A high-dosage microneedle for programmable lidocaine delivery and enhanced local long-lasting analgesia

Indocyanine green-mediated photothermal release of lidocaine from genipin-crosslinked gelatin hydrogel in nerve block

Local anesthetic (LA)-induced peripheral nerve block (PNB) is an important part of multimodal analgesia to reduce postoperative pain, accelerate postoperative recovery, and improve clinical prognosis. The duration of LA depends on anesthetics, and the repeated nerve positioning, puncture injection or indwelling catheter is often required to prolong the effect of PNB. In this study, the genipin, was used to crosslink gelatin-based hydrogel, and then co-loaded with indocyanine green (ICG) and lidocaine as an LA-controlled release system (ICG@Lido/Gel and ICG@Lido/gGel). The viscosity of the genipin-crosslinked gelatin hydrogel (gGel) could be controlled by the genipin/gelatin ratio to achieve the slow release of lidocaine. The ICG@Lido/Gel and ICG@Lido/gGel were biocompatible, and could reduce the instant concentration of lidocaine to minimize its direct cytotoxicity. The ICG@Lido/Gel and ICG@Lido/gGel could increase the PNB period to 70.8 min and 77.8 min, respectively. After NIR exposure, the PNB was introduced again and sustained to 20.8 min for ICG@Lido/Gel and 31.7 min for ICG@Lido/gGel. Therefore, the ICG@Lido/gGel could significantly prolong the PNB duration via increasing the residence time of lidocaine at the injection site, slowing the lidocaine release, and triggering the lidocaine release by NIR exposure. The ICG@Lido/gGel may expresses potential as a photothermal-triggered release system for PNB.

Microneedles: multifunctional devices for drug delivery, body fluid extraction, and bio-sensing

Microneedles represent a miniaturized mechanical structure with versatile applications, including transdermal drug delivery, vaccination, body-fluid extraction, and bio-sensing. Over the past two decades, microneedle-based devices have garnered considerable attention in the biomedicine field, exhibiting the potential for mitigating patient discomfort, enhancing treatment adherence, avoiding first-pass effects, and facilitating precise therapeutic interventions. As an application-oriented technology, the innovation of microneedles is generally carried out in response to a specific demand. Currently, three most common applications of microneedles are drug delivery, fluid extraction, and bio-sensing. This review focuses on the progress in the materials, fabrication techniques, and design of microneedles in recent years. On this basis, the progress and innovation of microneedles in the current research stage are introduced in terms of their three main applications.

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

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

Microneedle patches incorporating zinc-doped mesoporous silica nanoparticles loaded with betamethasone dipropionate for psoriasis treatment

Treating psoriasis presents a major clinical challenge because of the limitations associated with traditional topical glucocorticoid therapy. This study introduced a drug delivery system utilizing zinc-doped mesoporous silica nanoparticle (Zn-MSN) and microneedle (MN), designed to enhance drug utilization for prolonged anti-inflammatory and anti-itch effects. The MN system facilitated the transdermal delivery of betamethasone dipropionate (BD), allowing its slow release. The BD@Zn-MSN-MN system promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype, achieving superior anti-inflammatory effects compared to the clinically used BD cream. Additionally, this study demonstrated that BD@Zn-MSN-MN could further alleviate itching in psoriasis-afflicted mice by decreasing the excitability of the transient receptor potential vanilloid V1 (TRPV1) ion channel positive neurons and reducing the release of calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG). These findings offer new insights and effective therapeutic options for the future design of transdermal drug delivery for psoriasis.

Microneedle-mediated drug delivery for neurological diseases

Neurological disorders, including brain injury, brain tumors, and neurodegenerative diseases, rank as the second leading cause of death worldwide. Exploring effective new treatments for neurological disorders has long been a hot research issue in clinical practice. Recently, microneedles (MNs) have attracted much attention due to their designation as a "painless and non-invasive" novel transdermal delivery method, characterized by their biocompatibility and sustainability. The advantages of MNs open an avenue for potential therapeutic interventions targeting neurological disorders. This review presents a concise overview of progress in the field of MNs, with highlights on the application in the treatment of neurological disorders. Notably, trends in the development of MNs and future challenges are also discussed.

Development of ropivacaine hydrochloride-loaded dissolving microneedles as a local anesthetic agent: A proof-of-concept

Ropivacaine hydrochloride (RPL) is a local anesthetic agent that has been widely used for the treatment of pain during or after surgery. However, this drug is only available in parenteral dosage form and may contribute to the infiltration of RPL into the plasma, causing some undesirable side effects. Intradermal delivery of RPL using dissolving microneedles may become a promising strategy to deliver such drugs into the skin. This research aimed to develop RPL-loaded dissolving microneedles (DMN-RPLs) as a proof of the concept of intradermal delivery of a local anesthetic. The DMN-RPLs were fabricated using either centrifugation or air-pressurized chamber methods. Several polymers, such as poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), and sodium hyaluronate (SH), were utilized for manufacturing the DMN-RPLs. The prepared DMN-RPLs were assessed for their thermal properties, chemical bonds, mechanical strength, insertion ability, skin-dissolution study, and drug content. Furthermore, in-skin deposition and dermatokinetic studies were also performed. The results showed that F9 (30 % w/w PVP-4 % w/w SH) and F10 (30 % w/w PVP-5 % w/w PVA) containing 5 % w/w of RPL were the most promising formulations, as shown by their needle height reduction (<10 %) and insertion depth (∼400 μm). Both formulations were also able to deliver more than 60 % of the RPL contained in the DMNs into the epidermis, dermis, and receiver compartment. This study, for the first time, has provided a proof concept to deliver RPL as a local anesthetic using DMNs and the intradermal route, aiming to minimize pain and discomfort during administration and improve the patient's experience.

Application of hydrogel microneedles in the oral cavity

Microneedles are a transdermal drug delivery system in which the needle punctures the epithelium to deliver the drug directly to deep tissues, thus avoiding the influence of the first-pass effect of the gastrointestinal tract and minimizing the likelihood of pain induction. Hydrogel microneedles are microneedles prepared from hydrogels that have good biocompatibility, controllable mechanical properties, and controllable drug release and can be modified to achieve environmental control of drug release in vivo. The large epithelial tissue in the oral cavity is an ideal site for drug delivery via microneedles. Hydrogel microneedles can overcome mucosal hindrances to delivering drugs to deep tissues; this prevents humidity and a highly dynamic environment in the oral cavity from influencing the efficacy of the drugs and enables them to obtain better therapeutic effects. This article analyzes the materials and advantages of common hydrogel microneedles and reviews the application of hydrogel microneedles in the oral cavity.

Multifunctional fucoidan-loaded Zn-MOF-encapsulated microneedles for MRSA-infected wound healing

Infected wound healing remains a challenging task in clinical practice due to several factors: (I) drug-resistant infections caused by various pathogens, (II) persistent inflammation that hinders tissue regeneration and (III) the ability of pathogens to persist intracellularly and evade antibiotic treatment. Microneedle patches (MNs), recognized for their effecacious and painless subcutaneous drug delivery, could greatly enhance wound healing if integrated with antibacterial functionality and tissue regenerative potential. A multifunctional agent with subcellular targeting capability and contained novel antibacterial components, upon loading onto MNs, could yield excellent therapeutic effects on wound infections. In this study, we sythesised a zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) loaded with low molecular weight fucoidan (Fu) and further coating by hyaluronic acid (HA), obtained a multifunctional HAZ@Fu NPs, which could hinders Methicillin-resistant Staphylococcus aureus (MRSA) growth and promotes M2 polarization in macrophages. We mixed HAZ@Fu NPs with photocrosslinked gelatin methacryloyl (GelMA) and loaded it into the tips of the MNs (HAZ@Fu MNs), administered to mice model with MRSA-infected full-thickness cutaneous wounds. MNs are able to penetrate the skin barrier, delivering HAZ@Fu NPs into the dermal layer. Since cells within infected tissues extensively express the HA receptor CD44, we also confirmed the HA endows the nanoparticles with the ability to target MRSA in subcellular level. In vitro and in vivo murine studies have demonstrated that MNs are capable of delivering HAZ@Fu NPs deep into the dermal layers. And facilitated by the HA coating, HAZ@Fu NPs could target MRSA surviving at the subcellular level. The effective components, such as zinc ions, Fu, and hyaluronic acid could sustainably released, which contributes to antibacterial activity, mitigates inflammation, promotes epithelial regeneration and fosters neovascularization. Through the RNA sequencing of macrophages post co-culture with HAZ@Fu, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis reveals that the biological functionalities associated with wound healing could potentially be facilitated through the PI3K-Akt pathway. The results indicate that the synergistic application of HAZ@Fu NPs with biodegradable MNs may serve as a significant adjunct in the treatment of infected wounds. The intricate mechanisms driving its biological effects merit further investigation.

HPMC/PVP K90 Dissolving Microneedles Fabricated from 3D-Printed Master Molds: Impact on Microneedle Morphology, Mechanical Strength, and Topical Dissolving Property

Three-dimensional (3D) printing can be used to fabricate custom microneedle (MN) patches instead of the conventional method. In this work, 3D-printed MN patches were utilized to fabricate a MN mold, and the mold was used to prepare dissolving MNs for topical lidocaine HCl (L) delivery through the skin. Topical creams usually take 1-2 h to induce an anesthetic effect, so the delivery of lidocaine HCl from dissolving MNs can allow for a therapeutic effect to be reached faster than with a topical cream. The dissolving-MN-patch-incorporated lidocaine HCl was constructed from hydroxypropyl methylcellulose (HPMC; H) and polyvinyl pyrrolidone (PVP K90; P) using centrifugation. Additionally, the morphology, mechanical property, skin insertion, dissolving behavior, drug-loading content, drug release of MNs and the chemical interactions among the compositions were also examined. H51P2-L, H501P2-L, and H901P2-L showed an acceptable needle appearance without bent tips or a broken structure, and they had a low % height change (<10%), including a high blue-dot percentage on the skin (>80%). These three formulations exhibited a drug-loading content approaching 100%. Importantly, the composition-dependent dissolving abilities of MNs were revealed. Containing the lowest amount of HPMC in its formulation, H901P2-L showed the fastest dissolving ability, which was related to the high amount of lidocaine HCl released through the skin. Moreover, the results of an FTIR analysis showed no chemical interactions among the two polymers and lidocaine HCl. As a result, HPMC/PVP K90 dissolving microneedles can be used to deliver lidocaine HCl through the skin, resulting in a faster onset of anesthetic action.

Ropivacaine-loaded hydrogels for prolonged relief of chemotherapy-induced peripheral neuropathic pain and potentiated chemotherapy

Chemotherapy can cause severe pain for patients, but there are currently no satisfactory methods of pain relief. Enhancing the efficacy of chemotherapy to reduce the side effects of high-dose chemotherapeutic drugs remains a major challenge. Moreover, the treatment of chemotherapy-induced peripheral neuropathic pain (CIPNP) is separate from chemotherapy in the clinical setting, causing inconvenience to cancer patients. In view of the many obstacles mentioned above, we developed a strategy to incorporate local anesthetic (LA) into a cisplatin-loaded PF127 hydrogel for painless potentiated chemotherapy. We found that multiple administrations of cisplatin-loaded PF127 hydrogels (PFC) evoked severe CIPNP, which correlated with increased pERK-positive neurons in the dorsal root ganglion (DRG). However, incorporating ropivacaine into the PFC relieved PFC-induced CIPNP for more than ten hours and decreased the number of pERK-positive neurons in the DRG. Moreover, incorporating ropivacaine into the PFC for chemotherapy is found to upregulate major histocompatibility complex class I (MHC-I) expression in tumor cells and promote the infiltration of cytotoxic T lymphocytes (CD8+ T cells) in tumors, thereby potentiating chemotherapy efficacy. This study proposes that LA can be used as an immunemodulator to enhance the effectiveness of chemotherapy, providing new ideas for painless cancer treatment.

Qiqilian ameliorates vascular endothelial dysfunction by inhibiting NLRP3-ASC inflammasome activation in vivo and in vitro

CONTEXT

Previous studies have highlighted significant therapeutic effects of Qiqilian (QQL) capsule on hypertension in spontaneously hypertensive rats (SHRs); however, its underlying molecular mechanism remains unclear.

OBEJECTIVE

We investigated the potential mechanism by which QQL improves hypertension-induced vascular endothelial dysfunction (VED).

MATERIALS AND METHODS

In vivo, SHRs were divided into four groups (20 per group) and were administered gradient doses of QQL (0, 0.3, 0.6, and 1.2 g/kg) for 8 weeks, while Wistar Kyoto rats were used as normal control. The vascular injury extent, IL-1β and IL-18 levels, NLRP3, ASC and caspase-1 contents were examined. In vitro, the effects of QQL-medicated serum on angiotensin II (AngII)-induced inflammatory and autophagy in human umbilical vein endothelial cells (HUVECs) were assessed.

RESULT

Compared with the SHR group, QQL significantly decreased thickness (125.50 to 105.45 μm) and collagen density (8.61 to 3.20%) of arterial vessels, and reduced serum IL-1β (96.25 to 46.13 pg/mL) and IL-18 (345.01 to 162.63 pg/mL) levels. The NLRP3 and ACS expression in arterial vessels were downregulated (0.21- and 0.16-fold, respectively) in the QQL-HD group compared with the SHR group. In vitro, QQL treatment restored NLRP3 and ASC expression, which was downregulated approximately 2-fold compared with that of AngII-induced HUVECs. Furthermore, QQL decreased LC3II and increased p62 contents (p < 0.05), indicating a reduction in autophagosome accumulation. These effects were inhibited by the autophagy agonist rapamycin and enhanced by the autophagy inhibitor chloroquine.

CONCLUSION

QQL effectively attenuated endothelial injury and inflammation by inhibiting AngII-induced excessive autophagy, which serves as a potential therapeutic strategy for hypertension.

Hydrogel-Based Microneedle as a Drug Delivery System

The skin is considered the largest and most accessible organ in the human body, and allows the use of noninvasive and efficient strategies for drug administration, such as the transdermal drug delivery system (TDDS). TDDSs are systems or patches, with the ability and purpose to deliver effective and therapeutic doses of drugs through the skin. Regarding the specific interaction between hydrogels (HG) and microneedles (MNs), we seek to find out how this combination would be applied in the context of drug delivery, and we detail some possible advantages of the methods used. Depending on the components belonging to the HG matrix, we can obtain some essential characteristics that make the combination of hydrogels-microneedles (HG-MNs) very advantageous, such as the response to external stimuli, among others. Based on multiple characteristics provided by HGMNs that are depicted in this work, it is possible to obtain unique properties that include controlled, sustained, and localized drug release, as well as the possibility of a synergistic association between the components of the formulation and the combination of more than one bioactive component. In conclusion, a system based on HG-MNs can offer many advantages in the biomedical field, bringing to light a new technological and safe system for improving the pharmacokinetics and pharmacodynamics of drugs and new treatment perspectives.

Dissolving and Swelling Hydrogel-Based Microneedles: An Overview of Their Materials, Fabrication, Characterization Methods, and Challenges

Polymeric hydrogels are a complex class of materials with one common feature-the ability to form three-dimensional networks capable of imbibing large amounts of water or biological fluids without being dissolved, acting as self-sustained containers for various purposes, including pharmaceutical and biomedical applications. Transdermal pharmaceutical microneedles are a pain-free drug delivery system that continues on the path to widespread adoption-regulatory guidelines are on the horizon, and investments in the field continue to grow annually. Recently, hydrogels have generated interest in the field of transdermal microneedles due to their tunable properties, allowing them to be exploited as delivery systems and extraction tools. As hydrogel microneedles are a new emerging technology, their fabrication faces various challenges that must be resolved for them to redeem themselves as a viable pharmaceutical option. This article discusses hydrogel microneedles from a material perspective, regardless of their mechanism of action. It cites the recent advances in their formulation, presents relevant fabrication and characterization methods, and discusses manufacturing and regulatory challenges facing these emerging technologies before their approval.

Multifunctional Covalent Organic Framework-Based Microneedle Patch for Melanoma Treatment

Melanoma is resistant to conventional chemotherapy and radiotherapy. Therefore, it is essential to develop a targeted, low-toxic, and minimally invasive treatment. Here, DTIC/ICG-Fe3O4@TpBD BSP/HA microneedles (MNs) were designed and fabricated, which can enhance targeting to melanoma and perform photothermal therapy (PTT) and chemotherapy simultaneously to synergistically exert anticancer effects. The system consisted of magnetic nanoparticles (DTIC/ICG-Fe3O4@TpBD), dissoluble matrix (Bletilla polysaccharide (BSP)/hyaluronic acid (HA)), and a polyvinyl alcohol backing layer. Due to the good magnetic responsiveness of Fe3O4@TpBD, dacarbazine (DTIC) and indocyanine green (ICG) can be better targeted to the tumor tissue and improve the therapeutic effect. BSP and HA have good biocompatibility and transdermal ability, so that the MNs can completely penetrate the tumor tissue, be dissolved by the interstitial fluid, and release DTIC and ICG. Under near-infrared (NIR) light irradiation, ICG converts light energy into thermal energy and induces ablation of B16-OVA melanoma cells. In vivo results showed that DTIC/ICG-Fe3O4@TpBD BSP/HA MNs combined with chemotherapy and PTT could effectively inhibit the growth of melanoma without tumor recurrence or significant weight loss in mice. Therefore, DTIC/ICG-Fe3O4@TpBD BSP/HA MNs are expected to provide new ideas and therapeutic approaches for the clinical treatment of melanoma.

Flexible Monitoring, Diagnosis, and Therapy by Microneedles with Versatile Materials and Devices toward Multifunction Scope

Microneedles (MNs) have drawn rising attention owing to their merits of convenience, noninvasiveness, flexible applicability, painless microchannels with boosted metabolism, and precisely tailored multifunction control. MNs can be modified to serve as novel transdermal drug delivery, which conventionally confront with the penetration barrier caused by skin stratum corneum. The micrometer-sized needles create channels through stratum corneum, enabling efficient drug delivery to the dermis for gratifying efficacy. Then, incorporating photosensitizer or photothermal agents into MNs can conduct photodynamic or photothermal therapy, respectively. Besides, health monitoring and medical detection by MN sensors can extract information from skin interstitial fluid and other biochemical/electronic signals. Here, this review discloses a novel monitoring, diagnostic, and therapeutic pattern by MNs, with elaborate discussion about the classified formation of MNs together with various applications and inherent mechanism. Hereby, multifunction development and outlook from biomedical/nanotechnology/photoelectric/devices/informatics to multidisciplinary applications are provided. Programmable intelligent MNs enable logic encoding of diverse monitoring and treatment pathways to extract signals, optimize the therapy efficacy, real-time monitoring, remote control, and drug screening, and take instant treatment.

Fabrication and optimization of 3D printed gelatin methacryloyl microneedle arrays based on vat photopolymerization

Microneedles (MNs) are micrometer-sized arrays that can penetrate the skin in a minimally invasive manner; these devices offer tremendous potential for the transdermal delivery of therapeutic molecules. Although there are many conventional techniques for manufacturing MNs, most of them are complicated and can only fabricate MNs with specific geometries, which restricts the ability to adjust the performance of the MNs. Herein, we present the fabrication of gelatin methacryloyl (GelMA) MN arrays using the vat photopolymerization 3D printing technique. This technique allows for the fabrication of high-resolution and smooth surface MNs with desired geometries. The existence of methacryloyl groups bonded to the GelMA was verified by ¹H NMR and FTIR analysis. To examine the effects of varying needle heights (1000, 750, and 500 µm) and exposure times (30, 50, and 70 s) on GelMA MNs, the height, tip radius, and angle of the needles were measured; their morphological and mechanical properties were also characterized. It was observed that as the exposure time increased, the height of the MNs increased; moreover, sharper tips were obtained and tip angles decreased. In addition, GelMA MNs exhibited good mechanical performance with no breakage up to 0.3 mm displacement. These results indicate that 3D printed GelMA MNs have great potential for transdermal delivery of various therapeutics.

Advances in dermatological application of GelMA hydrogel microneedles

BACKGROUND

Compared with systemic administration methods like injection and oral administration, traditional transdermal drug delivery has the advantages of rapid onset of activity and low side effects. However, hydrophilic drugs and bioactive substances are often unsuitable for traditional transdermal drug delivery.

METHODS

The application of microneedles made from gelatin methylacryloyl (GelMA) has greatly expanded thepossibilities for skin transdermal drug delivery. We have reviewed the latest literatures about the dermatological application of GelMA hydrogel microneedles in recent years using Google Scholar, PubMed and Springer.

RESULTS

GelMA hydrogel microneedles exhibit huge potency in the diagnosis and treatment of skin diseases, and this technology also brings broad application prospects for subcutaneous micro-invasive transdermal targeted drug delivery, which mainly used in skin tissue fluid collection, local substance delivery and wound healing.

CONCLUSION

With in-depth research on GelMA hydrogel, this technology will bring more breakthroughs and developments in the clinical diagnosis and treatment of skin diseases.

Subcutaneous Implantable Microneedle System for the Treatment of Alzheimer's Disease by Delivering Donepezil

To alleviate the dilemma of drug administration in Alzheimer's disease (AD) patients, it is of great significance to develop a new drug delivery system. In this study, a subcutaneously implanted microneedle (MN) device with a swellable gelatin methacryloyl (GelMA) needle body and a dissolvable polyvinyl alcohol (PVA) backing layer was designed. The backing layer quickly dissolved once the MN was introduced into the subcutaneous, and the hydrogel needles were implanted in the subcutaneous to enable prolonged drug release. Compared with oral administration, the MN system offers the benefits of a high administration rate, a fast onset of effect, and a longer duration of action. By detecting the concentration of acetylcholine (ACH) and Aβ 1-42, it was found that MN administration exhibited a stronger therapeutic effect. The biological safety of the MN system was also assessed, and no obvious signs of hemolysis, cytotoxicity, and inflammatory reaction were observed. Together, these findings suggested that the MN system is a convenient, efficient, and safe method of delivering donepezil hydrochloride (DPH) and may provide AD patients with a novel medicine administration option.

Lidosomes: Innovative Vesicular Systems Prepared from Lidocaine Surfadrug

Lidocaine is a local anaesthetic drug with an amphiphilic structure able to self-associate, under certain conditions, in molecular aggregates playing the role of both carrier and drug. The aim of this study was to determine the optimal conditions for obtaining vesicular carriers, called lidosomes. The new formulations were obtained using both lidocaine and lidocaine hydrochloride and different hydration medias (distilled water, acid, and basic aqueous solution). Lidosomes formulations were characterized in terms of size, ζ-potential, drug retained, stability formulation, and ex vivo permeation profile. Moreover, lidosomes were incorporated in two different gel structures: one based on carboxymethylcellulose and one based on pluronic F-127 to achieve suitable properties for a topical application. Results obtained showed that lidocaine showed a better performance to aggregate in vesicular carriers in respect to hydrochloride form. Consequently, only formulations comprised of lidocaine were studied in terms of skin permeation performance and as carriers of another model drug, capsaicin, for a potential combined therapy. Lidocaine, when in form of vesicular aggregates, acted as percutaneous permeation enhancer showing better permeation profiles with respect to drug solutions. Moreover, lidosomes created a significant drug depot into the skin from which the drug was available for a prolonged time, a suitable feature for a successful local therapy.