Liposomal Formulations for Nose-to-Brain Delivery: Recent Advances and Future Perspectives

Different Methods and Formulations of Drugs and Vaccines for Nasal Administration

Nasal drug delivery is advantageous when compared with other routes of drug delivery as it avoids the hepatic first-pass effect, blood–brain barrier penetration, and compliance issues with parenteral administration. However, nasal administration also has some limitations, such as its low bioavailability due to metabolism on the mucosal surface, and irreversible damage to the nasal mucosa due to the ingredients added into the formula. Moreover, the method of nasal administration is not applicable to all drugs. The current review presents the nasal anatomy and mucosal environment for the nasal delivery of vaccines and drugs, as well as presents various methods for enhancing nasal absorption, and different drug carriers and delivery devices to improve nasal drug delivery. It also presents future prospects on the nasal drug delivery of vaccines and drugs.

Pathogenic mechanisms and therapeutic promise of phytochemicals and nanocarriers based drug delivery against radiotherapy-induced neurotoxic manifestations

Radiotherapy is one of the extensively used therapeutic modalities in glioblastoma and other types of cancers. Radiotherapy is either used as a first-line approach or combined with pharmacotherapy or surgery to manage and treat cancer. Although the use of radiotherapy significantly increased the survival time of patients, but its use has been reported with marked neuroinflammation and cognitive dysfunction that eventually reduced the quality of life of patients. Based on the preclinical and clinical investigations, the profound role of increased oxidative stress, nuclear translocation of NF-kB, production of proinflammatory cytokines such as TNF-α, IL-6, IL-β, increased level of MMPs, increased apoptosis, reduced angiogenesis, neurogenesis, and histological aberrations in CA1, CA2, CA3 and DG region of the hippocampus have been reported. Various pharmacotherapeutic drugs are being used as an adjuvant to counteract this neurotoxic manifestation. Still, most of these drugs suffer from systemic adverse effect, causes interference to ongoing chemotherapy, and exhibit pharmacokinetic limitations in crossing the blood-brain barrier. Therefore, various phytoconstituents, their nano carrier-based drug delivery systems and miRNAs have been explored to overcome the aforementioned limitations. The present review is focused on the mechanism and evidence of radiotherapy-induced neuroinflammation and cognitive dysfunction, pathological and molecular changes in the brain homeostasis, available adjuvants, their limitations. Additionally, the potential role and mechanism of neuroprotection of various nanocarrier based natural products and miRNAs have been discussed.

Lipid-Based Nanocarriers for Neurological Disorders: A Review of the State-of-the-Art and Therapeutic Success to Date

Neurodegenerative disorders including Alzheimer's, Parkinson's, and dementia are chronic and advanced diseases that are associated with loss of neurons and other related pathologies. Furthermore, these disorders involve structural and functional defections of the blood-brain barrier (BBB). Consequently, advances in medicines and therapeutics have led to a better appreciation of various pathways associated with the development of neurodegenerative disorders, thus focusing on drug discovery and research for targeted drug therapy to the central nervous system (CNS). Although the BBB functions as a shield to prevent toxins in the blood from reaching the brain, drug delivery to the CNS is hindered by its presence. Owing to this, various formulation approaches, including the use of lipid-based nanocarriers, have been proposed to address shortcomings related to BBB permeation in CNS-targeted therapy, thus showing the potential of these carriers for translation into clinical use. Nevertheless, to date, none of these nanocarriers has been granted market authorization following the successful completion of all stages of clinical trials. While the aforementioned benefits of using lipid-based carriers underscores the need to fast-track their translational development into clinical practice, technological advances need to be initiated to achieve appropriate capacity for scale-up and the production of affordable dosage forms.

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.

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.

Anti-COVID-19 Nanomaterials: Directions to Improve Prevention, Diagnosis, and Treatment

Following the announcement of the outbreak of COVID-19 by the World Health Organization, unprecedented efforts were made by researchers around the world to combat the disease. So far, various methods have been developed to combat this "virus" nano enemy, in close collaboration with the clinical and scientific communities. Nanotechnology based on modifiable engineering materials and useful physicochemical properties has demonstrated several methods in the fight against SARS-CoV-2. Here, based on what has been clarified so far from the life cycle of SARS-CoV-2, through an interdisciplinary perspective based on computational science, engineering, pharmacology, medicine, biology, and virology, the role of nano-tools in the trio of prevention, diagnosis, and treatment is highlighted. The special properties of different nanomaterials have led to their widespread use in the development of personal protective equipment, anti-viral nano-coats, and disinfectants in the fight against SARS-CoV-2 out-body. The development of nano-based vaccines acts as a strong shield in-body. In addition, fast detection with high efficiency of SARS-CoV-2 by nanomaterial-based point-of-care devices is another nanotechnology capability. Finally, nanotechnology can play an effective role as an agents carrier, such as agents for blocking angiotensin-converting enzyme 2 (ACE2) receptors, gene editing agents, and therapeutic agents. As a general conclusion, it can be said that nanoparticles can be widely used in disinfection applications outside in vivo. However, in in vivo applications, although it has provided promising results, it still needs to be evaluated for possible unintended immunotoxicity. Reviews like these can be important documents for future unwanted pandemics.

Donepezil HCl Liposomes: Development, Characterization, Cytotoxicity, and Pharmacokinetic Study

The current research work aims to study the pharmacokinetic and nasal ciliotoxicity of donepezil liposome-based in situ gel to treat Alzheimer's disease. The physicochemical properties and first-pass metabolism of donepezil HCl result in low concentrations reaching the brain post oral administration. To overcome this problem, donepezil HCl-loaded liposomes were formulated using the ethanol injection method. The donepezil HCl-loaded liposomes were spherical with a size of 103 ± 6.2 nm, polydispersity index of 0.108 ± 0.008, and entrapment efficiency of 93 ± 5.33 %. The optimized in situ gel with donepezil HCl-loaded liposomes showed 80.11 ± 7.77 % drug permeation than donepezil HCl solution-based in situ gel (13.12 ± 4.84 %) across sheep nasal mucosa. The nasal ciliotoxicity study indicated the safety of developed formulation for administration via nasal route. The pharmacokinetics and biodistribution study of developed formulation showed higher drug concentration (1239.61 ± 123.60 pg/g) in the brain after nasal administration indicating its better potential via the nasal pathway. To treat Alzheimer's disease, the administration of liposome-based in situ gel through the nasal pathway can therefore be considered as an effective and promising mode of drug delivery.

Nose-to-brain drug delivery for the treatment of Alzheimer's Disease: Current advancements and challenges

INTRODUCTION

The irreversible destruction of neurons, progressive loss of memory and cognitive behavior, high cost of therapy, and impact on society desire a better, effective, and affordable treatment of AD. The nose-to-brain drug delivery approach holds a great potential to access the brain without any hindrance of BBB and result in higher bioavailability thus better therapeutic efficacy of anti-AD drugs.

AREAS COVERED

The present review article highlighted the current facts and worldwide statistics of AD and its detailed etiology. Followed by barriers to brain delivery, nose-to-brain delivery, their limitations, and amalgamation with various novel carrier systems. We have emphasized recent advancements in nose-to-brain delivery using mucoadhesive, stimuli-responsive carriers, polymeric nanoparticles, lipid nanoparticles, protein/peptide delivery for treatment of AD.

EXPERT OPINION

The available therapies are symptomatic, mitigate the symptoms of AD at the initial stages. In this lieu, nose-to-brain delivery has the ability to overcome these limitations and increase drug bioavailability in the brain. Various novel strategies including stimuli-responsive systems, nanoparticles, etc. enhance the nasal drug permeation, protects the drug, and enhance its therapeutic potency. Although, successful preclinical data does not assure the clinical success of the therapy and hence exhaustive clinical investigations are needed to make the therapy available for patients.

Using the Intranasal Route to Administer Drugs to Treat Neurological and Psychiatric Illnesses: Rationale, Successes, and Future Needs

While the intranasal administration of drugs to the brain has been gaining both research attention and regulatory success over the past several years, key fundamental and translational challenges remain to fully leveraging the promise of this drug delivery pathway for improving the treatment of various neurological and psychiatric illnesses. In response, this review highlights the current state of understanding of the nose-to-brain drug delivery pathway and how both biological and clinical barriers to drug transport using the pathway can been addressed, as illustrated by demonstrations of how currently approved intranasal sprays leverage these pathways to enable the design of successful therapies. Moving forward, aiming to better exploit the understanding of this fundamental pathway, we also outline the development of nanoparticle systems that show improvement in delivering approved drugs to the brain and how engineered nanoparticle formulations could aid in breakthroughs in terms of delivering emerging drugs and therapeutics while avoiding systemic adverse effects.

Designing nanoformulation for the nose-to-brain delivery in Parkinson's disease: Advancements and barrier

Parkinson's disease (PD), a neurodegenerative disorder characterized by the degeneration of dopaminergic neurons, which results in the loss of motor activity. In the management of PD, the primary aim is to increase the dopamine content in the brain either by delivering the precursors of dopamine or by inhibiting the molecules responsible for dopamine degradation. Due to the low bioavailability, a higher dosage of drugs needs to be administered repeatedly for achieving the desired therapeutic effect. This repeated high dose not only increases the severe side effects but also produces tolerance in the body. Often, direct administration of drugs fails to ameliorate the symptoms as the unmodified drugs cannot cross the blood-brain barrier (BBB). Nanotherapeutic is at the forefront of the alternative treatment against the central nervous system (CNS) disorders due to the ability to circumvents the BBB. Here, all the available treatments for PD have been discussed with their limitation. The current trends of nanotherapeutics for PD have been explored. Suitability and formulation prospects for nasal delivery have been analyzed in detail to explore new research scope. The most effective approach is the nose-to-brain delivery for targeting drugs directly to the brain. This delivery bypasses the BBB and concentrates more drugs at the target site. Thus, developments of nose-to-brain delivery of nanoformulations explicit the new scope to manage PD better. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

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.

Multi-disciplinary Approach for Drug and Gene Delivery Systems to the Brain

Drug delivery into the brain has for long been a huge challenge as the blood–brain barrier (BBB) offers great resistance to entry of foreign substances (with drugs inclusive) into the brain. This barrier in healthy individuals is protective to the brain, disallowing noxious substances present in the blood to get to the brain while allowing for the exchange of small molecules into the brain by diffusion. However, BBB is disrupted under certain disease conditions, such as cerebrovascular diseases including acute ischemic stroke and intracerebral hemorrhage, and neurodegenerative disorders including multiple sclerosis (MS), Alzheimer’s disease (AD), Parkinson’s disease (PD), and cancers. This review aims to provide a broad overview of present-day strategies for brain drug delivery, emphasizing novel delivery systems. Hopefully, this review would inspire scientists and researchers in the field of drug delivery across BBB to uncover new techniques and strategies to optimize drug delivery to the brain. Considering the anatomy, physiology, and pathophysiological functioning of the BBB in health and disease conditions, this review is focused on the controversies drawn from conclusions of recently published studies on issues such as the penetrability of nanoparticles into the brain, and whether active targeted drug delivery into the brain could be achieved with the use of nanoparticles. We also extended the review to cover novel non-nanoparticle strategies such as using viral and peptide vectors and other non-invasive techniques to enhance brain uptake of drugs.

Pulmonary delivery of osimertinib liposomes for non-small cell lung cancer treatment: formulation development and in vitro evaluation

Osimertinib (OB) is a third-generation irreversible tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR), overexpressed in non-small cell lung cancer. Systemic administration of drug often results in poor drug levels at the primary tumor in the lungs and is associated with systemic side effects. In this study, we developed inhalable OB liposomes that can locally accumulate at the tumor site thereby limiting systemic toxicity. OB was loaded into liposomes via active and passive loading methods. The OB active liposomes achieved a higher encapsulation (78%) compared to passive liposomes (25%). The liposomes (passive and active) exhibited excellent aerosolization performance with an aerodynamic diameter of 4 µm and fine particle fraction of 82%. In H1975 cells, OB active and passive liposomes reduced IC₅₀ by 2.2 and 1.2-fold, respectively, compared to free drug. As the OB active liposomes demonstrated higher cytotoxicity compared to OB passive liposomes, they were further investigated for in vitro anti-cancer activity. The OB active liposomes inhibited tumor cell migration and colonization as determined by the scratch assay and clonogenic assay, respectively. Furthermore, the 3D spheroid studies showed that the liposomes were successful in inhibiting tumor growth. These results highlight the potential of OB liposomes to suppress lung cancer. Owing to these attributes, the inhalable OB liposomes can potentially promote better therapeutic outcomes with limited systemic toxicity.

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.

The blood-tumour barrier in cancer biology and therapy

The protective blood-brain barrier has a major role in ensuring normal brain function by severely limiting and tightly controlling the ingress of substances into the brain from the circulation. In primary brain tumours, such as glioblastomas, as well as in brain metastases from cancers in other organs, including lung and breast cancers and melanoma, the blood-brain barrier is modified and is referred to as the blood-tumour barrier (BTB). Alterations in the BTB affect its permeability, and this structure participates in reciprocal regulatory pathways with tumour cells. Importantly, the BTB typically retains a heterogeneous capacity to restrict the penetration of many therapeutic agents into intracranial tumours, and overcoming this challenge is a key to improving the effectiveness of treatment and patient quality of life. Herein, current knowledge of BTB structure and function is reviewed from a cell and cancer biology standpoint, with a focus on findings derived from in vivo models and human tumour specimens. Additionally, how this knowledge can be translated into clinical advances for patients with cancer is discussed.

Liposomes: Structure, Biomedical Applications, and Stability Parameters With Emphasis on Cholesterol

Liposomes are essentially a subtype of nanoparticles comprising a hydrophobic tail and a hydrophilic head constituting a phospholipid membrane. The spherical or multilayered spherical structures of liposomes are highly rich in lipid contents with numerous criteria for their classification, including structural features, structural parameters, and size, synthesis methods, preparation, and drug loading. Despite various liposomal applications, such as drug, vaccine/gene delivery, biosensors fabrication, diagnosis, and food products applications, their use encounters many limitations due to physico-chemical instability as their stability is vigorously affected by the constituting ingredients wherein cholesterol performs a vital role in the stability of the liposomal membrane. It has well established that cholesterol exerts its impact by controlling fluidity, permeability, membrane strength, elasticity and stiffness, transition temperature (Tm), drug retention, phospholipid packing, and plasma stability. Although the undetermined optimum amount of cholesterol for preparing a stable and controlled release vehicle has been the downside, but researchers are still focused on cholesterol as a promising material for the stability of liposomes necessitating explanation for the stability promotion of liposomes. Herein, the prior art pertaining to the liposomal appliances, especially for drug delivery in cancer therapy, and their stability emphasizing the roles of cholesterol.

IFNγ-stimulated dendritic cell extracellular vesicles can be nasally administered to the brain and enter oligodendrocytes

Extracellular vesicles secreted from IFNγ-stimulated rat dendritic cells (referred to here as IFNγ-DC-EVs) contain miRNAs which promote myelination (including but not limited to miR-219), and preferentially enter oligodendrocytes in brain slice cultures. IFNγ-DC-EVs also increase myelination when nasally administered to naïve rats. While we can infer that these extracellular vesicles enter the CNS from functional studies, here we demonstrate biodistribution throughout the brain after nasal delivery by way of imaging studies. After nasal administration, Xenolight DiR-labelled IFNγ-DC-EVs were detected 30 minutes later throughout the brain and the cervical spinal cord. We next examined cellular uptake of IFNγ-DC-EVs by transfecting IFNγ-DC-EVs with mCherry mRNA prior to nasal administration. mCherry-positive cells were found along the rostrocaudal axis of the brain to the brainstem. These cells morphologically resembled oligodendrocytes, and indeed cell-specific co-staining for neurons, astrocytes, microglia and oligodendrocytes showed that mcherry positive cells were predominantly oligodendrocytes. This is in keeping with our prior in vitro results showing that IFNγ-DC-EVs are preferentially taken up by oligodendrocytes, and to a lesser extent, microglia. To confirm that IFNγ-DC-EVs delivered cargo to oligodendrocytes, we quantified protein levels of miR-219 mRNA targets expressed in oligodendrocyte lineage cells, and found significantly reduced expression. Finally, we compared intranasal versus intravenous delivery of Xenolight DiR-labelled IFNγ-DC-EVs. Though labelled IFNγ-DC-EVs entered the CNS via both routes, we found that nasal delivery more specifically targeted the CNS with less accumulation in the liver. Taken together, these data show that intranasal administration is an effective route for delivery of IFNγ-DC-EVs to the CNS, and provides additional support for their development as an EV-based neurotherapeutic that, for the first time, targets oligodendrocytes.

Progress in nasal drug delivery systems

Most of the available drugs are usually administered orally (e.g. in tablets or capsules) or by parenteral injection in the case of substances being destroyed in the gastric environment or not being absorbed. However, this bears disadvantages as many people have trouble swallowing tablets and parenteral injection requires trained personnel and/or a reasonably sterile environment to minimize the possibility of contamination. Thus, as an easy to use alternative nasal drug delivery was developed. Drug delivery systems are used to achieve a reproducible high drug concentration. These systems overcome various disadvantages leading to stabilization of the drug, advanced drug transport, improvement of the physicochemical properties of the drug like water solubility, and increase of drug uptake and bioavailability. In addition, properties such as bad taste or smell of the drug are masked. Nasal drug delivery systems are suitable for use both locally and systemically. In the last five years, the development and progression of nasal drug delivery systems has gained importance due to their numerous advantages. This work gives an overview of the basics, such as structure and function of the nose, as well as a short introduction to local and systemic application of drugs. Furthermore, selected drug delivery systems are explained with examples of active ingredients, as well as additional possibilities to increase nasal drug uptake and factors influencing the absorption.

Nanotechnology against COVID-19: Immunization, diagnostic and therapeutic studies

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in early 2020 soon led to the global pandemic of Coronavirus Disease 2019 (COVID-19). Since then, the clinical and scientific communities have been closely collaborating to develop effective strategies for controlling the ongoing pandemic. The game-changing fields of recent years, nanotechnology and nanomedicine have the potential to not only design new approaches, but also to improve existing methods for the fight against COVID-19. Nanomaterials can be used in the development of highly efficient, reusable personal protective equipment, and antiviral nano-coatings in public settings could prevent the spread of SARS-CoV-2. Smart nanocarriers have accelerated the design of several therapeutic, prophylactic, or immune-mediated approaches against COVID-19. Some nanovaccines have even entered Phase IΙ/IIΙ clinical trials. Several rapid and cost-effective COVID-19 diagnostic techniques have also been devised based on nanobiosensors, lab-on-a-chip systems, or nanopore technology. Here, we provide an overview of the emerging role of nanotechnology in the prevention, diagnosis, and treatment of COVID-19.

Pharmacokinetic and pharmacodynamic evaluation of nasal liposome and nanoparticle based rivastigmine formulations in acute and chronic models of Alzheimer's disease

With the increasing aging population and progressive nature of the disease, Alzheimer's disease (AD) poses to be an oncoming epidemic with limited therapeutic strategies. It is characterized by memory loss, behavioral instability, impaired cognitive function, predominantly, cognitive inability manifested due to the accumulation of β-amyloid, with malfunctioned cholinergic system. Rivastigmine, a reversible dual cholinesterase inhibitor, is a more tolerable and widely used choice of drug for AD. However, rivastigmine being hydrophilic and undergoing the first-pass metabolism exhibits low CNS bioavailability. Nanoformulations including liposomes and PLGA nanoparticles can encapsulate hydrophilic drugs and deliver them efficiently to the brain. Besides, the nasal route is receiving considerable attention recently, due to its direct access to the brain. Therefore, the present study attempts to evaluate the pharmacokinetic and pharmacodynamic properties of nasal liposomal and PLGA nanoparticle formulations of rivastigmine in acute scopolamine-induced amnesia and chronic colchicine induced cognitive dysfunction animal models, and validate the best formulation by employing pharmacokinetic and pharmacodynamic (PK-PD) modeling. Nasal liposomal rivastigmine formulation showed the best pharmacokinetic features with rapid onset of action (Tmax = 5 min), higher Cmax (1489.5 ± 620.71), enhanced systemic bioavailability (F = 118.65 ± 23.54; AUC = 35,921.75 ± 9559.46), increased half-life (30.92 ± 8.38 min), and reduced clearance rate (Kel (1/min) = 0.0224 ± 0.006) compared to oral rivastigmine (Tmax = 15 min; Cmax = 56.29 ± 27.05; F = 4.39 ± 1.82; AUC = 1663.79 ± 813.54; t1/2 = 13.48 ± 5.79; Kel (1/min) = 0.0514 ± 0.023). Further, the liposomal formulation significantly rescued the memory deficit induced by scopolamine as well as colchicine superior to other formulations as assessed in Morris water maze and passive avoidance tasks. PK-PD modeling demonstrated a strong correlation between the pharmacokinetic parameters and acetylcholinesterase inhibition of liposomal formulation.

Intranasal Administration for Pain: Oxytocin and Other Polypeptides

Pain, particularly chronic pain, remains one of the most debilitating and difficult-to-treat conditions in medicine. Chronic pain is difficult to treat, in part because it is associated with plastic changes in the peripheral and central nervous systems. Polypeptides are linear organic polymers that are highly selective molecules for neurotransmitter and other nervous system receptors sites, including those associated with pain and analgesia, and so have tremendous potential in pain therapeutics. However, delivery of polypeptides to the nervous system is largely limited due to rapid degradation within the peripheral circulation as well as the blood–brain barrier. One strategy that has been shown to be successful in nervous system deposition of polypeptides is intranasal (IN) delivery. In this narrative review, we discuss the delivery of polypeptides to the peripheral and central nervous systems following IN administration. We briefly discuss the mechanism of delivery via the nasal–cerebral pathway. We review recent studies that demonstrate that polypeptides such as oxytocin, delivered IN, not only reach key pain-modulating regions in the nervous system but, in doing so, evoke significant analgesic effects. IN administration of polypeptides has tremendous potential to provide a non-invasive, rapid and effective method of delivery to the nervous system for chronic pain treatment and management.

Membrane Derived Vesicles as Biomimetic Carriers for Targeted Drug Delivery System

Extracellular vesicles (EVs) are membrane vesicles (MVs) playing important roles in various cellular and molecular functions in cell-to-cell signaling and transmitting molecular signals to adjacent as well as distant cells. The preserved cell membrane characteristics in MVs derived from live cells, give them great potential in biological applications. EVs are nanoscale particulates secreted from living cells and play crucial roles in several important cellular functions both in physiological and pathological states. EVs are the main elements in intercellular communication in which they serve as carriers for various endogenous cargo molecules, such as RNAs, proteins, carbohydrates, and lipids. High tissue tropism capacity that can be conveniently mediated by surface molecules, such as integrins and glycans, is a unique feature of EVs that makes them interesting candidates for targeted drug delivery systems. The cell-derived giant MVs have been exploited as vehicles for delivery of various anticancer agents and imaging probes and for implementing combinational phototherapy for targeted cancer treatment. Giant MVs can efficiently encapsulate therapeutic drugs and deliver them to target cells through the membrane fusion process to synergize photodynamic/photothermal treatment under light exposure. EVs can load diagnostic or therapeutic agents using different encapsulation or conjugation methods. Moreover, to prolong the blood circulation and enhance the targeting of the loaded agents, a variety of modification strategies can be exploited. This paper reviews the EVs-based drug delivery strategies in cancer therapy. Biological, pharmacokinetics and physicochemical characteristics, isolation techniques, engineering, and drug loading strategies of EVs are discussed. The recent preclinical and clinical progresses in applications of EVs and oncolytic virus therapy based on EVs, the clinical challenges and perspectives are discussed.

Improving Drug Delivery for Alzheimer's Disease Through Nose-to-Brain Delivery Using Nanoemulsions, Nanostructured Lipid Carriers (NLC) and in situ Hydrogels

Current treatments for Alzheimer's disease (AD) attenuate the progression of symptoms and aim to improve the patient's quality of life. Licensed medicines are mostly for oral administration and are limited by the difficulty in crossing the blood-brain barrier (BBB). Here in, the nasal route has been explored as an alternative pathway that allows drugs to be directly delivered to the brain via the nasal cavity. However, clearance mechanisms in the nasal cavity impair the delivery of drugs to the brain and limit their bioavailability. To optimize nose-to-brain delivery, formulations of lipid-based nanosystems, namely nanoemulsions and nanostructured lipid carriers (NLC), formulated in situ gelling hydrogels have been proposed as approaches for nose-to-brain delivery. These formulations possess characteristics that facilitate drug transport directly to the brain, minimizing side effects and maximizing therapeutic benefits. It has been recommended that the manufacture of these drug delivery systems follows the quality by design (QbD) approach based on nasal administration requirements. This review provides an insight into the current knowledge of the AD, highlighting the need for an effective drug delivery to the brain. Considering the mounting interest in the use of nanoemulsions and NLC for nose-to-brain delivery, a description of drug transport pathways in the nasal cavity and the application of these nanosystems and their in situ hydrogels through the intranasal route are presented. Relevant preclinical studies are summarised, and the future prospects for the use of lipid-based nanosystems in the treatment of AD are emphasized.

Subcutaneously Injectable Hyaluronic Acid Hydrogel for Sustained Release of Donepezil with Reduced Initial Burst Release: Effect of Hybridization of Microstructured Lipid Carriers and Albumin

The daily oral administration of acetylcholinesterase (AChE) inhibitors for Alzheimer’s disease features low patient compliance and can lead to low efficacy or high toxicity owing to irregular intake. Herein, we developed a subcutaneously injectable hyaluronic acid hydrogel (MLC/HSA hydrogel) hybridized with microstructured lipid carriers (MLCs) and human serum albumin (HSA) for the sustained release of donepezil (DNP) with reduced initial burst release. The lipid carrier was designed to have a microsized mean diameter (32.6 ± 12.8 µm) to be well-localized in the hydrogel. The hybridization of MLCs and HSA enhanced the structural integrity of the HA hydrogel, as demonstrated by the measurements of storage modulus (G′), loss modulus (G″), and viscosity. In the pharmacokinetic study, subcutaneous administration of MLC/HSA hydrogel in rats prolonged the release of DNP for up to seven days and reduced the initial plasma concentration, where the C_max value was 0.3-fold lower than that of the control hydrogel without a significant change in the AUC_last value. Histological analyses of the hydrogels supported their biocompatibility for subcutaneous injection. These results suggest that a new hybrid MLC/HSA hydrogel could be promising as a subcutaneously injectable controlled drug delivery system for the treatment of Alzheimer’s disease.

Gene therapy avenues and COVID-19 vaccines

2020 has witnessed unprecedented situations due to coronavirus pandemic that affected all aspects of life. The whole globe lived months of uncertainty before two companies have announced the incredible results of phase III clinical trials for two different mRNA-based vaccines.

Intranasal In Situ Gel of Apixaban-Loaded Nanoethosomes: Preparation, Optimization, and In Vivo Evaluation

The present study was conducted to formulate ethosomal thermoreversible in situ gel of apixaban, an anticoagulant drug, for nasal delivery. Ethosomes were formed, of lecithin, cholesterol, and ethanol, by using thin-film hydration method. The prepared ethosomes were characterized by Zetasizer, transmission electron microscope, entrapment efficiency, and in vitro study. The selected ethosomal formula (API-ETHO2) was incorporated in gel using P407 and P188 as thermoreversible agents and carbopol 934 as mucoadhesive agent. Box-Behnken design was used to study the effect of independent variables (concentration of P407, P188, and carbopol 934) on gelation temperature, mucoadhesive strength, and in vitro cumulative percent drug released at 12h (response variables). The optimized formulation was subjected to compatibility study, ex vivo permeation, histopathological examination for the nasal mucosa, and in vivo study. API-ETHO2 was spherical with an average size of 145.1±12.3 nm, zeta potential of -20±4 mV, entrapment efficiency of 67.11%±3.26, and in vitro % release of 79.54%±4.1. All gel formulations exhibited an acceptable pH and drug content. The optimum gel offered 32.3°C, 1226.3 dyne/cm², and 53.50% for gelation temperature, mucoadhesive strength, and in vitro percent released, respectively. Apixaban ethosomal in situ gel evolved higher ex vivo permeation (1.499±0.11 μg/cm²h) through the nasal mucosa than pure apixaban gel. Histopathological study assured that there is no necrosis or tearing of the nasal mucosa happened by ethosomal gel. The pharmacokinetic parameters in rabbit plasma showed that intranasal administration of optimized API-ethosomal in situ gel achieved higher C_max and AUC_0-∞ than unprocessed API nasal gel, nasal suspension, and oral suspension. The ethosomal thermoreversible nasal gel established its potential to improve nasal permeation and prolong anticoagulant effect of apixaban.

Development of In Situ Gelling Meloxicam-Human Serum Albumin Nanoparticle Formulation for Nose-to-Brain Application

The aim of this study was to develop an intranasal in situ thermo-gelling meloxicam-human serum albumin (MEL-HSA) nanoparticulate formulation applying poloxamer 407 (P407), which can be administered in liquid state into the nostril, and to increase the resistance of the formulation against mucociliary clearance by sol-gel transition on the nasal mucosa, as well as to improve drug absorption. Nanoparticle characterization showed that formulations containing 12-15% w/w P407 met the requirements of intranasal administration. The Z-average (in the range of 180-304 nm), the narrow polydispersity index (PdI, from 0.193 to 0.328), the zeta potential (between -9.4 and -7.0 mV) and the hypotonic osmolality (200-278 mOsmol/L) of MEL-HSA nanoparticles predict enhanced drug absorption through the nasal mucosa. Based on the rheological, muco-adhesion, drug release and permeability studies, the 14% w/w P407 containing formulation (MEL-HSA-P14%) was considered as the optimized formulation, which allows enhanced permeability of MEL through blood-brain barrier-specific lipid fraction. Cell line studies showed no cell damage after 1-h treatment with MEL-HSA-P14% on RPMI 2650 human endothelial cells' moreover, enhanced permeation (four-fold) of MEL from MEL-HSA-P14% was observed in comparison to pure MEL. Overall, MEL-HSA-P14% can be promising for overcoming the challenges of nasal drug delivery.

Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery. This review aims at overviewing recent developments of inorganic nanoparticles (like porous or mesoporous silica particles) and different nano-clay materials (like montmorillonite, laponites or halloysite nanotubes) employed for overcoming the blood brain barrier (BBB) in the treatment and therapy of major brain diseases such as Alzheimer's, Parkinson's, glioma or amyotrophic lateral sclerosis. Recent strategies of crossing the BBB through invasive and not invasive administration routes by using different types of nanoparticles compared to nano-clays and inorganic particles are overviewed.

Design, development and in-vitro/in-vivo evaluation of intranasally delivered Rivastigmine and N-Acetyl Cysteine loaded bifunctional niosomes for applications in combinative treatment of Alzheimer's disease

The present investigation explores the potential of novel dual drug-loaded niosomes for nasal delivery of Rivastigmine (RIV) and N-Acetyl Cysteine (NAC) to the brain. The dual niosomes showed a particle size of 162.4 nm and % entrapment efficiencies of 97.7% for RIV and 85.9% for NAC. The niosomes were statistically validated using Box-Behnken experimental design (BBD) with good significance. Ultrastructural and chemical characterization of the niosomes using various analytical techniques like Fourier Transform Infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Transmission electron microscopy (TEM) showcased drug-excipient compatibility and robust stability of 6 months in a liquid state at 4-8 °C. The dual drug-loaded niosomes showed a sustained drug release pattern up to 2 days. Acetylcholinesterase (AChE) and DPPH (1, 1-diphenyl-2- picrylhydrazyl) enzyme inhibition assays showed a better combinative effect than the free drug solutions. A 2-day nasal permeation proved the effectiveness and biocompatibility of the niosomes. In-vivo pharmacokinetic and organ biodistribution studies revealed a better drug profile and greater distribution of the niosomes in the brain compared to other organs, thereby indicating a direct nose-to-brain delivery of the niosomes.

Quality-by-Design-Based Development of n-Propyl-Gallate-Loaded Hyaluronic-Acid-Coated Liposomes for Intranasal Administration

The present study aimed to develop n-propyl gallate (PG)-encapsulated liposomes through a novel direct pouring method using the quality-by-design (QbD) approach. A further aim was to coat liposomes with hyaluronic acid (HA) to improve the stability of the formulation in nasal mucosa. The QbD method was used for the determination of critical quality attributes in the formulation of PG-loaded liposomes coated with HA. The optimized formulation was determined by applying the Box–Behnken design to investigate the effect of composition and process variables on particle size, polydispersity index (PDI), and zeta potential. Physiochemical characterization, in vitro release, and permeability tests, as well as accelerated stability studies, were performed with the optimized liposomal formulation. The optimized formulation resulted in 90 ± 3.6% encapsulation efficiency, 167.9 ± 3.5 nm average hydrodynamic diameter, 0.129 ± 0.002 PDI, and −33.9 ± 4.5 zeta potential. Coated liposomes showed significantly improved properties in 24 h in an in vitro release test (>60%), in vitro permeability measurement (420 μg/cm²) within 60 min, and also in accelerated stability studies compared to uncoated liposomes. A hydrogen-peroxide-scavenging assay showed improved stability of PG-containing liposomes. It can be concluded that the optimization of PG-encapsulated liposomes coated with HA has great potential for targeting several brain diseases.

RVG29-modified microRNA-loaded nanoparticles improve ischemic brain injury by nasal delivery

Effective nose-to-brain delivery needs to be developed to treat neurodegenerative diseases. Regulating miR-124 can effectively improve the symptoms of ischemic brain injury and provide a certain protective effect from brain damage after cerebral ischemia. We used rat models of middle cerebral artery occlusion (t-MCAO) with ischemic brain injury, and we delivered RVG29-NPs-miR124 intranasally to treat neurological damage after cerebral ischemia. Rhoa and neurological scores in rats treated by intranasal administration of RVG29-PEG-PLGA/miRNA-124 were significantly lower than those in PEG-PLGA/miRNA-124 nasal administration and RVG29-PLGA/miRNA-124 nasal administration group treated rats. These results indicate that the nose-to-brain delivery of PLGA/miRNA-124 conjugated with PEG and RVG29 alleviated the symptoms of cerebral ischemia-reperfusion injury. Thus, nasal delivery of RVG29-PEG-PLGA/miRNA-124 could be a new method for treating neurodegenerative diseases.

The New Frontiers in Neurodegenerative Diseases Treatment: Liposomal-Based Strategies

In the last decade, the onset of neurodegenerative (ND) diseases is strongly widespread due to the age increase of the world population. Despite the intensive investigations boosted by the scientific community, an efficacious therapy has not been outlined yet. The drugs commonly used are only able to relieve symptom severity; following their oral or intravenous administration routes, their effectiveness is strictly limited due to their low ability to reach the Central Nervous System (CNS) overcoming the Blood Brain Barrier (BBB). Starting from these assumptions, the engineered-nanocarriers, such as lipid-nanocarriers, are suitable agents to enhance the delivery of drugs into the CNS due to their high solubility, bioavailability, and stability. Liposomal delivery systems are considered to be the ideal carriers, not only for conventional drugs but also for neuroprotective small molecules and green-extracted compounds. In the current work, the LP-based drug delivery improvements in in vivo applications against ND disorders were carefully assessed.

Nanotechnology Assisted Targeted Drug Delivery for Bone Disorders: Potentials and Clinical Perspectives

Nanotechnology and its allied modalities have brought revolution in tissue engineering and bone healing. The research on translating the findings of the basic and preclinical research into clinical practice is ongoing. Advances in the synthesis and design of nanomaterials along with advances in genomics and proteomics, and tissue engineering have opened a bright future for bone healing and orthopedic technology. Studies have shown promising outcomes in the design and fabrication of porous implant substrates that can be exploited as bone defect augmentation and drug-carrier devices. However, there are dozens of applications in orthopedic traumatology and bone healing for nanometer-sized entities, structures, surfaces, and devices with characteristic lengths ranging from tens 10s of nanometers to a few micrometers. Nanotechnology has made promising advances in the synthesis of scaffolds, delivery mechanisms, controlled modification of surface topography and composition, and biomicroelectromechanical systems. This study reviews the basic and translational sciences and clinical implications of the nanotechnology in tissue engineering and bone diseases. Recent advances in NPs assisted osteogenic agents, nanocomposites, and scaffolds for bone disorders are discussed.

The Role of Natural Compounds and their Nanocarriers in the Treatment of CNS Inflammation

Neuroinflammation, which is involved in various inflammatory cascades in nervous tissues, can result in persistent and chronic apoptotic neuronal cell death and programmed cell death, triggering various degenerative disorders of the central nervous system (CNS). The neuroprotective effects of natural compounds against neuroinflammation are mainly mediated by their antioxidant, anti-inflammatory, and antiapoptotic properties that specifically promote or inhibit various molecular signal transduction pathways. However, natural compounds have several limitations, such as their pharmacokinetic properties and stability, which hinder their clinical development and use as medicines. This review discusses the molecular mechanisms of neuroinflammation and degenerative diseases of CNS. In addition, it emphasizes potential natural compounds and their promising nanocarriers for overcoming their limitations in the treatment of neuroinflammation. Moreover, recent promising CNS inflammation-targeted nanocarrier systems implementing lesion site-specific active targeting strategies for CNS inflammation are also discussed.

Management of epileptic disorders using nanotechnology-based strategies for nose-to-brain drug delivery

INTRODUCTION

Epilepsy, a major neurological disorder affects about 1% of the Indian population. The discovery of noninvasive strategies for epilepsy presents a challenge for the scientists. Different types of nose-to-brain dosage-forms have been studied for epilepsy management. It aims to give new perspectives for developing new and existing anti-epileptic drugs. Combining nanotechnology with nose-to-brain approach can help in promoting the treatment efficacy by site-specific delivery. Also, it will minimize the side-effects and patient noncompliance observed in conventional administration routes. Peptide delivery can be an interesting approach for the management of epilepsy. Drug-loaded intranasal nanoformulations exhibit diverse prospective potentials in the management of epilepsy. Considering that, nanotherapy using nose-to-brain delivery as a prospective technique for the efficient management of epilepsy is reviewed.

AREAS COVERED

The authors have compiled all recently available data pertaining to the nose-to-brain delivery of therapeutics using nanotechnological strategies. The fundamental mechanism of nose-to-brain delivery, claims for intranasal delivery and medical devices for epilepsy are discussed.

EXPERT OPINION

Drug-loaded intranasal nanoformulations exhibit different prospective potentials in the management of epilepsy. Considering the foregoing research done in the field of nanotechnology, globally, authors propose nose-to-brain delivery of nanoformulations as a potential technique for the efficient management of epilepsy.

Mastering the Tools: Natural versus Artificial Vesicles in Nanomedicine

Naturally occurring extracellular vesicles and artificially made vesicles represent important tools in nanomedicine for the efficient delivery of biomolecules and drugs. Since its first appearance in the literature 50 years ago, the research on vesicles is progressing at a fast pace, with the main goal of developing carriers able to protect cargoes from degradation, as well as to deliver them in a time- and space-controlled fashion. While natural occurring vesicles have the advantage of being fully compatible with their host, artificial vesicles can be easily synthetized and functionalized according to the target to reach. Research is striving to merge the advantages of natural and artificial vesicles, in order to provide a new generation of highly performing vesicles, which would improve the therapeutic index of transported molecules. This progress report summarizes current manufacturing techniques used to produce both natural and artificial vesicles, exploring the promises and pitfalls of the different production processes. Finally, pros and cons of natural versus artificial vesicles are discussed and compared, with special regard toward the current applications of both kinds of vesicles in the healthcare field.

Formulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, box benhken design and artificial neural networks

The aim of this research was to develop lamotrigine containing thermosetting hydrogel for intranasal administration to manage and treat generalized epilepsy. Thermosetting hydrogels were prepared using different ratios of poloxamer 407 (L127), poloxamer 188 (L68) and Carbopol^® 974 P NF (C974) using the cold production process. The in situ thermosetting hydrogel was optimized using Box Behken design. Co-solvency approach was used to increase the solubility of lamotrigine by dissolving it in propylene glycol and polyethylene glycol 400 (0.2: 0.8) and the resultant solution was incorporated in the hydrogel to manufacture an LTG hydrogel. The presence of a higher amount of L127 resulted in higher viscosity at 22 °C and 34 °C and decreased the overall release of LTG. An increase in the amount of C974 resulted in a decrease in the pH of the hydrogel. The results show that formulations F10, F12, F13, F14, F15, F16 and F17 exhibited acceptable thermosetting behavior, pH and released adequate Lamotrigine above the minimum effective concentration to treat generalized epilepsy. The optimized formulation exhibited acceptable thermosetting behavior, pH and lamotrigine release but formed a stiff gel at 22 °C. The average LTG content of the optimized hydrogel was 5.00 ± 0.0225 mg/ml with % recovery of 99.17%. The amount of LTG released at 12 h from the optimized hydrogel was 3.21 ± 0.0155 mg and will be therapeutically effective in the brain after absorption via the olfactory region in the nasal cavity.

Intranasal Antiviral Drug Delivery and Coronavirus Disease 2019 (COVID-19): A State of the Art Review

OBJECTIVE

To provide a state of the art review of intranasal antiviral drug delivery and to discuss current applications, adverse reactions, and future considerations in the management of coronavirus disease 2019 (COVID-19).

DATA SOURCES

PubMed, Embase, and Clinicaltrials.gov search engines.

REVIEW METHODS

A structured search of the current literature was performed of dates up to and including April 2020. Search terms were queried as related to topics of antiviral agents and intranasal applications. A series of video conferences was convened among experts in otolaryngology, infectious diseases, public health, pharmacology, and virology to review the literature and discuss relevant findings.

CONCLUSIONS

Intranasal drug delivery for antiviral agents has been studied for many years. Several agents have broad-spectrum antiviral activity, but they still require human safety and efficacy trials prior to implementation. Intranasal drug delivery has potential relevance for future clinical trials in the settings of disease spread prevention and treatment of SARS-CoV-2 and other viral diseases.

IMPLICATIONS FOR PRACTICE

Intranasal drug delivery represents an important area of research for COVID-19 and other viral diseases. The consideration of any potential adverse reactions is paramount.

Bi-functional sterically hindered phenol lipid-based delivery systems as potential multi-target agents against Alzheimer's disease via an intranasal route

New lipid-based nanomaterials and multi-target directed ligands (MTDLs) based on sterically hindered phenol, containing a quaternary ammonium moiety (SHP-s-R, with s = 2,3) of varying hydrophobicity (R = CH2Ph and CnH2n+1, with n = 8, 10, 12, 16), have been prepared as potential drugs against Alzheimer's disease (AD). SHP-s-R are inhibitors of human cholinesterases with antioxidant properties. The inhibitory potency of SHP-s-R and selectivity ratio of cholinesterase inhibition were found to significantly depend on the length of the methylene spacer (s) and alkyl chain length. The compound SHP-2-16 showed the best IC50 for human AChE and the highest selectivity, being 30-fold more potent than for human BChE. Molecular modeling of SHP-2-16 binding to human AChE suggests that this compound is a dual binding site inhibitor that interacts with both the peripheral anionic site and catalytic active site. The relationship between self-assembly parameters (CMC, solubilization capacity, aggregation number), antioxidant activity and a toxicological parameter (hemolytic action on human red blood cells) was investigated. Two sterically hindered phenols (SHP-2-Bn and SHP-2-R) were loaded into L-α-phosphatidylcholine (PC) nanoparticles by varying the SHP alkyl chain length. For the brain AChE inhibition assay, PC/SHP-2-Bn/SHP-2-16 nanoparticles were administered to rats intranasally at a dose of 8 mg kg-1. The Morris water maze experiment showed that scopolamine-induced AD-like dementia in rats treated with PC/SHP-2-Bn/SHP-2-16 nanoparticles was significantly reduced. This is the first example of cationic SHP-phospholipid nanoparticles for inhibition of brain cholinesterases realized by the use of intranasal administration. This route has promising potential for the treatment of AD.

Nose-to-brain delivery of antipsychotics using nanotechnology: a review

INTRODUCTION

Orally-administered antipsychotics are effective in the management of psychosis-related disorders although generation-specific adverse drug reactions (ADRs) significantly hinder clinical outcomes, driven by issues such as patient non-compliance. Direct nose-to-brain (N2B) delivery of antipsychotics via the olfactory epithelium could avert peripheral ADRs by maximizing cerebral drug concentrations, and reducing drug levels in the periphery. However, there exist physicochemical challenges related to psychotropic drugs, alongside biochemical barriers associated with targeting the olfactory region. Nanotechnological approaches present a viable strategy for the development of intranasal antipsychotic formulations where drug stability, mucosal absorption and cerebrospinal fluid (CSF)-bioavailability can be optimized.

AREAS COVERED

This review explores the unique anatomical features of the nasal cavity as a pathway for antipsychotic drug delivery to the brain. Nanocarrier-based approaches to encapsulate antipsychotics, and enhance stability, absorption and bioavailability are explored. The aim of this review is to determine current knowledge gaps for direct N2B psychotropic drug delivery, and identify clinically acceptable strategies to overcome them.

EXPERT OPINION

The olfactory epithelium may be the most effective and direct administration route for antipsychotic delivery to the central nervous system (CNS). This research is novel and has the potential to revolutionize the mode of delivery of neurological medicines to the CNS in the future.