Intranasal delivery of antipsychotic drugs

Clozapine-laden carbon dots delivered to the brain via an intranasal pathway: Synthesis, characterization, ex vivo, and in vivo studies

Clozapine, which is widely used to treat schizophrenia, shows low bioavailability due to poor solubility and high first-pass metabolism. The study aimed to design clozapine-loaded carbon dots (CDs) to enhance availability of the clozapine to the brain via intranasal pathway. The CDs were synthesized by pyrolysis of citric acid and urea at 200 °C by hydrothermal technique and characterized by photoluminescence, transmission electron microscopy (TEM), X-ray Photoelectron Spectrometer (XPS), and Fourier transform infrared spectrum (FTIR). The optimized clozapine-loaded CDs (CLZ-CDs-1:3-200) showed a quasi-spherical shape (9-12 nm) with stable blue fluorescence. The CDs showed high drug solubilization capacity (1.5 mg drug in 1 mg/ml CDs) with strong electrostatic interaction with clozapine (drug loading efficiency = 94.74%). The ex vivo release study performed using nasal goat mucosa showed sustained release of clozapine (43.89%) from CLZ-CDs-1:3-200 for 30 h. The ciliotoxicity study (histopathology) confirmed no toxicity to the nasal mucosal tissues using CDs. In the rat model (in vivo pharmacokinetic study), when CDs were administrated by the intranasal route, a significantly higher concentration of clozapine in the brain tissue (Cmax = 58.07 ± 5.36 μg/g and AUCt (µg/h*g) = 105.76 ± 12.31) was noted within a short time (tmax = 1 h) compared to clozapine suspension administered by intravenous route (Cmax = 20.99 ± 3.91 μg/g, AUC t (µg/h*g) = 56.89 ± 12.31, and tmax = 4 h). The high value of drug targeting efficiency (DTE, 486%) index and direct transport percentage (DTP, 58%) indicates the direct entry of clozapine-CDs in the brain via the olfactory route. In conclusion, designed CDs demonstrated a promising dosage form for targeted nose-to-brain delivery of clozapine for the effective treatment of schizophrenia.

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.

Current approaches to facilitate improved drug delivery to the central nervous system

Although many pharmaceuticals have therapeutic potentials for central nervous system (CNS) diseases, few of these agents have been effectively administered. It is due to the fact that the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSF) restrict them from crossing the brain to exert biological activity. This article reviews the current approaches aiming to improve penetration across these barriers for effective drug delivery to the CNS. These issues are summarized into direct systemic delivery and invasive delivery, including the BBB disruption and convection enhanced delivery. Furthermore, novel drug delivery systems used at the nanoscale, including polymeric nanoparticles, liposomes, nanoemulsions, dendrimers, and micelles are discussed. These nanocarriers could contribute to a breakthrough in the treatment of many different CNS diseases. However, further broadened studies are needed to assess the biocompatibility and safety of these medical devices.

Development of intranasal implantable devices for schizophrenia treatment

In this work the preparation and characterisation of intranasal implants for the delivery of risperidone (RIS) is described. The aim of this work is to develop better therapies to treat chronic conditions affecting the brain such as schizophrenia. This type of systems combines the advantages of intranasal drug delivery with sustained drug release. The resulting implants were prepared using biodegradable materials, including poly(caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA). These polymers were combined with water-soluble compounds, such as poly(ethylene glycol) (PEG) 600, PEG 3000, and Tween® 80 using a solvent-casting method. The resulting implants contained RIS loadings ranging between 25 and 50%. The obtained implants were characterised using a range of techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). Moreover, in vitro RIS release was evaluated showing that the addition of water-soluble compounds exhibited significant faster release profiles compared to pristine PCL and PLGA-based implants. Interestingly, PCL-based implants containing 25% of RIS and PLGA-based implants loaded with 50% of RIS showed sustained drug release profiles up to 90 days. The former showed faster release rates over the first 28 days but after this period PLGA implants presented higher release rates. The permeability of RIS released from the implants through a model membrane simulating nasal mucosa was subsequently evaluated showing desirable permeation rate of around 2 mg/day. Finally, following in vitro biocompatibility studies, PCL and PLGA-based implants showed acceptable biocompatibility. These results suggested that the resulting implants displayed potential of providing prolonged drug release for brain-targeting drugs.

Advances and Challenges in Intranasal Delivery of Antipsychotic Agents Targeting the Central Nervous System

Treatment of central nervous system (CNS) disorders is challenging using conventional delivery strategies and routes of administration because of the presence of the blood–brain barrier (BBB). This BBB restricts the permeation of most of the therapeutics targeting the brain because of its impervious characteristics. Thus, the challenges of delivering the therapeutic agents across the BBB to the brain overcoming the issue of insufficient entry of neurotherapeutics require immediate attention for recovering from the issues by the use of modern platforms of drug delivery and novel routes of administration. Therefore, the advancement of drug delivery tools and delivering these tools using the intranasal route of drug administration have shown the potential of circumventing the BBB, thereby delivering the therapeutics to the brain at a significant concentration with minimal exposure to systemic circulation. These novel strategies could lead to improved efficacy of antipsychotic agents using several advanced drug delivery tools while delivered via the intranasal route. This review emphasized the present challenges of delivering the neurotherapeutics to the brain using conventional routes of administration and overcoming the issues by exploring the intranasal route of drug administration to deliver the therapeutics circumventing the biological barrier of the brain. An overview of different problems with corresponding solutions in administering therapeutics via the intranasal route with special emphasis on advanced drug delivery systems targeting to deliver CNS therapeutics has been focused. Furthermore, preclinical and clinical advancements on the delivery of antipsychotics using this intranasal route have also been emphasized.

Strategies to Improve Drug Strength in Nasal Preparations for Brain Delivery of Low Aqueous Solubility Drugs

Intranasal administration is a promising route for brain drug delivery. However, it can be difficult to formulate drugs that have low water solubility into high strength intranasal solutions. Hence, the purpose of this work was to review the strategies that have been used to increase drug strength in intranasal liquid formulations. Three main groups of strategies are: the use of solubilizers (change in pH, complexation and the use cosolvents/surfactants); incorporation of the drugs into a carrier nanosystem; modifications of the molecules themselves (use of salts or hydrophilic prodrugs). The use of high amounts of cosolvents and/or surfactants and pH decrease below 4 usually lead to local adverse effects, such as nasal and upper respiratory tract irritation. Cyclodextrins and (many) different carrier nanosystems, on the other hand, could be safer for intranasal administration at reasonably high concentrations, depending on selected excipients and their dose. While added attributes such as enhanced permeation, sustained delivery, or increased direct brain transport could be achieved, a great effort of optimization will be required. On the other hand, hydrophilic prodrugs, whether co-administered with a converting enzyme or not, can be used at very high concentrations, and have resulted in a fast prodrug to parent drug conversion and led to high brain drug levels. Nevertheless, the choice of which strategy to use will always depend on the characteristics of the drug and must be a case-by-case approach.

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

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

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.

Characteristics of SARS-CoV2 that may be useful for nanoparticle pulmonary drug delivery

As a non-invasive method of local and systemic drug delivery, the administration of active pharmaceutical ingredients (APIs) via the pulmonary route represents an ideal approach for the therapeutic treatment of pulmonary diseases. The pulmonary route provides a number of advantages, including the rapid absorption which results from a high level of vascularisation over a large surface area and the successful avoidance of first-pass metabolism. Aerosolization of nanoparticles (NPs) is presently under extensive investigation and exhibits a high potential for targeted delivery of therapeutic agents for the treatment of a wide range of diseases. NPs need to possess specific characteristics to facilitate their transport along the pulmonary tract and appropriately overcome the barriers presented by the pulmonary system. The most challenging aspect of delivering NP-based drugs via the pulmonary route is developing colloidal systems with the optimal physicochemical parameters for inhalation. The physiochemical properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been investigated as a template for the synthesis of NPs to assist in the formulation of virus-like particles (VLPs) for pharmaceutical delivery, vaccine production and diagnosis assays.

Current State and Future Directions of Intranasal Delivery Route for Central Nervous System Disorders: A Scientometric and Visualization Analysis

Background: The management of various central nervous system (CNS) disorders has been challenging, due to highly compact blood-brain barrier (BBB) impedes the access of most pharmacological agents to the brain. Among multiple strategies proposed to circumvent this challenge, intranasal delivery route has sparked great interest for brain targeting in the past decades. The aim of this study was to apply scientometric method to estimate the current status and future trends of the field from a holistic perspective.

Methods: All relevant publications during 1998–2020 were retrieved from the Web of Science Core Collection (SCIE, 1998-present). Two different scientometric software including VOS viewer and CiteSpace, and one online platform were used to conduct co-authorship, co-citation, and co-occurrence analysis of journals, countries, institutes, authors, references and keywords.

Results: A total of 2,928 documents, including 2,456 original articles and 472 reviews, were retrieved. Our analysis revealed a significant increasing trend in the total number of scientific publications over the past 2 decades (R² = 0.98). The United States dominated the field, reflecting in the largest amount of publications (971), the highest H-index (99), and extensive international collaboration. Jamia Hamdard contributed to most publications. Frey WH and Illum L were key researchers with the highest number of publications and citations, respectively. The International Journal of Pharmaceutics was the most influential academic journal, and Pharmacology/Pharmacy and Neurosciences/Neurology were the hottest research categories in this field. Based on keywords occurrence analysis, four main topics were identified, and the current research focus of this field has shifted from cluster 4 (pathways and mechanisms of intranasal delivery) to cluster 2 (the study of nasal drug delivery systems), especially the nanostructured and nano-sized carrier systems. Keywords burst detection revealed that the research focus on oxidative stress, drug delivery, neuroinflammation, nanostructured lipid carrier, and formulation deserves our continued attention.

Conclusion: To the authors’ knowledge, this is the first scientometric analysis regarding intranasal delivery research. This study has demonstrated a comprehensive knowledge map, development landscape and future directions of intranasal delivery research, which provides a practical and valuable reference for scholars and policymakers in this field.

RNA therapeutics for mood disorders: current evidence toward clinical trials

INTRODUCTION

Mood disorders are severe yet frequent psychiatric disorders worldwide, comprising major depressive disorder (MDD) and bipolar disorders (BD). Their treatment remains poorly effective. Recently, growing evidence for epigenetic mechanisms has emerged. Consequently, a great interest in a novel pharmacological class arose: RNA therapeutics.

AREAS COVERED

We conducted a systematic review of RNA therapeutics -antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), short hairpin RNAs (shRNAs), and micro-RNA (miRNA) therapeutics- for the treatment of mood disorders studied in pre-clinical animal models listed in PubMed, in clinical trials registered in ClinicalTrials.gov and available on the market by combining literature search and Food and Drug Administration and European Medicine Agency online databases. Eighteen pre-clinical studies investigated the antidepressant effects of RNA therapeutics. However, even though there is an increasing number of marketing authorizations and clinical trials for the past twenty years, no RNA therapeutic has reached the clinical development pipeline for the treatment of psychiatric disorders yet.

EXPERT OPINION

Several promising RNA therapeutics have been tested in pre-clinical studies for MDD, whereas no molecule has been developed for BD. There are several issues to address before reaching clinical development and new challenges include stratifying patient population and predicting therapeutic response.

Microemulsion-Based Media in Nose-to-Brain Drug Delivery

Nose-to-brain drug delivery has recently attracted enormous attention as an alternative to other delivery routes, including the most popular oral one. Due to the unique anatomical features of the nasal cavity, drugs administered intranasally can be delivered directly to the central nervous system. The most important advantage of this approach is the ability to avoid the blood-brain barrier surrounding the brain and blocking the entry of exogenous substances to the central nervous system. Moreover, selective brain targeting could possibly avoid peripheral side effects of pharmacotherapy. The challenges associated with nose-to-brain drug delivery are mostly due to the small volume of the nasal cavity and insufficient drug absorption from nasal mucosa. These issues could be minimized by using a properly designed drug carrier. Microemulsions as potential drug delivery systems offer good solubilizing properties and the ability to enhance drug permeation through biological membranes. The aim of this review is to summarize the current status of the research focused on microemulsion-based systems for nose-to-brain delivery with special attention to the most extensively investigated neurological and psychiatric conditions, such as neurodegenerative diseases, epilepsy, and schizophrenia.

Characterization and Systemic Delivery of Dibenzoylmethane via the Intranasal Route

Intranasal (IN) administration is known to be noninvasive with the potential to carry a drug or vaccine directly to the blood, bypassing first-pass metabolism in the liver and the harsh environment of the gastrointestinal system. Orally administered dibenzoylmethane (DBM) has been shown experimentally to be neuroprotective in animal models of tauopathy and prion disease and effective in the treatment of certain forms of cancers. The purpose of this study was to prepare, characterize, and test formulations of DBM designed for IN administration. DBM was formulated in brain homogenate (BH) and hypromellose and as nanoparticles (NPs). These formulations were detected using UPLC and characterized in solid and suspension states; NPs were also characterized by in vitro cell culture-based studies. Particle size for DBM NP was 163.8 ± 3.2 nm, and in vitro release studies showed 95.80% of DBM was released from the NPs within 8 days. In vitro cell, culture studies suggested no drug uptake until 6 h. A histological analysis of nasal cavity (NC) sections and blood detection studies were carried out 30 min after inhalation. DBM amounting to 40.77 ± 4.93 and 44.45 ± 5.36 ng/mL was detected in the blood of animals administered DBM in polymeric and NP formulation, respectively. Histological studies on NCs confirmed the presence of BH within lymphatic vessels in the lamina propria of each animal; BH was identified traversing the mucosa in 2 animals. Thus, formulations for DBM administered via IN route were successfully designed and characterized and able to cross the nasal mucosa following inhalation.

In situ-gelling starch nanoparticle (SNP)/O-carboxymethyl chitosan (CMCh) nanoparticle network hydrogels for the intranasal delivery of an antipsychotic peptide

Existing oral or injectable antipsychotic drug delivery strategies typically demonstrate low bioavailability to targeted brain regions, incentivizing the development of alternative delivery strategies. Delivery via the nasal cavity circumvents multiple barriers for reaching the brain but requires drug delivery vehicles with very specific properties to be effective. Herein, we report in situ-gelling and degradable bulk nanoparticle network hydrogels consisting of oxidized starch nanoparticles (SNPs) and carboxymethyl chitosan (CMCh) that enable intranasal delivery via spray, high nasal mucosal retention, and functional controlled release of the peptide drug PAOPA, a positive allosteric modulator of dopamine D2 receptor. PAOPA-loaded SNP-CMCh hydrogels can alleviate negative symptoms like behavioural abnormalities associated with schizophrenia (i.e. decreased social interaction time) for up to 72 h in an MK-801-induced pre-clinical rat model of schizophrenia at a low drug dosage (0.5 mg/kg); in comparison, conventional PAOPA administration via the intraperitoneal route requires twice the PAOPA dose to achieve a therapeutic effect that persists for only a few hours. This strategy offers potential for substantially decreasing re-administration frequencies and overall drug doses (and thus side-effects) of a range of potential antipsychotic drugs via a minimally-invasive administration route.

miR-218 in Adolescence Predicts and Mediates Vulnerability to Stress

BACKGROUND

Adolescence is a period of increased vulnerability to psychiatric disorders, including depression. Discovering novel biomarkers to identify individuals who are at high risk is very much needed. Our previous work shows that the microRNA miR-218 mediates susceptibility to stress and depression in adulthood by targeting the netrin-1 guidance cue receptor gene Dcc in the medial prefrontal cortex (mPFC).

METHODS

Here, we investigated whether miR-218 regulates Dcc expression in adolescence and could serve as an early predictor of lifetime stress vulnerability in male mice.

RESULTS

miR-218 expression in the mPFC increases from early adolescence to adulthood and correlates negatively with Dcc levels. In blood, postnatal miR-218 expression parallels changes occurring in the mPFC. Notably, circulating miR-218 levels in adolescence associate with vulnerability to social defeat stress in adulthood, with high levels associated with social avoidance severity. Indeed, downregulation of miR-218 in the mPFC in adolescence promotes resilience to stress in adulthood.

CONCLUSIONS

miR-218 expression in adolescence may serve both as a marker of risk and as a target for early interventions.

Brain Delivery of Single-Domain Antibodies: A Focus on VHH and VNAR

Passive immunotherapy, i.e., treatment with therapeutic antibodies, has been increasingly used over the last decade in several diseases such as cancers or inflammation. However, these proteins have some limitations that single-domain antibodies could potentially solve. One of the main issues of conventional antibodies is their limited brain penetration because of the blood-brain barrier (BBB). In this review, we aim at exploring the different options single-domain antibodies (sDAbs) such as variable domain of heavy-chain antibodies (VHHs) and variable new antigen receptors (VNARs) have already taken to reach the brain allowing them to be used as therapeutic, diagnosis or transporter tools.

Schizophrenia; A Review on Promising Drug Delivery Systems

Background:

Schizophrenia belongs to mental illnesses affecting 1% of the worldwide population. Its therapy is still unmet; thus, researchers aimed to develop new pharmacological molecules which can improve its management.

Methods:

Moreover, the current typical and atypical antipsychotics should be formulated in more efficacious systems that can deliver the drug in the brain with as few side effects as possible. Further, the development of long-acting efficient drug delivery systems could be significant in minimizing frequent dosing which is nonpreferred to schizophrenics.

Results:

Herein, authors focused on current developments of antipsychotic medications used in schizophrenia management. Various studies, which include the use of first and second-generation antipsychotics, were analyzed according to their efficacy. In fact, in this review, oral, injectable, transdermal and intranasal formulations entrapped antipsychotics are presented to be valuable guidance for scientists to formulate more effective drug delivery systems for schizophrenic patients.

Conclusions:

This review aimed to assist researchers working on schizophrenia management by summarizing current medications and newly synthesized drug delivery systems recently found in the literature.

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.

Active Targeting Towards and Inside the Brain based on Nanoparticles: A Review

Background:

Treatment of neurological diseases using systemic and non-surgical techniques presents a significant challenge in medicine. This challenge is chiefly associated with the condensation and coherence of the brain tissue.

Methods:

The coherence structure of the brain is due to the presence of the blood-brain barrier (BBB), which consists of a continuous layer of capillary endothelial cells. The BBB prevents most drugs from entering the brain tissue and is highly selective, permitting only metabolic substances and nutrients to pass through.

Results:

Although this challenge has caused difficulties for the treatment of neurological diseases, it has opened up a broad research area in the field of drug delivery. Through the utilization of nanoparticles (NPs), nanotechnology can provide the ideal condition for passing through the BBB.

Conclusion:

NPs with suitable dimensions and optimum hydrophobicity and charge, as well as appropriate functionalization, can accumulate in the brain. Furthermore, NPs can facilitate the targeted delivery of therapeutics into the brain areas involved in Alzheimer’s disease, Parkinson’s disease, stroke, glioma, migraine, and other neurological disorders. This review describes these methods of actively targeting specific areas of the brain.

Neuroregenerative and protective functions of Leukemia Inhibitory Factor in perinatal hypoxic-ischemic brain injury

Neonatal hypoxic-ischemic encephalopathy remains the most important neurological problem of the newborn. Delays in diagnosing perinatal brain injuries are common, preventing access to acute therapies. Therefore, there is a critical need for therapeutic strategies that are beneficial when delivered beyond 24 h after birth. Here we show that Leukemia Inhibitory Factor (LIF) functions as an essential injury-induced neurotrophic cytokine in the CNS and that non-invasively administering LIF as late as 3 days after a hypoxic-ischemic insult improves neurological function. Using a mouse model of late preterm brain injury we show that astroglial and microglial/macrophage reactivity to hypoxia-ischemia was diminished at 3 days of recovery, but then exacerbated at 2 weeks of recovery in LIF haplodeficient mice. There also were significantly more CD68+/Iba-1+ cells in the ipsilateral striatum in LIF-Het mice compared to WT mice at 2 weeks of recovery. This desynchronized glial response was accompanied by increased neuronal cell death in the striatum and neocortex (Fluorojade C), hypomyelination (reduced MBP staining and thinner external capsule), increased extent of brain damage (Nissl) and diminished neurological function on sensorimotor tests. To our surprise, injured LIF-Het mice had ~7-fold higher IGF-1 levels than injured WT mice at 3 days after HI injury. Intranasally administered LIF activated the Jak-Stat-3 pathway both within the subventricular zone and the neocortex at 30 min after administration. When delivered with a delay of 3 days after the insult, intranasal LIF reduced the extent of brain injury by ~60%, attenuated astrogliosis and microgliosis in striatum, improved subcortical white matter thickness, increased numbers of Olig2+ cells in corpus callosum and improved performance on sensorimotor tests at 2 weeks of recovery. These studies provide key pre-clinical data recommending LIF administration as a neuroprotectant and regenerative cytokine and they highlight the feasibility of pursuing new therapeutics targeting the tertiary phase of neurodegeneration for hypoxic-ischemic encephalopathies.

Pre-Clinical Assessment of the Nose-to-Brain Delivery of Zonisamide After Intranasal Administration

PURPOSE

Zonisamide clinical indications are expanding beyond the classic treatment of epileptic seizures to Parkinson's disease and other neurodegenerative diseases. However, the systemic safety profile of zonisamide may compromise its use as a first-line drug in any clinical condition. Since zonisamide is marketed as oral formulations, the present study aimed at exploring the potential of the intranasal route to centrally administer zonisamide, evaluating the systemic bioavailability of zonisamide and comparing its brain, lung and kidney pharmacokinetics after intranasal, oral and intravenous administrations.

METHODS

In vitro cell studies demonstrated that zonisamide and proposed thermoreversible gels did not affect the viability of RPMI 2650 or Calu-3 cells. Thereafter, male CD-1 mice were randomly administered with zonisamide by oral (80 mg/kg), intranasal or intravenous (16.7 mg/kg) route. At predefined time points, animals were sacrificed and plasma and tissues were collected to quantify zonisamide and describe its pharmacokinetics.

RESULTS

Intranasal route revealed a low absolute bioavailability (54.95%) but the highest value of the ratio between the area under the curve (AUC) between brain and plasma, suggesting lower systemic adverse events and non-inferior effects in central nervous system comparatively to intravenous and oral routes. Furthermore, drug targeting efficiency and direct transport percentage into the brain were 149.54% and 33.13%, respectively, corroborating that a significant fraction of zonisamide suffers direct nose-to-brain transport. Lung and kidney exposures obtained after intranasal administration were lower than those observed after intravenous injection.

CONCLUSIONS

This pre-clinical investigation demonstrates a direct nose-to-brain delivery of zonisamide, which may be a promising strategy for the treatment of central diseases.

The Gut Microbiome and Treatment-Resistance in Schizophrenia

The effect of antipsychotic medication is poor in 30-40% of patients with schizophrenia; treatment resistance is usually met with shifts to new drugs or drug augmentation strategies or a trial of clozapine. The purpose of this review was to examine the potential role of intestinal bacteria in the bioavailability of antipsychotic medication and the possibility that parenterally administered antipsychotics might be able to overcome treatment resistance. Databases were searched with appropriate terms to locate relevant papers dealing with the effect of antipsychotic drugs on the gut microbiome and the effect of bacterial metabolizing enzymes on antipsychotic drugs. Also searched were papers addressing the various current parenteral formulations of antipsychotic drugs. Sixty-five recent pertinent papers were reviewed and the results are suggestive of the premise that there is a drug refractory form of psychosis for which the composition of gut bacteria is responsible, and that parenteral drug administration could overcome the problem.

Neuropsychological Disorders and their Nanocarriers

Neuropsychological disorders are now growing rapidly worldwide among the people of diverse backgrounds irrespective of age, gender, and geographical region. Such disorders not only disturb the normal life and functionality of an individual but also impact the social relationships of the patient and the people associated with them, and if not treated in time, it may also result in mortality in severe conditions. Various antipsychotic drugs have been developed but their use is often limited by issues related to effective drug delivery at the site of action i.e. brain, mainly because of the blood-brain barrier. To resolve these issues, researchers and scientists have been working to develop a more effective drug delivery system where drugs can cross the blood-brain barrier and reach the brain in more effective concentrations. Drugs have been modified and formulated into nano-carriers and experimental studies for efficient and targeted delivery of drugs have been conducted. This review focuses on certain common neuropsychological diseases and their nanocarriers developed for drug delivery in the brain and are discussed with a brief description of various experimental in vitro and in vivo studies. This review also focuses on the intranasal route for the delivery of antipsychotic drugs and constraints faced due to the blood-brain barrier by the drugs.

Intraocular administration of tetramethylpyrazine hydrochloride to rats: a direct delivery pathway for brain targeting?

The purpose of this study was to compare the pharmacokinetic profile of tetramethylpyrazine hydrochloride (TMPH) in rat plasma and tissues following intravenous (iv), intragastric (ig) and intraocular (io) administration. After io, ig and iv administration of a single dose at 10 mg/kg, tissue and plasma samples drawn from the femoral artery were collected at timed intervals. The concentration of TMPH in the samples was analyzed using high-performance liquid chromatography (HPLC). The area under the concentration-time curve (AUC) and the drug targeting efficiency percentage (DTE(%)) were calculated to evaluate the targeting efficiency of the drug with the three different administration routes. After io administration, TMPH was rapidly absorbed to reach its peak plasma and brain concentration within 5 min. The systemic bioavailability obtained with io administration was greater than that obtained through the ig route (63.22% vs. 16.88%). The AUCt rank order of the iv administration group was AUCkidney >AUCheart >AUCliver >AUCbrain >AUCspleen >AUClung; that of the ig administration group as AUCkidney >AUCliver >AUCheart >AUCspleen >AUCbrain >AUClung; while that of the io administration group was AUCkidney >AUCbrain >AUCheart >AUCliver >AUCspleen >AUClung. The ratio of the AUCbrain value between the io route and iv injection was 1.05, which was greater than that obtained after ig administration (0.30). The DTE after io administration was calculated: brain (165.72%), heart (97.76%), liver (113.06%), spleen (105.31%), lung (163.40%) and kidney (135.31%). The io administration group showed obvious drug transport to the brain. These results indicate that TMPH is rapidly absorbed from the eye into the systemic circulation, and there may be a direct translocation pathway for TMPH from the eye to the brain. Therefore, io administration of TMPH could be a promising alternative to intravenous and oral approaches.

Nose-to-brain delivery of levetiracetam after intranasal administration to mice

Despite being one of the most commonly prescribed antiepileptic drugs, levetiracetam is marketed in oral and intravenous dosage forms, which are associated to drug-drug interactions and drug-resistant epilepsy (DRE). The purpose of the present study was to assess the potential of the intranasal route to deliver levetiracetam into the brain, due to the particular anatomical features of the nasal cavity. After development and characterization of the drug formulation, a thermoreversible gel loaded with levetiracetam was administered to CD-1 male mice by intranasal route and its pharmacokinetics compared to those observed after intravenous administration. Similar plasma pharmacokinetic profiles were obtained and the intranasal absolute bioavailability was 107.44%, underscoring that a high drug fraction was systemically absorbed. In brain tissue, maximum drug concentrations were 4.48 and 4.02 μg/g (intranasal vs intravenous) and the mean cerebral concentrations were significantly higher after intranasal administration. The percentage of drug targeting efficiency was 182.35% while direct transport percentage was 46.38%, suggesting that almost 50% of levetiracetam undergoes direct nose-to-brain delivery. Complementarily, an in vivo intranasal repeated dose toxicity study was performed and no relevant histopathological alterations were observed. The herein proposed non-invasive and safe intranasal administration route allowed a direct nose-to-brain delivery of levetiracetam and is a promising strategy for the treatment of DRE.

Formulation Strategies to Improve Nose-to-Brain Delivery of Donepezil

Donepezil (DPZ) is widely used in the treatment of Alzheimer's disease in tablet form for oral administration. The pharmacological efficacy of this drug can be enhanced by the use of intranasal administration because this route makes bypassing the blood⁻brain barrier (BBB) possible. The aim of this study was to develop a nanoemulsion (NE) as well as a nanoemulsion with a combination of bioadhesion and penetration enhancing properties (PNE) in order to facilitate the transport of DPZ from nose-to-brain. Composition of NE was established using three pseudo-ternary diagrams and PNE was developed by incorporating Pluronic F-127 to the aqueous phase. Parameters such as physical properties, stability, in vitro release profile, and ex vivo permeation were determined for both formulations. The tolerability was evaluated by in vitro and in vivo models. DPZ-NE and DPZ-PNE were transparent, monophasic, homogeneous, and physically stable with droplets of nanometric size and spherical shape. DPZ-NE showed Newtonian behavior whereas a shear thinning (pseudoplastic) behavior was observed for DPZ-PNE. The release profile of both formulations followed a hyperbolic kinetic. The permeation and prediction parameters were significantly higher for DPZ-PNE, suggesting the use of polymers to be an effective strategy to improve the bioadhesion and penetration of the drug through nasal mucosa, which consequently increase its bioavailability.

Conference proceedings of the 4th Masterclass Psychiatry: Transcultural Psychiatry - Diagnostics and Treatment, Luleå, Sweden, 22-23 February 2018 (Region Norrbotten in collaboration with the Maudsley Hospital and Tavistock Clinic London)

BACKGROUND

According to estimates from the European Commission, Europe has experienced the greatest mass movement of people since the Second World War. More than one million refugees and migrants have arrived in the European Union in the past few years. Mental health and primary care professionals are more likely than ever to meet patients from different cultures and backgrounds.

AIMS

To equip mental health and primary care professionals with transcultural skills to deal with patients from unfamiliar backgrounds.

METHOD

Lectures and case discussions to explore the latest advances in the diagnosis and treatment of serious mental health problems in a transcultural context.

RESULTS

Lectures covered transcultural aspects of mental health problems, treatment in different cultural and ethnic contexts, and assessment of risk factors for self-harm and harm in migrant populations.

CONCLUSIONS

Clinicians require a sound grounding in transcultural skills to confidently and empathically deal with patients from unfamiliar backgrounds.

Reducing the stigma of long acting injectable antipsychotics - current concepts and future developments

BACKGROUND

Long acting injectable antipsychotics (LAI-APs) are considered a major advance in psychiatric treatment concerning treatment adherence and outcomes. Yet, both, doctors and patients remain sceptical.

AIM

To explain the rationale for using LAI-APs, review their effectiveness and explore barriers to use.

METHOD

Clinical overview of LAI-APs from the patient and doctor's perspective.

RESULTS

LAI-APs were developed to increase adherence to treatment, thereby improving treatment outcomes. LAI-APs may reduce the risk of relapse and hospitalisation. Yet, the evidence from the few meta-analyses available remains weak. Both patients and doctors may associate LAI-APs with stigma and coercion. Current means of improving adherence include more focus on the therapeutic relationship, better information, adverse effects minimisation and half-life extension of LAI-APs. Future means of improving adherence include novel administration techniques that abolish the need for injection.

CONCLUSIONS

For both, clinicians and drug developers, drug adherence remains a major target for improving treatment outcomes.

Mixed cationic liposomes for brain delivery of drugs by the intranasal route: The acetylcholinesterase reactivator 2-PAM as encapsulated drug model

New mixed cationic liposomes based on L-α-phosphatidylcholine and dihexadecylmethylhydroxyethylammonium bromide (DHDHAB) were designed to overcome the BBB crossing by using the intranasal route. Synthesis and self-assembly of DHDHAB were performed. A low critical association concentration (0.01 mM), good solubilization properties toward hydrophobic dye Orange OT and antimicrobial activity against gram-positive bacteria Staphylococcus aureus (MIC=7.8 μg mL^-1) and Bacillus cereus (MIC=7.8 μg mL^-1), low hemolytic activities against human red blood cells (less than 10%) were achieved. Conditions for preparation of cationic vesicles and mixed liposomes with excellent colloidal stability at room temperature were determined. The intranasal administration of rhodamine B-loaded cationic liposomes was shown to increase bioavailability into the brain in comparison to the intravenous injection. The cholinesterase reactivator, 2-PAM, was used as model drug for the loading in cationic liposomes. 2-PAM-loaded cationic liposomes displayed high encapsulation efficiency (∼ 90%) and hydrodynamic diameter close to 100 nm. Intranasally administered 2-PAM-loaded cationic liposomes were effective against paraoxon-induced acetylcholinesterase inhibition in the brain. 2-PAM-loaded liposomes reactivated 12 ± 1% of brain acetylcholinesterase. This promising result opens the possibility to use marketed positively charged oximes in medical countermeasures against organophosphorus poisoning for reactivation of central acetylcholinesterase by implementing a non-invasive approach, via the "nose-brain" pathway.

Cranial Pair I: The Olfactory Nerve

The olfactory nerve constitutes the first cranial pair. Compared with other cranial nerves, it depicts some atypical features. First, the olfactory nerve does not form a unique bundle. The olfactory axons join other axons and form several small bundles or fascicles: the fila olfactoria. These fascicles leave the nasal cavity, pass through the lamina cribrosa of the ethmoid bone and enter the brain. The whole of these fascicles is what is known as the olfactory nerve. Second, the olfactory sensory neurons, whose axons integrate the olfactory nerve, connect the nasal cavity and the brain without any relay. Third, the olfactory nerve is composed by unmyelinated axons. Fourth, the olfactory nerve contains neither Schwann cells nor oligodendrocytes wrapping its axons. But it contains olfactory ensheathing glia, which is a type of glia unique to this nerve. Fifth, the olfactory axons participate in the circuitry of certain spherical structures of neuropil that are unique in the brain: the olfactory glomeruli. Sixth, the axons of the olfactory nerve are continuously replaced and their connections in the central nervous system are remodeled continuously. Therefore, the olfactory nerve is subject to lifelong plasticity. Finally seventh, the olfactory nerve can be a gateway for the direct entrance of viruses, neurotoxins and other xenobiotics to the brain. In the same way, it can be used as a portal of entry to the brain for therapeutic substances, bypassing the blood-brain barrier. In this article, we analyze some features of the anatomy and physiology of the first cranial pair. Anat Rec, 302:405-427, 2019. © 2018 Wiley Periodicals, Inc.