Pharmacokinetic Evaluation of a Novel Donepezil-Loaded Dissolving Microneedle Patch in Rats

Development of Minodronic Acid-Loaded Dissolving Microneedles for Enhanced Osteoporosis Therapy: Influence of Drug Loading on the Bioavailability of Minodronic Acid

Osteoporosis is a metabolic bone disorder with impaired bone microstructure and increased bone fractures, seriously affecting the quality of life of patients. Among various bisphosphonates prescribed for managing osteoporosis, minodronic acid (MA) is the most potent inhibitor of bone context resorption. However, oral MA tablet is the only commercialized dosage form that has extremely low bioavailability, severe adverse reactions, and poor patient compliance. To tackle these issues, we developed MA-loaded dissolving microneedles (MA-MNs) with significantly improved bioavailability for osteoporosis therapy. We investigated the influence of drug loading on the physicochemical properties, transdermal permeation behavior, and pharmacokinetics of MA-MNs. The drug loading of MA-MNs exerted almost no effect on their morphology, mechanical property, and skin insertion ability, but it compromised the transdermal permeability and bioavailability of MA-MNs. Compared with oral MA, MA-MNs with the lowest drug loading (224.9 μg/patch) showed a 9-fold and 25.8-fold increase in peak concentration and bioavailability, respectively. This may be ascribed to the reason that the increased drug loading can generate higher burst release, higher drug residual rate, and drug supersaturation effect in skin tissues, eventually limiting drug absorption into the systemic circulation. Moreover, MA-MNs prolonged the half-life of MA and provided more steady plasma drug concentrations than intravenously injected MA, which helps to reduce dosing frequency and side effects. Therefore, dissolving MNs with optimized drug loading provides a promising alternative for bisphosphonate drug delivery.

Fabrication of Hybrid Coated Microneedles with Donepezil Utilizing Digital Light Processing and Semisolid Extrusion Printing for the Management of Alzheimer's Disease

Microneedle (MN) patches are gaining increasing attention as a cost-effective technology for delivering drugs directly into the skin. In the present study, two different 3D printing processes were utilized to produce coated MNs, namely, digital light processing (DLP) and semisolid extrusion (SSE). Donepezil (DN), a cholinesterase inhibitor administered for the treatment of Alzheimer's disease, was incorporated into the coating material. Physiochemical characterization of the coated MNs confirmed the successful incorporation of donepezil as well as the stability and suitability of the materials for transdermal delivery. Optical microscopy and SEM studies validated the uniform weight distribution and precise dimensions of the MN arrays, while mechanical testing ensured the MNs' robustness, ensuring efficient skin penetration. In vitro studies were conducted to evaluate the produced transdermal patches, indicating their potential use in clinical treatment. Permeation studies revealed a significant increase in DN permeation compared to plain coating material, affirming the effectiveness of the MNs in enhancing transdermal drug delivery. Confocal laser scanning microscopy (CLSM) elucidated the distribution of the API, within skin layers, demonstrating sustained drug release and transcellular transport pathways. Finally, cell studies were also conducted on NIH3T3 fibroblasts to evaluate the biocompatibility and safety of the printed objects for transdermal applications.

Translation from Preclinical Research to Clinical Trials: Transdermal Drug Delivery for Neurodegenerative and Mental Disorders

Neurodegenerative diseases (NDs), particularly dementia, provide significant problems to worldwide healthcare systems. The development of therapeutic materials for various diseases has a severe challenge in the form of the blood-brain barrier (BBB). Transdermal treatment has recently garnered widespread favor as an alternative method of delivering active chemicals to the brain. This approach has several advantages, including low invasiveness, self-administration, avoidance of first-pass metabolism, preservation of steady plasma concentrations, regulated release, safety, efficacy, and better patient compliance. Topics include the transdermal method for therapeutic NDs, their classification, and the mechanisms that allow the medicine to enter the bloodstream through the skin. The paper also discusses the obstacles and potential outcomes of transdermal therapy, emphasizing the benefits and drawbacks of different approaches.

Tiny titans- unravelling the potential of polysaccharides and proteins based dissolving microneedles in drug delivery and theranostics: A comprehensive review

In recent years, microneedles (MNs) have emerged as a promising alternative to traditional drug delivery systems in transdermal drug delivery. The use of MNs has demonstrated significant potential in improving patient acceptance and convenience while avoiding the invasiveness of traditional injections. Dissolving, solid, hollow, coated, and hydrogel microneedles are among the various types studied for drug delivery. Dissolving microneedles (DMNs), in particular, have gained attention for their safety, painlessness, patient convenience, and high delivery efficiency. This comprehensive review primarily focuses on different types of microneedles, fabrication methods, and materials used in fabrication of DMNs such as hyaluronic acid, chitosan, alginate, gelatin, collagen, silk fibroin, albumin, cellulose and starch, to list a few. The review also provides an exhaustive discussion on the applications of DMNs, including the delivery of vaccines, cosmetic agents, contraceptives, hormone and genes, and other therapeutic applications like for treating cancer, skin diseases, and diabetes, among others, are covered in this review. Additionally, this review highlights some of the DMN systems that are presently undergoing clinical trials. Finally, the review discusses current advances and trends in DMNs, as well as future prospective directions for this ground-breaking technology in drug delivery.

Smart microneedle patches for wound healing and management

The number of patients with non-healing wounds is generally increasing globally, placing a huge social and economic burden on every country. The complexity of the wound-healing process remains a major health challenge despite the numerous studies that have been reported on conventional wound dressings. Therefore, a therapeutic system that combines diagnostic and therapeutic modalities is essential to monitor wound-related biomarkers and facilitate wound healing in real time. Microneedles, as a multifunctional platform, are promising for transdermal diagnostics and drug delivery. Their advantages are mainly reflected in painless transdermal drug delivery, good biocompatibility, and ease of self-administration. In this work, we review recent advances in the use of microneedle patches for wound healing and monitoring. The paper first provides a brief overview of the skin structure and the wound healing process, and then discusses the current state of research and prospects for the development of wound-related biomarkers and their real-time monitoring based on microneedle sensors. It summarizes the current state of research based on the unique design of microneedle patches, including biomimetic, conductive, and environmentally responsive, to achieve wound healing. It further summarizes the prospects for the application of different microneedle-based drug delivery modalities and drug delivery substances for wound healing, due to their superior transdermal drug delivery advantages. It concludes with challenges and expectations for the use of smart microneedle patches for wound healing and management.

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.

Drug Delivery Systems as a Strategy to Improve the Efficacy of FDA-Approved Alzheimer's Drugs

Alzheimer's disease (AD) is the most common form of dementia, with a high impact worldwide, accounting for more than 46 million cases. The continuous increase of AD demands the fast development of preventive and curative therapeutic strategies that are truly effective. The drugs approved for AD treatment are classified into acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists. The therapeutic effectiveness of those drugs is hindered by their restricted access to the brain due to the blood-brain barrier, low bioavailability, and poor pharmacokinetic properties. In addition, the drugs are reported to have undesirable side effects. Several drug delivery systems (DDSs) have been widely exploited to address these issues. DDSs serve as drug carriers, combining the ability to deliver drugs locally and in a targeted manner with the ability to release them in a controlled and sustained manner. As a result, the pharmacological therapeutic effectiveness is raised, while the unwanted side effects induced by the unspecific distribution decrease. This article reviews the recently developed DDSs to increase the efficacy of Food and Drug Administration-approved AD drugs.

Celecoxib nanocrystal-loaded dissolving microneedles with highly efficient for osteoarthritis treatment

Osteoarthritis (OA) is a prevalent degenerative disease that has a significant impact on patients' lives. Celecoxib (CXB) is now primarily used to treat OA with oral dosing. CXB's limited water solubility, on the other hand, restricts its therapeutic application. We developed a delivery system of dissolving microneedles (DMNs) loaded with CXB-nanocrystals (CXB-NCs) for the treatment of OA. Oral administration's inefficiency and injectable administration's poor compliance might be solved using DMNs. Furthermore, carrier-free NCs may dramatically increase the dissolution of drugs with poorly water-solubility, as well as the drug load of DMNs. Antisolvent precipitation was used to make CXB-NCs. CXB-NC@DMNs were prepared by mixing CXB-NCs with hyaluronic acid (HA) that had high mechanical qualities and could permeate the skin efficiently in vitro. The therapeutic effect of oral CXB-NCs was substantially better than that of the same dose of oral CXB in an in vivo pharmacodynamic trial, demonstrating that the preparation of CXB into NCs might greatly increase CXB bioavailability. Furthermore, we discovered that DMNs loaded with low-dose CXB-NCs had similar or even better efficacy than the oral CXB-NCs group. The findings suggested that CXB-NC@DMNs may be a very efficient and promising drug delivery strategy in the treatment of OA.