Drug Concentrations In Brain Research Articles

Human CYP2D6 varies across the estrous cycle in brains of transgenic mice altering drug response

Cytochrome P450 (CYP) 2Ds are drug metabolizing enzymes found in brain and liver which metabolize numerous centrally acting drugs. Inhibition and induction of CYP2D-mediated metabolism in rodent brain alters brain drug and metabolite concentrations and resulting drug response. In female rats, brain CYP2D metabolism varies across the estrous cycle and with exogenous estrogen, changing brain drug concentrations and response.In this study harmine-induced hypothermia was lower in humanized CYP2D6 transgenic female mice during estrus compared to diestrus. Pretreatment into the cerebral ventricles with propranolol, a selective irreversible inhibitor of human CYP2D6 in brain, increased hypothermia in estrus but not in diestrus. In vivo enzyme activity was higher in brains of transgenic mice in estrus compared to diestrus and was lower after pretreatment with inhibitor in estrus, but not in diestrus. Hepatic activity and plasma harmine concentrations were unaffected by either estrous phase or inhibition of brain CYP2D6. In wild-type female mice, harmine-induced hypothermia was unaffected by either estrous phase or inhibitor pretreatment. Male mice were used as positive controls, where pretreatment with inhibitor increased harmine-induced hypothermia in transgenic but not wild-type, mice.This study provides evidence for female hormone cycle-based regulation of drug metabolism by human CYP2D6 in brain and resulting drug response. This suggests that brain CYP2D6 metabolism may vary, for example, during the menstrual cycle, pregnancy, or menopause, or while taking oral contraceptives or hormone therapy. This variation could contribute to individual differences in response to centrally acting CYP2D6-substrate drugs by altering local brain drug and/or metabolite concentrations.

Nose to brain delivery of escitalopram-loaded nano-structured lipid carriers thermosensitive gel: Formulation, physiochemical, pharmacokinetic and pharmacodynamics evaluation

The primary focus of the undertaken research was to design and develop poloxamer-based thermosensitive gel system of escitalopram-loaded nano-structured lipid carriers (ESC-NLCs gel) for nose to brain delivery. ESC-NLCs were optimized using Design Expert® (Version 12). The optimized formulation was encompassed in poloxamer-based thermosensitive gel and was characterized accordingly. In vitro release, ex vivo permeation and in vivo brain and plasma pharmacokinetics was investigated. Additionally, behavioral analysis of the lipopolysaccharide (LPS) induced depressed rats was performed followed by immunohistochemistry of the brain hippocampus and cortex regions. Particle size, polydispersity index and zeta potential of the optimized ESC-NLCs were respectively found as 131 nm, 0.278 and −24.9 mV with excellent entrapment efficiency (96 %). The optimized formulation showed suitable morphology, optimum thermal behavior, amorphous nature and drug-excipient compatibility. ESC-NLCs gel displayed sustained in vitro release profile, whereas permeation was enhanced 27-folds. Brain pharmacokinetics of ESC-NLCs explored 9 folds increased drug concentration in brain. Similarly, improved behavioral changes and reduced neuro inflammatory markers (NF-κB and TNF-α) were observed in LPS induced depressed rats after treatment with ESC-NLCs gel. It can be concluded that ESC-NLCs gel has the potential to sustain the drug release, improve the permeation and bioavailability and reduce the depression after nose to brain delivery in animal model.

Design Optimization and Pharmacokinetic Study of Eletriptan Hydrobromide Loaded Solid Lipid Nanoparticle Nasal Gel Targeted to Brain

In the present research work, Eletriptan Hydrobromide(E-HBr)-loaded solid lipid nanoparticles (SLN’s) incorporated in a gel was prepared by emulsification solvent evaporation technique to enhance the uptake of E-HBr to brain via intra-nasal (i.n.) route and the formulations were evaluated for particle size, polydispersibility index, zeta potential, drug entrapment efficiency, in-vitro drug release, and stability of the optimized formulation. All the parameters evaluated were within the acceptable range. In-vitro drug release for the optimized gel formulation was found to be 92.45% after 12hr and was fitted to the Higuchi model with a very high correlation coefficient (R2=0.995). Pharmacokinetics studies were performed on albino male Wistar rats and the concentration of E-HBr in brain and blood plasma was measured by HPLC. The brain/blood ratio at 0.5h for E-HBr Opt.SLN’s i.n., E-HBr sol. i.n., and E-HBr sol. oral. were found to be 2.35, 1.19 and 0.80 respectively, indicating the drug transported directly from nose-to-brain, by bypassing the blood–brain barrier in the olfactory region present in the nasal cavity. The maximum concentration of drug in brain (Cmax) after i.n. administration of E-HBr-SLN gel was found to be (21465.87±1110.66ng/ml, Tmax 8.45hr) significantly higher than that achieved after oral administration (6797.23±842.86ng/ml, Tmax 7hr), and i.n. (16451.53±3792.40ng/ml, Tmax 7.69 hr) administration of E-HBr sol. The highest drug-targeting efficiency (2.35%) and direct transport percentage (66.05%) was found with E-HBr-SLN’s as compared to the other formulations. Higher DTE (%) and DTP (%) suggest, that E-HBr-SLN gel had better brain targeting efficiency as compared to other formulations.

Abstract LB174: OKI-219 is an inhibitor of PI3Kα H1047R that has brain penetrance and anti-tumor activity in a preclinical intracranial model of metastatic breast cancer

Abstract Background: Dysregulation of PI3K signaling is a common driver of solid tumors, with the PI3KαH1047R activating mutation found in 4% of all cancers. Because many cancers, including breast and lung cancers, can metastasize to the CNS, brain penetration should be a key feature of new therapies. The FDA-approved PI3K inhibitor alpelisib lacks CNS activity, and brain-penetrant alternatives such as buparlisib and paxalasib were not approved due to toxicity associated with a lack of mutant selectivity. OKI-219 is a potent, highly selective PI3KαH1047R inhibitor that has shown preclinical anti-tumor activity in multiple cancer models, both as a monotherapy and in combination with HER2- and ER-mediated therapeutics. Here, we demonstrate its brain penetrance across multiple animal species and anti-tumor activity in an intracranial mouse model of PI3KαH1047R mutant breast cancer. Materials and methods: Brain penetrance in mouse, rat, dog, and monkey was quantified by the ratio of unbound drug concentrations in brain to plasma (Kp,uu). Plasma, brain, and cerebrospinal fluid (CSF) concentrations of OKI-219 were measured by LC/MS, and protein binding in plasma, CSF, and brain homogenate were measured by rapid equilibrium dialysis. Additionally, free drug levels in the brain were directly measured by microdialysis in rats. Mice were implanted subcutaneously and intracranially with PI3KαH1047R xxT47D-luc tumors and tumor growth was measured by calipers (subcutaneous tumors) and luminescence (intracranial tumors). Results: At the Cmax of a pharmacologically active 10 mg/kg PO dose, OKI-219 had a Kp,uu of 0.34, 0.61, and 0.58 in rat, dog, and monkey CSF, respectively. Additionally, OKI-219 had an average Kp,uu of 0.67 over 24h post-dose as measured by brain microdialysis in rats at 30 mg/kg, with a dose-proportionate increase in brain free drug levels at 300 mg/kg. After 21 days of treatment, OKI-219 induced a statistically significant dose-dependent anti-tumor effect on both flank and brain xxT47D-luc tumors. Conclusion: Here we show that OKI-219 had consistently good brain penetrance across multiple species by multiple methods of measuring free drug levels in the brain. We further demonstrated that OKI-219 had anti-tumor activity against xxT47D-luc tumors in an intracranial mouse model that is similar to activity in the same tumor when implanted subcutaneously, demonstrating that the brain levels achieved were pharmacologically active. These data indicate the potential for activity of OKI-219 in CNS disease settings, including metastatic brain cancer, which are not currently addressed with existing PI3K pathway inhibitors. OnKure has initiated the PIKture Phase I clinical study (OKI-219-101) to evaluate OKI-219 in patients with PI3KαH1047R-mutated solid tumors. Citation Format: Alexander A. Strait, Molly A. Taylor, Kevin S. Litwiler, Qian Zhao, David A. Mareska, Mark L. Boys, Yevgeniy Izrayelit, Richard Woessner, James D. Winkler. OKI-219 is an inhibitor of PI3Kα H1047R that has brain penetrance and anti-tumor activity in a preclinical intracranial model of metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB174.

Application of machine learning to predict unbound drug bioavailability in the brain

Purpose: Optimizing brain bioavailability is highly relevant for the development of drugs targeting the central nervous system. Several pharmacokinetic parameters have been used for measuring drug bioavailability in the brain. The most biorelevant among them is possibly the unbound brain-to-plasma partition coefficient, Kpuu,brain,ss, which relates unbound brain and plasma drug concentrations under steady-state conditions. In this study, we developed new in silico models to predict Kpuu,brain,ss.Methods: A manually curated 157-compound dataset was compiled from literature and split into training and test sets using a clustering approach. Additional models were trained with a refined dataset generated by removing known P-gp and/or Breast Cancer Resistance Protein substrates from the original dataset. Different supervised machine learning algorithms have been tested, including Support Vector Machine, Gradient Boosting Machine, k-nearest neighbors, classificatory Partial Least Squares, Random Forest, Extreme Gradient Boosting, Deep Learning and Linear Discriminant Analysis. Good practices of predictive Quantitative Structure-Activity Relationships modeling were followed for the development of the models.Results: The best performance in the complete dataset was achieved by extreme gradient boosting, with an accuracy in the test set of 85.1%. A similar estimation of accuracy was observed in a prospective validation experiment, using a small sample of compounds and comparing predicted unbound brain bioavailability with observed experimental data.Conclusion: New in silico models were developed to predict the Kpuu,brain,ss of drug candidates. The dataset used in this study is publicly disclosed, so that the models may be reproduced, refined, or expanded, as a useful tool to assist drug discovery processes.

Abstract 7163: Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain

Abstract Background: Insufficient drug concentrations reaching the brain-localized tumor tissue remains one of the major challenges in the treatment of glioblastoma (GBM). An intranasal (IN) formulation of NEO100 (NeOnc Technologies, Inc., Los Angeles), a highly purified version of perillyl alcohol, has been recently reported to enhance drug concentrations in the brain upon IN co-delivery. Here, we report detailed pharmacokinetics (PK) and tissue analysis to quantitatively examine the extent of increase in drug concentrations in the brain after IN NEO100 administration. Furthermore, we also confirmed that IN NEO100 increases brain drug concentration by circumventing the blood brain barrier. Method: For PK analysis, either IN or oral formulation of a three-drug cocktail (ZEI, consisting of ZN-c3, everolimus, and infigratinib) was used to evaluate the impact of 3% IN NEO100 on the brain penetration profile of the three individual drugs. Athymic mice were grouped into four cohorts to receive 1) oral ZEI; 2) IN ZEI; 3) oral ZEI with IN NEO100; and 4) IN ZEI with IN NEO100. At 2, 4 and 6 hours post ZEI dosing, drug levels in plasma and brain tissue were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). For BBB disruption study, athymic mice were treated with IN delivery of saline (negative control) or 3% NEO100 one hour post intravenous Evans blue (2%) administration. Tumor bearing mice with disrupted BBB served as positive control. Two hours post Evans blue administration, animals were perfused, and brains were collected and sectioned for confocal microscopy to image Evan’s blue autofluorescence. Results: PK analysis revealed that brain-to-plasma ratios (Kp) for ZN-c3, everolimus, and infigratinib remained nearly equal, independent of the route of administration, i.e. 0.11, 0.03, and 0.82 vs 0.09, 0.03, and 0.87, for IN vs oral routes, respectively. Administration of the ZEI together with IN NEO100, either through oral or IN routes, resulted in higher drug concentrations, both in the plasma and in the brain. However, while overall drug exposure was increased, Kp values of the drugs were not changed. Confocal imaging of brains from mice treated with 3% IN NEO100 did not show presence of Evans blue autofluorescence while positive control mice with disrupted BBB within the tumor core displayed high Evans blue fluorescence. Conclusions: Co-administration of IN NEO100 with ZN-c3, everolimus, and infigratinib increases their brain and plasma exposure. As a result, no significant increase in brain-to-plasma partition was registered for any of the three drugs tested in this study. IN NEO100-mediated increase in brain drug concentration was independent of BBB disruption Citation Format: Anil Thaghalli Shivanna, Tigran Margaryan, Mariya Stavnichuk, William Knight, Sonam Patel, Elaine Cabrales, An-Chi Tien, Thomas Chen, Nader Sanai, Artak Tovmasyan, Shwetal Mehta. Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7163.

Polydopamine coated surfactin micelles for brain delivery of ibudilast in multiple sclerosis: Design, optimization, in vitro and in vivo evaluation

Ibudilast inhibits TNF-α and IL-12 release from the astrocytes and microglial cells, reducing neuronal degeneration and may be a potential therapy in multiple sclerosis with neuroprotective effects. Our study aimed to prepare polydopamine coated micelles of surfactin, a biosurfactant, loaded with ibudilast to control the release and its targeted delivery through nose to the brain by targeting D2-like dopamine receptors limited in olfactory nerve of the bulb. Micelles were prepared by solvent evaporation and film hydration method and optimized to quantify the effects of excipients on particle size and entrapment efficiency. Polydopamine coating on the surface of surfactin micelles was characterized by studying the physicochemical properties of the micelles. Drug concentration in brain after 14 days of administration of the oral, and nasal free drug and also 3 doses of intranasal PDA coated micelles of ibudilast were determined by reverse-phase HPLC method. FTIR results confirmed successful coating of PDA on surfactin micelles and DSC and XRD results indicated solubilization of ibudilast in the core of micelles in an amorphous state. The morphology of the micelles by TEM showed spherical structures with coating of PDA on the shell of the micelles. Particle size of the micelles was 131.3 ± 12.6 nm, zeta potential 27.3 ± 1.7 mV, ibudilast loading percent was 90.2 ± 1.6% and drug release efficiency percent was 72.3 ± 6.5% in the best formulation for surfactin micelles. However, after PDA coating the particle size changed to 174.6 ± 15.7 nm, zeta potential varied to −41.0 ± 2.7 mV, PDA content was 70.3 ± 5.2%, and drug release efficiency percent was 52.9 ± 2.9%. Ibudilast brain concentration was significantly (p < 0.05) higher in PDA coated micelles than oral or nasal free drug.

Nose to Brain Delivery of Transferrin conjugated PLGA nanoparticles for clonidine

The present work focuses on the development of surface modified transferrin PLGA nanoparticles loaded with clonidine for nose to brain delivery. The CLD-Tf-PLGA-NPs were developed using double emulsification, followed by solvent evaporation and characterization. Particle size, PDI and Zeta potential of the nanoparticles was 199.5 ± 1.36 nm, 0.291, −17.4 ± 6.29 mV respectively with EE% 86.2 ± 2.12 %, and DL%, 7.8 ± 0.48 %. TEM, SEM and FTIR analysis were carried out to confirm the size and transferrin coating over the surface of nanoparticles. In-vitro drug release profile were studied in PBS (pH 7.4) and SNF (pH 5.5) for 72 h and highest release was observed in PBS 89.54 ± 3.17 %. Cellular assays were conducted on Neuro-2a cells to check the cytotoxicity and uptake of Tf-modified PLGA nanoparticles and the cell viability% was obtained to be 61.85 ± 4.48 % even at maximum concentration (40Cmax) with uptake of approximately 97 %. Histopathological studies were also performed to identify the cytotoxicity on nasal epithelium along with in-vivo biodistribution and pharmacodynamics studies to assess the concentration of drug in the mice brain and behavioural responses after intranasal delivery of surface modified nanoparticles. The results showed significant increase in concentration of drug in brain and behavioural improvements in mice (p < 0.05).

Pluronic P85 decreases the delivery of phenytoin to the brain in drug-resistant rats with P-glycoprotein overexpressed chronic mesial temporal lobe epilepsy

P-glycoprotein (Pgp) overexpressed in blood brain barrier (BBB) is hypothesized to lower brain drug concentrations and thus inhibit anticonvulsant effects in drug-resistant epilepsy. Pluronic P85 (P85) was proved to enhance the delivery of drugs into the brain by inhibition of Pgp. To determine whether the surfactant P85 [versus Pgp inhibitor tariquidar (TQD)] enhance phenytoin (PHT) into the brain in drug-resistant rats with chronic mesial temporal lobe epilepsy (MTLE) induced by lithium-pilocarpine, in brain of which Pgp were overexpressed, then direct verification of PHT transport via measurement of PHT concentration in brain using microdialysis. The drug-resistant model rats were randomly divided into three groups, which were treated with PHT, 1%P85 + PHT, or PHT+TQD, respectively. 1%P85 + PHT treatment displayed a lower ratio of the area under the curve (AUC) of the PHT concentration in the brain/plasma even than that of the PHT treatment in model rats (p < 0.05), while PHT+TQD showed the highest ratio of the AUC of all treatments. However, the ratio of the PHT concentration in the liver/plasma was similar in three model groups (p > 0.05). For the ratio of the kidney/plasma, PHT+TQD treatment model group had the highest ratio of the other treatments in model rats. Thus, P85 oppositely decreased PHT concentration in brain in drug-resistant model rats with Pgp overexpressed MTLE while TQD could increase PHT distribution in brain.

Intranasal Delivery of Leuprolide Acetate Chitosan Nanoparticles for Treatment of Alzheimer’s Disease

Background: Alzheimer’s is one of the primary causes and the most prevalent form of age-related dementia worldwide. There is an urgent surge to find an effective treatment for AD due to its social implications on society. Aim: Present research work aims to develop Chitosan nanoparticles of leuprolide acetate for the treatment of Alzheimer’s disease by delivery through the intranasal route. Methods: Chitosan nanoparticles encapsulating leuprolide acetate were prepared using the ionic ge-lation method and optimized using a central composite design. The optimized nanoparticles were evaluated by DSC study, TEM analysis, release study of the drug in vitro and ex vivo, histopatholo-gy study, and accelerated stability study, In vivo kinetic and dynamic study. Results: The optimized formulation exhibited particle size of 254.3 ± 10.7 nm, % EE of 85.6 ± 0.8 %, and zeta potential of +18.0 ± 0.2 mv. The release of drug from optimized nanoparticles in vitro was in a sustained manner, with only 75.7 % drug released at 48 hours. Higher permeation of the drug from nanoparticles (Papp =5.44 ± 0.34 x 104) was observed in the diffusion study ex vivo. Sheep nasal toxicity and accelerated stability study proved the intranasal safety and stability of the developed formulation. The in vivo drug uptake study indicated a greater brain drug concentration from chitosan nanoparticles than from plain drug solution. The anti-Alzheimer potential was also evident from behavioural studies and histopathology study of rat brain. Conclusion: Thus, the chitosan nanoparticulate formulation of leuprolide acetate was found to have great potential for Alzheimer’s disease management.

Self-Assembled Lecithin-Chitosan Nanoparticles Improved Rotigotine Nose-to-Brain Delivery and Brain Targeting Efficiency

Rotigotine (RTG) is a non-ergoline dopamine agonist and an approved drug for treating Parkinson's disease. However, its clinical use is limited due to various problems, viz. poor oral bioavailability (<1%), low aqueous solubility, and extensive first-pass metabolism. In this study, rotigotine-loaded lecithin-chitosan nanoparticles (RTG-LCNP) were formulated to enhance its nose-to-brain delivery. RTG-LCNP was prepared by self-assembly of chitosan and lecithin due to ionic interactions. The optimized RTG-LCNP had an average diameter of 108 nm with 14.43 ± 2.77% drug loading. RTG-LCNP exhibited spherical morphology and good storage stability. Intranasal RTG-LCNP improved the brain availability of RTG by 7.86 fold with a 3.84-fold increase in the peak brain drug concentration (Cmax(brain)) compared to intranasal drug suspensions. Further, the intranasal RTG-LCNP significantly reduced the peak plasma drug concentration (Cmax(plasma)) compared to intranasal RTG suspensions. The direct drug transport percentage (DTP (%)) of optimized RTG-LCNP was found to be 97.3%, which shows effective direct nose-to-brain drug uptake and good targeting efficiency. In conclusion, RTG-LCNP enhanced drug brain availability, showing the potential for clinical application.

Physiologically Based Pharmacokinetic Model of Brain Delivery of Plasma Protein Bound Drugs

IntroductionA physiologically based pharmacokinetic (PBPK) model is developed that focuses on the kinetic parameters of drug association and dissociation with albumin, alpha-1 acid glycoprotein (AGP), and brain tissue proteins, as well as drug permeability at the blood–brain barrier, drug metabolism, and brain blood flow.GoalThe model evaluates the extent to which plasma protein-mediated uptake (PMU) of drugs by brain influences the concentration of free drug both within the brain capillary compartment in vivo and the brain compartment. The model also studies the effect of drug binding to brain tissue proteins on the concentration of free drug in brain.MethodsThe steady state and non-steady state PBPK models are comprised of 11–12 variables, and 18–23 parameters, respectively. Two model drugs are analyzed: propranolol, which undergoes modest PMU from the AGP-bound pool, and imipramine, which undergoes a high degree of PMU from both the albumin-bound and AGP-bound pools in plasma.ResultsThe free propranolol concentration in brain is under-estimated 2- to fourfold by in vitro measurements of free plasma propranolol, and the free imipramine concentration in brain is under-estimated by 18- to 31-fold by in vitro measurements of free imipramine in plasma. The free drug concentration in brain in vivo is independent of drug binding to brain tissue proteins.ConclusionsIn vitro measurement of free drug concentration in plasma under-estimates the free drug in brain in vivo if PMU in vivo from either the albumin and/or the AGP pools in plasma takes place at the BBB surface.

Investigation of Cannabidiol in the Mouse Drug Discrimination Paradigm.

Introduction: Cannabidiol (CBD) has gained considerable public and scientific attention because of its known and potential medicinal properties, as well as its commercial success in a wide range of products. Although CBD lacks cannabimimetic intoxicating side effects in humans and fails to substitute for cannabinoid type-1 receptor (CB1R) agonists in laboratory animal models of drug discrimination paradigm, anecdotal reports describe it as producing a "pleasant" subjective effect in humans. Thus, we speculated that this phytocannabinoid may elicit distinct subjective effects. Accordingly, we investigated whether mice would learn to discriminate CBD from vehicle. Additionally, we examined whether CBD may act as a CB1R allosteric and whether it would elevate brain endocannabinoid concentrations. Materials and Methods: C57BL/6J mice underwent discrimination training of either CBD or the high-efficacy CB1R agonist CP55,940 from vehicle. Additionally, we examined whether CBD or the CB1R-positive allosteric modulator ZCZ011 would alter the CP55,940 discriminative cue. Finally, we tested whether an acute CBD injection would elevate endocannabinoid levels in brain, and also quantified blood and brain levels of CBD. Results: Mice failed to discriminate high doses of CBD from vehicle following 124 training days, though the same subjects subsequently acquired CP55,940 discrimination. In a second group of mice trained to discriminate CP55,940, CBD neither elicited substitution nor altered response rates. A single injection of 100 or 200 mg/kg CBD did not affect brain levels of endogenous cannabinoids and related lipids and resulted in high drug concentrations in blood and whole brain at 0.5 h and continued to increase at 3 h. Discussion: CBD did not engender an interoceptive stimulus, did not disrupt performance in a food-motivated operant task, and lacked apparent effectiveness in altering brain endocannabinoid levels or modulating the pharmacological effects of a CB1R agonist. These findings support the assertions that CBD lacks abuse liability and its acute administration does not appear to play a functional role in modulating key components of the endocannabinoid system in whole animals.

Lipid and Polymeric Nanoparticles: Successful Strategies for Nose-to-Brain Drug Delivery in the Treatment of Depression and Anxiety Disorders.

Intranasal administration has gained an increasing interest for brain drug delivery since it allows direct transport through neuronal pathways, which can be quite advantageous for central nervous system disorders, such as depression and anxiety. Nanoparticles have been studied as possible alternatives to conventional formulations, with the objective of improving drug bioavailability. The present work aimed to analyze the potential of intranasal nanoparticle administration for the treatment of depression and anxiety, using the analysis of several studies already performed. From the carried-out analysis, it was concluded that the use of nanoparticles allows the drug's protection from enzymatic degradation, and the modulation of its components allows controlled drug release and enhanced drug permeation. Furthermore, the results of in vivo studies further verified these systems' potential, with the drug reaching the brain faster and leading to increased bioavailability and, consequently, therapeutic effect. Hence, in general, the intranasal administration of nanoparticles leads to a faster onset of action, with increased and prolonged brain drug concentrations and, consequently, therapeutic effects, presenting high potential as an alternative to the currently available therapies for the treatment of depression and anxiety.

Intranasal delivery of darunavir improves brain drug concentrations in mice for effective HIV treatment

Despite the availability of combined antiretroviral therapy (cART), which reduces the HIV replication in chronically HIV-infected patients, HIV associated neurocognitive disorders (HAND) persists in the brain. The blood-brain barrier (BBB) is the major barrier for the penetration of drugs including antiretrovirals, limiting the drug penetration to the brain. In the present study, we have shown improved brain drug concentration in mice for darunavir (DRV), an FDA-approved drug, using an intranasal (IN) delivery method that bypasses the BBB. Here, we compared the time-dependent biodistribution of DRV at two different concentrations, high (25 mg/kg) and low (2.5 mg/kg), using two administration routes intravenous (IV) and intranasal (IN) in brain, liver, lungs, and plasma. Compared with IV administration, IN administration demonstrated a significantly improved DRV penetration in the brain at both low and high DRV concentrations (IV vs IN: at 2.5 mg/kg: 6.91 ± 1.69 ng/g vs 12.08 ± 2.91 ng/g, at 25 mg/kg: 12.84 ± 2.88 ng/g vs 19.74 ± 1.80 ng/g). As expected, IN administration showed significantly lower DRV concentrations in plasma (IV vs IN: at 2.5 mg/kg: 81.37 ± 22.04 ng/g vs 19.91 ± 12.65 ng/g, at 25 mg/kg: 899.12 ± 136.93 ng/g vs 320.56 ± 40.04 ng/g) and liver (IV vs IN: at 2.5 mg/kg: 118.39 ± 28.13 ng/g vs 29.27 ± 4.17 ng/g at 25 mg/kg: 1085.18 ± 255.0 ng/g vs 833.83 ± 242.4 ng/g). The IN administration did not show significant change in lungs compared to the IV administration. As a result, these findings suggest that the IN route can increase the DRV level in the brain, suppressing HIV in the brain reservoirs. Additionally, it could also reduce off-target effects, especially in peripheral organs.

DDEL-13. ULTRASOUND-ENHANCED DELIVERY OF LIPOSOMAL DOXORUBICIN ACROSS THE BLOOD BRAIN BARRIER INDUCES AN IFN-GPHENOTYPE IN MICROGLIA, MACROPHAGES, AND T CELLS AND IMPROVES RESPONSE TO PD-1 BLOCKADE IN GLIOMAS

Abstract INTRODUCTION Given the limited drug penetration across the blood-brain barrier (BBB), the therapeutic potential of new and existing therapies has not been fully exploited for the benefit of glioblastoma (GBM) patients. METHODS Here we employed a novel drug delivery technology based on low-intensity pulsed ultrasound combined with intravenous microbubbles (LIPU/MB) that temporarily opens the BBB to deliver liposomal doxorubicin (DOX) and anti-PD-1 therapy (aPD-1) in mouse glioma models and 3 recurrent GBM patients. Immunological variables were evaluated in tumor and immune cells as well as efficacy in glioma-bearing mice treated with DOX delivered by LIPU. These included measurement of HLA ABC and HLA DR protein expression by tumor cells, microglia, and macrophages and IFN-g production by glioma-associated microglia and macrophages in mouse and human tumors. We also assessed efficacy of LIPU/MB enhanced combination therapy in glioma-bearing mice. RESULTS Upregulation of HLA ABC and HLA DR was observed in GBM cell lines at low concentrations of DOX. Tumor cells from GBM patients treated with DOX, aPD-1 and LIPU/MB showed increased expression of HLA ABC and HLA DR compared to paired pretreatment samples. In both mice and humans, LIPU/MB liposomal DOX increased absolute brain drug concentrations and elicited a specific IFN-g phenotype and MHC I expression in glioma-associated microglia and macrophages in mice and humans. Furthermore, LIPU/MB-mediated BBB opening increased brain concentrations of aPD-1 in mice and in peritumoral regions of GBM patients. Combined treatment with liposomal DOX and aPD-1 delivered with LIPU/MB resulted in long-term survival of glioma-bearing mice that relied on the activity of CD8+ T cells for its efficacy. CONCLUSIONS Overall, this translational study demonstrates the utility of LIPU/MB to stimulate intracranial immune responses in the context of treatment with DOX and aPD-1 for gliomas.

Design and evaluation of rufinamide nanocrystals loaded thermoresponsive nasal in situ gelling system for improved drug distribution to brain.

Rufinamide (Rufi) is an antiepileptic drug used to manage Lennox-Gastaut Syndrome and partial seizures. The oral bioavailability of Rufi is less due to its poor solubility and low dissolution rate in the gastrointestinal fluids. This results in less amount of drug reaching the brain following the oral administration of drug. Oral formulations of Rufi are prescribed at a high dose and dosing frequency to increase its distribution to the brain. A Rufi loaded thermoresponsive nasal in situ gel which showed significantly high brain concentrations compared to aqueous suspension of Rufi administered through nasal route was developed by our research group and published. In the current work, we have formulated nanocrystals of Rufi and suspended them in a xyloglucan based thermoresponsive gel to improve the nose-to-brain distribution. The particle size, polydispersity index, and yield (%) of the optimized Rufi nanocrystals were 261.2 ± 2.1 nm, 0.28 ± 0.08, and 89.6 ± 2.0 respectively. The narrow PDI indicates that the manufacturing process is reproducible and reliable. Higher % yield suggested that the method of preparation is efficient. The sol-to-gel transition of in situ gel loaded with Rufi nanocrystals was at 32°C which suggested that the formulation transforms into gel at nasal epithelial temperatures. The nasal pharmacokinetic studies showed that Rufi nanocrystals loaded in situ gel produced higher concentration of the drug in brain (higher brain Cmax) and maintained the drug concentrations for longer duration (higher mean residence time) compared to aqueous suspension of Rufi nanocrystals as well aqueous suspension of Rufi and Rufi loaded in situ gel, reported previously. Nanometric size of the Rufi nanocrystals combined with the in situ gelling properties helped the optimized formulation achieve higher brain distribution and also sustain the drug concentrations in brain for longer duration compared to any of the formulations studied by our research group.

Brain Concentrations of MDPV and its Metabolites in Male Rats: Relationship to Pharmacodynamic Effects.

MDPV (3,4-methylenedioxypyrovalerone) is a synthetic stimulant that blocks transmitter uptake at transporters for dopamine and norepinephrine. Less is known about MDPV pharmacokinetics, especially with respect to brain concentrations of the drug and its metabolites. The goal of the present study was: 1) to determine brain concentrations of MDPV and its metabolites, 3,4-dihydroxypyrovalerone (3,4-catechol-PV) and 4-hydroxy-3-methoxy-pyrovalerone (4-OH-3-MeOPV), after administration of MDPV, and 2) to relate brain pharmacokinetic measures to pharmacodynamic endpoints in the same subjects. Male Sprague-Dawley rats (300-400 g) received s.c. MDPV injection (1, 2, or 4 mg/kg) or its saline vehicle. Groups of rats were decapitated at 40 min and 240 min postinjection. Locomotor behavior was rated before decapitation, and the core temperature was obtained. Plasma and frontal cortex were analyzed to quantitate MDPV and its metabolites. Striatal samples were analyzed to measure dopamine, serotonin (5-HT), and their metabolites. MDPV displayed brain-to-plasma ratios greater than 1 (range 8.8-12.1), whereas 3,4-catechol-PV and 4-OH-3-MeO-PV showed ratios less than 1 (range 0-0.3). MDPV increased behavioural scores reflective of locomotor stimulation at 40 and 240 min and produced slight hyperthermia at 240 min. MDPV had no effect on striatal dopamine but produced an increase in the metabolite homovanillic acid (HVA). Brain MDPV concentrations were positively correlated with behavioural scores and striatal HVA but not with other endpoints. The behavioural effects of MDPV are related to brain concentrations of the parent drug and not its metabolites. The modest effects of MDPV on monoamine systems suggest that other non-monoamine mechanisms may contribute to the effects of the drug in vivo.

Vesicles of yeast cell wall-sitagliptin to alleviate neuroinflammation in Alzheimer's disease

A cell-based drug delivery system based on yeast-cell wall loaded with sitagliptin, a drug with an anti-inflammatory effect, was developed to control neuroinflammation associated with Alzheimer's disease. The optimized nanoparticles had a spherical shape with a negative surface charge, and were shown to be less toxic than the carrier and sitagliptin. Moreover, the nanoparticles caused anti-inflammatory effects against tumor necrosis factor-alpha in mice model of neuroinflammation. The pharmacokinetics study showed the brain concentration of drug in the nanoparticles group was much higher than in the control group. To evaluate the effect of P-glycoprotein on brain entry of sitagliptin, the experiment was repeated with verapamil, as a P-glycoprotein inhibitor. Brain concentration of the nanoparticles group remained approximately unchanged, proving the “Trojan Horse” effect of the developed nanocarriers. The results are promising for using yeast-cell wall as a carrier for targeted delivery to immune cells for the management of inflammation.

In Vitro-In Vivo Correlation of Blood-Brain Barrier Permeability of Drugs: A Feasibility Study Towards Development of Prediction Methods for Brain Drug Concentration in Humans.

In vitro human blood-brain barrier (BBB) models in combination with central nervous system-physiologically based pharmacokinetic (CNS-PBPK) modeling, hereafter referred to as the "BBB/PBPK" method, are expected to contribute to prediction of brain drug concentration profiles in humans. As part of our ongoing effort to develop a BBB/PBPK method, we tried to clarify the relationship of in vivo BBB permeability data to those in vitro obtained from a human immortalized cell-based tri-culture BBB model (hiBBB), which we have recently created. The hiBBB models were developed and functionally characterized as previously described. The in vitro BBB permeabilities (Pe, × 10-6cm/s) of seventeen compounds were determined by permeability assays, and in vivo BBB permeabilities (QECF) for eight drugs were estimated by CNS-PBPK modeling. The correlation of the Pe values with the QECF values was analyzed by linear regression analysis. The hiBBB models showed intercellular barrier properties and several BBB transporter functions, which were enough to provide a wide dynamic range of Pe values from 5.7 ± 0.7 (rhodamine 123) to 2580.4 ± 781.9 (rivastigmine). Furthermore, the in vitro Pe values of the eight drugs showed a good correlation (R2 = 0.96) with their in vivo QECF values estimated from human clinical data. We show that in vitro human BBB models provide clinically relevant BBB permeability that can be used as input for CNS-PBPK modeling. Therefore, our findings will encourage the development of a BBB/PBPK method as a promising approach for predicting brain drug concentration profiles in humans.