Delivery of loperamide across the blood-brain barrier with polysorbate 80-coated polybutylcyanoacrylate nanoparticles

Recent Advances in Nanodrug Delivery Systems Production, Efficacy, Safety, and Toxicity

In the last three decades, the development of nanoparticles or nano-formulations as drug delivery systems has emerged as a promising tool to overcome the limitations of conventional delivery, potentially to improve the stability and solubility of active molecules, promote their transport across the biological membranes, and prolong circulation times to increase efficacy of a therapy. Despite several nano-formulations having applications in drug delivery, some issues concerning their safety and toxicity are still debated. This chapter describes the recent available information regarding safety, toxicity, and efficacy of nano-formulations for drug delivery. Several key factors can influence the behavior of nanoparticles in a biological environment, and their evaluation is crucial to design non-toxic and effective nano-formulations. Among them, we have focused our attention on materials and methods for their preparation (including the innovative microfluidic technique), mechanisms of interactions with biological systems, purification of nanoparticles, manufacture impurities, and nano-stability. This chapter places emphasis on the utilization of in silico, in vitro, and in vivo models for the assessment and prediction of toxicity associated with these nano-formulations. Furthermore, the chapter includes specific examples of in vitro and in vivo studies conducted on nanoparticles, illustrating their application in this field.

To see or not to see: In vivo nanocarrier detection methods in the brain and their challenges

Nanoparticles have a great potential to significantly improve the delivery of therapeutics to the brain and may also be equipped with properties to investigate brain function. The brain, being a highly complex organ shielded by selective barriers, requires its own specialized detection system. However, a significant hurdle to achieve these goals is still the identification of individual nanoparticles within the brain with sufficient cellular, subcellular, and temporal resolution. This review aims to provide a comprehensive summary of the current knowledge on detection systems for tracking nanoparticles across the blood-brain barrier and within the brain. We discuss commonly employed in vivo and ex vivo nanoparticle identification and quantification methods, as well as various imaging modalities able to detect nanoparticles in the brain. Advantages and weaknesses of these modalities as well as the biological factors that must be considered when interpreting results obtained through nanotechnologies are summarized. Finally, we critically evaluate the prevailing limitations of existing technologies and explore potential solutions.

ApoE-functionalization of nanoparticles for targeted brain delivery-a feasible method for polyplexes?

The blood-brain barrier (BBB) poses a major obstacle in the treatment of all types of central nervous system (CNS) diseases. Small interfering RNA (siRNA) offers in principle a promising therapeutic approach by downregulating disease-related genes via RNA interference. However, the BBB is a formidable barrier for macromolecules such as nucleic acids. In an effort to develop a brain-targeted strategy for siRNA delivery systems formed by electrostatic interactions with cationic polymers (polyplexes (PXs)), we investigated the suitability of the well-known surfactant-based approach for Apolipoprotein E (ApoE)-functionalization of nanoparticles (NPs). The aim of this present work was to investigate if ApoE coating of siRNA PXs formed with cationic branched 25-kDa poly(ethyleneimine) (b-PEI) and nylon-3 polymers without or after precoating with polysorbate 80 (PS 80) would promote successful delivery across the BBB. We utilized highly hydrophobic NM0.2/CP0.8 nylon-3 polymers to evaluate the effects of hydrophobic cyclopentyl (CP) subunits on ApoE binding efficacy and observed successful ApoE binding with and without PS 80 precoating to the nylon-3 but not the PEI polyplexes. Accordingly, ApoE-coated nylon-3 polyplexes showed significantly increased uptake and gene silencing in U87 glioma cells but no benefit in vivo. In conclusion, further optimization of ApoE-functionalized polyplexes and more sophisticated in vitro models are required to achieve more successful in vitro-in vivo translation in future approaches.

Blood-Nanoparticle Interactions Create a Brain Delivery Superhighway for Doxorubicin

Purpose

This study investigated the brain targeting mechanism of doxorubicin-loaded polybutyl cyanoacrylate (PBCA) nanoparticles, particularly their interactions with the blood-brain barrier (BBB). The BBB protects the brain from drugs in the bloodstream and represents a crucial obstacle in the treatment of brain cancer.

Methods

An advanced computer model analyzed the brain delivery of two distinct formulations, Doxil® and surfactant-coated PBCA nanoparticles. Computational learning was combined with in vitro release and cell interaction studies to comprehend the underlying brain delivery pathways.

Results

Our analysis yielded a surprising discovery regarding the brain delivery mechanism of PBCA nanoparticles. While Doxil® exhibited the expected behavior, accumulating in the brain through extravasation in tumor tissue, PBCA nanoparticles employed a unique and previously uncharacterized mechanism. They underwent cell hitchhiking, resulting in a remarkable more than 1000-fold increase in brain permeation rate compared to Doxil® (2.59 × 10-4 vs 0.32 h-1).

Conclusion

The nonspecific binding to blood cells facilitated and intensified interactions of surfactant-coated PBCA nanoparticles with the vascular endothelium, leading to enhanced transcytosis. Consequently, the significant increase in circulation time in the bloodstream, coupled with improved receptor interactions, contributes to this remarkable uptake of doxorubicin into the brain.

The Use of Lipid-based Nanocarriers to Improve Ovarian Cancer Treatment: An Overview of Recent Developments

Ovarian cancer poses a formidable health challenge for women globally, necessitating innovative therapeutic approaches. This review provides a succinct summary of the current research status on lipid-based nanocarriers in the context of ovarian cancer treatment. Lipid-based nanocarriers, including liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs), offer a promising solution for delivering anticancer drugs with enhanced therapeutic effectiveness and reduced adverse effects. Their versatility in transporting both hydrophobic and hydrophilic medications makes them well-suited for a diverse range of anticancer drugs. Active targeting techniques like ligand-conjugation and surface modifications have been used to reduce off-target effects and achieve tumour-specific medication delivery. The study explores formulation techniques and adjustments meant to enhance drug stability and encapsulation in these nanocarriers. Encouraging results from clinical trials and preclinical investigations underscore the promise of lipid-based nanocarriers in ovarian cancer treatment, providing optimism for improved patient outcomes. Notwithstanding these advancements, challenges related to clearance, long-term stability, and scalable manufacturing persist. Successfully translating lipidbased nanocarriers into clinical practice requires addressing these hurdles. To sum up, lipidbased nanocarriers are a viable strategy to improve the effectiveness of therapy for ovarian cancer. With their more focused medication administration and lower systemic toxicity, they may completely change the way ovarian cancer is treated and increase patient survival rates. Lipidbased nanocarriers need to be further researched and developed to become a therapeutically viable treatment for ovarian cancer.

The role of protein corona on nanodrugs for organ-targeting and its prospects of application

Nowadays, nanodrugs become a hotspot in the high-end medical field. They have the ability to deliver drugs to reach their destination more effectively due to their unique properties and flexible functionalization. However, the fate of nanodrugs in vivo is not the same as those presented in vitro, which indeed influenced their therapeutic efficacy in vivo. When entering the biological organism, nanodrugs will first come into contact with biological fluids and then be covered by some biomacromolecules, especially proteins. The proteins adsorbed on the surface of nanodrugs are known as protein corona (PC), which causes the loss of prospective organ-targeting abilities. Fortunately, the reasonable utilization of PC may determine the organ-targeting efficiency of systemically administered nanodrugs based on the diverse expression of receptors on cells in different organs. In addition, the nanodrugs for local administration targeting diverse lesion sites will also form unique PC, which plays an important role in the therapeutic effect of nanodrugs. This article introduced the formation of PC on the surface of nanodrugs and summarized the recent studies about the roles of diversified proteins adsorbed on nanodrugs and relevant protein for organ-targeting receptor through different administration pathways, which may deepen our understanding of the role that PC played on organ-targeting and improve the therapeutic efficacy of nanodrugs to promote their clinical translation.

Targeting cerebral diseases with enhanced delivery of therapeutic proteins across the blood-brain barrier

INTRODUCTION

Cerebral diseases have been threatening public physical and psychological health in the recent years. With the existence of the blood-brain barrier (BBB), it is particularly hard for therapeutic proteins like peptides, enzymes, antibodies, etc. to enter the central nervous system (CNS) and function in diagnosis and treatment in cerebral diseases. Fortunately, the past decade has witnessed some emerging strategies of delivering macromolecular therapeutic proteins across the BBB.

AREAS COVERED

Based on the structure, functions, and substances transport mechanisms, various enhanced delivery strategies of therapeutic proteins were reviewed, categorized by molecule-mediated delivery strategies, carrier-mediated delivery strategies, and other delivery strategies.

EXPERT OPINION

As for molecule-mediated delivery strategies, development of genetic engineering technology, optimization of protein expression and purification techniques, and mature of quality control systems all help to realize large-scale production of recombinant antibodies, making it possible to apply to the clinical practice. In terms of carrier-mediated delivery strategies and others, although nano-carriers/adeno-associated virus (AAV) are also promising candidates for delivering therapeutic proteins or genes across the BBB, some issues still remain to be further investigated, including safety concerns related to applied materials, large-scale production costs, quality control standards, combination therapies with auxiliary delivery strategies like focused ultrasound, etc.

Polymer-based drug delivery systems under investigation for enzyme replacement and other therapies of lysosomal storage disorders

Lysosomes play a central role in cellular homeostasis and alterations in this compartment associate with many diseases. The most studied example is that of lysosomal storage disorders (LSDs), a group of 60 + maladies due to genetic mutations affecting lysosomal components, mostly enzymes. This leads to aberrant intracellular storage of macromolecules, altering normal cell function and causing multiorgan syndromes, often fatal within the first years of life. Several treatment modalities are available for a dozen LSDs, mostly consisting of enzyme replacement therapy (ERT) strategies. Yet, poor biodistribution to main targets such as the central nervous system, musculoskeletal tissue, and others, as well as generation of blocking antibodies and adverse effects hinder effective LSD treatment. Drug delivery systems are being studied to surmount these obstacles, including polymeric constructs and nanoparticles that constitute the focus of this article. We provide an overview of the formulations being tested, the diseases they aim to treat, and the results observed from respective in vitro and in vivo studies. We also discuss the advantages and disadvantages of these strategies, the remaining gaps of knowledge regarding their performance, and important items to consider for their clinical translation. Overall, polymeric nanoconstructs hold considerable promise to advance treatment for LSDs.

A Computational Study of the Immobilization of New 5-Nitroisatine Derivatives with the Use of C60-Based Functionalized Nanocarriers

Isatin-based compounds are a large group of drugs used as competitive inhibitors of ATP. The 5-nitroisatin derivatives studied in this work are inhibitors of the CDK2 enzyme, which can be used in the development of new anti-cancer therapies. One of the basic activities that often allows for an increase in biological activity while reducing the undesirable effects associated with the toxicity of medicinal substances is immobilization based on carriers. In this work, fifty nanocarriers derived from C60 fullerene, containing a bound phenyl ring on their surfaces, were used in the process of the immobilization of isatin derivatives. Based on flexible docking methods, the binding capacities of the drugs under consideration were determined using a wide range of nanocarriers containing symmetric and asymmetric modifications of the phenyl ring, providing various types of interactions. Based on the data collected for each of the tested drugs, including the binding affinity and the structure and stability of complexes, the best candidates were selected in terms of the type of substituent that modified the nanoparticle and its location. Among the systems with the highest affinity are the dominant complexes created by functionalized fullerenes containing substituents with a symmetrical location, such as R2-R6 and R3-R5. Based on the collected data, nanocarriers with a high potential for immobilization and use in the development of targeted therapies were selected for each of the tested drugs.

Nanoparticle-based drug delivery for the treatment of traumatic brain injury

INTRODUCTION

Traumatic brain injuries (TBIs) impact the breadth of society and remain without any approved pharmacological treatments. Despite successful Phase II clinical trials, the failure of many Phase III clinical trials may be explained by insufficient drug targeting and retention, preventing the proper attainment of an observable dosage threshold. To address this challenge, nanoparticles can be functionalized to protect pharmacological payloads, improve targeted drug delivery to sites of injury, and can be combined with supportive scaffolding to improve secondary outcomes.

AREAS COVERED

This review briefly covers the pathophysiology of TBIs and their subtypes, the current pre-clinical and clinical management strategies, explores the common models of focal, diffuse, and mixed traumatic brain injury employed in experimental animals, and surveys the existing literature on nanoparticles developed to treat TBIs.

EXPERT OPINION

Nanoparticles are well suited to improve secondary outcomes as their multifunctionality and customizability enhance their potential for efficient targeted delivery, payload protection, increased brain penetration, low off-target toxicity, and biocompatibility in both acute and chronic timescales.

Future Treatment of Neuropathic Pain in Spinal Cord Injury: The Challenges of Nanomedicine, Supplements or Opportunities?

Neuropathic pain (NP) is a common chronic condition that severely affects patients with spinal cord injuries (SCI). It impairs the overall quality of life and is considered difficult to treat. Currently, clinical management of NP is often limited to drug therapy, primarily with opioid analgesics that have limited therapeutic efficacy. The persistence and intractability of NP following SCI and the potential health risks associated with opioids necessitate improved treatment approaches. Nanomedicine has gained increasing attention in recent years for its potential to improve therapeutic efficacy while minimizing toxicity by providing sensitive and targeted treatments that overcome the limitations of conventional pain medications. The current perspective begins with a brief discussion of the pathophysiological mechanisms underlying NP and the current pain treatment for SCI. We discuss the most frequently used nanomaterials in pain diagnosis and treatment as well as recent and ongoing efforts to effectively treat pain by proactively mediating pain signals following SCI. Although nanomedicine is a rapidly growing field, its application to NP in SCI is still limited. Therefore, additional work is required to improve the current treatment of NP following SCI.

Fabrication and Assessment of Diosgenin Encapsulated Stearic Acid Solid Lipid Nanoparticles for Its Anticancer and Antidepressant Effects Using in vitro and in vivo Models

Inflammatory cascade plays a pivotal role in the onset and progression of major depressive disorder (MDD) and glioblastoma multiforme (GBM). Therefore, questing natural compounds with anti-inflammatory activity such as diosgenin can act as a double-edged sword targeting cancer and cancer-induced inflammation simultaneously. The blood–brain barrier limits the therapeutic efficiency of the drugs against intracranial pathologies including depression and brain cancers. Encapsulating a drug molecule in lipid nanoparticles can overcome this obstacle. The current study has thus investigated the anticancer and antidepressant effect of Tween 80 (P80) coated stearic acid solid lipid nanoparticles (SLNPs) encapsulating the diosgenin. Physio-chemical characterizations of SLNPs were performed to assess their stability, monodispersity, and entrapment efficiency. In vitro cytotoxic analysis of naked and drug encapsulated SLNPs on U-87 cell line indicated diosgenin IC₅₀ value to be 194.4 μM, while diosgenin encapsulation in nanoparticles slightly decreases the toxicity. Antidepressant effects of encapsulated and non-encapsulated diosgenin were comprehensively evaluated in the concanavalin-A–induced sickness behavior mouse model. Behavior test results indicate that diosgenin and diosgenin encapsulated nanoparticles significantly alleviated anxiety-like and depressive behavior. Diosgenin incorporated SLNPs also improved grooming behavior and social interaction as well as showed normal levels of neutrophils and leukocytes with no toxicity indication. In conclusion, diosgenin and diosgenin encapsulated solid lipid nanoparticles proved successful in decreasing in vitro cancer cell proliferation and improving sickness behavioral phenotype and thus merit further exploration.

Polysorbate-Based Drug Formulations for Brain-Targeted Drug Delivery and Anticancer Therapy

Polysorbates (PSs) are synthetic nonionic surfactants consisting of polyethoxy sorbitan fatty acid esters. PSs have been widely employed as emulsifiers and stabilizers in various drug formulations and food additives. Recently, various PS-based formulations have been developed for safe and efficient drug delivery. This review introduces the general features of PSs and PS-based drug carriers, summarizes recent progress in the development of PS-based drug formulations, and discusses the physicochemical properties, biological safety, P-glycoprotein inhibitory properties, and therapeutic applications of PS-based drug formulations. Additionally, recent advances in brain-targeted drug delivery using PS-based drug formulations have been highlighted. This review will help researchers understand the potential of PSs as effective drug formulation agents.

Polymer-Based Nanotherapeutics for Burn Wounds

Burn wounds are complex and intricate injuries that have become a common cause of trauma leading to significant mortality and morbidity every year. Dressings are applied to burn wounds with the aim of promoting wound healing, preventing burn infection and restoring skin function. The dressing protects the injury and contributes to recovery of dermal and epidermal tissues. Polymer-based nanotherapeutics are increasingly being exploited as burn wound dressings. Natural polymers such as cellulose, chitin, alginate, collagen, gelatin and synthetic polymers like poly (lactic-co-glycolic acid), polycaprolactone, polyethylene glycol, and polyvinyl alcohol are being obtained as nanofibers by nanotechnological approaches like electrospinning and have shown wound healing and re-epithelialization properties. Their biocompatibility, biodegradability, sound mechanical properties and unique structures provide optimal microenvironment for cell proliferation, differentiation, and migration contributing to burn wound healing. The polymeric nanofibers mimic collagen fibers present in extracellular matrix and their high porosity and surface area to volume ratio enable increased interaction and sustained release of therapeutics at the site of thermal injury. This review is an attempt to compile all recent advances in the use of polymer-based nanotherapeutics for burn wounds. The various natural and synthetic polymers used have been discussed comprehensively and approaches being employed have been reported. With immense research effort that is currently being invested in this field and development of proper characterization and regulatory framework, future progress in burn treatment is expected to occur. Moreover, appropriate preclinical and clinical research will provide evidence for the great potential that polymer-based nanotherapeutics hold in the management of burn wounds.

Nanodelivery of traditional Chinese Gingko Biloba extract EGb-761 and bilobalide BN-52021 induces superior neuroprotective effects on pathophysiology of heat stroke

Military personnel often exposed to high summer heat are vulnerable to heat stroke (HS) resulting in abnormal brain function and mental anomalies. There are reasons to believe that leakage of the blood-brain barrier (BBB) due to hyperthermia and development of brain edema could result in brain pathology. Thus, exploration of suitable therapeutic strategies is needed to induce neuroprotection in HS. Extracts of Gingko Biloba (EGb-761) is traditionally used in a variety of mental disorders in Chinese traditional medicine since ages. In this chapter, effects of TiO2 nanowired EGb-761 and BN-52021 delivery to treat brain pathologies in HS is discussed based on our own investigations. We observed that TiO2 nanowired delivery of EGb-761 or TiO2 BN-52021 is able to attenuate more that 80% reduction in the brain pathology in HS as compared to conventional drug delivery. The functional outcome after HS is also significantly improved by nanowired delivery of EGb-761 and BN-52021. These observations are the first to suggest that nanowired delivery of EGb-761 and BN-52021 has superior therapeutic effects in HS not reported earlier. The clinical significance in relation to the military medicine is discussed.

Nanotechnology for Pain Management: Current and Future Therapeutic Interventions

Pain is one of the most common medical conditions and affects more Americans than diabetes, heart disease, and cancer combined. Current pain treatments mainly rely on opioid analgesics and remain unsatisfactory. The life-threatening side effects and addictive properties of opioids demand new therapeutic approaches. Nanomedicine may be able to address these challenges as it allows for sensitive and targeted treatments without some of the burdens associated with current clinical pain therapies. This review discusses the physiology of pain, the current landscape of pain treatment, novel targets for pain treatment, and recent and ongoing efforts to effectively treat pain using nanotechnology-based approaches. We highl ight advances in nanoparticle-based drug delivery to reduce side effects, gene therapy to tackle the source of pain, and nanomaterials-based scavenging to proactively mediate pain signaling.

Solid Lipid Nanoparticles (SLNs): An Advanced Drug Delivery System Targeting Brain through BBB

The blood-brain barrier (BBB) plays a vital role in the protection and maintenance of homeostasis in the brain. In this way, it is an interesting target as an interface for various types of drug delivery, specifically in the context of the treatment of several neuropathological conditions where the therapeutic agents cannot cross the BBB. Drug toxicity and on-target specificity are among some of the limitations associated with current neurotherapeutics. In recent years, advances in nanodrug delivery have enabled the carrier system containing the active therapeutic drug to target the signaling pathways and pathophysiology that are closely linked to central nervous system (CNS) disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), multiple sclerosis (MS), brain tumor, epilepsy, ischemic stroke, and neurodegeneration. At present, among the nano formulations, solid lipid nanoparticles (SLNs) have emerged as a putative drug carrier system that can deliver the active therapeutics (drug-loaded SLNs) across the BBB at the target site of the brain, offering a novel approach with controlled drug delivery, longer circulation time, target specificity, and higher efficacy, and more importantly, reducing toxicity in a biomimetic way. This paper highlights the synthesis and application of SLNs as a novel nontoxic formulation strategy to carry CNS drugs across the BBB to improve the use of therapeutics agents in treating major neurological disorders in future clinics.

Development of Polymeric Nanoparticles for Blood-Brain Barrier Transfer-Strategies and Challenges

Neurological disorders such as Alzheimer's disease, stroke, and brain cancers are difficult to treat with current drugs as their delivery efficacy to the brain is severely hampered by the presence of the blood-brain barrier (BBB). Drug delivery systems have been extensively explored in recent decades aiming to circumvent this barrier. In particular, polymeric nanoparticles have shown enormous potentials owing to their unique properties, such as high tunability, ease of synthesis, and control over drug release profile. However, careful analysis of their performance in effective drug transport across the BBB should be performed using clinically relevant testing models. In this review, polymeric nanoparticle systems for drug delivery to the central nervous system are discussed with an emphasis on the effects of particle size, shape, and surface modifications on BBB penetration. Moreover, the authors critically analyze the current in vitro and in vivo models used to evaluate BBB penetration efficacy, including the latest developments in the BBB-on-a-chip models. Finally, the challenges and future perspectives for the development of polymeric nanoparticles to combat neurological disorders are discussed.

Physical stability and in vivo brain delivery of polymeric ibuprofen nanoparticles fabricated by flash nanoprecipitation

Ibuprofen (IBP), a common non-steroidal anti-inflammatory drug (NSAID) with a log P of 3.51, has been shown to possess potential benefit in the treatment of Alzheimer's disease. However, the bioavailability of IBP to the brain is poor, which can be linked to its extensive binding to plasma proteins in the blood. This study aimed to evaluate the nanoparticle production of IBP by flash nanoprecipitation (FNP) technology, and to determine whether the nanoparticles prepared by FNP could enhance the delivery of IBP into the brain. Polymeric IBP nanoparticles were prepared with poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) diblock copolymer as stabilizer under optimized conditions using a four-stream multi-inlet vortex mixer (MIVM). The optimized nanoparticles displayed a mean particle size of around 50 nm, polydispersity index of around 0.2, drug loading of up to 30% and physical stability of up to 34 days. In-depth surface characterization using zeta potential measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) showed that the surfaces of these nanoparticles were covered with the hydrophilic PEG groups from the diblock copolymer. In vivo brain uptake study of the IBP nanoparticles indicated that the particles, when coated with polysorbate 80, displayed an enhanced brain uptake. However, the extent of brain uptake enhancement appeared limited, possibly due to a rapid release of IBP from the nanoparticles into the blood stream following intravenous administration.

Central nervous system delivery of molecules across the blood-brain barrier

Therapies targeting neurological conditions such as Alzheimer's or Parkinson's diseases are hampered by the presence of the blood-brain barrier (BBB). During the last decades, several approaches have been developed to overcome the BBB, such as the use of nanoparticles (NPs) based on biomaterials, or alternative methods to open the BBB. In this review, we briefly highlight these strategies and the most recent advances in this field. Limitations and advantages of each approach are discussed. Combination of several methods such as functionalized NPs targeting the receptor-mediated transcytosis system with the use of magnetic resonance imaging-guided focused ultrasound (FUS) might be a promising strategy to develop theranostic tools as well as to safely deliver therapeutic molecules, such as drugs, neurotrophic factors or antibodies within the brain parenchyma.

From adsorption to covalent bonding: Apolipoprotein E functionalization of polymeric nanoparticles for drug delivery across the blood-brain barrier

The blood-brain barrier (BBB) is composed of brain endothelial cells, pericytes, and astrocytes, which build a tight cellular barrier. Therapeutic (macro)molecules are not able to transit through the BBB in their free form. This limitation is bypassed by apolipoprotein E (ApoE)-functionalized polymeric nanoparticles (NPs) that are able to transport drugs (e.g. dalargin, loperamide, doxorubicin, nerve growth factor) across the BBB via low density lipoprotein (LDL) receptor mediated transcytosis. Coating with polysorbate 80 or poloxamer 188 facilitates ApoE adsorption onto polymeric NPs enabling recognition by LDL receptors of brain endothelial cells. This effect is even enhanced when NPs are directly coated with ApoE without surfactant anchor. Similarly, covalent coupling of ApoE to NPs that bear reactive groups on their surface leads to significantly improved brain uptake while avoiding the use of surfactants. Several in vitro BBB models using brain endothelial cells or co-cultures with astrocytes/pericytes/glioma cells are described which provide first insights regarding the ability of a drug delivery system to cross this barrier. In vivo models are employed to simulate central nervous system-relevant diseases such as Alzheimer's or Parkinson's disease and cerebral cancer.

Cerebrolysin enhances spinal cord conduction and reduces blood-spinal cord barrier breakdown, edema formation, immediate early gene expression and cord pathology after injury

Spinal cord evoked potentials (SCEP) are good indicators of spinal cord function in health and disease. Disturbances in SCEP amplitudes and latencies during spinal cord monitoring predict spinal cord pathology following trauma. Treatment with neuroprotective agents preserves SCEP and reduces cord pathology after injury. The possibility that cerebrolysin, a balanced composition of neurotrophic factors improves spinal cord conduction, attenuates blood-spinal cord barrier (BSCB) disruption, edema formation, and cord pathology was examined in spinal cord injury (SCI). SCEP is recorded from epidural space over rat spinal cord T9 and T12 segments after peripheral nerves stimulation. SCEP consists of a small positive peak (MPP), followed by a prominent negative peak (MNP) that is stable before SCI. A longitudinal incision (2mm deep and 5mm long) into the right dorsal horn (T10 and T11 segments) resulted in an immediate long-lasting depression of the rostral MNP with an increase in the latencies. Pretreatment with either cerebrolysin (CBL 5mL/kg, i.v. 30min before) alone or TiO₂ nanowired delivery of cerebrolysin (NWCBL 2.5mL/kg, i.v.) prevented the loss of MNP amplitude and even enhanced further from the pre-injury level after SCI without affecting latencies. At 5h, SCI induced edema, BSCB breakdown, and cell injuries were significantly reduced by CBL and NWCBL pretreatment. Interestingly this effect on SCEP and cord pathology was still prominent when the NWCBL was delivered 2min after SCI. Moreover, expressions of c-fos and c-jun genes that are prominent at 5h in untreated SCI are also considerably reduced by CBL and NWCBL treatment. These results are the first to show that CBL and NWCBL enhanced SCEP activity and thwarted the development of cord pathology after SCI. Furthermore, NWCBL in low doses has superior neuroprotective effects on SCEP and cord pathology, not reported earlier. The functional significance and future clinical potential of CBL and NWCBL in SCI are discussed.

Preparation and Evaluation of Recombinant Human Erythropoietin Loaded Tween 80-Albumin Nanoparticle for Traumatic Brain Injury Treatment

OBJECTIVE

Traumatic brain injury (TBI) is a serious health problem with few available treatment options. Rh-erythropoietin (rh-EPO) is a potential therapeutic drug for TBI, but it cannot cross the blood-brain barrier (BBB) directly. In this regard, a novel strategy to deliver rh-EPO for enhanced TBI treatment is via the development of Tween 80 modified albumin nanoparticles using electrostatic spray technology.

METHODS

The rh-EPO loaded Tween 80 modified albumin nanoparticles (rh-EPO-Tw-ABNPs) were prepared by electrostatic spray technology, while the process parameters were optimized via a single factor design. Investigation of physicochemical properties, bioactivity and stability of rh-EPO-Tw-ABNPs was carried out. The in vitro release and biocompatibility with nerve cells were also analyzed. The in vivo brain targeting efficiency, brain edema relieving effect and the expression of aquaporin 4 (AQP4) and glial fibrillary acidic protein (GFAP) in the brain were evaluated in TBI model rats.

RESULTS

The particle size of optimal rh-EPO-Tw-ABNPs was about 438 ± 45 nm, with a zeta potential of -25.42 ± 0.8 mv. The average drug loading ratio of rh-EPO-Tw-ABNPs was 21.3± 3.7 IU/mg with a relative bioactivity of 91.6 ± 4.1%. The in vitro release of rh-EPO from the nanoparticles was rather slow, while neither the blank Tw-ABNPs nor rh-EPO-Tw-ABNPs exhibited toxicity on the microglia cells. Furthermore, in vivo experiments indicated that the rh-EPO-Tw-ABNPs could enhance the distribution of EPO in the brain and relieve brain edema more effectively. Moreover, compared with an rh-EPO injection, the rh-EPO-Tw-ABNPs could increase the AQP4 level but reduced GFAP expression in the brain with more efficiency.

CONCLUSION

The rh-EPO-Tw-ABNPs could enhance the transport of rh-EPO into the brain with superior therapeutic effect for TBI.

Chemotherapy for the Management of Cerebral Metastases

Chemotherapy has played a minor role as adjuvant therapy in treatment of cerebral metastases from solid cancers. The blood-brain barrier and cerebral metastases' considerable machinery of self-preservation have been significant obstacles to delivery and efficacy of chemotherapy. However, several methods intended to surmount these challenges have arisen alongside advent of technology and with the development of targeted molecular therapies. Focused ultrasound and molecular Trojan horses represent two such novel means of increasing permeability of the blood-brain barrier to effector agents. Published data on efficacy of these targeted therapies remain mostly restricted to retrospective studies and phase II prospective clinical trials.

Albumin nanoparticles coated with polysorbate 80 for the targeted delivery of antiepileptic drug levetiracetam into the brain

The aim of the study was to target levetiracetam (LEV) into the brain by albumin nanoparticles. The levetiracetam-loaded albumin nanoparticles (LEV-NPs) were formulated by desolvation. The particle size of LEV-NPs was 153.7 ± 44.8 nm and the zeta potential was - 10.8 mV. The in vitro LEV release, in pH 6.8 phosphate buffer, was determined by dialysis and showed a biphasic pattern of drug release and ranged in between 40.42 ± 2.6% w/w and 63.61 ± 2.12% w/w. The biodistribution study was conducted on male Wistar rats. The LEV was given as i.v. injection in tail vein, and the formulations were the free drug, LEV-NPs, and levetiracetam-loaded albumin nanoparticles further coated with 1% polysorbate 80 (LEV-NPs-PS 80). A significant increase in LEV concentration was achieved in the brain for LEV-NPs-PS 80 when compared with LEV free drug. The LEV concentration achieved in the brain after administering free drug and LEV-NPs-PS 80 was 5.28 ± 1.79 and 18.54 ± 2.38 μg/gm respectively. The LEV-NPs-PS 80 enhanced LEV concentration in the brain by 3.51-fold when compared with the free drug. Graphical abstract.

Dopamine-loaded poly (butyl cyanoacrylate) nanoparticles reverse behavioral deficits in Parkinson’s animal models

Aim: Parkinson's disease (PD) is a neurological disorder resulting from decreased dopamine (DA) secretion in the brain, which reflects impaired motor function. Thus, a drug-delivery system for releasing DA into the brain would be of crucial importance. Materials & methods: We herein examined the in vivo drug efficiency of novel poly-butyl-cyanoacrylate nanoparticles loaded with DA (DA-PBCA NPs). Results & conclusion: The NPs were able to pass through the blood–brain barrier and improve brain structure and function in the PD animal models. Moreover, we found a reduced α-synucleinopathy in the animal model brains after the NPs administration. Thus, the NPs seem to be a reliable DA delivery system for treating PD patients.

Crossing the Blood-Brain Barrier: A Review on Drug Delivery Strategies for Treatment of the Central Nervous System Diseases

Many drugs have been designed to treat diseases of the central nervous system (CNS), especially neurodegenerative diseases. However, the presence of tight junctions at the blood-brain barrier has often compromised the efficiency of drug delivery to target sites in the brain. The principles of drug delivery systems across the blood-brain barrier are dependent on substrate-specific (i.e. protein transport and transcytosis) and non-specific (i.e. transcellular and paracellular) transport pathways, which are crucial factors in attempts to design efficient drug delivery strategies. This review describes how the blood-brain barrier presents the main challenge in delivering drugs to treat brain diseases and discusses the advantages and disadvantages of ongoing neurotherapeutic delivery strategies in overcoming this limitation. In addition, we discuss the application of colloidal carrier systems, particularly nanoparticles, as potential tools for therapy for the CNS diseases.

The Immobilization of Oxindole Derivatives Using New Designed Functionalized C60 Nanomolecules

Indirubin and its analogs such as oxindole derivatives are well known as competitive inhibitors of cyclin-dependent kinase 2 (CDK2) and play an important role in the creation of therapies in many cancer diseases. Recent research, in order to increase efficiency, is aimed at creating targeted therapy, which is often based on the immobilization of drugs on the surface of nanocarriers. In this work, two oxindole derivatives were used to test the binding capabilities of newly in silico designed C60 fullerene derivatives. Seventy functionalized nanostructures were created by the addition of amino acid substituents to the single phenyl ring attached to the fullerene surface. Realized calculations, based on flexible docking methods, allowed for obtaining energetic characteristics and structural aspects of complexes created by nanomolecules with considered ligands. Analysis of obtained complexes shows that symmetric substitution to position R3 and R5 allows obtaining fullerene derivatives exhibiting the highest binding capabilities, while the lowest ones are the effect of asymmetric substitution (R2; R4). Obtained values clearly allowed to select a group of substituents and substitution sites that provide the most stable complexes which can be used to create new nanocarriers for the group of drugs under consideration.

Multifunctional Polymeric Nanoplatforms for Brain Diseases Diagnosis, Therapy and Theranostics

The blood-brain barrier (BBB) acts as a barrier to prevent the central nervous system (CNS) from damage by substances that originate from the blood circulation. The BBB limits drug penetration into the brain and is one of the major clinical obstacles to the treatment of CNS diseases. Nanotechnology-based delivery systems have been tested for overcoming this barrier and releasing related drugs into the brain matrix. In this review, nanoparticles (NPs) from simple to developed delivery systems are discussed for the delivery of a drug to the brain. This review particularly focuses on polymeric nanomaterials that have been used for CNS treatment. Polymeric NPs such as polylactide (PLA), poly (D, L-lactide-co-glycolide) (PLGA), poly (ε-caprolactone) (PCL), poly (alkyl cyanoacrylate) (PACA), human serum albumin (HSA), gelatin, and chitosan are discussed in detail.

How Nanoparticle Physicochemical Parameters Affect Drug Delivery to Cells in the Retina via Systemic Interactions

Minor changes in the composition of poloxamer 188-modified, DEAE-dextran-stabilized (PDD) polybutylcyanoacrylate (PBCA) nanoparticles (NPs), by altering the physicochemical parameters (such as size or surface charge), can substantially influence their delivery kinetics across the blood-retina barrier (BRB) in vivo. We now investigated the physicochemical mechanisms underlying these different behaviors of NP variations at biological barriers and their influence on the cellular and body distribution. Retinal whole mounts from rats injected in vivo with fluorescent PBCA NPs were processed for retina imaging ex vivo to obtain a detailed distribution of NPs with cellular resolution in retinal tissue. In line with previous in vivo imaging results, NPs with a larger size and medium surface charge accumulated more readily in brain tissue, and they could be more easily detected in retinal ganglion cells (RGCs), demonstrating the potential of these NPs for drug delivery into neurons. The biodistribution of the NPs revealed a higher accumulation of small-sized NPs in peripheral organs, which may reduce the passage of these particles into brain tissue via a "steal effect" mechanism. Thus, systemic interactions significantly determine the potential of NPs to deliver markers or drugs to the central nervous system (CNS). In this way, minor changes of NPs' physicochemical parameters can significantly impact their rate of brain/body biodistribution.

A window into the brain: Tools to assess pre-clinical efficacy of biomaterials-based therapies on central nervous system disorders

Therapeutic conveyance into the brain is a cardinal requirement for treatment of diverse central nervous system (CNS) disorders and associated pathophysiology. Effectual shielding of the brain by the blood-brain barrier (BBB) sieves out major proportion of therapeutics with the exception of small lipophilic molecules. Various nano-delivery systems (NDS) provide an effective solution around this obstacle owing to their small size and targeting properties. To date, these systems have been used for several pre-clinical disease models including glioma, neurodegenerative diseases and psychotic disorders. An efficacy screen for these systems involves a test battery designed to probe into the multiple facets of therapeutic delivery. Despite their wide application in redressing various disease targets, the efficacy evaluation strategies for all can be broadly grouped into four modalities, namely: histological, bio-imaging, molecular and behavioural. This review presents a comprehensive insight into all of these modalities along with their strengths and weaknesses as well as perspectives on an ideal design for a panel of tests to screen brain nano-delivery systems.

The Immobilization of Oxindole Derivatives with Use of Cube Rhombellane Homeomorphs

A key aspect of modern drug research is the development of delivery methods that ensure the possibility of implementing targeted therapy for a specific biological target. The use of nanocarriers enables to achieve this objective, also allowing to reduce the toxicity of used substances and often extending their bioavailability. Through the application of docking methods, the possibility of using cube rhombellanes as potential carriers for two oxindole derivatives was analyzed. In the studies, compounds identified as inhibitors of the CDK2 enzyme and a set of nanostructures proposed by the Topo Cluj Group were used. The popular fullerene molecule C60 was used as the reference system. The estimated binding affinities and structures of obtained complexes show that use of functionalized cube rhombellanes containing hydrogen bond donors and acceptors in their external molecular shell significantly increases ligand affinity toward considered nanocariers, compared to classic fullerenes. The presented values also allow to state that an important factor determining the mutual affinity of the tested ligands and nanostructures is the symmetry of the analyzed nanocarriers and its influence on the distribution of binding groups (aromatic systems, donors and acceptors of hydrogen bonds) on the surface of nanoparticles.

Overcoming the Blood-Brain Barrier: The Role of Nanomaterials in Treating Neurological Diseases

Therapies directed toward the central nervous system remain difficult to translate into improved clinical outcomes. This is largely due to the blood-brain barrier (BBB), arguably the most tightly regulated interface in the human body, which routinely excludes most therapeutics. Advances in the engineering of nanomaterials and their application in biomedicine (i.e., nanomedicine) are enabling new strategies that have the potential to help improve our understanding and treatment of neurological diseases. Herein, the various mechanisms by which therapeutics can be delivered to the brain are examined and key challenges facing translation of this research from benchtop to bedside are highlighted. Following a contextual overview of the BBB anatomy and physiology in both healthy and diseased states, relevant therapeutic strategies for bypassing and crossing the BBB are discussed. The focus here is especially on nanomaterial-based drug delivery systems and the potential of these to overcome the biological challenges imposed by the BBB. Finally, disease-targeting strategies and clearance mechanisms are explored. The objective is to provide the diverse range of researchers active in the field (e.g., material scientists, chemists, engineers, neuroscientists, and clinicians) with an easily accessible guide to the key opportunities and challenges currently facing the nanomaterial-mediated treatment of neurological diseases.

Loperamide, pimozide, and STF-62247 trigger autophagy-dependent cell death in glioblastoma cells

Autophagy is a well-described degradation mechanism that promotes cell survival upon nutrient starvation and other forms of cellular stresses. In addition, there is growing evidence showing that autophagy can exert a lethal function via autophagic cell death (ACD). As ACD has been implicated in apoptosis-resistant glioblastoma (GBM), there is a high medical need for identifying novel ACD-inducing drugs. Therefore, we screened a library containing 70 autophagy-inducing compounds to induce ATG5-dependent cell death in human MZ-54 GBM cells. Here, we identified three compounds, i.e. loperamide, pimozide, and STF-62247 that significantly induce cell death in several GBM cell lines compared to CRISPR/Cas9-generated ATG5- or ATG7-deficient cells, pointing to a death-promoting role of autophagy. Further cell death analyses conducted using pharmacological inhibitors revealed that apoptosis, ferroptosis, and necroptosis only play minor roles in loperamide-, pimozide- or STF-62247-induced cell death. Intriguingly, these three compounds induce massive lipidation of the autophagy marker protein LC3B as well as the formation of LC3B puncta, which are characteristic of autophagy. Furthermore, loperamide, pimozide, and STF-62247 enhance the autophagic flux in parental MZ-54 cells, but not in ATG5 or ATG7 knockout (KO) MZ-54 cells. In addition, loperamide- and pimozide-treated cells display a massive formation of autophagosomes and autolysosomes at the ultrastructural level. Finally, stimulation of autophagy by all three compounds is accompanied by dephosphorylation of mammalian target of rapamycin complex 1 (mTORC1), a well-known negative regulator of autophagy. In summary, our results indicate that loperamide, pimozide, and STF-62247 induce ATG5- and ATG7-dependent cell death in GBM cells, which is preceded by a massive induction of autophagy. These findings emphasize the lethal function and potential clinical relevance of hyperactivated autophagy in GBM.

Mechanisms of enhanced antiglioma efficacy of polysorbate 80-modified paclitaxel-loaded PLGA nanoparticles by focused ultrasound

The presence of blood-brain barrier (BBB) greatly limits the availability of drugs and their efficacy against glioma. Focused ultrasound (FUS) can induce transient and local BBB opening for enhanced drug delivery. Here, we developed polysorbate 80-modified paclitaxel-loaded PLGA nanoparticles (PS-80-PTX-NPs, PPNP) and examined the enhanced local delivery into the brain for glioma treatment by combining with FUS. Our result showed PPNP had good stability, fast drug release rate and significant toxicity to glioma cells. Combined with FUS, PPNP showed a stronger BBB permeation efficiency both in the in vitro and in vivo BBB models. Mechanism studies revealed the disrupted tight junction, reduced P-glycoprotein expression and ApoE-dependent PS-80 permeation collectively contribute to the enhanced drug delivery, resulting in significantly stronger antitumour efficacy and longer survival time in the tumour-bearing mice. Our study provided a new strategy to efficiently and locally deliver drugs into the brain to treat glioma.

Incorporation of Levodopa into Biopolymer Coatings Based on Carboxylated Carbon Nanotubes for pH-Dependent Sustained Release Drug Delivery

Four drug delivery systems were formulated by non-covalent functionalization of carboxylated single walled carbon nanotubes using biocompatible polymers as coating agent (i.e., Tween 20, Tween 80, chitosan or polyethylene glycol) for the delivery of levodopa, a drug used in Parkinson’s disease. The chemical interaction between the coating agent and carbon nanotubes-levodopa conjugate was confirmed by Fourier transform infrared (FTIR) and Raman studies. The drug release profiles were revealed to be dependent upon the type of applied coating material and this could be further adjusted to a desired rate to meet different biomedical conditions. In vitro drug release experiments measured using UV-Vis spectrometry demonstrated that the coated conjugates yielded a more prolonged and sustained release pattern compared to the uncoated conjugate. Cytotoxicity of the formulated conjugates was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using normal mouse embryonic fibroblast 3T3 cell line. Compared to the non-coated conjugate, the MTT data indicated that the coating procedure improved the biocompatibility of all systems by 34–41% when the concentration used exceeded 100 μg/mL. In conclusion, the comprehensive results of this study suggest that carbon nanotubes-based drug carrier coated with a suitable biomaterial may possibly be a potential nanoparticle system that could facilitate drug delivery to the brain with tunable physicochemical properties.

Nanopharmaceuticals for wound healing - Lost in translation?

Today, many of the newly developed pharmaceuticals and medical devices take advantage of nanotechnology and with a rising incidence of chronic diseases such as diabetes and cardiovascular disease, the number of patients afflicted globally with non-healing wounds is growing. This has created a requirement for improved therapies and wound care. However, converting the strategies applied in early research into new products is still challenging. Many of them fail to comply with the market requirements. This review discusses the legal and scientific challenges in the design of nanomedicines for wound healing. Are they lost in translation or is there a new generation of therapeutics in the pipeline?

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.

Use of Nanoparticles for Cerebral Cancer

Nanoparticles made of poly(butyl cyanoacrylate) (PBCA) or poly(lactic-co-glycolic acid) (PLGA) coated with polysorbate 80 or poloxamer 188 enable the transport of cytostatics such as doxorubicin across the blood-brain barrier (BBB). Following intravenous injection to rats bearing intracranially the very aggressive glioblastoma 101/8 these particles loaded with doxorubicin significantly increased the survival times and led to a complete tumor remission in 20–40% of the animals. Moreover, these particles considerably reduced the dose-limiting cardiotoxicity and also the testicular toxicity of this drug. The drug transport across the BBB by nanoparticles appears to be due to a receptor-mediated interaction with the brain capillary endothelial cells, which is facilitated by certain plasma apolipoproteins adsorbed by nanoparticles in the blood.

Nanoformulations for Drug Delivery: Safety, Toxicity, and Efficacy

This chapter presents an outline of the recent available information regarding safety, toxicity, and efficacy of nano drug delivery systems. Of particular importance is the evaluation of several key factors to design nontoxic and effective nanoformulations. Among them, we focus on nanostructure materials and synthesis methods, mechanisms of interactions with biological systems, treatment of nanoparticles, manufacture impurities, and nanostability. Emphasis is given to in silico, in vitro, and in vivo models used to assess and predict the toxicity of these new formulations. Additionally, some examples of in vitro and in vivo studies of specific nanoderivatives are also presented in this chapter.

Enhanced transport of plant-produced rabies single-chain antibody-RVG peptide fusion protein across an in cellulo blood-brain barrier device

The biomedical applications of antibody engineering are developing rapidly and have been expanded to plant expression platforms. In this study, we have generated a novel antibody molecule in planta for targeted delivery across the blood-brain barrier (BBB). Rabies virus (RABV) is a neurotropic virus for which there is no effective treatment after entry into the central nervous system. This study investigated the use of a RABV glycoprotein peptide sequence to assist delivery of a rabies neutralizing single-chain antibody (ScFv) across an in cellulo model of human BBB. The 29 amino acid rabies virus peptide (RVG) recognizes the nicotinic acetylcholine receptor (nAchR) at neuromuscular junctions and the BBB. ScFv and ScFv-RVG fusion proteins were produced in Nicotiana benthamiana by transient expression. Both molecules were successfully expressed and purified, but the ScFv expression level was significantly higher than that of ScFv-RVG fusion. Both ScFv and ScFv-RVG fusion molecules had potent neutralization activity against RABVin cellulo. The ScFv-RVG fusion demonstrated increased binding to nAchR and entry into neuronal cells, compared to ScFv alone. Additionally, a human brain endothelial cell line BBB model was used to demonstrate that plant-produced ScFv-RVGP fusion could translocate across the cells. This study indicates that the plant-produced ScFv-RVGP fusion protein was able to cross the in celluloBBB and neutralize RABV.

Topical Loperamide-Encapsulated Liposomal Gel Increases the Severity of Inflammation and Accelerates Disease Progression in the Adjuvant-Induced Model of Experimental Rheumatoid Arthritis

This study evaluates the prophylactic effect of the peripherally-selective mu-opioid receptor agonist, loperamide, administered topically in a liposomal gel formulation on pain, inflammation, and disease progression in the adjuvant-induced model of experimental rheumatoid arthritis in female Lewis rats. In a randomized, blinded and controlled animal trial, AIA rats were divided into six groups consisting of eleven rats per group based on the following treatments: loperamide liposomal gel, free loperamide gel, empty liposomal gel, diclofenac gel (Voltaren®), no treatment, and naive control. Topical formulations were applied daily for a maximum of 17 days-starting from day 0 at the same time as immunization. The time course of the effect of the treatments on antinocieption and inflammation was assessed using a paw pressure analgesiometer and plethysmometer, respectively. Arthritis progression was scored daily using an established scoring protocol. At the end of the study, hind paws were processed for histological analysis. Administration of loperamide liposomal gel daily across the duration of the study produced significant peripheral antinociception as expected; however, increased the severity of inflammation and accelerated arthritis progression. This was indicated by an increase in paw volume, behavioral and observational scoring, and histological analysis compared to the control groups. In particular, histology results showed an increase in pannus formation and synovial inflammation, as well as an upregulation of markers of inflammation and angiogenesis. These findings may have implications for the use of loperamide and other opioids in arthritis and potentially other chronic inflammatory diseases.