Intranasal delivery of nanoparticle encapsulated tarenflurbil: A potential brain targeting strategy for Alzheimer's disease

Nose-to-Brain Drug Delivery and Physico-Chemical Properties of Nanosystems: Analysis and Correlation Studies of Data from Scientific Literature

Background

In the last few decades, nose-to-brain delivery has been investigated as an alternative route to deliver molecules to the Central Nervous System (CNS), bypassing the Blood-Brain Barrier. The use of nanotechnological carriers to promote drug transfer via this route has been widely explored. The exact mechanisms of transport remain unclear because different pathways (systemic or axonal) may be involved. Despite the large number of studies in this field, various aspects still need to be addressed. For example, what physicochemical properties should a suitable carrier possess in order to achieve this goal? To determine the correlation between carrier features (eg, particle size and surface charge) and drug targeting efficiency percentage (DTE%) and direct transport percentage (DTP%), correlation studies were performed using machine learning.

Methods

Detailed analysis of the literature from 2010 to 2021 was performed on Pubmed in order to build "NANOSE" database. Regression analyses have been applied to exploit machine-learning technology.

Results

A total of 64 research articles were considered for building the NANOSE database (102 formulations). Particle-based formulations were characterized by an average size between 150-200 nm and presented a negative zeta potential (ZP) from -10 to -25 mV. The most general-purpose model for the regression of DTP/DTE values is represented by Decision Tree regression, followed by K-Nearest Neighbors Regressor (KNeighbor regression).

Conclusion

A literature review revealed that nose-to-brain delivery has been widely investigated in neurodegenerative diseases. Correlation studies between the physicochemical properties of nanosystems (mean size and ZP) and DTE/DTP parameters suggest that ZP may be more significant than particle size for DTP/DTE predictability.

Research Progress on the Pathogenesis, Diagnosis, and Drug Therapy of Alzheimer's Disease

As the population ages worldwide, Alzheimer's disease (AD), the most prevalent kind of neurodegenerative disorder among older people, has become a significant factor affecting quality of life, public health, and economies. However, the exact pathogenesis of Alzheimer's remains elusive, and existing highly recognized pathogenesis includes the amyloid cascade hypothesis, Tau neurofibrillary tangles hypothesis, and neuroinflammation hypothesis. The major diagnoses of Alzheimer's disease include neuroimaging positron emission computed tomography, magnetic resonance imaging, and cerebrospinal fluid molecular diagnosis. The therapy of Alzheimer's disease primarily relies on drugs, and the approved drugs on the market include acetylcholinesterase drugs, glutamate receptor antagonists, and amyloid-β monoclonal antibodies. Still, the existing drugs can only alleviate the symptoms of the disease and cannot completely reverse it. This review aims to summarize existing research results on Alzheimer's disease pathogenesis, diagnosis, and drug therapy, with the objective of facilitating future research in this area.

In-depth Mechanism, Challenges, and Opportunities of Delivering Therapeutics in Brain Using Intranasal Route

Central nervous system-related disorders have become a continuing threat to human life and the current statistic indicates an increasing trend of such disorders worldwide. The primary therapeutic challenge, despite the availability of therapies for these disorders, is to sustain the drug's effective concentration in the brain while limiting its accumulation in non-targeted areas. This is attributed to the presence of the blood-brain barrier and first-pass metabolism which limits the transportation of drugs to the brain irrespective of popular and conventional routes of drug administration. Therefore, there is a demand to practice alternative routes for predictable drug delivery using advanced drug delivery carriers to overcome the said obstacles. Recent research attracted attention to intranasal-to-brain drug delivery for promising targeting therapeutics in the brain. This review emphasizes the mechanisms to deliver therapeutics via different pathways for nose-to-brain drug delivery with recent advancements in delivery and formulation aspects. Concurrently, for the benefit of future studies, the difficulties in administering medications by intranasal pathway have also been highlighted.

Versatile Nanoparticulate Systems as a Prosperous Platform for Targeted Nose-Brain Drug Delivery

The intranasal route has proven to be a reliable and promising route for delivering therapeutics to the central nervous system (CNS), averting the blood-brain barrier (BBB) and avoiding extensive first-pass metabolism of some drugs, with minimal systemic exposure. This is considered to be the main problem associated with other routes of drug delivery such as oral, parenteral, and transdermal, among other administration methods. The intranasal route maximizes drug bioavailability, particularly those susceptible to enzymatic degradation such as peptides and proteins. This review will stipulate an overview of the intranasal route as a channel for drug delivery, including its benefits and drawbacks, as well as different mechanisms of CNS drug targeting using nanoparticulate drug delivery systems devices; it also focuses on pharmaceutical dosage forms such as drops, sprays, or gels via the nasal route comprising different polymers, absorption promoters, CNS ligands, and permeation enhancers.

A Cell-Based Nasal Model for Screening the Deposition, Biocompatibility, and Transport of Aerosolized PLGA Nanoparticles

The olfactory region of the nasal cavity directly links the brain to the external environment, presenting a potential direct route to the central nervous system (CNS). However, targeting drugs to the olfactory region is challenging and relies on a combination of drug formulation, delivery device, and administration technique to navigate human nasal anatomy. In addition, in vitro and in vivo models utilized to evaluate the performance of nasal formulations do not accurately reflect deposition and uptake in the human nasal cavity. The current study describes the development of a respirable poly(lactic-co-glycolic acid) nanoparticle (PLGA NP) formulation, delivered via a pressurized metered dose inhaler (pMDI), and a cell-containing three-dimensional (3D) human nasal cast model for deposition assessment of nasal formulations in the olfactory region. Fluorescent PLGA NPs (193 ± 3 nm by dynamic light scattering) were successfully formulated in an HFA134a-based pMDI and were collected intact following aerosolization. RPMI 2650 cells, widely employed as a nasal epithelial model, were grown at the air-liquid interface (ALI) for 14 days to develop a suitable barrier function prior to exposure to the aerosolized PLGA NPs in a glass deposition apparatus. Direct aerosol exposure was shown to have little effect on cell viability. Compared to an aqueous NP suspension, the transport rate of the aerosolized NPs across the RPMI 2650 barrier was higher at all time points indicating the potential advantages of delivery via aerosolization and the importance of employing ALI cellular models for testing respirable formulations. The PLGA NPs were then aerosolized into a 3D-printed human nasal cavity model with an insert of ALI RPMI 2650 cells positioned in the olfactory region. Cells remained highly viable, and there was significant deposition of the fluorescent NPs on the ALI cultures. This study is a proof of concept that pMDI delivery of NPs is a viable means of targeting the olfactory region for nose-to-brain drug delivery (NTBDD). The cell-based model allows not only maintenance under ALI culture conditions but also sampling from the basal chamber compartment; hence, this model could be adapted to assess drug deposition, uptake, and transport kinetics in parallel under real-life settings.

Navigating the Nose-to-Brain Route: A Systematic Review on Lipid-Based Nanocarriers for Central Nervous System Disorders

Background: The blood–brain barrier (BBB) regulates brain substance entry, posing challenges for treating brain diseases. Traditional methods face limitations, leading to the exploration of non-invasive intranasal drug delivery. This approach exploits the direct nose-to-brain connection, overcoming BBB restrictions. Intranasal delivery enhances drug bioavailability, reduces dosage, and minimizes systemic side effects. Notably, lipid nanoparticles, such as solid lipid nanoparticles and nanostructured lipid carriers, offer advantages like improved stability and controlled release. Their nanoscale size facilitates efficient drug loading, enhancing solubility and bioavailability. Tailored lipid compositions enable optimal drug release, which is crucial for chronic brain diseases. This review assesses lipid nanoparticles in treating neuro-oncological and neurodegenerative conditions, providing insights for effective nose-to-brain drug delivery. Methods: A systematic search was conducted across major medical databases (PubMed, Ovid MEDLINE, and Scopus) up to 6 January 2024. The search strategy utilized relevant Medical Subject Heading (MeSH) terms and keywords related to “lipid nanoparticles”, “intranasal administration”, “neuro-oncological diseases”, and “neurodegenerative disorders”. This review consists of studies in vitro, in vivo, or ex vivo on the intranasal administration of lipid-based nanocarriers for the treatment of brain diseases. Results: Out of the initial 891 papers identified, 26 articles met the eligibility criteria after a rigorous analysis. The exclusion of 360 articles was due to reasons such as irrelevance, non-reporting selected outcomes, the article being a systematic literature review or meta-analysis, and lack of method/results details. This systematic literature review, focusing on nose-to-brain drug delivery via lipid-based nanocarriers for neuro-oncological, neurodegenerative, and other brain diseases, encompassed 60 studies. A temporal distribution analysis indicated a peak in research interest between 2018 and 2020 (28.3%), with a steady increase over time. Regarding drug categories, Alzheimer’s disease was prominent (26.7%), followed by antiblastic drugs (25.0%). Among the 65 drugs investigated, Rivastigmine, Doxorubicin, and Carmustine were the most studied (5.0%), showcasing a diverse approach to neurological disorders. Notably, solid lipid nanoparticles (SLNs) were predominant (65.0%), followed by nanostructured lipid carriers (NLCs) (28.3%), highlighting their efficacy in intranasal drug delivery. Various lipids were employed, with glyceryl monostearate being prominent (20.0%), indicating preferences in formulation. Performance assessment assays were balanced, with in vivo studies taking precedence (43.3%), emphasizing the translation of findings to complex biological systems for potential clinical applications. Conclusions: This systematic review reveals the transformative potential of intranasal lipid nanoparticles in treating brain diseases, overcoming the BBB. Positive outcomes highlight the effectiveness of SLNs and NLCs, which are promising new approaches for ailments from AD to stroke and gliomas. While celebrating progress, addressing challenges like nanoparticle toxicity is also crucial.

Nanotechnology for enhanced nose-to-brain drug delivery in treating neurological diseases

Despite the increasing global incidence of brain disorders, achieving sufficient delivery towards the central nervous system (CNS) remains a formidable challenge in terms of translating into improved clinical outcomes. The brain is highly safeguarded by physiological barriers, primarily the blood-brain barrier (BBB), which routinely excludes most therapeutics from entering the brain following systemic administration. Among various strategies investigated to circumvent this challenge, intranasal administration, a noninvasive method that bypasses the BBB to allow direct access of drugs to the CNS, has been showing promising results. Nanotechnology-based drug delivery systems, in particular, have demonstrated remarkable capacities in overcoming the challenges posed by nose-to-brain drug delivery and facilitating targeted drug accumulation within the brain while minimizing side effects of systemic distribution. This review comprehensively summarizes the barriers of nose-to-brain drug delivery, aiming to enhance our understanding of potential physiological obstacles and improve the efficacy of nasal delivery in future trials. We then highlight cutting-edge nanotechnology-based studies that enhance nose-to-brain drug delivery in three key aspects, demonstrating substantial potential for improved treatment of brain diseases. Furthermore, the attention towards clinical studies will ease the regulatory approval process for nasal administration of nanomedicines targeting brain disease.

A new approach for the treatment of Alzheimer's disease: insulin-quantum dots

The potential use of insulin supplementation for Alzheimer's Disease (AD) was aimed to investigate and explore CQDs as an alternative delivery system. CQDs were produced by microwave and characterised. Insulin-loaded Ins-CQDs and in-situ Gel-Ins-CQDs were developed. The in vitro release kinetics, penetrations of insulin through excised sheep nasal mucosa were determined. Toxicity of CQDs were calculated on SH-SY5Y cells. The stability and usability of the prepared formulations were assessed. The insulin release from the solution was 70.75% after 3 hours, while it was 37.51% for in-situ Gel-Ins-CQDs. IC50 value was 52 µM. The mean particle diameters of Ins-CQDs and in-situ Gel-Ins-CQDs varied between 8.35 ± 0.19 to 8.75 ± 0.03 nm during a 6-month period. Zeta potentials ranged from -31.51 ± 1.39 to -24.43 ± 0.26 mV, and PDI values were between 9.8 ± 0.01 to 5.3 ± 3.2%(SD, n = 3) for Ins-CQDs and in-situ Gel-Ins-CQDs, respectively.Our results show that Gel-Ins-CQDs represented a controlled release over time and can be used for AD through the nasal route.

Study on the Nasal Drug Delivery System of NMD Liposomes In Situ Thermosensitive Gel

Nimodipine (NMD) is a 1,4-dihydropyridine calcium antagonist that is effective in the prevention and treatment of cerebral arterial vasospasm and cerebral ischemic injury caused by subarachnoid hemorrhage. Since the drug itself is highly insoluble in water and has low oral bioavailability, while injectable formulations may cause pain and inflammation, the blood-brain barrier (BBB) prevents the effective delivery of therapeutic agents to the brain tissue. Therefore, in the present study, NMD liposomes were prepared by ethanol injection and innovatively lyophilised and loaded into temperature-sensitive in situ gels for intranasal administration as sprays to deliver drugs to brain tissues bypassing the blood-brain barrier. The optimal gel formulation was obtained by screening in which liposomes were divided into lecithin, cholesterol, and NMD in the ratio of 40:10: 1; Pluronic P407, Pluronic P188, Tween 80, polyvinyl ketone and ethyl nipagin in the ratio of (180:20:3:1:1); Pluronic P407, Pluronic P188, Tween 80, polyvinyl ketone, and ethyl nipagin in the ratio of (180:20:3:1:1). The prepared flow gel can form a solidified gel after a temperature of 31.07-32.07°C and a time of 58.51-59.89 s. Meanwhile, the NMD liposome gel formulation achieved sustained release over 56 h. The pharmacokinetic results of the developed NMD liposomal temperature-sensitive in situ gel and NMD temperature-sensitive in situ gel showed that liposomal nasal mucosal in situ gel is a more effective brain-targeted drug delivery system for NMD.

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.

Antisense-oligonucleotide co-micelles with tumor targeting peptides elicit therapeutic effects by inhibiting microRNA-21 in the glioblastoma animal models

INTRODUCTION

miRNA-21 (miR-21) is highly expressed in glioblastoma, facilitating tumor growth by blocking the expression of apoptosis-related genes. Therefore, an antisense microRNA oligonucleotide (AMO) against miR-21 was suggested as a therapeutic nucleic acid for glioblastoma.

OBJECTIVES

AMO21 co-micelles were developed with tumor-targeting T7 peptides as an AMO21 delivery system by intranasal administration.

METHODS

Cholesterol-conjugated AMO21 (AMO21c) was mixed with cholesterol-conjugated T7 peptides (T7c) to produce tumor-targeted co-micelles. Physical characterization was performed by dynamic light scattering, gel retardation assay, scanning electron microscope and heparin competition assay. In vitro transfection efficiency to C6 glioblastoma cells was measured by flow cytometry. The AMO21c/T7c co-micelles were administered by intranasal instillation into the brain of intracranial glioblastoma rat models. Scrambled T7 (scrT7) and scrambled AMO21c (scrAMO21c) were used as a negative control. The therapeutic effects of the AMO21c/T7c co-micelles were evaluated by real time RT-PCR, immunohistochemistry, TUNEL assay, and Nissl staining.

RESULTS

The formation of the AMO21c/T7c co-micelles was confirmed in gel retardation and heparin competition assays. The highest delivery efficiency in vitro was achieved at a 1:10 wt ratio of AMO21c/T7c. The AMO21c/T7c co-micelles had higher delivery efficiency into C6 glioblastoma cells than naked AMO21c or AMO21c/lipofectamine complexes. After intranasal administration into the intracranial glioblastoma models, the delivery efficiency of the co-micelles into the brain was also higher than those of naked AMO21c and AMO21c/scrambled T7c. Thanks to their enhanced delivery efficiency, the AMO21c/T7c co-micelles downregulated miR-21, inducing the production of the pro-apoptotic phosphatase and tensin homolog (PTEN) and programmed cell death 4 (PDCD4) proteins in the tumor tissues. The tumor size was reduced by the AMO21c/T7c co-micelles more effectively than naked AMO21c, AMO21c/lipofectamine, or scrAMO21c/T7c treatment.

CONCLUSION

The results suggest that the co-micelles of AMO21c and T7c may be an efficient delivery system into a brain tumor through intranasal administration.

Designing lisuride intranasal nanocarrier system for reduction of oxidative damage with enhanced dopamine level in brain for Parkinsonism

In the present study, nanoemulsion (NE) loaded with lisuride were formulated for delivering drug to brain via intranasal route. Dopamine levels, pharmacokinetic, and antioxidant activity were estimated. Antioxidant effect of lisuride NE was assessed in-vivo using oxidative stress models revealing symptoms like those of Parkinson's disease. Intranasally administered lisuride NE-treated group revealed a greater number of antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione (GSH) as compared to the intravenously administered lisuride suspension in haloperidol rat model. Additionally, it was observed that lisuride NE can decrease dopamine loss. When lisuride NE was administered intranasally resulted in considerably higher dopamine concentrations (17.48 ± 0.05 ng/mL) in comparison to rats receiving haloperidol (7.28 ± 0.02 ng/mL). From study, it is suggested that NE is a possible strategy to deliver lisuride intranasally to lower free radical damage and prevent the biochemical alterations associated with Parkinson's disease.

A critical review on the role of nanotheranostics mediated approaches for targeting β amyloid in Alzheimer's

Alzheimer's is one of the most common neurodegenerative illnesses that affect brain cellular function. In this disease, the neurons in the brain are considered to be decaying steadily but consistently by the accumulation of amyloid mass, particularly the β-amyloids, amyloid proteins, and Tau proteins. The most responsible amyloid-proteins are amyloid-40 and amyloid-42, which have a high probability of accumulating in excess over the brain cell, interfering with normal brain cell function and triggering brain cell death. The advancement of pharmaceutical sciences leads to the development of Nanotheranostics technology, which may be used to diagnose and treat Alzheimer's. They are the colloidal nanoparticles functionalised with the therapeutic moiety as well as a diagnostic moiety. This article discusses the prognosis of Alzheimer's, various nanotheranostics approaches (nanoparticles, quantum dots, aptamers, dendrimers, etc), and their recent advancement in managing Alzheimer's. Also, various in-vitro and in-vivo diagnostic methodologies were discussed with respect to nanotheranostics.

Nose-to-brain drug delivery for the treatment of CNS disease: New development and strategies

Delivering drugs to the brain has always been a challenging task due to the restrictive properties of the blood-brain barrier (BBB). Intranasal delivery is therefore emerging as an efficient method of administration, making it easy to self-administration and thus provides a non-invasive and painless alternative to oral and parenteral administration for delivering therapeutics to the central nervous system (CNS). Recently, drug formulations have been developed to further enhance this nose-to-brain transport, primarily using nanoparticles (NPs). Therefore, the purposes of this review are to highlight and describe the anatomical basis of nasal-brain pathway and provide an overview of drug formulations and current drugs for intranasal administration in CNS disease.

Drug-Loaded Silver Nanoparticles-A Tool for Delivery of a Mebeverine Precursor in Inflammatory Bowel Diseases Treatment

Chronic, multifactorial illnesses of the gastrointestinal tract include inflammatory bowel diseases. One of the greatest methods for regulated medicine administration in a particular region of inflammation is the nanoparticle system. Silver nanoparticles (Ag NPs) have been utilized as drug delivery systems in the pharmaceutical industry. The goal of the current study is to synthesize drug-loaded Ag NPs using a previously described 3-methyl-1-phenylbutan-2-amine, as a mebeverine precursor (MP). Methods: A green, galactose-assisted method for the rapid synthesis and stabilization of Ag NPs as a drug-delivery system is presented. Galactose was used as a reducing and capping agent forming a thin layer encasing the nanoparticles. Results: The structure, size distribution, zeta potential, surface charge, and the role of the capping agent of drug-loaded Ag NPs were discussed. The drug release of the MP-loaded Ag NPs was also investigated. The Ag NPs indicated a very good drug release between 80 and 85%. Based on the preliminary results, Ag NPs might be a promising medication delivery system for MP and a useful treatment option for inflammatory bowel disease. Therefore, future research into the potential medical applications of the produced Ag NPs is necessary.

Formulation of antiretroviral nanocrystals and development into a microneedle delivery system for potential treatment of HIV-associated neurocognitive disorder (HAND)

HIV/AIDS remains a major global public health issue. While antiretroviral therapy is effective at reducing the viral load in the blood, up to 50% of those with HIV suffer from some degree of HIV-associated neurocognitive disorder, due to the presence of the blood-brain barrier restricting drugs from crossing into the central nervous system and treating the viral reservoir there. One way to circumvent this is the nose-to-brain pathway. This pathway can also be accessed via a facial intradermal injection. Certain parameters can increase delivery via this route, including using nanoparticles with a positive zeta potential and an effective diameter of 200 nm or less. Microneedle arrays offer a minimally invasive, pain-free alternative to traditional hypodermic injections. This study shows the formulation of nanocrystals of both rilpivirine (RPV) and cabotegravir, followed by incorporation into separate microneedle delivery systems for application to either side of the face. Following an in vivo study in rats, delivery to the brain was seen for both drugs. For RPV, a C_max was seen at 21 days of 619.17 ± 73.32 ng/g, above that of recognised plasma IC90 levels, and potentially therapeutically relevant levels were maintained for 28 days. For CAB, a C_max was seen at 28 days of 478.31 ± 320.86 ng/g, and while below recognised 4IC90 levels, does indicate that therapeutically relevant levels could be achieved by manipulating final microaaray patch size in humans.

Thin film hydration versus modified spraying technique to fabricate intranasal spanlastic nanovesicles for rasagiline mesylate brain delivery: Characterization, statistical optimization, and in vivo pharmacokinetic evaluation

Rasagiline mesylate (RM) is a monoamine oxidase inhibitor that is commonly used to alleviate the symptoms of Parkinson's disease. However, it suffers from low oral bioavailability due to its extensive hepatic metabolism in addition to its hydrophilic nature which limits its ability to pass through the blood-brain barrier (BBB) and reach the central nervous system where it exerts its pharmacological effect. Thus, this study aims to form RM-loaded spanlastic vesicles for intranasal (IN) administration to overcome its hepatic metabolism and permit its direct delivery to the brain. RM-loaded spanlastics were prepared using thin film hydration (TFH) and modified spraying technique (MST). A 2³ factorial design was constructed to study and optimize the effects of the independent formulation variables, namely, Span type, Span: Brij 35 ratio, and sonication time on the vesicles᾽ characteristics in each preparation technique. The optimized system prepared using MST (MST 2) has shown higher desirability factor with smaller PS and higher EE%; thus, it was selected for further in vivo evaluation where it revealed that the extent of RM distribution from the intranasally administered spanlastics to the brain was comparable to that of the IV drug solution with significantly high brain-targeting efficiency (458.47%). These results suggest that the IN administration of the optimized RM-loaded spanlastics could be a promising, non-invasive alternative for the efficient delivery of RM to brain tissues to exert its pharmacological activities without being dissipated to other body organs which subsequently may result in higher pharmacological efficiency and better safety profile.

An emerging era in manufacturing of drug delivery systems: Nanofabrication techniques

Nanotechnology has the capability of making significant contributions to healthcare. Nanofabrication of multifunctional nano- or micro-character systems is becoming incredibly influential in various sectors like electronics, photonics, energy, and biomedical gadgets worldwide. The invention of such items led to the merger of moderate cost and excellent quality nano or micro-characters into 3D structures. Nanofabrication techniques have many benefits as the primary technology for manipulating cellular surroundings to research signaling processes. The inherent nanoscale mechanisms of cyto-reactions include the existence and death of cells, stem cell segmentation, multiplication, cellular relocation, etc. Nanofabrication is essential in developing various nano-formulations like solid lipid nanoparticles, nanostructured lipid carriers, liposomes, niosomes, nanoemulsions, microemulsions etc. Despite the initial development cost in designing the nanofabrication-based products, it has also reduced the total cost of the healthcare system by considering the added benefits compared to the other standard formulations. Thus, the current review mainly focuses on nanofabrication techniques, advantages, disadvantages, applications in developing various nanocarrier systems, challenges and future perspectives.

Investigating the Targeting Power to Brain Tissues of Intranasal Rasagiline Mesylate-Loaded Transferosomal In Situ Gel for Efficient Treatment of Parkinson's Disease

Rasagiline mesylate (RSM) is a hydrophilic drug with poor oral bioavailability (36%) because of hepatic first-pass metabolism. The present study focuses on delivering RSM directly to the brain through its inclusion within transferosomal in situ gel administered through the intranasal (IN) route. Transferosomes were formed by the thin-film hydration method with the aid of Design-Expert^® software by varying the edge activator (EA) type in the absence or presence of cholesterol. By desirability calculations, the optimum formulation was composed of phosphatidylcholine and sodium deoxycholate as an EA (5:1% w/w) with no cholesterol. The optimum formulation was 198.63 ± 34.98 nm in size and displayed an entrapment efficiency of 95.73 ± 0.09%. Transmission electron microscopy revealed discrete and spherical vesicles. Optimized transferosomes were further incorporated into an in situ gel composed of 0.5% pectin, 15% Pluronic^® F-127, and 5% Pluronic^® F-68 and tested for the in vivo performance. The systemic as well as brain kinetics were assessed in rats by comparing the IN-administered in situ gel to the IV aqueous solution. The optimum in situ gel showed safety and biocompatibility on rats' nasal mucosa with enhanced brain bioavailability (131.17%). Drug targeting efficiency and direct transport percentage indices (304.53% and 67.16%, respectively) supported successful brain targeting offering direct nose-to-brain drug delivery.

Optimization and Appraisal of Chitosan-Grafted PLGA Nanoparticles for Boosting Pharmacokinetic and Pharmacodynamic Effect of Duloxetine HCl Using Box-Benkhen Design

Duloxetine HCl (DXH) is a psychiatric medicine employed for treating major depressive disorder. Nonetheless, its low water solubility, high first-pass metabolism, and acid instability diminish the absolute oral bioavailability to 40%, thus necessitating frequent administration. Therefore, the aim of the current study was to formulate DXH as nasal chitosan-grafted polymeric nanoparticles to improve its pharmacokinetic and pharmacodynamic properties. Applying the Box-Behnken design, DXH loaded PLGA-Chitosan nanoparticles (DXH-PLGA-CS-NPs) were fabricated and optimized using polylactide-co-glycolic acid (PLGA), chitosan (CS), and polyvinyl alcohol (PVA) as the independent factors. Particle size, entrapment efficiency, release percent, and cumulative amount permeated after 24 h of DXH-PLGA-CS-NPs (dependent variables) were evaluated. The in-vivo biodistribution and pharmacodynamic studies were done in male Wistar rats. The optimized DXH-PLGA-CS-NPs had a vesicle size of 122.11 nm and EE% of 66.95 with 77.65% release and Q₂₄ of 555.34 (µg/cm²). Ex-vivo permeation study revealed 4-folds increase in DXH permeation from DXH-PLGA-CS-NPs after 24 h compared to DXH solution. Intranasal administration of optimized DXH-PLGA-CS-NPs resulted in significantly higher (p < 0.05) C_max, AUC_total, t_1/2, and MRT in rat brain and plasma than oral DXH solution. Pharmacodynamics investigation revealed that intranasally exploited optimal DXH-PLGA-CS-NPs could be deemed a fruitful horizon for DXH as a treatment for depression.

Current and Future Nano-Carrier-Based Approaches in the Treatment of Alzheimer's Disease

It is a very alarming situation for the globe because 55 million humans are estimated to be affected by Alzheimer's disease (AD) worldwide, and still it is increasing at the rapid speed of 10 million cases per year worldwide. This is an urgent reminder for better research and treatment due to the unavailability of a permanent medication for neurodegenerative disorders like AD. The lack of drugs for neurodegenerative disorder treatment is due to the complexity of the structure of the brain, mainly due to blood-brain barrier, because blood-brain drug molecules must enter the brain compartment. There are several novel and conventional formulation approaches that can be employed for the transportation of drug molecules to the target site in the brain, such as oral, intravenous, gene delivery, surgically implanted intraventricular catheter, nasal and liposomal hydrogels, and repurposing old drugs. A drug's lipophilicity influences metabolic activity in addition to membrane permeability because lipophilic substances have a higher affinity for metabolic enzymes. As a result, the higher a drug's lipophilicity is, the higher its permeability and metabolic clearance. AD is currently incurable, and the medicines available merely cure the symptoms or slow the illness's progression. In the next 20 years, the World Health Organization (WHO) predicts that neurodegenerative illnesses affecting motor function will become the second-leading cause of mortality. The current article provides a brief overview of recent advances in brain drug delivery for AD therapy.

Dendrimers in Neurodegenerative Diseases

Neurodegenerative diseases (NDs), such as Parkinson’s Disease (PD), Alzheimer’s Disease (AD), Multiple Sclerosis (MS) and amyotrophic lateral sclerosis (ALS), are characterized by progressive loss of structure or function of neurons. Current therapies for NDs are only symptomatic and long-term ineffective. This challenge has promoted the development of new therapies against relevant targets in these pathologies. In this review, we will focus on the most promising therapeutic approaches based on dendrimers (DDs) specially designed for the treatment and diagnosis of NDs. DDs are well-defined polymeric structures that provide a multifunctional platform for developing different nanosystems for a myriad of applications. DDs have been proposed as interesting drug delivery systems with the ability to cross the blood–brain barrier (BBB) and increase the bioavailability of classical drugs in the brain, as well as genetic material, by reducing the synthesis of specific targets, as β-amyloid peptide. Moreover, DDs have been shown to be promising anti-amyloidogenic systems against amyloid-β peptide (Aβ) and Tau aggregation, powerful agents for blocking α-synuclein (α-syn) fibrillation, exhibit anti-inflammatory properties, promote cellular uptake to certain cell types, and are potential tools for ND diagnosis. In summary, DDs have emerged as promising alternatives to current ND therapies since they may limit the extent of damage and provide neuroprotection to the affected tissues.

Exploring the potential of intranasally administered naturally occurring quercetin loaded into polymeric nanocapsules as a novel platform for the treatment of anxiety

Anxiety is one of the most prevalent forms of psychopathology that affects millions worldwide. It gained more importance under the pandemic status that resulted in higher anxiety prevalence. Anxiolytic drugs such as benzodiazepines have an unfavorable risk/benefit ratio resulting in a shift toward active ingredients with better safety profile such as the naturally occurring quercetin (QRC). The delivery of QRC is hampered by its low water solubility and low bioavailability. The potential to enhance QRC delivery to the brain utilizing polymeric nanocapsules administered intranasally is investigated in the current study. Polymeric nanocapsules were prepared utilizing the nanoprecipitation technique. The best formula displayed a particle size of 227.8 ± 11.9 nm, polydispersity index of 0.466 ± 0.023, zeta potential of - 17.5 ± 0.01 mV, and encapsulation efficiency % of 92.5 ± 1.9%. In vitro release of QRC loaded polymeric nanocapsules exhibited a biphasic release with an initial burst release followed by a sustained release pattern. Behavioral testing demonstrated the superiority of QRC loaded polymeric nanocapsules administered intranasally compared to QRC dispersion administered both orally and intranasally. The prepared QRC loaded polymeric nanocapsules also demonstrated good safety profile with high tolerability.

Recent Updates on the Development of Therapeutics for the Targeted Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a complicated, multifaceted, irreversible, and incurable neurotoxic old age illness. Although NMDA (N-methyl D-aspartate)-receptor antagonists, cholinesterase repressors, and their pairings have been approved for the treatment, they are useful for short symptomatic relief. Researchers throughout the globe have been constantly working to uncover the therapy of Alzheimer's disease as new candidates must be determined, and newer treatment medicines must be developed. The aim of this review is to address recent advances in medication research along with new Alzheimer's disease therapy for diverse targets. Information was gathered utilizing a variety of internet resources as well as websites, such as ALZFORUM (alzforum.org) and clinicaltrials.gov. In contrast to other domains, the proposed medicines target amyloids (secretases, A42 generation, neuroinflammation, amyloid precipitation, and immunization), tau proteins (tau phosphorylation/aggregation and immunotherapy), and amyloid deposition. Despite tremendous advancement in our understanding of the underlying pathophysiology of Alzheimer's disease, the FDA (Food and Drug Administration) only approved aducanumab for diagnosis and treatment in 2003. Hence, novel treatment tactics are needed to find and develop therapeutic medicines to combat Alzheimer's disease.

Polymer drug conjugates containing memantine, tacrine and cinnamic acid: promising nanotherapeutics for the treatment of Alzheimer's disease

AIM

To prepare polymer-drug conjugates containing a combination of memantine, tacrine, and E)-N-(3-aminopropyl)cinnamide, promising therapeutics for the treatment of neurodegenerative disorders.

METHODS

The conjugates were characterised by ¹HNMR, particle size analysis, SEM, LC-MS, TEM/EDX, and XRD, followed by in vitro anti-acetylcholinesterase and drug release studies.

RESULTS

¹H NMR analysis revealed successful drug conjugation with drug mass percentages in the range of 1.3-6.0% w/w. The drug release from the conjugates was sustained for 10 h in the range of 20-36%. The conjugates' capability to inhibit acetylcholinesterase (AChE) activity was significant with IC₅₀ values in the range of 13-44.4 µm which was more effective than tacrine (IC₅₀ =1698.8 µm). The docking studies further confirmed that the conjugation of the drugs into the polymer improved their anti-acetylcholinesterase activity.

CONCLUSION

The drug release profile, particle sizes, and in vitro studies revealed that the conjugates are promising therapeutics for treating neurodegenerative disorders.

An update on the novel and approved drugs for Alzheimer disease

Introduction

Given the severity of the condition and the increasing number of patients, developing effective therapies for Alzheimer's disease has become a significant necessity. Aggregation of Amyloid-Beta (Aβ) plaques and Tau Protein Tangles in the brain's nerve tissue are two of the most histopathological/pathophysiological symptoms. Another important element involved in the etiology of Alzheimer's disease is the reduction in acetylcholine (ACh) levels in the brain. Currently available medications for Alzheimer's disease treatment, such as cholinesterase inhibitors and an antagonist of the N-methyl-d-aspartate receptor, can temporarily reduce dementia symptoms but not stop or reverse disease development. In addition, several medicinal plants have been shown to diminish the degenerative characteristics associated with Alzheimer's disease, either in its crude form or as isolated chemicals.

Aim

This review summarises the results from previous studies that reflect an array of novel therapies underway in various phases of clinical trials. Many are discontinued due to non-adherence to the designed endpoints or the surfacing of unavoidable side effects. The present piece of article focuses on the approved drugs for the treatment of Alzheimer's disease and their related mode of action as well as the promising therapies for the treatment of the said disease. Special attention has been placed on the researched herbal drugs, with the pipeline of novel therapies underway in various phases of clinical trials.

Result

The current article includes a list of approved pharmaceuticals for treating Alzheimer's disease, prospective therapies for the illness's treatment, and a pipeline of novel therapies in various stages of clinical trials.

Conclusion

The results suggest that the drugs under clinical trials may open new pathways for the effective treatment of patients with Alzheimer's disease while improving their quality of life.

Meta-Analysis: A Convenient Tool for the Choice of Nose-to-Brain Nanocarriers

OBJECTIVES

The intranasal route represents a high promising route of administration aiming for brain delivery. Yet, it represents one of the most difficult and complicated routes. Accordingly, scientists are in a continuous search for novel drug delivery vehicles such as the lipid and polymeric nanoparticles that are apt to enhance the bioavailability of the administered drugs to reach the brain. In this study, a certain number of publications were selected from different databases and literature. Meta-analysis studies using two different algorithms (DerSimonian-Laird and inverse variance) followed aiming to explore the published studies and confirm by evidence the superiority of nanocarriers in enhancing the brain bioavailability of various drugs. Furthermore, the quantitative comparison of lipid versus polymeric nanosystems was performed.

METHODS

The area under the curve (AUC) as an important pharmacokinetic parameter extracted from in vivo animal studies was designated as the "effect" in the performed meta-analysis after normalization. Forest plots were generated.

KEY FINDINGS AND CONCLUSIONS

The meta-analysis confirmed the augmentation of the AUC after the comparison with traditional preparations such as solutions and suspensions. Most importantly, lipid nanoparticles were proven to be significantly superior to the polymeric counterparts.

Biopolymer Nanoparticles for Nose-to-Brain Drug Delivery: A New Promising Approach for the Treatment of Neurological Diseases

Diseases affecting the central nervous system (CNS) are among the most disabling and the most difficult to cure due to the presence of the blood–brain barrier (BBB) which represents an impediment from a therapeutic and diagnostic point of view as it limits the entry of most drugs. The use of biocompatible polymer nanoparticles (NPs) as vehicles for targeted drug delivery to the brain arouses increasing interest. However, the route of administration of these vectors remains critical as the drug must be delivered without being degraded to achieve a therapeutic effect. An innovative approach for the administration of drugs to the brain using polymeric carriers is represented by the nose-to-brain (NtB) route which involves the administration of the therapeutic molecule through the neuro-olfactory epithelium of the nasal mucosa. Nasal administration is a non-invasive approach that allows the rapid transport of the drug directly to the brain and minimizes its systemic exposure. To date, many studies involve the use of polymer NPs for the NtB transport of drugs to the brain for the treatment of a whole series of disabling neurological diseases for which, as of today, there is no cure. In this review, various types of biodegradable polymer NPs for drug delivery to the brain through the NtB route are discussed and particular attention is devoted to the treatment of neurological diseases such as Glioblastoma and neurodegenerative diseases.

Therapeutic nanotechnologies for Alzheimer's disease: a critical analysis of recent trends and findings

Alzheimer's Disease (AD) is an irreversible neurodegenerative disease for which no disease modifying therapies are presently available. Besides the identification of pathological targets, AD presents numerous clinical and pharmacological challenges such as efficient active delivery to the central nervous system, cell targeting, and long-term dosing. Nanoparticles have been explored to overcome some of these challenges as drug delivery vehicles or drugs themselves. However, early promises have failed to materialize as no nanotechnology-based product has been able to reach the market and very few have moved past preclinical stages. In this review, we perform a critical analysis of the past decade's research on nanomedicine-based therapies for AD at the preclinical and clinical stages. The main obstacles to nanotechnology products and the most promising approaches were also identified, including renewed promise with gene editing, gene modulation, and vaccines.

Intranasal Delivery of Functionalized Polymeric Nanomaterials to the Brain

Intravenous delivery of nanomaterials containing therapeutic agents and various cargos for treating neurological disorders is often constrained by low delivery efficacy due to difficulties in passing the blood-brain barrier (BBB). Nanoparticles (NPs) administered intranasally can move along olfactory and trigeminal nerves so that they do not need to pass through the BBB, allowing non-invasive, direct access to selective neural pathways within the brain. Hence, intranasal (IN) administration of NPs can effectively deliver drugs and genes into targeted regions of the brain, holding potential for efficacious disease treatment in the central nervous system (CNS). In this review, current methods for delivering conjugated NPs to the brain are primarily discussed. Distinctive potential mechanisms of therapeutic nanocomposites delivered via IN pathways to the brain are then discussed. Recent progress in developing functional NPs for applications in multimodal bioimaging, drug delivery, diagnostics, and therapeutics is also reviewed. This review is then concluded by discussing existing challenges, new directions, and future perspectives in IN delivery of nanomaterials.

Therapeutic Approach to Alzheimer’s Disease: Current Treatments and New Perspectives

Alzheimer’s disease (AD) is the most common cause of dementia. The pathophysiology of this disease is characterized by the accumulation of amyloid-β, leading to the formation of senile plaques, and by the intracellular presence of neurofibrillary tangles based on hyperphosphorylated tau protein. In the therapeutic approach to AD, we can identify three important fronts: the approved drugs currently available for the treatment of the disease, which include aducanumab, donepezil, galantamine, rivastigmine, memantine, and a combination of memantine and donepezil; therapies under investigation that work mainly on Aβ pathology and tau pathology, and which include γ-secretase inhibitors, β-secretase inhibitors, α-secretase modulators, aggregation inhibitors, metal interfering drugs, drugs that enhance Aβ clearance, inhibitors of tau protein hyperphosphorylation, tau protein aggregation inhibitors, and drugs that promote the clearance of tau, and finally, other alternative therapies designed to improve lifestyle, thus contributing to the prevention of the disease. Therefore, the aim of this review was to analyze and describe current treatments and possible future alternatives in the therapeutic approach to AD.

Recent Advances in the Treatment of Alzheimer’s Disease Using Nanoparticle-Based Drug Delivery Systems

Alzheimer’s disease (AD) is an irreversible and progressive neurodegenerative disorder. Most existing treatments only provide symptomatic solutions. Here, we introduce currently available commercial drugs and new therapeutics, including repositioned drugs, to treat AD. Despite tremendous efforts, treatments targeting the hallmarks of AD show limited efficacy. Challenges in treating AD are partly caused by difficulties in penetrating the blood–brain barrier (BBB). Recently, nanoparticle (NP)-based systems have shown promising potential as precision medicines that can effectively penetrate the BBB and enhance the targeting ability of numerous drugs. Here, we describe how NPs enter the brain by crossing, avoiding, or disrupting the BBB. In addition, we provide an overview of the action of NPs in the microenvironment of the brain for the treatment of AD. Diverse systems, including liposomes, micelles, polymeric NPs, solid-lipid NPs, and inorganic NPs, have been investigated for NP drug loading to relieve AD symptoms, target AD hallmarks, and target moieties to diagnose AD. We also highlight NP-based immunotherapy, which has recently gained special attention as a potential treatment option to disrupt AD progression. Overall, this review focuses on recently investigated NP systems that represent innovative strategies to understand AD pathogenesis and suggests treatment and diagnostic modalities to cure AD.

Intranasal lipid nanocarriers: Uptake studies with fluorescently labeled formulations

Drug delivery by the intranasal route allows both systemic absorption and non-invasive brain targeting, due to the unique connection provided by the olfactory and trigeminal nerves between the brain and the external environment. Lipid nanocarriers can improve intranasal drug delivery by enhancing bioadhesion to nasal mucosa, and by protecting the encapsulated drug from biological degradation and transport efflux proteins. In this study two different biocompatible lipid nanocarriers were compared: nanoemulsions and solid lipid nanoparticles. The nasal uptake was investigated by labeling the nanocarriers lipid matrix with two fluorescent probes, 6-coumarin and rhodamine B, both lipophilic, yet characterized by different water solubility, in order to mimic the behavior of hypothetic drug compounds. Ex vivo permeation, in vivo pharmacokinetics and biodistribution studies were performed. 6-coumarin, water insoluble and therefore integral with the lipid matrix, was taken up to a limited extent, within a long timeframe, but with a proportionally more pronounced brain accumulation. In nanoemulsions soluble rhodamine B showed a relevant systemic uptake, with good bioavailability, likely due to the prompt release of the probe at the nasal mucosa.

Curcumin and Quercetin-Loaded Lipid Nanocarriers: Development of Omega-3 Mucoadhesive Nanoemulsions for Intranasal Administration

Curcumin (CUR) and quercetin (QU) are potential compounds for treatment of brain diseases such as neurodegenerative diseases (ND) because of their anti-inflammatory and antioxidant properties. However, low water solubility and poor bioavailability hinder their clinical use. In this context, nanotechnology arises as a strategy to overcome biopharmaceutical issues. In this work, we develop, characterize, compare, and optimize three different omega-3 (ω-3) fatty acids nanoemulsions (NEs) loaded with CUR and QU (negative, cationic, gelling) prepared by two different methods for administration by intranasal route (IN). The results showed that formulations prepared with the two proposed methods exhibited good stability and were able to incorporate a similar amount of CUR and QU. On the other side, differences in size, zeta potential, in vitro release kinetics, and permeation/retention test were observed. Considering the two preparation methods tested, high-pressure homogenization (HPH) shows advantages, and the CQ NE- obtained demonstrated potential for sustained release. Toxicity studies demonstrated that the formulations were not toxic for Caenorhabditis elegans. The developed ω-3 fatty acid NEs have shown a range of interesting properties for the treatment of brain diseases, since they have the potential to increase the nose-to-brain permeation of CUR and QU, enabling enhanced treatments efficiency.

Pharmacokinetics and Pharmacodynamics of Intranasal Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for Nose-to-Brain Delivery

Nose-to-brain drug delivery has been of great interest for the treatment of many central nervous system (CNS) diseases and psychiatric disorders over past decades. Several nasally administered formulations have been developed to circumvent the blood-brain barrier and directly deliver drugs to the CNS through the olfactory and trigeminal pathways. However, the nasal mucosa’s drug absorption is insufficient and the volume of the nasal cavity is small, which, in combination, make nose-to-brain drug delivery challenging. These problems could be minimized using formulations based on solid lipid nanoparticles (SLNs) or nanostructured lipid carriers (NLCs), which are effective nose-to-brain drug delivery systems that improve drug bioavailability by increasing drug solubility and permeation, extending drug action, and reducing enzymatic degradation. Various research groups have reported in vivo pharmacokinetics and pharmacodynamics of SLNs and NLCs nose-to-brain delivery systems. This review was undertaken to provide an overview of these studies and highlight research performed on SLN and NLC-based formulations aimed at improving the treatment of CNS diseases such neurodegenerative diseases, epilepsy, and schizophrenia. We discuss the efficacies and brain targeting efficiencies of these formulations based on considerations of their pharmacokinetic parameters and toxicities, point out some gaps in current knowledge, and propose future developmental targets.

Lipid-Based Nanocarriers via Nose-to-Brain Pathway for Central Nervous System Disorders

Neurodegenerative disorders are distinguished by the gradual deterioration of the nervous system's structure and function due to oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation. Among these NDs, Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis characterized an increasing dysfunction and loss of neuronal structure leading to neuronal cell death. Although there is currently no drug to totally reverse the effects of NDs, such novel formulations and administration routes are developed for better management and nose-to-brain delivery is one of delivery for treating NDs. This review aimed to highlight advances in research on various lipid based nanocarriers such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and cubosomes which are reported to treat and alleviate the symptoms of NDs via nose-to-brain route. The challenges during clinical translation of lipid nanocarriers from bench to bed side is also discussed.

Nanoparticles in Combating Neuronal Dysregulated Signaling Pathways: Recent Approaches to the Nanoformulations of Phytochemicals and Synthetic Drugs Against Neurodegenerative Diseases

As the worldwide average life expectancy has grown, the prevalence of age-related neurodegenerative diseases (NDDs) has risen dramatically. A progressive loss of neuronal function characterizes NDDs, usually followed by neuronal death. Inflammation, apoptosis, oxidative stress, and protein misfolding are critical dysregulated signaling pathways that mainly orchestrate neuronal damage from a mechanistic point. Furthermore, in afflicted families with genetic anomalies, mutations and multiplications of α-synuclein and amyloid-related genes produce some kinds of NDDs. Overproduction of such proteins, and their excessive aggregation, have been proven in various models of neuronal malfunction and death. In this line, providing multi-target therapies carried by novel delivery systems would pave the road to control NDDs through simultaneous modulation of such dysregulated pathways. Phytochemicals are multi-target therapeutic agents, which employ several mechanisms towards neuroprotection. Besides, the blood-brain barrier (BBB) is a critical issue in managing NDDs since it inhibits the accessibility of drugs to the brain in sufficient concentration. Besides, discovering novel delivery systems is vital to improving the efficacy, bioavailability, and pharmacokinetic of therapeutic agents. Such novel formulations are also employed to improve the drug's biodistribution, allow for the co-delivery of several medicines, and offer targeted intracellular delivery against NDDs. The present review proposes nanoformulations of phytochemicals and synthetic agents to combat NDDs by modulating neuroinflammation, neuroapoptosis, neuronal oxidative stress pathways and protein misfolding.

Alzheimer's Disease: Pathogenesis and Therapeutic Interventions

BACKGROUND

Alzheimer's Disease (AD) is the most common cause of dementia. Genetics, excessive exposure to environmental pollutants, as well as unhealthy lifestyle practices are often linked to the development of AD. No therapeutic approach has achieved complete success in treating AD; however, early detection and management with appropriate drugs are key to improving prognosis.

INTERVENTIONS

The pathogenesis of AD was extensively discussed in order to understand the reasons for the interventions suggested. The interventions reviewed include the use of different therapeutic agents and approaches, gene therapy, adherence to healthy dietary plans (Mediterranean diet, Okinawan diet and MIND diet), as well as the use of medicinal plants. The potential of nanotechnology as a multidisciplinary and interdisciplinary approach in the design of nano-formulations of AD drugs and the use of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as theranostic tools for early detection of Alzheimer's disease were also discussed.

Bone Marrow-Derived Mesenchymal Stem Cells (BMSCs)-Derived miR-200c Regulates Wingless-Related Integration Site (Wnt)/β-Catenin Signaling in Prostate Cancer by Targeting Cortactin (CTTN)

Bone marrow-derived mesenchymal stem cells (BMSCs) are an integral part of cancer microenvironment. We intend to clarify BMSC-derived exosomes’ role in prostate cancer. The exosomes miR-200c secreted by BMSCs were identified by electron microscopy. The mice tumor model was used to explore the role of miR-200c’s in tumor mice. Cell invasion was assessed by transwell assay and Wnt/β-catenin expression was measured by western blot. Exosomes miR-200c derived from BMSCs promoted tumor cell invasion and activated Wnt/β-catenin signaling. miR-200c targets CTTN-mediated cell signal transduction, and blocking CTTN expression can suppression miR-200c-mediated Wnt/β-catenin signal transduction and inhibit cell invasion. In conclusion, miR-200c regulates CTTN, thereby inducing Wnt/β-catenin signaling to enhance tumor growth.

Focused Ultrasound-Mediated Intranasal Brain Drug Delivery Technique (FUSIN)

The blood-brain barrier (BBB) is the major barrier for brain drug delivery and limits the treatment options for central nervous system diseases. To circumvent the BBB, we introduced the focused ultrasound-mediated intranasal brain drug delivery (FUSIN) technique. FUSIN utilizes the nasal route for direct nose-to-brain drug administration, bypassing the BBB and minimizing systemic exposure. It also uses the transcranial application of ultrasound energy focused at a targeted brain region to induce microbubble cavitation, which enhances the transport of intranasally administered agents at the FUS-targeted brain location. FUSIN is unique in that it can achieve noninvasive and localized brain drug delivery with minimized systemic toxicity. The goal of this chapter is to provide a detailed protocol for FUSIN delivery to the mouse brain.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. Reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are currently being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tend to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

Convolutions in the rendition of nose to brain therapeutics from bench to bedside: Feats & fallacies

Brain, a subtle organ of multifarious nature presents plethora of physiological, metabolic and bio-chemical convolutions that impede the delivery of biomolecules and thereby resulting in truncated therapeutic outcome in pathological conditions of central nervous system (CNS). The absolute bottleneck in the therapeutic management of such devastating CNS ailments is the BBB. Another pitfall is the lack of efficient technological platforms (due to high cost and low approval rates) as well as limited clinical trials (due to failures of neuro‑leads in late-stage pipelines) for CNS disorders which has become a literal brain drain with poorest success rates compared to other therapeutic areas, owing to time consuming processes, tremendous convolutions and conceivable adverse effects. With the advent of intranasal delivery (via direct N2B or indirect nose to blood to brain), several novel drug delivery carriers viz. unmodified or surface modified nanoparticle based carriers, lipid based colloidal nanocarriers and drysolid/liquid/semisolid nanoformulations or delivery platforms have been designed as a means to deliver therapeutic agents (small and large molecules, peptides and proteins, genes) to brain, bypassing BBB for disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, schizophrenia and CNS malignancies primarily glioblastomas. Intranasal application offers drug delivery through both direct and indirect pathways for the peripherally administered psychopharmacological agents to CNS. This route could also be exploited for the repurposing of conventional drugs for new therapeutic uses. The limited clinical translation of intranasal formulations has been primarily due to existence of barriers of mucociliary clearance in the nasal cavity, enzyme degradation and low permeability of the nasal epithelium. The present review literature aims to decipher the new paradigms of nano therapeutic systems employed for specific N2B drug delivery of CNS drugs through in silico complexation studies using rationally chosen mucoadhesive polymers (exhibiting unique physicochemical properties of nanocarrier's i.e. surface modification, prolonging retention time in the nasal cavity, improving penetration ability, and promoting brain specific delivery with biorecognitive ligands) via molecular docking simulations. Further, the review intends to delineate the feats and fallacies associated with N2B delivery approaches by understanding the physiological/anatomical considerations via decoding the intranasal drug delivery pathways or critical factors such as rationale and mechanism of excipients, affecting the permeability of CNS drugs through nasal mucosa as well as better efficacy in terms of brain targeting, brain bioavailability and time to reach the brain. Additionally, extensive emphasis has also been laid on the innovative formulations under preclinical investigation along with their assessment by means of in vitro /ex vivo/in vivo N2B models and current characterization techniques predisposing an efficient intranasal delivery of therapeutics. A critical appraisal of novel technologies, intranasal products or medical devices available commercially has also been presented. Finally, it could be warranted that more reminiscent pharmacokinetic/pharmacodynamic relationships or validated computational models are mandated to obtain effective screening of molecular architecture of drug-polymer-mucin complexes for clinical translation of N2B therapeutic systems from bench to bedside.

Nanotherapeutics for Nose-to-Brain Drug Delivery: An Approach to Bypass the Blood Brain Barrier

Treatment of neurodegenerative diseases or other central nervous system (CNS) disorders has always been a significant challenge. The nature of the blood-brain barrier (BBB) limits the penetration of therapeutic molecules to the brain after oral or parenteral administration, which, in combination with hepatic metabolism and drug elimination and inactivation during its journey in the systemic circulation, decreases the efficacy of the treatment, requires high drug doses and often induces adverse side effects. Nose-to-brain drug delivery allows the direct transport of therapeutic molecules by bypassing the BBB and increases drug concentration in the brain. The present review describes mechanisms of nose-to-brain drug delivery and discusses recent advances in this area with especial emphasis on nanotechnology-based approaches.

Nanoparticle-Guided Brain Drug Delivery: Expanding the Therapeutic Approach to Neurodegenerative Diseases

Neurodegenerative diseases (NDs) represent a heterogeneous group of aging-related disorders featured by progressive impairment of motor and/or cognitive functions, often accompanied by psychiatric disorders. NDs are denoted as 'protein misfolding' diseases or proteinopathies, and are classified according to their known genetic mechanisms and/or the main protein involved in disease onset and progression. Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD) are included under this nosographic umbrella, sharing histopathologically salient features, including deposition of insoluble proteins, activation of glial cells, loss of neuronal cells and synaptic connectivity. To date, there are no effective cures or disease-modifying therapies for these NDs. Several compounds have not shown efficacy in clinical trials, since they generally fail to cross the blood-brain barrier (BBB), a tightly packed layer of endothelial cells that greatly limits the brain internalization of endogenous substances. By engineering materials of a size usually within 1-100 nm, nanotechnology offers an alternative approach for promising and innovative therapeutic solutions in NDs. Nanoparticles can cross the BBB and release active molecules at target sites in the brain, minimizing side effects. This review focuses on the state-of-the-art of nanoengineered delivery systems for brain targeting in the treatment of AD, PD and HD.

Strategies for the delivery of antidiabetic drugs via intranasal route

Diabetes is a metabolic disorder defined by higher blood glucose levels in the body generally controlled by antidiabetic agents (oral) and insulin (subcutaneous). To avoid the limitations of the conventional routes such as lower bioavailability and pain at the site of injection in case of parenteral route modified delivery systems are proposed like transdermal, pulmonary and inhalation delivery and among the other delivery systems nasal drug delivery system that shows the advantages such as reduced frequency of dose, higher patient compliance, safety, ease of administration, prolonged residence time, improved absorption of drug in the body, higher bioavailability and stability. This review article discusses the strategies adopted for the delivery of antidiabetic drugs by the intranasal delivery system. The insulin and glucagon-like peptides on experimentation show results of improved therapeutic levels and patient compliance. The drugs are transported by the paracellular route and absorbed through the epithelial tight junctions successfully by utilising different strategies. The limitations of the nasal delivery such as irritation or burning on administration, degradation by the enzymes, mucociliary clearance, lesser volume of the nasal cavity and permeation through the nasal mucosa. To overcome the challenges different strategies for the nasal administration are studied such as polymers, particulate delivery systems, complexation with peptides and smart delivery using glucose-responsive systems. A vast scope of intranasal preparations exists for antidiabetic drugs in the future for the management of diabetes and more clinical studies are the requirement for the societal impact to battle against diabetes.

Nano-lipidic formulation and therapeutic strategies for Alzheimer's disease via intranasal route

AIM

The inability of drug molecules to cross the 'Blood-Brain Barrier' restrict the effective treatment of Alzheimer's disease. Lipid nanocarriers have proven to be a novel paradigm in brain targeting of bioactive by facilitating suitable therapeutic concentrations to be attained in the brain.

METHODS

The relevant information regarding the title of this review article was collected from the peer-reviewed published articles. Also, the physicochemical properties, and their in vitro and in vivo evaluations were presented in this review article.

RESULTS

Administration of lipid-based nano-carriers have abilities to target the brain, improve the pharmacokinetic and pharmacodynamics properties of drugs, and mitigate the side effects of encapsulated therapeutic active agents.

CONCLUSION

Unlike oral and other routes, the Intranasal route promises high bioavailability, low first-pass effect, better pharmacokinetic properties, bypass of the systemic circulation, fewer incidences of unwanted side effects, and direct delivery of anti-AD drugs to the brain via circumventing 'Blood-Brain Barrier'.