Evaluation of intranasal delivery route of drug administration for brain targeting

Targeting capabilities of engineered extracellular vesicles for the treatment of neurological diseases

Recent advances in research on extracellular vesicles have significantly enhanced their potential as therapeutic agents for neurological diseases. Owing to their therapeutic properties and ability to cross the blood-brain barrier, extracellular vesicles are recognized as promising drug delivery vehicles for various neurological conditions, including ischemic stroke, traumatic brain injury, neurodegenerative diseases, glioma, and psychosis. However, the clinical application of natural extracellular vesicles is hindered by their limited targeting ability and short clearance from the body. To address these limitations, multiple engineering strategies have been developed to enhance the targeting capabilities of extracellular vesicles, thereby enabling the delivery of therapeutic contents to specific tissues or cells. Therefore, this review aims to highlight the latest advancements in natural and targeting-engineered extracellular vesicles, exploring their applications in treating traumatic brain injury, ischemic stroke, Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, glioma, and psychosis. Additionally, we summarized recent clinical trials involving extracellular vesicles and discussed the challenges and future prospects of using targeting-engineered extracellular vesicles for drug delivery in treating neurological diseases. This review offers new insights for developing highly targeted therapies in this field.

A nasally administrated reactive oxygen species-responsive carrier-free gene delivery nanosystem for Alzheimer's disease combination therapy

Combination therapies targeting multiple pathways are needed in order to improve treatment outcomes in Alzheimer's disease (AD) due to its complex pathogenesis. Amyloid-β and microglia-mediated neuroinflammation significantly contribute to AD pathogenesis. Amyloid-β-related nucleic acid drugs have demonstrated considerable potential in AD treatment; however, their clinical translation is limited by complex synthesis processes and carrier toxicity. Herein, an intranasally administrated, reactive oxygen species (ROS)-responsive, carrier-free gene delivery nanosystem (FTBR-NAC) was constructed for re-polarizing microglia and decreasing amyloid-β expression. In this nanosystem, fingolimod was conjugated with biguanide via an ROS-responsive linker to form the carrier for β-secretase 1 siRNA (siBACE1) to form FTBR nanoparticles. The electropositivity of FTBR and mucolytic activity of N-acetylcysteine (NAC) together enhanced the brain entry of FTBR. Upon reaching the brain, FTBR responded to the elevated ROS at the pathological site, releasing siBACE1 and fingolimod. Administration of FTBR-NAC improved cognitive function in AD mice, demonstrating the high therapeutic efficacy of this relatively simple nanosystem.

Chronic, combinatorial targeting of NMDARs and 5-HT4Rs exerts extended behavioral effects against stress-induced perseverative behavior and hyponeophagia

Serotonin (5-HT) receptors and N-methyl-D-aspartate receptors (NMDARs) have both been implicated in stress-induced psychiatric disorders. However, there is a paucity of studies evaluating the effectiveness of novel combinatorial pharmacological treatments to treat stress-related disorders. Here, we evaluated whether administration of combinatorial (R,S)-ketamine, an NMDAR antagonist and Food and Drug Administration (FDA)-approved anesthetic, and prucalopride, a 5-HT type IV receptor (5-HT4R) agonist and FDA-approved drug for chronic idiopathic constipation (CIC), would have additional effects when administered after stress. A single injection of saline (Sal), (R,S)-ketamine (K), prucalopride (P), or a combined dose of (R,S)-ketamine and prucalopride (K + P) was administered for 1x, 2x, or 7x per week for 2 weeks after either contextual fear conditioning (CFC), learned helplessness (LH), stress enhanced fear learning (SEFL), or chronic corticosterone (CORT) stress in both sexes. Drug efficacy was assayed using assays to measure fear, behavioral despair, perseverative, and/or hyponeophagia. Combinatorial drug administration was also tested using intranasal delivery. We found that combinatorial K + P exerted additional effects, compared to either drug alone, in reducing a variety of stress-induced behaviors in both sexes. Moreover, intranasal dosing was also effective. Our results indicate that chronic administration of K + P has extended benefits for combating stress-induced pathophysiology. Our findings provide strong evidence that future clinical studies using this chronic treatment strategy may prove advantageous in decreasing a broad range of stress-induced psychiatric disorders.

Chitosan Nanoparticles: Approaches to Preparation, Key Properties, Drug Delivery Systems, and Developments in Therapeutic Efficacy

The integration of nanotechnology into drug delivery systems holds great promise for enhancing pharmaceutical effectiveness. This approach enables precise targeting, controlled release, improved patient compliance, reduced side effects, and increased bioavailability. Nanoparticles are vital for transporting biomolecules-such as proteins, enzymes, genes, and vaccines-through various administration routes, including oral, intranasal, vaginal, buccal, and pulmonary. Among biodegradable polymers, chitosan, a linear polysaccharide derived from chitin, stands out due to its biocompatibility, safety, biodegradability, mucoadhesive properties, and ability to enhance permeation. Its cationic nature supports strong molecular interactions and provides antimicrobial, anti-inflammatory, and hemostatic benefits. However, its solubility, influenced by pH and ionic sensitivity, poses challenges requiring effective solutions. This review explores chitosan, its modified derivatives and chitosan nanoparticles mainly, focusing on nanoparticles physicochemical properties, drug release mechanisms, preparation methods, and factors affecting their mean hydrodynamic diameter (particle size). It highlights their application in drug delivery systems and disease treatments across various routes. Key considerations include drug loading capacity, zeta potential, and stability, alongside the impact of molecular weight, degree of deacetylation, and drug solubility on nanoparticle properties. Recent advancements and studies underscore chitosan's potential, emphasizing its modified derivatives'versatility in improving therapeutic outcomes.

Potent therapeutic efficacy of intranasally deliverable paclitaxel modified with pH-sensitive and PEGylated polymeric micelle against glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive and common type of brain tumor. Conventional therapies for GBM, such as surgery or radiotherapy, have shown inadequate therapeutic effect. Similarly, a large fraction of chemotherapeutics are ineffective against GBM due to the blood-brain barrier (BBB) preventing effective delivery of these drugs to the brain. To overcome these obstacles, an intranasally administrable and multifunctional drug-loaded polymeric micelle composed of a pH-sensitive PPCBA-PEI-Arg (PPA) polymer conjugated with PEGylated paclitaxel (PEG-PTX; PPP) was synthesized to treat GBM. PPP was more soluble in an aqueous solution than parental PTX and was more effectively internalized into the GBM cells. Further, PPP elicited a more potent cancer cell killing effect than PTX under physiological pH condition, which was further augmented under the mildly acidic condition that emulated the tumor microenvironment. Intranasal administration of PPP into orthotopic GBM tumor xenograft-bearing mice led to more efficient delivery of the drug to the brain tissues compared to parental PTX delivered via intranasal or intravenous route, thus resulting in superior inhibition of GBM growth. Collectively, these findings demonstrated that intranasal delivery of PTX via pH-sensitive and PEGylated polymeric micelles can be an effective approach for the treatment of aggressive GBM.

The nasal route for nose-to-brain drug delivery: advanced nasal formulations for CNS disorders

INTRODUCTION

The nasal route offers a feasible alternative to oral and/or parenteral administration, providing a noninvasive route to achieve nose-to-brain drug delivery involving the olfactory and trigeminal nerves, and facilitating local or systemic drug action. Conventional liquid nasal dosage forms have not managed to bridge the gaps of precise dosing and targeted central nervous system (CNS) delivery, while more sophisticated formulation approaches are being explored for brain targeting, aiming to enhance bioavailability and therapeutic efficacy.

AREAS COVERED

This review focuses on preclinical and clinical evaluation of microemulsions, in-situ gels, nasal powders, and nanocarrier-based formulations. Key pharmacokinetic and pharmacodynamic findings are discussed to evaluate their potential and limitations in improving drug bioavailability and CNS targeting. The existing regulatory framework for approval of products for nose-to-brain drug delivery is also addressed and relative hurdles are discussed.

EXPERT OPINION

While nasal drug delivery holds great promise for CNS therapeutics, key challenges remain, including formulation stability, mucosal permeability, patient adherence. Future research should prioritize improving targeting efficiency, overcoming mucociliary clearance, developing user-friendly pharmaceutical products. Personalized medicine and smart delivery systems could further enhance drug targeting and minimize side effects. Continued research and regulatory advancements are essential to fully realize nasal delivery's perspective in CNS therapeutics.

Intranasal delivery of kaempferol via magnesomes for brain seizure treatment: Design, characterization, and biodistribution studies

The current study aims to develop phospholipid magnesomes retaining the inherent neuroprotective activities of kaempferol as a proposed treatment approach for epilepsy. Magnesomes were prepared using varied amounts of phospholipid, magnesium sulfate and poloxamer 188, and evaluated on in-vitro and in-vivo levels. The prepared vesicles possessed nanosizes (112-625 nm), negative charges (-16 to -20 mV), and entrapment efficiency (80-96 %) with negligible changes in their colloidal properties after 3 months' storage. Magnesomes showed sustained release of kaempferol as well as superior permeability relative to drug solution. Radiolabeling of kaempferol with iodine-131 was successfully performed using electrophilic substitution. The superior brain uptake of intranasally delivered 131I-kaempferol-magnesomes containing 3.13 µg/20µl of kaempferol compared to intravenous and intranasal solutions was demonstrated employing biodistribution and pharmacokinetic tests conducted using Swiss Albino male mice. Brain to blood ratio of the intranasally administered kaempferol was significantly higher compared to intravenous injection showing uptake of 9.9 ± 0.3 % injected dose per gram organ at the first 5 min ensuring a rapid onset of action. The drug targeting efficiency and nose to brain direct transport percentages of 131I- kaempferol-magnesomes were 215.0 and 87.0 %, respectively with relative bioavailability of 810.24 ± 119.1 %. Accordingly, intranasal kaempferol-magnesomes showed effectiveness in brain targeting and could be beneficial for managing epileptic seizures.

Intranasal administration of tissue inhibitor of metalloproteinase 1 extracted from stem cells from human exfoliated deciduous teeth-conditioned medium improves neurological outcomes and alpha-synuclein elimination in Parkinson's disease mice

Background/purpose

Parkinson's disease (PD) remains a challenging neurodegenerative disorder, requiring the exploration of innovative therapeutic strategies. This study assessed the neuroprotective effects of stem cells from human exfoliated deciduous teeth-conditioned medium (SHED-CM) in a rotenone-induced mouse model of PD.

Materials and methods

The SHED-CM, fractionated and purified via Fast Protein Liquid Chromatography (FPLC) into "yPD01", was administered intranasally to evaluate its impact on motor deficits, olfactory functions, and protein expressions in affected brain regions.

Results

Upon intranasal delivery, yPD01 produced significant improvements to motor deficits and restoration of protein expressions associated with PD pathology, particularly in the olfactory bulb and substantial nigra. Intriguingly, the intranasal route exhibited efficacy akin to intravenous administration, highlighting its potential as a minimally invasive yet equally effective therapeutic approach. Further investigation indicated key components within yPD01, denoted as peaks P1 and P5, showcasing pivotal therapeutic effects. These components were linked to the interruption of alpha-synuclein aggregation and its clearance within specific brain cells affected by PD.

Conclusion

Intranasally administered yPD01 shows neuroprotective potential for mitigating neurodegenerative symptoms, particularly in PD. The results provide valuable insights into potential mechanisms underlying the neuroprotective effects of SHED-CM and their implications for future therapeutic interventions in PD and related conditions.

Post-Stroke Recovery: A Review of Hydrogel-Based Phytochemical Delivery Systems

Stroke remains a leading cause of disability worldwide, underscoring the urgent need for novel and innovative therapeutic strategies to enhance neuroprotection, support regeneration, and improve functional recovery. Previous research has shown that phytochemicals such as curcumin, tannic acid, gallic acid, ginsenosides, resveratrol, and isorhamnetin display extensive neuroprotective properties, including antioxidant, anti-inflammatory, and anti-apoptotic effects. These natural compounds could also promote neurogenesis, angiogenesis, and the preservation of the blood-brain barrier. Despite their promising bioactivities, clinical application is often limited by poor solubility, bioavailability, and suboptimal pharmacokinetics. Hydrogels offer a promising solution by encapsulating and controlling the gradual release of these phytochemicals directly at the site of injury. Recent advancements in hydrogel formulations, constructed from biopolymers and functionalized using nanotechnological approaches, could significantly improve the solubility, stability, and targeted delivery of phytochemicals. Controlled release profiles from pH-sensitive and environment-responsive hydrogels could ensure that the compounds' therapeutic effects are optimally timed with individual and critical stages of post-stroke repair. Moreover, hydrogel scaffolds with tailored material properties and biocompatibility can create a favorable microenvironment, reducing secondary inflammation, enhancing tissue regeneration, and potentially improving functional and cognitive outcomes following stroke. This review explores the potential of integrating phytochemicals within hydrogel-based delivery systems specifically designed for post-stroke recovery. The design and synthesis of biocompatible, biodegradable hydrogels functionalized especially with phytochemicals and their applications are also discussed. Lastly, we emphasize the need for additional robust and translatable preclinical studies.

How does oxytocin modulate human behavior?

While the highly evolutionarily conserved hypothalamic neuropeptide, oxytocin (OT) can influence cognitive, emotional and social functions, and may have therapeutic potential in disorders with social dysfunction, it is still unclear how it acts. Here, we review the most established findings in both animal model and human studies regarding stimuli which evoke OT release, its primary functional effects and the mechanisms whereby exogenous administration influences brain and behavior. We also review progress on whether OT administration can improve social symptoms in autism spectrum disorder and schizophrenia and consider possible impediments to translational success. Importantly, we emphasize that OT acting via its extensive central or peripheral receptors primarily influences behavior indirectly through neuromodulatory interactions with classical transmitters and other peptides which themselves can independently influence behavior. We also emphasize that exogenous administration studies increasingly demonstrate peripheral effects of OT may be of greater importance than originally thought, especially involving the vagus. Overall, we propose a hierarchical model whereby OT's neuromodulatory actions influence behavior across interconnected functional domains and ultimately help to promote survival, security and sociability. Initially, OT potently facilitates attention to salient social and other important stimuli and additionally modulates cognitive, emotional and reward processing in a person- and context-dependent manner to promote interpersonal social understanding, attraction and bonds on the one hand and social group cohesion through increased conformity, altruistic punishment and moral emotions on the other. OT also increases co-operation and protection across both social domains. We hope this review and model will promote further research and help aid future translation success.

In Situ Recovery of Serotonin Synthesis by a Tryptophan Hydroxylase-Like Nanozyme for the Treatment of Depression

Depression is one of the most common mental disorders. The inactivation of tryptophan hydroxylase and the resulting serotonin decrease are the key factors in depression pathology. Herein, we report for the first time that Fe3O4 nanoparticles exhibit tryptophan hydroxylase-like activity and successfully verify their ability to restore serotonin synthesis in the brain for the treatment of depression. To achieve better biocompatibility and brain delivery, the Fe3O4 nanoparticles were functionalized with chitosan (CS) (Fe3O4@CS), enabling their delivery from the nose to the brain. Fe3O4@CS catalyzes the transformation of tryptophan into 5-hydroxytryptophan with the participation of high levels of endogenous ascorbic acid and hydrogen peroxide in stressed neurons, thus compensating for the deactivated tryptophan hydroxylase in the brain. In vivo Fe3O4@CS treatment results in the recovery of 5-hydroxytryptophan and serotonin levels and improvement of neuronal signal transduction ability in a depression mouse model, thus ameliorating depressive-like behaviors. The presented strategy of restoring serotonin synthesis in situ based on a tryptophan hydroxylase-like nanozyme provides a more accurate and efficient approach for the treatment of depression.

Extracellular Vesicles for Disease Treatment

Traditional drug therapies suffer from problems such as easy drug degradation, side effects, and treatment resistance. Traditional disease diagnosis also suffers from high error rates and late diagnosis. Extracellular vesicles (EVs) are nanoscale spherical lipid bilayer vesicles secreted by cells that carry various biologically active components and are integral to intercellular communication. EVs can be found in different body fluids and may reflect the state of the parental cells, making them ideal noninvasive biomarkers for disease-specific diagnosis. The multifaceted characteristics of EVs render them optimal candidates for drug delivery vehicles, with evidence suggesting their efficacy in the treatment of various ailments. However, poor stability and easy degradation of natural EVs have affected their applications. To solve the problems of poor stability and easy degradation of natural EVs, they can be engineered and modified to obtain more stable and multifunctional EVs. In this study, we review the shortcomings of traditional drug delivery methods and describe how to modify EVs to form engineered EVs to improve their utilization. An innovative stimulus-responsive drug delivery system for EVs has also been proposed. We also summarize the current applications and research status of EVs in the diagnosis and treatment of different systemic diseases, and look forward to future research directions, providing research ideas for scholars.

Intranasal delivery of extracellular vesicles: A promising new approach for treating neurological and respiratory disorders

BACKGROUND

Extracellular vesicles (EVs) are membrane vesicles secreted by all types of cells, including bacteria, animals, and plants. These vesicles contain proteins, nucleic acids, and lipids from their parent cells and can transfer these components between cells. EVs have attracted attention for their potential use in diagnosis and therapy due to their natural properties, such as low immunogenicity, high biocompatibility, and ability to cross the blood-brain barrier. They can also be engineered to carry therapeutic molecules. EVs can be delivered via various routes. The intranasal route is particularly advantageous for delivering them to the central nervous system, making it a promising approach for treating neurological disorders.

SCOPE OF REVIEW

This review delves into the promising potential of intranasally administered EVs-based therapies for various medical conditions, with a particular focus on those affecting the brain and central nervous system. Additionally, the potential use of these therapies for pulmonary conditions, cancer, and allergies is examined, offering a hopeful outlook for the future of medical treatments.

MAJOR CONCLUSIONS

The intranasal administration of EVs offers significant advantages over other delivery methods. By directly delivering EVs to the brain, specifically targeting areas that have been injured, this administration proves to be highly efficient and effective, providing reassurance about the progress in medical treatments. Intranasal delivery is not limited to brain-related conditions. It can also benefit other organs like the lungs and stimulate a mucosal immune response against various pathogens due to the highly vascularized nature of the nasal cavity and airways. Moreover, it has the added benefit of minimizing toxicity to non-targeted organs and allows the EVs to remain longer in the body. As a result, there is a growing emphasis on conducting clinical trials for intranasal administration of EVs, particularly in treating respiratory tract pathologies such as coronavirus disease.

Intranasal Analgesia in Preterm and Term Neonates

The prevention, recognition, and treatment of pain is crucial in the management of neonates. Infants do not tolerate pain better than adults; indeed, the immaturity of the endogenous antalgic system means they exhibit an increased stress response. Pain has been associated with worse cognitive and motor scores, reduced growth trend, reduced brain maturation, and altered corticospinal tract structure. The use of the intranasal route for drug delivery is currently expanding because it has many advantages. In certain contexts, it is preferable over the oral route because of the faster entry of drugs into the circulation, the absence of structural changes by the gastrointestinal environment, and the absence of the hepatic first-pass effect. The pharmacokinetics and pharmacodynamics of drugs commonly used for pain management have peculiar characteristics in infants, especially premature infants. In this article, we summarise the evidence regarding pain management in infants using intranasally administered drugs. We then provide a practical guide to the use of intranasal drugs currently being studied in the neonatal population, focusing on appropriate dosages and indications. Intranasal fentanest appears to be an attractive therapeutic alternative for procedural and palliative neonatal pain management when intravenous access is unavailable in preterm infants. Intranasal midazolam is a valid alternative to consider in term or near-term neonates, especially when the aim is to obtain sedation (and not analgesia, i.e. during magnetic resonance imaging), ketamine has favourable cardiovascular effects and should be considered in specific patients and situations. Intranasal dexmedetomidine is well tolerated in premature neonates. Additionally, endonasal dexmedetomidine can be used in combination with other anaesthetic, sedative, hypnotic, and opioid drugs to allow for dose reduction in sedated neonates.

Protective effect of flavonoids on oxidative stress injury in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, which is mainly caused by the damage of the structure and function of the central nervous system. At present, there are many adverse reactions in market-available drugs, which can't significantly inhibit the occurrence of AD. Therefore, the current focus of research is to find safe and effective therapeutic drugs to improve the clinical treatment of AD. Oxidative stress bridges different mechanism hypotheses of AD and plays a key role in AD. Numerous studies have shown that natural flavonoids have good antioxidant effects. They can directly or indirectly resist -oxidative stress, inhibit Aβ aggregation and Tau protein hyperphosphorylation by activating Nrf2 and other oxidation-antioxidation-related signals, regulating synaptic function-related pathways, promoting mitochondrial autophagy, etc., and play a neuroprotective role in AD. In this review, we summarised the mechanism of flavonoids inhibiting oxidative stress injury in AD in recent years. Moreover, because of the shortcomings of poor biofilm permeability and low bioavailability of flavonoids, the advantages and recent research progress of nano-drug delivery systems such as liposomes and solid lipid nanoparticles were highlighted. We hope this review provides a useful way to explore safe and effective AD treatments.

Dodecyl creatine ester, a promising treatment to deliver creatine to neurons, achieves pharmacology efficacy in creatine transporter deficiency

Dodecyl creatine ester (DCE) is a creatine prodrug currently developed for brain diseases, including creatine transporter deficiency (CTD), an incurable rare genetic disease. A dual strategy combining a prodrug to bypass the non-functional creatine transporter and its delivery via the nose-to-brain pathway has been proposed to replenish creatine levels in cerebral cells, particularly in neurons of CTD patients. In vitro and in vivo studies in various animal models, including wild-type non-human primates and creatine transporter deficient mice, show that formulated DCE, when administered intranasally, achieves significant cerebral distribution up to the target cells, the neurons, and modulates the expression of neuronal markers related to cognitive function at doses intended for patients. These compelling results contribute to a better understanding of the pharmacokinetics and pharmacodynamics of DCE after nasal administration, with a particular focus on the crucial role of the nose-to-brain pathway in DCE distribution.

Intranasal Administrations of AP39-Loaded Liposomes Selectively Deliver H2S to Neuronal Mitochondria to Protect Neonatal Hypoxia-Ischemia by Targeting ERK1/2 and Caspase-1

Mitochondrial dysfunction contributes to the pathology of hypoxia-ischemia (HI) brain damage by aberrant production of ROS. Hydrogen sulfide (H2S) has been demonstrated to exert neuroprotective effects through antioxidant mechanisms. However, the diffusion of H2S in vivo is not specifically targeted and may even be systemically toxic. In this study, based on mitochondria-targeted H2S donor AP39, we fabricated liposomes encapsulating AP39 (AP39@Lip) via intranasal delivery to improve functional recovery after HI brain injury. This study presents that intranasal administration of AP39@Lip was capable of attenuating acute brain injury by inhibiting mitochondrial dysfunction, apoptosis, neuroinflammation, and ROS production in the lesional cortex 3 days after HI brain injury. Similarly, AP39@Lip was observed to restore both short- and long-term function following HI injury without obvious toxicity. Mechanistically, the therapeutic effects of AP39@Lip mainly relied on its colocalization with neuronal mitochondria 24 h after administration and reversed H2S levels in the lesional cortex. Moreover, molecular docking and cellular thermal shift assay suggest that AP39 inhibited the activation of ERK1/2 and caspase-1 by directly binding to ERK1/2 or caspase-1. These results indicate that intranasal administration of AP39@Lip selectively delivered H2S to neuronal mitochondria and mitigated mitochondrial damage following HI insult by targeting ERK1/2 and caspase-1.

A comprehensive insight of innovations and recent advancements in nanocarriers for nose-to-brain drug targeting

Central Nervous System (CNS) disorders are the leading cause of illness and affect the everyday lives of people all around the globe and are predicted to increase tremendously in the upcoming decades. Traditional methods of delivering drugs to the CNS face considerable limitations. Nose-to-brain targeting offers a promising alternative that bypasses the blood-brain barrier (BBB), enabling targeted drug administration to the central nervous system (CNS). Nanotechnology has brought forward innovative solutions to the challenges of drug delivery in CNS disorders. Nanocarriers such as liposomes, nanoparticles, nanoemulsions and dendrimers can enhance drug stability, bioavailability, and targeted delivery to the brain. These nanocarriers are designed to overcome physiological barriers and provide controlled and sustained drug release directly to the CNS. Nanocarrier technology has made significant strides in recent years, enabling more effective and targeted delivery of drugs to the brain. With recent advancements, intranasal delivery coupled with nanocarriers seems to be a promising combination that can provide better clinical profiles, pharmacokinetics, and pharmacodynamics for neurodegenerative disorders. This study focuses on exploring the nose-to-brain drug delivery system, emphasizing the use of various nanocarriers designed for this purpose. Additionally, the study encompasses recent advancements in nanocarrier technology tailored specifically to improve the efficiency of drug administration through the nasal route to the brain.

Nose-to-brain delivery of DHA-loaded nanoemulsions: A promising approach against Alzheimer's disease

Reduced docosahexaenoic acid (DHA) concentrations seem to be associated with an increased risk of Alzheimer's disease (AD), and DHA accretion to the brain across the blood-brain-barrier (BBB) can be modulated by various factors. Therefore, there is an urgent need to identify an efficient and non-invasive method to ensure brain DHA enrichment. In the present study, a safe and stable DHA-enriched nanoemulsion, designed to protect DHA against oxidation, was designed and administered intranasally in a transgenic mouse model of AD, the J20 mice. Intranasal treatment with nanoformulated DHA significantly improved well-being and working spatial memory in six-months-old J20 mice. These behavioral effects were associated with a reduction of amyloid deposition, oxidative stress, and neuroinflammation in brain tissues, which may be partially due to DHA-induced inactivation of the pleiotropic kinase GSK3β. In conclusion, intranasal DHA administration exhibited strong therapeutic effects and disease-modifying benefits in the J20 AD model. Given that DHA has already shown safety and tolerability in healthy human subjects, our results further support the need for clinical trials to assess the potential of this approach in Alzheimer's patients.

Novel Nose-to-brain delivery of carbenoxolone via mucoadhesive solid lipid nanoparticles for Parkinson's symptoms management: In vitro and in vivo evaluation in a rotenone-induced rat model

Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by motor and non-motor symptoms, with limited effective treatment options. This study proposes a novel approach utilizing intranasal delivery of carbenoxolone (CBX) via chitosan-coated solid lipid nanoparticles (CS-coated SLNs) to manage PD symptoms by enhancing CBX delivery and brain targeting. Formulated CS-coated SLNs exhibited favorable quality attributes including particle size (164 ± 0.12 nm), surface charge (18 ± 0.89 mV), high entrapment efficiency (97.98 ± 0.98 %), and sustained drug release profile. In vivo evaluations in a rotenone-induced rat model of PD involved intranasal administration of CBX suspension and CBX-loaded CS-coated SLN (equivalent to 20 mg/kg/day) over four weeks. The CBX nano-formulation group showed significant improvements in motor function, coordination, and balance, as well as modulation of neurotransmitter levels, with increased dopamine and decreased α-synuclein levels compared to the control group. Moreover, the CBX nano-formulation exhibited superior efficacy in reducing neuroinflammation, oxidative stress, and apoptosis markers. Histological examination revealed restored neuronal architecture, suggesting potential neuroprotective effects. In conclusion, mucoadhesive chitosan-coated SLNs offer a promising nasal delivery system overcoming brain drug delivery obstacles facing CBX therapy in PD, paving the way to the development of novel treatments and improved quality of life for PD patients.

Hinokinin Decreases Methamphetamine-Induced Hyperlocomotion via the Regulatory Effects on Dopamine Levels

The global abuse of stimulant methamphetamine (METH) imposes a significant social burden. Despite this, effective therapeutic interventions for mitigating the harmful effects associated with METH-induced central nervous system (CNS) stimulation remain elusive. Chamaecyparis obtusa (hinoki), containing hinokinin as its active constituent, has been identified to exhibit CNS depressant properties. Here, we explored the potential of the hinoki extract and hinokinin in modulating METH-induced hyperlocomotion through the regulation of dopaminergic neuronal activity. We discovered that pretreatment with hinokinin significantly attenuates METH-induced locomotor activity, indicative of reduced CNS stimulation. Furthermore, treatment with hinokinin was observed to inhibit the METH-induced elevation in dopamine levels and the concomitant decrease in dopamine transporter (DAT) function within striatal brain slices of mice. In silico analysis coupled with pull-down assays and the dose-response curve substantiated the direct binding of hinokinin to DAT. We propose that hinokinin mitigates METH-induced hyperlocomotion via the inhibition of dopaminergic neurotransmission, with allosteric modulation of DAT playing a critical role in this regulatory mechanism. Collectively, our research suggests the potential of hinokinin to mitigate dopamine-mediated central nervous system excitation.

Palliative patients who may benefit from intranasal delivery of symptomatic drugs: a two-center observational study evaluated the administration of morphine and dexamethasone in Polish hospices

INTRODUCTION

Patients receiving hospice care at the end of life often suffer from a variety of ailments. They may need medication to alleviate symptoms for the rest of their lives. The most common and recommended way to take opioids and steroids is orally. Less frequently, the subcutaneous or intravenous routes are used. The intranasal route is a relatively uncommon but interesting alternative for administering drugs.

AIM

The study aims to identify hospice patients who may benefit from changing the standard opioid and steroid administration route to intranasal delivery.

MATERIAL AND METHODS

The electronic medical records of all home and inpatient hospice patients (both rural and urban) were analyzed between February and April 2024. The study focused on the magnitude and type of problems associated with taking medications via standard routes and assessed the potential for changing to an intranasal route of administration.

RESULTS

Patients who were prescribed morphine, dexamethasone, or both during co-administration were included in the analysis. Of the 282 patients receiving hospice care over the study period, 95 met the inclusion criteria (33.7%). According to the researcher's original survey 87% of patients experienced issues with taking medications through the standard route. Among the problems related to oral medicines, consciousness disorders were the most significant at 66%. For subcutaneous administration, the main issues were reluctance to inject at 19% and lack of cooperation from caregivers at 20%.

CONCLUSION

The profile of a hospice patient who may benefit from intranasal administration of symptomatic drugs includes patients with impaired consciousness, aversion to subcutaneous injections, and reluctance to administer injections by caregivers.

Ketamine and Esketamine in Clinical Trials: FDA-Approved and Emerging Indications, Trial Trends With Putative Mechanistic Explanations

Ketamine has a long and very eventful pharmacological history. Its enantiomer, esketamine ((S)-ketamine), was approved by the US Food and Drug Administration (FDA) and EMA for patients with treatment-resistant depression (TRD) in 2019. The number of approved indications for ketamine and esketamine continues to increase, as well as the number of clinical trials. This analysis provides a quantitative overview of the use of ketamine and its enantiomers in clinical trials during 2014-2024. A total of 363 trials were manually assessed from clinicaltrial.gov with the search term "Ketamine." The highest number of trials were found for the FDA-approved indications: anesthesia (~22%) and pain management (~28%) for ketamine and TRD for esketamine (~29%). Clinical trials on TRD for both ketamine and esketamine also comprised a large proportion of these trials, and interestingly, have reached phase III and phase IV status. Combinatorial treatment of psychiatric disorders and non-psychiatric conditions with pharmacological and non-pharmacological combinations (electroconvulsive therapy, psychotherapeutic techniques, virtual reality, and transcranial magnetic stimulation) is prevalent. Sub-anesthetic doses of ketamine may represent novel therapeutic avenues in neuropsychiatric conditions, that is, major depression, schizophrenia, and bipolar disorder, where glutamate excitotoxicity and oxidative stress are likely to be involved. The study suggests that the number of ketamine studies will continue to grow and possible ketamine variants can be approved for treatment of additional indications.

Intranasal delivery of mesenchymal stem cell-derived exosomes ameliorates experimental autoimmune encephalomyelitis

BACKGROUND

Exosomes derived from bone marrow mesenchymal stem cells (BMSCs-Exos) have shown therapeutic potential in experimental autoimmune encephalomyelitis (EAE). As a non-invasive method of drug administration, intranasal delivery is anticipated to emerge as a novel option for the treatment of central nervous system (CNS) disorders. Therefore, this study aims to treat EAE by nasal exosomes and explore its specific mechanism, especially its impact on the blood-brain barrier (BBB).

METHODS

BMSCs-Exos were isolated and characterized. An EAE model was then established, and these exosomes were administered intranasally to the mice. Changes in body weight and clinical scores were monitored following treatment to assess the efficacy. Additionally, inflammatory infiltrates and demyelination in the CNS were evaluated, alongside the quantification of expression levels of BBB-related adhesion molecules and tight junction (TJ) proteins.

RESULTS

Intranasal delivery of BMSCs-Exos ameliorates the severity of EAE disease, reducing inflammatory infiltration in the CNS and demyelination in the spinal cord. This treatment did not influence the differentiation of T cells in the spleen. Furthermore, the nasal delivery of BMSCs-Exos enhances the integrity of TJs in the cerebral cortex and spinal cord, as well as inhibiting the expression of adhesion molecules. These exosomes promote the expression of TJ-related markers in bEnd3 cells, including ZO-1, Occludin, and Claudin 5. At the same time, they suppress the expression of adhesion molecule-related markers, such as ICAM1 and VCAM1.

CONCLUSIONS

Our study suggests that intranasal administration of BMSCs-Exos significantly reduces inflammatory infiltration and demyelination in the CNS of EAE mice. Furthermore, this treatment does not influence the differentiation of T cells in the spleen. Additionally, nasal reinfusion of BMSCs-Exos can improve the integrity of the BBB in EAE mice.

Human platelet lysate: a potential therapeutic for intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a major public health challenge worldwide, and is associated with elevated rates of mortality, disability, and morbidity, especially in low- and middle-income nations. However, our knowledge of the detailed molecular processes involved in ICH remains insufficient, particularly those involved in the secondary injury stage, resulting in a lack of effective treatments for ICH. Human platelet lysates (HPL) are abundant in bioactive factors, and numerous studies have demonstrated their beneficial effects on neurological diseases, including their anti-neuroinflammatory ability, anti-oxidant effects, maintenance of blood-brain barrier integrity, and promotion of neurogenesis. In this review, we thoroughly explore the potential of HPL for treating ICH from three critical perspectives: the rationale for selecting HPL as a treatment for ICH, the mechanisms through which HPL contributes to ICH management, and the additional measures necessary for HPL as a treatment for ICH. We elucidate the role of platelets in ICH pathophysiology and highlight the limitations of the current treatment options and advancements in preclinical research on the application of HPL in neurological disorders. Furthermore, historical developments and preparation methods of HPL in the field of biomedicine are discussed. Additionally, we summarize the bioactive molecules present in HPL and their potential therapeutic effects in ICH. Finally, we outline the issues that must be addressed regarding utilizing HPL as a treatment modality for ICH.

A narrative review on potential applications of spanlastics for nose-to-brain delivery of therapeutically active agents

Spanlastics, which are commonly referred to as elastic niosomes, presents a modified advancement in the area of colloidal system based drug delivery carriers. They are different from niosomes, which are non-ionic surfactant vesicles in having an edge activator. Initially, they were described as ocular drug delivery systems in 2011 by Kakkar and Kaur. Spanlastics have discovered a wide range of applications via different routes of administration. The purpose of this article is to provide information about spanlastics, a newly developed drug delivery system for the management of diseases pertaining to the Central Nervous System (CNS) via intranasal route. The article begins with the details on spanlastics and their composition, their benefits over traditional niosomes, and the mechanism underlying their enhanced absorption. Their applications through various routes of administration in a variety of diseases for a variety of drugs have been discussed. Furthermore, the article explains the nose to brain delivery channels and the advantages that this route offers over conventional delivery routes. Finally, the article discusses the studies encompassing the drug candidates that have been formulated as intranasal spanlastics for the management of different diseased conditions along with the future prospects of this emerging drug delivery system.

A comparative study of detomidine delivery via intranasal or intramuscular routes in calves undergoing disbudding

OBJECTIVE

To compare the sedative and physiological effects of intranasal (IN) and intramuscular (IM) delivery of detomidine in calves.

STUDY DESIGN

Prospective, randomized experimental study.

ANIMALS

A total of 20 healthy calves, aged 15.6 ± 4.2 days old, with body masses ranging from 40 to 60 kg.

METHODS

Calves were randomly assigned to be administered detomidine (0.03 mg kg-1) by either IN or IM route. The onset of sedation, duration of sedation and sedation score (SS) were recorded. Heart rate (HR), peripheral arterial hemoglobin oxygen saturation (SpO2), noninvasive systolic and diastolic arterial pressures (SAP and DAP, respectively), respiratory rate (fR) and rectal temperature (RT) were measured immediately before drug delivery (baseline), at 10 (T10), 15 (T15), 20 (T20) and 30 (T30) minutes after drug delivery. Calves underwent disbudding at T25. Comparisons between groups for physiological variables were performed with an independent t-test. Duration of sedation and SS were assessed with a Mann-Whitney test.

RESULTS

Onset of sedation was 6.8 ± 2.3 (mean ± standard deviation) and 14.1 ± 6.6 minutes in groups IM and IN, respectively (p = 0.005). Duration of sedation was 32.5 (26-65) [median (range)] and 33 (26-52) minutes in groups IM and IN, respectively (p = 0.622). SS was significantly higher in the IM group than the IN group at T15 (p = 0.015) and T20 (p = 0.039). HR was significantly higher with IN than with IM at T20 (p = 0.022). RT was significantly lower in IN than in IM at T30 (p = 0.020). fR, SpO2, SAP and DAP did not differ significantly between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The IN delivery of detomidine resulted in a slower onset of sedation compared with IM injection, although the duration of sedation did not differ between the two treatments.

Maresin-like 1 Ameliorates Neuropathology of Alzheimer's Disease in Brains of a Transgenic Mouse Model

(1) Background: Impeded resolution of inflammation contributes substantially to the pathogenesis of Alzheimer's disease (AD); consequently, resolving inflammation is pivotal to the amelioration of AD pathology. This can potentially be achieved by the treatment with specialized pro-resolving lipid mediators (SPMs), which should resolve neuroinflammation in brains. (2) Methods: Here, we report the histological effects of long-term treatment with an SPM, maresin-like 1 (MarL1), on AD pathogenesis in a transgenic 5xFAD mouse model. (3) Results: MarL1 treatment reduced Aβ overload, curbed the loss of neurons in brains especially cholinergic neurons associated with cleaved-caspase-3-associated apoptotic degeneration, reduced microgliosis and the pro-inflammatory M1 polarization of microglia, curbed the AD-associated decline in anti-inflammatory Iba1+Arg-1+-M2 microglia, inhibited phenotypic switching to pro-inflammatory N1 neutrophils, promoted the blood-brain barrier-associated tight-junction protein claudin-5 and decreased neutrophil leakage in 5xFAD brains, and induced the switch of neutrophils toward the inflammation-resolving N2 phenotype. (4) Conclusions: Long-term administration of MarL1 mitigates AD-related neuropathogenesis in brains by curbing neuroinflammation and neurodegeneration, based on the histological results. These findings provide preclinical leads and mechanistic insights for the development of MarL1 into an effective modality to ameliorate AD pathogenesis.

Arginine vasopressin induces analgesic effects and inhibits pyramidal cells in the anterior cingulate cortex in spared nerve injured mice

Neuropathic pain (NP) is a severe disease caused by a primary disease or lesion affecting the somatosensory nervous system. It is reported that NP is related to the increased activity of glutamatergic pyramidal cells and changed neural oscillations in the anterior cingulate cortex (ACC). Arginine vasopressin (AVP), a neurohypophyseal hormone, has been shown to cause pain-alleviating effects when applied to the peripheral system. However, the extent to which, and the mechanisms by which, AVP induces analgesic effects in the central nervous system remains unclear. In the present study, we observed that intranasal delivery of AVP inhibited mechanical pain, thermal pain, and spontaneous pain sensitivity in mice with spared nerve injury. Meanwhile, AVP application exclusively reduced the FOS expression in the pyramidal cells but not interneurons in the ACC. In vivo electrophysiological recording of the ACC further showed that AVP application not only inhibited the theta oscillation in local field potential analysis but also reduced the firing rate of spikes of pyramidal cells in the ACC in neuropathic pain mice. In summary, AVP induces analgesic effects by inhibiting neural theta oscillations and the spiking of pyramidal cells of the ACC in mice with neuropathic pain, which should provide new potential noninvasive methods for clinical treatment of chronic pain.NEW & NOTEWORTHY Following intranasal administration of arginine vasopressin (AVP), the pain thresholds for mechanical and thermal nociception significantly increased in the spared nerve injury (SNI) group; exogenous intranasal delivery of AVP improved the physical coordination of SNI mice, resulting in an analgesic effect; AVP treatment significantly reduced the increased firing rate of PYRACC of the SNI group; AVP treatment significantly inhibited the elevated theta oscillation in the anterior cingulate cortex (ACC) in SNI mice.

Exploring the Potential of Nasal Drug Delivery for Brain Targeted Therapy: A Detailed Analysis

The brain is a sensitive organ with numerous essential functions and complex mechanisms. It is secluded and safeguarded from the external environment as part of the central nervous system (CNS), serving as a sanctuary. By regulating their selective and specific absorption, efflux, and metabolism in the brain, the CNS controls brain homeostasis and the transit of endogenous and foreign substances. The mechanism which protects the brain from environmental chemicals, also prevent the entry of therapeutic chemicals to it. The delivery of molecules to the brain is hindered by several major barriers, such as the blood-brain barrier (BBB), blood-cerebrospinal fluid barrier (BCSFB), and blood-tumor barrier. BBB is formed by the combination of cerebral endothelial cells, astrocytes, neurons, pericytes and microglia. It is a tight junction of capillary endothelial cells, preventing the diffusion of solute into the brain. BCSFB is the second barrier, located at the choroid plexus, separating the blood from cerebrospinal fluid (CSF). It is comparatively more permeable than BBB. An uneven distribution of microvasculature across the tumor interstitial compromises drug delivery to neoplastic cells of a solid tumor, resulting in spatially inconsistent drug administration. Nasal drug delivery to the brain is a method of drug delivery that tries to deliver therapeutic substances directly from the nasal cavity to the central nervous system including the brain. In this review, besides the role of barriers we have discussed in detail about approaches adapted to deliver drugs to the brain along with mechanisms through nasal route. Further, different commercial formulations, clinical trials and patents have been thoroughly elaborated to date. The findings suggest that the nose-to-brain drug delivery method holds promise as an evolving approach, potentially contributing to the specific and targeted delivery of drugs into the brain.

Intranasal Treatment with Cannabinoid 2 Receptor Agonist HU-308 Ameliorates Cold Sensitivity in Mice with Traumatic Trigeminal Neuropathic Pain

Post-traumatic trigeminal neuropathy (PTTN) is a sensory abnormality caused by injury to the trigeminal nerve during orofacial surgery. However, existing analgesics are ineffective against PTTN. Abnormal microglial activation in the caudal part of the spinal trigeminal nucleus caudal part (Sp5C), where the central trigeminal nerve terminals reside, plays an important role in PTTN pathogenesis. Therefore, regulating microglial activity in Sp5C appears to be an important approach to controlling pain in PTTN. Cannabinoid receptor 2 (CB2) is expressed in immune cells including microglia, and its activation has anti-inflammatory effects. The current study demonstrates that the repeated intranasal administration of CB2 agonist HU-308 ameliorates the infraorbital nerve cut (IONC)-induced hyperresponsiveness to acetone (cutaneous cooling). The therapeutic efficacy of oral HU-308 was found to be less pronounced in alleviating cold hypersensitivity in IONC mice compared to intranasal administration, indicating the potential advantages of the intranasal route. Furthermore, repeated intranasal administration of HU-308 suppressed the activation of Sp5C microglia in IONC mice. Additionally, pretreatment with the CB2 antagonist, SR 144528, significantly blocked the anti-nociceptive effect of repeated intranasal administration of HU-308 on cold hypersensitization in IONC mice. These data suggest that the continuous stimulation of CB2 ameliorates PTTN-induced pain via the inhibition of microglial activation. Thus, CB2 agonists are potential candidates for novel therapeutic agents against PTTN.

Laminar Fluid Ejection for Olfactory Drug Delivery: A Proof of Concept Study

Focal intranasal drug delivery to the olfactory cleft is a promising avenue for pharmaceuticals targeting the brain. However, traditional nasal sprays often fail to deliver enough medication to this specific area. We present a laminar fluid ejection (LFE) method for precise delivery of medications to the olfactory cleft. Using a 3D-printed model of the nasal passages, we determined the precise velocity and angle of insertion needed to deposit fluid at the olfactory cleft. Then, we conducted three proof-of-concept in-vivo imaging studies to confirm olfactory delivery in humans. First, we used Technetium-99 (a radiolabeled tracer) and methylene blue (a laboratory-made dye) to visualize olfactory deposition. Both tracers showed successful deposition. In a separate study, we used functional MRI (fMRI), to compare our LFE method with a conventional nasal spray while delivering insulin. From the fMRI results, we qualitatively observed focal decreases in brain activity in prefrontal cortex following insulin delivery. Overall, these preliminary results suggest that LFE offers a targeted approach to olfactory drug delivery, opening opportunities for access to the brain.Clinical and Translational Impact Statement - Focal deposition at the olfactory cleft is a promising target for delivering medication to the brain. We present in-human tests of a laminar fluid ejection method for intranasal drug delivery and demonstrate improvements over conventional nasal spray.

Nanotechnological approaches for efficient N2B delivery: from small-molecule drugs to biopharmaceuticals

Central nervous system diseases negatively affect patients and society. Providing successful noninvasive treatments for these diseases is challenging because of the presence of the blood-brain barrier. While protecting the brain's homeostasis, the barrier limits the passage of almost all large-molecule drugs and most small-molecule drugs. A noninvasive method, nose-to-brain delivery (N2B delivery) has been proposed to overcome this challenge. By exploiting the direct anatomical interaction between the nose and the brain, the drugs can reach the target, the brain. Moreover, the drugs can be encapsulated into various drug delivery systems to enhance physicochemical characteristics and targeting success. Many preclinical data show that this strategy can effectively deliver biopharmaceuticals to the brain. Therefore, this review focuses on N2B delivery while giving examples of different drug delivery systems suitable for the applications. In addition, we emphasize the importance of the effective delivery of monoclonal antibodies and RNA and stress the recent literature tackling this challenge. While giving examples of nanotechnological approaches for the effective delivery of small or large molecules from the current literature, we highlight the preclinical studies and their results to prove the strategies' success and limitations.

An Update on Recent Drug Delivery Systems Targeting Brain Diseases via the Transnasal Pathway

OBJECTIVE

To explore the potential of transnasal drug delivery systems (DDS) as an effective means of bypassing the bloodbrain barrier (BBB) for enhanced central nervous system (CNS) targeting, aiming to improve therapeutic outcomes for CNS disorders while reducing systemic side effects.

METHODS

A review of current and emerging DDS technologies, including polymer nanoparticles, liposomes, and micelles, was conducted to assess their suitability for precision-targeted delivery to the brain through the transnasal route.

RESULTS

The investigated DDS demonstrate promising capabilities for CNS targeting via the nasal pathway, effectively preserving both the nasal mucosa and CNS integrity. These systems enhance drug precision within neural tissues, potentially improving therapeutic outcomes without harming adjacent tissues.

CONCLUSIONS

Transnasal DDS offer a promising alternative to traditional delivery methods, with significant potential to advance the treatment of cerebrovascular diseases, neurodegenerative disorders, brain tumors, and psychiatric conditions. This approach represents an evolving frontier in neurotherapeutics, with the potential to transform CNS drug delivery practices.

Drop to Gate Nasal Drops Attenuates Sepsis-Induced Cognitive Dysfunction

Nasal administration can bypass the blood-brain barrier and directly deliver drugs to the brain, providing a non-invasive route for central nervous system (CNS) diseases. Inspired by the appearance that a gate can block the outside world and the characteristics of the sol-gel transition can form a "gate" in the nasal cavity, a Drop to Gate nasal drop (DGND) is designed to set a gate in nose, which achieves protecting role from the influence of nasal environment. The DGND demonstrates the efficiency and application prospect of delivering drugs to the brain through the N-to-B. The effective concentration of single administration is increased through the hydrophobic interaction between C8-GelMA and SRT1720 (SA), and then cross-linked under UV to form nanogel, which can respond to MMP in the inflammatory microenvironment of sepsis-induced cognitive dysfunction. Finally, the SA/nanogel is compounded into the thermogel, which can respond to the nasal cavity temperature to form DGND in situ, increasing the residence time and delivery efficiency of drugs in the nasal cavity. In vitro, the DGND alleviates lipopolysaccharides (LPS)-induced BV2 inflammation. In vivo, DGND effectively targets the nasal mucosa and deliver drugs to the brain, which activate Sirt1 to alleviate inflammation mediated by microglia and improve cognitive dysfunction in sepsis mice.

Technological Strategies Applied to Pharmaceutical Systems for Intranasal Administration of Drugs Intended for Neurological Treatments: A Review

The complexity of treating neurological diseases has meant that new strategies have had to be developed to deliver drugs to the brain more efficiently and safely. Intranasal drug delivery is characterized by its ease of administration, safety, and rapid delivery directly from the nose to the brain. Several strategies have been developed to improve the delivery of drugs to the brain via nasal administration. These include the use of mucoadhesive and thermoresponsive polymers and their combination into polymer blends, as well as the use of liposomes, niosomes, and nano- and microemulsions. Therefore, this review focuses on technologies for developing pharmaceutical systems aimed at delivery via the nose to the brain, contributing to new treatments for difficult neurological disorders. Some of the most common and difficult-to-treat neurological conditions, the intranasal route of administration, and the anatomy of the nasal cavity have been discussed, as well as factors that may influence the absorption of drugs administered into the nose. The types of intranasal formulations and the devices that can be used to administer these products are also discussed in this review. Strategies for improving the transport of bioactive agents and increasing bioavailability are highlighted. The technologies discussed in this review can facilitate the development of formulations with improved properties, such as drug release and mucoadhesiveness, which have several advantages for patients requiring complex neurological treatments.

IL-33/ST2 signaling in monocyte-derived macrophages maintains blood-brain barrier integrity and restricts infarctions early after ischemic stroke

BACKGROUND

Brain microglia and infiltrating monocyte-derived macrophages are vital in preserving blood vessel integrity after stroke. Understanding mechanisms that induce immune cells to adopt vascular-protective phenotypes may hasten the development of stroke treatments. IL-33 is a potent chemokine released from damaged cells, such as CNS glia after stroke. The activation of IL-33/ST2 signaling has been shown to promote neuronal viability and white matter integrity after ischemic stroke. The impact of IL-33/ST2 on blood-brain barrier (BBB) integrity, however, remains unknown. The current study fills this gap and reveals a critical role of IL-33/ST2 signaling in macrophage-mediated BBB protection after stroke.

METHODS

Transient middle cerebral artery occlusion (tMCAO) was performed to induce ischemic stroke in wildtype (WT) versus ST2 knockout (KO) male mice. IL-33 was applied intranasally to tMCAO mice with or without dietary PLX5622 to deplete microglia/macrophages. ST2 KO versus WT bone marrow or macrophage cell transplantations were used to test the involvement of ST2+ macrophages in BBB integrity. Macrophages were cocultured in transwells with brain endothelial cells (ECs) after oxygen-glucose deprivation (OGD) to test potential direct effects of IL33-treated macrophages on the BBB in vitro.

RESULTS

The ST2 receptor was expressed in brain ECs, microglia, and infiltrating macrophages. Global KO of ST2 led to more IgG extravasation and loss of ZO-1 in cerebral microvessels 3 days post-tMCAO. Intranasal IL-33 administration reduced BBB leakage and infarct severity in microglia/macrophage competent mice, but not in microglia/macrophage depleted mice. Worse BBB injury was observed after tMCAO in chimeric WT mice reconstituted with ST2 KO bone marrow, and in WT mice whose monocytes were replaced by ST2 KO monocytes. Macrophages treated with IL-33 reduced in vitro barrier leakage and maintained tight junction integrity after OGD. In contrast, IL-33 exerted minimal direct effects on the endothelial barrier in the absence of macrophages. IL-33-treated macrophages demonstrated transcriptional upregulation of an array of protective factors, suggesting a shift towards favorable phenotypes.

CONCLUSION

Our results demonstrate that early-stage IL-33/ST2 signaling in infiltrating macrophages reduces the extent of acute BBB disruption after stroke. Intranasal IL-33 administration may represent a new strategy to reduce BBB leakage and infarct severity.

Enhancing Acute Migraine Treatment: Exploring Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for the Nose-to-Brain Route

Migraine has a high prevalence worldwide and is one of the main disabling neurological diseases in individuals under the age of 50. In general, treatment includes the use of oral analgesics or non-steroidal anti-inflammatory drugs (NSAIDs) for mild attacks, and, for moderate or severe attacks, triptans or 5-HT1B/1D receptor agonists. However, the administration of antimigraine drugs in conventional oral pharmaceutical dosage forms is a challenge, since many molecules have difficulty crossing the blood-brain barrier (BBB) to reach the brain, which leads to bioavailability problems. Efforts have been made to find alternative delivery systems and/or routes for antimigraine drugs. In vivo studies have shown that it is possible to administer drugs directly into the brain via the intranasal (IN) or the nose-to-brain route, thus avoiding the need for the molecules to cross the BBB. In this field, the use of lipid nanoparticles, in particular solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), has shown promising results, since they have several advantages for drugs administered via the IN route, including increased absorption and reduced enzymatic degradation, improving bioavailability. Furthermore, SLN and NLC are capable of co-encapsulating drugs, promoting their simultaneous delivery to the site of therapeutic action, which can be a promising approach for the acute migraine treatment. This review highlights the potential of using SLN and NLC to improve the treatment of acute migraine via the nose-to-brain route. First sections describe the pathophysiology and the currently available pharmacological treatment for acute migraine, followed by an outline of the mechanisms underlying the nose-to-brain route. Afterwards, the main features of SLN and NLC and the most recent in vivo studies investigating the use of these nanoparticles for the treatment of acute migraine are presented.

A review of chitosan-based nanocarriers as drug delivery systems for brain diseases: Critical challenges, outlooks and promises

The administration of medicinal drugs orally or systemically limits the treatment of specific central nervous system (CNS) illnesses, such as certain types of brain cancers. These methods can lead to severe adverse reactions and inadequate transport of drugs to the brain, resulting in limited effectiveness. The CNS homeostasis is maintained by various barriers within the brain, such as the endothelial, epithelial, mesothelial, and glial barriers, which strictly control the movement of chemicals, solutes, and immune cells. Brain capillaries consist of endothelial cells (ECs) and perivascular pericytes, with pericytes playing a crucial role in maintaining the blood-brain barrier (BBB), influencing new blood vessel formation, and exhibiting secretory capabilities. This article summarizes the structural components and anatomical characteristics of the BBB. Intranasal administration, a non-invasive method, allows drugs to reach the brain by bypassing the BBB, while direct cerebral administration targets specific brain regions with high concentrations of therapeutic drugs. Technical and mechanical tools now exist to bypass the BBB, enabling the development of more potent and safer medications for neurological disorders. This review also covers clinical trials, formulations, challenges, and patents for a comprehensive perspective.

Recent developments in intranasal drug delivery of nanomedicines for the treatment of neuropsychiatric disorders

Neuropsychiatric disorders are multifaceted syndromes with confounding neurological explanations. It includes anxiety, depression, autism spectrum disorder, attention deficit hyperactivity disorder, schizophrenia, Tourette's syndrome, delirium, dementia, vascular cognitive impairment, and apathy etc. Globally, these disorders occupy 15% of all diseases. As per the WHO, India has one of the largest populations of people with mental illnesses worldwide. The blood-brain barrier (BBB) makes it extremely difficult to distribute medicine to target cells in the brain tissues. However, it is possible through novel advancements in nanotechnology, molecular biology, and neurosciences. One such cutting-edge delivery method, nose-to-brain (N2B) drug delivery using nanoformulation (NF), overcomes traditional drug formulation and delivery limitations. Later offers more controlled drug release, better bioavailability, improved patient acceptance, reduced biological interference, and circumvention of BBB. When medicines are delivered via the intranasal (IN) route, they enter the nasal cavity and go to the brain via connections between the olfactory and trigeminal nerves and the nasal mucosa in N2B. Delivering phytochemical, bioactive and synthetic NF is being investigated with the N2B delivery strategy. The mucociliary clearance, enzyme degradation, and drug translocations by efflux mechanisms are significant issues associated with N2B delivery. This review article discusses the types of neuropsychiatric disorders and their treatment with plant-derived as well as synthetic drug-loaded NFs administered via the IN-delivery system. In conclusion, this review provided a comprehensive and critical overview of the IN applicability of plant-derived NFs for psychiatric disorders.

A comprehensive review on organ-on-chips as powerful preclinical models to study tissue barriers

In the preclinical stage of drug development, 2D and 3D cell cultures under static conditions followed by animal models are utilized. However, these models are insufficient to recapitulate the complexity of human physiology. With the developing organ-on-chip (OoC) technology in recent years, human physiology and pathophysiology can be modeled better than traditional models. In this review, the need for OoC platforms is discussed and evaluated from both biological and engineering perspectives. The cellular and extracellular matrix components are discussed from a biological perspective, whereas the technical aspects such as the intricate working principles of these systems, the pivotal role played by flow dynamics and sensor integration within OoCs are elucidated from an engineering perspective. Combining these two perspectives, bioengineering applications are critically discussed with a focus on tissue barriers such as blood-brain barrier, ocular barrier, nasal barrier, pulmonary barrier and gastrointestinal barrier, featuring recent examples from the literature. Furthermore, this review offers insights into the practical utility of OoC platforms for modeling tissue barriers, showcasing their potential and drawbacks while providing future projections for innovative technologies.

Hypothalamic circuits and aging: keeping the circadian clock updated

Over the past century, age-related diseases, such as cancer, type-2 diabetes, obesity, and mental illness, have shown a significant increase, negatively impacting overall quality of life. Studies on aged animal models have unveiled a progressive discoordination at multiple regulatory levels, including transcriptional, translational, and post-translational processes, resulting from cellular stress and circadian derangements. The circadian clock emerges as a key regulator, sustaining physiological homeostasis and promoting healthy aging through timely molecular coordination of pivotal cellular processes, such as stem-cell function, cellular stress responses, and inter-tissue communication, which become disrupted during aging. Given the crucial role of hypothalamic circuits in regulating organismal physiology, metabolic control, sleep homeostasis, and circadian rhythms, and their dependence on these processes, strategies aimed at enhancing hypothalamic and circadian function, including pharmacological and non-pharmacological approaches, offer systemic benefits for healthy aging. Intranasal brain-directed drug administration represents a promising avenue for effectively targeting specific brain regions, like the hypothalamus, while reducing side effects associated with systemic drug delivery, thereby presenting new therapeutic possibilities for diverse age-related conditions.

Understanding central nervous system fluid networks: Historical perspectives and a revised model for clinical neurofluid imaging

The central nervous system (CNS) lacks traditionally defined lymphatic vasculature. However, CNS tissues and barriers compartmentalize the brain, spinal cord, and adjacent spaces, facilitating the transmittal of fluids, metabolic wastes, immune cells, and vital signals, while more conventional lymphatic pathways in the meninges, cervicofacial and paraspinal regions transmit efflux fluid and molecules to peripheral lymph and lymph nodes. Thus, a unique and highly organized fluid circulation network encompassing intraparenchymal, subarachnoid, dural, and extradural segments functions in unison to maintain CNS homeostasis. Pathways involved in this system have been under investigation for centuries and continue to be the source of considerable interest and debate. Modern imaging and microscopy technologies have led to important breakthroughs pertaining to various elements of CNS fluid circuitry and exchange over the past decade, thus enhancing knowledge on mechanisms of mammalian CNS maintenance and disease. Yet, to better understand precise anatomical routes, the physiology and clinical significance of these CNS pathways, and potential therapeutic targets in humans, fluid conduits, flow-regulating factors, and tissue effects must be analyzed systematically and in a global manner in persons across age, demographical factors, and disease states. Here, we illustrate the system-wide nature of intermixing CNS fluid networks, summarize historical and clinical studies, and discuss anatomical and physiological similarities and differences that are relevant for translation of evidence from mice to humans. We also review Cushing's classical model of cerebrospinal fluid flow and present a new framework of this "third circulation" that emphasizes previously unexplained complexities of CNS fluid circulation in humans. Finally, we review future directions in the field, including emerging theranostic techniques and MRI studies required in humans.

Advanced Noninvasive Strategies for the Brain Delivery of Therapeutic Proteins and Peptides

Recent years have witnessed rapid progress in the discovery of therapeutic proteins and peptides for the treatment of central nervous system (CNS) diseases. However, their clinical applications have been considerably hindered by challenges such as low biomembrane permeability, poor stability, short circulation time, and the formidable blood-brain barrier (BBB). Recently, substantial improvements have been made in understanding the dynamics of the BBB and developing efficient approaches for delivering proteins and peptides to the CNS, especially by using various nanoparticles. Herein, we present an overview of the up-to-date understanding of the BBB under physiological and pathological conditions, emphasizing their effects on brain drug delivery. We summarize advanced strategies and elucidate the underlying mechanisms for delivering proteins and peptides to the brain. We highlight the developments and applications of nanocarriers in treating CNS diseases via BBB crossing. We also provide critical opinions on the limitations and obstacles of the current strategies and put forward prospects for future research.

Bioinspired Approaches for Central Nervous System Targeted Gene Delivery

Disorders of the central nervous system (CNS) which include a wide range of neurodegenerative and neurological conditions have become a serious global issue. The presence of CNS barriers poses a significant challenge to the progress of designing effective therapeutic delivery systems, limiting the effectiveness of drugs, genes, and other therapeutic agents. Natural nanocarriers present in biological systems have inspired researchers to design unique delivery systems through biomimicry. As natural resource derived delivery systems are more biocompatible, current research has been focused on the development of delivery systems inspired by bacteria, viruses, fungi, and mammalian cells. Despite their structural potential and extensive physiological function, making them an excellent choice for biomaterial engineering, the delivery of nucleic acids remains challenging due to their instability in biological systems. Similarly, the efficient delivery of genetic material within the tissues of interest remains a hurdle due to a lack of selectivity and targeting ability. Considering that gene therapies are the holy grail for intervention in diseases, including neurodegenerative disorders such as Alzheimer's disease, Parkinson's Disease, and Huntington's disease, this review centers around recent advances in bioinspired approaches to gene delivery for the prevention of CNS disorders.

Microneedle-mediated drug delivery for neurological diseases

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

Small Scale, Big Impact: Nanotechnology-Enhanced Drug Delivery for Brain Diseases

Central nervous system (CNS) diseases, ranging from brain cancers to neurodegenerative disorders like dementia and acute conditions such as strokes, have been heavily burdening healthcare and have a direct impact on patient quality of life. A significant hurdle in developing effective treatments is the presence of the blood-brain barrier (BBB), a highly selective barrier that prevents most drugs from reaching the brain. The tight junctions and adherens junctions between the endothelial cells and various receptors expressed on the cells make the BBB form a nonfenestrated and highly selective structure that is crucial for brain homeostasis but complicates drug delivery. Nanotechnology offers a novel pathway to circumvent this barrier, with nanoparticles engineered to ferry drugs across the BBB, protect drugs from degradation, and deliver medications to the designated area. After years of development, nanoparticle optimization, including sizes, shapes, surface modifications, and targeting ligands, can enable nanomaterials tailored to specific brain drug delivery settings. Moreover, smart nano drug delivery systems can respond to endogenous and exogenous stimuli that control subsequent drug release. Here, we address the importance of the BBB in brain disease treatment, summarize different delivery routes for brain drug delivery, discuss the cutting-edge nanotechnology-based strategies for brain drug delivery, and further offer valuable insights into how these innovations in nanoparticle technology could revolutionize the treatment of CNS diseases, presenting a promising avenue for noninvasive, targeted therapeutic interventions.

Increased alpha-synuclein and neuroinflammation in the substantia nigra triggered by systemic inflammation are reversed by targeted inhibition of the receptor for advanced glycation end products (RAGE)

The receptor for advanced glycation end products (RAGE) is a protein of the immunoglobulin superfamily capable of regulating inflammation. Considering the role of this receptor in the initiation and establishment of neuroinflammation, and the limited understanding of the function of RAGE in the maintenance of this condition, this study describes the effects of RAGE inhibition in the brain, through an intranasal treatment with the antagonist FPS-ZM1, in an animal model of chronic neuroinflammation induced by acute intraperitoneal injection of lipopolysaccharide (LPS). Seventy days after LPS administration (2 mg/kg, i.p.), Wistar rats received, intranasally, 1.2 mg of FPS-ZM1 over 14 days. On days 88 and 89, the animals were submitted to the open-field test and were killed on day 90 after the intraperitoneal injection of LPS. Our results indicate that blockade of encephalic RAGE attenuates LPS-induced chronic neuroinflammation in different brain regions. Furthermore, we found that intranasal FPS-ZM1 administration reduced levels of gliosis markers, RAGE ligands, and α-synuclein in the substantia nigra pars compacta. Additionally, the treatment also reversed the increase in S100 calcium-binding protein B (RAGE ligand) in the cerebrospinal fluid and the cognitive-behavioral deficits promoted by LPS-less time spent in the central zone of the open-field arena (more time in the lateral zones), decreased total distance traveled, and increased number of freezing episodes. In summary, our study demonstrates the prominent role of RAGE in the maintenance of a chronic neuroinflammatory state triggered by a single episode of systemic inflammation and also points to possible future RAGE-based therapeutic approaches to treat conditions in which chronic neuroinflammation and increased α-synuclein levels could play a relevant role, such as in Parkinson's disease.

Enolase inhibitors as therapeutic leads for Naegleria fowleri infection

Infections with the pathogenic free-living amoebae Naegleria fowleri can lead to life-threatening illnesses including catastrophic primary amoebic meningoencephalitis (PAM). Efficacious treatment options for these infections are lacking and the mortality rate remains >95% in the US. Glycolysis is very important for the infectious trophozoite lifecycle stage and inhibitors of glucose metabolism have been found to be toxic to the pathogen. Recently, human enolase 2 (ENO2) phosphonate inhibitors have been developed as lead agents to treat glioblastoma multiforme (GBM). These compounds, which cure GBM in a rodent model, are well-tolerated in mammals because enolase 1 (ENO1) is the predominant isoform used systemically. Here, we describe findings that demonstrate these agents are potent inhibitors of N. fowleri ENO (NfENO) and are lethal to amoebae. In particular, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX) was a potent enzyme inhibitor (IC50 = 0.14 ± 0.04 μM) that was toxic to trophozoites (EC50 = 0.21 ± 0.02 μM) while the reported CC50 was >300 μM. Molecular docking simulation revealed that HEX binds strongly to the active site of NfENO with a binding affinity of -8.6 kcal/mol. Metabolomic studies of parasites treated with HEX revealed a 4.5 to 78-fold accumulation of glycolytic intermediates upstream of NfENO. Last, nasal instillation of HEX increased longevity of amoebae-infected rodents. Two days after infection, animals were treated for 10 days with 3 mg/kg HEX, followed by one week of observation. At the end of the one-week observation, eight of 12 HEX-treated animals remained alive (resulting in an indeterminable median survival time) while one of 12 vehicle-treated rodents remained, yielding a median survival time of 10.9 days. However, intranasal HEX delivery was not curative as brains of six of the eight survivors were positive for amoebae. These findings suggest that HEX requires further evaluation to develop as a lead for treatment of PAM.