Stimuli-responsive In situ gelling system for nose-to-brain drug delivery

Intranasal administration of antiseizure drugs using new formulation trends: one step closer to reach clinical trials

INTRODUCTION

Although there are numerous options for epilepsy treatment, its effective control continues unsatisfactory. Thus, search for alternative therapeutic options to improve the efficacy/safety binomial of drugs becomes very attractive to investigate. In this context, intranasal administration of antiseizure drugs formulated on state-of-the-art nanosystems can be a promising strategy.

AREAS COVERED

This work gives a comprehensive overview of different intranasal nanosystems for antiseizure drug administration developed and evaluated on preclinical studies over the last 10 years and published in 'PubMed' and 'Web of Science' databases. Additionally, it highlights their pharmaceutical critical quality attributes and in vivo pharmacological outputs that might infer possible results when transposing to clinical trials.

EXPERT OPINION

Research into optimized nanosystems encapsulating antiseizure drugs to enhance direct nose-to-brain delivery has increased over the last years. Particularly, the interest in formulating first- and second-generation antiseizure drugs in nanoparticles is here highlighted, having demonstrated its in vivo safety and improvement on pharmacokinetic and efficacy outputs. Still, none of them were brought to clinical trials. Thus, considering the existing barriers between preclinical and clinical trials, if supported by robust and targeted quality by design approaches, intranasal drug delivery can be presented as a valid and superior alternative for epilepsy treatment.

Nanosystems at Nexus: Navigating Nose-to-Brain Delivery for Glioblastoma Treatment

Glioblastoma multiforme (GBM) is considered to be one of the most devastating brain tumors with a shorter life expectancy. Several factors contribute to the dismal prognosis of GBM patients including the complicated nature of GBM, the ability of tumor cells to resist treatment, and the difficulty of delivering drugs to the brain because of barriers like the blood-brain barrier (BBB) and blood-tumor barrier (BTB). The unique challenges posed by the BBB in delivering therapeutic agents to the brain have led to the development of innovative nanotechnology-based approaches. By exploiting the olfactory/trigeminal pathway, nanosystems offer a promising strategy for targeted drug delivery to the brain, glioblastoma tumors in particular. This review contemplates varied nanocarriers, including polymeric nanoparticles, lipid-based nanosystems, in situ gel formulations, peptide, and stem cell-based nanoformulations, signifying their utility in brain targeting with minimal systemic side effects. Emerging trends in gene therapy and immunotherapy in the context of GBM treatment have also been discussed. Since safety is a paramount aspect for any drug product to get approved, this review also delves into toxicological considerations associated with intranasal delivery of nanosystems. Regulatory aspects and critical factors for the successful development of intranasal products are also explored in this review. Overall, this review underscores the significant advancements in nanotechnology for nose-to-brain delivery and its potential impact on GBM management.

Preparation, In-vitro, Ex-vivo, and Pharmacokinetic Study of Lasmiditan as Intranasal Nanoemulsion-based In Situ Gel

BACKGROUND

Lasmiditan (LAS) is a recently developed antimigraine drug and was approved in October, 2019 for the treatment of acute migraines; however, it suffers from low oral bioavailability, which is around 40%.

OBJECTIVES

This study aimed to improve the LAS bioavailability via formulation as nanoemulsionbased in situ gel (NEIG) given intranasally and then compare the traditional aqueous-LASsuspension (AQS) with the two successful intranasal prepared formulations (NEIG 2 and NEIG 5) in order to determine its relative bioavailability (F-relative) via using rabbits.

METHODS

Two successfully prepared nanoemulsion (NE) formulas, a and b, were selected for the incorporation of different percentages of pH-sensitive in situ gelling polymer (Carbopol 934) to prepare NEIGs 1, 2, 3, 4, 5, and 6. The pH, gelation capacity, gel strength, and viscosity were predicted for the prepared NEIGs. The release (in vitro) and the nasal permeation (ex vivo) were determined for NEIG 2 and 5, and then both were subjected to pharmacokinetics in vivo studies. Eighteen male rabbits weighing 2.0 to 2.5 kg were employed in the parallel design study. The body surface area (BSA) normalization method was applied for LAS dose calculation. Serial blood samples were taken out and subjected to drug analysis using the HPLC method previously developed and validated by Kumar et al. Primary pharmacokinetics parameters, including maximum drug concentration in plasma (Cmax), time to reach C-max (T-max), and area under the concentration-time curve from time zero to affinity (AUCt0-∞) were calculated. Both NE (a and b), together with NEIG (2 and 5) formulas, were subjected to the stability study. Finally, a nasal ciliotoxicity study was carried out to evaluate the nasal toxicity of developed NEIGs 2 and 5.

RESULTS

The results showed that NEIGs 2 and 5 could be selected as the optimized NEIGs as both achieved 100% permeation within 20 min and then released within 25 and 35 min, respectively, thus achieving 3.3 folds with higher permeation percentages as compared to the AQS. Both NEIGs 2 and 5 exerted comparable release and permeation values as the corresponding NE a and b with more residence time in order to overcome the normal nasal physiological clearance. The values of C-max, Tmax, and AUC0- ∞ for NEIG 2 and NEIG 5 were 8066 ± 242 ng/ml, 0.75 ± 0.05 h, 19616.86 ± 589 ng. h/ml, and 7975.67 ± 239 ng/ml, 1.0 ± 0.05 h, 17912.36 ± 537 ng. h/ml, respectively, compared to the traditional AQS, which is equal to 4181.09 ± 125 ng/ml, 2 ± 0.2 h, and 8852.27 ± 266 ng. h/ml, respectively. It was discovered that NEIGs 2 and 5 had better intranasal delivery of LAS and could significantly (p < 0.05) achieve a higher value of permeability coefficient (3.3 folds) and 2.5 folds improvement in bioavailability when compared to AQS. The NE a, NE b, NEIG2, and NEIG5 formulations showed good stability at various temperatures. According to the nasal ciliotoxicity study, the nasal mucosal membrane, which was treated with NEIG 5, showed irritation with a bit of damage. However, damage was not observed when it was treated with NEIG 2, indicating the biocompatibility of the last one to be selected as the optimum formula.

CONCLUSION

NEIG 2 and NEIG 5 are promising new intranasal formulas with a faster onset of action and greater bioavailability than the oral dosage form (AQS). Finally, the selected optimum gold formula that will be ready for further clinical study is NEIG 2.

A Review on Lipid-based Nanoformulations for Targeting Brain through Non-invasive Nasal Route

The nasal method for administering nanoformulations to the brain has been examined and proven successful by prior investigators. For the treatment of central nervous system (CNS) disorders such as neuropsychiatric, depression, Alzheimer and anxiety, intranasal administration has become more popular for delivering drugs to the brain. This method offers direct transport through neuronal pathways. The lipid-based nanocarriers like nanostructured lipid carriers (NLC) appear more favorable than other nanosystems for brain administration. The nanostructured lipid carriers (NLC) system can quickly transform into a gelling system to facilitate easy administration into the nasal passages. The various compatibility studies showed that the other lipid structured-based formulations may not work well for various reasons, including a low drug filing capacity; during storage, the formulation showed changes in the solid lipid structures, which gives a chance of medication ejection. Formulations containing NLC can minimize these problems by improving drug solubility and permeation rate by incorporating a ratio of liquid lipids with solid lipids, resulting in improved stability during storage and drug bioavailability because of the higher drug loading capacity. This review aimed to find and emphasize research on lipid-based nanocarrier formulations that have advanced the treatment of central nervous system illnesses using nasal passages to reach the targeted area's drug molecules.

Nose-to-brain delivery of lithium via a sprayable in situ-forming hydrogel composed of chelating starch nanoparticles

While bipolar disorder patients can benefit from lithium therapy, high levels of lithium in the serum can induce undesirable systemic side effects. Intranasal (IN) lithium delivery offers a potential solution to this challenge given its potential to facilitate improved lithium transport to brain when delivered to the olfactory mucosa. Herein, a sprayable, in situ forming nanoparticle network hydrogel (NNH) based on Schiff base interactions between chelator-functionalized oxidized starch nanoparticles (SNPs) and carboxymethyl chitosan (CMCh) is reported that can be deployed within the nasal cavity to release ultra-small penetrative SNPs over time. Chelating functional groups including citrate, ethylenediaminetetraacetic acid, and pentetic acid are shown to bind a variety of cations including lithium, magnesium, and calcium, with chelation directly linked to enhancements in the gel mechanics even for monovalent lithium. The hydrogels show high in vitro cytocompatibility with mouse striatal neuron and human primary nasal cell lines. Effective IN delivery of lithium to the brain is demonstrated for the first time, with both solution-based and hydrogel-loaded lithium showing in vivo efficacy in an amphetamine-induced pre-clinical rat bipolar manic phase model; specifically, IN-delivered NNHs can maintain successful attenuation of locomotor activity for up to 6 h while all other tested treatments (drug-only IN or conventional intraperitoneal delivery) failed to retain attenuation for more than two hours at the same lithium dose. As such, in situ-gelling and ion-chelating NNHs represent a new material that can effectively enable metal ion management in biomedical applications.

Advancement in the Nose-to-Brain Drug delivery of FDA-approved drugs for the better management of Depression and Psychiatric disorders

The Prevalence of Depressive and Psychiatric disorders is increasing globally, and despite the availability of numerous FDA-approved drugs, treatment remains challenging. Many conventional antidepressants and antipsychotic formulations face issues such as low solubility, high first-pass metabolism, poor bioavailability, inadequate blood-brain barrier penetration, and systemic side effects. These challenges lead to reduced efficacy, slower onset of action, and decreased patient adherence to treatment. To address these problems, recent studies have explored the nose-to-brain route for drug delivery. This method offers several advantages, including non-invasive drug administration, direct access to the brain, rapid onset of action, reduced systemic exposure and side effects, avoidance of first-pass metabolism, enhanced bioavailability, precision dosing, and improved patient compliance. The formulations used for this approach include lipidic nanoparticles, polymeric nanoparticles, nasal gels, cubosomes, niosomes, polymeric micelles, nanosuspensions, nanoemulsions, nanocapsules, and elastosomes. This review analyzes and summarizes the published work on the nose-to-brain delivery of FDA-approved antidepressants and antipsychotic drugs, with a focus on the preparation, characterization, pharmacokinetics, pharmacodynamics, and toxicity profiling of these nanoformulations.

The protective effects of gastrodin on neurological disorders: an update and future perspectives

Neurological disorders are characterized by high mortality and disability rates. Furthermore, the burden associated with disability and mortality resulting from neurological disorders has been increasing at an alarming rate. Botanical drugs and their bioactive components have emerged as a prominent area of research, offering a promising avenue for developing novel alternatives for treating neurological diseases. Gastrodin is the principal active component derived from the traditional Chinese medicinal plant Gastrodia elata Blume (GEB). Existing literature reveals that gastrodin exerts various pharmacological protective actions against neurological disorders. This review aimed to collate novel literature on gastrodin for treating neurological disorders from Web of Science, PubMed, Embase and CNKI. The pharmacokinetics of gastrodin, its therapeutic role in neurological disorders, the main mechanisms of action and clinical application were addressed. Furthermore, a detailed overview of gastrodin drug delivery systems and physical enhancement methods was presented, offering invaluable insights into potential research and the extensive applications of gastrodin.

Optically Controlled Drug Delivery Through Microscale Brain-Machine Interfaces Using Integrated Upconverting Nanoparticles

The aim of this work is to incorporate lanthanide-cored upconversion nanoparticles (UCNP) into the surface of microengineered biomedical implants to create a spatially controlled and optically releasable model drug delivery device in an integrated fashion. Our approach enables silicone-based microelectrocorticography (ECoG) implants holding platinum/iridium recording sites to serve as a stable host of UCNPs. Nanoparticles excitable in the near-infrared (lower energy) regime and emitting visible (higher energy) light are utilized in a study. With the upconverted higher energy photons, we demonstrate the induction of photochemical (cleaving) reactions that enable the local release of specific dyes as a model system near the implant. The modified ECoG electrodes can be implanted in brain tissue to act as an uncaging system that releases small amounts of substance while simultaneously measuring the evoked neural response upon light activation. In this paper, several technological challenges like the surface modification of UCNPs, the immobilization of particles on the implantable platform, and measuring the stability of integrated UCNPs in in vitro and in vivo conditions are addressed in detail. Besides the chemical, mechanical, and optical characterization of the ready-to-use devices, the effect of nanoparticles on the original electrophysiological function is also evaluated. The results confirm that silicone-based brain-machine interfaces can be efficiently complemented with UCNPs to facilitate local model drug release.

Glatiramer acetate in situ forming gel, a new approach for multiple sclerosis treatment

BACKGROUND

Glatiramer acetate (GA), a commonly used treatment for multiple sclerosis (MS), requires long-term frequent injections to ensure its effectiveness. This often leads to adverse effects, patient noncompliance, and economic inefficiency.

OBJECTIVES

In this study, poloxamer, as a thermosensitive polymer modified by chitosan (CS) and hyaluronic acid (HA), was employed to prepare an in situ forming prolonged release formulation of GA to overcome the problems derived from frequent repeated injections and to enhance the patient compliance.

METHODS

The sol-gel formulation was produced through a cold method and optimized using design of experiments. The final product was characterized in terms of gelation time (GT), rheological behaviors, morphological properties, assay, and drug release kinetics.

RESULTS

The in vitro release rate of GA during the first 24 h was quite rapid, but then it continued at a slower rate of 0.05 mg ml-1h-1. The in vivo analysis after the subcutaneous injections showed lower levels of IL-5, IL-13, and uric acid (UA) in mice treated with the gel formulation compared with those receiving free GA in the first few days. However, after 10 days, significantly higher concentrations were detected, which continued to increase slowly.

CONCLUSION

It can be concluded that the designed thermosensitive sol-gel formula is capable of extending the effectiveness of GA and can be considered as a promising sustained release formulation for the treatment of MS.

Nose to brain strategy coupled to nano vesicular system for natural products delivery: Focus on synaptic plasticity in Alzheimer's disease

A wide number of natural molecules demonstrated neuroprotective effects on synaptic plasticity defects induced by amyloid-β (Aβ) in ex vivo and in vivo Alzheimer's disease (AD) models, suggesting a possible use in the treatment of this neurodegenerative disorder. However, several compounds, administered parenterally and orally, are unable to reach the brain due to the presence of the blood-brain barrier (BBB) which prevents the passage of external substances, such as proteins, peptides, or phytocompounds, representing a limit to the development of treatment for neurodegenerative diseases, such as AD. The combination of nano vesicular systems, as colloidal systems, and nose to brain (NtB) delivery depicts a new nanotechnological strategy to overtake this limit and to develop new treatment approaches for brain diseases, including the use of natural molecules in combination therapy for AD. Herein, we will provide an updated overview, examining the literature of the last 20 years and using specific keywords that provide evidence on natural products with the ability to restore synaptic plasticity alterations in AD models, and the possible application using safe and non-invasive strategies focusing on nano vesicular systems for NtB delivery.

Innovative Approaches to Enhancing the Biomedical Properties of Liposomes

Liposomes represent a promising class of drug delivery systems that enhance the therapeutic efficacy and safety of various pharmaceutical agents. Also, they offer numerous advantages compared to traditional drug delivery methods, including targeted delivery to specific sites, controlled release, and fewer side effects. This review meticulously examines the methodologies employed in the preparation and characterization of liposomal formulations. With the rising incidence of adverse drug reactions, there is a pressing need for innovative delivery strategies that prioritize selectivity, specificity, and safety. Nanomedicine promises to revolutionize diagnostics and treatments, addressing current limitations and improving disease management, including cancer, which remains a major global health challenge. This paper aims to conduct a comprehensive study on the interest of biomedical research regarding nanotechnology and its implications for further applications.

Surface-modified liposomal in-situ nasal gel enhances brain targeting of berberine hydrochloride for Alzheimer's therapy: optimization and in vivo studies

This work aimed to formulate surface-modified berberine hydrochloride (BER)-loaded liposomes containing in-situ nasal gel for bran targeting. The liposomes were prepared by ethanol-injection method and optimized following a 32 full-factorial design. Size, morphology, zeta potential, ex-vivo permeation, and in-vitro release were estimated. The surface of optimized liposome was modified with ascorbic acid. The size of surface-modified liposomes was bigger (191.4 nm) than the unmodified liposomes (171 nm). Surface-modified liposomes were embedded in in-situ gel using poloxamer and Carbopol 934P. Liposomal in-situ gel showed higher permeation (71.94%) in contrast to the plain gel (46.64%). In-vivo pharmacokinetic examination of payload from liposomal in-situ gel displayed higher concentration in brain (Cmax of 93.50 ng/mL). The liposomal in-situ nasal gel had a higher drug targeting efficiency (138.43%) and a higher drug targeting potential (27.77%) confirming improved brain targeting. In male Wistar rats, the pharmacodynamic parameters (path length and escape latency) were evaluated with trimethyl tin-induced neurodegeneration. Animals treated with BER-loaded in-situ gel significantly decreased escape latency and path length in comparison to the control group. Histopathological assessment showed that the formulated gel was safe for intranasal administration. The developed formulation has the potential to effectively enhance the efficacy of BER in Alzheimer's disease management.

Mucoadhesive in situ nasal gel of amoxicillin trihydrate for improved local delivery: Ex vivo mucosal permeation and retention studies

Orally administered amoxicillin is recommended as the first-line treatment of acute bacterial rhinosinusitis (ABR) and given in a high-dose regimen. However, the risk of various systemic adverse reactions and low oral bioavailability are unbearable, increasing the threat of antibiotic resistance. Therefore, nasal delivery of amoxicillin can be a potential approach for effectively treating ABR locally, as well as overcoming those drawbacks. In a way to guarantee the effectiveness for local therapy in nasal cavity, the permeation and retention properties are of significant importance considerations. Accordingly, the present work aimed to investigate the characteristics with respect to the nasal applicability of the in situ gelling amoxicillin trihydrate (AMT) and further evaluate its permeability and retention properties through human nasal mucosa. The lyophilized formulations were characterized utilizing the Differential Scanning Calorimetry (DSC) and X-ray Powder Diffraction (XRPD), and also evaluated for its polarity, reconstitution time, droplet size distribution, mucoadhesive properties, and ex vivo permeability and retention studies. The results confirmed that the in situ gelling AMT formulations possess adequate mucoadhesive behavior, especially the formulation containing 0.3 % of gellan gum. Substantially, the in situ gelling AMT formulations were able to retain the drug on the surface of nasal mucosa instead of permeating across the membrane; thus, suitable for treating nasal infections locally. Altogether, the in situ gelling systems demonstrates promising abilities as a delivery platform to enhance local application of AMT within the nasal cavity.

Solubilization techniques used for poorly water-soluble drugs

About 40% of approved drugs and nearly 90% of drug candidates are poorly water-soluble drugs. Low solubility reduces the drugability. Effectively improving the solubility and bioavailability of poorly water-soluble drugs is a critical issue that needs to be urgently addressed in drug development and application. This review briefly introduces the conventional solubilization techniques such as solubilizers, hydrotropes, cosolvents, prodrugs, salt modification, micronization, cyclodextrin inclusion, solid dispersions, and details the crystallization strategies, ionic liquids, and polymer-based, lipid-based, and inorganic-based carriers in improving solubility and bioavailability. Some of the most commonly used approved carrier materials for solubilization techniques are presented. Several approved poorly water-soluble drugs using solubilization techniques are summarized. Furthermore, this review summarizes the solubilization mechanism of each solubilization technique, reviews the latest research advances and challenges, and evaluates the potential for clinical translation. This review could guide the selection of a solubilization approach, dosage form, and administration route for poorly water-soluble drugs. Moreover, we discuss several promising solubilization techniques attracting increasing attention worldwide.

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.

Non-Invasive Techniques of Nose to Brain Delivery Using Nanoparticulate Carriers: Hopes and Hurdles

Intranasal drug delivery route has emerged as a promising non-invasive method of administering drugs directly to the brain, bypassing the blood-brain barrier (BBB) and blood-cerebrospinal fluid barriers (BCSF). BBB and BCSF prevent many therapeutic molecules from entering the brain. Intranasal drug delivery can transport drugs from the nasal mucosa to the brain, to treat a variety of Central nervous system (CNS) diseases. Intranasal drug delivery provides advantages over invasive drug delivery techniques such as intrathecal or intraparenchymal which can cause infection. Many strategies, including nanocarriers liposomes, solid-lipid NPs, nano-emulsion, nanostructured lipid carriers, dendrimers, exosomes, metal NPs, nano micelles, and quantum dots, are effective in nose-to-brain drug transport. However, the biggest obstacles to the nose-to-brain delivery of drugs include mucociliary clearance, poor drug retention, enzymatic degradation, poor permeability, bioavailability, and naso-mucosal toxicity. The current review aims to compile current approaches for drug delivery to the CNS via the nose, focusing on nanotherapeutics and nasal devices. Along with a brief overview of the related pathways or mechanisms, it also covers the advantages of nasal drug delivery as a potential method of drug administration. It also offers several possibilities to improve drug penetration across the nasal barrier. This article overviews various in-vitro, ex-vivo, and in-vivo techniques to assess drug transport from the nasal epithelium into the brain.

Sources and Methods for the Production of Xyloglucan, a Promising Stimulus-Sensitive Biopolymer: A Review

Xyloglucan is a highly promising 'green' polymer that has found its application in the food and pharmaceutical industries. Due to its molecular structure similarity to mucin, it has remarkable mucoadhesion properties, which has led to a high research interest in this excipient for the development of transmucosal delivery systems. Thermosensitivity is another promising property of xyloglucan derivatives, which is mainly exhibited by synthetic block copolymers such as pluronics and PLGA derivatives. Delivery systems whose mechanism of active ingredient release is based on temperature sensitivity are widely used in many medical fields, ranging from antitumour therapy to intranasal delivery. Thus, conducting research on the possibility of obtaining and using a new mucoadhesive, fully biocompatible and affordable polymer-xyloglucan-is a promising task.

Octa-Arginine-Conjugated Liposomal Nimodipine Incorporated in a Temperature-Responsive Gel for Nasoencephalic Delivery

Nimodipine is the primary clinical drug used to treat cerebral vasospasm following subarachnoid hemorrhage. Currently, tablets have low bioavailability when taken orally, and injections contain ethanol. Therefore, we investigated a new method of nimodipine administration, namely, nasoencephalic administration. Nasal administration of nimodipine was carried out by attaching the cell-penetrating peptide octa-arginine (R8) to liposomes of nimodipine and incorporating it into a temperature-sensitive in situ gel. The prepared liposomes and gels underwent separate evaluations for in vitro characterization. In vitro release exhibited a significant slow-release effect. In vitro toad maxillary cilia model, RPMI 2650 cytotoxicity, and in vivo SD rat pathological histotoxicity experiments showed that all the dosage from the groups had no significant toxicity to toad maxillary cilia, RPMI 2650 cells, and SD rat tissues and organs, and the cilia continued to oscillate up to 694 ± 10.15 min, with the survival rate of the cells being above 85%. A transwell nasal mucosa cell model and an isolated porcine nasal mucosa model were established, and the results showed that the osmolality of the R8-modified nimodipine liposomal gel to nasal mucosal cells and isolated porcine nasal mucosa was 30.41 ± 2.14 and 65.9 ± 7.34 μg/mL, respectively, which was significantly higher than that of the NM-Solution and PEGylated nimodipine liposome gel groups. Animal fluorescence imaging studies revealed that the R8-modified nimodipine liposomal gel displayed increased brain fluorescence intensity compared to the normal liposomal gel. Pharmacokinetic results showed that after transnasal administration, the AUC(0-∞) of the R8-modified nimodipine liposomal gel was 11.662 ± 1.97 μg·mL-1, which was significantly higher than that of the plain nimodipine liposomal gel (5.499 ± 2.89 μg·mL-1). Brain-targeting experiments showed that the brain-targeting efficiencies of the PEGylated nimodipine liposome gel and R8-modified PEGylated nimodipine liposome gels were 20.44 and 33.45, respectively, suggesting that R8/PEG/Lip-NM-TSG significantly increased the brain-targeting of the drug.

Research Progress on the Strategies for Crossing the Blood-Brain Barrier

Recently, the incidence of brain diseases, such as central nervous system degenerative diseases, brain tumors, and cerebrovascular diseases, has increased. However, the blood-brain barrier (BBB) limits the effective delivery of drugs to brain disease areas. Therefore, the mainstream direction of new drug development for these diseases is to engineer drugs that can better cross the BBB to exert their effects in the brain. This paper reviews the research progress and application of the main trans-BBB drug delivery strategies (receptor/transporter-mediated BBB crossing, focused ultrasound to open the BBB, adenosine agonist reversible opening of the BBB, aromatic resuscitation, transnasal administration, cell-mediated trans-BBB crossing, and viral vector system-mediated brain drug delivery). Meanwhile, the potential applications, advantages, and disadvantages of these strategies for crossing the BBB are analyzed. Finally, the future development prospects of strategies for crossing the BBB are also discussed. These strategies have potential value for treating brain diseases.

A thermosensitive chitosan hydrogel: An attempt for the nasal delivery of dimethyl fumarate

Dimethyl fumarate (DMF) is a drug that is orally administered for the treatment of relapsing-remitting multiple sclerosis. However, DMF causes gastrointestinal side effects and flushing in 43 % of patients, which significantly contributes to treatment discontinuation. To reduce side effects and increase patient compliance, the aim of this study was to develop a thermosensitive chitosan/glycerophosphate hydrogel for the nasal administration of DMF. A binary system of DMF with hydroxypropyl-β-cyclodextrin (HP-β-CD) was made and included in the hydrogel precursor solution. The precursor solution (drug content, DMF stability, thermogelling properties, viscosity), and the resulting thermosensitive hydrogel (mucoadhesion, in vitro DMF permeation) were characterized. HP-β-CD was able to interact with DMF and improve its water solubility. The leader thermosensitive nasal solution, G1 solution, was loaded with approximately 92 % DMF, which remained stable for 21 days. The G1 solution formed a hydrogel in approximately 2-1 min; it had a pH of 6.8 ± 0.06 and caused no significant change in the osmolality of the simulated nasal medium. The G1 hydrogel showed good mucoadhesive properties and released DMF that permeated in vitro in a controlled manner. As a result, G1 is a potential new approach to exploit the intranasal administration of DMF for treating multiple sclerosis.

In situ-gelling hydrophobized starch nanoparticle-based nanoparticle network hydrogels for the effective delivery of intranasal olanzapine to treat brain disorders

Intranasal (IN) delivery offers potential to deliver antipsychotic drugs with improved efficacy to the brain. However, the solubilization of such drugs and the frequency of required re-application both represent challenges to its practical implementation in treating various mental illnesses including schizophrenia. Herein, we report a sprayable nanoparticle network hydrogel (NNH) consisting of hydrophobically-modified starch nanoparticles (SNPs) and mucoadhesive chitosan oligosaccharide lactate (COL) that can gel in situ within the nasal cavity and release ultra-small penetrative SNPs over time. Hydrophobization of the SNPs enables enhanced uptake and prolonged release of poorly water soluble drugs such as olanzapine from the NNH depot through mucous and ultimately into the brain via the nose-to-brain (N2B) pathway. The hydrogel shows high in vitro cytocompatibility in mouse striatal neuron and human primary nasal cell lines and in vivo efficacy in an amphetamine-induced pre-clinical rat schizophrenia model, with IN-delivered NNH hydrogels maintaining successful attenuation of locomotor activity for up to 4 h while all other tested treatments (drug-only IN or conventional intraperitoneal delivery) failed to attenuate at any time point past 0.5 h. As such, in situ-gelling NNHs represent a safe excipient for the IN delivery of hydrophobic drugs directly to the brain using customized SNPs that exhibit high penetration and drug complexing properties to maximize effective drug delivery.

Development of an Intranasal In Situ System for Ribavirin Delivery: In Vitro and In Vivo Evaluation

Recently, ribavirin has demonstrated effectiveness in treating glioblastoma through intranasal administration utilizing the nose-to-brain delivery route. Enhancing ribavirin's bioavailability can be achieved by utilizing intranasal stimuli-responsive systems that create a gel on the nasal mucosa. The research examined thermosensitive, pH-sensitive, and ion-selective polymers in various combinations and concentrations, chosen in line with the current Quality by Design (QbD) approach in pharmaceutical development. Following a thorough assessment of key parameters, the optimal composition of gellan gum at 0.5%, Poloxamer 124 at 2%, and purified water with ribavirin concentration at 100 mg/mL was formulated and subjected to in vivo testing. Through experiments on male rats, the nose-to-brain penetration mechanism of the active pharmaceutical ingredient (API) was elucidated, showcasing drug accumulation in the olfactory bulbs and brain.

Halofuginone-guided nano-local therapy: Nano-thermosensitive hydrogels for postoperative metastatic canine mammary carcinoma with scar removal

In female dogs, the highest morbidity and mortality rates cancer are the result of mammary adenocarcinoma, which presents with metastases in the lung. Other than early surgical removal, however, no special methods are available to treat mammary adenocarcinoma. Because human breast cancer and canine mammary carcinoma share clinical characteristics and heterogeneity, the canine model is a suitable spontaneous tumor model for breast cancer in humans. In this study, the physical swelling method was used to prepare halofuginone-loaded D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) polymer micelles nano-thermosensitive hydrogels (HTPM-gel). Furthermore, HTPM-gel was investigated via characterization, morphology, properties such as swelling experiment and in vitro release with reflecting its splendid nature. Moreover, HTPM-gel was further examined its capability to anti-proliferation, anti-migration, and anti-invasion. Ultimately, HTPM-gel was investigated for its in vivo anticancer activity in the post-operative metastatic and angiogenic canine mammary carcinoma. HTPM-gel presented spherical under transmission electron microscope (TEM) and represented grid structure under scanning electron microscope (SEM), with hydrodynamic diameter (HD) of 20.25 ± 2.5 nm and zeta potential (ZP) of 15.10 ± 1.82 mV. Additionally, HTPM-gel own excellent properties comprised of pH-dependent swelling behavior, sustained release behavior. To impede the migration, invasion, and proliferation of CMT-U27 cells, we tested the efficacy of HTPM-gel. Evaluation of in vivo anti-tumor efficacy demonstrates HTPM-gel exhibit a splendid anti-metastasis and anti-angiogenic ability, with exhibiting ideal biocompatibility. Notably, HTPM-gel also inhibited the scar formation in the healing process after surgery. In summary, HTPM-gel exhibited anti-metastasis and anti-angiogenic and scar repair features. According to the results of this study, HTPM-gel has encouraging clinical potential to treat tumors with multifunctional hydrogel.

Enhanced Stability and Solidification of Volatile Eugenol by Cyclodextrin-Metal Organic Framework for Nasal Powder Delivery

Eugenol (Eug) holds potential as a treatment for bacterial rhinosinusitis by nasal powder drug delivery. To stabilization and solidification of volatile Eug, herein, nasal inhalable γ-cyclodextrin metal-organic framework (γ-CD-MOF) was investigated as a carrier by gas-solid adsorption method. The results showed that the particle size of Eug loaded by γ-CD-MOF (Eug@γ-CD-MOF) distributed in the range of 10-150 μm well. In comparison to γ-CD and β-CD-MOF, γ-CD-MOF has higher thermal stability to Eug. And the intermolecular interactions between Eug and the carriers were verified by characterizations and molecular docking. Based on the bionic human nasal cavity model, Eug@γ-CD-MOF had a high deposition distribution (90.07 ± 1.58%). Compared with free Eug, the retention time Eug@γ-CD-MOF in the nasal cavity was prolonged from 5 min to 60 min. In addition, the cell viability showed that Eug@γ-CD-MOF (Eug content range 3.125-200 µg/mL) was non-cytotoxic. And the encapsulation of γ-CD-MOF could not reduce the bacteriostatic effect of Eug. Therefore, the biocompatible γ-CD-MOF could be a potential and valuable carrier for nasal drug delivery to realize solidification and nasal therapeutic effects of volatile oils.

Customized Intranasal Hydrogel Delivering Methylene Blue Ameliorates Cognitive Dysfunction against Alzheimer's Disease

The accumulation of hyperphosphorylated tau protein aggregates is a key pathogenic event in Alzheimer's disease (AD) and induces mitochondrial dysfunction and reactive oxygen species overproduction. However, the treatment of AD remains challenging owning to the hindrance caused by the blood-brain barrier (BBB) and the complex pathology of AD. Nasal delivery represents an effective means of circumventing the BBB and delivering drugs to the brain. In this study, black phosphorus (BP) is used as a drug carrier, as well as an antioxidant, and loaded with a tau aggregation inhibitor, methylene blue (MB), to obtain BP-MB. For intranasal (IN) delivery, a thermosensitive hydrogel is fabricated by cross-linking carboxymethyl chitosan and aldehyde Pluronic F127 (F127-CHO) micelles. The BP-MB nanocomposite is incorporated into the hydrogel to obtain BP-MB@Gel. BP-MB@Gel could be injected intranasally, providing high nasal mucosal retention and controlled drug release. After IN administration, BP-MB is continuously released and delivered to the brain, exerting synergistic therapeutic effects by suppressing tau neuropathology, restoring mitochondrial function, and alleviating neuroinflammation, thus inducing cognitive improvements in mouse models of AD. These findings highlight a potential strategy for brain-targeted drug delivery in the management of the complex pathologies of AD.

Essential considerations towards development of effective nasal antibiotic formulation: features, strategies, and future directions

INTRODUCTION

Intranasal antibiotic products are gaining popularity as a promising method of administering antibiotics, which provide numerous benefits, e.g. enhancing drug bioavailability, reducing adverse effects, and potentially minimizing resistance threats. However, some issues related to the antibiotic substances and nasal route challenges must be addressed to prepare effective formulations.

AREAS COVERED

This review focuses on the valuable points of nasal delivery as an alternative route for administering antibiotics, coupled with the challenges in the nasal cavity that might affect the formulations. Moreover, this review also highlights the application of nasal delivery to introduce antibiotics for local therapy, brain targeting, and systemic effects that have been conducted. In addition, this viewpoint provides strategies to maintain antibiotic stability and several crucial aspects to be considered for enabling effective nasal formulation.

EXPERT OPINION

In-depth knowledge and understanding regarding various key considerations with respect to the antibiotic substances and nasal route delivery requirement in preparing effective nasal antibiotic formulation would greatly improve the development of nasally administered antibiotic products, enabling better therapeutic outcomes of antibiotic treatment and establishing appropriate use of antibiotics, which in turn might reduce the chance of antibiotic resistance and enhance patient comfort.

Nanomedicines for intranasal delivery: understanding the nano-bio interactions at the nasal mucus-mucosal barrier

INTRODUCTION

Intranasal administration is an effective drug delivery routes in modern pharmaceutics. However, unlike other in vivo biological barriers, the nasal mucosal barrier is characterized by high turnover and selective permeability, hindering the diffusion of both particulate drug delivery systems and drug molecules. The in vivo fate of administrated nanomedicines is often significantly affected by nano-biointeractions.

AREAS COVERED

The biological barriers that nanomedicines encounter when administered intranasally are introduced, with a discussion on the factors influencing the interaction between nanomedicines and the mucus layer/mucosal barriers. General design strategies for nanomedicines administered via the nasal route are further proposed. Furthermore, the most common methods to investigate the characteristics and the interactions of nanomedicines when in presence of the mucus layer/mucosal barrier are briefly summarized.

EXPERT OPINION

Detailed investigation of nanomedicine-mucus/mucosal interactions and exploration of their mechanisms provide solutions for designing better intranasal nanomedicines. Designing and applying nanomedicines with mucus interaction properties or non-mucosal interactions should be customized according to the therapeutic need, considering the target of the drug, i.e. brain, lung or nose. Then how to improve the precise targeting efficiency of nanomedicines becomes a difficult task for further research.

In-situ gel: A smart carrier for drug delivery

In-situ gel technology is a promising drug delivery strategy that undergoes a 'sol to gel' transition upon administration, providing controlled and prolonged drug release. These gels are composed of cross-linked 3D networks of polymers, with hydrogels being a specific type of absorbing water while retaining their shape. Gelation can be triggered by various stimuli, such as temperature, pH, ions, and light. They offer several advantages like improved patient compliance, extended drug residence time, localized drug delivery, etc, but also have some disadvantages like drug degradation and limited mechanical strength. In-situ gel falls into three categories: temperature-sensitive, ion-sensitive, and pH-sensitive, but multi-responsive gels that respond to multiple stimuli have better drug release characteristics. The mechanism of in-situ gel formation involves physical and chemical mechanisms. There are various applications of in-situ gel, like ocular drug delivery, nose-to-brain delivery, etc. In this review, we have discussed the types, and mechanisms of in-situ gel & use of in-situ gel in the treatment of different diseases through various routes like buccal, vaginal, ocular, nasal, etc., along with its use in targeted drug delivery.

Recent progresses in natural based therapeutic materials for Alzheimer's disease

Alzheimer's disease is a neurological disorder that causes increased memory loss, mood swings, behavioral disorders, and disruptions in daily activities. Polymer scaffolds for the brain have been grown under laboratory, physiological, and pathological circumstances because of the limitations of conventional treatments for patients with central nervous system diseases. The blood-brain barrier prevents medications from entering the brain, challenging AD treatment. Numerous biomaterials such as biomolecules, polymers, inorganic metals, and metal oxide nanoparticles have been used to transport therapeutic medicines into the nervous system. Incorporating biocompatible materials that support neurogenesis through a combination of topographical, pharmacological, and mechanical stimuli has also shown promise for the transfer of cells to replenish dopaminergic neurons. Components made of naturally occurring biodegradable polymers are appropriate for the regeneration of nerve tissue. The ability of natural-based materials (biomaterials) has been shown to promote endogenous cell development after implantation. Also, strategic functionalization of polymeric nanocarriers could be employed for treating AD. In particular, nanoparticles could resolve Aβ aggregation and thus help cure Alzheimer's disease. Drug moieties can be effectively directed to the brain by utilizing nano-based systems and diverse colloidal carriers, including hydrogels and biodegradable scaffolds. Notably, early investigations employing neural stem cells have yielded promising results, further emphasizing the potential advancements in this field. Few studies have fully leveraged the combination of cells with cutting-edge biomaterials. This study provides a comprehensive overview of prior research, highlighting the pivotal role of biomaterials as sophisticated drug carriers. It delves into various intelligent drug delivery systems, encompassing pH and thermo-triggered mechanisms, polymeric and lipid carriers, inorganic nanoparticles, and other vectors. The discussion synthesizes existing knowledge and underscores the transformative impact of these biomaterials in devising innovative strategies, augmenting current therapeutic methodologies, and shaping new paradigms in the realm of Alzheimer's disease treatment.

Advances in peptide-based drug delivery systems

Drug delivery systems (DDSs) are designed to deliver drugs to their specific targets to minimize their toxic effects and improve their susceptibility to clearance during targeted transport. Peptides have high affinity, low immunogenicity, simple amino acid composition, and adjustable molecular size; therefore, most peptides can be coupled to drugs via linkers to form peptide-drug conjugates (PDCs) and act as active pro-drugs. PDCs are widely thought to be promising DDSs, given their ability to improve drug bio-compatibility and physiological stability. Peptide-based DDSs are often used to deliver therapeutic substances such as anti-cancer drugs and nucleic acid-based drugs, which not only slow the degradation rate of drugs in vivo but also ensure the drug concentration at the targeted site and prolong the half-life of drugs in vivo. This article provides an profile of the advancements and future development in functional peptide-based DDSs both domestically and internationally in recent years, in the expectation of achieving targeted drug delivery incorporating functional peptides and taking full advantage of synergistic effects.

Recent Advances in Intranasal Administration for Brain-Targeting Delivery: A Comprehensive Review of Lipid-Based Nanoparticles and Stimuli-Responsive Gel Formulations

Addressing disorders related to the central nervous system (CNS) remains a complex challenge because of the presence of the blood-brain barrier (BBB), which restricts the entry of external substances into the brain tissue. Consequently, finding ways to overcome the limited therapeutic effect imposed by the BBB has become a central goal in advancing delivery systems targeted to the brain. In this context, the intranasal route has emerged as a promising solution for delivering treatments directly from the nose to the brain through the olfactory and trigeminal nerve pathways and thus, bypassing the BBB. The use of lipid-based nanoparticles, including nano/microemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers, has shown promise in enhancing the efficiency of nose-to-brain delivery. These nanoparticles facilitate drug absorption from the nasal membrane. Additionally, the in situ gel (ISG) system has gained attention owing to its ability to extend the retention time of administered formulations within the nasal cavity. When combined with lipid-based nanoparticles, the ISG system creates a synergistic effect, further enhancing the overall effectiveness of brain-targeted delivery strategies. This comprehensive review provides a thorough investigation of intranasal administration. It delves into the strengths and limitations of this specific delivery route by considering the anatomical complexities and influential factors that play a role during dosing. Furthermore, this study introduces strategic approaches for incorporating nanoparticles and ISG delivery within the framework of intranasal applications. Finally, the review provides recent information on approved products and the clinical trial status of products related to intranasal administration, along with the inclusion of quality-by-design-related insights.

Quercetin-Loaded Nanostructured Lipid Carrier In Situ Gel for Brain Targeting Through Intranasal Route: Formulation, In Vivo Pharmacokinetic and Pharmacodynamic Studies

Quercetin (QT) shows potential for protecting against neurodegenerative diseases like Alzheimer's. However, its limited bioavailability and instability in physiological pH hinder its clinical use. The purpose of this work is to construct QT-filled nanostructured lipid carriers (QT-NLC) intranasal in situ gel to enhance pharmacokinetic and pharmacodynamic performance. NLCs were developed using a melt emulsification-high-pressure homogenization and were optimized using design expert software with the Box-Behnken design. NLCs were then incorporated into an in situ gel based on Lutrol F127 and further characterized. The pharmacodynamics of the formulation was evaluated in neurodegeneration induced by trimethyl tin (TMT) Wistar rats. The optimized QT in situ gel had spherical shape, entrapment efficiency of 96.1 ± 4.40%, and in vitro drug release of 83.74 ± 1.40%. The mean particle size was 123.3 ± 5.46 nm. After intranasal administration, in vivo single-dose pharmacokinetic studies demonstrated a significant therapeutic concentration of drug in CNS, having Cmax 183.41 ± 11.76 ng/mL and Tmax of 2 h. The more brain targeting efficiency of NLCs was proved by the developed QT in situ gel, which had a higher drug targeting efficiency (DTE) of 117.47% and drug targeting potential (DTP) of 88.9%. As compared to the neurodegeneration control group, the QT in situ gel-treated group had significantly decreased escape latency and pathlength. Biochemical analysis and histological investigations demonstrated that QT in situ gel exhibited superior anti-Alzheimer's potential compared to standard drug, donepezil. The promising results of the developed and optimized intranasal QT in situ gel suggest its potential and can be used in Alzheimer's disease management.

Facile fabrication of diatomite biosilica-based nasal drug delivery vehicle for enhanced treatment of allergic rhinitis

Nanostructured silica-based materials have great potential as drug delivery vehicles for precise and personalized medical applications. As natural nanostructured silica, diatomite biosilica (DB) is recognized as a novel carrier to construct oral/parenteral smart drug delivery systems due to high surface area, biocompatibility, and applicability at low cost, yet the related studies on its use in local delivery routes are still scarce. Herein, we proposed a novel strategy to develop multifunctional nasal drug delivery vehicles based on DB, and demonstrated their versatile performance for enhanced treatment of allergic rhinitis (AR). As a proof of concept, the purified DB microparticles were loaded with budesonide as an anti-inflammatory model drug, and further processed via surface modification to graft polydopamine and carboxymethyl chitosan layers. The synthesized microcapsules exhibited remarkable mucin binding capacity and antibacterial activity against Staphylococcus aureus. Besides, toxicity evaluation with human skin fibroblast cells and hemolysis tests indicated their high biocompatibility. Moreover, in vitro drug release results demonstrated pH-responsive release performance of the microcapsules under simulated AR environment (pH 5.0, 35 °C). Hence, this study provides a facile and reliable approach to construct DB-based mucoadhesive nasal drug delivery vehicles, showing great potential for treatment of allergic airway inflammatory diseases.

Preparation and characterization of a nanohydroxyapatite and sodium fluoride loaded chitosan-based in situ forming gel for enamel biomineralization

The development of remineralizing smart biomaterials is a contemporary approach to caries prevention. The present study aimed at formulation preparation and characterization of a thermoresponsive oral gel based on poloxamer and chitosan loaded with sodium fluoride (NaF) and nanohydroxyapatite (nHA) to treat demineralization. The chemical structure and morphology of the formulation were characterized using FTIR and FESEM-EDS tests. Hydrogel texture, rheology, and stability were also examined. The hydrogel was in a sol state at room temperature and became gel after being placed at 37 °C with no significance different in gelation time with the formulation without nHA and NaF as observed by t-test. The FTIR spectrum of nHA/NaF/chitosan-based hydrogel indicated the formation of physical crosslinking without any chemical interactions between the hydrogel components. The FESEM-EDS results demonstrated the uniform distribution of each element within the hydrogel matrix, confirming the successful incorporation of nHA and NaF in the prepared gel. The hardness, hydrogel's adhesiveness, and cohesiveness were 0.9 mJ, 1.7 mJ, and 0.37, respectively, indicating gel stability and the acceptable retention time of hydrogels. The formulation exhibited a non-Newtonian shear-thinning pseudoplastic and thixotropic behavior with absolute physical stability. Within the limitation of in vitro studies, nHA/NaF/chitosan-based in situ forming gel demonstrated favorable properties, which could be trasnsorm into a gel state in oral cavity due to poloxamer and chitosan and can prevent dental caries due to nHA and NaF. We propose this formulation as a promising dental material in tooth surface remineralization.

Post-exposure intranasal IFNα suppresses replication and neuroinvasion of Venezuelan Equine Encephalitis virus within olfactory sensory neurons

BACKGROUND

Venezuelan Equine Encephalitis virus (VEEV) may enter the central nervous system (CNS) within olfactory sensory neurons (OSN) that originate in the nasal cavity after intranasal exposure. While it is known that VEEV has evolved several mechanisms to inhibit type I interferon (IFN) signaling within infected cells, whether this inhibits virologic control during neuroinvasion along OSN has not been studied.

METHODS

We utilized an established murine model of intranasal infection with VEEV and a repository of scRNAseq data from IFN-treated OSN to assess the cellular targets and IFN signaling responses after VEEV exposure.

RESULTS

We found that immature OSN, which express higher levels of the VEEV receptor LDLRAD3 than mature OSN, are the first cells infected by VEEV. Despite rapid VEEV neuroinvasion after intranasal exposure, olfactory neuroepithelium (ONE) and olfactory bulb (OB) IFN responses, as assessed by evaluation of expression of interferon signaling genes (ISG), are delayed for up to 48 h during VEEV neuroinvasion, representing a potential therapeutic window. Indeed, a single intranasal dose of recombinant IFNα triggers early ISG expression in both the nasal cavity and OB. When administered at the time of or early after infection, IFNα treatment delayed onset of sequelae associated with encephalitis and extended survival by several days. VEEV replication after IFN treatment was also transiently suppressed in the ONE, which inhibited subsequent invasion into the CNS.

CONCLUSIONS

Our results demonstrate a critical and promising first evaluation of intranasal IFNα for the treatment of human encephalitic alphavirus exposures.

Research progress in brain-targeted nasal drug delivery

The unique anatomical and physiological connections between the nasal cavity and brain provide a pathway for bypassing the blood-brain barrier to allow for direct brain-targeted drug delivery through nasal administration. There are several advantages of nasal administration compared with other routes; for example, the first-pass effect that leads to the metabolism of orally administered drugs can be bypassed, and the poor compliance associated with injections can be minimized. Nasal administration can also help maximize brain-targeted drug delivery, allowing for high pharmacological activity at lower drug dosages, thereby minimizing the likelihood of adverse effects and providing a highly promising drug delivery pathway for the treatment of central nervous system diseases. The aim of this review article was to briefly describe the physiological structures of the nasal cavity and brain, the pathways through which drugs can enter the brain through the nose, the factors affecting brain-targeted nasal drug delivery, methods to improve brain-targeted nasal drug delivery systems through the application of related biomaterials, common experimental methods used in intranasal drug delivery research, and the current limitations of such approaches, providing a solid foundation for further in-depth research on intranasal brain-targeted drug delivery systems (see Graphical Abstract).

The prescription design and key properties of nasal gel for CNS drug delivery: A review

Central nervous system (CNS) diseases are among the major health problems. However, blood-brain barrier (BBB) makes traditional oral and intravenous delivery of CNS drugs inefficient. The unique direct connection between the nose and the brain makes nasal administration a great potential advantage in CNS drugs delivery. However, nasal mucociliary clearance (NMCC) limits the development of drug delivery systems. Appropriate nasal gel viscosity alleviates NMCC to a certain extent, gels based on gellan gum, chitosan, carbomer, cellulose and poloxamer have been widely reported. However, nasal gel formulation design and key properties for alleviating NMCC have not been clearly discussed. This article summarizes gel formulations of different polymers in existing nasal gel systems, and attempts to provide a basis for researchers to conduct in-depth research on the key characteristics of gel matrix against NMCC.

Nanoparticle-based Gene Therapy for Neurodegenerative Disorders

Neurological disorders present a formidable challenge in modern medicine due to the intricate obstacles set for the brain and the multipart nature of genetic interventions. This review article delves into the promising realm of nanoparticle-based gene therapy as an innovative approach to addressing the intricacies of neurological disorders. Nanoparticles (NPs) provide a multipurpose podium for the conveyance of therapeutic genes, offering unique properties such as precise targeting, enhanced stability, and the potential to bypass blood-brain barrier (BBB) restrictions. This comprehensive exploration reviews the current state of nanoparticle-mediated gene therapy in neurological disorders, highlighting recent advancements and breakthroughs. The discussion encompasses the synthesis of nanoparticles from various materials and their conjugation to therapeutic genes, emphasizing the flexibility in design that contributes to specific tissue targeting. The abstract also addresses the low immunogenicity of these nanoparticles and their stability in circulation, critical factors for successful gene delivery. While the potential of NP-based gene therapy for neurological disorders is vast, challenges and gaps in knowledge persist. The lack of extensive clinical trials leaves questions about safety and potential side effects unanswered. Therefore, this abstract emphasizes the need for further research to validate the therapeutic applications of NP-mediated gene therapy and to address nanosafety concerns. In conclusion, nanoparticle-based gene therapy emerges as a promising avenue in the pursuit of effective treatments for neurological disorders. This abstract advocates for continued research efforts to bridge existing knowledge gaps, unlocking the full potential of this innovative approach and paving the way for transformative solutions in the realm of neurological health.

Key Challenges, Influencing Factors, and Future Perspectives of Nanosuspensions in Enhancing Brain Drug Delivery

Many brain diseases pose serious challenges to human life. Alzheimer's Disease (AD) and Parkinson's Disease (PD) are common neurodegenerative diseases that seriously threaten human health. Glioma is a common malignant tumor. However, drugs cannot cross physiological and pathological barriers and most therapeutic drugs cannot enter the brain because of the presence of the Blood-brain Barrier (BBB) and Bloodbrain Tumor Barrier (BBTB). How to enable drugs to penetrate the BBB to enter the brain, reduce systemic toxicity, and penetrate BBTB to exert therapeutic effects has become a challenge. Nanosuspension can successfully formulate drugs that are difficult to dissolve in water and oil by using surfactants as stabilizers, which is suitable for the brain target delivery of class II and IV drugs in the Biopharmaceutical Classification System (BCS). In nanosuspension drug delivery systems, the physical properties of nanostructures have a great impact on the accumulation of drugs at the target site, such as the brain. Optimizing the physical parameters of the nanosuspension can improve the efficiency of brain drug delivery and disease treatment. Therefore, the key challenges, influencing factors, and future perspectives of nanosuspension in enhancing brain drug delivery are summarized and reviewed here. This article aims to provide a better understanding of nanosuspension formulation technology used for brain delivery and strategies used to overcome various physiological barriers.

Development and optimization of in-situ gel containing chitosan nanoparticles for possible nose-to-brain delivery of vinpocetine

Vinpocetine (VIN), a derivative of vincamine found in the vinca plant, widens blood vessels in the brain and has been shown to improve cognitive function, memory, and cerebrovascular disorders. Nevertheless, the clinical utility of VIN is constrained by factors such as low oral bioavailability owing to the first-pass metabolism that often demands frequent dosing of 3-4 tablets/day. In this regard, the present work aimed to develop VIN-loaded chitosan nanoparticles (VIN-CH-NPs) to surmount these limitations and in view to enhance delivery to the brain of VIN by minimizing systemic exposure. The chitosan (CH) nanoparticles (NP) were developed by ionotropic gelation technique employing tripolyphosphate (TPP) as a cross-linking agent. Employing Design of Experiments (DoE), the effect of CH and TPP concentrations and stirring speed were systematically optimized using Box Behnken design (BBD). The optimized batch of nanoparticles displayed a particle size, zeta potential, entrapment efficiency, and drug loading of 130.6 ± 8.38 nm, +40.81 ± 0.11 mV, 97.56 ± 0.04 %, and 61 ± 0.89 %, respectively. Fourier Transform Infrared Spectroscopy indicated the chemical integrity of the drug ruling out the interaction between the VIN and excipients used. DSC and PXRD data indicated that reduction of the crystallinity of VIN in the chitosan matrix. These VIN-CH-NPs manifested good stability, exhibiting an almost spherical morphology. To mitigate rapid mucociliary clearance upon intranasal administration, the optimized VIN-CH-NPs were incorporated into thermosensitive in situ gel (VIN-CHN-ISG). It was observed that the in-situ gel loaded with nanoparticles was opalescent with a pH level of 5.3 ± 0.38. It was also noted that the gelation temperature was 32 ± 0.89 °C, and the gelation time was approximately 15 s. The drug delivery to the brain through the nasal application of optimized VIN-NPs in situ gel was assessed in rats. The results indicated significant nasal application of the in-situ gel nearly doubled the Cmax (P < 0.05) and AUC0-t (P < 0.05) in the brain compared to oral administration. Nasal administration improved drug delivery to the brain by reducing systemic exposure to VIN. A histopathological study of the nasal mucosa revealed no irritation or toxicity, making it safe for nasal administration. These findings suggest that the developed NPs in-situ gel effectively targeted vinpocetine to the brain through the nasal pathway, providing a potential therapeutic strategy for managing Alzheimer's disease.

Intranasal Drug Delivery by Nanotechnology: Advances in and Challenges for Alzheimer's Disease Management

Alzheimer's disease, a progressive neurodegenerative condition, is characterized by a gradual decline in cognitive functions. Current treatment approaches primarily involve the administration of medications through oral, parenteral, and transdermal routes, aiming to improve cognitive function and alleviate symptoms. However, these treatments face limitations, such as low bioavailability and inadequate permeation. Alternative invasive methods, while explored, often entail discomfort and require specialized assistance. Therefore, the development of a non-invasive and efficient delivery system is crucial. Intranasal delivery has emerged as a potential solution, although it is constrained by the unique conditions of the nasal cavity. An innovative approach involves the use of nano-carriers based on nanotechnology for intranasal delivery. This strategy has the potential to overcome current limitations by providing enhanced bioavailability, improved permeation, effective traversal of the blood-brain barrier, extended retention within the body, and precise targeting of the brain. The comprehensive review focuses on the advancements in designing various types of nano-carriers, including polymeric nanoparticles, metal nanoparticles, lipid nanoparticles, liposomes, nanoemulsions, Quantum dots, and dendrimers. These nano-carriers are specifically tailored for the intranasal delivery of therapeutic agents aimed at combatting Alzheimer's disease. In summary, the development and utilization of intranasal delivery systems based on nanotechnology show significant potential in surmounting the constraints of current Alzheimer's disease treatment strategies. Nevertheless, it is essential to acknowledge regulatory as well as toxicity concerns associated with this route; meticulous consideration is required when engineering a carrier. This comprehensive review underscores the potential to revolutionize Alzheimer's disease management and highlights the importance of addressing regulatory considerations for safe and effective implementations. Embracing this strategy could lead to substantial advancements in the field of Alzheimer's disease treatment.

Intranasal mask for protecting the respiratory tract against viral aerosols

The spread of many infectious diseases relies on aerosol transmission to the respiratory tract. Here we design an intranasal mask comprising a positively-charged thermosensitive hydrogel and cell-derived micro-sized vesicles with a specific viral receptor. We show that the positively charged hydrogel intercepts negatively charged viral aerosols, while the viral receptor on vesicles mediates the entrapment of viruses for inactivation. We demonstrate that when displaying matched viral receptors, the intranasal masks protect the nasal cavity and lung of mice from either severe acute respiratory syndrome coronavirus 2 or influenza A virus. With computerized tomography images of human nasal cavity, we further conduct computational fluid dynamics simulation and three-dimensional printing of an anatomically accurate human nasal cavity, which is connected to human lung organoids to generate a human respiratory tract model. Both simulative and experimental results support the suitability of intranasal masks in humans, as the likelihood of viral respiratory infections induced by different variant strains is dramatically reduced.

In situ forming hydrogel loaded with predatory bacteria treats drug-resistant corneal infection

The development of potent bactericidal antibiotic alternatives is important to address the current antibiotic crisis. A representative example is the topical delivery of predatory Bdellovibrio bacteriovorus bacteria to treat ocular bacterial infection. However, the direct topical use of B. bacteriovorus suspensions has the problem of easy loss and inactivation. Here, a B. bacteriovorus in situ forming hydrogel (BIG) was constructed for the ocular delivery of B. bacteriovorus. BIGs, as a fluid in their primitive state, were temperature- and cation- dually sensitive, which was rapidly transformed into immobile gels in the ocular environment. BIGs not only kept the activity of B. bacteriovorus but also retained on the ocular surface for a long time. The biosafety of BIGs was good without HCEC cell toxicity and hemolysis. More importantly, BIGs highly inhibited the growth of drug-resistant Pseudomonas aeruginosa whether in vitro or in the infected rat eyes. The ocular infection was completely controlled by BIGs with no corneal ulcers and inflammations. This living bacteria gel is a promising medication for the local treatment of drug-resistant bacteria-induced ocular infection.

Quality by design for sumatriptan loaded nano-ethosomal mucoadhesive gel for the therapeutic management of nitroglycerin induced migraine

Migraine is a progressive neurological condition often accompanied by nausea and vomiting. Various drugs have recently been used in the treatment of migraine, including sumatriptan (SUT). However, SUT has poor pharmacological effects mainly due to its reduced permeability, blood brain barrier (BBB) effect, half-life and bioavailability. Herein, we developed SUT loaded nano-ethosomes (SUT-NEs) for intranasal (IN) delivery, after their incorporation into chitosan based mucoadhesive gel (SUT-NEsG). The observed mean particle size of SUT-NEs was 109.45 ± 4.03 nm with spherical morphology, mono dispersion (0.191 ± 0.001), negatively charged (-20.90 ± 1.98 mV) and with excellent entrapment efficiency (96.90 ± 1.85 %). Fourier-transform infrared (FTIR) spectra have depicted the compatibility of the components. Moreover, SUT-NEsG was homogeneous having suitable viscosity and mucoadhesive strength. In vitro release and ex vivo permeation analysis showed sustained release and improved permeation of the SUT-NEsG, respectively. Additionally, histopathological studies of nasal membrane affirmed the safety of SUT-NEsG after IN application. In vivo pharmacokinetic study demonstrated improved brain bioavailability of SUT-NEsG as compared to orally administered sumatriptan solution (SUT-SL). Furthermore, significantly enhanced pharmacological effect of SUT-NEsG was observed in behavioral and biochemical analysis, immunohistochemistry for NF-κB, and enzyme linked immuno assay (ELISA) for IL-1β and TNF-α in Nitroglycerin (NTG) induced migraine model. It can be concluded that migraine may be successfully managed through IN application of SUT-NEsG owing to the direct targeted delivery to the brain.

Stimuli-responsive nanoparticles delivered by a nasal-brain pathway alleviate depression-like behavior through extensively scavenging ROS

Depression is one of the most common mental diseases, which seriously affects patients' physical and mental health. Emerging evidence has indicated that oxidative stress (OS) is a major cause of neurodegeneration involved in the pathogenesis of depression. Consequently, targeted reactive oxygen species (ROS) elimination is regarded as a promising strategy for efficient depression therapy. In addition, insufficient brain drug delivery is the main obstacle to depression therapy owing to the presence of the blood-brain barrier (BBB). To achieve the goals of bypassing the BBB and promoting antioxidant therapy for depression, a broad-spectrum ROS scavenging NPs was rationally designed through a nasal-brain pathway developed for combined ROS scavenging and brain drug delivery. A hexa-arginine (R6) modified ROS-responsive dextran (DEX) derivate was synthesized for antidepressant olanzapine (Olz) and H2 donor amino borane (AB) loading to prepare Olz/RDPA nanoparticles (NPs). Subsequently, the NPs were dispersed into a thermoresponsive hydrogel system based on poloxamer. In vitro and in vivo results demonstrated that Olz/RDPA in situ thermoresponsive hydrogel system could effectively deliver NPs to the brain via the nasal-brain pathway and alleviate depression-like behaviors through combined ROS depletion and inhibition of 5-HT dysfunction of the oxidative stress-induced. The proposed ROS-scavenging nanotherapeutic would open a new window for depression treatment. STATEMENT OF SIGNIFICANCE: ROS is an innovative therapeutic target involving the pathology of depression whereas targeted delivery of ROS scavenging has not been achieved yet. In the current study, ROS-responsive nanoparticles (Olz/RDPA NPs) were prepared and dispersed in a thermosensitive hydrogel for delivery through the nasal-brain pathway for the treatment of depression. Sufficient ROS depletion and improvement of delivery capacity by the nasal-brain pathway effectively could reverse oxidative stress and alleviate depressive-like behavior. Collectively, these nanoparticles may represent a promising strategy for the treatment of depression.

Polysaccharide-Based Nanogels to Overcome Mucus, Skin, Cornea, and Blood-Brain Barriers: A Review

Nanocarriers have been extensively developed in the biomedical field to enhance the treatment of various diseases. However, to effectively deliver therapeutic agents to desired target tissues and enhance their pharmacological activity, these nanocarriers must overcome biological barriers, such as mucus gel, skin, cornea, and blood-brain barriers. Polysaccharides possess qualities such as excellent biocompatibility, biodegradability, unique biological properties, and good accessibility, making them ideal materials for constructing drug delivery carriers. Nanogels, as a novel drug delivery platform, consist of three-dimensional polymer networks at the nanoscale, offering a promising strategy for encapsulating different pharmaceutical agents, prolonging retention time, and enhancing penetration. These attractive properties offer great potential for the utilization of polysaccharide-based nanogels as drug delivery systems to overcome biological barriers. Hence, this review discusses the properties of various barriers and the associated constraints, followed by summarizing the most recent development of polysaccharide-based nanogels in drug delivery to overcome biological barriers. It is expected to provide inspiration and motivation for better design and development of polysaccharide-based drug delivery systems to enhance bioavailability and efficacy while minimizing side effects.

Novel Sprayable Thermosensitive Benzydamine Hydrogels for Topical Application: Development, Characterization, and In Vitro Biological Activities

Benzydamine hydrochloride (BZD) having analgesic, anesthetic, and anti-inflammatory effects is used orally or topically in the treatment of disorders such as joint inflammation and muscle pain. Within the scope of this study, sprayable thermosensitive BZD hydrogels were developed using thermoresponsive poloxamers to avoid systemic side effects and to provide better compliance for topical administration. Also, hydroxypropyl methyl cellulose (HPMC) was employed to improve the mechanical strength and bioadhesive properties of the hydrogel. The addition of BZD generally decreased the viscosity of the formulations (p < 0.05), while increasing the gelation temperature (p < 0.05). The formulations that did not have any clogs or leaks in the nozzle of the bottle during the spraying process were considered lead formulations. To spray the formulations easily, it was found that the viscosity at RT should be less than 200 mPa·s, and their gelation temperature should be between 26 and 34°C. Increasing HPMC and poloxamer improved bioadhesion. The amount of HPMC and poloxamers did not cause a significant change in the release characteristics of the formulations (p > 0.05); the release profiles of BZD from the formulations were similar according to model-independent kinetic (f2 > 50). HPMC and poloxamers had important roles in the accumulation of BZD in the skin. In vitro biological activity studies demonstrated that the formulations presented their anti-inflammatory activity with TNF-α inhibition but did not have any effect on the inhibition of COX enzymes as expected. As a result, thermosensitive hydrogels containing BZD might be an appropriate alternative, providing an advantage in terms of easier application compared to conventional gels.

Quality by design-based optimization of in situ ionic-sensitive gels of amoxicillin-loaded bovine serum albumin nanoparticles for enhanced local nasal delivery

A recommended first-line acute bacterial rhinosinusitis (ABR) treatment regimen includes a high dose of orally administered amoxicillin, despite its frequent systemic adverse reactions coupled with poor oral bioavailability. Therefore, to overcome these issues, nasal administration of amoxicillin might become a potential approach for treating ABR locally. The present study aimed to develop a suitable carrier system for improved local nasal delivery of amoxicillin employing the combination of albumin nanoparticles and gellan gum, an ionic-sensitive polymer, under the Quality by Design methodology framework. The application of albumin nanocarrier for local nasal antibiotic therapy means a novel approach by hindering the nasal absorption of the drug through embedding into an in situ gelling matrix, further prolonging the drug release in the nasal cavity. The developed formulations were characterized, including mucoadhesive properties, in vitro drug release and antibacterial activities. Based on the results, 0.3 % w/v gellan gum concentration was selected as the optimal in situ gelling matrix. Essentially, each formulation adequately inhibited the growth of five common nasal pathogens in ABR. In conclusion, the preparation of albumin-based nanoparticles integrated with in situ ionic-sensitive polymer provides promising ability as nanocarrier systems for delivering amoxicillin intranasally for local antibiotic therapy.