (P < .05), and the right side decreased more significantly than the left side (P < .05). However, there was no difference of MI before and after treatment in group C (P > .05). There was no big difference of the mean EI between the two sides (P > .05). The treatment was well tolerated, and no serious adverse effects were reported.

CONCLUSION

PR combined with nano-microneedle could be an effective and safe method for infraorbital DC.

Evaluation of the clinical impact of repeat application of hydrogel-forming microneedle array patches

Hydrogel-forming microneedle array patches (MAPs) have been proposed as viable clinical tools for patient monitoring purposes, providing an alternative to traditional methods of sample acquisition, such as venepuncture and intradermal sampling. They are also undergoing investigation in the management of non-melanoma skin cancers. In contrast to drug or vaccine delivery, when only a small number of MAP applications would be required, hydrogel MAPs utilised for sampling purposes or for tumour eradication would necessitate regular, repeat applications. Therefore, the current study was designed to address one of the key translational aspects of MAP development, namely patient safety. We demonstrate, for the first time in human volunteers, that repeat MAP application and wear does not lead to prolonged skin reactions or prolonged disruption of skin barrier function. Importantly, concentrations of specific systemic biomarkers of inflammation (C-reactive protein (CRP); tumour necrosis factor-α (TNF-α)); infection (interleukin-1β (IL-1β); allergy (immunoglobulin E (IgE)) and immunity (immunoglobulin G (IgG)) were all recorded over the course of this fixed study period. No biomarker concentrations above the normal, documented adult ranges were recorded over the course of the study, indicating that no systemic reactions had been initiated in volunteers. Building upon the results of this study, which serve to highlight the safety of our hydrogel MAP, we are actively working towards CE marking of our MAP technology as a medical device.

Dissolving Microneedles for Rapid and Painless Local Anesthesia

Microneedles are emerging drug delivery methods for painless treatment. The current study tested dissolving microneedles containing lidocaine (Li-DMN) for use in local anesthesia. An Li-DMN patch was fabricated by centrifugal lithography with carboxymethyl cellulose as a structural polymer and assessed for physical properties by optical microscopy and a fracture force analyzer. The biocompatibility was evaluated by a histology section in vitro and by ear thickness in vivo. The efficacy of the Li-DMN patch was assessed by electrophysiological recordings in primary cultured sensory neurons in vitro and a von Frey test on rats’ hind paws in vivo. The physical properties of the microneedle showed enough rigidity for transdermal penetration. The maximal capacity of lidocaine-HCl in the Li-DMN patch was 331.20 ± 6.30 µg. The cytotoxicity of the dissolving microneedle to neuronal cells was negligible under an effective dose of lidocaine for 18 h. Electrophysiological recordings verified the inhibitory effect of the voltage-gated sodium channel current by the Li-DMN patch in vitro. A skin reaction to the edema test and histologic analysis of the rats’ ears after application of the Li-DMN patch were negligible. Also, the application of the Li-DMN patch reduced the nocifensive behavior of the rats almost immediately. In conclusion, the dissolving microneedle patch with carboxymethyl cellulose is a promising candidate method for the painless delivery of lidocaine-HCl.

Microneedles combined with a sticky and heatable hydrogel for local painless anesthesia

In view of the inherent defects of traditional syringe anesthesia (pain, inaccurate anesthesia area, swelling after injection, slow recovery etc.), this article proposed a new anesthesia system based on microneedles and a hydrogel. After loading with AuNPs, a sticky PDA-PAM-AuNP hydrogel with near-infrared (NIR) light response properties was prepared here. After using microneedles (to open the skin of the target anesthesia area), a hydrogel patch embedded with a medical anesthetic soaked sponge was pasted to realize local painless anesthesia. The effects of anesthesia can also be modulated by external NIR. Compared to traditional syringe anesthesia, this hydrogel + microneedle method resulted in reduced pain, higher anesthetic accuracy and faster recovery, making it a promising local anesthesia alternative in clinical applications.

Microneedle System for Transdermal Drug and Vaccine Delivery: Devices, Safety, and Prospects

Microneedle (MN) delivery system has been greatly developed to deliver drugs into the skin painlessly, noninvasively, and safety. In the past several decades, various types of MNs have been developed by the newer producing techniques. Briefly, as for the morphologically, MNs can be classified into solid, coated, dissolved, and hollow MN, based on the transdermal drug delivery methods of "poke and patch," "coat and poke," "poke and release," and "poke and flow," respectively. Microneedles also have other characteristics based on the materials and structures. In addition, various manufacturing techniques have been well-developed based on the materials. In this review, the materials, structures, morphologies, and fabricating methods of MNs are summarized. A separate part of the review is used to illustrate the application of MNs to deliver vaccine, insulin, lidocaine, aspirin, and other drugs. Finally, the review ends up with a perspective on the challenges in research and development of MNs, envisioning the future development of MNs as the next generation of drug delivery system.

Transdermal sampling of vitamin D3 and 25-hydroxyvitamin D3

AIM

Transdermal analysis is proposed for vitamin D₃ and its hydroxylated metabolite to overcome problems associated with blood analysis.

METHODS

Vitamin D₃ was extracted directly from skin with solid patches and liquid phases. Deuterium-labeled vitamin D₃ was added to the extraction solutions to compensate for variability and accurately determine the rate of transdermal transfer. Of the different extraction solvents tested, 50:50 octanol:isopropanol showed the best results, with an accuracy of 115% and reproducibility better than 30%.

CONCLUSION

The research shows that transdermal route can be used for analysis of vitamin D₃ in porcine skin. When microneedles are used, accurate measurements were obtained in 1 h. With intact skin, the highest accuracy was obtained when extraction was done for 2 h.

Therapeutic applications and pharmacoeconomics of microneedle technology

INTRODUCTION

Microneedle (MN) arrays contain a backing plate with multiple microscopic projections to puncture the skin and can be used to deliver drug in a minimally invasive way. Advantages of MNs are numerous including administration of large molecules, avoiding first-pass metabolism, ease of administration, lack of pain, site-specific drug targeting, and dose reduction due to increased absorption efficacy. The growth in the transdermal market has been fueled by an increasing number of chronic disease patients and a demand for easy and pain-free drug administration.

AREAS COVERED

This paper highlights the use of MNs as a drug delivery system and discusses their potential market impact from a cost perspective. A number of clinical trials have been conducted and are listed to illustrate the potential applications of MNs for therapeutic use. Furthermore, the cosmetic market has made use of the MN technology, indicating that MNs can be used safely, efficaciously, and on a commercial scale. Furthermore, the cost-effectiveness of MNs is discussed.

EXPERT COMMENTARY

For MNs to become commercially available for therapeutic use, a number of factors will need to be considered: safety, ease of use, manufacturing and storage, uptake, effectiveness, and regulatory requirements.

Human studies with microneedles for evaluation of their efficacy and safety

INTRODUCTION

During the past two decades, many studies have documented the development of microneedles (MNs) as a feasible technique for the effective administration of drugs. More and more human studies have been done with MNs to bridge the gap between research and market applications that provide efficacious techniques for clinical implementation.

AREAS COVERED

The aim of this review is provide a brief description of the status of human study with MNs and to demonstrate progress for the right use of microneedle arrays in clinical settings. It also describes the considerations for clinical application with each type of MNs.

EXPERT OPINION

Microneedle systems were introduced to overcome the limitations of conventional methods of drug administration. Lots of microneedle systems have undergone clinical evaluation to determine their efficacy and safety, and many studies have demonstrated positive results. The successful clinical use of the microneedle in vaccine therapy is remarkable and supports the importance of conducting further tests in a wide range of medical applications. Self-administered MNs appeared to be an attractive alternative method that needs further research to become a reality in the near future.

Efficacy of functional microarray of microneedles combined with topical tranexamic acid for melasma: A randomized, self-controlled, split-face study

To evaluate the efficacy of a functional microarray of microneedles (MNs) plus topical tranexamic acid (TA) for melasma in middle-aged women in China.Thirty female subjects with melasma were enrolled in this study. The left or right side of the face was chosen randomly to be pretreated with a functional microarray of MNs, followed by topical 0.5% TA solution once per week for 12 weeks. The other half-face was the control, treated with a sham device plus topical 0.5% TA solution. At baseline and at weeks 4, 8, and 12 of treatment, clinical (photographic) evaluations and parameters determined by Visia were recorded. At baseline and week 12, patient satisfaction scores and the biophysical parameters measured by Mexameter were also recorded. Side effects were evaluated at baseline and at the end of the 12 weeks.In total, 28 women (93.3%) completed the study. The brown spots' scores measured by Visia were significantly lower on the combined therapy side than on the control side at 12 weeks after starting treatment; there was no significant difference between sides at 4 or 8 weeks. After 12 weeks, melanin index (MI) decreased significantly in both 2 groups, and the MI was significantly less on the combined side at week 12. Transepidermal water loss, roughness, skin hydration, skin elasticity, and erythema index showed no significant differences between 2 sides at baseline, 4, 8, and 12 weeks after treatment. Physicians' evaluations of photographs showed better results at week 12 with combined therapy: >25% improvement was observed in the MNs plus TA side in 25 patients, and in the TA side in only 10 patients. Subjective satisfaction scores on both sides increased significantly. The participants were more satisfied with the results of the combined therapy side than the control side. No obvious adverse reactions were observed throughout the study.Combined therapy with a functional microarray of MNs and topical TA solution is a promising treatment for melasma.

Microfabrication for Drug Delivery

This review is devoted to discussing the application of microfabrication technologies to target challenges encountered in life processes by the development of drug delivery systems. Recently, microfabrication has been largely applied to solve health and pharmaceutical science issues. In particular, fabrication methods along with compatible materials have been successfully designed to produce multifunctional, highly effective drug delivery systems. Microfabrication offers unique tools that can tackle problems in this field, such as ease of mass production with high quality control and low cost, complexity of architecture design and a broad range of materials. Presented is an overview of silicon- and polymer-based fabrication methods that are key in the production of microfabricated drug delivery systems. Moreover, the efforts focused on studying the biocompatibility of materials used in microfabrication are analyzed. Finally, this review discusses representative ways microfabrication has been employed to develop systems delivering drugs through the transdermal and oral route, and to improve drug eluting implants. Additionally, microfabricated vaccine delivery systems are presented due to the great impact they can have in obtaining a cold chain-free vaccine, with long-term stability. Microfabrication will continue to offer new, alternative solutions for the development of smart, advanced drug delivery systems.

Oral dyclonine hydrochloride mucilage versus tetracaine spray in electronic flexible laryngoscopy: A prospective, randomized controlled trial

BACKGROUND

Topical anesthesia is important for electronic flexible laryngoscopy (EFL) utilization. We hypothesized that oral dyclonine hydrochloride mucilage (ODHM) is superior to tetracaine spray (TS) in patients undergoing EFL examination.

METHODS

This study included 932 patients randomized into either an ODHM or TS group, in which patients received either a single utilization of ODHM or TS administered via spray in three intervals. A 4.9 mm diameter flexible PENTAX-VNL-1570STK insertion tube placed into a Naso-Pharyngo-Laryngoscope (PENTAX Medical, Japan) was used in the procedure. Visual analogue scale (VAS) (0-10) was used to evaluate patient tolerance and procedure success by the operator, independently. Procedure time was also recorded.

RESULTS

Both patients' and doctors' VAS scores were significantly higher in the ODHM group compared to the TS group. When subgroup analysis was made according to the procedure length (100 s), there was no significant difference in VAS between ODHM and TS groups in the short time procedure (≤100 s), while VAS in the ODHM group was higher compared to the TS in the long time procedure (>100 s), as assessed by both patients and doctors.

CONCLUSION

A single use of ODHM seems to be superior to three doses of TS in patients undergoing EFL, specifically in procedures longer than 100seconds.

Microneedle-based drug and vaccine delivery via nanoporous microneedle arrays

In the literature, several types of microneedles have been extensively described. However, porous microneedle arrays only received minimal attention. Hence, only little is known about drug delivery via these microneedles. However, porous microneedle arrays may have potential for future microneedle-based drug and vaccine delivery and could be a valuable addition to the other microneedle-based drug delivery approaches. To gain more insight into porous microneedle technologies, the scientific and patent literature is reviewed, and we focus on the possibilities and constraints of porous microneedle technologies for dermal drug delivery. Furthermore, we show preliminary data with commercially available porous microneedles and describe future directions in this field of research.

Application of a three-microneedle device for the delivery of local anesthetics

PURPOSE

We investigated the effectiveness of a newly developed device for the delivery of local anesthetics in the treatment of axillary osmidrosis and hyperhidrosis. We developed a device with three fine, stainless steel needles fabricated with a bevel angle facing outside ("three-microneedle device" [TMD]) to release a drug broadly and homogeneously into tissue in the horizontal plane. Use of this device could reduce the risk of complications when transcutaneous injections are undertaken.

PATIENTS AND METHODS

Sixteen Japanese patients were enrolled. The mean volume of lidocaine hydrochloride per unit area needed to elicit anesthesia when using a TMD was compared with that the volume required when using a conventional 27-gauge needle. The visual analog scale (VAS) score of needlestick pain and injection-associated pain was also compared.

RESULTS

The mean volume of lidocaine hydrochloride per unit area to elicit anesthesia using the TMD was significantly lower than that the volume required when using the conventional 27-gauge needle. The VAS score of needlestick pain for the TMD was significantly lower than that the VAS score for the 27-gauge needle.

CONCLUSION

These data suggest that the TMD could be useful for the delivery of local anesthetics in terms of clinical efficacy and avoidance of adverse effects.

Microneedles for drug and vaccine delivery

Microneedles were first conceptualized for drug delivery many decades ago, but only became the subject of significant research starting in the mid-1990's when microfabrication technology enabled their manufacture as (i) solid microneedles for skin pretreatment to increase skin permeability, (ii) microneedles coated with drug that dissolves off in the skin, (iii) polymer microneedles that encapsulate drug and fully dissolve in the skin and (iv) hollow microneedles for drug infusion into the skin. As shown in more than 350 papers now published in the field, microneedles have been used to deliver a broad range of different low molecular weight drugs, biotherapeutics and vaccines, including published human studies with a number of small-molecule and protein drugs and vaccines. Influenza vaccination using a hollow microneedle is in widespread clinical use and a number of solid microneedle products are sold for cosmetic purposes. In addition to applications in the skin, microneedles have also been adapted for delivery of bioactives into the eye and into cells. Successful application of microneedles depends on device function that facilitates microneedle insertion and possible infusion into skin, skin recovery after microneedle removal, and drug stability during manufacturing, storage and delivery, and on patient outcomes, including lack of pain, skin irritation and skin infection, in addition to drug efficacy and safety. Building off a strong technology base and multiple demonstrations of successful drug delivery, microneedles are poised to advance further into clinical practice to enable better pharmaceutical therapies, vaccination and other applications.

Adjuvants to prolong the local anesthetic effects of coated microneedle products

The objective of this study was to identify an adjuvant for anesthetics coated on microneedles to provide rapid onset and prolonged analgesic action with minimal skin tissue reaction. Aqueous lidocaine or prilocaine formulations with or without clonidine or the related analogs, guanfacine and apraclonidine, were dip-coated onto polymeric microneedles. The amount of lidocaine or prilocaine coated onto the microneedles was assessed by high performance liquid chromatography (HPLC). Delivery efficiency and dermal pharmacokinetics associated with lidocaine or prilocaine delivered via the microneedles were characterized in vivo using domestic swine. Skin punch biopsies were collected and analyzed to determine the anesthetic concentrations in the skin using HPLC-mass spectrometry (LC-MS). Addition of clonidine to the formulations decreased the systemic absorption rate of the anesthetics from the patch application site without impacting the coating performance or the rapid onset of anesthesia. Formulations with 0.3 wt.% clonidine, identified as the optimal dose for lidocaine-delivery via microneedles, maintained the lidocaine skin concentration above the estimated therapeutic level (100 ng/mg) for 1 h without causing any skin irritation or color change. The other two clonidine analogs, guanfacine and apraclonidine, also led to delayed systemic absorption of lidocaine from the skin, indicating utility in providing prolonged analgesia.

Microneedle delivery: clinical studies and emerging medical applications

The concept of microneedle drug delivery was described three decades ago; however, effective clinical demonstration has only occurred within the past 10–15 years. Substantial progress in microneedle design and fabrication including extensive in vitro, ex vivo, and in vivo preclinical evaluation with various drugs, vaccines and other agents has transpired over the last decade. In contrast with this large volume of preclinical data, there are relatively few published microneedle clinical studies. To date, the clinical investigative focus has included testing to reduce dermal barrier properties and enhance transdermal delivery; evaluation of enhanced vaccine antigenicity, including development of the first commercial microneedle product for intradermal influenza vaccination; evaluation of altered microneedle protein pharmacokinetics and pharmacodynamics, especially for insulin; and evaluation of the pain and other perceptions associated with microneedle usage. This review summarizes the various aspects of microneedle clinical evaluation to date and identifies areas requiring further clinical evaluation.

Kinetics of skin resealing after insertion of microneedles in human subjects

Over the past decade, microneedles have been shown to dramatically increase skin permeability to a broad range of compounds by creating reversible microchannels in the skin. However, in order to achieve sustained transdermal drug delivery, the extent and duration of skin's increased permeability needs to be determined. In this study, we used electrical impedance spectroscopy to perform the first experiments in human subjects to analyze the resealing of skin's barrier properties after insertion of microneedles. Microneedles having a range of geometries were studied in conjunction with the effect of occlusion to test the hypothesis that increasing microneedle length, number, and cross-sectional area together with occlusion leads to an increase in skin resealing time that can exceed one day. Results indicated that in the absence of occlusion, all microneedle treated sites recovered barrier properties within 2 h, while occluded sites resealed more slowly, with resealing windows ranging from 3 to 40 h depending on microneedle geometry. Upon subsequent removal of occlusion, the skin barrier resealed rapidly. Longer microneedles, increased number of needles, and larger cross-sectional area demonstrated slower resealing kinetics indicating that microneedle geometry played a significant role in the barrier resealing process. Overall, this study showed that pre-treatment of skin with microneedles before applying an occlusive transdermal patch can increase skin permeability for more than one day, but nonetheless allow skin to reseal rapidly after patch removal.