Brain-targeted, drug-loaded solid lipid nanoparticles against glioblastoma cells in culture

Small Scale, Big Impact: Nanotechnology-Enhanced Drug Delivery for Brain Diseases

Central nervous system (CNS) diseases, ranging from brain cancers to neurodegenerative disorders like dementia and acute conditions such as strokes, have been heavily burdening healthcare and have a direct impact on patient quality of life. A significant hurdle in developing effective treatments is the presence of the blood-brain barrier (BBB), a highly selective barrier that prevents most drugs from reaching the brain. The tight junctions and adherens junctions between the endothelial cells and various receptors expressed on the cells make the BBB form a nonfenestrated and highly selective structure that is crucial for brain homeostasis but complicates drug delivery. Nanotechnology offers a novel pathway to circumvent this barrier, with nanoparticles engineered to ferry drugs across the BBB, protect drugs from degradation, and deliver medications to the designated area. After years of development, nanoparticle optimization, including sizes, shapes, surface modifications, and targeting ligands, can enable nanomaterials tailored to specific brain drug delivery settings. Moreover, smart nano drug delivery systems can respond to endogenous and exogenous stimuli that control subsequent drug release. Here, we address the importance of the BBB in brain disease treatment, summarize different delivery routes for brain drug delivery, discuss the cutting-edge nanotechnology-based strategies for brain drug delivery, and further offer valuable insights into how these innovations in nanoparticle technology could revolutionize the treatment of CNS diseases, presenting a promising avenue for noninvasive, targeted therapeutic interventions.

Overcoming Barriers in Glioblastoma-Advances in Drug Delivery Strategies

The world of cancer treatment is evolving rapidly and has improved the prospects of many cancer patients. Yet, there are still many cancers where treatment prospects have not (or hardly) improved. Glioblastoma is the most common malignant primary brain tumor, and even though it is sensitive to many chemotherapeutics when tested under laboratory conditions, its clinical prospects are still very poor. The blood-brain barrier (BBB) is considered at least partly responsible for the high failure rate of many promising treatment strategies. We describe the workings of the BBB during healthy conditions and within the glioblastoma environment. How the BBB acts as a barrier for therapeutic options is described as well as various approaches developed and tested for passing or opening the BBB, with the ultimate aim to allow access to brain tumors and improve patient perspectives.

Nanomedicine facilitated cell signaling blockade: difficulties and strategies to overcome glioblastoma

Glioblastoma (GBM) is a highly aggressive and lethal type of brain tumor with complex and diverse molecular signaling pathways involved that are in its development and progression. Despite numerous attempts to develop effective treatments, the survival rate remains low. Therefore, understanding the molecular mechanisms of these pathways can aid in the development of targeted therapies for the treatment of glioblastoma. Nanomedicines have shown potential in targeting and blocking signaling pathways involved in glioblastoma. Nanomedicines can be engineered to specifically target tumor sites, bypass the blood-brain barrier (BBB), and release drugs over an extended period. However, current nanomedicine strategies also face limitations, including poor stability, toxicity, and low therapeutic efficacy. Therefore, novel and advanced nanomedicine-based strategies must be developed for enhanced drug delivery. In this review, we highlight risk factors and chemotherapeutics for the treatment of glioblastoma. Further, we discuss different nanoformulations fabricated using synthetic and natural materials for treatment and diagnosis to selectively target signaling pathways involved in GBM. Furthermore, we discuss current clinical strategies and the role of artificial intelligence in the field of nanomedicine for targeting GBM.

Tadpole-Like Anisotropic Polymer/Lipid Janus Nanoparticles for Nose-to-Brain Drug Delivery: Importance of Geometry, Elasticity on Mucus-Penetration Ability

Asymmetric geometry (aspect ratio >1), moderate stiffness (i.e., semielasticity), large surface area, and low mucoadhesion of nanoparticles are the main features to reach the brain by penetrating across the nasal mucosa. Herein, a new application has been presented for the use of multifunctional Janus nanoparticles (JNPs) with controllable geometry and size as a nose-to-brain (N2B) delivery system by changing proportions of Precirol ATO 5 and polycaprolactone compartments and other operating conditions. To bring to light the N2B application of JNPs, the results are presented in comparison with polymer and solid lipid nanoparticles, which are frequently used in the literature regarding their biopharmaceutical aspects: mucoadhesion and permeability through the nasal mucosa. The morphology and geometry of JPs were observed via cryogenic-temperature transmission electron microscopy images, and their particle sizes were verified by dynamic light scattering, atomic force microscopy, and scanning electron microscopy. Although all NPs showed penetration across the mucus barrier, the best increase in penetration was observed with asymmetric and semielastic JNPs, which have low interaction ability with the mucus layer. This study presents a new and promising field of application for a multifunctional system suitable for N2B delivery, potentially benefiting the treatment of brain tumors and other central nervous system diseases.

A two-pronged approach against glioblastoma: drug repurposing and nanoformulation design for in situ-controlled release

Glioblastoma (GB) is one of the most lethal types of neoplasms. Its biologically aggressive nature and the presence of the blood-brain barrier (BBB) limit the efficacy of standard therapies. Several strategies are currently being developed to both overcome the BBB and deliver drugs site specifically to tumor cells. This work hypothesizes a two-pronged approach to tackle GB: drug repurposing with celecoxib (CXB) and a nanoformulation using ultra-small nanostructured lipid carriers (usNLCs). CXB antitumor druggable activity was inspected bioinformatically and screened in four glioma cell lines aiming at the comparison with temozolomide (TMZ), as standard of care. Delving into formulation design, it was tailored aiming at (i) improving the drug solubility/loading properties, (ii) assigning a thermal-triggerable drug release based on a lipid matrix with a low melting point, and (iii) enhancing the cytotoxic effect by selecting a template targetable to tumor cells. For this purpose, an integrated analysis of the critical material attributes (CMAs), critical process parameters (CPPs), and critical quality attributes (CQAs) was conducted under the umbrella of a quality by design approach. CMAs that demonstrate a high-risk level for the final quality and performance of the usNLCs include the drug solubility in lipids (solid and liquid), the lipid composition (envisioning a thermoresponsive approach), the ratio between lipids (solid vs. liquid), and the surfactant type and concentration. Particle size was shown to be governed by the interaction lipid-surfactant followed by surfactant type. The drug encapsulation did not influence colloidal characteristics, making it a promising carrier for lipophilic drugs. In general, usNLCs exhibited a controlled drug release during the 72 h at 37 °C with a final release of ca. 25%, while at 45 °C this was doubled. The in vitro cellular performance depended on the surfactant type and lipid composition, with the formulations containing a sole solid lipid (Suppocire® NB) and Kolliphor® RH40 as surfactant being the most cytotoxic. usNLCs with an average diameter of ca. 70 nm and a narrow size distribution (PdI lower than 0.2) were yielded, exhibiting high stability, drug protection, sustained and thermo-sensitive release properties, and high cytotoxicity to glioma cells, meeting the suitable CQAs for parenteral administration. This formulation may pave the way to a multi-addressable purpose to improve GB treatment.

Nanoparticle-Based Treatment in Glioblastoma

Glioblastoma (GB) is a malignant glioma associated with a mean overall survival of 12 to 18 months, even with optimal treatment, due to its high relapse rate and treatment resistance. The standardized first-line treatment consists of surgery, which allows for diagnosis and cytoreduction, followed by stereotactic fractionated radiotherapy and chemotherapy. Treatment failure can result from the poor passage of drugs through the blood-brain barrier (BBB). The development of novel and more effective therapeutic approaches is paramount to increasing the life expectancy of GB patients. Nanoparticle-based treatments include epitopes that are designed to interact with specialized transport systems, ultimately allowing the crossing of the BBB, increasing therapeutic efficacy, and reducing systemic toxicity and drug degradation. Polymeric nanoparticles have shown promising results in terms of precisely directing drugs to the brain with minimal systemic side effects. Various methods of drug delivery that pass through the BBB, such as the stereotactic injection of nanoparticles, are being actively tested in vitro and in vivo in animal models. A significant variety of pre-clinical studies with polymeric nanoparticles for the treatment of GB are being conducted, with only a few nanoparticle-based drug delivery systems to date having entered clinical trials. Pre-clinical studies are key to testing the safety and efficacy of these novel anticancer therapies and will hopefully facilitate the testing of the clinical validity of this promising treatment method. Here we review the recent literature concerning the most frequently reported types of nanoparticles for the treatment of GB.

The Role of Biological Rhythms in New Drug Formulations to Cross the Brain Barriers

For brain protection, the blood-brain barrier and blood-cerebrospinal fluid barrier limit the traffic of molecules between blood and brain tissue and between blood and cerebrospinal fluid, respectively. Besides their protective function, brain barriers also limit the passage of therapeutic drugs to the brain, which constitutes a great challenge for the development of therapeutic strategies for brain disorders. This problem has led to the emergence of novel strategies to treat neurological disorders, like the development of nanoformulations to deliver therapeutic agents to the brain. Recently, functional molecular clocks have been identified in the blood-brain barrier and in the blood-cerebrospinal fluid barrier. In fact, circadian rhythms in physiological functions related to drug disposition were also described in brain barriers. This opens the possibility for chronobiological approaches that aim to use time to improve drug efficacy and safety. The conjugation of nanoformulations with chronobiology for neurological disorders is still unexplored. Facing this, here, we reviewed the circadian rhythms in brain barriers, the nanoformulations studied to deliver drugs to the brain, and the nanoformulations with the potential to be conjugated with a chronobiological approach to therapeutic strategies for the brain.

Hybrid lipid-biopolymer nanocarrier as a strategy for GBM photodynamic therapy (PDT)

Glioblastoma (GBM) is the most common brain cancer characterized by aggressive and infiltrated tumors. For this, hybrid biopolymer-lipid nanoparticles coated with biopolymers such-as chitosan and lipidic nanocarriers (LN) loaded with a photosensitizer (AlClPc) can be used for GBM photodynamic therapy. The chitosan-coated LN exhibited stable physicochemical characteristics and presented as an excellent lipid nanocarrier with highly efficiently encapsulated photosensitizer chloro-aluminum phthalocyanine (AlClPc). LN(AlClPc)Ct0.1 % in the presence of light produced more reactive oxygen species and reduced brain tumor cell viability and proliferation. Confirm the effects in vivo LN applications with photodynamic therapy confirmed that the total brain tumor area decreased without systemic toxicity in mice. These results suggest a promising strategy for future clinical applications to improve brain cancer treatment.

Drug delivery to the brain – lipid nanoparticles-based approach

The complex structure of the human brain defines it as one of the most inaccessible organs in terms of drug delivery. The blood-brain barrier (BBB) represents a microvascular network involved in transporting substances between the blood and the central nervous system (CNS) – enabling the entry of nutrients and simultaneously restricting the influx of pathogens and toxins. However, its role as a protective shield for CNS also restricts drug access to the brain. Since many drugs cannot cross the BBB due to unsuitable physicochemical characteristics (i.e., high molecular weight, aqueous solubility, etc.), different technological strategies have been developed to ensure sufficient drug bioavailability. Among these, solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are promising approaches thanks to their lipid nature, facilitating their brain uptake, small sizes, and the possibilities for subsequent functionalization to achieve targeted delivery. The review focuses on applying SLNs and NLCs as nanocarriers for brain delivery, outlining the physiological factors of BBB and the physicochemical characteristics of nanocarriers influencing this process. Recent advances in this area have also been summarized.

Strategies to overcome/penetrate the BBB for systemic nanoparticle delivery to the brain/brain tumor

Despite its prevalence in the management of peripheral tumors, compared to surgery and radiation therapy, chemotherapy is still a suboptimal intervention in fighting against brain cancer and cancer brain metastases. This discrepancy is mainly derived from the complicatedly physiological characteristic of intracranial tumors, including the presence of blood-brain barrier (BBB) and limited enhanced permeability and retention (EPR) effect attributed to blood-brain tumor barrier (BBTB), which largely lead to insufficient therapeutics penetrating to tumor lesions to produce pharmacological effects. Therefore, dependable methodologies that can boost the efficacy of chemotherapy for brain tumors are urgently needed. Recently, nanomedicines have shown great therapeutic potential in brain tumors by employing various transcellular strategies, paracellular strategies, and their hybrids, such as adsorptive-mediated transcytosis, receptor-mediated transcytosis, BBB disruption technology, and so on. It is compulsory to comprehensively summarize these practices to shed light on future directions in developing therapeutic regimens for brain tumors. In this review, the biological and pathological characteristics of brain tumors, including BBB and BBTB, are illustrated. After that, the emerging delivery strategies for brain tumor management are summarized into different classifications and supported with detailed examples. Finally, the potential challenges and prospects for developing and clinical application of brain tumor-oriented nanomedicine are discussed.

Development of WRAP5 Peptide Complexes for Targeted Drug/Gene Co-Delivery toward Glioblastoma Therapy

Despite the great progress over the past few decades in both the diagnosis and treatment of a great variety of human cancers, glioblastoma remains the most lethal brain tumor. In recent years, cancer gene therapy focused on non-viral vectors which emerged as a promising approach to glioblastoma treatment. Transferrin (Tf) easily penetrates brain cells of the blood–brain barrier, and its receptor is highly expressed in this barrier and glioblastoma cells. Therefore, the development of delivery systems containing Tf appears as a reliable strategy to improve their brain cells targeting ability and cellular uptake. In this work, a cell-penetrating peptide (WRAP5), bearing a Tf-targeting sequence, has been exploited to condense tumor suppressor p53-encoding plasmid DNA (pDNA) for the development of nanocomplexes. To increase the functionality of developed nanocomplexes, the drug Temozolomide (TMZ) was also incorporated into the formulations. The physicochemical properties of peptide/pDNA complexes were revealed to be dependent on the nitrogen to phosphate groups ratio and can be optimized to promote efficient cellular internalization. A confocal microscopy study showed the capacity of developed complexes for efficient glioblastoma cell transfection and consequent pDNA delivery into the nucleus, where efficient gene expression took place, followed by p53 protein production. Of promise, these peptide/pDNA complexes induced a significant decrease in the viability of glioblastoma cells. The set of data reported significantly support further in vitro research to evaluate the therapeutic potential of developed complexes against glioblastoma.

Brain targeted delivery of carmustine using chitosan coated nanoparticles via nasal route for glioblastoma treatment

This study aims to develop chitosan-coated PLGA nanoparticles intended for nose-to-brain delivery of carmustine. Formulations were prepared by the double emulsion solvent evaporation method and optimized by using Box-Behnken Design. The optimized nanoparticles were obtained to satisfactory levels in terms of particle size, PDI, entrapment efficiency, and drug loading. In vitro drug release and ex-vivo permeation showed sustained release and enhanced permeability (approx. 2 fold) of carmustine compared to drug suspension. The AUC_0-t of brain obtained with carmustine-loaded nanoparticles via nasal administration in Albino Wistar rats was 2.8 and 14.7 times that of intranasal carmustine suspension and intravenous carmustine, respectively. The MTT assay on U87 MG cell line showed a significant decrease (P < 0.05) in the IC50 value of the formulation (71.23 μg ml^-1) as compared to drug suspension (90.02 μg ml^-1).These findings suggest chitosan coated nanoparticles could be used to deliver carmustine via intranasal administration to treat Glioblastoma multiforme.

Temozolomide hexadecyl ester targeted plga nanoparticles for drug-resistant glioblastoma therapy via intranasal administration

Introduction: Temozolomide (TMZ) is the first-line drug for glioblastoma (GBM), but it is limited in clinical use due to the drug resistance, poor brain targeting, and side effects. Temozolomide hexadecyl ester (TMZ16e), a TMZ derivative with high lipophilicity, membrane permeability, and high anti-glioma properties, has the potential to reverse drug resistance. In this study, anti-ephrin type-A receptor 3 (EphA3) modified TMZ16e loaded nanoparticles (NPs) were prepared for targeted GBM therapy via intranasal administration to deliver TMZ16e to the brain, treat drug-resistant glioma effectively, and reduce peripheral toxicity.

Methods: TMZ16e loaded NPs were prepared by emulsion solvent evaporation method followed by modified with anti-EphA3 (anti-EphA3-TMZ16e-NPs). In vitro evaluations were performed by an MTT assay and flow cytometry analysis. The orthotopic nude mice models were used to evaluate the anti-glioma effect in vivo. Additionally, we investigated the anti-drug resistant mechanism by western blot analysis.

Results: The particle size of the prepared NPs was less than 200 nm, and the zeta potential of TMZ16e-NPs and anti-EphA3-TMZ16e-NPs were -23.05 ± 1.48 mV and -28.65 ± 1.20mV, respectively, which is suitable for nasal delivery. In vitro studies have shown that anti-EphA3 modification increased the cellular uptake of nanoparticles in T98G cells. The cytotoxicity in the anti-EphA3-TMZ16e-NPs treated group was significantly higher than that of the TMZ16e-NPs, TMZ16e, and TMZ groups (p < 0.01), and the cell cycle was blocked. Western blotting analysis showed that the TMZ16e-loaded NPs were able to effectively downregulate the expression level of O6-methylguanine-deoxyribonucleic acid-methyltransferase (MGMT) protein in T98G cells and reverse drug resistance. In vivo studies showed that the median survival time of tumor-bearing nude mice in the anti-EphA3-TMZ16e-NPs group was extended to 41 days, which was 1.71-fold higher than that of the saline group and the TUNEL staining results of the brain tissue section indicated that the TMZ16e-loaded NPs could elevate apoptosis in T98G cells.

Conclusion: In conclusion, the TMZ16e-loaded NPs can be effectively delivered to the brain and targeted to gliomas, exhibiting better anti-glioma activity, indicating they possess great potential in the treatment of drug-resistant glioma.

Fabrication, physicochemical characterization and In vitro anticancer activity of nerolidol encapsulated solid lipid nanoparticles in human colorectal cell line

Nerolidol is a sesquiterpene that occurs naturally and possesses a diverse set of biological characteristics including anticancer activity but has limited solubility, bioavailability, and fast hepatic metabolism. The goal of this study was to develop a nanocarrier system encapsulating a bioactive as well as to evaluate its efficacy in Human Colorectal Cell Line. Solid lipid nanoparticles were fabricated by the emulsion solvent evaporation method and determined the particle size, polydispersity index (PDI), zeta potential, % entrapment efficiency, scanning electron microscopy (SEM), transmission electron microscopy (TEM), drug-excipient interaction study of developed nanoparticles. MTT assay was used to assess the cytotoxicity of formulations in vitro. Nerolidol loaded solid lipid nanoparticles (NR-LNPs) have presented satisfactory properties: mean particles diameter of 159 ± 4.89 nm, PDI of 0.32 ± 0.01, the zeta potential value was found to be -10 ± 1.97 and % entrapment efficiency 71.3% ± 6.11. The formulations demonstrated enhanced biological activity due to enhanced solubility and stability of the bioactive after loading into a nanoformulation along with the better internalization inside the cells.

Physiologically based pharmacokinetic modeling of intravenously administered nanoformulated substances

The use of nanobiomaterials (NBMs) is becoming increasingly popular in the field of medicine. To improve the understanding on the biodistribution of NBMs, the present study aimed to implement and parametrize a physiologically based pharmacokinetic (PBPK) model. This model was used to describe the biodistribution of two NBMs after intravenous administration in rats, namely, poly(alkyl cyanoacrylate) (PACA) loaded with cabazitaxel (PACA-Cbz), and LipImage™ 815. A Bayesian parameter estimation approach was applied to parametrize the PBPK model using the biodistribution data. Parametrization was performed for two distinct dose groups of PACA-Cbz. Furthermore, parametrizations were performed three distinct dose groups of LipImage™ 815, resulting in a total of five different parametrizations. The results of this study indicate that the PBPK model can be adequately parametrized using biodistribution data. The PBPK parameters estimated for PACA-Cbz, specifically the vascular permeability, the partition coefficient, and the renal clearance rate, substantially differed from those of LipImage™ 815. This emphasizes the presence of kinetic differences between the different formulations and substances and the need of tailoring the parametrization of PBPK models to the NBMs of interest. The kinetic parameters estimated in this study may help to establish a foundation for a more comprehensive database on NBM-specific kinetic information, which is a first, necessary step towards predictive biodistribution modeling. This effort should be supported by the development of robust in vitro methods to quantify kinetic parameters.

Recent updates on applications of Lipid-based nanoparticles for site-specific drug delivery

BACKGROUND

Site-specific drug delivery is a widespread and demanding area nowadays. Lipid-based nanoparticulate drug delivery systems have shown promising effects for targeting drugs among lymphatic systems, brain tissues, lungs, and skin. Recently, lipid nanoparticles are used for targeting the brain via the mucosal route for local therapeutic effects. Lipid nanoparticles (LNPs) can help in enhancing the efficacy and lowering the toxicities of anticancer drugs to treat the tumors, particularly in lymph after metastases of tumors. LNPs contain a non-polar core that can improve the absorption of lipophilic drugs into the lymph node and treat tumors. Cellular uptake of drugs can also be enhanced using LNPs and therefore, LNPs are the ideal carrier for treating intracellular infections such as leishmaniasis, tuberculosis and parasitic infection in the brain, etc. Furthermore, specific surface modifications with molecules like mannose, or PEG could improve the macrophage uptake and hence effectively eradicate parasites hiding in macrophages.

METHOD

An electronic literature search was conducted to update the advancements in the field of site-specific drug delivery utilizing lipid-based nanoparticles. A search of the Scopus database (https://www.scopus.com/home.uri) was conducted using the following keywords: lipid-based nanoparticles; site specific delivery.

CONCLUSION

Solid lipid nanoparticles have shown site-specific targeted delivery to various organs including the liver, oral mucosa, brain, epidermis, pulmonary and lymphatic systems. These lipid-based systems showed improved bioavailability as well as reduced side effects. Therefore, the focus of this article is to review the recent research studies on LNPs for site-specific or targeting drug delivery.

Nanocarriers Call the Last Shot in the Treatment of Brain Cancers

Our brain is protected by physio-biological barriers. The blood–brain barrier (BBB) main mechanism of protection relates to the abundance of tight junctions (TJs) and efflux pumps. Although BBB is crucial for healthy brain protection against toxins, it also leads to failure in a devastating disease like brain cancer. Recently, nanocarriers have been shown to pass through the BBB and improve patients’ survival rates, thus becoming promising treatment strategies. Among nanocarriers, inorganic nanocarriers, solid lipid nanoparticles, liposomes, polymers, micelles, and dendrimers have reached clinical trials after delivering promising results in preclinical investigations. The size of these nanocarriers is between 10 and 1000 nm and is modified by surface attachment of proteins, peptides, antibodies, or surfactants. Multiple research groups have reported transcellular entrance as the main mechanism allowing for these nanocarriers to cross BBB. Transport proteins and transcellular lipophilic pathways exist in BBB for small and lipophilic molecules. Nanocarriers cannot enter via the paracellular route, which is limited to water-soluble agents due to the TJs and their small pore size. There are currently several nanocarriers in clinical trials for the treatment of brain cancer. This article reviews challenges as well as fitting attributes of nanocarriers for brain tumor treatment in preclinical and clinical studies.