AmyloLipid Nanovesicles: A self-assembled lipid-modified starch hybrid system constructed for direct nose-to-brain delivery of curcumin

AmyloLipid nanovesicles (ALNs) are new lipid-modified starch complex nanoparticles developed and presented as nanocarriers of curcumin for targeting the CNS via the intranasal route. Curcumin has been indicated as a promising active agent with a variety of pharmacological activities, including a potential ability to treat brain tumors, traumatic brain injury, and CNS disorders, such as Alzheimer's disease, as it may inhibit amyloid-β-protein (Aβ) aggregation and Aβ-induced inflammation. Although curcumin has a tremendous potential as a therapeutic agent for CNS disorders, its low bioavailability and its rapid total body clearance reduce any chance for therapeutic levels to reach the brain. By using an optimized (2% crosslinked starch) curcumin-loaded ALNs, which was fabricated from a microemulsion as a precursor, an average of 141.5 ± 55.9 ng/g brain levels and 11.9 ± 12.0 ng/ml plasma concentrations were detected, one hour following intranasal administration of 160 μg/kg dose of curcumin. In comparison, 1 h after IV administration of the same dose, no CUR was detected in the brain and the mean plasma level was approximately one half of the level monitored after intranasal ALNs, i.e., 7.25 ± 0.20 ng/ml. It has been clearly demonstrated, therefore, that a well-designed ALN formulation proved itself as a promising carrier for intranasal delivery and brain targeting of curcumin.

Impact of rasagiline nanoparticles on brain targeting efficiency via gellan gum based transdermal patch: A nanotheranostic perspective for Parkinsonism

Rasagiline mesylate is used as first line agent for early management of Parkinson's disease but its water soluble nature creates hurdles to cross blood brain barrier also its low oral bioavailability and rapid elimination requires frequent dosing. Thus present study aims to prepare rasagiline mesylate-nanoparticles (RM-NPs) loaded gellan gum transdermal film for non-invasive; self-administration in elderly patients. PLGA coated RM-NPs prepared by solvent evaporation technique were incorporated into film prepared by solvent casting method. Optimized films with 1.127 g gellan gum and 1.962 % linoleic acid showed enhanced ex-vivo diffusion over a period of 72 h. Comparative pharmacokinetic study revealed increased bioavailability of rasagiline on transdermal application compared to oral route. In-vivo anti-Parkinson activity estimated by behavioural and biochemical analysis indicate reserpine to interfere with monoamine storage hence resulting in development of akinesia and PD-like symptoms in rats. Brain targeting monitored by gamma imaging showed effective brain drug uptake from transdermal film which was also supported by increased brain targeting efficiency estimated from biodistribution study. Thus, the data support efficacy of gellan gum film to target drug to brain region compared to oral route and hence can be employed as a convenient approach for long-term treatment of Parkinson's disease in elderly patients.

Neurotherapeutic applications of nanomedicine for treating Alzheimer's disease

Alzheimer's disease (AD) is a progressive, irreversible, fatal brain disease which disturbs cognitive functions. It affects 35 million people worldwide and the number of people suffering may increase to 100 million by 2050 if no effective treatments are available. The present treatment improves cognitive functions and provide temporary symptomatic relief, but do not stop or delay the disease progression. Moreover, they are mainly available as conventional oral dosage forms and these conventional oral medications lack brain specificity and also produce side effects which leads to poor patient compliance. Brain drug targeting by nanomedicines is a promising approach to improve brain targeting specificity, brain bioavailability and patient compliance. The present review discuses about the currently available pharmacotherapy for AD and the neurotherapeutic applications as well as the advancements of nanomedicine for treating AD. It also highlights the recent advancements of various nanomedicines containing phytopharmaceuticals for treating AD. It is believed that nanomedicines containing approved drugs can be transformed into the clinics hence improve the life style of AD patients.

Brain uptake and accumulation of new levofloxacin-doxycycline combination through the use of solid lipid nanoparticles: Formulation; Optimization and in-vivo evaluation

The objective of this study is to investigate the feasibility of delivery of novel levofloxacin/ doxycycline (LEVO/DOX) combination to the brain by intranasal route to achieve a significant local concentration in the brain and a direct nose-to-brain pathway. Solid lipid nanoparticles (SLN) were selected as a drug carrier and employed Box-Behnken design for optimizing LEVO/DOX-SLN to achieve minimum particle size and maximum apparent entrapment efficiency (EE). SLNs were prepared by hot emulsification and characterized. In vitro release of optimized formulations showed prolonged drug release from the optimized formulation. The results of pharmacokinetic study of the optimized SLN-HPMC gel in plasma and brain revealed significant increase in the brain peak concentration (420, 315 ng/g), the AUC _0-360 min (57130 and 48693.13 ng. min/g) in comparison to intranasal LEVO/DOX free solution with the values of (160, 120) ng/g, (36850, 27637.5 ng⋅min/g) for LEVO and DOX, respectively. The optimized LD-SLN-HPMC gel gave a drug-targeting efficiency (DTE %) of 149.815 and 161.969 for LEVO and DOX, respectively, in comparison to the intravenous route. Moreover, the optimized formulation had a direct transport percentage (DTP %) of 33.285 and 40.236 for LEVO and DOX, respectively, which indicates a significant contribution of direct nose-to-brain pathway in brain drug delivery.

Intranasal tetrandrine temperature-sensitive in situ hydrogels for the treatment of microwave-induced brain injury

The brain is the most sensitive organ to microwave radiation. However, few effective drugs are available for the treatment of microwave-induced brain injury due to the poor drug permeation into the brain. Here, intranasal tetrandrine (TET) temperature-sensitive in situ hydrogels (ISGs) were prepared with poloxamers 407 and 188. Its characteristics were evaluated, including rheological properties, drug release in vitro, and mucosal irritation. The pharmacodynamics and brain-targeting effects were also studied. The highly viscous ISGs remained in the nasal cavity for a long time with the sustained release of TET and no obvious ciliary toxicity. Intranasal temperature-sensitive TET ISGs markedly improved the spatial memory and spontaneous exploratory behavior induced by microwave with the Morris water maze (MWM) and the open field test (OFT) compared to the model. The ISGs alleviated the microwave-induced brain damage and inhibited the certain mRNA expressions of calcium channels in the brain. Intranasal temperature-sensitive TET ISGs was rapidly absorbed with a shorter T_max (4.8 h) compared to that of oral TET (8.4 h). The brain targeting index of intranasal temperature-sensitive TET ISGs was as 2.26 times as that of the oral TET. Intranasal temperature-sensitive TET ISGs are a promising brain-targeted medication for the treatment of microwave-induced brain injury.

Nasal timosaponin BII dually sensitive in situ hydrogels for the prevention of Alzheimer's disease induced by lipopolysaccharides

Alzheimer's disease (AD) is a common and severe brain disease with a high mortality among the elders, but no highly efficient medications are currently available. For example, timosaponin BII, an efficient anti-AD agent, has low oral bioavailability. Here, timosaponin BII was formulated in a temperature/ion-sensitive in situ hydrogel (ISG) that was well transformed into gels in the nasal environment. Timosaponin BII protected the PC12 cells injured by lipopolysaccharides (LPS) by decreasing TNF-α and IL-1β and stabilizing F-actin. Timosaponin BII ISGs were intranasally administered to the mice every day for 38 days. On Day 36, LPS was injected to the mice to establish an AD model. Morris water maze experiments showed that the number of the animals that were able to cross the platform returned to normal and the total distance over which the animals moved in the open field also increased, which demonstrated that the spatial memory and spontaneous behavior were improved after treatment compared to the model. Moreover, an AD improver, inducible nitric oxide synthase (iNOS) in the brain, was reduced after treatment. High brain targeting effect of timosaponin BII ISGs was confirmed by in vivo fluorescence imaging. The nasal timosaponin BII dually sensitive ISGs can serve as a promising medication for local prevention of AD.

Nanoemulsions for targeting the neurodegenerative diseases: Alzheimer's, Parkinson's and Prion's

Neurodegenerative diseases need the drugs to be delivered right inside the brain to maximizing the therapeutic effects. This can be achieved by use of novel targeted delivery systems such as nanoemulsions. Nanoemulsions (NE) are nano-sized emulsions that are manufactured for enhancing the delivery of drugs to the targeted site and minimize adverse effects and toxic reactions. Looking into the advanced pharmaceutical applications of NE, the present review gives an insight to the understanding of the application of NE in NDs like AD, PD and Prion's disease. The review also touches upon the pathophysiology of these ND diseases to have a clear understanding of the molecular aspects of the disease. Finally, the review sets a standpoint of nanoemulsion's significance in the treatment therapy of ND besides the drawbacks associated with the current drug therapy in NDs.

Facile nose-to-brain delivery of rotigotine-loaded polymer micelles thermosensitive hydrogels: In vitro characterization and in vivo behavior study

A rotigotine (ROT)-loaded polymer micelles thermosensitive gel (ROT-PM-TSG) delivery system was engineered to enhance the solubility of the drug, prolong the residence time, and increase the concentration of the drug in the brain tissue. First, ROT-loaded polymer micelles (ROT-PM) were tailored and optimized. The average particle size, encapsulation efficiency, and drug loading of the ROT-PM were (88.62 ± 1.47) nm, (93.5 ± 0.79) %, and (19.9 ± 0.60) %. The optimal ROT-PM-TSG formulation contained 22% P407 and 2% P188 with a gelation temperature of about 32.3 °C and a pH of 5.186. In vivo, the MRT of ROT-PM and ROT-PM-TSG nasal administration was 1.43 and 1.79 times extended than that of the intravenous. In comparison with the intravenous group, the distribution of ROT in olfactory bulb, cerebrum, cerebellum and striatum was 276.6%, 170.5%, 166.5% and 184.4%, respectively. In conclusion, the ROT-PM-TSG system has proven to be a potential application prospect as a ROT nose-to-brain delivery system.

PEGylated nanocarriers: A promising tool for targeted delivery to the brain

Targeted drug delivery across the blood-brain barrier is an extremely challenging quest in the fight with fatal brain ailments, with the major hurdles being short circulation time, reticuloendothelial system (RES) uptake, and excretion of nanocarriers. PEGylation has emerged as a boon for targeted drug delivery to the brain. It is well established that PEGylation can increase the circulation time of nanocarriers by avoiding RES uptake, which is indispensable for increasing the brain's uptake of nanocarriers. PEGylation also acts as a linker for ligand molecules to achieve active targeting to the brain. Using PEGylation, novel approaches are being investigated to facilitate ligand-receptor interactions at the brain endothelium to ease the entry of therapeutic drugs into the brain. In addition, PEGylation made it simpler to assess the brain tissue for delivering diagnostic molecules and theranostic nanocarriers. The potential of PEGylated nanocarriers is being investigated vastly to boost the therapeutic effect several fold in the treatment of brain diseases. This review sheds light on the contribution of PEGylated nanocarriers, especially liposomes, polymeric nanoparticles, and dendrimers for brain-specific delivery of bioactives.

Brain targeting stealth lipomers of combined antiepileptic-anti-inflammatory drugs as alternative therapy for conventional anti-Parkinson's

This study presents an alternative therapy to conventional anti-Parkinson's treatment strategies; where motor and non-motor symptomatic complications are considered. Thus; providing sustainability, patient compliance, therapeutic safety and efficiency, based on triggering secretion of endogenous dopamine (DA). Exogenous DA has long been considered the best therapy, however, its poor blood brain barrier (BBB) permeability, fluctuated plasma levels, and non-motor complications negligence, decreased response to therapy with time. Consequently; brain targeting Tween®80-coated pegylated lipomers were tailored for intravenous administration (IV) of L-Dopa, and two drugs of reported neuroprotective effect: lamotrigine (LTG) and tenoxicam (TX). Single-step nanoprecipitation method was used; for its reproducibility and ease of scaling-up. Formulation targeting and anti-PD efficiency was evaluated against marketed standards and L-Dopa. In-vitro and in-vivo pharmacokinetic and dynamic studies were carried out for setting optimization standards upon varying inter-components ratio. Results revealed that lipomers are, generally, significantly efficient in brain targeting compared to oral tablets. LTG-lipomers (LF20) showed the maximum anti-PD compared to its TX and L-Dopa analogues. Combining LTG and TX had synergistic effect; highlighting a new prescription for both drugs. Thus; offering a safe, targeted, and therapeutically efficient sustained dosage form, capable of mitigating PD risk and treating it though weekly administration. Hence; presenting a novel promising anti-neurodegenerative strategy; on employing various mechanisms that were previously achieved through additional therapeutic supplements.

Borneol and poly (ethylene glycol) dual modified BSA nanoparticles as an itraconazole vehicle for brain targeting

Itraconazole (ITZ) can be used for the treatment of cryptococcus neoformans meningitis and aspergillus brain abscess. While, the inherent hydrophobicity of ITZ and the existence of blood brain barrier (BBB) limit its applications as a central nervous system drug. In this study, a novel brain targeting drug delivery system based on bovine serum albumin (BSA) was constructed for enhancing ITZ distribution in brain. Firstly, ITZ was loaded into BSA nanoparticles (ITZ-NPs) with 11.6% of drug loading. Subsequently, the nanoparticles were modified with borneol (BO) and polyethylene glycol (PEG) (PEG/BO-ITZ-NPs). The resulting nanoparticles retained their nanosize (186.3 nm), uniform and spherical morphology, and negative surface charge (-21.03 mV). Cell uptake studies showed that compared with ITZ-NPs, PEG/BO-ITZ-NPs had significantly increased uptake in bEnd.3 cells, and the increase in BO concentration was beneficial for the cellular uptake of NPs. Moreover, PEG/BO-ITZ-NPs displayed an approximately 3.5-fold higher area under the curve in rats and about 2-fold higher brain distribution in mice than that of Sporanox®, i.e. ITZ solubilized by hydroxylpropyl-β-cyclodetrin, after i.v. administration. In a word, BO and PEG dual modified BSA nanoparticles may potentially serve as an ITZ vehicle for brain targeting.

Intranasal delivery of paeoniflorin nanocrystals for brain targeting

Paeoniflorin (PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation (PA-NCs) that is suitable for intranasal administration to treat Parkinson's disease (PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of −23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%, which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells. Moreover, PA-NCs conferred desirable protective effect against MPP⁺-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PA-NCs is a promising treatment strategy for PD.

Menthol-modified casein nanoparticles loading 10-hydroxycamptothecin for glioma targeting therapy

Chemotherapy outcomes for the treatment of glioma remains unsatisfactory due to the inefficient drug transport across the blood-brain barrier (BBB) and insufficient drug accumulation in the tumor region. Although many approaches, including various nanosystems, have been developed to promote the distribution of chemotherapeutics in the brain tumor, the delivery efficiency and the possible damage to the normal brain function still greatly restrict the clinical application of the nanocarriers. Therefore, it is urgent and necessary to discover more safe and effective BBB penetration and glioma-targeting strategies. In the present study, menthol, one of the strongest BBB penetration enhancers screened from traditional Chinese medicine, was conjugated to casein, a natural food protein with brain targeting capability. Then the conjugate self-assembled into the nanoparticles to load anti-cancer drugs. The nanoparticles were characterized to have appropriate size, spheroid shape and high loading drug capacity. Tumor spheroid penetration experiments demonstrated that penetration ability of menthol-modified casein nanoparticles (M-CA-NP) into the tumor were much deeper than that of unmodified nanoparticles. In vivo imaging further verified that M-CA-NPs exhibited higher brain tumor distribution than unmodified nanoparticles. The median survival time of glioma-bearing mice treated with HCPT-M-CA-NPs was significantly prolonged than those treated with free HCPT or HCPT-CA-NPs. HE staining of the organs indicated the safety of the nanoparticles. Therefore, the study combined the advantages of traditional Chinese medicine strategy with modern delivery technology for brain targeting, and provide a safe and effective approach for glioma therapy.

Brain targeting of resveratrol through intranasal lipid vesicles labelled with gold nanoparticles: in vivo evaluation and bioaccumulation investigation using computed tomography and histopathological examination

Resveratrol is a promising neuroprotective agent against neurodegenerative disorders such as Alzheimer's disease. Resveratrol-loaded transferosomes and nanoemulsions were developed and labelled with gold nanoparticles (GNPs). The water maze test was utilised to identify the effect on spatial memory recovery. The treated rats were examined for cellular uptake and bioaccumulation of drug in the brain using computed tomography (CT) and histopathological examination utilising GNPs as a biomarker. Compared with nanoemulsions, transferosomes displayed higher permeation of up to 81.29 ± 2.64% and higher fluorescence intensity with p < .05. Transferosomes significantly enhanced behavioural acquisition and spatial memory function in the amnesic rats compared with both the nanoemulsion formulation and the pure drug. CT effectively demonstrated the accumulation of GNPs in the brains of all treated rats, while superior accumulation of GNPs was observed in the rats that received the transferosome formulation. The histopathology also demonstrated GNP accumulation in the nuclei and cytoplasm in the brain tissues of both the transferosome- and nanoemulsion-treated groups. Therefore, the developed transferosomes may be considered as a well-designed brain targeting system that might further be applied for targeting many drugs to be used in the treatment of central nervous system diseases.

Functionalized liposomal nanoparticles for efficient gene delivery system to neuronal cell transfection

Liposome based delivery systems provide a promising strategy for treatment of neurodegenerative diseases. A rational design of brain-targeted liposomes can support the development of more efficient treatments with drugs and gene materials. Here, we characterized surface modified liposomes with transferrin (Tf) protein and penetratin (Pen), a cell-penetrating peptide, for efficient and targeted gene delivery to brain cells. PenTf-liposomes efficiently encapsulated plasmid DNA, protected them against enzymatic degradation and exhibited a sustained in vitro release kinetics. The formulation demonstrated low cytotoxicity and was non-hemolytic. Liposomes were internalized into cells mainly through energy-dependent pathways especially clathrin-mediated endocytosis. Reporter gene transfection and consequent protein expression in different cell lines were significantly higher using PenTf-liposomes compared to unmodified liposomes. The ability of these liposomes to escape from endosomes can be an important factor which may have likely contributed to the high transfection efficiency observed. Rationally designed bifunctional targeted-liposomes provide an efficient tool for improving the targetability and efficacy of synthesized delivery systems. This investigation of liposomal properties attempted to address cell differences, as well as, vector differences, in gene transfectability. The findings indicate that PenTf-liposomes can be a safe and non-invasive approach to transfect neuronal cells through multiple endocytosis pathways.

Ascorbic acid-modified brain-specific liposomes drug delivery system with "lock-in" function

In this study, a novel brain targeting ascorbic acid (AA) derivative with "lock-in" function was designed and synthesized as a liposome ligand to prepare novel liposomes to achieve the effective delivery of drug formulations to brain via glucose transporter 1 (GLUT₁) and the Na⁺-dependent vitamin C transporter (SVCT₂). The liposome was prepared and characterized in terms of the particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis and cell cytotoxicity. The preliminary evaluation in vivo demonstrated that the AA-thiamine disulfide system (TDS)-coated liposome had an improved targeting ability and significantly increased the brain concentration of docetaxel (DTX) as compared to the naked docetaxel, the non-coated and the AA-coated liposomes. The relative uptake efficiency and concentration efficiency were enhanced by 3.24- and 5.62-fold compared to that of the naked docetaxel, respectively. Both distribution data and pharmacokinetic parameters suggested that the ascorbic acid thiamine disulfide delivery system was a promising carrier to enhance central nervous system (CNS) drug's delivery ability into brain.

Intranasal delivery of α-asarone to the brain with lactoferrin-modified mPEG-PLA nanoparticles prepared by premix membrane emulsification

Alpha-asarone is a bioactive component of Acorus tatarincuii Schott with low bioavailability, which is often used for treatments of various brain diseases in clinical setting. This study was to formulate biodegradable methoxy polyethylene glycol-polylactic acid (mPEG-PLA) nanoparticles (NPs) surface-modified by lactoferrin (Lf), for delivering α-asarone into the brain following intranasal administration. Alpha-asarone NPs were prepared by premix membrane emulsification. The relative parameters were optimized by a Box-Behnken experimental design. The particle size, zeta potential, and dispersibility index of NPs and Lf-NPs were characterized. Their ex vivo permeation, pharmacokinetics, distribution in the brain and other tissue, brain targeting, and toxicity were investigated. Following intranasal administration, Lf-NPs had a better permeability and no significant poor bioavailability compared to NPs; the area under curve from 0 to 12 h of α-asarone in Lf-NPs of the olfactory bulb, hippocampus, olfactory bundles, and thalamus were 2.14-, 4.17-, 3.62-, and 1.96-fold of those in NP group, respectively. Lactoferrin could enhance the efficacy of brain targeting with NPs and reduce its liver accumulation. Toxicity of NPs on nasal mucosal cilia and epithelial cells was also decreased by Lf. To summarize, these results demonstrate that Lf-NPs of α-asarone have potential as a carrier for nose-to-brain delivery of α-asarone for brain diseases.

Dopamine-loaded blood exosomes targeted to brain for better treatment of Parkinson's disease

Parkinson's disease (PD), one of the most common movement and neurodegenerative disorders, is challenging to treat, largely because the blood-brain barrier blocks passage of most drugs. Here we find exosomes from blood showing natural brain targeting ability which involved the transferrin-transferrin receptor interaction. Thus, we develop a biocompatible platform based on blood exosomes for delivering drugs across the blood-brain barrier. Blood exosomes show sizes between 40 and 200 nm and spherical morphology, and dopamine can be efficiently loaded into blood exosomes by a saturated solution incubation method. Further in vitro and in vivo studies demonstrates these exosomes successfully delivered dopamine to brain, including the striatum and substantia nigra. Brain distribution of dopamine increased >15-fold by using the blood exosomes as delivery system. Dopamine-loaded exosomes show much better therapeutic efficacy in a PD mouse model and lower systemic toxicity than free dopamine after intravenous administration. These results suggest that blood exosomes can be used as a promising drug delivery platform for targeted therapy against PD and other diseases of the central nervous system.

A novel nasal almotriptan loaded solid lipid nanoparticles in mucoadhesive in situ gel formulation for brain targeting: Preparation, characterization and in vivo evaluation

This work aimed at designing efficient safe delivery system for intranasal (IN) brain targeting of the water soluble anti- migraine drug Almotriptan malate (ALM). Solid lipid nanoparticles (SLNs) were prepared by w/o/w double emulsion-solvent evaporation method. Selection of the optimized SLNs formula was based on evaluating particle size (PS), poly dispersity index (PDI) and entrapment efficiency (%EE). Optimized formula exhibited acceptable ranges; PS of 207.9 nm, PDI of 0.41 and %EE of 50.81%. Poloxamer 407 (Plx) at different concentrations (16%, 18%, 20% w/v), with different mucoadhesive polymers (Carbopol-974P, Na alginate, Na-CMC) were evaluated for gelling time and temperature, pH and mucoadhesion. The chosen mucoadhesive in-situ gel formula; 18% Plx 407 based-0.75%w/v Na-CMC, showed acceptable results, so that the optimized SLNs formula was further dispersed in it and evaluated for in vitro release, stability, in vivo and pharmacokinetics studies. Biomarkers' evaluation and histopathological examination were also investigated. Results revealed rapid ALM brain delivery of the optimized formula; Brain/blood ratios at 10 min. for NF (SLNs based IN in-situ gel), ND (Free ALM IN in situ gel) and ALM i.v. (ALM IV solution) were 0.89, 0.19 and 0.31, respectively. Toxicological results confirmed the safety of NF for nasal administration. The achieved out comings are encouraging for further clinical trials of the developed system in humans in future research.

Towards tailored management of malignant brain tumors with nanotheranostics

Malignant brain tumors still represent an unmet medical need given their rapid progression and often fatal outcome within months of diagnosis. Given their extremely heterogeneous nature, the assumption that a single therapy could be beneficial for all patients is no longer plausible. Hence, early feedback on drug accumulation at the tumor site and on tumor response to treatment would help tailor therapies to each patient's individual needs for personalized medicine. In this context, at the intersection between imaging and therapy, theranostic nanomedicine is a promising new technique for individualized management of malignant brain tumors. Although brain nanotheranostics has yet to be translated into clinical practice, this field is now a research hotspot due to the growing demand for personalized therapies. In this review, the barriers to the clinical implementation of theranostic nanomedicine for tracking tumor responses to treatment and for guiding stimulus-activated therapies and surgical resection of malignant brain tumors are discussed. Likewise, the criteria that nanotheranostic systems need to fulfil to become clinically relevant formulations are analyzed in depth, focusing on theranostic agents already tested in vivo. Currently, magnetic nanoparticles exploiting brain targeting strategies represent the first generation of preclinical theranostic nanomedicines for the management of malignant brain tumors.

STATEMENT OF SIGNIFICANCE

The development of nanocarriers that can be used both in imaging studies and the treatment of brain tumors could help identify which patients are most and least likely to respond to a given treatment. This will enable clinicians to adapt the therapy to the needs of the patient and avoid overdosing non-responders. Given the many different approaches to non-invasive techniques for imaging and treating brain tumors, it is important to focus on the strategies most likely to be implemented and to design the most feasible theranostic biomaterials that will bring nanotheranostics one step closer to clinical practice.

Memantine loaded PLGA PEGylated nanoparticles for Alzheimer's disease: in vitro and in vivo characterization

Background

Memantine, drug approved for moderate to severe Alzheimer’s disease, has not shown to be fully effective. In order to solve this issue, polylactic-co-glycolic (PLGA) nanoparticles could be a suitable solution to increase drug’s action on the target site as well as decrease adverse effects. For these reason, Memantine was loaded in biodegradable PLGA nanoparticles, produced by double emulsion method and surface-coated with polyethylene glycol. MEM–PEG–PLGA nanoparticles (NPs) were aimed to target the blood–brain barrier (BBB) upon oral administration for the treatment of Alzheimer’s disease.

Results

The production parameters were optimized by design of experiments. MEM–PEG–PLGA NPs showed a mean particle size below 200 nm (152.6 ± 0.5 nm), monomodal size distribution (polydispersity index, PI < 0.1) and negative surface charge (− 22.4 mV). Physicochemical characterization of NPs confirmed that the crystalline drug was dispersed inside the PLGA matrix. MEM–PEG–PLGA NPs were found to be non-cytotoxic on brain cell lines (bEnd.3 and astrocytes). Memantine followed a slower release profile from the NPs against the free drug solution, allowing to reduce drug administration frequency in vivo. Nanoparticles were able to cross BBB both in vitro and in vivo. Behavioral tests carried out on transgenic APPswe/PS1dE9 mice demonstrated to enhance the benefit of decreasing memory impairment when using MEM–PEG–PLGA NPs in comparison to the free drug solution. Histological studies confirmed that MEM–PEG–PLGA NPs reduced β-amyloid plaques and the associated inflammation characteristic of Alzheimer’s disease.

Conclusions

Memantine NPs were suitable for Alzheimer’s disease and more effective than the free drug.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0356-z) contains supplementary material, which is available to authorized users.

A brain targeting functionalized liposomes of the dopamine derivative N-3,4-bis(pivaloyloxy)-dopamine for treatment of Parkinson's disease

Parkinson's disease (PD) remains one of the most common neurodegenerative movement disorders with limited treatment options available. A dopamine derivative N-3,4-bis(pivaloyloxy)-dopamine (BPD) previously developed in our group has demonstrated superior therapeutic outcome compared to levodopa in a PD mice model. To further improve the therapeutic performance of BPD, a brain targeted drug delivery system was designed using a 29 amino-acid peptide (RVG29) derived from rabies virus glycoprotein as the targeting ligand. RVG29 functionalized liposomes (RVG29-lip) showed significantly higher uptake efficiency in murine brain endothelial cells and dopaminergic cells, and high penetration efficiency across the blood brain barrier (BBB) in vitro. In vivo and ex vivo distribution studies demonstrated RVG29-lip selectively distributed to the brain, striatum and substantia nigra. Furthermore, BPD loaded RVG29-lip (BPD-RVG29-lip) exhibited improved therapeutic efficacy in a PD mouse model, while causing no obvious systemic toxicity after intravenous administration. Thus, BPD-RVG29-lip represents a highly promising approach for the brain targeted treatment of PD.

Nanosystems in nose-to-brain drug delivery: A review of non-clinical brain targeting studies

The treatment of neurodegenerative and psychiatric disorders remains a challenge in medical research. Several strategies have been developed over the years, either to overcome the blood-brain barrier or to achieve a safer or faster brain delivery, one of them being intranasal (IN) administration. The possibility of direct nose-to-brain transport offers enhanced targeting and reduced systemic side effects. Nevertheless, labile, low soluble, low permeant and/or less potent drugs might need a formulation other than the common solutions or suspensions. For that, the formulation of nanosystems is considered to be a promising approach, since it can protect drugs from chemical and/or metabolic degradation, enhance their solubility, or offer transport through biological membranes. However, the understanding of the factors promoting efficient brain targeting when using nanosystems through the nasal route is currently patchy and incomplete. The main purpose of the present review was to evaluate the association between brain delivery efficacy (in terms of brain targeting, brain bioavailability and time to reach the brain) and nanosystem type. For that, we performed a systematic bibliographic search and analysis. Furthermore, study designs, nanosystem properties, and reporting quality were also analyzed and discussed. It was found a high heterogeneity in how pre-clinical brain targeting studies have been conducted, analyzed and reported in scientific literature, which surely originates a significant degree of bias and data dispersion. This review attempts to provide some systematization recommendations, which may be useful for researchers entering the field, and assist in increasing the uniformity of future reports. The analysis of literature data confirmed that there is evidence of the advantage of the IN route (when compared to the intravenous route) and in using carrier nanosystems (when compared to IN solutions) for brain delivery of a large set of drugs. Among the most represented nanosystem classes, microemulsions had some of the lowest pharmacokinetic ratios values, while polymeric micelles had some of the best. Nevertheless, brain targeting efficacy comparisons between nanosystem groups had little statistical significance, and the superiority of the polymeric micelles group disappeared when nanosystems were compared to the respective IN drug solutions. In fact, some drugs reached the brain so efficiently, even as drug solutions, that further benefit from formulating them into nanosystems became less evident.

Artificial apolipoprotein corona enables nanoparticle brain targeting

Many potential therapeutic compounds for brain diseases fail to reach their molecular targets due to the impermeability of the blood-brain barrier, limiting their clinical development. Nanotechnology-based approaches might improve compounds pharmacokinetics by enhancing binding to the cerebrovascular endothelium and translocation into the brain. Adsorption of apolipoprotein E4 onto polysorbate 80-stabilized nanoparticles to produce a protein corona allows the specific targeting of cerebrovascular endothelium. This strategy increased nanoparticle translocation into brain parenchyma, and improved brain nanoparticle accumulation 3-fold compared to undecorated particles (119.8 vs 40.5 picomoles). Apolipoprotein decorated nanoparticles have high clinical translational potential and may improve the development of nanotechnology-based medicine for a variety of neurological diseases.

Brain targeted delivery of mucoadhesive thermosensitive nasal gel of selegiline hydrochloride for treatment of Parkinson's disease

Selegiline hydrochloride (SL), is an anti-Parkinson's agent, has low-oral bioavailability due to its high first pass metabolism and scarce oral absorption. In the present study, SL mucoadhesive nasal thermosensitive gel (SNT-gel) was prepared to enhance the bioavailability and subsequently, its concentration in the brain. The SNT-gel was prepared using Poloxamer 407-Chitosan combination and optimised formulation was further evaluated for physicochemical parameters. The comparative pharmacodynamic studies including behavioural studies, biochemical testing and histopathology of the brain was carried out in rats for SNT-gel, SL-nasal solution and SL Marketed Tablets. The optimised SNT-gel formulation (SNT-V) revealed sol-gel transition at 33-34°C. In-vitro diffusion study of SNT-V showed 102.37 ± 2.1% diffusion at 12 h which reduced to 89.64 ± 1.2% in Ex-vivo diffusion. Comparative results of behavioural studies indicated an improved score of photoactometer and reduced motor deficit (catalepsy score) in SNT-gel treatment group as compared with other groups. Similarly, a significant increase in brain dopamine, reduction in monoamine oxidase B level, increase in catalase activity and level of reduced glutathione upon treatment with SNT-gel indicated its effectiveness which was also supported by histopathology results. Therefore, nasal thermosensitive gel holds better potential for brain targeting in Parkinson's disease over the conventional nasal or oral formulations.

Brain targeting efficiency of antimigrain drug loaded mucoadhesive intranasal nanoemulsion

Zolmitriptan (ZT) is a well-tolerated drug in migraine treatment suffering from low bioavailability due to low amount of the drug that reaches the brain after oral and nasal delivery. Development of new nasal mucoadhesive nanoemulsion formulation for zolmitriptan may success in delivering the drug directly from the nose to the brain to achieve rapid onset of action and high drug concentration in the brain which is required for treatment of acute migraine. ZT mucoadhesive nanoemulsion were prepared and characterized for drug content, zeta potential, particle size, morphology, residence time and permeation through the nasal mucosa. The selected formula was tested in-vivo in mice for its pharmacokinetics in comparison with intravenous and nasal solution of zolmitriptan. Results showed that addition of chitosan as mucoadhesive agent in 0.3% concentration to the nanoemulsion enhanced its residence time and zetapotential with no significant effect on the globule size. All tested formulations showed higher permeability coefficients than the zolmitriptan solution through the nasal mucosa. In-vivo studies showed that the mucoadhesive nanoemulsion formulation of zolmitriptan has higher AUC_0-8 and shorter T_max in the brain than the intravenous or the nasal solution. This was related to the small globule size and higher permeability of the formulation.

Self-assembled amphiphilic core-shell nanocarriers in line with the modern strategies for brain delivery

Disorders of the central nervous system (CNS) represent increasing social and economic problems all over the world which makes the effective transport of drugs to the brain a crucial need. In the last decade, many strategies were introduced to deliver drugs to the brain trying to overcome the challenge of the blood brain barrier (BBB) using both invasive and non-invasive methods. Non-invasive strategy represented in the application of nanocarriers became very common. One of the most hopeful nanoscopic carriers for brain delivery is core-shell nanocarriers or polymeric micelles (PMs). They are more advantageous than other nanocarriers. They offer small size, ease of preparation, ease of sterilization and the possibility of surface modification with various ligands. Hence, the aim of this review is to discuss modern strategies for brain delivery, micelles as a successful delivery system for the brain and how micelles could be modified to act as "magic bullets" for brain delivery.

Intranasal delivery of antipsychotic drugs

Antipsychotic drugs are used to treat psychotic disorders that afflict millions globally and cause tremendous emotional, economic and healthcare burdens. However, the potential of intranasal delivery to improve brain-specific targeting remains unrealized. In this article, we review the mechanisms and methods used for brain targeting via the intranasal (IN) route as well as the potential advantages of improving this type of delivery. We extensively review experimental studies relevant to intranasal delivery of therapeutic agents for the treatment of psychosis and mental illnesses. We also review clinical studies in which intranasal delivery of peptides, like oxytocin (7 studies) and desmopressin (1), were used as an adjuvant to antipsychotic treatment with promising results. Experimental animal studies (17) investigating intranasal delivery of mainstream antipsychotic drugs have revealed successful targeting to the brain as suggested by pharmacokinetic parameters and behavioral effects. To improve delivery to the brain, nanotechnology-based carriers like nanoparticles and nanoemulsions have been used in several studies. However, human studies assessing intranasal delivery of mainstream antipsychotic drugs are lacking, and the potential toxicity of nanoformulations used in animal studies has not been explored. A brief discussion of future directions anticipates that if limitations of low aqueous solubility of antipsychotic drugs can be overcome and non-toxic formulations used, IN delivery (particularly targeting specific tissues within the brain) will gain more importance moving forward given the inherent benefits of IN delivery in comparison to other methods.

Brain-Targeted Polymers for Gene Delivery in the Treatment of Brain Diseases

Gene therapies have become a promising strategy for treating neurological disorders, such as brain cancer and neurodegenerative diseases, with the help of molecular biology interpreting the underlying pathological mechanisms. Successful cellular manipulation against these diseases requires efficient delivery of nucleic acids into brain and further into specific neurons or cancer cells. Compared with viral vectors, non-viral polymeric carriers provide a safer and more flexible way of gene delivery, although suffering from significantly lower transfection efficiency. Researchers have been devoted to solving this defect, which is attributed to the multiple barriers existing for gene therapeutics in vivo, such as systemic degradation, blood-brain barrier, and endosome trapping. This review will be mainly focused on systemically administrated brain-targeted polymers developed so far, including PEI, dendrimers, and synthetic polymers with various functions. We will discuss in detail how they are designed to overcome these barriers and how they efficiently deliver therapeutic nucleic acids into targeted cells.

Docosahexaenoic acid-mediated, targeted and sustained brain delivery of curcumin microemulsion

We disclose microemulsions (ME) of curcumin (CUR) with docosahexaenoic acid (DHA)-rich oil (CUR DHA ME) for targeted delivery to the brain. MEs of CUR (5 mg/mL) with and without DHA-rich oil (CUR Capmul ME) suitable for intravenous and intranasal administration exhibited negative zeta potential, globule size  <20 nm and good stability. Following intravenous delivery MEs exhibited high brain concentration with CUR DHA ME exhibiting a 2.8-fold higher C_max than CUR solution. Furthermore, high and sustained concentration was demonstrated even at 24 h, which was 8- and 2-fold higher than CUR solution and CUR Capmul ME, respectively. Brain concentrations following intranasal administration were, however, substantially higher as evident from higher C_max and AUC and sustained compared to corresponding intravenous formulations signifying nose to brain targeting. The high brain concentration of CUR DHA ME is ascribed to the targeting efficiency enabled by DHA-mediated transport across the blood–brain barrier (BBB). Histopathological and nasal toxicity confirmed safety of the MEs. Concentration-dependent cytotoxicity in vitro, on human glioblastoma U-87MG cell line was observed with CUR DHA MEs and with the blank DHA ME, implying anticancer potential of DHA. The dramatically low IC₅₀ value of CUR DHA ME (3.755 ± 0.24 ng/mL) is therefore attributed to the synergistic effect of CUR and DHA in the ME. The CUR concentration achieved with CUR DHA ME at 24  h which translated to  >66-fold(intranasal) and  >21–fold (intravenous) the IC₅₀ value in the U-87MG cell line suggests great promise of CUR DHA ME for therapy of brain cancer by both routes.

Brain Targeting of 1,9-Pyrazoloanthrone an c-Jun-N-terminal Kinase Inhibitor Using Liposomes for Effective Management of Parkinson's Disease

The major challenge to treat Parkinson's disease (PD) is penetration of target molecule into the brain to improve the efficacy of drugs. To achieve better brain penetration and targeted delivery, 1,9-Pyrazoloanthrone (1,9-P) loaded liposomes were developed by solvent injection technique using ultrasonication and evaluated for particle size, morphology, entrapment efficiency, FT-IR, and in-vitro drug release studies. The potential of 1,9-Pyrazoloanthrone (1,9-P), a c-Jun-N-terminal Kinase (JNK-3) inhibitor which could stop or retard the rate of apoptosis of neuronal cells was also evaluated. In-vivo pharmacokinetic and brain uptake studies of liposomes were performed to investigate the bioavailability and brain distribution of 1,9-P. Cytotoxicity and neuroprotection were done on SH-SY5Y cell line using MTT and AO/EB apoptosis assay. The optimized batch of liposomes showed an average size of 112.33 ± 0.84 nm with a zeta potential value of -19.40 mV and 78.96 ± 0.28% drug entrapment efficiency. The in-vitro release studies demonstrated the sustained release profile of liposome up to 24 h. The pharmacokinetic data in Wistar rats over the period of 12 h demonstrated 4.82-folds greater AUC_{(0-12 h)} for liposome in brain compared with 1,9-P suspension. Cytotoxicity assay showed no sign of toxicity, whereas apoptosis assay revealed a neuroprotective action of liposomes. The results demonstrated successful targeting of the 1,9-P, to brain as a novel strategy having significant therapeutic potential to treat PD.

Nose-to-brain delivery of macromolecules mediated by cell-penetrating peptides

Brain delivery of macromolecular therapeutics (e.g., proteins) remains an unsolved problem because of the formidable blood–brain barrier (BBB). Although a direct pathway of nose-to-brain transfer provides an answer to circumventing the BBB and has already been intensively investigated for brain delivery of small drugs, new challenges arise for intranasal delivery of proteins because of their larger size and hydrophilicity. In order to overcome the barriers and take advantage of available pathways (e.g., epithelial tight junctions, uptake by olfactory neurons, transport into brain tissues, and intra-brain diffusion), a low molecular weight protamine (LMWP) cell-penetrating peptide was utilized to facilitate nose-to-brain transport. Cell-penetrating peptides (CPP) have been widely used to mediate macromolecular delivery through many kinds of biobarriers. Our results show that conjugates of LMWP–proteins are able to effectively penetrate into the brain after intranasal administration. The CPP-based intranasal method highlights a promising solution for protein therapy of brain diseases.

Progress and perspectives on targeting nanoparticles for brain drug delivery

Due to the ability of the blood-brain barrier (BBB) to prevent the entry of drugs into the brain, it is a challenge to treat central nervous system disorders pharmacologically. The development of nanotechnology provides potential to overcome this problem. In this review, the barriers to brain-targeted drug delivery are reviewed, including the BBB, blood-brain tumor barrier (BBTB), and nose-to-brain barrier. Delivery strategies are focused on overcoming the BBB, directly targeting diseased cells in the brain, and dual-targeted delivery. The major concerns and perspectives on constructing brain-targeted delivery systems are discussed.

In vitro screening of nanomedicines through the blood brain barrier: A critical review

The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed.

Trans-nasal zolmitriptan novasomes: in-vitro preparation, optimization and in-vivo evaluation of brain targeting efficiency

Migraine attack is a troublesome physiological condition associated with throbbing, intense headache, in one half of the head. Zolmitriptan is a potent second-generation triptan, prescribed for patients with migraine attacks, with or without an aura, and cluster headaches. The absolute bioavailability of zolmitriptan is about 40% for oral administration; due to hepatic first metabolism. Nasal administration would circumvent the pre-systemic metabolism thus increasing the bioavailability of zolmitriptan. In addition, due to the presence of microvilli and high vasculature, the absorption is expected to be faster compared to oral route. However, the bioavailability of nasal administered drugs is particularly restricted by poor membrane penetration. Thus, the aim of this work is to explore the potential of novel nanovesicular fatty acid enriched structures (novasomes) for effective and enhanced nasal delivery of zolmitriptan and investigate their nose to brain targeting potential. Novasomes were prepared using nonionic surfactant, cholesterol in addition to a free fatty acid. A 2³ full factorial design was adopted to study the influence of the type of surfactant, type of free fatty acid and ratio between the free fatty acid and the surfactant on novasomes properties. The particle size, entrapment efficiency, polydispersity index, zeta potential and % zolmitriptan released after 2 h were selected as dependent variables. Novasomes were further optimized using Design Expert® software (version 7; Stat-Ease Inc., Minneapolis, MN), and an optimized formulation composed of Span® 80:Cholesterol:stearic acid (in the ratio 1:1:1) was selected. This formulation showed zolmitriptan entrapment of 92.94%, particle size of 149.9 nm, zeta potential of -55.57 mV, and released 48.43% zolmitriptan after 2 h. The optimized formulation was further examined using transmission electron microscope, which revealed non-aggregating multi-lamellar nanovesicles with narrow size distribution. DSC, XRD examination of the optimized formulation confirmed that the drug have been homogeneously dispersed throughout the novasomes in an amorphous state. In-vivo bio-distribution studies of ^99mTc radio-labeled intranasal zolmitriptan loaded novasomes were done on mice, the pharmacokinetic parameters were compared with those following administration of intravenous ^99mTc-zolmitriptan solution. Results revealed the great enhancement in zolmitriptan targeting to the brain, with drug targeting potential of about 99% following intranasal administration of novasomes compared with the intravenous drug solution. Zolmitriptan loaded novasomes administered via the nasal route may therefore constitute an advance in the management of acute migraine attacks.

Intranasal delivery of nanoparticle encapsulated tarenflurbil: A potential brain targeting strategy for Alzheimer's disease

Poor brain penetration of tarenflurbil (TFB) was one of the major reasons for its failure in phase III clinical trials conducted on Alzheimer's patients. Thus there is a tremendous need of developing efficient delivery systems for TFB. This study was designed with the aim of improving drug delivery to brain through intranasally delivered nanocarriers. TFB was loaded into two different nanocarriers i.e., poly (lactide-co-glycolide) nanoparticles (TFB-NPs) and solid lipid nanoparticles (TFB-SLNs). Particle size of both the nanocarriers (<200nm) as determined by dynamic light scattering technique and transmission electron microscopy, assured transcellular transport across olfactory axons whose diameter was ≈200nm and then paving a direct path to brain. TFB-NPs and TFB-SLNs resulted in 64.11±2.21% and 57.81±5.32% entrapment efficiencies respectively which again asserted protection of drug from chemical and biological degradation in nasal cavity. In vitro release studies proved the sustained release of TFB from TFB-NPs and TFB-SLNs in comparison with pure drug, indicating prolonged residence times of drug at targeting site. Pharmacokinetics suggested improved circulation behavior of nanoparticles and the absolute bioavailabilities followed this order: TFB-NPs (i.n.)>TFB-SLNs (i.n.)>TFB solution (i.n.)>TFB suspension (oral). Brain targeting efficiency was determined in terms of %drug targeting efficiency (%DTE) and drug transport percentage (DTP). The higher %DTE (287.24) and DTP (65.18) were observed for TFB-NPs followed by TFB-SLNs (%DTE: 183.15 and DTP: 45.41) among all other tested groups. These encouraging results proved that therapeutic concentrations of TFB could be transported directly to brain via olfactory pathway after intranasal administration of polymeric and lipidic nanoparticles.

Non-invasive intranasal delivery of quetiapine fumarate loaded microemulsion for brain targeting: Formulation, physicochemical and pharmacokinetic consideration

Systemic drug delivery in schizophrenia is a major challenge due to presence of obstacles like, blood-brain barrier and P-glycoprotein, which prohibit entry of drugs into the brain. Quetiapine fumarate (QF), a substrate to P-glycoprotein under goes extensive first pass metabolism leading to limited absorption thus necessitating frequent oral administration. The aim of this study was to develop QF based microemulsion (ME) with and without chitosan (CH) to investigate its potential use in improving the bioavailability and brain targeting efficiency following non-invasive intranasal administration. QF loaded ME and mucoadhesive ME (MME) showed globule size, pH and viscosity in the range of 29-47nm, 5.5-6.5 and 17-40cP respectively. CH-ME with spherical globules having mean size of 35.31±1.71nm, pH value of 5.61±0.16 showed highest ex-vivo nasal diffusion (78.26±3.29%) in 8h with no sign of structural damage upon histopathological examination. Circular plume with an ovality ratio closer to 1.3 for CH-ME depicted ideal spray pattern. Significantly higher brain/blood ratio of CH-ME in comparison to QF-ME and drug solution following intranasal administration revealed prolonged retention of QF at site of action suggesting superiority of CH as permeability enhancer. Following intranasal administration, 2.7 and 3.8 folds higher nasal bioavailability in brain with CH-ME compared to QF-ME and drug solution respectively is indicative of preferential nose to brain transport (80.51±6.46%) bypassing blood-brain barrier. Overall, the above finding shows promising results in the area of developing non-invasive intranasal route as an alternative to oral route for brain delivery.

Design and evaluation of lipoprotein resembling curcumin-encapsulated protein-free nanostructured lipid carrier for brain targeting

Many nanoparticle matrixes have been demonstrated to be efficient in brain targeting, but there are still certain limitations for them. To overcome the shortcomings of the existing nanoparticulate systems for brain-targeted delivery, a lipoprotein resembling protein-free nanostructured lipid carrier (PS80-NLC) loaded with curcumin was constructed and assessed for in vitro and in vivo performance. Firstly, single factor at a time approach was employed to investigate the effects of various formulation factors. Mean particle sizes of ≤100nm, high entrapment efficiency (EE, about 95%) and drug loading (DL, >3%) were obtained for the optimized formulations. In vitro release studies in the presence of plasma indicated stability of the formulation under physiological condition. Compared with NLC, PS80-NLC showed noticeably higher affinity for bEnd.3 cells (1.56 folds greater than NLC) but with lower uptake in macrophages. The brain coronal sections showed strong and widely distributed fluorescence intensity of PS80-NLC than that of NLC in the cortex. Ex vivo imaging studies further confirmed that PS80-NLC could effectively permeate BBB and preferentially accumulate in the brain (2.38 times greater than NLC). The considerable in vitro and in vivo performance of the safe and biocompatible PS80-NLC makes it a suitable option for further investigations in brain targeted drug delivery.

Comparative study between simple and optimized liposomal dispersion of quetiapine fumarate for diffusion through nasal route

CONTEXT

Nasal route of drug administration is preferred more and more for the targeted delivery to the brain in current drug development scenario due to its ease of use, reliability, quick action, and lesser side effects. Those CNS drugs which have limited oral bioavailability due to pharmacokinetic consequences and brain barrier repulsion are getting onto this direction.

OBJECTIVE

Quetiapine fumarate, an analogous to above and an antischizophrenic agent, is tested for its diffusion property with and without lipophilic carrier through sheep nasal membrane. Being a BCS class II' and high permeable candidate, it tends to crossover easily, so made up in a simple dispersion.

MATERIALS AND METHODS

To improve its diffusion rate, it was embedded into liposomal dispersion, which has proven that it has advanced efficiency for diffusion. For this, both the formulations were checked and compared for their diffusion profile, as it is an essential property for bioavailability through nasal route. Comparison was made on the basis of % drug diffusion within 6 h, rate, mechanism, profile, and coefficient.

RESULTS

Liposomal dispersion has been proved superior with greater percentage diffusion of 32.61 ± 1.70 and very high permeability with a coefficient value of 4.1334 ± 0.7321 (× 10 (-) (5 )cm/s). Diffusion profile comparison bearing dissimilarity of 18 and similarity of 74 indicated that the diffusion profiles of liposomal dispersions and simple dispersion were similar but not identical.

CONCLUSION

Liposomal diffusion supremacy was further sustained by in vivo, ciliotoxicity, and gamma scintigraphy studies.

Surface engineered polymeric nanocarriers mediate the delivery of transferrin-methotrexate conjugates for an improved understanding of brain cancer

The objective of present study was to enhance permeation of bioactive molecules across blood brain barrier (BBB) through polysorbate 80 coated poly-lactic-co-glycolic acid (PLGA) nanoparticles (NPs) loaded with methotrexate-transferrin (Tw-Mtx-Tf-NP) conjugates (Mtx-Tf). The easy trans-BBB migration of developed formulations through endocytosis, and inhibition of P-gp efflux pump present in brain were established by Pluronic F-68 and/or polysorbate 80 (Tween 80/Tw). The over-expression of transferrin (Tf) receptors on cancer cell surface allowed targeted and sustained delivery of Mtx-Tf conjugated to brain cancer cells by receptor mediated endocytosis. The developed formulations showed improved penetration in comparison to non-targeting experimental NP controls. The transportation potential and bio-distribution studies of such nanosized polymeric carriers showing successful migration and trans-BBB passage was carried out by administering FITC labeled drug loaded NPs to albino rats through intravenous route. We have validated anti-tumor efficiency of newly formulated and drug loaded NPs compared to controls in experimentally induced tumor-harboring rat model. The present study suggests greater compatibility, less organ toxicity and higher anti-tumor activity of developed formulations due to their targeting and sustained delivery potential in cancer therapeutic interventions. In conclusion, our findings of targeted and sustained drug delivery potential of NPs for are corroborated with in vitro and in vivo evidence, and formulated novel delivery vehicle shows its value in developing new tools for treating brain cancer.

Parenteral nanoemulsions as promising carriers for brain delivery of risperidone: Design, characterization and in vivo pharmacokinetic evaluation

This paper describes design and evaluation of parenteral lecithin-based nanoemulsions intended for brain delivery of risperidone, a poorly water-soluble psychopharmacological drug. The nanoemulsions were prepared through cold/hot high pressure homogenization and characterized regarding droplet size, polydispersity, surface charge, morphology, drug-vehicle interactions, and physical stability. To estimate the simultaneous influence of nanoemulsion formulation and preparation parameters--co-emulsifier type, aqueous phase type, homogenization temperature--on the critical quality attributes of developed nanoemulsions, a general factorial experimental design was applied. From the established design space and stability data, promising risperidone-loaded nanoemulsions (mean size about 160 nm, size distribution <0.15, zeta potential around -50 mV), containing sodium oleate in the aqueous phase and polysorbate 80, poloxamer 188 or Solutol(®) HS15 as co-emulsifier, were produced by hot homogenization and their ability to improve risperidone delivery to the brain was assessed in rats. Pharmacokinetic study demonstrated erratic brain profiles of risperidone following intraperitoneal administration in selected nanoemulsions, most probably due to their different droplet surface properties (different composition of the stabilizing layer). Namely, polysorbate 80-costabilized nanoemulsion showed increased (1.4-7.4-fold higher) risperidone brain availability compared to other nanoemulsions and drug solution, suggesting this nanoemulsion as a promising carrier worth exploring further for brain targeting.

Design, characterization, and evaluation of intranasal delivery of ropinirole-loaded mucoadhesive nanoparticles for brain targeting

CONTEXT

Parkinson disease (PD) is a common, progressive neurodegenerative disorder, characterized by marked depletion of striatal dopamine and degeneration of dopaminergic neurons in the substantia nigra.

OBJECTIVE

The purpose of the present study was to investigate the possibility of targeting an anti-Parkinson's drug ropinirole (RH) to the brain using polymeric nanoparticles.

MATERIALS AND METHODS

Ropinirole hydrochloride (RH)-loaded chitosan nanoparticles (CSNPs) were prepared by an ionic gelation method. The RH-CSNPs were characterized for particle size, polydispersity index (PDI), zeta potential, loading capacity, entrapment efficiency in vitro release study, and in vivo distribution after intranasal administration.

RESULTS AND DISCUSSION

The RH-CSNPs showed sustained release profiles for up to 18 h. The RH concentrations (% Radioactivity/g) in the brain following intranasal administration (i.n.) of RH-CSNPs were found to be significantly higher at all the time points compared with RH solution. The concentration of RH was highest in the liver (7.210 ± 0.52), followed by kidneys (6.862 ± 0.62), intestine (4.862 ± 0.45), and lungs (4.640 ± 0.92) in rats following i.n. administration of RH-CSNPs. Gamma scintigraphy imaging in rats was performed to ascertain the localization of drug in the brain following intranasal administration of formulations. The brain/blood ratios obtained (0.251 ± 0.09 and 0.386 ± 0.57 of RH (i.n.) and RH-CSNPs (i.n.), respectively) at 0.5 h are indicative of direct nose to brain transport, bypassing the blood-brain barrier (BBB).

CONCLUSION

The novel formulation showed the superiority of nose to brain delivery of RH using mucoadhesive nanoparticles compared with other delivery routes reported earlier.

Solid lipid nanoparticles for nose to brain delivery of haloperidol: in vitro drug release and pharmacokinetics evaluation

In the present study, haloperidol (HP)-loaded solid lipid nanoparticles (SLNs) were prepared to enhance the uptake of HP to brain via intranasal (i.n.) delivery. SLNs were prepared by a modified emulsification–diffusion technique and evaluated for particle size, zeta potential, drug entrapment efficiency, in vitro drug release, and stability. All parameters were found to be in an acceptable range. In vitro drug release was found to be 94.16±4.78% after 24 h and was fitted to the Higuchi model with a very high correlation coefficient (R²=0.9941). Pharmacokinetics studies were performed on albino Wistar rats and the concentration of HP in brain and blood was measured by high performance liquid chromatography. The brain/blood ratio at 0.5 h for HP-SLNs i.n., HP sol. i.n. and HP sol. i.v. was 1.61, 0.17 and 0.031, respectively, indicating direct nose-to-brain transport, bypassing the blood–brain barrier. The maximum concentration (C_max) in brain achieved from i.n. administration of HP-SLNs (329.17±20.89 ng/mL, T_max 2 h) was significantly higher than that achieved after i.v. (76.95±7.62 ng/mL, T_max 1 h), and i.n. (90.13±6.28 ng/mL, T_max 2 h) administration of HP sol. The highest drug-targeting efficiency (2362.43%) and direct transport percentage (95.77%) was found with HP-SLNs as compared to the other formulations. Higher DTE (%) and DTP (%) suggest that HP-SLNs have better brain targeting efficiency as compared to other formulations.

Distribution of α-asarone in brain following three different routes of administration in rats

The goal of the present paper is to compare the distributions of α-asarone administered to rats through three different routes: oral, intravenous and intranasal. The concentrations of α-asarone in seven distinct brain regions, the olfactory bulb, cerebellum, hypothalamus, frontal cortex, striatum, hippocampus and medulla/pons as well as in plasma and cerebrospinal fluid (CSF), were determined by HPLC. The quantities of α-asarone accumulated in liver were measured to determine whether α-asarone could generate hepatotoxicity when administered via the three different routes. The results indicated that α-asarone could be absorbed via two different routes into the brain, after intranasal administration of dry powders. In the systemic route, α-asarone immediately entered the brain through the blood-brain barrier (BBB) after uptake into the circulatory system. In the olfactory bulb route, α-asarone traveled from the olfactory epithelium in the nasal cavity straight into brain tissue via the olfactory bulb. Furthermore, intranasal administration of α-asarone as a dry powder can ensure quick absorption and avoid excessive concentrations in the blood and liver, while achieving concentrations in the brain comparable to those attained by intravenous and oral administration routes.

Brain targeting by intranasal drug delivery (INDD): a combined effect of trans-neural and para-neuronal pathway

The effectiveness of intranasal drug delivery for brain targeting has emerged as a hope of remedy for various CNS disorders. The nose to brain absorption of therapeutic molecules claims two effective pathways, which include trans-neuronal for immediate action and para-neuronal for delayed action. To evaluate the contribution of both the pathways in absorption of therapeutic molecules and nanocarriers, lidocaine, a nerve-blocking agent, was used to impair the action potential of olfactory nerve. An anti-Parkinson drug ropinirole was covalently complexes with (99m)Tc in presence of SnCl2 using in-house developed reduction technology. The radiolabeled formulations were administered intranasally in lidocaine challenged rabbit and rat. The qualitative and quantitative outcomes of neural and non-neural pathways were estimated using gamma scintigraphy and UHPLC-MS/MS, respectively. The results showed a significant (p ≤ 0.005) increase in radioactivity counts and drug concentration in the brain of rabbit and rat compared to the animal groups challenged with lidocaine. This concludes the significant contribution (p ≤ 0.005) of trans-neuronal and para-neuronal pathway in nose to brain drug delivery. Therefore, results proved that it is an art of a formulator scientist to make the drug carriers to exploit the choice of absorption pathway for their instant and extent of action.

Design, synthesis and biological evaluation of brain targeting l-ascorbic acid prodrugs of ibuprofen with "lock-in" function

A novel brain targeting l-ascorbic acid derivatives with "lock-in" function were designed and synthesized as prodrugs to achieve the effective delivery of ibuprofen to brain by glucose transporter 1 (GLUT1) and the Na(+)-dependent vitamin C transporter SVCT2. Ibuprofen-loaded four prodrugs were tested in the animals. Results from the in vivo distribution study after i.v. administration of these four prodrugs and naked ibuprofen indicated that four prodrugs exhibited excellent transport ability across the BBB and significantly increased the level of ibuprofen in brain. Among them, prodrugs 4 showed higher brain concentration. Both biodistribution data and pharmacokinetic parameters suggested that l-ascorbic acid thiamine disulfide delivery system was a promising carrier to enhance CNS drug's delivery ability into brain.

Drug delivery to the central nervous system by polymeric nanoparticles: what do we know?

Nanoparticles enable the delivery of a great variety of drugs including anticancer drugs, analgesics, anti-Alzheimer's drugs, cardiovascular drugs, protease inhibitors, and several macromolecules into the brain after intravenous injection of animals. The mechanism of the nanoparticle-mediated drug transport across the BBB appears to be receptor-mediated endocytosis followed by transcytosis into the brain or by drug release within the endothelial cells. Modification of the nanoparticle surface with covalently attached targeting ligands or by coating with certain surfactants that lead to the adsorption of specific plasma proteins after injection is necessary for this receptor-mediated uptake. A very critical and important requirement for nanoparticulate brain delivery is that the employed nanoparticles are biocompatible and, moreover, rapidly biodegradable, i.e. over a time frame of a few days. In addition to enabling drug delivery to the brain, nanoparticles, as with doxorubicin, may importantly reduce the drug's toxicity and adverse effects due to an alteration of the body distribution. Because of the possibility to treat severe CNS diseases such as brain tumours and to even transport proteins and other macromolecules across the blood-brain barrier, this technology holds great promise for a non-invasive therapy of these diseases.

Identifying blood-brain-barrier selective single-chain antibody fragments

The blood-brain barrier (BBB) represents an obstacle in targeting and delivering therapeutics to the central nervous system. In order to discover new BBB-targeting molecules, we panned a phage-displayed nonimmune human single-chain antibody fragment (scFv) library against a representative BBB model comprised of hydrocortisone-treated primary rat brain endothelial cells. Parallel screens were performed with or without pre-subtraction against primary rat heart and lung endothelial cells in an effort to identify antibodies that may have binding selectivity toward brain endothelial cells. After three rounds of screening, three unique scFvs, scFv15, scFv38, and scFv29, were identified that maintained binding to primary rat brain endothelial cells, both in phage and soluble scFv format. While scFv29 and to a lesser extent, scFv15, exhibited some brain endothelial cell specificity in tissue culture, scFv29 did not appear to bind a BBB antigen in vivo. In contrast, both scFv15 and scFv38 were capable of immunolabeling rat brain vessels in vivo and displayed brain vascular selectivity with respect to all peripheral organs tested other than heart. Taken together, scFv15 and scFv38 represent two new antibodies that are capable of binding antigens that are expressed at the BBB in vivo.

Multimodal nanoprobes to target cerebrovascular amyloid in Alzheimer's disease brain

Cerebral amyloid angiopathy (CAA) results from the accumulation of Aβ proteins primarily within the media and adventitia of small arteries and capillaries of the cortex and leptomeninges. CAA affects a majority of Alzheimer's disease (AD) patients and is associated with a rapid decline in cognitive reserve. Unfortunately, there is no pre-mortem diagnosis available for CAA. Furthermore, treatment options are few and relatively ineffective. To combat this issue, we have designed nanovehicles (nanoparticles-IgG4.1) capable of targeting cerebrovascular amyloid (CVA) and serving as early diagnostic and therapeutic agents. These nanovehicles were loaded with Gadolinium (Gd) based (Magnevist(®)) magnetic resonance imaging contrast agents or single photon emission computed tomography (SPECT) agents, such as (125)I. In addition, the nanovehicles carry either anti-inflammatory and anti-amyloidogenic agents such as curcumin or immunosuppressants such as dexamethasone, which were previously shown to reduce cerebrovascular inflammation. Owing to the anti-amyloid antibody (IgG4.1) grafted on the surface, the nanovehicles are capable of specifically targeting CVA deposits. The nanovehicles effectively marginate from the blood flow to the vascular wall as determined by using quartz crystal microbalance with dissipation monitoring (QCM-D) technology. They demonstrate excellent distribution to the brain vasculature and target CVA, thus providing MRI and SPECT contrast specific to the CVA in the brain. In addition, they also display the potential to carry therapeutic agents to reduce cerebrovascular inflammation associated with CAA, which is believed to trigger hemorrhage in CAA patients.