Polysorbate 80 coated crosslinked chitosan nanoparticles of ropinirole hydrochloride for brain targeting

Drug Delivery Across the Blood-Brain Barrier: A New Strategy for the Treatment of Neurological Diseases

The blood-brain barrier (BBB) serves as a highly selective barrier between the blood and the central nervous system (CNS), and its main function is to protect the brain from foreign substances. This physiological property plays a crucial role in maintaining CNS homeostasis, but at the same time greatly limits the delivery of drug molecules to the CNS, thus posing a major challenge for the treatment of neurological diseases. Given that the high incidence and low cure rate of neurological diseases have become a global public health problem, the development of effective BBB penetration technologies is important for enhancing the efficiency of CNS drug delivery, reducing systemic toxicity, and improving the therapeutic outcomes of neurological diseases. This review describes the physiological and pathological properties of the BBB, as well as the current challenges of trans-BBB drug delivery, detailing the structural basis of the BBB and its role in CNS protection. Secondly, this paper reviews the drug delivery strategies for the BBB in recent years, including physical, biological and chemical approaches, as well as nanoparticle-based delivery technologies, and provides a comprehensive assessment of the effectiveness, advantages and limitations of these delivery strategies. It is hoped that the review in this paper will provide valuable references and inspiration for future researchers in therapeutic studies of neurological diseases.

Exploring chitosan nanoparticles for enhanced therapy in neurological disorders: a comprehensive review

Chitosan nanoparticles have emerged as a promising therapeutic platform for treating neurological disorders due to their biocompatibility, biodegradability, and ease of functionalization. One of the significant challenges in treating neurological conditions is overcoming the blood-brain barrier (BBB), which restricts the effective delivery of therapeutic agents to the brain. Addressing this barrier is crucial for the successful treatment of various neurological diseases, including Alzheimer's disease, Parkinson's disease, epilepsy, migraine, psychotic disorders, and brain tumors. Chitosan nanoparticles offer several advantages: they enhance drug absorption, protect drugs from degradation, and enable targeted delivery. These properties open new possibilities for non-invasive therapies for neurological conditions. Numerous studies have highlighted the neuroprotective potential of chitosan nanoparticles, demonstrating improved outcomes in animal models of neurodegeneration and neuroinflammation. Additionally, surface modifications of these nanoparticles allow for the attachment of specific ligands or molecules, enhancing the precision of drug delivery to neuronal cells. Despite these advancements, several challenges persist in the clinical translation of chitosan nanoparticles. Issues such as large-scale production, regulatory hurdles, and the need for further research into long-term safety must be addressed. This review explores recent advancements in the use of chitosan nanoparticles for managing neurological disorders and outlines potential future directions in this rapidly evolving field of research.

Polysorbate 80 coated chitosan nanoparticles for delivery of α-melanocyte stimulating hormone analog (NDP-MSH) to the brain reverse cognitive impairment related to neuroinflammation produced by a high-fat diet (HFD)

This study aimed to develop polysorbate 80-coated chitosan nanoparticles (PS80/CS NPs) as a delivery system for improved brain targeting of α-Melanocyte Stimulating Hormone analog (NDP-MSH). Chitosan nanoparticles loaded with NDP-MSH were surface-modified with polysorbate 80 ([NDP-MSH]-PS80/CS NP), which formed a flattened layer on their surface. Nanoparticle preparation involved ionic gelation, followed by characterization using scanning electron microscopy (SEM) for morphology, dynamic light scattering (DLS) for colloidal properties, and ATR-FTIR spectroscopy for structure. Intraperitoneal injection of FITC-PS80/CS NPs and [NDP-MSH]-PS80/CS NP in rats demonstrated their ability to cross the blood-brain barrier, reach the brain, and accumulate in CA1 neurons of the dorsal hippocampus within 2 h. Two experimental models of neuroinflammation were employed with Male Wistar rats: a short-term model involving high-fat diet (HFD) consumption for 5 days followed by an immune stimulus with LPS, and a long-term model involving HFD consumption for 8 weeks. In both models, [NDP-MSH]-PS80/CS NPs could reverse the decreased expression of contextual fear memory induced by the diets. These findings suggest that [NDP-MSH]-PS80/CS NPs offer a promising strategy to overcome the limitations of NDP-MSH regarding pharmacokinetics and enzymatic stability. By facilitating NDP-MSH delivery to the hippocampus, these nanoparticles can potentially mitigate the cognitive impairments associated with HFD consumption and neuroinflammation.

Biopolymers as promising vehicles for drug delivery to the brain

The brain is a privileged organ, tightly guarded by a network of endothelial cells, pericytes, and glial cells called the blood brain barrier. This barrier facilitates tight regulation of the transport of molecules, ions, and cells from the blood to the brain. While this feature ensures protection to the brain, it also presents a challenge for drug delivery for brain diseases. It is, therefore, crucial to identify molecules and/or vehicles that carry drugs, cross the blood brain barrier, and reach targets within the central nervous system. Biopolymers are large polymeric molecules obtained from biological sources. In comparison with synthetic polymers, biopolymers are structurally more complex and their 3D architecture makes them biologically active. Researchers are therefore investigating biopolymers as safe and efficient carriers of brain-targeted therapeutic agents. In this article, we bring together various approaches toward achieving this objective with a note on the prospects for biopolymer-based neurotherapeutic/neurorestorative/neuroprotective interventions. Finally, as a representative paradigm, we discuss the potential use of nanocarrier biopolymers in targeting protein aggregation diseases.

Application of Nanocomposites and Nanoparticles in Treating Neurodegenerative Disorders

Neurodegenerative diseases represent a formidable global health challenge, affecting millions and imposing substantial burdens on healthcare systems worldwide. Conditions, like Alzheimer's, Parkinson's, and Huntington's diseases, among others, share common characteristics, such as neuronal loss, misfolded protein aggregation, and nervous system dysfunction. One of the major obstacles in treating these diseases is the presence of the blood-brain barrier, limiting the delivery of therapeutic agents to the central nervous system. Nanotechnology offers promising solutions to overcome these challenges. In Alzheimer's disease, NPs loaded with various compounds have shown remarkable promise in preventing amyloid-beta (Aβ) aggregation and reducing neurotoxicity. Parkinson's disease benefits from improved dopamine delivery and neuroprotection. Huntington's disease poses its own set of challenges, but nanotechnology continues to offer innovative solutions. The promising developments in nanoparticle-based interventions for neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS), have offered new avenues for effective treatment. Nanotechnology represents a promising frontier in biomedical research, offering tailored solutions to the complex challenges posed by neurodegenerative diseases. While much progress has been made, ongoing research is essential to optimize nanomaterial designs, improve targeting, and ensure biocompatibility and safety. Nanomaterials possess unique properties that make them excellent candidates for targeted drug delivery and neuroprotection. They can effectively bypass the blood-brain barrier, opening doors to precise drug delivery strategies. This review explores the extensive research on nanoparticles (NPs) and nanocomposites in diagnosing and treating neurodegenerative disorders. These nanomaterials exhibit exceptional abilities to target neurodegenerative processes and halt disease progression.

The Advancement and Obstacles in Improving the Stability of Nanocarriers for Precision Drug Delivery in the Field of Nanomedicine

Nanocarriers have emerged as a promising class of nanoscale materials in the fields of drug delivery and biomedical applications. Their unique properties, such as high surface area- tovolume ratios and enhanced permeability and retention effects, enable targeted delivery of therapeutic agents to specific tissues or cells. However, the inherent instability of nanocarriers poses significant challenges to their successful application. This review highlights the importance of nanocarrier stability in biomedical applications and its impact on biocompatibility, targeted drug delivery, long shelf life, drug delivery performance, therapeutic efficacy, reduced side effects, prolonged circulation time, and targeted delivery. Enhancing nanocarrier stability requires careful design, engineering, and optimization of physical and chemical parameters. Various strategies and cutting-edge techniques employed to improve nanocarrier stability are explored, with a focus on their applications in drug delivery. By understanding the advances and challenges in nanocarrier stability, this review aims to contribute to the development and implementation of nanocarrier- based therapies in clinical settings, advancing the field of nanomedicine.

Trends on Novel Targets and Nanotechnology-Based Drug Delivery System in the Treatment of Parkinson's disease: Recent Advancement in Drug Development

Parkinson's disease (PD) is a progressive neurodegenerative disorder that impacts a significant portion of the population. Despite extensive research, an effective cure for PD remains elusive, and conventional pharmacological treatments often face limitations in efficacy and management of symptoms. There has been a lot of discussion about using nanotechnology to increase the bioavailability of small- molecule drugs to target cells in recent years. It is possible that PD treatment might become far more effective and have fewer side effects if medication delivery mechanisms were to be improved. Potential alternatives to pharmacological therapy for molecular imaging and treatment of PD may lie in abnormal proteins such as parkin, α-synuclein, leucine-rich repeat serine and threonine protein kinase 2. Published research has demonstrated encouraging outcomes when nanomedicine-based approaches are used to address the challenges of PD therapy. So, to address the present difficulties of antiparkinsonian treatment, this review outlines the key issues and limitations of antiparkinsonian medications, new therapeutic strategies, and the breadth of delivery based on nanomedicine. This review covers a wide range of subjects, including drug distribution in the brain, the efficacy of drug-loaded nano-carriers in crossing the blood-brain barrier, and their release profiles. In PD, the nano-carriers are also used. Novel techniques of pharmaceutical delivery are currently made possible by vesicular carriers, which eliminate the requirement to cross the blood-brain barrier (BBB).

The Management of Parkinson's Disease: An Overview of the Current Advancements in Drug Delivery Systems

Parkinson's disease (PD) has significantly affected a large proportion of the elderly population worldwide. According to the World Health Organization, approximately 8.5 million people worldwide are living with PD. In the United States, an estimated one million people are living with PD, with approximately 60,000 new cases diagnosed every year. Conventional therapies available for Parkinson's disease are associated with limitations such as the wearing-off effect, on-off period, episodes of motor freezing, and dyskinesia. In this review, a comprehensive overview of the latest advances in DDSs used to reduce the limitations of current therapies will be presented, and both their promising features and drawbacks will be discussed. We are also particularly interested in the technical properties, mechanism, and release patterns of incorporated drugs, as well as nanoscale delivery strategies to overcome the blood-brain barrier.

Whey Protein Isolate-Chitosan PolyElectrolyte Nanoparticles as a Drug Delivery System

Whey protein isolate (WPI), employed as a carrier for a wide range of bioactive substances, suffers from a lack of colloidal stability in physiological conditions. Herein, we developed innovative stabilized PolyElectrolyte Nanoparticles (PENs) obtained by two techniques: polyelectrolyte complexation of negatively charged WPI and positively charged chitosan (CS), and ionic gelation in the presence of polyanion tripolyphosphate (TPP). Therefore, the WPI-based core was coated with a CS-based shell and then stabilized by TPP at pH 8. The nanostructures were characterized by physiochemical methods, and their encapsulation efficiency and in vitro release were evaluated. The spherical NPs with an average size of 248.57 ± 5.00 nm and surface charge of +10.80 ± 0.43 mV demonstrated high encapsulation efficiency (92.79 ± 0.69) and sustained release of a positively charged chemotherapeutic agent such as doxorubicin (DOX). Z-average size and size distribution also presented negligible increases in size and aggregates during the three weeks. The results obtained confirm the effectiveness of the simultaneous application of these methods to improve the colloidal stability of PEN.

In-vivo time course of organ uptake and blood-brain-barrier permeation of poly(L-lactide) and poly(perfluorodecyl acrylate) nanoparticles with different surface properties in unharmed and brain-traumatized rats

Background

Traumatic brain injury (TBI) has a dramatic impact on mortality and quality of life and the development of effective treatment strategies is of great socio-economic relevance. A growing interest exists in using polymeric nanoparticles (NPs) as carriers across the blood-brain barrier (BBB) for potentially effective drugs in TBI. However, the effect of NP material and type of surfactant on their distribution within organs, the amount of the administrated dose that reaches the brain parenchyma in areas with intact and opened BBB after trauma, and a possible elicited inflammatory response are still to be clarified.

Methods

The organ distribution, BBB permeation and eventual inflammatory activation of polysorbate-80 (Tw80) and sodiumdodecylsulfate (SDS) stabilized poly(L-lactide) (PLLA) and poly(perfluorodecyl acrylate) (PFDL) nanoparticles were evaluated in rats after intravenous administration. The NP uptake into the brain was assessed under intact conditions and after controlled cortical impact (CCI).

Results

A significantly higher NP uptake at 4 and 24 h after injection was observed in the liver and spleen, followed by the brain and kidney, with minimal concentrations in the lungs and heart for all NPs. A significant increase of NP uptake at 4 and 24 h after CCI was observed within the traumatized hemisphere, especially in the perilesional area, but NPs were still found in areas away from the injury site and the contralateral hemisphere. NPs were internalized in brain capillary endothelial cells, neurons, astrocytes, and microglia. Immunohistochemical staining against GFAP, Iba1, TNFα, and IL1β demonstrated no glial activation or neuroinflammatory changes.

Conclusions

Tw80 and SDS coated biodegradable PLLA and non-biodegradable PFDL NPs reach the brain parenchyma with and without compromised BBB by TBI, even though a high amount of NPs are retained in the liver and spleen. No inflammatory reaction is elicited by these NPs within 24 h after injection. Thus, these NPs could be considered as potentially effective carriers or markers of newly developed drugs with low or even no BBB permeation.

Management of Brain Cancer and Neurodegenerative Disorders with Polymer-Based Nanoparticles as a Biocompatible Platform

The blood-brain barrier (BBB) serves as a protective barrier for the central nervous system (CNS) against drugs that enter the bloodstream. The BBB is a key clinical barrier in the treatment of CNS illnesses because it restricts drug entry into the brain. To bypass this barrier and release relevant drugs into the brain matrix, nanotechnology-based delivery systems have been developed. Given the unstable nature of NPs, an appropriate amount of a biocompatible polymer coating on NPs is thought to have a key role in reducing cellular cytotoxicity while also boosting stability. Human serum albumin (HSA), poly (lactic-co-glycolic acid) (PLGA), Polylactide (PLA), poly (alkyl cyanoacrylate) (PACA), gelatin, and chitosan are only a few of the significant polymers mentioned. In this review article, we categorized polymer-coated nanoparticles from basic to complex drug delivery systems and discussed their application as novel drug carriers to the brain.

Nanocarrier-Based Drug Delivery to Brain: Interventions of Surface Modification

Brain disorders are a prevalent and rapidly growing problem in the medical field as they adversely affect the quality of life of a human. With an increase in life expectancy, it has been reported that diseases like Alzheimer's, Parkinson's, stroke and brain tumors, along with neuropsychological disorders, are also being reported at an alarmingly high rate. Despite various therapeutic methods for treating brain disorders, drug delivery to the brain has been challenging because of a very complex Blood Brain Barrier, which precludes most drugs from entering the brain in effective concentrations. Nano-carrier-based drug delivery systems have been reported widely by researchers to overcome this barrier layer. These systems due to their small size, offer numerous advantages; however, their short residence time in the body owing to opsonization hinders their success in vivo. This review article focuses on the various aspects of modifying the surfaces of these nano-carriers with polymers, surfactants, protein, antibodies, cell-penetrating peptides, integrin binding peptides and glycoproteins such as transferrin & lactoferrin leading to enhanced residence time, desirable characteristics such as the ability to cross the blood-brain barrier (BBB), increased bioavailability in regions of the brain and targeted drug delivery.

Repositioning of drugs for Parkinson's disease and pharmaceutical nanotechnology tools for their optimization

Parkinson's disease (PD) significantly affects patients' quality of life and represents a high economic burden for health systems. Given the lack of safe and effective treatments for PD, drug repositioning seeks to offer new medication alternatives, reducing research time and costs compared to the traditional drug development strategy. This review aimed to collect evidence of drugs proposed as candidates to be reused in PD and identify those with the potential to be reformulated into nanocarriers to optimize future repositioning trials. We conducted a detailed search in PubMed, Web of Science, and Scopus from January 2015 at the end of 2021, with the descriptors "Parkinson's disease" and "drug repositioning" or "drug repurposing". We identified 28 drugs as potential candidates, and six of them were found in repositioning clinical trials for PD. However, a limitation of many of these drugs to achieve therapeutic success is their inability to cross the blood-brain barrier (BBB), as is the case with nilotinib, which has shown promising outcomes in clinical trials. We suggest reformulating these drugs in biodegradable nanoparticles (NPs) based on lipids and polymers to perform future trials. As a complementary strategy, we propose functionalizing the NPs surface by adding materials to the surface layer. Among other advantages, functionalization can promote efficient crossing through the BBB and improve the affinity of NPs towards certain brain regions. The main parameters to consider for the design of NPs targeting the central nervous system are highlighted, such as size, PDI, morphology, drug load, and Z potential. Finally, current advances in the use of NPs for Parkinson's disease are cited.

Mucoadhesive nanoemulsion enhances brain bioavailability of luteolin after intranasal administration and induces apoptosis to sh-sy5y neuroblastoma cells

Neuroblastoma is the most frequently diagnosed extracranial solid tumor in children and accounts for 7% of all childhood malignancies and 15% cancer mortality in children. Luteolin (LUT) is recognized by its anticancer activity against several types of cancer. The aim of this study was to prepare chitosan-coated nanoemulsion containing luteolin (NECh-LUT), investigate its potential for brain delivery following intranasal administration, and to evaluate its cytotoxicity against neuroblastoma cells. NECh-LUT was developed by cavitation process and characterized for its size, surface charge, encapsulation efficiency, and mucoadhesion. The developed formulation presented size 68±1 nm, zeta potential +13±1 mV, and encapsulation efficiency of 85.5±0.3%. The NECh-LUT presented nearly 6-fold higher permeation through the nasal mucosa ex vivo and prolonged LUT release up to 72 h in vitro, following Baker-Lonsdale kinetic model. The pharmacokinetic evaluation of NECh-LUT revealed a 10-fold increase in drug half-life and a 4.4 times enhancement in LUT biodistribution in brain tissue after intranasal administration of single-dose. In addition, NECh-LUT inhibited the growth of neuroblastoma cells after 24, 48 and 72 h in concentrations starting from 2 µM. The NECh-LUT developed for intranasal administration proved to be a promising alternative for brain delivery of LUT, and a viable option for the treatment of neuroblastoma.

The therapeutic benefits of intravenously administrated nanoparticles in stroke and age-related neurodegenerative diseases

The mean global lifetime risk of neurological disorders such as stroke, Alzheimer's disease (AD), and Parkinson's disease (PD) has shown a large effect on economy and society.Researchersare stillstruggling to find effective drugs to treatneurological disordersand drug delivery through the blood-brain barrier (BBB) is a major challenge to be overcome. The BBB is a specialized multicellular barrier between the peripheral blood circulation and the neural tissue. Unique and selective features of the BBB allow it to tightly control brain homeostasis as well as the movement of ions and molecules. Failure in maintaining any of these substances causes BBB breakdown and subsequently enhances neuroinflammation and neurodegeneration.BBB disruption is evident in many neurologicalconditions.Nevertheless, the majority of currently available therapies have tremendous problems for drug delivery into the impaired brain. Nanoparticle (NP)-mediated drug delivery has been considered as a profound substitute to solve this problem. NPs are colloidal systems with a size range of 1-1000 nm whichcan encapsulate therapeutic payloads, improve drug passage across the BBB, and target specific brain areas in neurodegenerative/ischemic diseases. A wide variety of NPs has been displayed for the efficient brain delivery of therapeutics via intravenous administration, especially when their surfaces are coated with targeting moieties. Here, we discuss recent advances in the development of NP-based therapeutics for the treatment of stroke, PD, and AD as well as the factors affecting their efficacy after systemic administration.

Potential role of chitosan, PLGA and iron oxide nanoparticles in Parkinson’s disease therapy

Background

Parkinson's disease (PD) is a debilitating disease that alters an individual's functionality. Parkinsonism is a complex symptom consisting of numerous motor and non-motor features, and although several disorders are responsible, PD remains the most important. Several theories have been proposed for the characteristic pathological changes, the most important of which is the loss of dopaminergic neurons associated with a reduced ability to perform voluntary movements. Many drugs have been developed over the years to treat the condition and prevent its progression, but drug delivery is still a challenge due to the blood–brain barrier, which prevents the passage of drugs into the central nervous system. However, with the advances in nanotechnology in the medical field, there is growing hope of overcoming this challenge.

Summary

Our review highlights the potential role of three commonly studied nanoparticles in laboratory-induced animal models of PD: chitosan, PLGA, and iron oxide nanoparticles as potential PD therapy in humans.

Biocompatible mucoadhesive nanoparticles for brain targeting of ropinirole hydrochloride: Formulations, radiolabeling and biodistribution

Two nanoformulations with mucoadhesive properties and brain-targeting mechanisms were designed to deliver the anti-Parkinson's drug, ropinirole hydrochloride (RH). In the first formulation, RH and the amphiphilic block copolymer methoxy poly(ethylene glycol)-b-poly(caprolactone) were assembled in a core-shell morphology followed by coating with a mucoadhesive chitosan outer layer producing a multilayer vehicle (MLV). In the second formulation, RH was encapsulated during the polyelectrolyte complexation of two natural polymers, chitosan and alginate producing RH-loaded chitosan-alginate polyelectrolyte (PEC) nanocomplex. Conditions of each formulation were adopted for optimal drug loading. Physico-chemical characterization of the prepared formulations (particle size, polydispersity index and zeta-potential) exhibited stable monodispersed nanoparticles. RH was radiolabeled by I-131 radiotracer in a high-radiochemical yield. Biodistribution and brain targeting of RH from the prepared formulations were studied after administration of ¹³¹ I-RH-loaded nanoparticles to albino mice via intranasal and intravenous routs. Elevated brain radioactivity was detected post IN administration of (¹³¹ I-RH/PCL-PEG/CS) nanoparticles and (¹³¹ I-RH/CS-ALG) nanoparticles comparing with the IN administrated RH solutions (C_max  = 2.8 ± 0.3, 2 ± 0.3, 0.93 ± 0.03% radioactivity/g, 1 h post administration, respectively). This demonstrated that a relatively high-brain targeting could be achieved via intranasal route of administration of RH-loaded nanoparticles. The proposed models are further potential for application to deliver many other brain-targeting therapeutics.

Drug Nanocrystals: Focus on Brain Delivery from Therapeutic to Diagnostic Applications

The development of new drugs is often hindered by low solubility in water, a problem common to nearly 90% of natural and/or synthetic molecules in the discovery pipeline. Nanocrystalline drug technology involves the reduction in the bulk particle size down to the nanosize range, thus modifying its physico-chemical properties with beneficial effects on drug bioavailability. Nanocrystals (NCs) are carrier-free drug particles surrounded by a stabilizer and suspended in an aqueous medium. Due to high drug loading, NCs maintain a potent therapeutic concentration to produce desirable pharmacological action, particularly useful in the treatment of central nervous system (CNS) diseases. In addition to the therapeutic purpose, NC technology can be applied for diagnostic scope. This review aims to provide an overview of NC application by different administration routes, especially focusing on brain targeting, and with a particular attention to therapeutic and diagnostic fields. NC therapeutic applications are analyzed for the most common CNS pathologies (i.e., Parkinson's disease, psychosis, Alzheimer's disease, etc.). Recently, a growing interest has emerged from the use of colloidal fluorescent NCs for brain diagnostics. Therefore, the use of NCs in the imaging of brain vessels and tumor cells is also discussed. Finally, the clinical effectiveness of NCs is leading to an increasing number of FDA-approved products, among which the NCs approved for neurological disorders have increased.

Nanotechnology-based drug delivery for the treatment of CNS disorders

Approximately 6.8 million people die annually because of problems related to the central nervous system (CNS), and out of them, approximately 1 million people are affected by neurodegenerative diseases that include Alzheimer's disease, multiple sclerosis, epilepsy, and Parkinson's disease. CNS problems are a primary concern because of the complexity of the brain. There are various drugs available to treat CNS disorders and overcome problems with toxicity, specificity, and delivery. Barriers like the blood-brain barrier (BBB) are a challenge, as they do not allow therapeutic drugs to cross and reach their target. Researchers have been searching for ways to allow drugs to pass through the BBB and reach the target sites. These problems highlight the need of nanotechnology to alter or manipulate various processes at the cellular level to achieve the desired attributes. Due to their nanosize, nanoparticles are able to pass through the BBB and are an effective alternative to drug administration and other approaches. Nanotechnology has the potential to improve treatment and diagnostic techniques for CNS disorders and facilitate effective drug transfer. With the aid of nanoengineering, drugs could be modified to perform functions like transference across the BBB, altering signaling pathways, targeting specific cells, effective gene transfer, and promoting regeneration and preservation of nerve cells. The involvement of a nanocarrier framework inside the delivery of several neurotherapeutic agents used in the treatment of neurological diseases is reviewed in this study.

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.

PLGA-Based Nanoparticles for Neuroprotective Drug Delivery in Neurodegenerative Diseases

Treatment of neurodegenerative diseases has become one of the most challenging topics of the last decades due to their prevalence and increasing societal cost. The crucial point of the non-invasive therapeutic strategy for neurological disorder treatment relies on the drugs' passage through the blood-brain barrier (BBB). Indeed, this biological barrier is involved in cerebral vascular homeostasis by its tight junctions, for example. One way to overcome this limit and deliver neuroprotective substances in the brain relies on nanotechnology-based approaches. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) are biocompatible, non-toxic, and provide many benefits, including improved drug solubility, protection against enzymatic digestion, increased targeting efficiency, and enhanced cellular internalization. This review will present an overview of the latest findings and advances in the PLGA NP-based approach for neuroprotective drug delivery in the case of neurodegenerative disease treatment (i.e., Alzheimer's, Parkinson's, Huntington's diseases, Amyotrophic Lateral, and Multiple Sclerosis).

Importance of Nanoparticles for the Delivery of Antiparkinsonian Drugs

Parkinson's disease (PD) affects around ten million people worldwide and is considered the second most prevalent neurodegenerative disease after Alzheimer's disease. In addition, there is a higher risk incidence in the elderly population. The main PD hallmarks include the loss of dopaminergic neurons and the development of Lewy bodies. Unfortunately, motor symptoms only start to appear when around 50-70% of dopaminergic neurons have already been lost. This particularly poses a huge challenge for early diagnosis and therapeutic effectiveness. Actually, pharmaceutical therapy is able to relief motor symptoms, but as the disease progresses motor complications and severe side-effects start to appear. In this review, we explore the research conducted so far in order to repurpose drugs for PD with the use of nanodelivery systems, alternative administration routes, and nanotheranostics. Overall, studies have demonstrated great potential for these nanosystems to target the brain, improve drug pharmacokinetic profile, and decrease side-effects.

Natural Polysaccharide Carriers in Brain Delivery: Challenge and Perspective

Targeted drug delivery systems represent valuable tools to enhance the accumulation of therapeutics in the brain. Here, the presence of the blood brain barrier strongly hinders the passage of foreign substances, often limiting the effectiveness of pharmacological therapies. Among the plethora of materials used for the development of these systems, natural polysaccharides are attracting growing interest because of their biocompatibility, muco-adhesion, and chemical versatility which allow a wide range of carriers with tailored physico-chemical features to be synthetized. This review describes the state of the art in the field of targeted carriers based on natural polysaccharides over the last five years, focusing on the main targeting strategies, namely passive and active transport, stimuli-responsive materials and the administration route. In addition, in the last section, the efficacy of the reviewed carriers in each specific brain diseases is summarized and commented on in terms of enhancement of either blood brain barrier (BBB) permeation ability or drug bioavailability in the brain.

Nanoparticles for drug delivery in Parkinson's disease

Although effective symptomatic treatments for Parkinson's disease (PD) have been available for some time, efficient and well-controlled drug delivery to the brain has proven to be challenging. The emergence of nanotechnology has created new opportunities not only for improving the pharmacokinetics of conventional therapies but also for developing novel treatment approaches and disease modifying therapies. Several exciting strategies including drug carrier nanoparticles targeting specific intracellular pathways and structural reconformation of tangled proteins as well as introducing reprogramming genes have already shown promise and are likely to deliver more tailored approaches to the treatment of PD in the future. This paper reviews the role of nanoparticles in PD including a discussion of both their composition and functional capacity as well as their potential to deliver better therapeutic agents.

Overcoming the Blood-Brain Barrier: Functionalised Chitosan Nanocarriers

The major impediment to the delivery of therapeutics to the brain is the presence of the blood-brain barrier (BBB). The BBB allows for the entrance of essential nutrients while excluding harmful substances, including most therapeutic agents; hence, brain disorders, especially tumours, are very difficult to treat. Chitosan is a well-researched polymer that offers advantageous biological and chemical properties, such as mucoadhesion and the ease of functionalisation. Chitosan-based nanocarriers (CsNCs) establish ionic interactions with the endothelial cells, facilitating the crossing of drugs through the BBB by adsorptive mediated transcytosis. This process is further enhanced by modifications of the structure of chitosan, owing to the presence of reactive amino and hydroxyl groups. Finally, by permanently binding ligands or molecules, such as antibodies or lipids, CsNCs have showed a boosted passage through the BBB, in both in vivo and in vitro studies which will be discussed in this review.

Revisiting the blood-brain barrier: A hard nut to crack in the transportation of drug molecules

Barriers are the hallmark of a healthy physiology, blood-brain barrier (BBB) being a tough nut to crack for most of the antigens and chemical substances. The presence of tight junctions plays a remarkable role in defending the brain from antigenic and pathogenic attacks. BBB constitutes a diverse assemblage of multiple physical and chemical barriers that judiciously restrict the flux of blood solutes into and out of the brain. Restrictions through the paracellular pathway and the tight junctions between intercellular clefts, together create well regulated metabolic and transport barricades, critical to brain pathophysiology. The brain being impermeable to many essential metabolites and nutrients regulates transportation via specialized transport systems across the endothelial abluminal and luminal membranes. The epithelial cells enveloping capillaries of the choroid plexus regulates the transport of complement, growth factors, hormones, microelements, peptides and trace elements into ventricles. Nerve terminals, microglia, and pericytes associated with the endothelium support barrier induction and function, ensuring an optimally stable ionic microenvironment that facilitates neurotransmission, orchestrated by multiple ion channels (Na⁺, K⁺ Mg²⁺, Ca²⁺) and transporters. Brain pathology which can develop due to genetic mutations or secondary to other cerebrovascular, neurodegenerative diseases can cause aberration in the microvasculature of CNS which is the uniqueness of BBB. This can also alter BBB permeation and result in BBB breakdown and other neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. The concluding section outlines contemporary trends in drug discovery, focusing on molecular determinants of BBB permeation and novel drug-delivery systems, such as dendrimers, liposomes, nanoparticles, nanogels, etc.

Application of computational tools for the designing of Oleuropein loaded nanostructured lipid carrier for brain targeting through nasal route

PURPOSE

Meningitis is an inflammation of meninges encircled the brain and spinal cord. Currently it can be treated with second generation cephalosporins which were ended up with an unresolvable problem called Multi Drug Resistance (MDR). Hence, there is a need to develop a better herbal molecule to conflict the MDR.

METHODS

Hot Blanching technique followed by ultra sound assisted extraction using bio-solvent aqueous glycerol was used to extract OLE from olive leaves. QbD tool was applied to predict the interactions between Critical Material Attributes (Ratio of solid Lipid X₁, Concentration of Surfactant X₂) and Critical Process Parameters (Homogenization Time X₃) on Critical Quality Attributes (CQA, Particle Size Y₁, Zeta Potential Y₂, and Entrapment Efficiency Y₃). Particulate characteristics were evaluated and Invivo pharmacokinetic study was done in albino Wistar rats by IV and IN route of administration.

RESULTS

Thermal studies reflect the formation of low ordered crystalline structure of lipid matrix which offers higher encapsulation of drug in NLC than physical mixture. CMA and CPP show significant effect on CQA and method operable design range was developed. Histo-pathological studies confirms that there is no signs of toxicity and in-vitro drug release studies reveals a rapid release of a drug initially followed by prolonged release of oleuropein upto 24 h. The absolute bioavailability of drug loaded NLC in brain was higher in IN route compared to NLC administered by IV route.

CONCLUSIONS

In a nutshell, challenges offered by the hydrophilic OLE for brain targeting can be minimized through lipidic nature of NLC. Graphical Abstract.

Intranasal delivery of mucoadhesive nanocarriers: a viable option for Parkinson's disease treatment?

Introduction: Intranasal drug delivery is a largely unexplored, promising approach for the treatment of various neurological disorders. However, due to the challenging constraints available in the pathway of nose-to-brain delivery, finding an effective treatment for Parkinsonism is still an impending mission for research workers. This warrants development of novel treatment alternatives for Parkinson's disease (PD). Intranasal delivery of mucoadhesive nanocarriers is one such novel approach which might help in curbing the glitches associated with the currently available therapy.Areas covered: This review summarizes the evidences supporting nose-to-brain delivery of polymer-based mucoadhesive nanocarriers for the treatment of PD. A concise insight into the lipid-based mucoadhesive nanocarriers has also been presented. The recent researches have been compiled pertaining to the use of mucoadhesive nanocarrriers for improving the treatment outcomes of PD via intranasal drug delivery.Expert opinion: Although the use of nanocarrier-based strategies for site-specific delivery via intranasal route has proven effective, the magnitude of improvement remains moderate resulting in limited translation from industry to the market. Comprehensive understanding of the mucoadhesive polymer, its characteristics and mechanisms involved for an effective nose-to-brain uptake of the drug is a promising avenue to develop novel formulations for effective management of Parkinson disease.

Chitosan-Based Nanocarriers for Nose to Brain Delivery

In the treatment of brain diseases, most potent drugs that have been developed exhibit poor therapeutic outcomes resulting from the inability of a therapeutic amount of the drug to reach the brain. These drugs do not exhibit targeted drug delivery mechanisms, resulting in a high concentration of the drugs in vital organs leading to drug toxicity. Chitosan (CS) is a natural-based polymer. It has unique properties such as good biodegradability, biocompatibility, mucoadhesive properties, and it has been approved for biomedical applications. It has been used to develop nanocarriers for brain targeting via intranasal administration. Nanocarriers such as nanoparticles, in situ gels, nanoemulsions, and liposomes have been developed. In vitro and in vivo studies revealed that these nanocarriers exhibited enhanced drug uptake to the brain with reduced side effects resulting from the prolonged contact time of the nanocarriers with the nasal mucosa, the surface charge of the nanocarriers, the nano size of the nanocarriers, and their capability to stretch the tight junctions within the nasal mucosa. The aforementioned unique properties make chitosan a potential material for the development of nanocarriers for targeted drug delivery to the brain. This review will focus on chitosan-based carriers for brain targeting.

Chitosan-based (Nano)materials for Novel Biomedical Applications

Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Multiple perspectives of the proposed antibacterial effect and mode of action of chitosan-based nanomaterials are reviewed. Chitosan is presented as an ideal biomaterial for antimicrobial wound dressings that can either be fabricated alone in its native form or upgraded and incorporated with antibiotics, metallic antimicrobial particles, natural compounds and extracts in order to increase the antimicrobial effect. Since chitosan and its derivatives can enhance drug permeability across the blood-brain barrier, they can be also used as effective brain drug delivery carriers. Some of the recent chitosan formulations for brain uptake of various drugs are presented. The use of chitosan and its derivatives in other biomedical applications is also briefly discussed.