Brain Tissue Distribution Research Articles

Intranasal temperature-sensitive hydrogels of cannabidiol inclusion complex for the treatment of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a psychiatric disease that seriously affects brain function. Currently, selective serotonin reuptake inhibitors (SSRIs) are used to treat PTSD clinically but have decreased efficiency and increased side effects. In this study, nasal cannabidiol inclusion complex temperature-sensitive hydrogels (CBD TSGs) were prepared and evaluated to treat PTSD. Mice model of PTSD was established with conditional fear box. CBD TSGs could significantly improve the spontaneous behavior, exploratory spirit and alleviate tension in open field box, relieve anxiety and tension in elevated plus maze, and reduce the freezing time. Hematoxylin and eosin and c-FOS immunohistochemistry slides showed that the main injured brain areas in PTSD were the prefrontal cortex, amygdala, and hippocampus CA1. CBD TSGs could reduce the level of tumor necrosis factor-α caused by PTSD. Western blot analysis showed that CBD TSGs increased the expression of the 5-HT1A receptor. Intranasal administration of CBD TSGs was more efficient and had more obvious brain targeting effects than oral administration, as evidenced by the pharmacokinetics and brain tissue distribution of CBD TSGs. Overall, nasal CBD TSGs are safe and effective and have controlled release. There are a novel promising option for the clinical treatment of PTSD.

Development of a neural probe integrated with high-efficiency MicroLEDs for in vivo application

A neural probe with six micro-light-emitting diodes (MicroLEDs) and 15 neural electrodes was fabricated for optogenetic application. Local field potentials, which provide information about the neural activity, were successfully recorded using the neural probe, indicating the effectiveness of the neural electrodes. The MicroLEDs on the probe exhibited highly consistent current–voltage characteristics and sufficient light output of 20 mW mm−2 at 1 mA to manipulate neural activity. The light distribution in brain tissue was simulated to estimate the optical stimulation area and a number of optically stimulated neurons. The increase in LED temperature, i.e. ΔT, was investigated because high temperatures can damage brain tissue. A curve illustrating the relationship between ΔT and the wall-plug efficiency was derived. The wall-plug efficiency was increased 1.8 times by installing an Ag mirror on the back of a MicroLED. These results suggest that the MicroLED neural probe would significantly contribute to the development of neuroscience research-purposed optogenetic technology.

Madecassoside encapsulated in alginate chitosan nanoparticles exerts anti-excitotoxicity effects in pilocarpine-induced seizure

Madecassoside (MAD), a pentacyclic triterpenoid saponin, and its source herb Centella asiatica are best known for their memory enhancing and neuroprotective properties. The effects of MAD- and similar secondary metabolite-encapsulated nanoparticles on brain are least explored. Henceforth, we have developed MAD encapsulated alginate chitosan nanoparticles (MACNPs), and their therapeutic potential is studied against pilocarpine (PC) rodent seizure model. MACNPs were synthesized by ionic-gelation polyelectrolyte technique and characterized by DLS, SEM, TEM and XRD. MAD encapsulation and release profile of MACNPs were studied in vitro. MACNPs distribution in mice brain tissues was also evaluated by SEM and TEM. MACNPs offered a negative zeta potential, considerable hydrodynamic size and spherical morphology. They significantly reduced the number of animals experiencing the most severe seizures, showed enhanced bioavailability and membrane integrity. Protection of tissues by MACNPs on PC toxicity in mice was assessed by histopathology on challenged mice brain. mRNA overexpression of MAPK1, MAPK14 genes together with bcl2, caspase 3 and hspa1b for oxidative stress and inflammation was observed. However, regulated expression of mRNA in p53 gene was noted. Our results describing the anti-seizure profile, combined with its observed mRNA expression and biodistribution, strongly support MACNP as a therapeutic candidate for a diverse range of epilepsies and related stress-inflammation.

A Novel Cryptococcal Meningitis Therapy: The Combination of Amphotericin B and Posaconazole Promotes the Distribution of Amphotericin B in the Brain Tissue.

The deficient brain tissue distribution of amphotericin B (AMPB) seriously restricts its treatment for the clinical efficacy of cryptococcus neoformans meningitis (CNM). We strive to develop a tactic to increase its concentration in brain tissue. We aimed to investigate whether the combination of AMPB and posaconazole (POS) could be more effective in the treatment of CNM and to elucidate its potential mechanisms. HPLC analysis was used to analyze the concentration of AMPB in mouse serum, brain tissue, and BCECs cells. Schrodinger molecular docking, in vitro plasma balance dialysis, and ultrafiltration analysis were performed to evaluate the combinative effect of AMPB and POS with serum albumin and POS on AMPB plasma protein binding. H&E staining and colonization culture experiment of CN were employed to assess the effect of POS on the efficacy of AMPB. POS + AMPB significantly reduced the concentration of plasma total AMPB and increased its concentration in the brain tissue. However, the P-gp inhibitor zosuquidar, BCRP inhibitor Ko143, and a common inhibitor of both, elacridar, had no significant effect on its concentration. Molecular docking, balance dialysis, and ultrafiltration analysis showed that AMPB and POS had potential binding properties to serum albumin. Meanwhile, 4 and 8 μg/mL POS could significantly increase the concentration of free AMPB in plasma. POS and three inhibitors all had no significant effect on the uptake of AMPB by BCECs, but serum albumin had. The therapeutic effect of CNM in mice was confirmed that AMPB and AMPB+POS could restrain the infiltration of neutrophils and lymphocytes in cortical neurons and improve the bleeding and markedly inhibit the proliferation of CN. Collectively, we propose that POS competitively binds to the plasma protein sites of AMPB, thereby increasing its level in the brain tissue. Meanwhile, POS could enhance the efficacy of AMPB in the treatment of CNM, which may be independent of P-gp and BCRP proteins.

DDRE-14. HEMP DERIVED EXTRACELLULAR VESICLES (EVS): A POTENTIAL ANTI-GLIOMA THERAPY

Abstract INTRODUCTION Extracellular vesicles (EVs) have been harvested from many plant sources, some of which have anti-cancer effects and some could be used as therapeutic nanodelivery vectors. Hemp plant is a natural source of cannabinoids, of which delta 9-tetrahydroxicannabinol (THC) and cannabidiol (CBD) have proven anti-cancer proprieties. HYPOTHESIS We hypothesized that hemp EVs are enriched in cannabinoids and their application will reduce glioblastoma (GBM) tumor progression. APPROACH EVs were isolated from the hemp plant using ultracentrifugation. Nanotracking analysis, electron microscopy and liquid chromatography tandem mass spectrometry (LC-MS/MS) were utilized to characterize EVs. GBM cell lines were cultured in the neuropshere assay to evaluate hemp EVs anti-glioma effects. Fluorescent-labelled EVs were used to evaluate their brain tissue distribution in orthotopic patient-derived GBM xenografts. RESULTS Hemp EVs have a median diameter of 112.6nm with a typical lipid-bilayer structure. LC-MS/MS have shown that while cannabidiolic, cannabigerolic, and tetrahydroxicannabinolic acids represent 69.1 ± 2.1%, 19.1 ± 1.6%, 6.5 ± 0.54% of the total cannabinoids in hemp EVs, CBD and THC only make 4.75 ± 0.26%, and 0.5 ± 0.3%. Hemp EVs are potent anti-glioma agents with a 7-day LD-50 of 1.04µM and 2.4µM [based on EVs total cannabinoid content] for KR-158 and L0 GBM lines, respectively. Compared to the vehicle, overnight incubation of L0 cells with 1µM hemp EVs significantly reduced GBM cell migration (630.3 ± 61.43 vs 143.7 ± 8.7). Intranasal administration of hemp EVs led to a widespread distribution in tumor bearing brain including GBM tumor core. CONCLUSION Based on these results, hemp EVs with enriched cannabinoid content exert antiglioma effect in-vitro and when delivered intranasally, are widely distributed throughout the brain and within the tumor of PDX animals. Further experiments are ongoing to address the impact of nasally-delivered hemp EVs on tumor progression and compare to the application of purified acidic cannabinoids.

Feasibility studies of radioiodinated pyridyl benzofuran derivatives as potential SPECT imaging agents for prion deposits in the brain

IntroductionPrion diseases are fatal neurodegenerative disorders caused by the deposition of abnormal prion protein aggregates (PrPSc) in the central nervous system. This study aimed to evaluate the use of iodinated pyridyl benzofuran (IPBF) derivatives as single-photon emission computed tomography (SPECT) probes for the detection of cerebral PrPSc deposits. MethodsIn vitro binding assays of IPBF derivatives were carried out in the recombinant mouse prion protein (rMoPrP) and brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. SPECT imaging of 5-(5-[123I]iodobenzofuran-2-yl)-N-methylpyridin-2-amine ([123I]IPBF-NHMe) was performed on mBSE-infected and mock-infected mice. ResultsFluorescence microscopy results showed that fluorescence signals of IPBF derivatives corresponded to the thioflavin-T positive amyloid deposits of PrPSc in the brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. Among the IPBF derivatives, 5-(5-iodobenzofuran-2-yl)-N-methylpyridin-2-amine (IPBF-NHMe) exhibited the highest binding affinity to the recombinant mouse prion protein (rMoPrP) aggregates with a Ki of 14.3 nM. SPECT/computed tomography (CT) imaging and ex vivo autoradiography demonstrated that the [123I]IPBF-NHMe distribution in brain tissues of mBSE-infected mice co-localized with PrPSc deposits. Conclusion[123I]IPBF-NHMe appears to be a prospective SPECT tracer for monitoring prion deposits in living brain tissues.

Valproic acid treatment rescues injured tissues after traumatic brain injury.

No agents that are specifically neuroprotective are currently approved to emergently treat patients with traumatic brain injury (TBI). The histone deacetylase inhibitor, high-dose valproic acid (VPA) has been shown to have cytoprotective potential in models of combined TBI and hemorrhagic shock, but it has not been tested in an isolated TBI model. We hypothesized that VPA, administered after isolated TBI, will penetrate the injured brain, attenuate the lesion size, and activate prosurvival pathways. Yorkshire swine were subjected to severe TBI by cortical impact. One hour later, animals were randomized to VPA treatment (150 mg/kg delivered intravenously for 1 hour; n = 4) or control (saline vehicle; n = 4) groups. Seven hours after injury, animals were sacrificed, and brain lesion size was measured. Mass spectrometry imaging was used to visualize and quantitate brain tissue distribution of VPA. Sequential serum samples were assayed for key biomarkers and subjected to proteomic and pathway analysis. Brain lesion size was 50% smaller (p = 0.01) in the VPA-treated animals (3,837 ± 948 mm) compared with the controls (1,900 ± 614 mm). Endothelial regions had eightfold higher VPA concentrations than perivascular regions by mass spectrometry imaging, and it readily penetrated the injured brain tissues. Serum glial fibrillary acid protein was significantly lower in the VPA-treated compared with the control animals (p < 0.05). More than 500 proteins were differentially expressed in the brain, and pathway analysis revealed that VPA affected critical modulators of TBI response including calcium signaling pathways, mitochondria metabolism, and biosynthetic machinery. Valproic acid penetrates injured brain tissues and exerts neuroprotective and prosurvival effects that resulted in a significant reduction in brain lesion size after isolated TBI. Levels of serum biomarkers reflect these changes, which could be useful for monitoring the response of TBI patients during clinical studies.

Preparation of a novel ginkgolide B niosomal composite drug

AbstractGinkgolide B (GB) and Puerarin (Pue) are active pharmaceutical ingredients for the treatment of Parkinson’s disease (PD); however, both are poorly water-soluble, which limits their bioavailability. The present study used the niosome vesicle encapsulation technique to prepare a novel GB composite drug. The conditions for GB–Pue niosomal complex preparation were as follows: a hydration temperature of 60°C, a hydrophilic–lipophilic balance of 10.5, a drug–carrier mass ratio of 8:100, and a surfactant–cholesterol mass ratio of 1.5:1. The niosomal complex suspension was uniformly distributed and milky white in color, with no stratification over a duration of 1 month. It had an average particle size of 187.3 nm, a particle-size distribution of 0.237, a GB encapsulation efficiency (EE) of 68.2%, a GB drug-loading rate of 90.1%, a Pue EE of 40.5%, and a Pue drug-loading rate of 83.3%. The optimal storage temperature for the niosomal complex suspension was 4°C. Following an intravenous injection of the niosomal complex suspension into the rat tail, the area under the curve (AUC) from 0 to 4 h was 54.1 h µg mL−1, with a mean residence time (MRT) of 0.96 h, a distribution half-life (T1/2α) of 0.195 h, and a total clearance of 0.003 L h−1 kg−1. The AUC and MRT of the composite prescription were 1.1- and 1.4-times those of the commercial injection, respectively, showing significantly increased sustained release and bioavailability. Moreover, the distribution of GB in the brain tissue was 1.8-times that of the commercial injection. In conclusion, the novel GB niosomal composite drug, with excellent stability, improved pharmacokinetics, and brain tissue distribution, demonstrates great potential for the delivery of GB and Pue for PD therapeutics.

&lt;p&gt;Transferrin-Modified Osthole PEGylated Liposomes Travel the Blood-Brain Barrier and Mitigate Alzheimer’s Disease-Related Pathology in APP/PS-1 Mice&lt;/p&gt;

IntroductionOsthole (Ost) is a coumarin compound that strengthens hippocampal neurons and neural stem cells against Aβ oligomer-induced neurotoxicity in mice, and is a potential drug for the treatment of Alzheimer's disease (AD). However, the effectiveness of the drug is limited by its solubility and bioavailability, as well as by the low permeability of the blood-brain barrier (BBB). In this study, a kind of transferrin-modified Ost liposomes (Tf-Ost-Lip) was constructed, which could improve the bioavailability and enhance brain targeting.MethodsTf-Ost-Lip was prepared by thin-film hydration method. The ability of liposomal formulations to translocate across BBB was investigated using in vitro BBB model. And the protective effect of Tf-Ost-Lip was evaluated in APP-SH-SY5Y cells. In addition, we performed pharmacokinetics study and brain tissue distribution analysis of liposomal formulations in vivo. We also observed the neuroprotective effect of the varying formulations in APP/PS-1 mice.ResultsIn vitro studies reveal that Tf-Ost-Lip could increase the intracellular uptake of hCMEC/D3 cells and APP-SH-SY5Y cells, and increase the drug concentration across the BBB. Additionally, Tf-Ost-Lip was found to exert a protective effect on APP-SH-SY5Y cells. In vivo studies of pharmacokinetics and the Ost distribution in brain tissue indicate that Tf-Ost-Lip prolonged the cycle time in mice and increased the accumulation of Ost in the brain. Furthermore, Tf-Ost-Lip was also found to enhance the effect of Ost on the alleviation of Alzheimer’s disease-related pathology.ConclusionTransferrin-modified liposomes for delivery of Ost has great potential for AD treatment.

Radiolabeling of [11C]FPS-ZM1, a receptor for advanced glycation end products-targeting positron emission tomography radiotracer, using a [11C]CO2-to-[11C]CO chemical conversion.

Aim: The receptor for advanced glycation end products (RAGE) is a viable target for early Alzheimer's disease (AD) diagnosis using positron emission tomography (PET) as RAGE overexpression precedes Aβ plaque formation. The development of a carbon-11 analog of FPS-ZM1 (N-benzyl-4-chloro-N-cyclohexylbenzamide, [11C]FPS-ZM1), possessing nanomolar affinity for RAGE, may enable the imaging of RAGE for early AD detection. Methodology & results: Herein we report an optimized [11C]CO2-to-[11C]CO chemical conversion for the synthesis of [11C]FPS-ZM1 and in vitro brain autoradiography. The [11C]CO2-to-[11C]CO conversion via 11C-silanecarboxylate derivatives was achieved with a 57% yield within 30sfrom end of [11C]CO2 delivery. [11C]FPS-ZM1 was obtained with a decay-corrected isolated radiochemical yield of 9.5%. Conclusion: [11C]FPS-ZM1 distribution in brain tissues of wild-type versus transgenic AD model mice showed no statistically significant difference and high nondisplaceable binding.

Mass Spectrometry-Based Rapid Quantitative Bioanalysis of Flibanserin: Pharmacokinetic and Brain Tissue Distribution Study in Female Rats.

Flibanserin (FLB) is the first United States Food and Drug Administration (USFDA) approved serotonin modulator recently marketed to treat acquired generalized women hypoactive sexual desire disorder. The scope of this study was to develop and validate a sensitive, selective and reliable ultra-performance liquid chromatography-mass spectroscopy/mass spectroscopy-based quantification method for FLB in rat plasma as well as brain tissue samples. The method includes a simple liquid-liquid sample extraction procedure. FLB was subjected to chromatographic separation using a poroshell C18 column with the mobile phase comprising a mixture of acetonitrile (ACN), 10mM ammonium acetate and acetic acid (90:10:0.1, v/v/v). Detection and quantification of FLB after positive electrospray ionization were carried out in selective ion monitoring mode. The fragment ions (m/z) of FLB (parent ion: 391.1741) and IS (parent ion: 448.1550) were monitored at 161.0704 and 285.0917, respectively. A linear response of FLB was observed over a concentration range of 2.5-600ng/mL in plasma and 5-500ng/mL in brain tissue homogenate. The intra- and inter-day precision and accuracy of the method met the acceptable limits specified in the USFDA bioanalytical method validation guideline. The analyte was found to be stable in benchtop, freeze-thaw, auto-injector and dry extract stability studies. The developed method was used to quantitate FLB in the plasma and brain tissue of a single-dose oral pharmacokinetic and brain tissue distribution study in female rats. Maximum FLB concentration in plasma and brain was achieved within an hour; however, the total amount of the drug that reached the brain was significantly less than in plasma. Rate of elimination of FLB from brain was also faster resulting in a lesser half-life in brain compared to the plasma.

UPLC-MS/MS determination of active components from Wuzhuyu Decoction in plasma and brain tissues of nitroglycerin-induced migraine rats

A sensitive and specific ultra-performance liquid chromatography-mass spectrometry(UPLC-MS/MS) method was deve-loped for analysis of rutaecarpine(Ru), evodiamine(Ev), rutaevine(Rv), limonin(Li), ginsendside Rb_1(Rb_1), ginsendside Re(Re) in rat plasma and brain tissues of nitroglycerin-induced migraine rats. Male healthy Sprague-Dawley(SD) rats were orally given multiple dose of optimized(OS) and un-optimized Wuzhuyu Decoction(UNOS), and their blood samples and brainstem were collected at different time points after injection of nitroglycerin(10 mg·kg~(-1)) into the frontal region. The drug concentrations of the 6 analytes in plasma and brainstem were determined by UPLC-MS/MS method. Subsequently, the main pharmacokinetics parameters of plasma were calculated by using Phoenix WinNolin 5.2.1 software. The methodological test showed that all of analytes in both plasma and brainstem homogenate exhibited a good linearity within the concentration range(r&gt;0.994 7). The intra-day and inter-day accuracy, precision, matrix effect, stability of the investigated components meet the requirements for biopharmaceutical analysis. The developed method was successfully applied in pharmacokinetic studies on abovementioned ingredients in rat plasma and brain stem. The plasma pharmacokinetic parameters of active ingredients in two different Wuzhuyu Decoction group were compared, it was found that Rb_1 had higher t_(1/2), T_(max), C_(max), AUC_(0-24 h) and AUC_(0-∞ )in OS group. Meanwhile, Ev had higher t_(1/2) and T_(max) but lower C_(max), AUC_(0-24 h) and AUC_(0-∞), Ru has higher t_(1/2 )but lower C_(max), AUC_(0-24 h) and AUC_(0-∞ )in OS group. The brain tissue distribution of each component were compared between the two groups, the component with higher content in OS, such as Ru at 30 min and 2 h after administration, Ev at 30 min, Rb_1 at 30 min and Rb_1 at 2 h after administration have lower brain tissue distribution than those in UNOS group, while the component with higher content in UNOS, such as Rv at 30 min, 2 h and 12 h after administration had higher brain tissue distribution than those in OS group.

Efficient radiosynthesis and preclinical evaluation of [18 F]FOMPyD as a positron emission tomography tracer candidate for TrkB/C receptor imaging.

Herein we report an efficient radiolabeling of a 18 F-fluorinated derivative of dual inhibitor GW2580, with its subsequent evaluation as a positron emission tomography (PET) tracer candidate for imaging of two neuroreceptor targets implicated in the pathophysiology of neurodegeneration: tropomyosin receptor kinases (TrkB/C) and colony stimulating factor receptor (CSF-1R). [18 F]FOMPyD was synthesized from a boronic acid pinacolate precursor via copper-mediated 18 F-fluorination concerted with thermal deprotection of the four Boc groups on a diaminopyrimidine moiety in an 8.7±2.8% radiochemical yield, a radiochemical purity >99%, and an effective molar activity of 187±93 GBq/μmol. [18 F]FOMPyD showed moderate brain permeability in wild-type rats (SUVmax = 0.75) and a slow washout rate. The brain uptake was partially reduced (ΔAUC40-90 = 11.6%) by administration of the nonradioactive FOMPyD (up to 30 μg/kg). In autoradiography, [18 F]FOMPyD exhibits ubiquitous distribution in rat and human brain tissues with relatively high nonspecific binding revealed by self-blocking experiment. The binding was blocked by TrkB/C inhibitors, but not with a CSF-1R inhibitor, suggesting selective binding to the former receptor. Although an unfavorable pharmacokinetic profile will likely preclude application of [18 F]FOMPyD as a PET tracer for brain imaging, the concomitant one-pot copper-mediated 18 F-fluorination/Boc-deprotection is a practical technique for the automated radiosynthesis of acid-sensitive PET tracers.

Preparation, preliminary pharmacokinetics and brain tissue distribution of Tanshinone IIA and Tetramethylpyrazine composite nanoemulsions

Objective: Tanshinone IIA (TSN) and Tetramethylpyrazine (TMP) were combined in a composite, oil-in-water nanoemulsions (TSN/TMP O/W NEs) was prepared to prolong in vitro and vivo circulation time, and enhance the bioavailability of TSN.Material and methods: Physicochemical characterization of TSN/TMP O/W NEs was characterized systematically. The in vitro dissolution and in vivo pharmacokinetic experiments of TSN/TMP O/W NEs were also evaluated.Result: A formulation was optimized, yielding a 32.5 nm average particle size, an encapsulation efficiency of over 95 %, and were spherical in shape as shown by TEM. TSN/TMP O/W NEs were shown to extend the release and availability in vitro compared to raw compounds. In pharmacokinetic study, the AUC0→∞ and t1/2 of the TSN/TMP O/W NEs were 481.50 mg/L*min and 346.39 min higher than TSN solution, respectively. Brain tissue concentration of TSN was enhanced with TSN/TMP O/W NEs over raw TSN and even TSN O/W NEs.Conclusions: Therefore, nanoemulsions are an effective carrier to increase encapsulation efficiency of drugs, improve bioavailability and brain penetration for TSN – which is further enhanced by pairing with the co-delivery of TMP, providing a promising drug delivery.

Interferometric optical testing to discriminate benign and malignant brain tumors

When normal cells suffer from the malignant disease, changes occur in cellular size and structure, and their constituents. These changes can affect the biological response of cells and tissues. Conventional hematoxylin and eosin staining, which is the gold standard of tumor diagnosis provide a very detailed view of the tissue by staining cell structures to diagnose a disease based on the deformation of the cells. However, this study shows changes in cells and tissues structure due to malignant diseases can also affect the optical properties. The purpose of this research was to assess and compare these effects to identify benign and malignant brain tissues from each other. Various samples of adult human brain tissues were studied using Mach–Zehnder interferometer as an optical method and using the Fourier transform method as an analytical process. The formed interference patterns of benign and malignant brain tumors were investigated to obtain the phase distribution of tumors. The obtained information demonstrated that the phase distribution of malignant brain tissues was different from benign brain tissues. The phase distribution approximately ranged from 10 to 120 rad for benign samples and from 10 to 160 rad for malignant samples. Moreover, the average of unwrapped phase distribution was 63.79 and 85.69 rad in benign and malignant samples, respectively. This results indicated that the proposed laser-based technique, Mach–Zehnder interferometer method, can be used as an auxiliary procedure along with histological techniques to identify benign and malignant brain tumors from each other. It is suggested that the unwrapped phase distribution of tissues be considered as an optical property for differentiating various brain tumors.

Superiority of TPGS-loaded micelles in the brain delivery of vinpocetine via administration of thermosensitive intranasal gel.

Background: Vinpocetine (VPN) is a synthetic derivative of the Vinca minor alkaloids. The drug is characterized by a short half-life, limited water solubility and high hepatic first-pass effect. The objective was to develop different lipid-based nanocarriers (NCs) loaded into a thermosensitive in situ gelling (ISG) system to improve VPN bioavailability and brain targeting via intranasal (IN) delivery.Methods: Different lipid-based NCs were developed and characterized for vesicle size, zeta potential, VPN entrapment efficiency (EE) and morphological characterization using transmission electron microscope (TEM). The prepared NCs were loaded into ISG formulations and characterized for their mucoadhesive properties. Ex-vivo permeation and histological study of the nasal mucosa were conducted. Pharmacokinetic and brain tissue distribution were investigated and compared to a marketed VPN product following administration of a single dose to rats.Results: VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets. VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets.Conclusion: VPN-loaded TPGS-micelles ISG formulation is a successful brain drug delivery system with enhanced bioavailability for drugs with poor bioavailability and those that are frequently administered.

Effect of N-acetyl-L-cysteine on bioavailability and brain distribution of curcumin by nasal delivery

Curcumin( Cur) is a natural active substance extracted from the roots or tubers of traditional Chinese medicinal materials. It has anti-inflammatory and anti-tumor activities on brain diseases. Due to the poor stability,low solubility,poor absorption and low bioavailability of curcumin,N-acetyl-L-cysteine( NAC) was used as an absorption enhancer and mixed with curcumin to improve the absorption of curcumin in the body. In this paper,curcumin was smashed by airflow pulverization,and Cur-NAC mixtures were prepared by being grinded with liquid. Then,the raw material and the product were analyzed by differential scanning calorimetry( DSC),X-ray diffraction( XRD) for structural characterization. The dissolution was determined by high performance liquid chromatography( HPLC) analysis. The characteristic peaks of the samples prepared by grinding method were similar to those of the raw materials,while the melting temperature and the accumulated dissolution degree were not significantly changed. The crystal forms of the products were not changed,and no new crystal form was formed after grinding. After the administration of intranasal powder,blood samples were collected from the orbit,while the whole brain tissues were removed from the skull and dissected into 10 anatomical regions. The concentrations of curcumin in these samples were determined by UPLC-MS/MS. The concentrations of curcumin in plasma and brain were compared at different time points. After intranasal administration of two drugs,it was found that the concentration of curcumin after sniffing up the mixtures in plasma was high,and the concentration of the drug in the olfactory bulb,hippocampus,and pons was increased significantly. Within 0. 083-0. 5 h,the olfactory bulb,piriform lobe and hippocampus remained high concentrations,the endodermis,striatum,hypothalamus and midbrain reached high concentrations within 1-3 h; and the cerebellum,pons and brain extension maintained relatively high concentrations within 3-7 h. The experiment showed that nasal administration of Cur-NAC mixtures can significantly improve the bioavailability of curcumin,and lead to significant differences in brain tissue distribution.

The Optimization and Production of Ginkgolide B Lipid Microemulsion

AbstractIn this study, we introduce a method to formulate Ginkgolide B lipid microemulsion (GB-LM). We have assessed its general characteristics and pharmacokinetics in animals. Soybean oil (10.0%) and oleic acid (2.4%) were chosen as the oil phase, refined egg yolk lecithin (PC98T) (1.8%) as the surfactant, and glycerol (2.25%) as the co-surfactant. The optimized formulation process resulted in particles with average diameter of 185.9 ± 52.5 nm and the zeta potential of −19.8 ± 1.3 mV. The GB-LM remained steady for three months at room temperature. Giving each dose of 4 mg/kg to rats through the vein, a clearance rate of CL (L/h): 2.594 and C max (ng/mL) was achieved: 353.8 through pharmacokinetic analysis and statistical analysis. The AUC of GB-LM was about 1.57-fold higher than that of the products available in the market. In addition, brain tissue distribution studies show that after 0.5 h administration of GB, the concentration of GB in brain tissue can reach its maximum, and then significantly decrease after 2 hours. Therefore, the improved formulation of GB-LM shows encouraging results compared with present products in several features.

Pharmacokinetic Studies of Three Alkaloids in Rats After Intragastrical Administration of Lycopodii Herba Extract by LC-MS/MS.

Lycopodii Herba is a widely used traditional medicinal herb, and contains diverse fascinating alkaloids. In this study, a fast and sensitive LC-MS/MS method for the simultaneous determination of lycodoline, α-obscurine, and N-demethyl-α-obscurine from Lycopodii Herba in rat plasma and brain tissue was developed and validated. Biological samples were extracted via a protein precipitation procedure using methanol as the extraction solvent and Huperzine B as the internal standard. Chromatographic separation was carried out using a Thermo Syncronis-C18 column (50 mm × 2.1 mm, 5 μm) and a gradient mobile phase containing methanol and water with 0.05% formic acid. The three alkaloids were detected by positive electrospray ionization in selective reaction monitoring mode. The selectivity, crosstalk, carryover effect, linearity, accuracy, precision, extraction recovery, matrix effect, and stability of the current method were validated. Then, using the validated method, the plasma pharmacokinetics and brain tissue distribution of the alkaloids in rats were investigated after intragastrical administration of Lycopodii Herba extract. The three alkaloids were shown to be rapidly absorbed into the blood (Tmax, 0.79–1.58 h), and then also eliminated rapidly (t1/2, 1.27–2.24 h). All of them could pass through the blood–brain barrier. The method provides a new research approach to expand preclinical studies of Lycopodii Herba.

Alzheimer\u2019s disease phospholipase C-gamma-2 (PLCG2) protective variant is a functional hypermorph

BackgroundRecent Genome Wide Association Studies (GWAS) have identified novel rare coding variants in immune genes associated with late onset Alzheimer’s disease (LOAD). Amongst these, a polymorphism in phospholipase C-gamma 2 (PLCG2) P522R has been reported to be protective against LOAD.PLC enzymes are key elements in signal transmission networks and are potentially druggable targets. PLCG2 is highly expressed in the hematopoietic system. Hypermorphic mutations in PLCG2 in humans have been reported to cause autoinflammation and immune disorders, suggesting a key role for this enzyme in the regulation of immune cell function.MethodsWe assessed PLCG2 distribution in human and mouse brain tissue via immunohistochemistry and in situ hybridization. We transfected heterologous cell systems (COS7 and HEK293T cells) to determine the effect of the P522R AD-associated variant on enzymatic function using various orthogonal assays, including a radioactive assay, IP-One ELISA, and calcium assays.ResultsPLCG2 expression is restricted primarily to microglia and granule cells of the dentate gyrus. Plcg2 mRNA is maintained in plaque-associated microglia in the cerebral tissue of an AD mouse model. Functional analysis of the p.P522R variant demonstrated a small hypermorphic effect of the mutation on enzyme function.ConclusionsThe PLCG2 P522R variant is protective against AD. We show that PLCG2 is expressed in brain microglia, and the p.P522R polymorphism weakly increases enzyme function. These data suggest that activation of PLCγ2 and not inhibition could be therapeutically beneficial in AD. PLCγ2 is therefore a potential target for modulating microglia function in AD, and a small molecule drug that weakly activates PLCγ2 may be one potential therapeutic approach.