Search Results (199)

Background: Effective strategies for delivering neuroprotective agents to the brain remain a major challenge due to the poor solubility, rapid metabolism, and low bioavailability of promising molecules, such as 7,8-dihydroxyflavone (7,8-DHF). This small-molecule TrkB receptor agonist exhibits significant antioxidant, neuroprotective properties, and additional effects on metabolic regulation, but its therapeutic potential is limited by unfavorable pharmacokinetic characteristics. Nanotechnology-based delivery systems are increasingly explored to improve drug stability, enhance bioavailability, and facilitate direct nose-to-brain transport following intranasal administration. In this study, lipid nanoparticles encapsulating 7,8-DHF were developed using a fish-oil-based lipid core enriched with ω-3 polyunsaturated fatty acids (DHA and EPA) and naturally derived excipients, including soybean lecithin and ε-polylysine. Methods: The formulation was optimized using a Design of Experiments (DoE) approach based on a 2³ full factorial design, evaluating drug concentration, lecithin concentration, and surfactant type (Pluronic^® F127 or Tween^® 80). The main formulation responses considered were particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency. Results: The optimized nanoparticles exhibited nanometric dimensions (<250 nm); spherical morphology, confirmed by TEM; low polydispersity (PDI < 0.3); and adequate encapsulation efficiency. Stability studies in simulated biological fluids indicated good physicochemical stability for up to 48 h, while interaction studies with mucin suggested a good interaction within the mucus environment. ROS scavenging capacity was confirmed through the DPPH chemical assay, and in vitro experiments on olfactory ensheathing cells, selected as a biologically relevant model for their anatomical localization along the olfactory pathway, showed reduced cytotoxicity of the encapsulated drug compared with the free form. Conclusions: Collectively, these results support the potential application of the developed nanoformulation in the intranasal delivery of 7,8-DHF. Full article

The cribriform plate (CP) functions as a dynamic neuroimmune interface through which olfactory nerve bundles exit the brain within a specialized perineural microenvironment (cpPME). While traditionally viewed as a passive structural barrier, emerging evidence positions the CP as a central hub for cerebrospinal fluid (CSF) drainage, glymphatic–lymphatic clearance, and antigen presentation. This review provides a comprehensive understanding of recent advances in cpPME research, highlighting the adaptive remodeling of the immune landscape in response to neuroinflammation and aging. We critically evaluate the translational gap between rodent models and human physiology, discussing the implications for neurodegenerative diagnostics, neuroinflammatory conditions, infectious diseases and “nose-to-brain” therapeutic delivery. By integrating anatomical, physiological, and immunological perspectives, we offer a comprehensive framework for understanding the CP’s role in CNS homeostasis and its potential as a transformative diagnostic and therapeutic target. Full article

Background/Objectives: Insomnia severely impairs quality of life. Oral melatonin (MEL) suffers from poor brain delivery. Intranasal administration bypasses the blood–brain barrier, but rapid mucociliary clearance shortens drug retention, and MEL poor water solubility limits its nasal dissolution. Traditional in situ gels have “gelation-first, spreading-second” defects, causing uneven distribution. Herein, we developed a two-step sequential ion-triggered in situ gel combined with MEL liposomes (MEL-Lips-Gel) to enhance solubility, achieve instant uniform coating, and prolong retention for efficient nose-to-brain delivery. Methods: MEL-Lips were dispersed in alginate (first component) and calcium gluconate served as the second component. After sequential spray, the two components mix and form an ion-crosslinked gel. Rheology, in vivo fluorescence imaging, in vitro release, open-field/sucrose preference tests, and H&E staining were performed. Results: MEL-Lips showed uniform size and good encapsulation. The sequential system achieved instant widespread spreading and rapid gelation, significantly prolonged nasal retention, enabled sustained brain delivery, and reversed insomnia-induced hyperactivity and anxiety-like behaviors more effectively than oral MEL, intranasal MEL solution, liposomes alone, or non-liposomal gel, with good nasal safety. Conclusions: This sequential ion-triggered liposome-in-gel strategy synergistically overcomes rapid clearance (via gel) and poor solubility (via liposomes), enhancing nose-to-brain delivery of melatonin and providing a promising platform for insomnia therapy. Full article

Background/Objectives: The oral administration of donepezil has been shown to have common side effects due to systemic drug delivery, with fluctuations in blood and brain donepezil concentrations. Therefore, we obtained nanostructured lipid carriers loaded with donepezil (donepezil–NLC) for nose-to-brain targeting. Methods: The obtained NLCs were characterized by measurements of particle size, the polydispersity index, zeta potential, encapsulation efficiency, atomic force microscopy, Differential Scanning Calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and in vitro release studies. Plasma and brain pharmacokinetic studies in Wistar rats were carried out to determine brain targeting. Results: Donepezil–NLC showed low polydispersity and nanometric size, high zeta potential, and high drug entrapment efficiency. Microscopy images showed spherical particles with regular surfaces. Thermal analysis, X-ray diffraction, and FTIR-ATR suggested the formation of an amorphous lipid matrix and the incorporation of donepezil molecularly dispersed within the lipid matrix. In vitro drug release studies demonstrated a biphasic drug release pattern with an initial burst followed by sustained release, with results better fitted to the Korsmeyer–Peppas model (n-value > 0.5). Following the nasal administration of donepezil–NLC, brain pharmacokinetic studies in Wistar rats demonstrated a significant improvement in bioavailability. Compared to the intravenous injection of donepezil, the AUC^0–ꝏ value was 10.5-fold higher. Drug targeting efficiency and direct transport percentage showed extremely higher values, suggesting nose-to-brain targeting after donepezil–NLC intranasal administration. Conclusions: Donepezil–NLC has proven to be an efficient drug delivery system for the nose to the brain, which may reduce systemic toxicity and improve Alzheimer’s therapy with low doses of donepezil and fewer adverse effects. Full article

Central nervous system (CNS) disorders represent a growing healthcare burden, and various drugs are developed for their treatment. However, the blood–brain barrier (BBB) prevents over 98% of therapeutics from reaching brain tissue. Intranasal delivery provides a promising alternative by exploiting olfactory and trigeminal nerve pathways to circumvent the BBB. This review surveys recent advances in nose-to-brain delivery technologies, from carrier design to evaluation methods. Polymeric and lipid-based nanocarriers show enhanced mucosal penetration and prolonged residence time, and microneedle platforms further enable controlled drug release with minimal discomfort. To evaluate these delivery strategies, sensor-integrated organ-on-chip models provide more physiologically relevant testing than static cultures. Although persistent challenges such as rapid mucociliary clearance and formulation stability remain, combining nanotechnology with microfluidic devices and computational modeling shows potential for developing patient-specific therapeutics. Full article

While the Blood–Brain Barrier (BBB) is essential for the protection and function of the Central Nervous System (CNS), it also represents a challenge for drug delivery in the treatment of CNS disorders due to its limited permeability and high expression of efflux transporters. Crossing the BBB becomes even more difficult when dealing with biomolecular therapeutics (e.g., monoclonal antibodies and Antisense Oligonucleotides) due to their hydrophilic nature and high molecular weight. Over the years, different strategies have been developed in order to maximize the ability of biopharmaceuticals to cross the BBB and be delivered to the CNS. Both non-invasive techniques, mainly consisting of developing innovative vectors or using non-conventional routes of administration (e.g., intranasal delivery), and invasive methods, such as intracerebroventricular/intrathecal administration, have been tested individually and in combination. Given the improvements achieved nowadays with both approaches, here, we plan to compare the advances in invasive techniques, such as those based on the use of device-assisted strategies, and the employment of the intranasal route of administration. We are also interested in reporting the applicability of both strategies in the treatment of aggressive forms of cancer, such as glioblastoma, as well as neurodegenerative diseases, in order to determine which technique can be considered a better choice in each specific case. Full article

Intranasal drug delivery represents a transformative “backdoor” to the brain, bypassing the blood–brain barrier (BBB) that bars 98% of small molecules and nearly all large biopharmaceuticals. By harnessing the unique anatomy of the olfactory and trigeminal nerves, therapeutics can travel directly from the nasal cavity to the central nervous system, achieving therapeutic concentrations without the systemic toxicity of traditional routes. Clinical and preclinical evidence highlight the efficacy of intranasal insulin (INI) in treating Alzheimer’s disease (AD) and delirium, with studies showing significant improvements in cognitive scores and reduced hospital stays (7.9 vs. 12.9 days; p = 0.014). Additionally, other peptides can be administered intranasally like oxytocin, neuropeptide Y, and novel metabolic modulators for neuroprotection and affective disorders (AD, autism, Down syndrome). Despite these promises, critical translational gaps remain, including anatomical differences between macrosmatic rodents and microsmatic humans, and significant sex-based dosing dimorphism. The ease of intranasal administration introduces profound bioethical dilemmas regarding neuroenhancement, authenticity, and informed consent in vulnerable populations. The current literature concludes that realizing the full potential of nose-to-brain (N2B) therapy requires a commitment to precision medicine, utilizing specialized delivery devices and objective biomarkers to ensure safe and equitable clinical application. Full article

Carbon nanotubes (CNTs) represent promising nanoplatforms for drug delivery due to their high surface area, tunable surface chemistry, and unique physicochemical properties. This study investigated the effect of chemical functionalization on the dispersion, drug loading, release behavior, aerosolization, and preliminary in vitro cytotoxicity of CNT-based drug delivery systems, with a view toward potential intranasal applications. Pristine CNTs and CNTs functionalized with hydroxyl (–OH) and carboxyl (–COOH) groups were loaded with methylene blue as a model therapeutic compound. The nanosystems were characterized using Raman spectroscopy, UV–Vis analysis, aerosol deposition measurements, electrical mapping by conductive atomic force microscopy (C-AFM), and MTT cytotoxicity assays. Functionalization significantly enhanced CNT dispersion stability and drug release control, with COOH–CNTs exhibiting the most sustained release profile and improved cytocompatibility, maintaining cell viability above XX% at concentrations up to YY µg/mL. Aerosolization tests demonstrated stable droplet formation compatible with nasal delivery devices. Overall, this work provides a proof-of-concept physicochemical and technological assessment of functionalized CNTs as potential carriers for intranasal drug delivery, laying the groundwork for future in vivo validation. Full article

This study aims to assess the rate and duration of rat brain retention after a single intranasal administration of indocyanine green (ICG) as an aqueous solution or encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles. Near-infrared fluorescence emission of ICG from the brain and visceral organs was measured at 1, 4, and 24 h, as well as at 1 and 2 weeks after administration. It was observed that both ICG formulations stained the olfactory bulbs and brainstem, the latter mainly in the basolateral region of the pons. Reduced staining was observed on day 7 after treatment, and the signal remains detectable on day 14. Additionally, while emission from ICG-labeled brains in water decreased after two weeks compared to day 7, in ICG-loaded nanoparticles, the emission was significantly higher on day 14. It is concluded that ICG is transported into the brain via both nose-to-brain delivery pathways—through and along olfactory or trigeminal nerves—and that ICG is a useful dye for in vivo studies due to its long-lasting emission and low toxicity. Furthermore, the suggested penetration of ICG-encapsulated PLGA nanoparticles via these transport mechanisms makes them a useful carrier for brain delivery of substances that are rapidly eliminated from circulation or do not cross the blood–brain barrier. Full article

The blood–brain barrier (BBB) presents the principal obstacle to drug delivery for Alzheimer’s disease (AD), severely restricting brain bioavailability and therapeutic efficacy. Taxifolin (TF) is a potent natural antioxidant with significant therapeutic potential. To enhance its efficacy in treating AD, we developed a brain-targeted delivery system based on a taxifolin-loaded thermosensitive hydrogel (TF-Gel). This platform integrates TF with a poly(N-isopropylacrylamide)-based thermosensitive hydrogel to enhance brain delivery, tissue penetration, and intracerebral retention via intranasal administration. TF-Gel exhibits excellent structural stability and functional performance, enabling efficient bypass of the BBB through the nasal–brain pathway. Furthermore, it regulates mitochondrial dysfunction, reverses abnormal levels of adenosine triphosphate (ATP), reactive oxygen species (ROS), and malondialdehyde (MDA) in neuronal mitochondria, repairs mitochondrial energy metabolism, restores mitochondrial dynamic balance, improves oxidative stress damage, and blocks cell apoptosis pathways. Collectively, these results highlight the strong potential of the TF-Gel nasal delivery system as a mitochondria-targeted therapeutic strategy for AD. Full article

Brain disorders remain a major global health challenge, highlighting the urgent need for innovative therapeutic strategies and efficient drug-delivery approaches. Among alternative routes, intranasal administration has garnered significant interest over recent decades, not only for its systemic delivery but also for its unique ability to bypass the bloodstream and the blood–brain barrier via the Nose-to-Brain (NtB) pathway. While numerous reviews have explored the opportunities and challenges of this route, industrial considerations—critical for successful clinical implementation and commercial development—remain insufficiently addressed. This review provides a comprehensive and critical assessment of the NtB pathway from a drug development and chemistry, manufacturing, and controls perspective, addressing key constraints in pre-clinical–clinical extrapolation, formulation design, device selection, dose feasibility, chronic safety, and regulatory requirements. We also discuss recent advances in neuronal targeting mechanisms, also with a focus on the role of trigeminal nerves. Dodecyl creatine ester (DCE), a highly unstable in plasma creatine prodrug developed by Ceres Brain Therapeutics, is presented as an illustrative case study. Delivered as a nasal spray, DCE enables direct neuronal delivery, exemplifying the potential of the NtB pathway for disorders characterized by neuronal energy deficiency, including creatine transporter deficiency and mitochondrial dysfunction. Overall, the NtB pathway—or, more precisely, the “Nose-to-Neurons” pathway—offers distinct advantages for unstable molecules and metabolic supplementation, particularly in neuron-centric diseases. Its successful implementation will depend on rational molecule design, optimized nasal formulations, appropriate devices, and early integration of industrial constraints to ensure feasibility, scalability, and safety for long-term treatment. Full article

Diroximel fumarate (DRF) is an orally administered prodrug used in multiple sclerosis (MS) treatment. Although it exhibits better gastrointestinal (GI) tolerability than its analogues, many patients still discontinue therapy due to frequent GI adverse events. To overcome these limitations, alternative drug delivery systems that bypass the GI tract are needed. Direct nose-to-brain delivery represents a promising approach to circumvent the blood–brain barrier and target the central nervous system; however, limited nasal mucosal absorption and the small volume of the nasal cavity pose significant challenges. Solid lipid nanoparticles (SLNs) can potentially overcome these obstacles by enhancing drug bioavailability and protecting against enzymatic degradation. This research aimed to develop an innovative intranasal nanoformulation of DRF to improve brain targeting and patient compliance. DRF-loaded SLNs were prepared using a solvent-diffusion technique with stearic acid as the lipid phase and Poloxamer 188 as the surfactant. The obtained nanoparticles displayed favorable technological characteristics, with a mean diameter of 210 nm, a polydispersity index of 0.17, and a zeta potential of −36 mV, suggesting good long-term stability. Interactions between SLNs and biomembrane models (MLV) were also studied to elucidate their cellular uptake mechanism. Future work will focus on evaluating the in vivo efficacy of this novel nanoformulation. Full article

Objective: To develop a stable nanoemulsion loaded with Magnoliae Flos essential oil (MEO-NE) and evaluated its potential as an enhancer for nose-to-brain delivery in both solution and gel formulations. Methods: The MEO-NE was prepared using a low-energy emulsification method, with the formulation optimized via single-factor experiments and Box–Behnken design-response surface methodology. The optimized MEO-NE was characterized for particle size, PDI, morphology, and nasal mucosal irritation. Ex vivo histological imaging in rats was performed using hydrophilic sulfo-cyanine7 carboxylic acid and lipophilic coumarin 6 as fluorescent probes to assess distribution and retention in the trigeminal nerve and brain tissues. Results: The optimized MEO-NE exhibited a small particle size (27.96 ± 0.94 nm), low PDI (0.089 ± 0.013), spherical morphology, a stable O/W structure, and no irritation to the nasal mucosa. Ex vivo imaging revealed that MEO-NE significantly enhanced the distribution and retention of both hydrophilic and lipophilic probes in the trigeminal nerve and brain tissues. Moreover, the gel formulation of MEO-NE demonstrated superior brain-targeting efficiency over the solution within 6 h. Conclusions: MEO-NE served as an effective enhancer for nose-to-brain delivery, improving brain uptake of both hydrophilic and lipophilic drugs, and provided an experimental basis for utilizing herbal essential oils in CNS-targeted delivery systems. Full article

Background/Objectives: Cachexia is a syndrome characterized by the progressive loss of muscle mass, leading to high morbidity and mortality. Ghrelin (Ghrl) exhibits orexigenic, anabolic, and anti-inflammatory properties with therapeutic potential. However, its low bioavailability limits the efficacy of systemic treatments. This study aimed to develop chitosan-coated liposomes containing Ghrl (CH-Lip + Ghrl) for intranasal administration, allowing quantification of Ghrl brain bioavailability using a system optimized for a labile neuropeptide. Methods: The formulation was prepared using thin-film hydration, followed by extrusion and chitosan coating. It was characterized based on morphology, size, zeta potential, stability, encapsulation efficiency, and cell viability. Permeation and mucoadhesion were evaluated ex vivo using porcine nasal mucosa, and cerebral bioavailability was assessed in Wistar rats. Results: CH-Lip + Ghrl had an average of 152.4 ± 0.2 nm (evaluated by DLS), a polydispersity index of 0.159 ± 0.018, a zeta potential of +60.8 ± 6.6 mV, and an encapsulation efficiency of 53.2 ± 0.8%, maintaining stability for 180 days. At 1% (v/v) in culture medium, the formulation retained 73.2 ± 8.4% of the viability in nasal epithelial cells and 81.9 ± 4.8% in neuroblastoma cells. Chitosan coating increased ex vivo mucoadhesion 1.7-fold and permeation 1.3-fold. In vivo, 25 min after intranasal administration, CH-Lip + Ghrl delivered 48.2 ± 8.8% of the dose to the brain, whereas free Ghrl was undetectable. Conclusions: The intranasal administration of CH-Lip + Ghrl enhances cerebral bioavailability of Ghrl. This study integrates a chemically labile neuropeptide with chitosan-coated liposomes for direct brain delivery, representing an innovative platform for future translational studies. Full article

Ischemic stroke remains a major cause of mortality and long-term disability, yet current therapeutic strategies are largely limited to reperfusion approaches such as intravenous thrombolysis and thrombectomy, which are constrained by narrow treatment windows and the risk of complications. Moreover, the blood–brain barrier (BBB) severely restricts drug penetration into the injured brain, limiting the translation of promising neuroprotective agents into clinical success. Intranasal (IN) delivery has emerged as a compelling alternative route that bypasses the BBB and enables rapid access to the central nervous system through olfactory, trigeminal, and perivascular pathways. This narrative review highlights recent advances in preclinical research on IN therapeutics for ischemic stroke, ranging from small molecules and biologics to nucleic acids and cell-based therapies. Particular emphasis is placed on the application of nanotechnology, including extracellular vesicles, liposomes, and inorganic nanoparticles, which enhance drug stability, targeting, and bioavailability. Studies demonstrate that IN delivery of growth factors, cytokines, and engineered stem cells can promote neurogenesis, angiogenesis, white matter repair, and functional recovery, while nanocarriers further expand the therapeutic potential. Overall, intranasal delivery represents a promising and non-invasive strategy to overcome the limitations of conventional stroke therapies, offering new avenues for neuroprotection and regeneration that warrant further investigation toward clinical translation. Full article