Hydrogel forming microneedle-mediated transdermal delivery of sildenafil citrate from polyethylene glycol reservoir: An ex vivo proof of concept study

Validation of spectrophotometric and colorimetric method for the specific quantification of sofosbuvir From luminar capsule microneedle in liver tissue through ex vivo and in vivo applications

An antiviral prodrug that has received regulatory approval and primarily employed in the treatment of hepatitis C is sofosbuvir (SOF). It is therefore imperative to develop advanced delivery methods for SOF in order to address existing absor ption issue and maximize the efficacy. In this study, we developed microneedle-integrated SOF (MN-SOF) which were elongated with branches and coated capsules to form luminar capsule microneedles (LUCAMs). To facilitate the formulation of LUCAMs, analytical methods for SOF in ethanol, artificial intestinal fluid (AIF), and artificial gastric fluid (AGF) were developed using a UV-vis spectrophotometer and colorimetric techniques in liver tissue. These methods were validated by combi ning the samples with ammonium metavanadate reagent. The validation process was conducted in order to ensure the accuracy, precision, linearity, specificity, and sensitivity of the methods. These methods exhibited a correlation coefficient of 0.9999, with a coefficient of variation below 25%. The methods demonstrate high accuracy and precision, with relative standard deviation (RSD) values ranging from 0.67% to 9.42% across different medium. The limit of detection (LOD) and limit of quantification (LOQ) values of SOF on each calibration curve of ethanol, artificial gastric fluid (AGF), artificial intestinal fluid (AIF), and rabbit liver tissue are 0.54μg/mL and 1.65μg/mL; 0.54μg/mL and 1.64μg/mL; 0.39μg/mL and 1.21μg/mL; 0.27μg/mL and 0.83μg/mL. As a significant outcome, the analytical method was validated and demonstrated suitability for determining the amount of SOF in the LUCAMs formulation through in vitro solubility, ex vivo permeation profiles, and in vivo drug delivery studies.

Controlled release of deferiprone using iron-responsive nanoparticles integrated with dissolving microneedle for novel alternative treatments of β-thalassemia major

Iron chelating agents (ICs) such as conventional deferiprone are often ineffective when exposed to normal conditions due to their uncontrolled release when treating iron overload in ß-thalassemia major (ß-TM) due to the effects of blood transfusion. Iron deficiency and gastrointestinal side effects are crucial problems that can occur. Therefore, DFP was prepared as nanoparticles (NPs) coated with an iron-responsive (IR) polymer with an average particle size of 354.70 ± 10 nm to control its release. To facilitate optimal delivery, NP-IR-DFP was integrated into a dissolving microneedle (DMN) fabricated with biodegradable and biocompatible poly(vinylpyrrolidone) and poly(vinyl alcohol) polymers. The results showed that the NP-IR-DMN provided excellent insertion and mechanical strength and dissolved quickly after application. In vitro and ex-vivo studies revealed the more controllable release of NP-IR-DFP after integration with the DMN (NP-IR-DMN) for up to 24 h. Most importantly, the developed formula was hemocompatible and did not irritate the skin or cause tissue damage. Furthermore, the in vivo pharmacokinetics were further investigated for 24 h, which revealed short concentration (Cmax of 0.07 ± 0.03 μg/mL) and t1/2 (3.66 ± 0.76 h) under normal conditions and long-term iron overload-modeling conditions with Cmax (2.90 ± 0.14 μg/mL) and t1/2 (10.13 ± 1.00 h). This approach can extend beyond oral delivery by controlling the release of DFP, which can only be released in conditions of iron overload, and has the potential to prevent iron deficiency and excess, thus increasing the efficacy of DFP in β-TM therapy.

Ethyl cellulose-based in-situ film of itraconazole for enhanced treatment of fungal infections

OBJECTIVES

Fungal infections represent a significant global health challenge, requiring effective treatments to prevent complications and improve patient outcomes. This study aimed to develop an in-situ film-forming system (IFFS) for transcutaneous delivery of itraconazole (ITZ) as an alternative to oral administration, addressing issues such as low bioavailability, reduced efficacy, and potential side effects.

MATERIALS AND METHODS

The IFFS was formulated using ethyl cellulose as the primary polymer, PEG 400 as a plasticizer, and a eutectic mixture of menthol and camphor as penetration enhancers. The system was characterized for viscosity, pH, drying time, water vapor permeability, bioadhesion, and physicochemical interactions (DSC and FTIR). Ex vivo skin permeation and retention studies were conducted using Franz diffusion cells, and antifungal efficacy was tested on an ex vivo Candida albicans infection model. Skin integrity and hemolysis tests were performed to evaluate safety.

RESULTS

The IFFS exhibited desirable physicochemical properties, with increased polymer concentrations enhancing skin retention and bioadhesive strength while reducing permeation rates. Ex vivo studies showed sustained ITZ release and enhanced skin retention. The antifungal activity test demonstrated complete eradication of Candida albicans within 48hours. Safety assessments confirmed no skin irritation or toxicity.

CONCLUSION

The developed IFFS provides a safe and effective transcutaneous delivery system for ITZ. This innovative approach enhances antifungal efficacy, improves skin retention, and offers a promising alternative to oral administration, minimizing systemic side effects.

Multifunctional Hydrogel Microneedles (HMNs) in Drug Delivery and Diagnostics

Hydrogel microneedles (HMNs) have emerged as a transformative platform for minimally invasive drug delivery and biosensing, offering enhanced bioavailability, controlled drug release, and real-time biomarker detection. By leveraging swelling hydrogels, nanomaterial integration, and stimuli-responsive properties, HMNs provide precision medicine capabilities across diverse therapeutic and diagnostic applications. However, challenges remain in mechanical stability, as hydrogel-based MNs must balance flexibility with sufficient strength for skin penetration. Drug retention and controlled release require optimization to prevent premature diffusion and ensure sustained therapeutic effects. Additionally, biosensing accuracy is influenced by variability in interstitial fluid extraction and signal transduction. Clinical translation is hindered by regulatory hurdles, scalability concerns, and the need for extensive safety validation in human trials. This review critically examines the key materials, fabrication techniques, functional properties, and testing frameworks of HMNs while addressing these limitations. Furthermore, we explore future research directions in smart wearable MNs, AI-assisted biosensing, and hybrid drug-device platforms to optimize transdermal medicine. Overcoming these barriers will drive the clinical adoption of HMNs, paving the way for next-generation patient-centered therapeutics and diagnostics.

Development of a curcumin-piperine nanoparticle system using dissolving microneedles for transdermal drug delivery in malaria treatment: In vitro evaluation

The combination of the active compounds curcumin and piperine (CP) is effective as an antimalarial; however, the solubility and bioavailability of CP are very low. This study aims to formulate CP in nanoparticles (NP), which are then fabricated into dissolving microneedles (DMN). The NPs were prepared with a concentration ratio of CP-Chitosan-So.TPP-So.Alginate (0.1:0.04:0.02:0.03). Subsequently, NPs-CP-DMN were formulated with NPs-CP concentrations (35:40:50 w/w) and a mixture of the polymers polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) in a ratio of (35:65, 40:60, 50:50). Characterization of the nanoparticles and microneedles was conducted, including dissolution time tests, permeation studies, hemolysis assessment, dermatokinetics, and in vitro antiplasmodial activity testing. The results showed that NPs-CP had an average size of 446.67 ± 40.27 nm and 367.6 ± 26.31 nm. On the formula NPs-CP-DMN the addition of PVA and PVP polymers (F2) resulted in DMNs with good mechanical strength and penetration ability, capable of penetrating five layers of Parafilm®. This formulation completely dissolved in 10 min without leaving any residue, with a curcumin flux value of 25.7 ± 0,51 µg/mL and piperine flux of 28.5 ± 0,51 µg/mL. The formulation showed no toxicity, with a hemolysis percentage of < 5 %, Tmax of 7 h, and Cmax values of 11.07 ± 0.31 µg/cm3 for curcumin and 17.40 ± 3.3 µg/cm3 for piperine. Moreover, this formulation effectively inhibited the P.falciparum FCR3 strain parasite, with an IC50 value of 35.9 μg/mL. Therefore, this study holds promise as a new strategy for malaria treatment.

Development of Pluronic-Based Micelles from Palm Oil Bioactive Compounds Incorporated by a Dissolvable Microarray Patch to Enhance the Efficacy of Atopic Dermatitis Therapy

The high content of vitamin E, including tocopherols and tocotrienols (TCF-TTE), in palm oil (Elaeis guineensis) has made it a promising candidate for the alternative treatment of atopic dermatitis (AD). However, the limited solubility of TCF-TTE has restricted its therapeutic efficacy. In this study, pluronic-based micelles (MCs) encapsulating palm oil-derived TCF-TTE were formulated with dissolvable microarray patch-micelles (DMP-MC) using carboxymethyl cellulose (CMC) synthesized from empty fruit bunches of palm to optimize its delivery for AD. The MC was prepared using a direct dissolution method using Pluronic F68 and F127. The results showed that MC increased the solubility of TCF-TTE, which was further confirmed by an in vitro study where 90.23 ± 2.07% TCF and 4.56 ± 1.36% TTE were released compared to the unencapsulated TCF-TTE extract. Furthermore, CMC biopolymers and MC integrated into DMP-MC with polyvinylpyrrolidone (PVP) exhibited favorable physical properties, such as mechanical strength and penetration ability. DMP-MC also exhibited a better platform with lower permeation, indicating higher retention and increased localized effects on AD skin than cream-MC. Additionally, dermatokinetic profile parameters showed significant improvement. The mean residence time (MRT) parameter indicated that TCF-TTE was retained for longer times 19.28 ± 0.02 h and 20.68 ± 0.01 h. Moreover, an in vivo study revealed that DMP-MC could relieve AD symptoms more rapidly than oral doses and cream-MC, indicating that DMP-MC proved to be more efficient. Furthermore, DMP-MC showed no tissue destruction (granulation and fibrosis) in rats treated with DMP-MC on the seventh day. Therefore, this study successfully developed the MC formula in DMP-MC formulation using synthesized CMC, which could potentially improve AD's therapeutic efficacy.

Development of three-layer microneedle system for controlled and sustained release of Levonorgestrel: A pioneering approach to long-term contraceptive delivery

The increasing prevalence of unintended pregnancies, a persistent issue affecting public health and hindering progress towards the Sustainable Development Goals (SDGs), highlights the critical need for innovative contraceptive approaches. While current methods, including hormonal contraceptives such as levonorgestrel (LNG), offer potential solutions, challenges like limited access and inconsistent use persist. This study introduces a new approach with the development of a three-layer microneedle (TIMN) containing LNG designed to provide extended contraceptive efficacy. The TIMN was formulated with varying concentrations of polyvinylpyrrolidone (PVP) and polycaprolactone (PCL) in the first layer, resulting in microneedles approximately 700 µm in height. In this study, TIMN demonstrated superior mechanical strength with less than 10% reduction in needle height under compression. The formulations maintained a surface pH within the skin's normal range, ensuring safety and compatibility, while water vapor transmission (WVT) values indicated good stability under high humidity. Moisture absorption ability (MAA) testing showed low water absorption, suggesting suitability for extended use. In vitro release studies revealed that TIMN released 28.34% of LNG after 24 h and up to 97.34% over 14 days, demonstrating controlled and sustained release. Ex vivo studies confirmed TIMN's longer-lasting LNG availability compared to the control, and in vivo pharmacokinetic studies showed that TIMN maintained therapeutic LNG levels for up to 14 days, outperforming oral LNG suspension. Biocompatibility tests, including HET-CAM and hemolysis assays, confirmed TIMN's safety, with no significant irritation or toxicity. Histopathological analysis further supported the absence of adverse reactions. The TIMN formulation, exhibits promising properties for long-term drug delivery, including mechanical strength, stability, controlled release, and biocompatibility, making it a viable candidate for improved contraceptive therapy.

The Synergistic Potential of Hydrogel Microneedles and Nanomaterials: Breaking Barriers in Transdermal Therapy

The stratum corneum, which acts as a strong barrier against external agents, presents a significant challenge to transdermal drug delivery. In this regard, microneedle (MN) patches, designed as modern systems for drug delivery via permeation through the skin with the ability to pass through the stratum corneum, are known to be convenient, painless, and effective. In fact, MN have shown significant breakthroughs in transdermal drug delivery, and among the various types, hydrogel MN (HMNs) have demonstrated desirable inherent properties. Despite advancements, issues such as limited loading capacity, uncontrolled drug release rates, and non-uniform therapeutic approaches persist. Conversely, nanomaterials (NMs) have shown significant promise in medical applications, however, their efficacy and applicability are constrained by challenges including poor stability, low bioavailability, limited payload capacity, and rapid clearance by the immune system. Incorporation of NMs within HMNs offers new prospects to address the challenges associated with HMNs and NMs. This combination can provide a promising field of research for improved and effective delivery of therapeutic agents and mitigate certain adverse effects, addressing current clinical concerns. The current review highlights the use of NMs in HMNs for various therapeutic and diagnostic applications.

Development of amphotericin B inclusion complex formulation in dissolvable microarray patches for intravaginal delivery

BACKGROUND

Amphotericin B (AMB) is a drug used to treat vulvovaginal candidiasis (VVC), which is a fungal infection affecting the vagina and vulva. Nevertheless, the substance's limited capacity to dissolve in water leads to poor absorption when taken orally, hence diminishing its therapeutic efficacy. In order to address this limitation, β-cyclodextrin (βCD) was used to create AMB in the form of an inclusion complex.

OBJECTIVE

This study aims to enhance the solubility and bioavailability of AMB by formulating it into an inclusion complex with βCD. Subsequently, we developed dissolvable microarray patches (DMP) as a novel drug delivery system, optimizing the formulation for improved retention, penetration, and controlled release of AMB.

METHODS

The stability of the AMB-βCD inclusion complx (IC) structure has been confirmed by employing molecular docking studies. The formulation of DMP involved the incorporation of IC with polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). The mechanical strength, ability to be inserted, and propensity to irritate Amphotericin B-Inclusion Complex-Dissolvable Microarray Patches (IC-DMP) were evaluated by laboratory experiments utilizing the porcine vaginal mucosal layer. Further investigations, such as Differential Scanning Calorimetry (DSC), were performed to assess the physicochemical characteristics of the IC.

RESULTS

The solubility of the pure medication was greatly enhanced up to fourfold by the inclusion complex. The assessment of IC-DMP exhibited exceptional mechanical robustness and insertion abilities, with no indications of discomfort. Among the formulas tested in ex vivo vaginal kinetic experiments, Formula F3 had the most effective retention in the porcine vaginal mucosal layer. It had an AUC value of 208.02 ± 0.33 h.µg/cm3 and the highest Cmax value of 20.05 ± 0.06 µg/cm3. Therefore, Formula F3 was the most efficient formula in terms of vaginal drug delivery.

CONCLUSION

The integration of IC into the DMP system significantly enhances the solubility and bioavailability of AMB, facilitating its absorption in the circulatory system when applied intravaginally for vulvovaginal candidiasis treatment. These promising initial findings support further clinical evaluation of this novel drug delivery system.

A Combinatorial Approach with Microneedle Pretreatment and Thermosensitive Gel Loaded with Rivastigmine Lipid Nanoparticle Formulation Enables Brain Delivery via the Trigeminal Nerve

Alzheimer's disease (AD) often leads to dementia, causing cognitive decline and increased care needs. Rivastigmine (RV) is a key AD treatment, but its brain delivery is limited by the blood-brain barrier (BBB). Aside from oral, olfactory, and intradermal injection (i.d.) routes, the application of polymeric microneedles via the trigeminal nerve on the facial skin as a pretreatment, followed by a solid lipid nanoparticle RV-loaded thermosensitive gel (PMN-SLN-RV-TG), is an alternative to deal with the problems. This study aims to determine the optimal formula for PMN-SLN-RV-TG application and assess its brain delivery ability compared to conventional routes. The optimum SLN-RV formula had a particle size <200 nm and sustained release for 72 h, which was selected for the SLN-RV-TG formulation. SLN-RV-TG was transformed into a gel at normal skin temperature (32-37 °C), with good physical properties and nontoxic behavior. The ideal PMN formula was able to penetrate the dermal layer as an alternative to i.d. administration. Ex vivo dermatokinetics showed significant improvement of PMN-SLN-RV-TG application (p < 0.05) compared to without PMN application. In vivo pharmacokinetic studies on rats also revealed that the PMN-SLN-RV-TG had superior pharmacokinetic parameters (Cmax, AUC, t1/2, and MRT) compared to other groups (p < 0.05). Radiolabeling SLN-RV with 99mTc showed good physical properties, with a radiochemical yield of >95%. In vivo distribution studies of PMN-SLN-RV-TG application exhibited a higher brain:blood ratio than i.v. administration after 5 h, as well as being safe for the brain due to a good histological profile. These results show that PMN-SLN-RV-TG application via the trigeminal nerve on the facial skin has strong potential delivery to the brain for AD treatment.

Hispidulin-rich fraction of Clerodendrum fragrans Wild. (Sesewanua) dissolving microneedle as antithrombosis candidate: A proof of concept study

Existing conventional antithrombosis drugs have caused many side effects, opening up opportunities for the development of new thrombotic drugs. There is potential to use the hispidulin-rich fraction of sesewanua (HRFS) as a new antithrombotic. The oral route limitation of hispidulin, as a low water solubility and non-polar compound, can be addressed. This study explores the potential of HRFS in the form of dissolving microneedles (DMN). The formula was created using polymers such as polyvinyl alcohol (PVA), polyvinyl pyrrolidone K-30 (PVP), and non-ionic surfactant. Ex vivo permeation studies found that 184.95 µg/cm2 of hispidulin was released 60 h after the best formulation. After 14 days of applying HRFS-DMN, the anticoagulant and antioxidant activity in male albino rats showed higher Activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT) values and lower Inter Cellular Adhesion Molecule-1 (ICAM-1) values. No statistically significant differences were found between the effects of two and four HRFS-DMN and the injection of heparin at a dosage of 200 IU per kilogram. However, notable distinctions were observed when comparing HRFS-DMN to negative controls, oral and quercetin as positive controls at anti-ICAM activity. The findings confirmed the feasibility of HRFS-DMN for thrombosis and its effectiveness in delivering Hispidulin (HIS) into the bloodstream. This DMN is non-irritating, safe, and painless, showing promising outcomes in enhancing the efficacy of thrombosis treatment via the transdermal route.

Hydrogel-Forming Microneedles in the Management of Dermal Disorders Through a Non-Invasive Process: A Review

Microneedle (MN) technology has emerged as a promising approach for delivering therapeutic agents to the skin, offering significant potential in treating various dermal conditions. Among these technologies, hydrogel-forming microneedles (HFMNs) represent a transformative advancement in the management of dermal diseases through non-invasive drug delivery. These innovative devices consist of micrometer-sized needles made of native or crosslinked hydrophilic polymers, capable of penetrating the stratum corneum without damaging underlying tissues. Upon insertion, HFMNs rapidly absorb interstitial fluid, swelling to form a hydrogel conduit that enables the efficient transport of therapeutic agents directly into the dermal microcirculation. The non-invasive nature of HFMNs enhances patient compliance by eliminating the pain and discomfort associated with traditional hypodermic needles. This technology allows for the delivery of a wide range of drugs, including macromolecules and biomacromolecules, which are often difficult to administer dermally due to their size and polarity. Moreover, HFMNs provide controlled and regulated release profiles, enabling sustained therapeutic effects while minimizing systemic side effects. Additionally, HFMNs can be used for both drug delivery and real-time interstitial fluid monitoring, offering valuable insights into disease states and treatment responses. This dual functionality positions HFMNs as a versatile dermatology tool capable of effectively addressing various dermal complications. This review explores the potential use of polymeric biomaterials in HFMN fabrication and their application in treating major dermal disorders, such as acne, psoriasis, and other skin conditions. Furthermore, the review highlights the non-invasive nature of MN-based treatments, underscoring their potential to reduce patient discomfort and improve treatment adherence, as supported by the recent literature.

Development of itraconazole ocular delivery system using β-cyclodextrin complexation incorporated into dissolving microneedles for potential improvement treatment of fungal keratitis

Itraconazole (ITZ) is one of the broad-spectrum antifungal agents for treating fungal keratitis. In clinical use, ITZ has problems related to its poor solubility in water, which results in low bioavailability when administered orally. To resolve the issue, we formulated ITZ into the inclusion complex (ITZ-IC) system using β-cyclodextrin (β-CD), which can potentially increase the solubility and bioavailability of ITZ. The molecular docking study has confirmed that the binding energy of ITZ with the β-CD was -5.0 kcal/mol, indicating a stable conformation of the prepared inclusion complex. Moreover, this system demonstrated that the inclusion complex could significantly increase the solubility of ITZ up to 4-fold compared to the pure drug. Furthermore, an ocular drug delivery system was developed through dissolving microneedle (DMN) using polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) as polymeric substances. The evaluation results of DMN inclusion complexes (ITZ-IC-DMN) showed excellent mechanical strength and insertion ability. In addition, ITZ-IC-DMN can dissolve rapidly upon application. The ex vivo permeation study revealed that 75.71% (equivalent to 3.79 ± 0.21 mg) of ITZ was permeated through the porcine cornea after 24 h. Essentially, ITZ-IC-DMN exhibited no signs of irritation in the HET-CAM study, indicating its safety for application. In conclusion, this study has successfully developed an inclusion complex formulation containing ITZ using β-CD in the DMN system. This approach holds promise for enhancing the solubility and bioavailability of ITZ through ocular administration.

Development of Transdermal Formulation Integrating Polymer-Based Solid Microneedles and Thermoresponsive Gel Fucoidan for Antiaging: Proof of Concept Study

Skin can be damaged by intense and prolonged exposure to ultraviolet (UV) radiation. Photoaging and acute damage from sun exposure result in collagen degradation and enzymatic activity decline in the skin. Fucoidan (FUC) exhibits potential antiaging properties, including collagen synthesis promotion and enzyme activity inhibition. However, FUC's limited ability to penetrate the skin layers due to its large molecular weight makes it a challenge for topical application. In this study, we successfully developed a new approach by integrating thermoresponsive gel (TRG) containing FUC with solid microneedles (SMNs) as a delivery system. TRG is formulated using a combination of Pluronic F127 (PF127) and Pluronic F68 (PF68) polymers, while SMNs are made from a mixture of poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) polymers with a variety of cross-linkers. Based on the results of ex vivo testing, it was shown that more than 80% of FUC can be delivered using the optimized formula. Furthermore, the results of the in vitro blood hemolytic test showed that TRG-FUC-SMNs were relatively biocompatible. In vivo antiaging activity tests using a rat model exposed to UV for 14 days showed that histological assessment, skin elasticity measurement, wrinkle evaluation, and skin moisture content had no significant differences (p < 0.05) compared to the positive control group. In contrast, a significant difference (p < 0.05) was observed when comparing the TRG-FUC-SMNs group with the group that received only TRG-FUC without pretreatment and negative controls. These findings suggest that FUC has potential to be delivered using the TRG system in combination with SMNs to harness its antiaging properties.

Implantable trilayer microneedle transdermal delivery system to enhance bioavailability and brain delivery of rivastigmine for Alzheimer treatment: A proof-of-concept study

Alzheimer's disease (ALZ) is a neurological disorder characterized by cognitive decline. Rivastigmine (RV), an acetylcholinesterase inhibitor, is commonly used to treat ALZ. Unfortunately, RV is availablein capsule form, which is associated with low drug bioavailability, and in patch form, which can lead to skin irritation upon repeated use. This study successfully fabricated a trilayer dissolving microneedle (TDMN) containing RV with adequate mechanical strength by using the molding method. In vitro release and ex vivo permeation showed that the release and permeation of RV were significantly sustained compared to control without PCL. The release and permeation percentages were 91.34 ± 11.39 % and 13.76 ± 1.49 μg/cm2, respectively. In addition, the concentration of RV in plasma and brain after 168 h was measured to be 0.44 ± 0.09 µg/mL and 1.23 ± 0.26 µg/g, respectively, which reached the minimum concentration to inhibit AcHE and BuChe. Pharmacokinetic testing revealed higher AUC values after administration of TDMN, indicating better bioavailability and RV concentrations in the brain were twice as high as those achieved with oral administration. This study suggests TDMN may enhance the bioavailability and brain delivery of RV.

Trilayer dissolving microneedle for transdermal delivery of minoxidil: a proof-of-concept study

Alopecia areata (AA) is a chronic autoimmune disease characterized by bald patches in certain areas of the body, especially the scalp. Minoxidil (MNX), as a first-line treatment of AA, effectively induces hair growth. However, oral and topical administration pose problems, including low bioavailability, risk of uncontrolled hair growth, and local side effects such as burning hair loss, and scalp irritation. In the latest research, MNX was delivered to the skin via microneedle (MN) transdermally. The MNX concentration was distributed throughout the needle so that drug penetration was reduced and had the potential to irritate. In this study, we formulated MNX into three-layer dissolving microneedles (TDMN) to increase drug penetration and avoid irritation. Physicochemical evaluation, parafilm, was used to evaluate the mechanical strength of TDMN and showed that TDMN could penetrate the stratum corneum. The ex-vivo permeation test showed that the highest average permeation result was obtained for TDMN2, namely 165.28 ± 31.87 ug/cm2, while for Minoxidil cream it was 46.03 ± 8.5 ug/cm2. The results of ex vivo and in vivo dermatokinetic tests showed that the amount of drug concentration remaining in the skin from the TDMN2 formula was higher compared to the cream preparation. The formula developed has no potential for irritation and toxicity based on the HET-CAM test and hemolysis test. TDMN is a promising alternative to administering MNX to overcome MNX problems and increase the effectiveness of AA therapy.

Nanocomposite hydrogel microneedles: a theranostic toolbox for personalized medicine

Due to the severity and high prevalence of cancer, as well as its complex pathological condition, new strategies for cancer treatment and diagnostics are required. As such, it is important to design a toolbox that integrates multiple functions on a single smart platform. Theranostic hydrogels offer an innovative and personalized method to tackle cancer while also considering patient comfort, thereby facilitating future implementation and translation to the clinic. In terms of theranostic systems used in cancer therapy, nanoparticles are widely used as diagnostic and therapeutic tools. Nanoparticles can achieve systemic circulation, evade host defenses, and deliver drugs and signaling agents at the targeted site, to diagnose and treat the disease at a cellular and molecular level. In this context, hydrogel microneedles have a high potential for multifunctional operation in medical devices, while avoiding the complications associated with the systemic delivery of therapeutics. Compared with oral administration and subcutaneous injection, microneedles offer advantages such as better patient compliance, faster onset of action, and improved permeability and efficacy. In addition, they comprise highly biocompatible polymers with excellent degradability and tunable properties. Nanoparticles and microneedles thus offer the possibility to expand the theranostic potential through combined synergistic use of their respective features. We review herein recent advances concerning processing methods and material requirements within the realm of hydrogel microneedles as theranostic platforms, various approaches toward cancer therapy, and the incorporation of nanoparticles for added functionality.

Anti-Nociceptive Effect of Sufentanil Polymeric Dissolving Microneedle on Male Mice by Hot Plate Technique

Background

Despite the widespread use of opioids to manage severe pain, its systemic administration results in side effects. Among the subcutaneous and transdermal drug delivery systems developed to deal with adverse effects, microneedles have drawn attention due to their rapid action, high drug bioavailability, and improved permeability. Sufentanil (SUF) is an effective injectable opioid for treating severe pain. In this study, we investigated the analgesic effects of SUF using dissolvable microneedles.

Methods

SUF polymeric dissolvable microneedles were constructed through the mold casting method and characterized by SEM and FTIR analysis. Its mechanical strength was also investigated using a texture analyzer. Fluorescence microscopy was applied in vitro to measure the penetration depth of microneedle arrays. Irritation and microchannel closure time, drug release profile, and hemocompatibility test were conducted for the validation of microneedle efficiency. Hot plate test was also used to investigate the analgesic effect of microneedle in an animal model.

Results

Local administration of SUF via dissolving microneedles had an effective analgesic impact. One hour after administration, there was no significant difference between the subcutaneous and the microneedle groups, and the mechanical properties were within acceptable limits.

Conclusion

Microneedling is an effective strategy in immediate pain relief compared to the traditional methods.

Swellable Microneedles in Drug Delivery and Diagnostics

This manuscript explores the transformative potential of swellable microneedles (MNs) in drug delivery and diagnostics, addressing critical needs in medical treatment and monitoring. Innovations in hydrogel-integrated MN arrays facilitate controlled drug release, thereby expanding treatment options for chronic diseases and conditions that require precise dosage control. The review covers challenges, such as scalability, patient compliance, and manufacturing processes, as well as achievements in advanced manufacturing, biocompatibility, and versatile applications. Nonetheless, limitations in physiological responsiveness and long-term stability remain, necessitating further research in material innovation and integration with digital technologies. Future directions focus on expanding biomedical applications, material advancements, and regulatory considerations for widespread clinical adoption.

Formulation and evaluation of dissolving microneedle for transdermal delivery of piperine: the effect of polymers concentration

This research aims to develop the formulation of Dissolving Microneedle Piperine (DMNs PIP) and evaluate the effect of polymer concentration on characterisation and permeation testing results in ex vivo. DMNs PIP were prepared from varying concentrations of piperine (PIP) (10, 15, and 20% w/w) and polymers of polyvinyl alcohol (PVA): Polyvinyl pyrrolidone (30:60 and 60:25), respectively. Then the morphological evaluation of the formula was carried out, followed by mechanical strength testing. Furthermore, the density, LOD, and weight percentage of piperine in the dried microneedle were calculated and the determination of volume, needle weight and piperine weight and analysed. Ex vivo testing, X-Ray Diffraction, FTIR and hemolysis tests were carried out. PIP with PVA and PVP (F1) polymers produced DMN with mechanical strength (8.35 ± 0.11%) and good penetration ability. In vitro tests showed that the F1 polymer mixture gave good penetration (95.02 ± 1.42 μg/cm2), significantly higher than the F2, F3, F4, and F5 polymer mixtures. The DMNs PIP characterisation results through XRD analysis showed a distinctive peak in the 20-30 region, indicating the presence of crystals. The FTIR study showed that the characteristics of piperine found in DMNs PIP indicated that piperine did not undergo interactions with polymers. The results of the ex vivo study through DMNs PIP hemolytic testing showed no hemolysis occurred, with the hemolysis index below the 5% threshold reported in the literature. These findings indicate that DMNs PIP is non-toxic and safe to use as alternative for treating inflammation.

Integration of metformin-loaded MIL-100(Fe) into hydrogel microneedles for prolonged regulation of blood glucose levels

The transdermal drug delivery based on microneedles (MNs) provides a suitable and painless self-administration for diabetic patients. In this work, the hydrogel-forming MNs were firstly fabricated using poly(vinyl alcohol) (PVA) and chitosan (CS) as matrix. A hypoglycemic drug, metformin (Met), had been loaded into MIL-100(Fe). Then, both of free Met and Met-loaded MIL-100(Fe) were integrated into hydrogel-forming MNs for regulation of blood glucose levels (BGLs) on diabetic rats. After penetrated into the skin, the free Met could be firstly released from MNs. Due to the absorption of interstitial fluid and subsequent release of loaded Met from MIL-100(Fe), leading to a sustainable and long-term drug release behaviors. A notable hypoglycemic effect and low risk of hypoglycemia could be obtained on diabetic rat modelsin vivo. The as-fabricated hydrogel-forming MNs expected to become a new type of transdermal drug delivery platform for transdermal delivery of high-dose drugs to form a long-term hypoglycemic effect.

Selective Delivery of Clindamycin Using a Combination of Bacterially Sensitive Microparticle and Separable Effervescent Microarray Patch on Bacteria Causing Diabetic Foot Infection

INTRODUCTION

Diabetic foot infection (DFI) is one of the complications of diabetes mellitus. Clindamycin (CLY) is one of the antibiotics recommended to treat DFI, but CLY given orally and intravenously still causes many side effects.

METHODS

In this study, we encapsulated CLY in a bacteria sensitive microparticle system (MP-CLY) using polycaprolactone (PCL) polymer. MP-CLY was then delivered in a separable effervescent microarray patch (MP-CLY-SEMAP), which has the ability to separate between the needle layer and separable layer due to the formation of air bubbles when interacting with interstitial fluid in the skin.

RESULT

The characterization results of MP-CLY proved that CLY was encapsulated in large amounts as the amount of PCL polymer used increased, and there was no change in the chemical structure of CLY. In vitro release test results showed increased CLY release in media cultured with Staphylococcus aureus bacteria and showed controlled release. The characterization results of MPCLY-SEMAP showed that the developed formula has optimal mechanical and penetration capabilities and can separate in 56 ± 5.099 s. An ex vivo dermatokinetic test on a bacterially infected skin model showed an improvement of CLY dermatokinetic profile from MP-CLY SEMAP and a decrease in bacterial viability by 99.99%.

CONCLUSION

This research offers proof of concept demonstrating the improved dermatokinetic profile of CLY encapsulated in a bacteria sensitive MP form and delivered via MP-CLY-SEMAP. The results of this research can be developed for future research by testing MP-CLY-SEMAP in vivo in appropriate animal models.

Application of validated UV spectrophotometric and colorimetric method to quantify minoxidil in the development of trilayer dissolving microneedle: Proof of concept in ex vivo and in vivo studies in rats

Alopecia areata (AA) is an autoimmune-induced hair loss condition, by utilizing MNX, a hair growth-promoting compound. However, minoxidil (MNX) administration's efficacy is hindered by low bioavailability and adverse effects. To enhance its delivery, Trilayer Dissolving Microneedles (TDMN) are introduced, enabling controlled drug release. The study's primary was to establish a validated UV-Vis Spectrophotometer method for Minoxidil analysis in rat skin affected by alopecia areata. This method adheres to International Conference Harmonization (ICH) and FDA guidelines, encompassing accuracy, precision, linearity, quantification limit (QL), and detection limit (DL). The validation method was conducted through two approaches, namely UV region validation using PBS and the colorimetric method in the visible region (Vis). The validated approach is then employed for assessing in vitro release, ex vivo permeation, and in vivo pharmacokinetics. Results indicate superior MNX extraction recovery using methanol compared to acetonitrile. Method C (5mL methanol) is optimal, offering high recovery with minimal solvent usage. Precision assessments demonstrate %RSD values within MNX guidelines (≤15%), affirming accuracy and reproducibility. UV-Vis spectroscopy quantifies MNX integration into TDMN, using PVA-PVP, with concentrations aligning with ICH standards (95% to 105%). In conclusion, TDMN holds promise for enhancing MNX delivery, mitigating bioavailability and side effect challenges. The validated UV-Vis Spectrophotometer method effectively analyzes MNX in skin tissues, providing insights into AA treatment and establishing a robust analytical foundation for future studies.

Bioavailability enhancement of sildenafil citrate via hydrogel-forming microneedle strategy in combination with cyclodextrin complexation

Sildenafil citrate (SIL) as a first-line treatment for erectile dysfunction is currently reported to have poor solubility and bioavailability. Moreover, SIL undergoes first-pass metabolism when taken orally and its injection can lead to discomfort. In this study, we introduce a novel transdermal delivery system that integrates hydrogel-forming microneedles with the inclusion complex tablet reservoir. The hydrogel-forming microneedle was prepared from a mixture of polymers and crosslinkers through a crosslinking process. Importantly, the formulations showed high swelling capacity (>400 %) and exhibited adequate mechanical and penetration properties (needle height reduction < 10 %), penetrating up to five layers of Parafilm® M (assessed to reach the dermis layer). Furthermore, to improve the solubility of SIL in the reservoir, the SIL was pre-complexed with β-cyclodextrin. Molecular docking analysis showed that SIL was successfully encapsulated into the β-cyclodextrin cavity and was the most suitable conformation compared to other CD derivatives. Moreover, to maximize SIL delivery, sodium starch glycolate was also added to the reservoir formulation. As a proof of concept, in vivo studies demonstrated the effectiveness of this concept, resulting in a significant increase in AUC (area under the curve) compared to that obtained after administration of pure SIL oral suspension, inclusion complex, and Viagra® with relative bioavailability > 100 %. Therefore, the approach developed in this study could potentially increase the efficacy of SIL in treating erectile dysfunction by being non-invasive, safe, avoiding first-pass metabolism, and increasing drug bioavailability.

Development of pH-Sensitive Nanoparticle Incorporated into Dissolving Microarray Patch for Selective Delivery of Methotrexate

PURPOSE

Rheumatoid arthritis (RA) is a systemic autoimmune disease that attacks human joints. Methotrexate (MTX), as one the most effective medications to treat RA, has limitations when administered either orally or by injection. To overcome this limitation, we formulated MTX through a smart nanoparticle (SNP) combined with dissolving microarray patch (DMAP) to achieve selective-targeted delivery of RA.

METHODS

SNP was made using the combination of polyethylene glycol (PEG) and polycaprolactone (PCL) polymers, while DMAP was made using the combination of hyaluronic acid and polyvinylpyrrolidone K-30. SNP-DMAP was then evaluated for its mechanical and chemical characteristics, ex vivo permeation test, in vivo pharmacokinetic study, hemolysis, and hen's egg test-chorioallantoic membrane (HET-CAM) test.

RESULT

The results showed that the characteristics of the SNP-DMAP-MTX formulas meet the requirements for transdermal delivery, with the particle size of 189.09 ±12.30 nm and absorption efficiency of 65.40 ± 5.0%. The hemolysis and HET-CAM testing indicate that this formula was non-toxic and non-irritating. Ex vivo permeation shows a concentration of 51.50 ± 3.20 µg/mL of SNP-DMAP-MTX in PBS pH 5.0. The pharmacokinetic profile of SNP-DMAP-MTX showed selectivity and sustained release compared with oral and DMAP-MTX with values of t1/2 (4.88 ± 0 h), Tmax (8 ± 0 h), Cmax (0.50 ± 0.04 μg/mL), AUC (3.15 ± 0.54 μg/mL.h), and mean residence time (MRT) (9.13 ± 0 h).

CONCLUSION

The developed SNP-DMAP-MTX has been proven to deliver MTX transdermal and selectively at the RA site, potentially avoiding conventional MTX side effects and enhancing the effectiveness of RA therapy.

Recent progress of polymeric microneedle-assisted long-acting transdermal drug delivery

Microneedle (MN)-assisted drug delivery technology has gained increasing attention over the past two decades. Its advantages of self-management and being minimally invasive could allow this technology to be an alternative to hypodermic needles. MNs can penetrate the stratum corneum and deliver active ingredients to the body through the dermal tissue in a controlled and sustained release. Long-acting polymeric MNs can reduce administration frequency to improve patient compliance and therapeutic outcomes, especially in the management of chronic diseases. In addition, long-acting MNs could avoid gastrointestinal reactions and reduce side effects, which has potential value for clinical application. In this paper, advances in design strategies and applications of long-acting polymeric MNs are reviewed. We also discuss the challenges in scale manufacture and regulations of polymeric MN systems. These two aspects will accelerate the effective clinical translation of MN products.

Hydrogel: a new material for intravesical drug delivery after bladder cancer surgery

The standard treatment for non-muscle invasive bladder cancer (NMIBC) is transurethral resection of bladder tumor (TURBT). However, this procedure may miss small lesions or incompletely remove them, resulting in cancer recurrence or progression. As a result, intravesical instillation of chemotherapy or immunotherapy drugs is often used as an adjunctive treatment after TURBT to prevent cancer recurrence. In the traditional method, drugs are instilled into the patient's bladder through a urinary catheter under sterile conditions. However, this treatment exposes the bladder mucosa to the drug directly, leading to potential side effects like chemical cystitis. Furthermore, this treatment has several limitations, including a short drug retention period, susceptibility to urine dilution, low drug permeability, lack of targeted effect, and limited long-term clinical efficacy. Hydrogel, a polymer material with a high-water content, possesses solid elasticity and liquid fluidity, making it compatible with tissues and environmentally friendly. It exhibits great potential in various applications. One emerging use of hydrogels is in intravesical instillation. By employing hydrogels, drug dilution is minimized, and drug absorption, retention, and persistence in the bladder are enhanced due to the mucus-adhesive and flotation properties of hydrogel materials. Furthermore, hydrogels can improve drug permeability and offer targeting capabilities. This article critically examines the current applications and future prospects of hydrogels in the treatment of bladder cancer.

Topical Meloxicam Hydroxypropyl Guar Hydrogels Based on Low-Substituted Hydroxypropyl Cellulose Solid Dispersions

Meloxicam (MX) is a poorly water-soluble drug with severe gastrointestinal side effects. Topical hydrogel of hydroxypropyl guar (HPG) was formulated using a solid dispersion (SD) of MX with hydroxypropyl cellulose (LHPC) as an alternative to oral administration. The development of a solid dispersion with an adequate MX:LHPC ratio could increase the topical delivery of meloxicam. Solid dispersions showed high MX solubility values and were related to an increase in hydrophilicity. The drug/polymer and polymer/polymer interactions of solid dispersions within the HPG hydrogels were evaluated by SEM, DSC, FTIR, and viscosity studies. A porous structure was observed in the solid dispersion hydrogel MX:LHPC (1:2.5) and its higher viscosity was related to a high increase in hydrogen bonds among the -OH groups from LHPC and HPG with water molecules. In vitro drug release studies showed increases of 3.20 and 3.97-fold for hydrogels with MX:LHPC ratios of (1:1) and (1:2.5), respectively, at 2 h compared to hydrogel with pure MX. Finally, a fitting transition from zero to first-order model was observed for these hydrogels containing solid dispersions, while the n value of Korsmeyer-Peppas model indicated that release mechanism is governed by diffusion through an important relaxation of the polymer.

Application of Biomaterials in the Development of Hydrogel-Forming Microneedles Integrated with a Cyclodextrin Drug Reservoir for Improved Pharmacokinetic Profiles of Telmisartan

Telmisartan (TEL) is a promising antihypertensive agent among other angiotensin receptor blockers. However, its oral application is limited by its poor water solubility. This study presents the successful utilization of biomaterial-based hydrogel-forming microneedles integrated with a direct compressed tablet reservoir (HFMN-DCT) for the transdermal delivery of telmisartan in the treatment of hypertension. The combination of PVP, PVA, and tartaric acid was used in the HFMN formulation. A range of cross-linking temperatures and times were employed to optimize the characteristics of the HFMN. The HFMN exhibited excellent swelling capacity, mechanical strength, and insertion properties. Additionally, the poorly soluble characteristic of TEL was improved by the inclusion complex formulation with β-cyclodextrin (βCD). Phase solubility analysis showed an Ap-type diagram, indicating a higher-order complex between TEL and βCD, with respect to βCD. A ratio of TEL:βCD of 1:4 mM demonstrates the highest solubility enhancement of TEL. The inclusion complex formation was confirmed by FTIR, XRD, DSC, and molecular docking studies. A significantly higher release of TEL (up to 20-fold) from the inclusion complex was observed in the in vitro release study. Subsequently, a DCT reservoir was developed using various concentrations of sodium starch glycolate. Essentially, both the HFMN and DCT reservoir exhibit hemocompatibility and did not induce any skin irritation. The optimized combination of the HFMN-DCT reservoir showed an ex vivo permeation profile of 83.275 ± 2.405%. Notably, the proposed system showed superior pharmacokinetic profiles in the in vivo investigation using male Wistar rats. Overall, this study highlights the potential of HFMN-DCT reservoir systems as a versatile platform for transdermal drug delivery applications.

Solid Dispersion Incorporated into Dissolving Microneedles for Improved Antifungal Activity of Amphotericin B: In Vivo Study in a Fungal Keratitis Model

Fungal keratitis (FK) is a fungal infection of the cornea, which is part of the eye and causes corneal ulcers and an increased risk of permanent blindness, which is often found in Candida albicans species. Amphotericin B (AMB), which is a group of polyenes as the first-line treatment of FK, is effective in annihilating C. albicans. However, AMB preparations such as eye drops and ointments have major drawbacks, for instance, requiring more frequent administrations, loss of the drug by the drainage process, and rapid elimination in the precornea, which result in low bioavailability of the drug. An ocular dissolving microneedle containing the solid dispersion amphotericin B (DMN-SD-AMB) had been developed using a mixture of poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) polymers, while the solid dispersion AMB (SD-AMB) was contained in the needle as a drug. This study aims to determine the most optimal and safest DMN-SD-AMB formula for the treatment of FK in the eye as well as a solution to overcome the low bioavailability of AMB eye drops and ointment preparations. SD-AMB had been successfully developed, which was characterized by increased antifungal activity and drug release in vitro compared to other treatments. Furthermore, DMN-SD-AMB studies had also been successfully performed with the best formulation, which exhibited the best ex vivo corneal permeation profile and antifungal activity as well as being safe from eye irritation. In addition, an in vivo antifungal activity using a rabbit infection model shows that the number of fungal colonies was 0.98 ± 0.11 log10 CFU/mL (F3), 5.76 ± 0.32 log10 CFU/mL (AMB eye drops), 4.01 ± 0.28 log10 CFU/mL (AMB ointments), and 9.09 ± 0.65 log10 CFU/mL (control), which differed significantly (p < 0.05). All of these results evidence that DMN-SD-AMB is a new approach to developing intraocular preparations for the treatment of FK.

Development of chitosan-hyaluronic acid based hydrogel for local delivery of doxycycline hyclate in an ex vivo skin infection model

Doxycycline hyclate (DOXY) is a tetracycline derivative known as the broad-spectrum bacteriostatic drug. DOXY has been suggested as the first-line antibiotic for diabetic foot ulcers (DFU). Unfortunately, the long-term availability of DOXY in both oral and conventional topical dosage forms reduces its therapeutic effectiveness, which is closely linked to gastrointestinal side effects and acute pain during therapy, as well as uncontrolled DOXY release at the wound site. To address these shortcomings, we present for the first time a DOXY hydrogel system (DHs) built on crosslinks between carboxymethyl chitosan (CMC) and aldehyde hyaluronic acid (AHA). Three formulations of DHs were developed with different ratios of CMC and AHA, consisting of F1 (3:7, w/w), F2 (5:5, w/w), and F3 (7:3, w/w). Viscosity, rheology, gel strength, pH, swelling, gel fraction, wettability, stability, in vitro drug release, ex vivo antibacterial, and dermatokinetic studies were used to evaluate the DHs. According to the in vitro release study, up to 85% of DOXY was released from DHs via the Fickian diffusion mechanism in the Korsmeyer-Peppas model (n < 0.45), which provides controlled drug delivery. Because of its excellent physicochemical characteristics, F2 was chosen as the best DHs formulation in this study. Essentially, the optimum DHs formulation could greatly improve DOXY's ex vivo dermatokinetic profile while also providing excellent antibacterial activity. As a consequence, this study had promising outcome as a proof of concept for increasing the efficacy of DOXY in clinical therapy. Further extensive in vivo studies are required to evaluate the efficacy of this approach.

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.

Advances and Prospects for Hydrogel-Forming Microneedles in Transdermal Drug Delivery

Transdermal drug delivery (TDD) is one of the key approaches for treating diseases, avoiding first-pass effects, reducing systemic adverse drug reactions and improving patient compliance. Microneedling, iontophoresis, electroporation, laser ablation and ultrasound facilitation are often used to improve the efficiency of TDD. Among them, microneedling is a relatively simple and efficient means of drug delivery. Microneedles usually consist of micron-sized needles (50-900 μm in length) in arrays that can successfully penetrate the stratum corneum and deliver drugs in a minimally invasive manner below the stratum corneum without touching the blood vessels and nerves in the dermis, improving patient compliance. Hydrogel-forming microneedles (HFMs) are safe and non-toxic, with no residual matrix material, high drug loading capacity, and controlled drug release, and they are suitable for long-term, multiple drug delivery. This work reviewed the characteristics of the skin structure and TDD, introduced TDD strategies based on HFMs, and summarized the characteristics of HFM TDD systems and the evaluation methods of HFMs as well as the application of HFM drug delivery systems in disease treatment. The HFM drug delivery system has a wide scope for development, but the translation to clinical application still has more challenges.

Preparation and Evaluation of Auxiliary Permeable Microneedle Patch Composed of Polyvinyl Alcohol and Eudragit NM30D Aqueous Dispersion

Poor transdermal permeability limits the possibility of most drug delivery through the skin. Auxiliary permeable microneedles (AP-MNs) with a three-dimensional network structure can effectively break the skin stratum corneum barrier and assist in the transdermal delivery of active ingredients. Herein, we propose a simple method for preparing AP-MNs using polyvinyl alcohol and Eudragit NM30D for the first time. To optimize the formulation of microneedles, the characteristics of swelling properties, skin insertion, solution viscosity, and needle integrity were systematically examined. Additionally, the morphology, mechanical strength, formation mechanism, skin permeability, swelling performance, biocompatibility, and in vitro transdermal drug delivery of AP-MNs were evaluated. The results indicated that the microneedles exhibited excellent mechanical-strength and hydrogel-forming properties after swelling. Further, it proved that a continuous and unblockable network channel was created based on physical entanglement and encapsulation of two materials. The 24 h cumulative permeation of acidic and alkaline model drugs, azelaic acid and matrine, were 51.73 ± 2.61% and 54.02 ± 2.85%, respectively, significantly enhancing the transdermal permeability of the two drugs. In summary, the novel auxiliary permeable microneedles prepared through a simple blending route of two materials was a promising and valuable way to improve drug permeation efficiency.