CNS Drug Research Articles

Stimulation of Vagus By Phenylephrine Increases the Efficiency and Safety of Antidepressants and Anti-Epileptics

Background: Earlier, we discovered the possibility of potentiation of the therapeutic effects of small (threshold) doses of CNS agents by phenylephrine and adrenaline, while eliminating their side effects. However, the question of the possibility of potentiation by phenylephrine and other CNS potentiators of high therapeutic doses of CNS agents remained unstudied. This study is devoted to the research of this problem. Objective: The aim of the study was to investigate the effect of the threshold dose of phenylephrine on the antidepressant effect of amitriptyline and the anticonvulsant effect of diazepam, as well as their side sedation in high doses. Method: The experiments were carried out on the animated models of depression (Porsolt test) and epilepsy (clonic pentylenetetrazole (PTZ)-induced seizures), resistant to antidepressants and antiepileptics even at high therapeutic doses. Side sedative effect of substances was evaluated in the "open field" test. Results: We established that the stimulation of gastric vagal afferents with phenylephrine, when administered orally at threshold doses, potentiates the anticonvulsant effect of diazepam and the antidepressant effect of amitriptyline in high therapeutic doses to the maximum level that is impossible in their application by themselves, and at the same time eliminates their side sedation. Conclusion: A synergistic effect of phenylephrine and CNS drugs on the peripheral and central links of the vagal stress-protective reflex is discussed. It is assumed that the potentiation of therapeutic effect by phenylephrine and the elimination of side effects of the CNS agents occurs as a result of strengthening the vagal stress-protective reflex, eliminating the drug stress.

Exclusion of unsuitable CNS drug candidates based on their physicochemical properties and unbound fractions in biomatrices for brain microdialysis investigations

Microdialysis has been the only direct method of continuously measuring the unbound drug concentrations in extracellular fluid at a specific brain region with respect to time in the same animal. However, not every compound is suitable for microdialysis system as demonstrated by their inconsistent “by gain” and “by loss” in-vitro microdialysis probe recoveries leading to over- or under- estimated in-vivo concentrations. Therefore, our current study was proposed aiming to develop simple exclusion criteria for drug candidates that are not suitable for microdialysis system investigation. Through literature research, the properties ((LogP, pKa, water solubility and unbound fraction in plasma and brain) of drugs that have been reported for microdialysis studies were summarized. The exclusion criteria were developed by evaluating the impact of such properties on the consistency of in-vitro “by gain” and “by loss” recoveries of microdialysis probe. As a result, forty-five compounds were identified from literatures, among which doxorubicin, docetaxel, omeprazole, donepezil and phenytoin were found to have inconsistent in-vitro “by gain” and “by loss” microdialysis probe recoveries and subsequently selected for the exclusion criteria analysis. It was found that compounds with limited water solubility (less than 1 g/L) and unbound fraction in plasma (fu,plasma less than 30%) and brain homogenate (fu,brain less than 10%) were more likely to have inconsistent “by gain” and “by loss” microdialysis probe recoveries. Our proposed exclusion criteria were further validated using carbamazepine (limited water solubility only), DB213 (limited fu,brain only) and piperine (both limited water solubility and limited fu,plasma, fu,brain). Our current proposed exclusion criteria will help excluding the CNS drug candidates that are highly unlikely suitable for brain microdialysis approach leading to a better success rate in brain microdialysis approach development.

Sex differences in adult zebrafish anxiolytic-like responses to diazepam and melatonin

Sex differences are an important variable in biomedical research. The zebrafish (Danio rerio) is rapidly becoming a critical novel model organism in translational neuroscience and neuropharmacology. Here, we examine the effects of sex on locomotor activity and anxiety-like behavior in adult zebrafish tested in the novel tank test following their exposure to two clinically relevant, common anxiolytic drugs diazepam and melatonin. While control female zebrafish were more active and anxious than males, both sexes showed anxiolytic responses to melatonin (0.232 mg/L) but only males responded to diazepam (16 μg/L). Revealing sex specificity in pharmacological responses, this study emphasizes the importance of sex differences in behavioral and pharmacological analyses in zebrafish. This may also be potentially relevant to modeling sex differences in clinical responses to anxiolytic drugs. Collectively, our data support sex differences in zebrafish behavioral responses and reinforce the growing utility of this aquatic model in CNS drug screening.

P2.14-69 Lorlatinib Rescue Therapy for Life Threatening CNS Disease in Crizotinib-Resistant ROS1-Positive Non–Small Cell Lung Cancer (NSCLC)

C-ros proto-oncogene-1 (ROS1) chromosomal translocations result in constitutively activated receptor tyrosine kinase in 1-2% of NSCLC. Although crizotinib, a first-generation Tyrosine Kinase Inhibitor (TKI) of Anaplastic Lymphoma Kinase (ALK) and ROS1 translocations, has demonstrated efficacy in treatment of ROS1 NSCLC, patients invariably acquire resistance mutations, with a high incidence of brain metastasis at relapse owing to poor CNS drug penetration. Lorlatinib is a novel, third-generation TKI with improved CNS penetration and preclinical activity against crizotinib-resistance mutations, which recently demonstrated efficacy in a phase I/II trial. We report a patient who developed secondary crizotinib-resistance and was successfully treated with lorlatinib. A 73-year-old, female, never-smoker with recently diagnosed stage-IV ROS1-rearranged NSCLC presented with refractory seizures and coma. The patient was on first-line treatment with crizotinib for 6-months, with an excellent systemic response at 2 months. Brain MRI after presentation demonstrated multiple intracranial metastasis with vasogenic edema (Fig.1A). Neurologic status was unchanged despite mannitol, steroids and anti-epileptics. As salvage therapy, the patient received bevacizumab for vasogenic edema and lorlatinib (100mg/daily). After 48-hours, substantial clinical improvement in neurologic function and mental status was observed. A repeat MRI (D+4) demonstrated a slight interval decrease in the largest metastasis and associated edema. At 1-month follow-up, the patient continued to improve clinically with no evidence of lorlatinib toxicity. Brain MRI showed a decrease in the sizes and/or resolution of all previously noted lesions and no new metastases or significant peritumoral edema (Fig.1B). Since clinical trials typically exclude patients with symptomatic, untreated CNS disease, efficacy of newer, targeted agents in mutated-NSCLC is unclear. Here we report on a patient with life threatening, acute neurologic deterioration who derived a meaningful clinical reduction in CNS lesions at 1 month, with favorable CNS response at 2 months. In addition, we observed early evidence of tumor regression on MRI after 4 days of lorlatinib therapy. Of note, her rapid clinical response may have in part been attributable to the addition of bevacizumab. Another important consideration for our patient is that she avoided whole-brain radiation in the acute setting, and its potential adverse sequalae. We note a limitation was the absence of available testing for secondary resistance mutations that developed in this patient, which was highly susceptible to lorlatinib. However, current clinical guidelines (NCCN) do not specifically recommend resistance mutation testing upon progression, and outside of a clinical trial, the current algorithm supports lorlatinib as the agent of choice post-crizotinib failure.

Validation of Cadherin HAV6 Peptide in the Transient Modulation of the Blood-Brain Barrier for the Treatment of Brain Tumors.

The blood-brain barrier (BBB) poses a major obstacle by preventing potential therapeutic agents from reaching their intended brain targets at sufficient concentrations. While transient disruption of the BBB has been used to enhance chemotherapeutic efficacy in treating brain tumors, limitations in terms of magnitude and duration of BBB disruption exist. In the present study, the preliminary safety and efficacy profile of HAV6, a peptide that binds to the external domains of cadherin, to transiently open the BBB and improve the delivery of a therapeutic agent, was evaluated in a murine brain tumor model. Transient opening of the BBB in response to HAV6 peptide administration was quantitatively characterized using both a gadolinium magnetic resonance imaging (MRI) contrast agent and adenanthin (Ade), the intended therapeutic agent. The effects of HAV6 peptide on BBB integrity and the efficacy of concurrent administration of HAV6 peptide and the small molecule inhibitor, Ade, in the growth and progression of an orthotopic medulloblastoma mouse model using human D425 tumor cells was examined. Systemic administration of HAV6 peptide caused transient, reversible disruption of BBB in mice. Increases in BBB permeability produced by HAV6 were rapid in onset and observed in all regions of the brain examined. Concurrent administration of HAV6 peptide with Ade, a BBB impermeable inhibitor of Peroxiredoxin-1, caused reduced tumor growth and increased survival in mice bearing medulloblastoma. The rapid onset and transient nature of the BBB modulation produced with the HAV6 peptide along with its uniform disruption and biocompatibility is well-suited for CNS drug delivery applications, especially in the treatment of brain tumors.

Functional ultrasound – Novel in-vivo imaging technique for pre-clinical CNS drug discovery

Functional ultrasound – Novel in-vivo imaging technique for pre-clinical CNS drug discovery

Carbamoylated erythropoietin produces antidepressant-like effects in male and female mice

Major depressive disorder and related illnesses are globally prevalent, with a significant risk for suicidality if untreated. Antidepressant drugs that are currently prescribed do not benefit 30% of treated individuals. Furthermore, there is a delay of 3 or more weeks before a reduction in symptoms. Results from preclinical studies have indicated an important role for trophic factors in regulating behavior. Erythropoietin (Epo), which is widely prescribed for anemia, has been shown to produce robust neurotrophic actions in the CNS. Although Epo's antidepressant activity has been successfully demonstrated in multiple clinical trials, the inherent ability to elevate RBC counts and other hematological parameters preclude its development as a mainstream CNS drug. A chemically engineered derivative, carbamoylated Epo (Cepo) has no hematological activity, but retains the neurotrophic actions of Epo. Cepo is therefore an attractive candidate to be tested as an antidepressant. Objective: To evaluate the antidepressant properties of Cepo in established antidepressant-responsive rodent behavioral assays. Methods: Adult male and female BALB/c mice were used for this study. Cepo (30 μgrams/ kg BWT) or vehicle (PBS) was administered intraperitoneally for 4 days before the test of novelty induced hypophagia and subsequently at five hours before testing in forced swim test (FST), tail suspension test (TST) and open field test (OFT). To obtain mechanistic insight we examined the phosphorylation of the transcription factor cAMP response element binding protein (CREB).Results: Administration of Cepo at 30 μgrams/ kg BWT, for 4 days produced significant reduction in latency to consume a palatable drink in a novel environment in male and female mice. Male BALB/c mice had a significant reduction in immobility in both tail suspension and forced swim tests, and female mice exhibited lower immobility in the forced swim test.

Streptococcus agalactiae disrupts P-glycoprotein function in brain endothelial cells

Bacterial meningitis is a serious life threatening infection of the CNS. To cause meningitis, blood–borne bacteria need to interact with and penetrate brain endothelial cells (BECs) that comprise the blood–brain barrier. BECs help maintain brain homeostasis and they possess an array of efflux transporters, such as P-glycoprotein (P-gp), that function to efflux potentially harmful compounds from the CNS back into the circulation. Oftentimes, efflux also serves to limit the brain uptake of therapeutic drugs, representing a major hurdle for CNS drug delivery. During meningitis, BEC barrier integrity is compromised; however, little is known about efflux transport perturbations during infection. Thus, understanding the impact of bacterial infection on P-gp function would be important for potential routes of therapeutic intervention. To this end, the meningeal bacterial pathogen, Streptococcus agalactiae, was found to inhibit P-gp activity in human induced pluripotent stem cell-derived BECs, and live bacteria were required for the observed inhibition. This observation was correlated to decreased P-gp expression both in vitro and during infection in vivo using a mouse model of bacterial meningitis. Given the impact of bacterial interactions on P-gp function, it will be important to incorporate these findings into analyses of drug delivery paradigms for bacterial infections of the CNS.

Neuronal Circuit-Based Computer Modeling as a Phenotypic Strategy for CNS R&D.

With the success rate of drugs for CNS indications at an all-time low, new approaches are needed to turn the tide of failed clinical trials. This paper reviews the history of CNS drug Discovery over the last 60 years and proposes a new paradigm based on the lessons learned. The initial wave of successful therapeutics discovered using careful clinical observations was followed by an emphasis on a phenotypic target-agnostic approach, often leading to successful drugs with a rich pharmacology. The subsequent introduction of molecular biology and the focus on a target-driven strategy has largely dominated drug discovery efforts over the last 30 years, but has not increased the probability of success, because these highly selective molecules are unlikely to address the complex pathological phenotypes of most CNS disorders. In many cases, reliance on preclinical animal models has lacked robust translational power. We argue that Quantitative Systems Pharmacology (QSP), a mechanism-based computer model of biological processes informed by preclinical knowledge and enhanced by neuroimaging and clinical data could be a new powerful knowledge generator engine and paradigm for rational polypharmacy. Progress in the academic discipline of computational neurosciences, allows one to model the effect of pathology and therapeutic interventions on neuronal circuit firing activity that can relate to clinical phenotypes, driven by complex properties of specific brain region activation states. The model is validated by optimizing the correlation between relevant emergent properties of these neuronal circuits and historical clinical and imaging datasets. A rationally designed polypharmacy target profile will be discovered using reverse engineering and sensitivity analysis. Small molecules will be identified using a combination of Artificial Intelligence methods and computational modeling, tested subsequently in heterologous cellular systems with human targets. Animal models will be used to establish target engagement and for ADME-Tox, with the QSP approach complemented by in vivo preclinical models that can be further refined to increase predictive validity. The QSP platform can also mitigate the variability in clinical trials with the concept of virtual patients. Because the QSP platform integrates knowledge from a wide variety of sources in an actionable simulation, it offers the possibility of substantially improving the success rate of CNS R&D programs while, at the same time, reducing both cost and the number of animals.

Challenging the CNS Targeting Potential of Systemically Administered Nanoemulsion Delivery Systems: a Case Study with Rapamycin-Containing Fish Oil Nanoemulsions in Mice.

Despite extensive preclinical investigations, in-vivo properties and formulation characteristics that improve CNS drug delivery following systemic dosing of nanoemulsions remain incompletely understood. The CNS targeting potential of systemically administered nanoemulsions was evaluated by formulating rapamycin containing fish oil nanoemulsions, and testing the combined effect of formulation characteristics such as the circulation half-life and particle size distribution, on CNS delivery of rapamycin containing fish oil nanoemulsions in mice. Results generated with rapamycin nanoemulsions suggested that circulation half-life and particle size distribution did not impact the brain targeting efficiency of rapamycin containing fish oil nanoemulsions. Further, in the absence of any improvement in the systemic exposures of rapamycin, nanoemulsions did not outperform their aqueous counterpart with respect to the extent of CNS drug delivery. Our findings confirm that BBB penetration, which primarily depends on intrinsic drug-related properties, may not be significantly improved following encapsulation of drugs in nanoemulsions. Graphical Abstract The CNS targeting potential of systemically administered nanoemulsions was investigated by formulating various rapamycin containing fish oil nanoemulsions associated with different formulation characteristics such as the circulation half-life and particle size distribution. The targeting efficiency (TE) defined as the ratio of the brain exposures to the accompanying systemic exposures of rapamycin was estimated for each formulation following IV dosing in mice.

035 Valproate-induced parkinsonism ‘an early warning’: case reports and review of literature

IntroductionWe describe two cases of valproate-induced parkinsonism, where the parkinsonian features develop after commencing valproate (VPA), in a time frame and manner well described by previous publications.1 In contrast to the published literature, that has short duration of follow-up, we have had a prolonged follow-up of these two cases, who initially improved on ceasing valproate, but then after a period progressed again, with the development of levodopa-responsive asymmetrical Parkinson’s disease.2Cases67 years old man, on VPA 500 mg twice a day for seizures since 2008, developed new rest, re-emergent left hand tremor and hypomimia in 2012. Within months, the parkinsonism progressed to decremental bradykinesia, cog-wheel rigidity and hypophonia. The symptoms initially improved with changing VPA to levetiracetam; however, the disease reappeared after 6 months and although levodopa-responsive, it has been progressive since then.88 years old man, on VPA 700 mg twice a day for seizures since 2010, developed upper limb decremental bradykinesia, cog-wheel rigidity, camptocormia and rest, re-emergent tremor in hands in 2011. The parkinsonism improved significantly with cessation of VPA; however, the disease re-emerged after 2 years and has been progressive since then.ConclusionVPA may be responsible for unmasking underlying subclinical parkinsonism and these patients represent an earlier onset of Parkinson’s disease related to VPA exposure, rather than a purely drug related parkinsonian dysfunction. These cases also highlight the importance of long-term follow up in VPA-induced parkinsonism. These observations are an important consideration for clinicians treating patients with parkinsonian features secondary to VPA exposure.ReferencesBrugger F, Bhatia KP, Besag FM. Valproate-associated parkinsonism: a critical review of the literature. CNS Drugs 2016;30(6):527–540.Mahmoud F, Tampi RR. Valproic acid-induced parkinsonism in the elderly: a comprehensive review of the literature. Am J Geriatr Pharmacother 2011;9(6):405–412.

HYDROQUINONE: A novel growth inhibitor and apoptosis inducer in U-251 MG CELLS

In design of new CNS drugs, profound and selective cytotoxicity, penetration through the blood brain barrier along with lack of neurotoxic effects coupled with no side effects in humans at a dose of 3 mg/kg administered actually make the avarol chemical scaffold (Figure 1) an ideal candidate [1]. This study aimed to screen in vitro structure-activity relationship (along with selectivity) using avarol (followed by its structural elements) and the human malignant glioma U-251 MG cells

The ANKS1B gene and its associated phenotypes: focus on CNS drug response.

The ANKS1Bgene was a top finding in genome-wide association studies (GWAS)of antipsychotic drug response. Subsequent GWAS findings for ANKS1B include cognitive ability, educational attainment, body mass index, response to corticosteroids and drug dependence. We review current human association evidence for ANKS1B, in addition to functional studies that include two published mouse knockouts. The several GWAS findings in humans indicate that phenotypically relevant variation is segregating at the ANKS1B locus. ANKS1B shows strong plausibility for involvement in CNS drug response because it encodes a postsynaptic effector protein that mediates long-term changes to neuronal biology. Forthcoming data from large biobanks should further delineate the role of ANKS1B in CNS drug response.

Advances in CNS drug development

Advances in CNS drug development

Prospects for repurposing CNS drugs for cancer treatment.

Drug repurposing is the idea of using an already approved drug for another disease or disorder away from its initial use. This new approach ensures the reduction in high cost required for developing a new drug in addition to the time consumed, especially in the tumor disorders that show an unceasing rising rate with an unmet success rate of new anticancer drugs. In our review, we will review the anti-cancer effect of some CNS drugs, including both therapeutic and preventive, by searching the literature for preclinical or clinical evidence for anticancer potential of central nervous system drugs over the last 8 years period (2010-2018) and including only evidence from Q1 journals as indicated by Scimago website (www.scimagojr.com). We concluded that Some Central Nervous system drugs show a great potential as anti-cancer in vitro, in vivo and clinical trials through different mechanisms and pathways in different types of cancer that reveal a promising evidence for the repurposing of CNS drugs for new indications.

A futuristic perspective in subsiding the symptoms of Parkinson’s Disease

Parkinson's disease (PD) is a neurodegenerative disorder that primarily impinges the dopaminergic neurons in a particular region of Brain termed as Substantia Nigra. The disease affects more than 1900 people per 100,000 aged 80 years and above. Furthermore, men are 1.5 times more prone than their counterpart. Potential biomarkers escalated the precise diagnosis and helped to initiate treatment to limit its adversity. The current therapeutic schemes are focused on administration of Dopamine precursor, Dopamine agonist, Monoamine oxidase (MAO) inhibitor, Catechol-o-methyl transferase (COMT) inhibitors and deep brain stimulation. The CNS delivery focuses mainly on increasing the dopamine level in the brain. CNS drug delivery faces a crucial challenge of crossing Blood Brain Barrier. Blood-Brain Barrier Penetration can be attained by several techniques. Conventional drug therapy yields harmful affects to the patients without much therapeutics. It is visible that crossing BBB is quite strenuous process. It is mandatory for developing a novel approach untangling these situations. Nanotechnology-based formulations like nanosuspensions, nanotubes etc. promotes the penetration of drug across the sophisticated barrier without creating any deterioration to cells or organs. Several novel routes for drug administration reduce dose intake with increased and precise pharmacological action. Nanoformulations and Novel routes of drug administration are a promising tool to enhance the action of drug which helps to abate the symptoms of the Disease and assist in the betterment in treatment.

Microwave-assisted synthesis and in vitro stability of N-benzylamide non-steroidal anti-inflammatory drug conjugates for CNS delivery

More effective delivery of non-steroidal anti-inflammatory drugs (NSAIDs) to the brain could treat the underlying inflammatory pathology of a range of CNS diseases and conditions. Use of a blood-brain barrier shuttle such as the N-benzylamide moiety, which has been largely unexplored for this purpose, could improve the brain bioavailabilities of NSAIDs. A series of novel N-benzylamide NSAID conjugates was synthesized via a three-step process with a microwave-assisted bimolecular nucleophilic substitution as the final step. We explored conditions to promote substitution over a competing elimination reaction, which was successfully suppressed with isopropyl alcohol solvent. All molecules exhibit physicochemical properties consistent with those of brain-penetrant molecules. Furthermore, they exhibit long (>48 h) half-lives in phosphate-buffered saline (PBS; pH 7.4) and short to moderate half-lives in human plasma. N-Benzylamide NSAID conjugates represent promising CNS drug discovery leads.

Functional Ultrasound

Genetic Engineering & Biotechnology NewsVol. 39, No. 4 Drug Discovery TutorialFunctional UltrasoundCharles River Laboratories’ novel in vivo imaging technique for preclinical CNS drug discoveryArtem Shatillo, Juho Koponen, Tuukka Miettinen, Anna-Mari Karkkainen, and Antti NurmiArtem ShatilloArtem Shatillo (E-mail Address: Artem.Shatillo@crl.com), MD, PhD, is head of imaging, Juho Koponen serves as research associate, Tuukka Miettinen is a research associate, Anna-Mari Karkkainen serves as study director, and Antti Nurmi, PhD, is managing director, discovery services, at Charles River Finland. Website: www.criver.com.Search for more papers by this author, Juho KoponenArtem Shatillo (E-mail Address: Artem.Shatillo@crl.com), MD, PhD, is head of imaging, Juho Koponen serves as research associate, Tuukka Miettinen is a research associate, Anna-Mari Karkkainen serves as study director, and Antti Nurmi, PhD, is managing director, discovery services, at Charles River Finland. Website: www.criver.com.Search for more papers by this author, Tuukka MiettinenArtem Shatillo (E-mail Address: Artem.Shatillo@crl.com), MD, PhD, is head of imaging, Juho Koponen serves as research associate, Tuukka Miettinen is a research associate, Anna-Mari Karkkainen serves as study director, and Antti Nurmi, PhD, is managing director, discovery services, at Charles River Finland. Website: www.criver.com.Search for more papers by this author, Anna-Mari KarkkainenArtem Shatillo (E-mail Address: Artem.Shatillo@crl.com), MD, PhD, is head of imaging, Juho Koponen serves as research associate, Tuukka Miettinen is a research associate, Anna-Mari Karkkainen serves as study director, and Antti Nurmi, PhD, is managing director, discovery services, at Charles River Finland. Website: www.criver.com.Search for more papers by this author, and Antti NurmiArtem Shatillo (E-mail Address: Artem.Shatillo@crl.com), MD, PhD, is head of imaging, Juho Koponen serves as research associate, Tuukka Miettinen is a research associate, Anna-Mari Karkkainen serves as study director, and Antti Nurmi, PhD, is managing director, discovery services, at Charles River Finland. Website: www.criver.com.Search for more papers by this authorPublished Online:29 Mar 2019https://doi.org/10.1089/gen.39.04.16AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 39Issue 4Apr 2019 InformationCopyright © GEN PublishingTo cite this article:Artem Shatillo, Juho Koponen, Tuukka Miettinen, Anna-Mari Karkkainen, and Antti Nurmi.Functional Ultrasound.Genetic Engineering & Biotechnology News.Apr 2019.52-54.http://doi.org/10.1089/gen.39.04.16Published in Volume: 39 Issue 4: March 29, 2019PDF download

Mathematical Modeling and Simulation to Investigate the CNS Transport Characteristics of Nanoemulsion-Based Drug Delivery Following Intranasal Administration.

Despite encouraging preclinical results, mechanisms of CNS drug delivery following intranasal dosing of nanoemulsions remain incompletely understood. Herein, the transport characteristics of intranasally administered nanoemulsions are investigated using mathematical modeling and simulation. A compartmental model was developed to describe systemic and brain pharmacokinetics of drug solutions following intranasal dosing in rodents. The association between transport processes and CNS drug delivery was predicted using sensitivity analysis. Published pharmacokinetic data for four drugs; dosed as a nanoemulsion and aqueous solution were modeled to characterize differences in transport processes across formulations. The intranasal model structure performed in a drug agnostic fashion. Sensitivity analysis suggested that though the extent of CNS drug delivery depends on nasal bioavailability, the CNS targeting efficiency is only sensitive to changes in drug permeability across the nasal epithelium. Modeling results indicated that nanoemulsions primarily improve nasal bioavailability and drug permeability across the olfactory epithelium, with minimal effect on drug permeability across the non-olfactory epithelium. Using mathematical modeling we outlined dominant transport pathways following intranasal dosing, predicted the association between transport pathways and CNS drug delivery, predicted human CNS delivery after accounting for inter-species differences in nasal anatomy, and quantified the CNS delivery potential of different formulations in rodents.

Multikinase Abl/DDR/Src Inhibition Produces Optimal Effects for Tyrosine Kinase Inhibition in Neurodegeneration.

Background and objectivesInhibition of Abelson (Abl) tyrosine kinase as a therapeutic target has been gaining attention in neurodegeneration. Post-mortem Alzheimer’s and Parkinson’s disease brains show that the levels of several other tyrosine kinases, including Discoidin Domain Receptors (DDR1/2) are elevated. Knockdown of these tyrosine kinases with shRNA reduces neurotoxic proteins, including alpha-synuclein, beta-amyloid and tau.MethodsDirect profiling of the pharmacokinetics of multi-kinase inhibitors Nilotinib, Bosutinib, Bafetinib, Radotinib and LCB-03-0110 shows differential levels of brain penetration but the ability of these agents to reduce toxic proteins is independent of brain concentration and selectivity to Abl.ResultsOur results indicate that the effective dose of Nilotinib has the lowest plasma:brain ratio (1%) followed by Bosutinib and Radotinib (5%), Bafetinib (12%) and LCB-03-0110 (12%). However, similar doses of multi-kinase Abl/DDR inhibitor Nilotinib, DDR/Src inhibitor LCB-03-0110 and Abl/Src inhibitor Bosutinib were much more effective than the more selective Abl inhibitors Radotinib and Bafetinib. Taken together, these data suggest that a multi-kinase target that includes Abl and other tyrosine kinases (DDRs, and Src) may offer more advantages alleviating neurodegenerative pathologies than the absolute CNS drug concentration and selectivity to Abl.ConclusionDDRs and Src are other potential co-targets with Abl in neurodegeneration.Electronic supplementary materialThe online version of this article (10.1007/s40268-019-0266-z) contains supplementary material, which is available to authorized users.