Nanostructure-based drug delivery systems for brain targeting

Advancing the understanding of diabetic encephalopathy through unravelling pathogenesis and exploring future treatment perspectives

Diabetic encephalopathy (DE), a significant micro-complication of diabetes, manifests as neurochemical, structural, behavioral, and cognitive alterations. This condition is especially dangerous for the elderly because aging raises the risk of neurodegenerative disorders and cognitive impairment, both of which can be made worse by diabetes. Despite its severity, diagnosis of this disease is challenging, and there is a paucity of information on its pathogenesis. The pivotal roles of various cellular pathways, activated or influenced by hyperglycemia, insulin sensitivity, amyloid accumulation, tau hyperphosphorylation, brain vasculopathy, neuroinflammation, and oxidative stress, are widely recognized for contributing to the potential causes of diabetic encephalopathy. We also reviewed current pharmacological strategies for DE encompassing a comprehensive approach targeting metabolic dysregulations and neurological manifestations. Antioxidant-based therapies hold promise in mitigating oxidative stress-induced neuronal damage, while anti-diabetic drugs offer neuroprotective effects through diverse mechanisms, including modulation of insulin signaling pathways and neuroinflammation. Additionally, tissue engineering and nanomedicine-based approaches present innovative strategies for targeted drug delivery and regenerative therapies for DE. Despite significant progress, challenges remain in translating these therapeutic interventions into clinical practice, including long-term safety, scalability, and regulatory approval. Further research is warranted to optimize these approaches and address remaining gaps in the management of DE and associated neurodegenerative disorders.

Comparative Studies of the Uptake and Internalization Pathways of Different Lipid Nano-Systems Intended for Brain Delivery

Lipid nano-systems were prepared and characterized in a series of well-established in vitro tests that could assess their interactions with the hCMEC/D3 and SH-SY5Y cell lines as a model for the blood-brain barrier and neuronal function, accordingly. The prepared formulations of nanoliposomes and nanostructured lipid carriers were characterized by z-average diameters of ~120 nm and ~105 nm, respectively, following a unimodal particle size distribution (PDI < 0.3) and negative Z-potential (-24.30 mV to -31.20 mV). Stability studies implied that the nano-systems were stable in a physiologically relevant medium as well as human plasma, except nanoliposomes containing poloxamer on their surface, where there was an increase in particle size of ~26%. The presence of stealth polymer tends to decrease the amount of adsorbed proteins onto a particle's surface, according to protein adsorption studies. Both formulations of nanoliposomes were characterized by a low cytotoxicity, while their cell viability was reduced when incubated with the highest concentration (100 μg/mL) of nanostructured lipid formulations, which could have been associated with the consumption of cellular energy, thus resulting in a reduction in metabolic active cells. The uptake of all the nano-systems in the hCMEC/D3 and SH-SY5Y cell lines was successful, most likely following ATP-dependent internalization, as well as transport via passive diffusion.

Levodopa-loaded nanoparticles for the treatment of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) resulting in dopamine (DA) deficiency, which manifests itself in motor symptoms including tremors, rigidity and bradykinesia. Current PD treatments aim at symptom reduction through oral delivery of levodopa (L-DOPA), a precursor of DA. However, L-DOPA delivery to the brain is inefficient and increased dosages are required as the disease progresses, resulting in serious side effects like dyskinesias. To improve PD treatment efficacy and to reduce side effects, recent research focuses on the encapsulation of L-DOPA into polymeric- and lipid-based nanoparticles (NPs). These formulations can protect L-DOPA from systemic decarboxylation into DA and improve L-DOPA delivery to the central nervous system. Additionally, NPs can be modified with proteins, peptides and antibodies specifically targeting the blood-brain barrier (BBB), thereby reducing required dosages and free systemic DA. Alternative delivery approaches for NP-encapsulated L-DOPA include intravenous (IV) administration, transdermal delivery using adhesive patches and direct intranasal administration, facilitating increased therapeutic DA concentrations in the brain. This review provides an overview of the recent advances for NP-mediated L-DOPA delivery to the brain, and debates challenges and future perspectives on the field.

Potential of Lipid-Based Nanocarriers against Two Major Barriers to Drug Delivery-Skin and Blood-Brain Barrier

Over the past few years, pharmaceutical and biomedical areas have made the most astounding accomplishments in the field of medicine, diagnostics and drug delivery. Nanotechnology-based tools have played a major role in this. The implementation of this multifaceted nanotechnology concept encourages the advancement of innovative strategies and materials for improving patient compliance. The plausible usage of nanotechnology in drug delivery prompts an extension of lipid-based nanocarriers with a special reference to barriers such as the skin and blood-brain barrier (BBB) that have been discussed in the given manuscript. The limited permeability of these two intriguing biological barriers restricts the penetration of active moieties through the skin and brain, resulting in futile outcomes in several related ailments. Lipid-based nanocarriers provide a possible solution to this problem by facilitating the penetration of drugs across these obstacles, which leads to improvements in their effectiveness. A special emphasis in this review is placed on the composition, mechanism of penetration and recent applications of these carriers. It also includes recent research and the latest findings in the form of patents and clinical trials in this field. The presented data demonstrate the capability of these carriers as potential drug delivery systems across the skin (referred to as topical, dermal and transdermal delivery) as well as to the brain, which can be exploited further for the development of safe and efficacious products.

Exploring the role of nanomedicines for the therapeutic approach of central nervous system dysfunction: At a glance

In recent decades, research scientists, molecular biologists, and pharmacologists have placed a strong emphasis on cutting-edge nanostructured materials technologies to increase medicine delivery to the central nervous system (CNS). The application of nanoscience for the treatment of neurodegenerative diseases (NDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), Huntington’s disease (HD), brain cancer, and hemorrhage has the potential to transform care. Multiple studies have indicated that nanomaterials can be used to successfully treat CNS disorders in the case of neurodegeneration. Nanomedicine development for the cure of degenerative and inflammatory diseases of the nervous system is critical. Nanoparticles may act as a drug transporter that can precisely target sick brain sub-regions, boosting therapy success. It is important to develop strategies that can penetrate the blood–brain barrier (BBB) and improve the effectiveness of medications. One of the probable tactics is the use of different nanoscale materials. These nano-based pharmaceuticals offer low toxicity, tailored delivery, high stability, and drug loading capacity. They may also increase therapeutic effectiveness. A few examples of the many different kinds and forms of nanomaterials that have been widely employed to treat neurological diseases include quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These unique qualities, including sensitivity, selectivity, and ability to traverse the BBB when employed in nano-sized particles, make these nanoparticles useful for imaging studies and treatment of NDs. Multifunctional nanoparticles carrying pharmacological medications serve two purposes: they improve medication distribution while also enabling cell dynamics imaging and pharmacokinetic study. However, because of the potential for wide-ranging clinical implications, safety concerns persist, limiting any potential for translation. The evidence for using nanotechnology to create drug delivery systems that could pass across the BBB and deliver therapeutic chemicals to CNS was examined in this study.

Targeted Delivery Platforms for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative condition of the central nervous system (CNS) that presents with varying levels of disability in patients, displaying the significance of timely and effective management of this complication. Though several treatments have been developed to protect nerves, comprehensive improvement of MS is still considered an essential bottleneck. Therefore, the development of innovative treatment methods for MS is one of the core research areas. In this regard, nanoscale platforms can offer practical and ideal approaches to the diagnosis and treatment of various diseases, especially immunological disorders such as MS, to improve the effectiveness of conventional therapies. It should be noted that there is significant progress in the development of neuroprotective strategies through the implementation of various nanoparticles, monoclonal antibodies, peptides, and aptamers. In this study, we summarize different particle systems as well as targeted therapies, such as antibodies, peptides, nucleic acids, and engineered cells for the treatment of MS, and discuss their potential in the treatment of MS in the preclinical and clinical stages. Future advances in targeted delivery of medical supplies may offer new strategies for complete recovery as well as practical treatment of progressive forms of MS.

Design and evaluation of nanostructured lipid carriers loaded with Salvia officinalis extract for Alzheimer's disease treatment

Considering the potential of Salvia officinalis in prevention and treatment of Alzheimer's disease (AD), as well as the ability of nanostructured lipid carriers (NLC) to successfully deliver drug molecules across blood-brain barrier (BBB), the objective of this study was design, development, optimization and characterization of freeze-dried salvia officinalis extract (FSE) loaded NLC intended for intranasal administration. NLC were prepared by solvent evaporation method and the optimization was carried out using central composite design (CCD) of experiments. Further, the optimized formulation (NLCo) was coated either with chitosan (NLCc) or poloxamer (NLCp). Surface characterization of the particles demonstrated a spherical shape with smooth exterior. Particle size of optimal formulations after 0.45 μm pore size filtration ranged from 127 ± 0.68 nm to 140 ± 0.74 nm. The zeta potential was -25.6 ± 0.404 mV; 22.4 ± 1.106 mV and - 6.74 ± 0.609 mV for NLCo, NLCc, and NLCp, respectively. Differential scanning calorimetry (DSC) confirmed the formation of NLC whereas Fourier-transform infrared spectroscopy confirmed the FSE encapsulation into particles. All formulations showcased relatively high drug loading (>86.74 mcg FSE/mg solid lipid) and were characterized by prolonged and controlled release that followed Peppas-Sahlin in vitro release kinetic model. Protein adsorption studies revealed the lowest adsorption of the proteins onto NLCp (43.53 ± 0.07%) and highest protein adsorption onto NLCc (55.97 ± 0.75%) surface. The modified ORAC assay demonstrated higher antioxidative activity for NLCo (95.31 ± 1.86%) and NLCc (97.76 ± 4.00%) as compared to FSE (90.30 ± 1.53%). Results obtained from cell cultures tests pointed to the potential of prepared NLCs for FSE brain targeting and controlled release.

The role of efflux transporters and metabolizing enzymes in brain and peripheral organs to explain drug-resistant epilepsy

Drug‐resistant epilepsy has been explained by different mechanisms. The most accepted one involves overexpression of multidrug transporters proteins at the blood brain barrier and brain metabolizing enzymes. This hypothesis is one of the main pharmacokinetic reasons that lead to the lack of response of some antiseizure drug substrates of these transporters and enzymes due to their limited entrance into the brain and limited stay at the sites of actions. Although uncontrolled seizures can be the cause of the overexpression, some antiseizure medications themselves can cause such overexpression leading to treatment failure and thus refractoriness. However, it has to be taken into account that the inductive effect of some drugs such as carbamazepine or phenytoin not only impacts on the brain but also on the rest of the body with different intensity, influencing the amount of drug available for the central nervous system. Such induction is not only local drug concentration but also time dependent. In the case of valproic acid, the deficient disposition of ammonia due to a malfunction of the urea cycle, which would have its origin in an intrinsic deficiency of L‐carnitine levels in the patient or by its depletion caused by the action of this antiseizure drug, could lead to drug‐resistant epilepsy. Many efforts have been made to change this situation. In order to name some, the administration of once‐daily dosing of phenytoin or the coadministration of carnitine with valproic acid would be preferable to avoid iatrogenic refractoriness. Another could be the use of an adjuvant drug that down‐regulates the expression of transporters. In this case, the use of cannabidiol with antiseizure properties itself and able to diminish the overexpression of these transporters in the brain could be a novel therapy in order to allow penetration of other antiseizure medications into the brain.

Lipid nanostructures for targeting brain cancer

Advancements in both material science and bionanotechnology are transforming the health care sector. To this end, nanoparticles are increasingly used to improve diagnosis, monitoring, and therapy. Huge research is being carried out to improve the design, efficiency, and performance of these nanoparticles. Nanoparticles are also considered as a major area of research and development to meet the essential requirements for use in nanomedicine where safety, compatibility, biodegradability, biodistribution, stability, and effectiveness are requirements towards the desired application. In this regard, lipids have been used in pharmaceuticals and medical formulations for a long time. The present work focuses on the use of lipid nanostructures to combat brain tumors. In addition, this review summarizes the literature pertaining to solid lipid nanoparticles (SLN) and nanostructured lipid carriers (LNC), methods of preparation and characterization, developments achieved to overcome blood brain barrier (BBB), and modifications used to increase their effectiveness.

Small Molecules of Marine Origin as Potential Anti-Glioma Agents

Marine organisms are able to produce a plethora of small molecules with novel chemical structures and potent biological properties, being a fertile source for discovery of pharmacologically active compounds, already with several marine-derived agents approved as drugs. Glioma is classified by the WHO as the most common and aggressive form of tumor on CNS. Currently, Temozolomide is the only chemotherapeutic option approved by the FDA even though having some limitations. This review presents, for the first time, a comprehensive overview of marine compounds described as anti-glioma agents in the last decade. Nearly fifty compounds were compiled in this document and organized accordingly to their marine sources. Highlights on the mechanism of action and ADME properties were included. Some of these marine compounds could be promising leads for the discovery of new therapeutic alternatives for glioma treatment.

Noble Metals and Soft Bio-Inspired Nanoparticles in Retinal Diseases Treatment: A Perspective

We are witnessing an exponential increase in the use of different nanomaterials in a plethora of biomedical fields. We are all aware of how nanoparticles (NPs) have influenced and revolutionized the way we supply drugs or how to use them as therapeutic agents thanks to their tunable physico-chemical properties. However, there is still a niche of applications where NP have not yet been widely explored. This is the field of ocular delivery and NP-based therapy, which characterizes the topic of the current review. In particular, many efforts are being made to develop nanosystems capable of reaching deeper sections of the eye such as the retina. Particular attention will be given here to noble metal (gold and silver), and to polymeric nanoparticles, systems consisting of lipid bilayers such as liposomes or vesicles based on nonionic surfactant. We will report here the most relevant literature on the use of different types of NPs for an efficient delivery of drugs and bio-macromolecules to the eyes or as active therapeutic tools.

Polymeric Nanoparticles for the Treatment of Malignant Gliomas

Malignant gliomas are one of the deadliest forms of brain cancer and despite advancements in treatment, patient prognosis remains poor, with an average survival of 15 months. Treatment using conventional chemotherapy does not deliver the required drug dose to the tumour site, owing to insufficient blood brain barrier (BBB) penetration, especially by hydrophilic drugs. Additionally, low molecular weight drugs cannot achieve specific accumulation in cancerous tissues and are characterized by a short circulation half-life. Nanoparticles can be designed to cross the BBB and deliver their drugs within the brain, thus improving their effectiveness for treatment when compared to administration of the free drug. The efficacy of nanoparticles can be enhanced by surface PEGylation to allow more specificity towards tumour receptors. This review will provide an overview of the different therapeutic strategies for the treatment of malignant gliomas, risk factors entailing them as well as the latest developments for brain drug delivery. It will also address the potential of polymeric nanoparticles in the treatment of malignant gliomas, including the importance of their coating and functionalization on their ability to cross the BBB and the chemistry underlying that.

Ligand Conjugated Targeted Nanotherapeutics for Treatment of Neurological Disorders

BACKGROUND

Human brain is amongst the most complex organs in human body, and delivery of therapeutic agents across the brain is a tedious task. Existence of blood brain barrier (BBB) protects the brain from invasion of undesirable substances; therefore it hinders the transport of various drugs used for the treatment of different neurological diseases including glioma, Parkinson's disease, Alzheimer's disease, etc. To surmount this barrier, various approaches have been used such as the use of carrier mediated drug delivery; use of intranasal route, to avoid first pass metabolism; and use of ligands (lactoferrin, apolipoprotein) to transport the drug across the BBB. Ligands bind with proteins present on the cell and facilitate the transport of drug across the cell membrane via. receptor mediated, transporter mediated or adsorptive mediated transcytosis.

OBJECTIVE

The main focus of this review article is to illustrate various studies performed using ligands for delivering drug across BBB; it also describes the procedure used by various researchers for conjugating the ligands to the formulation to achieve targeted action.

METHODS

Research articles that focused on the used of ligand conjugation for brain delivery and compared the outcome with unconjugated formulation were collected from various search engines like PubMed, Science Direct and Google Scholar, using keywords like ligands, neurological disorders, conjugation, etc. Results and Conclusion: Ligands have shown great potential in delivering drug across BBB for treatment of various diseases, yet extensive research is required so that the ligands can be used clinically for treating neurological diseases.

Enhancement of drug permeability across blood brain barrier using nanoparticles in meningitis

The central nervous system, one of the most delicate microenvironments of the body, is protected by the blood-brain barrier regulating its homeostasis. Blood-brain barrier is a highly complex structure that tightly regulates the movement of ions of a limited number of small molecules and of an even more restricted number of macromolecules from the blood to the brain, protecting it from injuries and diseases. However, the blood-brain barrier also significantly precludes the delivery of drugs to the brain, thus, preventing the therapy of a number of neurological disorders. As a consequence, several strategies are currently being sought after to enhance the delivery of drugs across the blood-brain barrier. Within this review a brief description of the structural and physiological features of the barriers and the recently born strategy of brain drug delivery based on the use of nanoparticles are described. Finally, the future technological approaches are described. The strong efforts to allow the translation from preclinical to concrete clinical applications are worth the economic investments.

Ameliorating the in vivo antimalarial efficacy of artemether using nanostructured lipid carriers

Cerebral malaria (CM) is a fatal neurological complication of Plasmodium falciparum infection that affects children (below five years old) in sub-Saharan Africa and adults in South-East Asia each year having the fatality rate of 10-25%. The survivors of CM also have high risk of long term neurological or cognitive deficits. The objective of the present investigation was to develop optimised nanostructured lipid carriers (NLCs) of artemether (ARM) for enhanced anti-malarial efficacy of ARM. NLCs of ARM were prepared by a combination of high speed homogenisation (HSH) and probe sonication techniques. Preliminary solubility studies for ARM showed highest solubility in trimyristin (solid lipid), capmul MCM NF (liquid lipid) and polysorbate 80 (surfactant). Trimyristin and capmul showed superior miscibility at a ratio of 70:30.The optimised NLC formulation has the particle size (PS) of: 48.59 ± 3.67 nm, zeta potential (ZP) of: -32 ± 1.63 mV and entrapment efficiency (EE) of: 91 ± 3.62%. In vitro cell line (human embryonic kidney fibroblast cell line (HEK 293 T)) cytotoxicity studies showed that prepared formulation was non-toxic. The results of in vivo studies in CM induced mice prevented the recrudescence of parasite after administration of NLCs of ARM. Additionally, NLCs of ARM showed better parasite clearance, higher survival (60%) in comparison to ARM solution (40%). Also it was observed that lesser entrapment of Evans blue stain (prepared in PBS as solution) in the NLCs of ARM treated brains of C57BL/6 mice than ARM solution treated mice. Hence NLCs of ARM may be a better alternative for improving therapeutic efficacy than ARM solution.

Advances in the design of solid lipid nanoparticles and nanostructured lipid carriers for targeting brain diseases

Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) comprise a category of versatile drug delivery systems that have been used in the biomedical field for >25years. SLNs and NLCs have been used for the treatment of various diseases including cardiovascular and cerebrovascular, and are considered a standard treatment for the latter, due to their inherent ability to cross the blood brain barrier (BBB). In this review, a presentation of the most important brain diseases (brain cancer, ischemic stroke, Alzheimer's disease, Parkinson's disease and multiple sclerosis) is approached, followed by the basic fabrication techniques of SLNs and NLCs. A detailed description of the reported studies of the last seven years, of active and passive targeting SLNs and NLCs for the treatment of glioblastoma multiforme and of other brain cancers, as well as for the treatment of neurodegenerative diseases is also carried out. Finally, a brief description of the advantages, the disadvantages, and the future perspectives in the use of these nanocarriers is reported, aiming at giving an insight of the limitations that have to be overcome in order to result in a delivery system with high therapeutic efficacy and without the limitations of the existing nano-systems.

A potential non-invasive glioblastoma treatment: Nose-to-brain delivery of farnesylthiosalicylic acid incorporated hybrid nanoparticles

New drug delivery systems are highly needed in research and clinical area to effectively treat gliomas by reaching a high antineoplastic drug concentration at the target site without damaging healthy tissues. Intranasal (IN) administration, an alternative route for non-invasive drug delivery to the brain, bypasses the blood-brain-barrier (BBB) and eliminates systemic side effects. This study evaluated the antitumor efficacy of farnesylthiosalicylic acid (FTA) loaded (lipid-cationic) lipid-PEG-PLGA hybrid nanoparticles (HNPs) after IN application in rats. FTA loaded HNPs were prepared, characterized and evaluated for cytotoxicity. Rat glioma 2 (RG2) cells were implanted unilaterally into the right striatum of female Wistar rats. 10days later, glioma bearing rats received either no treatment, or 5 repeated doses of 500μM freshly prepared FTA loaded HNPs via IN or intravenous (IV) application. Pre-treatment and post-treatment tumor sizes were determined with MRI. After a treatment period of 5days, IN applied FTA loaded HNPs achieved a significant decrease of 55.7% in tumor area, equal to IV applied FTA loaded HNPs. Herewith, we showed the potential utility of IN application of FTA loaded HNPs as a non-invasive approach in glioblastoma treatment.

Farnesylthiosalicylic acid-loaded lipid-polyethylene glycol-polymer hybrid nanoparticles for treatment of glioblastoma

OBJECTIVES

We aimed to develop lipid-polyethylene glycol (PEG)-polymer hybrid nanoparticles, which have high affinity to tumour tissue with active ingredient, a new generation antineoplastic drug, farnesylthiosalicylic acid (FTA) for treatment of glioblastoma.

METHOD

Farnesylthiosalicylic acid-loaded poly(lactic-co-glycolic acid)-1,2 distearoyl-glycerol-3-phospho-ethanolamine-N [methoxy (PEG)-2000] ammonium salt (PLGA-DSPE-PEG) with or without 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) hybrid nanoparticles has been prepared and evaluated for in-vitro characterization. Cytotoxicity of FTA-loaded nanoparticles along with its efficacy on rat glioma-2 (RG2) cells was also evaluated both in vitro (in comparison with non-malignant cell line, L929) and in vivo.

KEY FINDINGS

Scanning electron microscopy studies showed that all formulations prepared had smooth surface and spherical in shape. FTA and FTA-loaded nanoparticles have cytotoxic activity against RG2 glioma cell lines in cell culture studies, which further increases with addition of DOTAP. Magnetic resonance imaging and histopathologic evaluation on RG2 tumour cells in rat glioma model (49 female Wistar rats, 250-300 g) comparing intravenous and intratumoral injections of the drug have been performed and FTA-loaded nanoparticles reduced tumour size significantly in in-vivo studies, with higher efficiency of intratumoral administration than intravenous route.

CONCLUSION

Farnesylthiosalicylic acid-loaded PLGA-DSPE-PEG-DOTAP hybrid nanoparticles are proven to be effective against glioblastoma in both in-vitro and in-vivo experiments.

Nanoparticulate strategies for the treatment of polyglutamine diseases by halting the protein aggregation process

Polyglutamine (polyQ) diseases are a class of neurodegenerative disorders that cause cellular dysfunction and, eventually, neuronal death in specific regions of the brain. Neurodegeneration is linked to the misfolding and aggregation of expanded polyQ-containing proteins, and their inhibition is one of major therapeutic strategies used commonly. However, successful treatment has been limited to date because of the intrinsic properties of therapeutic agents (poor water solubility, low bioavailability, poor pharmacokinetic properties), and difficulty in crossing physiological barriers, including the blood-brain barrier (BBB). In order to solve these problems, nanoparticulate systems with dimensions of 1-1000 nm able to incorporate small and macromolecules with therapeutic value, to protect and deliver them directly to the brain, have recently been developed, but their use for targeting polyQ disease-mediated protein misfolding and aggregation remains scarce. This review provides an update of the polyQ protein aggregation process and the development of therapeutic strategies for halting it. The main features that a nanoparticulate system should possess in order to enhance brain delivery are discussed, as well as the different types of materials utilized to produce them. The final part of this review focuses on the potential application of nanoparticulate system strategies to improve the specific and efficient delivery of therapeutic agents to the brain for the treatment of polyQ diseases.

Computer Optimization of Biodegradable Nanoparticles Fabricated by Dispersion Polymerization

Quality by design (QbD) in the pharmaceutical industry involves designing and developing drug formulations and manufacturing processes which ensure predefined drug product specifications. QbD helps to understand how process and formulation variables affect product characteristics and subsequent optimization of these variables vis-à-vis final specifications. Statistical design of experiments (DoE) identifies important parameters in a pharmaceutical dosage form design followed by optimizing the parameters with respect to certain specifications. DoE establishes in mathematical form the relationships between critical process parameters together with critical material attributes and critical quality attributes. We focused on the fabrication of biodegradable nanoparticles by dispersion polymerization. Aided by a statistical software, d-optimal mixture design was used to vary the components (crosslinker, initiator, stabilizer, and macromonomers) to obtain twenty nanoparticle formulations (PLLA-based nanoparticles) and thirty formulations (poly-ɛ-caprolactone-based nanoparticles). Scheffe polynomial models were generated to predict particle size (nm), zeta potential, and yield (%) as functions of the composition of the formulations. Simultaneous optimizations were carried out on the response variables. Solutions were returned from simultaneous optimization of the response variables for component combinations to (1) minimize nanoparticle size; (2) maximize the surface negative zeta potential; and (3) maximize percent yield to make the nanoparticle fabrication an economic proposition.

Nanoparticles as potential new generation broad spectrum antimicrobial agents

The rapid emergence of antimicrobial resistant strains to conventional antimicrobial agents has complicated and prolonged infection treatment and increased mortality risk globally. Furthermore, some of the conventional antimicrobial agents are unable to cross certain cell membranes thus, restricting treatment of intracellular pathogens. Therefore, the disease-causing-organisms tend to persist in these cells. However, the emergence of nanoparticle (NP) technology has come with the promising broad spectrum NP-antimicrobial agents due to their vast physiochemical and functionalization properties. In fact, NP-antimicrobial agents are able to unlock the restrictions experienced by conventional antimicrobial agents. This review discusses the status quo of NP-antimicrobial agents as potent broad spectrum antimicrobial agents, sterilization and wound healing agents, and sustained inhibitors of intracellular pathogens. Indeed, the perspective of developing potent NP-antimicrobial agents that carry multiple-functionality will revolutionize clinical medicine and play a significant role in alleviating disease burden.

Nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease

Alzheimer's disease is a neurological disorder that results in cognitive and behavioral impairment. Conventional treatment strategies, such as acetylcholinesterase inhibitor drugs, often fail due to their poor solubility, lower bioavailability, and ineffective ability to cross the blood-brain barrier. Nanotechnological treatment methods, which involve the design, characterization, production, and application of nanoscale drug delivery systems, have been employed to optimize therapeutics. These nanotechnologies include polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and liquid crystals. Each of these are promising tools for the delivery of therapeutic devices to the brain via various routes of administration, particularly the intranasal route. The objective of this study is to present a systematic review of nanotechnology-based drug delivery systems for the treatment of Alzheimer's disease.

Enhanced anti-ischemic stroke of ZL006 by T7-conjugated PEGylated liposomes drug delivery system

The treatment for ischemic stroke is one of the most challenging problems and the therapeutic effect remains unsatisfied due to the poor permeation of drugs across the blood brain barrier (BBB). In this study, HAIYPRH (T7), a peptide that targeted to transferrin receptor (TfR) can mediate the transport of nanocarriers across the BBB, was conjugated to liposomes for ischemic stroke targeting treatment of a novel neuroprotectant (ZL006). T7-conjugated PEGylated liposomes (T7-P-LPs) loaded with ZL006 (T7-P-LPs/ZL006) were showed satisfactory vesicle size and size distribution. Furthermore, the cellular uptake results showed that T7 modification increased liposomes uptake by the brain capillary endothelial cells (BCECs) and little cytotoxicity of liposomes with or without ZL006 was observed. The in vivo biodistribution and near-infrared fluorescence imaging evidenced that T7 modification rendered liposomes significantly enhanced the transport of liposomes across the BBB. The pharmacodynamic study suggested that, T7-P-LPs/ZL006 exhibited reduced infarct volume and ameliorated neurological deficit compared with unmodified liposomes or free ZL006. T7-P-LPs/ZL006 could be targeted to brain and displayed remarkable neuroprotective effects. They could be used as a potential targeted drug delivery system of ischemic stroke treatment.

In situ nasal gel drug delivery: A novel approach for brain targeting through the mucosal membrane

Recently, sustained and controlled drug delivery has become the demand, and research has been undertaken in achieving much better drug product effectiveness, reliability and safety. The in situ polymeric system has gained much attention, to develop a controlled release system. It has been used as a vehicle for local and systemic drug delivery. Nowadays, it has created much interest, because of its characteristics of high vascularization, high permeability, rapid onset of action, low enzymatic degradation, and avoidance of hepatic first pass metabolism. The main aim of this review is to provide knowledge of different mechanisms of nasal absorption and approaches for nasal drug delivery.

Enhanced brain delivery of lamotrigine with Pluronic(®) P123-based nanocarrier

BACKGROUND

P-glycoprotein (P-gp) mediated drug efflux across the blood-brain barrier (BBB) is an important mechanism underlying poor brain penetration of certain antiepileptic drugs (AEDs). Nanomaterials, as drug carriers, can overcome P-gp activity and improve the targeted delivery of AEDs. However, their applications in the delivery of AEDs have not been adequately investigated. The objective of this study was to develop a nano-scale delivery system to improve the solubility and brain penetration of the antiepileptic drug lamotrigine (LTG).

METHODS

LTG-loaded Pluronic(®) P123 (P123) polymeric micelles (P123/LTG) were prepared by thin-film hydration, and brain penetration capability of the nanocarrier was evaluated.

RESULTS

The mean encapsulating efficiency for the optimized formulation was 98.07%; drug-loading was 5.63%, and particle size was 18.73 nm. The solubility of LTG in P123/LTG can increase to 2.17 mg/mL, making it available as a solution. The in vitro release of LTG from P123LTG presented a sustained-release property. Compared with free LTG, the LTG-incorporated micelles accumulated more in the brain at 0.5, 1, and 4 hours after intravenous administration in rats. Pretreatment with systemic verapamil increased the rapid brain penetration of free LTG but not P123/LTG. Incorporating another P-gp substrate (Rhodamine 123) into P123 micelles also showed higher efficiency in penetrating the BBB in vitro and in vivo.

CONCLUSION

These results indicated that P123 micelles have the potential to overcome the activity of P-gp expressed on the BBB and therefore show potential for the targeted delivery of AEDs. Future studies are necessary to further evaluate the appropriateness of the nanocarrier to enhance the efficacy of AEDs.

Development and evaluation of brain targeted intranasal alginate nanoparticles for treatment of depression

The purpose of the present study was to investigate the potential of Venlafaxine loaded alginate nanoparticles (VLF AG-NPs) for treatment of depression via intranasal (i.n.) nose to brain delivery route. The VLF AG-NPs were prepared and optimized on the basis of various physio-chemical characteristics. Pharmacodynamic studies of the VLF AG-NPs for antidepressant activity were carried in-vivo by forced swimming test and locomotor activity test on albino Wistar rats. VLF AG-NPsi.n. treatment significantly improved the behavioural analysis parameters i.e. swimming, climbing, and immobility in comparison to the VLF solutioni.n. and VLF tabletoral. The intranasal VLF AG-NPs also improved locomotor activity when compared with VLF solutioni.n. and VLF tabletoral. Confocal laser scanning fluorescence microscopy studies were performed on isolated organs of rats after intravenous and intranasal administrations of Rodamine-123 loaded alginate nanoparticles to determine its efficacy for nose to brain delivery and also for its qualitative distribution to other organs. Brain uptake and pharmacokinetic studies were performed by determination of VLF concentration in blood and brain respectively for VLF AG-NPsi.n., VLF solutioni.n. and VLF solutioni.v. The greater brain/blood ratios for VLF AG-NPsi.n. in comparison to VLF solutioni.n. and VLF solutioni.v. respectively at 30 min are indicative of superiority of alginate nanoparticles for direct nose to brain transport of VLF. Thus, VLF AG-NPsi.n. delivered greater VLF to the brain in comparison to VLF solution which indicates that VLF AG-NPs could be a promising approach for the treatment of depression.

Nanoparticles for brain drug delivery

The central nervous system, one of the most delicate microenvironments of the body, is protected by the blood-brain barrier (BBB) regulating its homeostasis. BBB is a highly complex structure that tightly regulates the movement of ions of a limited number of small molecules and of an even more restricted number of macromolecules from the blood to the brain, protecting it from injuries and diseases. However, the BBB also significantly precludes the delivery of drugs to the brain, thus, preventing the therapy of a number of neurological disorders. As a consequence, several strategies are currently being sought after to enhance the delivery of drugs across the BBB. Within this review, the recently born strategy of brain drug delivery based on the use of nanoparticles, multifunctional drug delivery systems with size in the order of one-billionth of meters, is described. The review also includes a brief description of the structural and physiological features of the barrier and of the most utilized nanoparticles for medical use. Finally, the potential neurotoxicity of nanoparticles is discussed, and future technological approaches are described. The strong efforts to allow the translation from preclinical to concrete clinical applications are worth the economic investments.

Caveolar uptake and endothelial-protective effects of nanostructured lipid carriers in acid aspiration murine acute lung injury

PURPOSE

Nanostructured lipid carriers (NLC), nanosized phospholipids/triglyceride particles developed for drug delivery, are considered biologically inactive. We assessed the efficacy of unloaded NLC as experimental treatment for acute lung injury (ALI).

METHODS

To induce ALI, C57Black/6 male mice received intratracheal injections of HCl or saline; A single dose of 16 mg/Kg NLC or saline was injected intravenously concomitantly with HCl challenge. NLC uptake mechanisms and effects on endothelial permeability and signaling were studied in cultured endothelial cells and neutrophils.

RESULTS

NLC pre-treatment attenuated pulmonary microvascular protein leak, airspace inflammatory cells, thrombin proteolytic activity and histologic lung injury score 24 h post insult. Using fluorescence measurements and flow cytometry in mouse lung microvascular endothelial cell culture homogenates, we determined that NLC rendered fluorescent by curcumin labeling are taken up by endothelial cells from mice expressing caveolin-1, the coat protein of caveolar endocytic vesicles, but not from caveolin-1 gene-disrupted mice, which lack caveolae. In contrast, conventional emulsions (CE), consisting of larger particles, were not incorporated. In addition, NLC pre-treatment of cultured human lung microvascular endothelial cells abrogated thrombin-induced activation of p44/42, albumin permeability response, actin cytoskeletal remodeling and interleukin-6 production. Finally, NLC but not CE abrogated lipopolysaccharide-triggered interleukin-8 release.

CONCLUSIONS

NLC are engulfed by endothelial caveolae and possess endothelial-protective effects. These novel properties may be of potential utility in ALI.

Rivastigmine-loaded L-lactide-depsipeptide polymeric nanoparticles: decisive formulation variable optimization

The main aim of the investigation was to explore a novel L-lactide-depsipeptide copolymer for the development of rivastigmine-loaded polymeric nanoparticles. L-lactide-depsipeptide synthesis was based on the ring opening polymerization reaction of L-lactide with the cyclodepsipeptide, cyclo(Glc-Leu), using tin 2-ethyl hexanoate as an initiator. Rivastigmine-loaded nanoparticles were prepared by the single emulsion-solvent evaporation technique. The influence of various critical formulation variables like sonication time, amount of polymer, amount of drug, stabilizer concentration, drug-to-polymer ratio, and organic-to-aqueous phase ratio on particle size and entrapment efficiency was studied. The optimized formulation having a particle size of 142.2 ± 21.3 nm with an entrapment efficiency of 60.72 ± 3.72% was obtained. Increased rivastigmine entrapment within the polymer matrix was obtained with a relatively low organic-to-aqueous phase ratio and high drug-to-polymer ratio. A decrease in the average size of the nanoparticles was observed with a decrease in the amount of polymer added and an increase in the sonication time. Prolonged sonication time, however, decreased rivastigmine entrapment. From the different lyoprotectant tested, only trehalose was found to prevent nanoparticle aggregation upon application of the freeze-thaw cycle. Drug incorporation into the polymeric matrix was confirmed by the DSC and XRD study. The spherical nature of the nanoparticles was confirmed by the SEM study. The in vitro drug release study showed the sustained release of more than 90% of the drug up to 72 h. Thus, L-lactide-depsipeptide can be used as an efficient carrier for the nanoparticle preparation of rivastigmine.

Preparation, characterization, in vivo biodistribution and pharmacokinetic studies of donepezil-loaded PLGA nanoparticles for brain targeting

OBJECTIVE

Alzheimer's disease (AD) is a progressive neurodegenerative disorder manifested by cognitive, memory deterioration and variety of neuropsychiatric symptoms. Donepezil is a reversible cholinesterase inhibitor used for the treatment of AD. The purpose of this work is to prepare a nanoparticulate drug delivery system of donepezil using poly(lactic-co-glycolic acid) (PLGA) for sustained release and efficient brain targeting.

MATERIALS AND METHODS

PLGA nanoparticles (NPs) were prepared by the solvent emulsification diffusion-evaporation technique and characterized for particle size, particle-size distribution, zeta potential, entrapment efficiency, drug loading and interaction studies and in vivo studies using gamma scintigraphy techniques.

RESULTS AND DISCUSSION

The size of drug-loaded NPs (drug polymer ratio 1:1) was found to be 89.67 ± 6.43 nm. The TEM and SEM images of the formulation suggested that particle size was within 20-100 nm and spherical in shape, smooth morphology and coating of Tween-80 on the NPs was clearly observed. The release behavior of donepezil exhibited a biphasic pattern characterized by an initial burst release followed by a slower and continuous sustained release. The biodistribution studies of donepezil-loaded PLGA NPs and drug solution via intravenous route revealed higher percentage of radioactivity per gram in the brain for the nanoparticulate formulation as compared with the drug solution (p < 0.05).

CONCLUSION

The high concentrations of donepezil uptake in brain due to coated NPs may help in a significant improvement for treating AD. But further, more extensive clinical studies are needed to check and confirm the efficacy of the prepared drug delivery system.

Altered plasma and brain disposition of isopropylidene shikimic acid liposome in rats and the brain protection in cerebral ischemia-reperfusion

CONTEXT

Cerebral ischemia-reperfusion (I/R) injury is a secondary injury caused by oxidative stresses and inflammatory responses after recovery from cerebral ischemia. Brain protective drugs were used to reduce the injury. In order to improve the distribution in brain and enhance the brain-protective efficacy, some pharmaceutical technologies were used to achieve brain targeting delivery.

OBJECTIVE

To investigate the physiological disposition of ISA liposome, and provide references for the further study about high-efficacy brain-protective preparations for I/R injury.

MATERIALS AND METHODS

Comparative studies were carried out. The pharmacodynamics in t-MCAO model rats were studied first, and then the pharmacokinetics and brain distribution of the two preparations were determined.

RESULTS

At the same dose, the efficacy of ISA liposome was better (P < 0.05). The efficacy was dose dependent, with significant difference of 20 mg/kg (P < 0.01) and indistinctive difference of 10 mg/kg (P = 0.22), compared with vehicle-treated rats. The parameters, T(1/2β), MRT and AUC were different significantly between the two preparations. The enhancement of brain distribution for ISA in the liposome was obvious, with the maximum concentration 7.18 μg/g, while close to zero for the solution group.

DISCUSSION AND CONCLUSION

ISA liposome could increase the distribution in brain and enhance the efficacy significantly. The results revealed that the liposomal DDS was potential as a novel strategy for the treatment of cerebral I/R injury. In addition, further targeted modification, such as PEG-modified liposomes, which possess a long circulating property in the bloodstream, would further improve the targeting delivery to the brain and lead to more significant efficacy.