Nose-To-Brain Delivery of PLGA-Diazepam Nanoparticles

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

Background

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

Methods

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

Results

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

Conclusion

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

Intranasal administration enhances size-dependent pulmonary phagocytic uptake of poly(lactic-co-glycolic acid) nanoparticles

BACKGROUND

Nanoparticles exhibit distinct behaviours within the body, depending on their physicochemical properties and administration routes. However, in vivo behaviour of poly(lactic-co-glycolic acid) (PLGA) nanoparticles, especially when administered nasally, remains unexplored; furthermore, there is a lack of comparative analysis of uptake efficiency among different administration routes. Therefore, here, we aimed to comprehensively investigate the real-time in vivo behaviour of PLGA nanoparticles across various administration routes. PLGA-NH2 nanoparticles of three sizes were synthesised using an oil-in-water single-emulsion method. We assessed their uptake by murine macrophage RAW264.7 cells using fluorescence microscopy. To enable real-time tracking, we conjugated p-SCN-Bn-deferoxamine to PLGA-NH2 nanoparticles and further radiolabelled them with 89Zr-oxalate before administration to mice via different routes. Nanoparticle internalisation by lung immune cells was monitored using fluorescence-activated cell sorting analysis.

RESULTS

The nanoparticle sizes were 294 ± 2.1 (small), 522.5 ± 5.58 (intermediate), and 850 ± 18.52 nm (large). Fluorescent labelling did not significantly alter the nanoparticle size and charge. The level of uptake of small and large nanoparticles by RAW264.7 cells was similar, with phagocytosis inhibition primarily reducing the internalisation of large particles. Positron emission tomography revealed that intranasal delivery resulted in the highest and most targeted pulmonary uptake, whereas intravenous administration led to accumulation mainly in the liver and spleen. Nasal delivery of large nanoparticles resulted in enhanced uptake by myeloid immune cells relative to lymphoid cells, whereas dendritic cell uptake initially peaked but declined over time.

CONCLUSIONS

Our study provides valuable insights into advancing nanomedicine and drug delivery, with the potential for expanding the clinical applications of nanoparticles.

Challenges and prospects in geriatric epilepsy treatment: the role of the blood-brain barrier in pharmacotherapy and drug delivery

The blood-brain barrier (BBB) is pivotal in maintaining neuronal physiology within the brain. This review delves into the alterations of the BBB specifically in the context of geriatric epilepsy. We examine how age-related changes in the BBB contribute to the pathogenesis of epilepsy in the elderly and present significant challenges in pharmacotherapy. Subsequently, we evaluate recent advancements in drug delivery methods targeting the BBB, as well as alternative approaches that could bypass the BBB's restrictive nature. We particularly highlight the use of neurotropic viruses and various synthetic nanoparticles that have been investigated for delivering a range of antiepileptic drugs. Additionally, the advantage and limitation of these diverse delivery methods are discussed. Finally, we analyze the potential efficacy of different drug delivery approaches in the treatment of geriatric epilepsy, aiming to provide insights into more effective management of this condition in the elderly population.

Tadpole-Like Anisotropic Polymer/Lipid Janus Nanoparticles for Nose-to-Brain Drug Delivery: Importance of Geometry, Elasticity on Mucus-Penetration Ability

Asymmetric geometry (aspect ratio >1), moderate stiffness (i.e., semielasticity), large surface area, and low mucoadhesion of nanoparticles are the main features to reach the brain by penetrating across the nasal mucosa. Herein, a new application has been presented for the use of multifunctional Janus nanoparticles (JNPs) with controllable geometry and size as a nose-to-brain (N2B) delivery system by changing proportions of Precirol ATO 5 and polycaprolactone compartments and other operating conditions. To bring to light the N2B application of JNPs, the results are presented in comparison with polymer and solid lipid nanoparticles, which are frequently used in the literature regarding their biopharmaceutical aspects: mucoadhesion and permeability through the nasal mucosa. The morphology and geometry of JPs were observed via cryogenic-temperature transmission electron microscopy images, and their particle sizes were verified by dynamic light scattering, atomic force microscopy, and scanning electron microscopy. Although all NPs showed penetration across the mucus barrier, the best increase in penetration was observed with asymmetric and semielastic JNPs, which have low interaction ability with the mucus layer. This study presents a new and promising field of application for a multifunctional system suitable for N2B delivery, potentially benefiting the treatment of brain tumors and other central nervous system diseases.

Nose-to-Brain (N2B) Delivery: An Alternative Route for the Delivery of Biologics in the Management and Treatment of Central Nervous System Disorders

In recent years, there have been a growing number of small and large molecules that could be used to treat diseases of the central nervous system (CNS). Nose-to-brain delivery can be a potential option for the direct transport of molecules from the nasal cavity to different brain areas. This review aims to provide a compilation of current approaches regarding drug delivery to the CNS via the nose, with a focus on biologics. The review also includes a discussion on the key benefits of nasal delivery as a promising alternative route for drug administration and the involved pathways or mechanisms. This article reviews how the application of various auxiliary agents, such as permeation enhancers, mucolytics, in situ gelling/mucoadhesive agents, enzyme inhibitors, and polymeric and lipid-based systems, can promote the delivery of large molecules in the CNS. The article also includes a discussion on the current state of intranasal formulation development and summarizes the biologics currently in clinical trials. It was noted that significant progress has been made in this field, and these are currently being applied to successfully transport large molecules to the CNS via the nose. However, a deep mechanistic understanding of this route, along with the intimate knowledge of various excipients and their interactions with the drug and nasal physiology, is still necessary to bring us one step closer to developing effective formulations for nasal-brain drug delivery.

Nanotechnology prospects in brain therapeutics concerning gene-targeting and nose-to-brain administration

Neurological diseases are one of the most pressing issues in modern times worldwide. It thus possesses explicit attention from researchers and medical health providers to guard public health against such an expanding threat. Various treatment modalities have been developed in a remarkably short time but, unfortunately, have yet to lead to the wished-for efficacy or the sought-after clinical improvement. The main hurdle in delivering therapeutics to the brain has always been the blood-brain barrier which still represents an elusive area with lots of mysteries yet to be solved. Meanwhile, nanotechnology has emerged as an optimistic platform that is potentially holding the answer to many of our questions on how to deliver drugs and treat CNS disorders using novel technologies rather than the unsatisfying conventional old methods. Nanocarriers can be engineered in a way that is capable of delivering a certain therapeutic cargo to a specific target tissue. Adding to this mind-blowing nanotechnology, the revolutionizing gene-altering biologics can have the best of both worlds, and pave the way for the long-awaited cure to many diseases, among those diseases thus far are Alzheimer's disease (AD), brain tumors (glioma and glioblastoma), Down syndrome, stroke, and even cases with HIV. The review herein collects the studies that tested the mixture of both sciences, nanotechnology, and epigenetics, in the context of brain therapeutics using three main categories of gene-altering molecules (siRNA, miRNA, and CRISPR) with a special focus on the advancements regarding the new favorite, intranasal route of administration.

Optimizing Absorption for Intranasal Delivery of Drugs Targeting the Central Nervous System Using Alkylsaccharide Permeation Enhancers

Intranasal delivery of drugs offers several potential benefits related to ease of delivery, rapid onset, and patient experience, which may be of particular relevance to patients with central nervous system (CNS) conditions who experience acute events. Intranasal formulations must be adapted to address anatomical and physiological characteristics of the nasal cavity, including restricted dose volume, limited surface area, and barriers to mucosal absorption, in addition to constraints on the absorption window due to mucociliary clearance. Development of an effective formulation may utilize strategies including the addition of excipients to address the physicochemical properties of the drug within the constraints of nasal delivery. Dodecyl maltoside (DDM) and tetradecyl maltoside are alkylsaccharide permeation enhancers with well-established safety profiles, and studies have demonstrated transiently improved absorption and favorable bioavailability of several compounds in preclinical and clinical trials. Dodecyl maltoside is a component of three US Food and Drug Administration (FDA)-approved intranasal medications: diazepam for the treatment of seizure cluster in epilepsy, nalmefene for the treatment of acute opioid overdose, and sumatriptan for the treatment of migraine. Another drug product with DDM as an excipient is currently under FDA review, and numerous investigational drugs are in early-stage development. Here, we review factors related to the delivery of intranasal drugs and the role of alkylsaccharide permeation enhancers in the context of approved and future intranasal formulations of drugs for CNS conditions.

Biomaterials-Enhanced Intranasal Delivery of Drugs as a Direct Route for Brain Targeting

Intranasal (IN) drug delivery is a non-invasive and effective route for the administration of drugs to the brain at pharmacologically relevant concentrations, bypassing the blood-brain barrier (BBB) and minimizing adverse side effects. IN drug delivery can be particularly promising for the treatment of neurodegenerative diseases. The drug delivery mechanism involves the initial drug penetration through the nasal epithelial barrier, followed by drug diffusion in the perivascular or perineural spaces along the olfactory or trigeminal nerves, and final extracellular diffusion throughout the brain. A part of the drug may be lost by drainage through the lymphatic system, while a part may even enter the systemic circulation and reach the brain by crossing the BBB. Alternatively, drugs can be directly transported to the brain by axons of the olfactory nerve. To improve the effectiveness of drug delivery to the brain by the IN route, various types of nanocarriers and hydrogels and their combinations have been proposed. This review paper analyzes the main biomaterials-based strategies to enhance IN drug delivery to the brain, outlining unsolved challenges and proposing ways to address them.

Nanonized carbamazepine for nose-to-brain delivery: pharmaceutical formulation development

Epilepsy is one of the most common neurological disorders in the world. The therapeutic treatment is challenging since conventional drugs have limited efficacy and several side effects that impair patient management. Efforts are being made to find innovative strategies to control epileptic seizures. Intranasal administration provides a convenient route to deliver the drug to the brain. Carbamazepine (CBZ) is an anticonvulsant characterized by poor water solubility, nanonization can improve its bioavailability. Therefore, the design of CBZ nanocrystals (NCs) was assessed to obtain a formulation suitable for nose-to-brain delivery. CBZ NCs were prepared by sonoprecipitation following the Quality by Design approach identifying the impact of process and formulation variables on the critical quality attributes of the final product. The formulation was characterized by a technological point of view (thermotropic behavior, crystallinity, morphology, mucoadhesive strength). Response surface methodology was a reliable tool (error % 2.6) to optimize CBZ NCs with size ≤300 nm. Incubation of CBZ NCs in artificial cerebrospinal fluid at 37 °C did not promote aggregation and degradation phenomena. Preliminary biological studies revealed the biocompatibility of CBZ NCs towards Olfactory Ensheating Cells. The suspension was successfully converted into a powder. The highly concentrated formulation can be obtained, providing the possibility to administer the maximum dose of the drug in the lowest volume.

Translational Considerations in the Development of Intranasal Treatments for Epilepsy

Epilepsy is a common and serious neurological disorder, to which a high proportion of patients continue to be considered "drug-resistant", despite the availability of a host of anti-seizure drugs. Investigation into new treatment strategies is therefore of great importance. One such strategy is the use of the nose to deliver drugs directly to the brain with the help of pharmaceutical formulation to overcome the physical challenges presented by this route. The following review explores intranasal delivery of anti-seizure drugs, covering the link between the nose and seizures, pathways from the nose to the brain, current formulations in clinical use, animal seizure models and their proposed application in studying intranasal treatments, and a critical discussion of relevant pre-clinical studies in the literature.

QbD-based rivastigmine tartrate-loaded solid lipid nanoparticles for enhanced intranasal delivery to the brain for Alzheimer's therapeutics

Alzheimer's disease (AD) is a neurodegenerative disease that affects a wide range of populations and is the primary cause of death in various countries. The treatment of AD is still restricted to oral conventional medicines that act only superficially. Fabrication of intranasal solid lipid nanoparticulate system for the uptake of therapeutic agents will act as a convincing approach with limited off-site toxicity and increased pharmacological activity. The objective of this study was to formulate, optimize, and evaluate the efficiency of rivastigmine tartrate (RT)-loaded intranasal solid lipid nanoparticles (SLNs) employing the solvent-evaporation diffusion method. To optimize the formulation parameters, the central composite design (CCD) was used. Lipid concentration (X1) and surfactant concentration (X2) were considered to be independent variables, while particle size (Y1), percentage entrapment efficiency (Y2), and percentage drug release (Y3) were considered as responses. The solid lipid was glyceryl monostearate, while the surfactant was polysorbate 80. The optimized formulation has a particle size of 110.2 nm, % entrapment efficiency of 82.56%, and % drug release of 94.86%. The incompatibility of drug excipients was established by differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). Nasal histopathology tests on sheep mucosa revealed that the developed SLNs were safe to utilize for intranasal delivery with no toxicity. Ex vivo permeation investigations revealed that the flux and diffusion coefficients for RT solid lipid nanoparticles and RT solution were 3.378 g/cm2 /h and 0.310-3 cm2 /h, respectively. Stability studies demonstrated that the developed SLNs were stable when stored under various storage conditions. The viability and vitality of adopting a lipid particle delivery system for improved bioavailability via the intranasal route were also established in the in vivo pharmacokinetic investigations. According to the histopathological and pharmacokinetic investigations, the developed formulations were safe, non-lethal, efficient, and robust. These results suggest the potentiality provided by rivastigmine tartrate-loaded solid lipid nanoparticles for nasal delivery.

Intranasally administered melatonin core-shell polymeric nanocapsules: A promising treatment modality for cerebral ischemia

AIMS

The neurohormone melatonin (MEL) has been reported as a promising neuroprotective molecule, however it suffers pharmaceutical limitations such as poor solubility and low bioavailability, which hinder its pharmacological and clinical potential. In the current work, MEL was loaded in core-shell nanocarrier system; polymeric nanocapsules (PNCs), and assessed for its potential in cerebral ischemia reperfusion injury rat model when administered intranasally.

KEY FINDINGS

Adopting a D-optimal factorial design, MEL-PNCs were successfully formulated using the nanoprecipitation technique. MEL-PNCs exhibited a particle size ranging from 143.5 to 444 nm, negative zeta potential values ranging from -24.2 to -38.7 mV, cumulative release % for MEL ranging from 36.79 to 41.31 % over 8 h period, with overall good storage properties. The selected MEL-PNCs formulation displayed 8-fold higher permeation than the drug solution across sheep nasal mucosa. MEL-PNCs administered intranasally decreased oxidative stress and hippocampal inflammation, and the histological examination revealed the significant restoration of hippocampal neurons.

SIGNIFICANCE

MEL-PNCs administered intranasally could be a promising treatment modality in brain ischemia.

Intranasal Delivery of Functionalized Polymeric Nanomaterials to the Brain

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

Intranasal Delivery of Darunavir-Loaded Mucoadhesive In Situ Gel: Experimental Design, In Vitro Evaluation, and Pharmacokinetic Studies

The clinical efficacy of antiretroviral therapy in NeuroAIDS is primarily limited by the low perfusion of the drug to the brain. The objective of the current investigation was to design and develop an in situ mucoadhesive gel loaded with darunavir to assess the feasibility of brain targeting through the intranasal route. Preliminary batches (F1−F9) were prepared and evaluated for various pharmaceutical characteristics. A full factorial design of the experiment was applied to optimize and assess the effect of two influencing variables (Carbopol 934P (X1) and Poloxamer 407 (X2)) on the response effects (gelation temperature (Y1) and % drug release (Y2) at 8 h). The data demonstrate that both influencing variables affect the response variables significantly (p < 0.05). The optimized formulation (F7) exhibited favorable rheological properties, adequate mucoadhesion, sustained drug release, and greater permeation across the nasal mucosa. An in vitro ciliotoxicity study confirms the nontoxicity of the optimized in situ gel (D7) on the nasal mucosa. An in vivo pharmacokinetic study in rats was performed to assess drug targeting to the brain following the nasal application of the selected in situ gel (D7). Significantly higher (p < 0.0001) Cmax (~4-fold) and AUC0-α (~3.5-fold) values were noticed in the brain after nasal application, as compared to the intravenous route. However, less systemic exposure to darunavir was noticed with nasal therapy, which confirms the low absorption of the drug into the central compartment. Overall, the data here demonstrate that the optimized in situ mucoadhesive nasal gel is effective in targeting darunavir to the brain by the nasal route and could be a viable option for the treatment of NeuroAIDS.

In vitro & In vivo evaluations of PLGA nanoparticle based combinatorial drug therapy for Baclofen and Lamotrigine for neuropathic pain management

AIM

Baclofen and Lamotrigine via PLGA nanoparticles were developed for nose-to-brain delivery for treatment of Neuropathic pain.

METHODS

Nanoparticles were prepared using modified nano-precipitation method. The prepared NPs were characterized and further in vitro and in vivo studies were performed.

RESULTS

The Bcf-Ltg-PLGA-NPs were ∼177.7nm with >75%(w/w) drugs encapsulated. In vitro dissolution studies suggested zero-order release profiles following Korsmeyer-Peppas model. In vitro cytotoxicity and staining studies on mammalian cells showed dose dependant cytotoxicity where nanoparticles were significantly less toxic(>95% cell-viability). ELISA studies on RAW-macrophages showed Bcf-Ltg-PLGA-NPs as potential pro-inflammatory-cytokines inhibitor. In vivo gamma-scintigraphy studies on rats showed intra-nasal administration of ^99mTc-Bcf-Ltg-PLGA-NPs showed C_max 3.6%/g at T_max=1.5h with DTE% as 191.23% and DTP% = 38.61% in brain. Pharmacodynamics evaluations on C57BL/6J mice showed significant reduction in licks/bites during inflammation induced phase II pain.

CONCLUSION

The findings concluded that combination of these drugs into single nanoparticle-based formulation has potential for pain management.

Restoration of olfactory dysfunctions by nanomaterials and stem cells-based therapies: Current status and future perspectives

Dysfunction in the olfactory system of a person can have adverse effects on their health and quality of life. It can even increase mortality among individuals. Olfactory dysfunction is related to many factors, including post-viral upper respiratory infection, head trauma, and neurodegenerative disorders. Although some clinical therapies such as steroids and olfactory training are already available, their effectiveness is limited and controversial. Recent research in the field of therapeutic nanoparticles and stem cells has shown the regeneration of dysfunctional olfactory systems. Thus, we are motivated to highlight these regenerative approaches. For this, we first introduce the anatomical characteristics of the olfactory pathway, then detail various pathological factors related to olfactory dysfunctions and current treatments, and then finally discuss the recent regenerative endeavors, with particular focus on nanoparticle-based drug delivery systems and stem cells. This review offers insights into the development of future therapeutic approaches to restore and regenerate dysfunctional olfactory systems.

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.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

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

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

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

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

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

Intranasal delivery of phenytoin-loaded nanoparticles to the brain suppresses pentylenetetrazol-induced generalized tonic clonic seizures in an epilepsy mouse model

In this work we describe the preparation and characterization of lecithin-chitosan nanoparticles (L₁₀C_i⁺), and investigate their ability to deliver the anti-epileptic drug phenytoin (PHT) to mouse brain following intranasal (IN) administration. L₁₀C_i⁺ were retained in the nasal cavity compared to PHT in PEG200 solution (PHT/PEG), which suffered immediate nasal drainage. PHT was detected in the brain after 5 min of IN administration reaching a maximum of 11.84 ± 2.31 %ID g^-1 after 48 hours. L₁₀C_i⁺ were associated with a higher brain/plasma ratio (C_b/p) compared to the experimental control comprising free PHT injected via the intraperitoneal route (PHT-IP) across all tested time points. Additionally, L₁₀C_i⁺ led to lower PHT accumulation in the liver and spleen compared to PHT-IP, which is vital for lowering the systemic side effects of PHT. The relatively high drug targeting efficiency (DTE%) of 315.46% and the drug targeting percentage (DTP%) of 68.29%, combined with the increasing anterior-to-posterior gradient of PHT in the brain confirmed the direct nose-to-brain transport of PHT from L₁₀C_i⁺. Electroencephalogram (EEG) analysis was used to monitor seizure progression. L₁₀C_i⁺ resulted in a complete seizure suppression after 4 hours of administration, and this inhibition persisted even with an 8-fold reduction of the encapsulated dose compared to the required PHT-IP dose to achieve a similar inhibitory effect due to systemic loss. The presented findings confirm the possibility of using L₁₀C_i⁺ as a non-invasive delivery system of PHT for the management of epilepsy using reduced doses of PHT.

Optimized Rivastigmine Nanoparticles Coated with Eudragit for Intranasal Application to Brain Delivery: Evaluation and Nasal Ciliotoxicity Studies

Rivastigmine, a reversible cholinesterase inhibitor, is frequently indicated in the management of demented conditions associated with Alzheimer disease. The major hurdle of delivering this drug through the oral route is its poor bioavailability, which prompted the development of novel delivery approaches for improved efficacy. Due to numerous beneficial properties associated with nanocarriers in the drug delivery system, rivastigmine nanoparticles were fabricated to be administer through the intranasal route. During the development of the nanoparticles, preliminary optimization of processing and formulation parameters was done by the design of an experimental approach. The drug-polymer ratio, stirrer speed, and crosslinking time were fixed as independent variables, to analyze the effect on the entrapment efficiency (% EE) and in vitro drug release of the drug. The formulation (D8) obtained from 2³ full factorial designs was further coated using Eudragit EPO to extend the release pattern of the entrapped drug. Furthermore, the 1:1 ratio of core to polymer depicted spherical particle size of ~175 nm, % EE of 64.83%, 97.59% cumulative drug release, and higher flux (40.39 ± 3.52 µg.h/cm²). Finally, the intranasal ciliotoxicity study on sheep nasal mucosa revealed that the exposure of developed nanoparticles was similar to the negative control group, while destruction of normal architecture was noticed in the positive control test group. Overall, from the in vitro results it could be summarized that the optimization of nanoparticles' formulation of rivastigmine for intranasal application would be retained at the application site for a prolonged duration to release the entrapped drug without producing any local toxicity at the mucosal region.

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).

Lamotrigine loaded PLGA nanoparticles intended for direct nose to brain delivery in epilepsy: pharmacokinetic, pharmacodynamic and scintigraphy study

The present study aimed to investigate the brain targeting efficacy of Lamotrigine (LTG) loaded PLGA nanoparticles (LTG-PNPs) upon intranasal administration. LTG-PNPs were fabricated through the emulsification-solvent evaporation technique and evaluated for % Entrapment efficiency, particle size, in-vitro release, surface morphology, crystallinity, ex-vivo permeation & thermal behaviour. Biodistribution, gamma scintigraphy, and pharmacodynamic studies were performed in BALB/c mice, New Zealand rabbits, and Wistar rats respectively. LTG-PNPs exhibited % EE 71%; particle size 170.0 nm; Polydispersity index 0.191; zeta potential -16.60 mV. LTG-PNPs exhibited a biphasic release pattern. Biodistribution and gamma scintigraphy studies proved a greater amount of LTG in the brain following intranasal delivery of LTG-PNPs in comparison to LTG-SOL. Pharmacodynamic studies demonstrated delayed seizure onset time with LTG-PNPs in comparison to LTG-SOL. Intranasal administration of LTG-PNPs provided prolonged release, higher bioavailability, and better brain targeting bypassing the BBB. The developed formulation could be administered as a once-a-day formulation that would reduce the dosing frequency; dose; dose-related side effects; cost of the therapy and would be beneficial in the management of epilepsy as compared to the LTG-SOL. However, the proof of concept generated through these studies needs to be further validated in higher animals and human volunteers.

Physiological and Pathological Factors Affecting Drug Delivery to the Brain by Nanoparticles

The prevalence of neurological/neurodegenerative diseases, such as Alzheimer's disease is known to be increasing due to an aging population and is anticipated to further grow in the decades ahead. The treatment of brain diseases is challenging partly due to the inaccessibility of therapeutic agents to the brain. An increasingly important observation is that the physiology of the brain alters during many brain diseases, and aging adds even more to the complexity of the disease. There is a notion that the permeability of the blood-brain barrier (BBB) increases with aging or disease, however, the body has a defense mechanism that still retains the separation of the brain from harmful chemicals in the blood. This makes drug delivery to the diseased brain, even more challenging and complex task. Here, the physiological changes to the diseased brain and aged brain are covered in the context of drug delivery to the brain using nanoparticles. Also, recent and novel approaches are discussed for the delivery of therapeutic agents to the diseased brain using nanoparticle based or magnetic resonance imaging guided systems. Furthermore, the complement activation, toxicity, and immunogenicity of brain targeting nanoparticles as well as novel in vitro BBB models are discussed.

A comparison study of lipid and polymeric nanoparticles in the nasal delivery of meloxicam: Formulation, characterization, and in vitro evaluation

With the increasingly widespread of central nervous system (CNS) disorders and the lack of sufficiently effective medication, meloxicam (MEL) has been reported as a possible medication for Alzheimer's disease (AD) management. Unfortunately, following the conventional application routes, the low brain bioavailability of MEL forms a significant limitation. The intranasal (IN) administration route is considered revolutionary for CNS medications delivery. The objective of the present study was to develop two types of nanocarriers, poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) and solid lipid nanoparticles (SLNs), for the IN delivery of MEL adapting the Quality by Design approach (QbD). Turning then to further enhance the optimized nanoformulation behavior by chitosan-coating. SLNs showed higher encapsulation efficacy (EE) and drug loading (DL) than PLGA NPs 87.26% (EE) and 2.67% (DL); 72.23% (EE) and 2.55% (DL), respectively. MEL encapsulated into the nanoformulations improved in vitro release, mucoadhesion, and permeation behavior compared to the native drug with greater superiority of chitosan-coated SLNs (C-SLNs). In vitro-in vivo correlation (IVIVC) results estimated a significant in vivo brain distribution of the nanoformulations compared to native MEL with estimated greater potential in the C-SLNs. Hence, MEL encapsulation into C-SLNs towards IN route can be promising in enhancing its brain bioavailability.

Nose to brain delivery of tailored clozapine nanosuspension stabilized using (+)-alpha-tocopherol polyethylene glycol 1000 succinate: Optimization and in vivo pharmacokinetic studies

Clozapine is widely used to treat schizophrenia as an atypical antipsychotic. Low solubility, poor dissolution rate, degradation in the gastrointestinal tract, high hepatic first-pass metabolism, and eventually less drug transfer in the brain are all issues with oral clozapine administration. On account of this poor pharmacokinetic parameters, the authors aimed to develop clozapine nanosuspension using (+)-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS) and polyvinylpyrrolidone K-30 (PVP K-30) and deliver it through the intranasal route. The nanosuspension was prepared by the high-speed homogenization method with 3² full factorial design for optimization of the product. Quality Target Product Profile (QTPP) was enlisted before the product development. The amount of TPGS and speed of homogenizer were selected as independent variables whereas, particle size and drug permeation profile after 24 h (Y₂, %) were selected as dependent variables. As per the results of optimization, amount of TPGS and speed of homogenizer were chosen as 0.1% and 7000 rpm, respectively. The particle size of the optimized nanosuspension of clozapine was found to be 281 nm. The conversion of clozapine crystals to an amorphous form was verified by characterization studies (XRD and DSC). The drug permeability study showed 96.15% and 41.12% clozapine release after 24 h from nanosuspension and conventional suspension, respectively. The study of nasal cilio-toxicity (histopathological studies) demonstrated the appropriateness of nanosuspension for intranasal purposes. The single-dose in vivo pharmacokinetic analysis in the rat model showed a substantial increase in the therapeutic concentration of clozapine in the brain tissue in the case of intranasal nanosuspension (dose = 0.05 mg drug/0.1 mL, C_max = 8.62 ± 0.45 μg/g, t_max = 1 h) compared to conventional oral clozapine suspension (dose = 26.43 mg drug/0.158 mL, C_max = 1.14 ± 0.12 μg/g, t_max = 1 h).Ultimately, in the case of an intranasal route, a 3.56-fold increase in brain drug concentration was observed with a 528-fold lower drug dose compared with oral administration. The results suggest that clozapine nanosuspension may be used for successful nose-to-brain delivery.

β-Caryophyllene nanoparticles design and development: Controlled drug delivery of cannabinoid CB2 agonist as a strategic tool towards neurodegeneration

The sesquiterpene β-caryophyllene (BCP) is a structurally singular cannabinoid and a selective agonist of the CB2 receptor, which in addition to being expressed in the CNS, is intrinsically expressed within the immune system and lacks psychoactivity. Nanoencapsulation of BCP can allow its controlled release into the CNS and intranasal administration. Thus, a protocol for nanoencapsulation of BCP was developed and optimized in order to adjust the desired bioactive content and physicochemical parameters. The formulation was assessed regarding nanoparticle size, zeta potential, morphology, pH, osmolarity, stability, and drug release kinetics in vitro. The final composition of the BCP nanoparticles presented in its organic phase (OP) Tween 20 (0.25%), BCP (0.1%), and PEG 400 (5%); and in its aqueous phase (AP) ultrapure water and poloxamer P188 (0.25%). The formulation showed to be suitable for intranasal administration, presenting pH 6.5 and osmolarity of 150 mmol/kg. The mean particle diameter was 147.2 nm, PDI 0.052, and zeta potential of -24.5. The accelerated stability test showed that nanoparticles were stable for up to 1 month, when reversible creaming effect occurred. Besides, it was noted a low rate of particle accumulation and particle size distribution remained unchanged. BCP nanoparticles were shown to be promptly released in physiological medium (up to 60 min). In this work, a formulation containing β-caryophyllene nanoparticles suitable for physiological administration and preclinical tests was successfully developed.

A Short Review on the Intranasal Delivery of Diazepam for Treating Acute Repetitive Seizures

Benzodiazepines such as diazepam, lorazepam and midazolam remained the mainstay of treatment for acute repetitive seizures (ARS). The immediate care for ARS should often begin at home by a caregiver. This prevents the progression of ARS to prolonged seizures or status epilepticus. For a long time and despite social objections rectal diazepam gel remained only FDA-approved rescue medication. Intranasal administration of benzodiazepines is considered attractive and safe compared with rectal, buccal and sublingual routes. Intranasal delivery offers numerous advantages such as large absorptive surface area, bypass the first-pass metabolism and good patient acceptance as it is needle free and painless. Recent clinical studies have demonstrated that diazepam nasal spray (NRL-1; Valtoco^®, Neurelis Inc.,San Diego, CA, USA) showed less pharmacokinetic variability and reliable bioavailability compared with the diazepam rectal gel. Diazepam nasal spray could be considered as a suitable alternative for treating seizure emergencies outside the hospital. This review summarizes the treatment options for ARS and findings from clinical studies involving intranasal diazepam for treating seizure emergencies.

Nose-to-Brain Delivery of Diazepam from an Intranasal Aqua-Triggered In-Situ (ATIS) Gelling Microemulsion: Monitoring Brain Uptake by Microdialysis

BACKGROUND AND OBJECTIVES

An innovative intranasal aqua-triggered in-situ (ATIS) gel is a polymer-free in-situ gelling microemulsion which gels instantaneously on contact with minute quantities of water to form a mucoadhesive gel. The objective of the study was to develop ATIS diazepam (ATIS-diazepam) as an alternative to the injection for epileptic emergencies and evaluate its brain uptake and nose-to-brain targeting efficiency in rats.

METHODS

ATIS-diazepam (1 mg/100 µL) was prepared and characterized for in vitro formulation characteristics. An LC-MS/MS method was developed and validated for the bioanalysis of diazepam. In vivo studies for pharmacokinetics, brain uptake and nasal irritation of intranasal ATIS-diazepam were conducted in rats. Brain uptake was investigated with brain microdialysis, a highly sensitive technique enabling quantification of free drug, which correlates to efficacy.

RESULTS

ATIS-diazepam exhibited globule size < 200 nm, low viscosity, negative zeta potential and good stability. A significant increase in mucoadhesion was exhibited by ATIS-diazepam following the addition of a small quantity of water. ATIS-diazepam showed burst release in pH 6.4 with 50% diazepam release in ~ 10 min, which was sustained over 1 h. The absolute bioavailability was ~ 50% with both intranasal free-diazepam and ATIS-diazepam. Intranasal administration of ATIS-diazepam revealed immediate absorption with rapid and high brain extracellular fluid concentration compared to intravenous free-diazepam solution. The estimated direct transport potential and drug targeting efficiency of intranasal ATIS-diazepam was significantly higher (2-fold) than intranasal free-diazepam solution, which was attributed to the mucoadhesive and microemulsion properties of ATIS-diazepam. The nasal irritation study revealed the safety of ATIS-diazepam compared to free-diazepam solution.

CONCLUSION

Intranasal ATIS-diazepam showed promise of higher direct nose-to-brain targeting, better safety and hence has an immense implication in the treatment of epileptic emergencies.

Current Nanoparticle Approaches in Nose to Brain Drug Delivery and Anticancer Therapy - A Review

Nanoparticles (NPs) are unique may be organic or inorganic, play a vital role in the development of drug delivery targeting the central nervous system (CNS). Intranasal drug delivery has shown to be an efficient strategy with attractive application for drug delivery to the CNS related diseases, such as Parkinson's disease, Alzheimer 's disease and brain solid tumors. Blood brain barrier (BBB) and blood-cerebrospinal fluid barriers are natural protective hindrances for entry of drug molecules into the CNS. Nanoparticles exhibit excellent intruding capacity for therapeutic agents and overcome protective barriers. By using nanotechnology based NPs targeted, drug delivery can be improved across BBB with discharge drugs in a controlled manner. NPs confer safe from degradation phenomenon. Several kinds of NPs are used for nose to the brain (N2B) enroute, such as lipidemic nanoparticles, polymeric nanoparticles, inorganic NPs, solid lipid NPs, dendrimers. Among them, popular lipidemic and polymeric NPs are discussed, and their participation in anti-cancer activity has also been highlighted in this review.

Chitosan-coated PLGA nanoparticles for the nasal delivery of ropinirole hydrochloride: In vitro and ex vivo evaluation of efficacy and safety

Nose-to-brain delivery is an attractive route for direct drug delivery to the central nervous system (CNS), avoiding hepatic first-pass metabolism and solving blood-brain barrier passage issues. Therefore, the aim of the present study was the development of PLGA and PLGA/chitosan (chit) nanoparticles (NPs) with mucoadhesive properties, able to encapsulate ropinirole hydrochloride (RH), an anti-Parkinsonian dopaminergic agonist, and suitable to promote RH delivery across the nasal mucosa. NPs produced by nanoprecipitation showed spherical shape and a mean average size of 98.8 nm and 468.0 nm (PLGA and PLGA/chit, respectively). RH loaded PLGA/chit NPs showed a complete release of the drug in simulated nasal electrolyte solution (SNES) over the period of 24 h and increased the permeation of RH through sheep nasal mucosa by 3.22-fold in comparison to PLGA NPs. None of RH loaded NPs induced hemolysis in whole blood or the production of reactive oxygen species (ROS) in Raw 264.7 cells. On their turn, PLGA/chit NPs decreased cell viability of Raw 264.7 cells and Peripheral Blood Mononuclear Cells (PBMCs) in a concentration-dependent manner. These results revealed that, particularly PLGA/chit NPs, could be a valuable carrier for the delivery of RH to the CNS, opening a new path for Parkinson's disease therapy.

PLGA nanoparticles for nose to brain delivery of Clonazepam: formulation, optimization by 32 Factorial design, in vitro and in vivo evaluation

BACKGROUND

Intranasal administration of biodegradable nanoparticles has been extensively studied for targeting the drug directly to CNS through olfactory or trigeminal route bypassing blood brain barrier.

OBJECTIVE

The objective of the present study was to optimize Clonazepam loaded PLGA nanoparticles (CLO-PNPs) by investigating the effect of process variables on the responses using 32 full factorial design.

METHODS

Effect of two independent factors-amount of PLGA and concentration of Poloxamer 188, were studied at low, medium and high levels on three dependent responses-%Entrapment efficiency, Particle size (nm) and %cumulative drug release at 24hr.

RESULTS

%EE, Particle size and %CDR at 24hr of optimized batch was 63.7%, 165.1 nm and 86.96% respectively. Nanoparticles were radiolabeled with 99mTc and biodistribution was investigated in BALB/c mice after intranasal & intravenous administrations. Significantly higher brain/blood uptake ratios and AUC values in brain following intranasal administration of CLO-PNPs indicated more effective brain targeting of CLO. Higher brain uptake of intranasal CLO-PNPs was confirmed by rabbit brain scintigraphy imaging. Histopathological study performed on goat nasal mucosa revealed no adverse response of nanoparticles. TEM image exhibited spherical shaped particles in nano range. DSC and XRD studies suggested Clonazepam encapsulation within PLGA matrix. The onset of occurrence of PTZ-induced seizures in rats was significantly delayed by intranasal nanoparticles as compared to intranasal & intravenous CLO-SOL.

CONCLUSION

This investigation exhibits rapid rate and higher extent of CLO transport in brain with intranasal CLO-PNPs suggesting a better option as compared to oral & parenteral route in management of acute status epilepticus.

Enhanced nose-to-brain delivery of tranilast using liquid crystal formulations

Intranasal administration is poised as a competent method in delivering drugs to the brain, because the nasal route has a direct link with the central nervous system bypassing the formidable blood-brain barrier. C₁₇-monoglycerol ester (MGE) and glyceryl monooleate (GMO) as liquid crystal (LC)-forming lipids possess desirable formulation characteristics as drug carriers for intranasally administered drugs. This study investigated the effect of LC formulations on the pharmacokinetics of tranilast (TL), a lipophilic model drug, and its distribution in the therapeutic target regions of the brain in rats. The anatomical biodistribution of LC formulations was monitored using micro-computed tomography tandem in vivo imaging systems. MGE and GMO effectively formed LC with suitable particle size, zeta potential, and viscosity supporting the delivery of TL to the brain. MGE and GMO LC formulations enhanced brain uptake by 10- to 12-fold and 2- to 2.4- fold, respectively, compared with TL solution. The olfactory bulb had the highest TL concentration and fluorescent signals among all the brain regions, indicating a direct nose-to-brain delivery pathway of LC formulations. LC-forming lipids, MGE and GMO, are potential biomaterials in formulations intended for intranasal administration.

Nanomedicine: a new paradigm to overcome drug incompatibilities

OBJECTIVES

Drug incompatibilities may compromise the safety and effectiveness of combined drugs and result in mild-to-serious clinical complications, such as catheter obstruction, loss of drug efficacy, formation of toxic derivatives and embolism. Various preventive strategies have been implemented to overcome drug incompatibilities with limited success. This review presents an innovative approach to prevent drug incompatibilities via isolating the incompatible drugs into nanostructures.

KEY FINDINGS

Several examples of incompatible drugs may be loaded separately into nanostructures of various types. Physicochemical characteristics and biocompatibility of the nanomaterials that are being utilized to prevent physicochemical incompatibilities should be carefully considered.

CONCLUSIONS

There is a new era of exploiting nanomaterials in overcoming various types of physicochemical incompatibilities, with additional benefits of further improvements in pharmacokinetic profiles and pharmacological actions of the administered drugs.

Omar M, A. Mahmoud H, A. Abou-Taleb H. Nanostructured Lipid Carriers to Mediate Brain Delivery of Temazepam: Design and In Vivo Study

The opposing effect of the blood–brain barrier against the delivery of most drugs warrants the need for an efficient brain targeted drug delivery system for the successful management of neurological disorders. Temazepam-loaded nanostructured lipid carriers (NLCs) have shown possibilities for enhancing bioavailability and brain targeting affinity after oral administration. This study aimed to investigate these properties for insomnia treatment. Temazepam-NLCs were prepared by the solvent injection method and optimized using a 4² full factorial design. The optimum formulation (NLC-1) consisted of; Compritol^® 888 ATO (75 mg), oleic acid (25 mg), and Poloxamer^® 407 (0.3 g), with an entrapment efficiency of 75.2 ± 0.1%. The average size, zeta potential, and polydispersity index were determined to be 306.6 ± 49.6 nm, −10.2 ± 0.3 mV, and 0.09 ± 0.10, respectively. Moreover, an in vitro release study showed that the optimized temazepam NLC-1 formulation had a sustained release profile. Scintigraphy images showed evident improvement in brain uptake for the oral ^99mTc-temazepam NLC-1 formulation versus the ^99mTc-temazepam suspension. Pharmacokinetic data revealed a significant increase in the relative bioavailability of ^99mTc-temazepam NLC-1 formulation (292.7%), compared to that of oral ^99mTc-temazepam suspension. Besides, the NLC formulation exhibited a distinct targeting affinity to rat brain. In conclusion, our results indicate that the developed temazepam NLC formulation can be considered as a potential nanocarrier for brain-mediated drug delivery in the out-patient management of insomnia.

Memantine nanoemulsion: a new approach to treat Alzheimer's disease

Aim: A nanoemulsion loaded with memantine for intranasal delivery to bypass the blood-brain barrier for the treatment of Alzheimer disease.Method: The nanoemulsion was prepared using homogenisation and ultrasonication methods. The developed nanoemulsion was characterised, in vitro release and antioxidant potential was analysed. The in vivo studies were carried out by radiolabelling the memantine with technetium pertechnetate.Results: The finalised NE showed particle-size of ∼11 nm and percentage transmittance of ∼99%. The in vitro release studies showed 80% drug release in simulated nasal fluid. The nanoemulsion showed 98% cell viability and antioxidative assays confirmed that the encapsulation of memantine in a nanoemulsion sustained its antioxidative potential. Gamma images and biodistribution results also confirmed higher uptake of formulation with %radioactivity of 3.6 ± 0.18%/g at 1.5 h in brains of rats administered intranasally.Conclusion: The developed nanoemulsion could be used as a potential carrier of memantine for a direct nose to brain delivery.

Development and ex-vivo skin permeation studies of finasteride–poly(lactic acid-co-glycolic acid) and minoxidil–chitosan nanoparticulate systems

This study was designed to improve the permeability of two drugs (finasteride and minoxidil) through the skin. Finasteride-loaded poly(lactic acid- co-glycolic acid) and minoxidil-loaded chitosan nanoparticles were prepared by nanoprecipitation and ionic gelation method, respectively, and subsequently incorporated into semisolid Carbopol 940 gel. These fabricated nanoparticles were characterized for their pharmaceutical and chemical behavior. Nanoparticles were found a nearly spherical shape in the scanning electron microscopic studies and exhibited particle size in a range of 211–1012 nm. Finasteride- and minoxidil-loaded nanoparticles were optimized for relatively higher entrapment efficiency of 98% and 95%, respectively, by using the optimal concentration of polymers and stabilizers. All formulations were clear with smooth homogeneous texture and having pH values compatible with that of skin. This nanoparticulate system suspended in gel prolonged the release of drugs for up to 24 h and enhanced the drug permeability through the skin and retention of drug-loaded nanoparticles within the hair follicular routes. Therefore, these nanoparticles incorporated in the gel were found as a promising candidate for topical application in the treatment of alopecia by reducing the dosing frequency and adverse effects and as an effective strategy for improving the patient compliance toward therapy.

Nose-to-Brain Delivery of Cancer-Targeting Paclitaxel-Loaded Nanoparticles Potentiates Antitumor Effects in Malignant Glioblastoma

Glioblastoma multiforme (GBM) is an aggressive tumor with no curative treatment. The tumor recurrence after resection often requires chemotherapy or radiation to delay the infiltration of tumor remnants. Intracerebral chemotherapies are preferentially being used to prevent tumor regrowth, but treatments remain unsuccessful because of the poor drug distribution in the brain. In this study, we investigated the therapeutic efficacy of cancer-targeting arginyl-glycyl-aspartic tripeptide (RGD) conjugated paclitaxel (PTX)-loaded nanoparticles (NPs) against GBM by nose-to-brain delivery. Our results demonstrated that RGD-modified PTX-loaded NPs showed cancer-specific delivery and enhanced anticancer effects in vivo. The intranasal (IN) inoculation of RGD-PTX-loaded NPs effectively controls the tumor burden (75 ± 12% reduction) by inducing apoptosis and/or inhibiting cancer cell proliferation without affecting the G₀ stage of normal brain cells. Our data provide therapeutic evidence supporting the use of intranasally delivered cancer-targeted PTX-loaded NPs for GBM therapy.

Nose-to-brain delivery of lamotrigine-loaded PLGA nanoparticles

Direct nose-to-brain delivery of drugs and faster onset of action have made intra-nasal route a much sought-after alternative to conventional routes of drug delivery to the brain. Lamotrigine is used for the treatment and management of neuropathic pain, and in the present work, lamotrigine (LTG)-PLGA nanoparticles were developed for intra-nasal delivery. The LTG-PLGA nanoparticles were prepared using modified nanoprecipitation method via high-speed homogenization and ultra-sonication techniques. Entrapment efficiency (EE%) of developed LTG-PLGA-NPs was found to be 84.87 ± 1.2% with drug loading of 10.21 ± 0.89%. The particle size of developed nanoparticles was found to be 184.6 nm with PDI value of 0.082 and zeta potential of - 18.8 mV. Dissolution profiles were studied in PBS (pH 7.4), simulated nasal fluid, and simulated cerebrospinal fluid where almost complete release was observed within 5 h in CSF. In vitro, cytotoxicity was analyzed using MTT assay where dose-dependent cytotoxicity was observed for developed LTG-PLGA-NPs. In vitro cytokine analysis showed positive effects of LTG-PLGA-NPs as pro-inflammatory cytokine suppressors. Further, in vivo studies were performed for radiolabeled formulation and drug (^99mTc-LTG-PLGA-NPs and ^99mTc-LTG-aqueous) using Sprague Dawley rats where with the help of gamma scintigraphy studies, various routes of administration viz. oral, intra-nasal, and intra-venous were compared. Various pharmacokinetic parameters were evaluated using biodistribution studies to estimate the drug levels in blood and brain. For ^99mTc-LTG-PLGA-NPs via intra-nasal route, drug targeting efficiency (DTE%) was found to be 129.81% and drug target organ transport (DTP%) to be 22.81% in brain with C_max of 3.82%/g within T_max 1.5 h. Thus, the developed PLGA nanoparticles for intra-nasal delivery provide a possible alternative for existing available drug formulation for neuropathic pain management.

Targeting Small Molecule Delivery to the Brain and Spinal Cord via Intranasal Administration of Rabies Virus Glycoprotein (RVG29)-Modified PLGA Nanoparticles

Alternative routes of administration are one approach that could be used to bypass the blood–brain barrier (BBB) for effective drug delivery to the central nervous system (CNS). Here, we focused on intranasal delivery of polymer nanoparticles. We hypothesized that surface modification of poly(lactic-co-glycolic acid) (PLGA) nanoparticles with rabies virus glycoprotein (RVG29) would increase residence time and exposure of encapsulated payload to the CNS compared to non-targeted nanoparticles. Delivery kinetics and biodistribution were analyzed by administering nanoparticles loaded with the carbocyanine dye 1,1′-Dioctadecyl-3,3,3′,3′-Tetramethylindotricarbocyanine Iodide (DiR) to healthy mice. Intranasal administration yielded minimal exposure of nanoparticle payload to most peripheral organs and rapid, effective delivery to whole brain. Regional analysis of payload delivery within the CNS revealed higher delivery to tissues closest to the trigeminal nerve, including the olfactory bulb, striatum, midbrain, brainstem, and cervical spinal cord. RVG29 surface modifications presented modest targeting benefits to the striatum, midbrain, and brainstem 2 h after administration, although targeting was not observed 30 min or 6 h after administration. Payload delivery to the trigeminal nerve was 3.5× higher for targeted nanoparticles compared to control nanoparticles 2 h after nanoparticle administration. These data support a nose-to-brain mechanism of drug delivery that closely implicates the trigeminal nerve for payload delivery from nanoparticles via transport of intact nanoparticles and eventual diffusion of payload. Olfactory and CSF routes are also observed to play a role. These data advance the utility of targeted nanoparticles for nose-to-brain drug delivery of lipophilic payloads and provide mechanistic insight to engineer effective delivery vectors to treat disease in the CNS.

Formulation of polymeric nanoparticles of antidepressant drug for intranasal delivery

Aim: The manuscript describes the performance of nanoparticles loaded with antidepressant drug for nose-to-brain drug delivery. Materials & methods: Poly-lactic-co-glycolic acid-loaded nanoparticles of agomelatine were prepared by nanoprecipitation method using poloxamer 407 as stabilizer. The process parameters were optimized using factorial design. Results: The drug-loaded nanoparticles having low particle size (<200 nm) with narrow size distribution and required zeta potential (-22.7 mV) to avoid aggregation showed sustained release profile and were found to have higher permeability as observed from ex vivo studies when compared with plain drug suspension. Histopathology test showed that the optimized formulation was free from nasal toxicity on the goat nasal mucosa. Pharmacodynamic study showed significant reduction in immobility time in rats treated with the formulation which indicated antidepressant activity of the formulation. Conclusion: The prepared agomelatin-loaded poly-lactic-co-glycolic acid nanoparticles showed prominent antidepressant activity by nose-to-brain delivery as observed from various studies.

Oral pentamidine-loaded poly(d,l-lactic-co-glycolic) acid nanoparticles: an alternative approach for leishmaniasis treatment

Leishmaniasis is a group of diseases caused by a protozoa parasite from one of over 20 Leishmania species. Depending on the tissues infected, these diseases are classified as cutaneous, mucocutaneous and visceral leishmaniasis. For the treatment of leishmaniasis refractory to antimony-based drugs, pentamidine (PTM) is a molecule of great interest. However, PTM displays poor bioavailability through oral routes due to its two strongly basic amidine moieties, which restricts its administration by a parenteral route and limits its clinical use. Among various approaches, nanotechnology-based drug delivery systems (nano-DDS) have potential to overcome the challenges associated with PTM oral administration. Here, we present the development of PTM-loaded PLGA nanoparticles (NPs) with a focus on the characterization of their physicochemical properties and potential application as an oral treatment of leishmaniasis. NPs were prepared by a double emulsion methodology. The physicochemical properties were characterized through the mean particle size, polydispersity index (PdI), zeta potential, entrapment efficiency, yield process, drug loading, morphology, in vitro drug release and in vivo pharmacological activity. The PTM-loaded PLGA NPs presented with a size of 263 ± 5 nm (PdI = 0.17 ± 0.02), an almost neutral charge (-3.2 ± 0.8 mV) and an efficiency for PTM entrapment of 91.5%. The release profile, based on PTM dissolution, could be best described by a zero-order model, followed by a drug diffusion profile that fit to the Higuchi model. In addition, in vivo assay showed the efficacy of orally given PTM-loaded PLGA NPs (0.4 mg kg^-1) in infected BALB/c mice, with significant reduction of organ weight and parasite load in spleen (p-value < 0.05). This work successfully reported the oral use of PTM-loaded NPs, with a high potential for the treatment of visceral leishmaniasis, opening a new perspective to utilization of this drug in clinical practice.

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.

Epilepsy Disease and Nose-to-Brain Delivery of Polymeric Nanoparticles: An Overview

Epilepsy is the fourth most common global neurological problem, which can be considered a spectrum disorder because of its various causes, seizure types, its ability to vary in severity and the impact from person to person, as well as its range of co-existing conditions. The approaches to drug therapy of epilepsy are directed at the control of symptoms by chronic administration of antiepileptic drugs (AEDs). These AEDs are administered orally or intravenously but alternative routes of administration are needed to overcome some important limits. Intranasal (IN) administration represents an attractive route because it is possible to reach the brain bypassing the blood brain barrier while the drug avoids first-pass metabolism. It is possible to obtain an increase in patient compliance for the easy and non-invasive route of administration. This route, however, has some drawbacks such as mucociliary clearance and the small volume that can be administered, in fact, only drugs that are efficacious at low doses can be considered. The drug also needs excellent aqueous solubility or must be able to be formulated using solubilizing agents. The use of nanomedicine formulations able to encapsulate active molecules represents a good strategy to overcome several limitations of this route and of conventional drugs. The aim of this review is to discuss the innovative application of nanomedicine for epilepsy treatment using nose-to-brain delivery with particular attention focused on polymeric nanoparticles to load drugs.