Lymphatic Uptake of Liposomes after Intraperitoneal Administration Primarily Occurs via the Diaphragmatic Lymphatics and is Dependent on Liposome Surface Properties

Interactions between nanoparticles and lymphatic systems: Mechanisms and applications in drug delivery

The lymphatic system has garnered significant attention in drug delivery research due to the advantages it offers, such as enhancing systemic exposure and enabling lymph node targeting for nanomedicines via the lymphatic delivery route. The journey of drug carriers involves transport from the administration site to the lymphatic vessels, traversing the lymph before entering the bloodstream or targeting specific lymph nodes. However, the anatomical and physiological barriers of the lymphatic system play a pivotal role in influencing the behavior and efficiency of carriers. To expedite research and subsequent clinical translation, this review begins by introducing the composition and classification of the lymphatic system. Subsequently, we explore the routes and mechanisms through which nanoparticles enter lymphatic vessels and lymph nodes. The review further delves into the interactions between nanomedicine and body fluids at the administration site or within lymphatic vessels. Finally, we provide a comprehensive overview of recent advancements in lymphatic delivery systems, addressing the challenges and opportunities inherent in current systems for delivering macromolecules and vaccines.

Vaccine targeting to mucosal lymphoid tissues promotes humoral immunity in the gastrointestinal tract

Viruses, bacteria, and parasites frequently cause infections in the gastrointestinal tract, but traditional vaccination strategies typically elicit little or no mucosal antibody responses. Here, we report a strategy to effectively concentrate immunogens and adjuvants in gut-draining lymph nodes (LNs) to induce gut-associated mucosal immunity. We prepared nanoemulsions (NEs) based on biodegradable oils commonly used as vaccine adjuvants, which encapsulated a potent Toll-like receptor agonist and displayed antigen conjugated to their surface. Following intraperitoneal administration, these NEs accumulated in gut-draining mesenteric LNs, priming strong germinal center responses and promoting B cell class switching to immunoglobulin A (IgA). Optimized NEs elicited 10- to 1000-fold higher antigen-specific IgG and IgA titers in the serum and feces, respectively, compared to free antigen mixed with NE, and strong neutralizing antibody titers against severe acute respiratory syndrome coronavirus 2. Thus, robust gut humoral immunity can be elicited by exploiting the unique lymphatic collection pathways of the gut with a lymph-targeting vaccine formulation.

Biodistribution Analysis of Peptide-Coated Magnetic Iron Nanoparticles: A Simple and Quantitative Method

Biodistribution tracks compounds or molecules of interest in vivo to understand a compound's anticipated efficacy and safety. Nanoparticles deliver nucleic acid and drug payloads and enhance tumor permeability due to multiple properties such as high surface area to volume ratio, surface functionalization, and modifications. Studying the in vivo biodistribution of nanoparticles documents the effectiveness and safety of nanoparticles and facilitates a more application-driven approach for nanoparticle development that allows for more successful translation into clinical use. In this study, we present a relatively simple method to determine the biodistribution of magnetic iron nanoparticles in mice. In vitro, cells take up branched amphiphilic peptide-coated magnetic nanobeads (BAPc-MNBs) like their counterparts, i.e., branched amphiphilic peptide capsules (BAPCs) with a hollow water-filled core. Both BAPc-MNBs and BAPCs have widespread applications as a nanodelivery system. We evaluated the BAPc-MNBs tissue distribution in wild-type mice injected intravenously (i.v.), intraperitoneally (i.p.), or orally gavaged to understand the biological interactions and to further the development of branched amphiphilic peptide-based nanoparticles. The magnetic nanoparticles allowed collection of the BAPc-MNBs from multiple organs by magnetic bead sorting, followed by a high-throughput screening for iron content. When injected i.v., nanoparticles were distributed widely to various organs before elimination from the system via the intestines in feces. The spleen accumulated the highest amount of BAPc-MNBs in mice administered NPs via i.v. and i.p. but not via oral gavage. Taken together, these data demonstrate that the magnetic sorting not only allowed quantification of the BAPc-MNBs but also identified the distribution of BAPc-MNBs after distinct administration methods.

Development of a Supramolecular Hydrogel for Intraperitoneal Injections

Local intraperitoneal drug administration is considered a challenging drug delivery route. The therapeutic efficiency is low, mainly due to rapid clearance of drugs. To increase the intraperitoneal retention time of specific drugs, a pH-sensitive supramolecular hydrogel that can act as a drug delivery vehicle is developed. To establish the optimal formulation of the hydrogel and to study its feasibility, safety, and tissue compatibility, in vitro, postmortem, and in vivo experiments are performed. In vitro tests reveal that a hydrogelator formulation with pH ≥ 9 results in a constant viscosity of 0.1 Pa·s. After administration postmortem, the hydrogel covers the parietal and visceral peritoneum with a thin, soft layer. In the subsequent in vivo experiments, 14 healthy rats are subjected to intraperitoneal injection with the hydrogel. Fourteen and 28 days after implantation, the animals are euthanized. Intraperitoneal exposure to the hydrogel is not resulted in significant weight loss or discomfort. Moreover, no macroscopic adverse effects or signs of organ damage are detected. In several intra-abdominal tissues, vacuolated macrophages are found indicating a physiological degradation of the synthetic hydrogel. This study demonstrates that the supramolecular hydrogel is safe for intraperitoneal application and that the hydrogel shows good tissue compatibility in rats.

Assembly of nanostructured lipid carriers loaded gefitinib and simvastatin as hybrid therapy for metastatic breast cancer: Codelivery and repurposing approach

Breast cancer represents a life-threatening problem globally. The major challenge in the clinical setting is the management of cancer resistance and metastasis. Hybrid therapy can affect several cellular targets involved in carcinogenesis with a lessening of adverse effects. Therefore, the current study aims to assemble, and optimize a hybrid of gefitinib (GFT) and simvastatin (SIM)-loaded nanostructured lipid carrier (GFT/SIM-NLC) to combat metastatic and drug-resistant breast cancer. GFT/SIM-NLC cargos were prepared using design of experiments to investigate the impact of poloxamer-188 and fatty acids concentrations on the physicochemical and pharmaceutical behavior properties of NLC. Additionally, the biosafety of the prepared GFT/SIM-NLC was studied using a fresh blood sample. Afterward, the optimized formulation was subjected to an MTT assay to study the cytotoxic activity of GFT/SIM-NLC compared to free GFT/SIM using an MCF-7 cell line as a surrogate model for breast cancer. The present results revealed that the particle size of the prepared NLC ranged from (209 to 410 nm) with a negative zeta potential value ranging from (-17.2 to -23.9 mV). Moreover, the optimized GFT/SIM-NLC formulation showed favorable physicochemical properties and promising lymphatic delivery cargos. A biosafety study indicates that the prepared NLC has a gentle effect on erythrocyte hemolysis. Cytotoxicity studies revealed that GFT/SIM-NLC enhanced the killing of the MCF-7 cell line compared to free GFT/SIM. This study concluded that the hybrid therapy of GFT/SIM-NLC is a potential approach to combat metastatic and drug-resistant breast cancer.

Biodistribution Analysis of Peptide-Coated Magnetic Iron Nanoparticles: A Simple and Quantitative Method

Biodistribution is the tracking of compounds or molecules of interest in the subject which is integral to understanding their anticipated efficacy and safety. Nanoparticles are highly desirable delivery systems which have the ability to deliver higher nucleic acid and drug payloads and they have enhanced tumor permeability due to their unique properties such as high surface area to volume ratio. Studying the biodistribution of nanoparticles is crucial to understand their effectiveness and safety in vivo, facilitate a more application driven approach for nanoparticle development which will lead to their successful translation into clinical use. In this study, we present a relatively simple method to determine the biodistribution of magnetic iron nanoparticles in mice. Branched Amphiphilic Peptide coated Magnetic Nanobeads BAPc-MNBs like their counterpart i.e., Branched Amphiphilic Peptide capsules (BAPCs) with a hollow water-filled core, are readily taken up by cells in vitro and have widespread application as a nanodelivery systems. We evaluated the BAPc-MNBs tissue distribution in wildtype mice injected intravenously (i.v.), intraperitoneally (i.p.) or orally gavaged to understand the biological interactions of the peptide nanoparticles and to further the development of branched amphiphilic peptides-based nanoparticles. BAPc-MNBs were distributed widely to various organs when injected i.v. and were eliminated from the system via the intestines in feces. The spleen was found to accumulate the highest amount of BAPc-MNBs in mice administered the NPs i.v. and i.p. while they were not absorbed into the system via oral gavage. This study not only presents a relatively simple quantification method to determine in vivo biodistribution of magnetic iron nanoparticles that can be widely applied but also demonstrates the potential of Branched Amphiphilic Peptides in the form of BAPCs or BAPc-MNBs as a delivery system.

Pharmacokinetic evaluation of poorly soluble compounds formulated as nano- or microcrystals after intraperitoneal injection to mice

Intraperitonial (i.p.) delivery during initial stages of drug discovery can allow efficacy readouts for compounds which have suboptimal pharmacokinetics (PK) due to poor physiochemical properties and/or oral bioavailability. A major limitation for widespread use of i.p. administration is the paucity of published data and unclear mechanisms of absorption, particularly when using complex formulations. The aim of the present study was to investigate the PK of poorly soluble compounds with low oral bioavailability when administered i.p. as crystalline nano- and microsuspensions. Three compounds, with varying aqueous solubility (2, 7, and 38 µM, at 37 °C), were dosed to mice at 10 and 50 mg/kg. In vitro dissolution confirmed that nanocrystals dissolved faster than microcrystals and hence were expected to result in higher exposure after i.p. dosing. Surprisingly, the increase in dissolution rate with decrease in particle size did not result in higher in vivo exposure. In contrast, the microcrystals showed higher exposure. The potential of smaller particles to promote access to the lymphatic system is hypothesized and discussed as one plausible explanation. The present work demonstrates the importance of understanding physicochemical properties of drug formulations in the context of the microphysiology at the delivery site and how that knowledge can be leveraged to alter systemic PK.

Ionizable lipid nanoparticles deliver mRNA to pancreatic β cells via macrophage-mediated gene transfer

Systemic messenger RNA (mRNA) delivery to organs outside the liver, spleen, and lungs remains challenging. To overcome this issue, we hypothesized that altering nanoparticle chemistry and administration routes may enable mRNA-induced protein expression outside of the reticuloendothelial system. Here, we describe a strategy for delivering mRNA potently and specifically to the pancreas using lipid nanoparticles. Our results show that delivering lipid nanoparticles containing cationic helper lipids by intraperitoneal administration produces robust and specific protein expression in the pancreas. Most resultant protein expression occurred within insulin-producing β cells. Last, we found that pancreatic mRNA delivery was dependent on horizontal gene transfer by peritoneal macrophage exosome secretion, an underappreciated mechanism that influences the delivery of mRNA lipid nanoparticles. We anticipate that this strategy will enable gene therapies for intractable pancreatic diseases such as diabetes and cancer.

Fluorescent Tracers for In Vivo Imaging of Lymphatic Targets

The lymphatic system continues to gain importance in a range of conditions, and therefore, imaging of lymphatic vessels is becoming more widespread for research, diagnosis, and treatment. Fluorescent lymphatic imaging offers advantages over other methods in that it is affordable, has higher resolution, and does not require radiation exposure. However, because the lymphatic system is a one-way drainage system, the successful delivery of fluorescent tracers to lymphatic vessels represents a unique challenge. Each fluorescent tracer used for lymphatic imaging has distinct characteristics, including size, shape, charge, weight, conjugates, excitation/emission wavelength, stability, and quantum yield. These characteristics in combination with the properties of the target tissue affect the uptake of the dye into lymphatic vessels and the fluorescence quality. Here, we review the characteristics of visible wavelength and near-infrared fluorescent tracers used for in vivo lymphatic imaging and describe the various techniques used to specifically target them to lymphatic vessels for high-quality lymphatic imaging in both clinical and pre-clinical applications. We also discuss potential areas of future research to improve the lymphatic fluorescent tracer design.

Diversifying the skin cancer-fighting worthwhile frontiers: How relevant are the itraconazole/ascorbyl palmitate nanovectors?

Fighting malignant neoplasms via repurposing existing drugs could be a welcome move for prosperous cancer remediations. In the current work, nanovehiculation and optimization of the repositioned itraconazole (ITZ) utilizing ascorbyl palmitate (AP) aspasomes would be an auspicious approach. Further, the optimized aspasomes were incorporated in a cream and tracked for skin deposition. The in vivo efficacy of aspasomal cream on mice subcutaneous Ehrlich carcinoma model was also assessed. The optimized aspasomes revealed nano size (67.83 ± 6.16 nm), negative charge (-79.40 ± 2.23 mV), > 95% ITZ entrapment and high colloidal stability. AP yielded substantial antioxidant capacity and pushed the ITZ cytotoxicity forward against A431 cells (IC₅₀ = 5.3±0.27 μg/mL). An appealing privilege was the aspasomal cream that corroborated spreadability, contemplated skin permeation and potentiated in vivo anticancer competence, reflected in 62.68% reduction in the tumor weight. Such synergistic tumor probes set the foundation for futuristic clinical translation and commercialization.

Effects of particle size and release property of paclitaxel-loaded nanoparticles on their peritoneal retention and therapeutic efficacy against mouse malignant ascites

Malignant ascites accounts for abdominal pain, dyspnea and anorexia, all of which decrease quality of life in cancer patients. Intraperitoneal chemotherapy is a useful method for managing malignant ascites and nanoparticulate drug delivery system makes it more effective by increasing peritoneal retention of anti-cancer drugs. In this study, we prepared paclitaxel-loaded emulsions and liposomes with different particle sizes and drug release properties, and evaluated their peritoneal retention and therapeutic efficacy in Ehrlich's ascites carcinoma (EAC)-bearing mice. Liposomes with the size of 100 nm were rapidly absorbed from peritoneal cavity into blood after intraperitoneal injection into EAC-bearing mice, whereas 1000-nm liposomes were highly retained in peritoneal cavity. Accordingly, 1000 nm liposomes significantly prolonged survival time of EAC-bearing mice but did not inhibit the ascites accumulation because of too poor paclitaxel release. On the other hand, although peritoneal retention of emulsions themselves was similar irrespective of their sizes, 270-nm emulsions showed the higher PTX retention in ascites than other emulsions, and resulted in significantly prolonged survival time and lower accumulation of ascites in EAC-bearing mice. These results indicate that not only particle size but drug release property is one of key determinants of the biodisposition and therapeutic efficacy of intraperitoneally injected nanoparticulate PTX against malignant ascites.

Targeting Lymphatics for Nanoparticle Drug Delivery

The lymphatics transport material from peripheral tissues to lymph nodes, where immune responses are formed, before being transported into systemic circulation. With key roles in transport and fluid homeostasis, lymphatic dysregulation is linked to diseases, including lymphedema. Fluid within the interstitium passes into initial lymphatic vessels where a valve system prevents fluid backflow. Additionally, lymphatic endothelial cells produce key chemokines, such as CCL21, that direct the migration of dendritic cells and lymphocytes. As a result, lymphatics are an attractive delivery route for transporting immune modulatory treatments to lymph nodes where immunotherapies are potentiated in addition to being an alternative method of reaching systemic circulation. In this review, we discuss the physiology of lymphatic vessels and mechanisms used in the transport of materials from peripheral tissues to lymph nodes. We then summarize nanomaterial-based strategies to take advantage of lymphatic transport functions for delivering therapeutics to lymph nodes or systemic circulation. We also describe opportunities for targeting lymphatic endothelial cells to modulate transport and immune functions.

Contrast-enhanced ultrasound in peritoneal dialysis: when and how to perform it

In the field of peritoneal dialysis contrast enhanced ultrasound (CEUS) is a new add-on examination to B-mode ultrasound, but until recently it has never been systematically studied. Based on the experience of the Project Group "Integrated Imaging and Interventional Nephrology" of the Italian Society of Nephrology, CEUS is helpful for evaluating catheter malfunction, peritoneal-pleural communication, leakage, and herniation, and in particular it facilitates dynamic functional imaging of the catheter and its complications. The use of CEUS in peritoneal dialysis is simple, repeatable, safe, radiation-free, and appears to be less time-consuming and more cost-effective than other radiological imaging techniques such as peritoneography, computed tomography, magnetic resonance or peritoneal scintigraphy.

Folate-Targeted Liposomal Formulations Improve Effects of Methotrexate in Murine Collagen-Induced Arthritis

Methotrexate (MTX) is first-line therapy for the treatment of rheumatoid arthritis (RA), however, its use may be limited by side effects notably post-injection malaise. When patients are intolerant or become unresponsive, second-line or antibody therapy may be indicated. A folate-targeted liposomal formulation of MTX (FL-MTX) is tropic to arthritic paws and prevents the onset of collagen-induced arthritis (CIA) in the mouse. We optimized the drug-to-lipid molar ratio to 0.15 and demonstrated the therapeutic efficacy of this form at 2 mg/kg MTX intraperitoneal (i.p.) twice a week. These improved liposomes were present in inflamed joints in proportion to the degree of swelling of the paw and bone remodeling activity. FL-MTX had lower hepatic and renal elimination of MTX than the free substance. FL-MTX provided equivalent results when given i.p. or subcutaneous (s.c.) and FL-MTX 2 mg/kg (drug/lipid 0.15), twice weekly, was similar to or more effective than 35 mg/kg MTX (same route and schedule) in reducing the incidence and swelling in the murine CIA model. These results suggest that FL-MTX is a more potent nanotherapeutic formulation than free MTX treatment. Its potential benefits for patients may include reduced frequency of treatment and lower overall doses for a given response.

Density of Conjugated Antibody Determines the Extent of Fc Receptor Dependent Capture of Nanoparticles by Liver Sinusoidal Endothelial Cells

Despite considerable progress in the design of multifunctionalized nanoparticles (NPs) that selectively target specific cell types, their systemic application often results in unwanted liver accumulation. The exact mechanisms for this general observation are still unclear. Here we asked whether the number of cell-targeting antibodies per NP determines the extent of NP liver accumulation and also addressed the mechanisms by which antibody-coated NPs are retained in the liver. We used polysarcosine-based peptobrushes (PBs), which in an unmodified form remain in the circulation for >24 h due to the absence of a protein corona formation and low unspecific cell binding, and conjugated them with specific average numbers (2, 6, and 12) of antibodies specific for the dendritic cell (DC) surface receptor, DEC205. We assessed the time-dependent biodistribution of PB-antibody conjugates by in vivo imaging and flow cytometry. We observed that PB-antibody conjugates were trapped in the liver and that the extent of liver accumulation strongly increased with the number of attached antibodies. PB-antibody conjugates were selectively captured in the liver via Fc receptors (FcR) on liver sinusoidal endothelial cells, since systemic administration of FcR-blocking agents or the use of F(ab')₂ fragments prevented liver accumulation. Cumulatively, our study demonstrates that liver endothelial cells play a yet scarcely acknowledged role in liver entrapment of antibody-coated NPs and that low antibody numbers on NPs and the use of F(ab')₂ antibody fragments are both sufficient for cell type-specific targeting of secondary lymphoid organs and necessary to minimize unwanted liver accumulation.

Focus on the Lymphatic Route to Optimize Drug Delivery in Cardiovascular Medicine

While oral agents have been the gold standard for cardiovascular disease therapy, the new generation of treatments is switching to other administration options that offer reduced dosing frequency and more efficacy. The lymphatic network is a unidirectional and low-pressure vascular system that is responsible for the absorption of interstitial fluids, molecules, and cells from the peripheral tissue, including the skin and the intestines. Targeting the lymphatic route for drug delivery employing traditional or new technologies and drug formulations is exponentially gaining attention in the quest to avoid the hepatic first-pass effect. The present review will give an overview of the current knowledge on the involvement of the lymphatic vessels in drug delivery in the context of cardiovascular disease.

Intranasal versus intraperitoneal Myrj 59-stabilized cubosomes: A potential armamentarium of effective anti-diabetic therapy

The present study is concerned with the suitability of using Myrj 59, out-performing the commonly used stabilizer i.e., poloxamer, for preparation of cubosomes on one hand and gives an insight into the need for distinctive choice of delivery system and administration route towards better diabetes pharmacotherapy on the other hand. In light, repaglinide (REP) cubosomal dispersion and in-situ gel forms were prepared and physicochemically characterized. The selected cubosomal forms were tested for in-vitro drug release and administered via intranasal (IN) and intraperitoneal (IP) routes and compared with Intravenous (IV) REP solution regarding in-vivo antidiabetic efficacy. The results confirmed the formation of cubic nanostructures (170-233 nm), entrapping high REP amounts (93.2-95.66 %). Sustained REP release from selected cubosomal forms was realized with no burst release. Upon in-vivo assessment, IN and IP REP cubosomes and cubosomal gel exhibited superior long-acting in-vivo traits over IV REP solution, respecting percentages of maximum reduction, total decrease in BG levels, and the pharmacological availability. Moreover, IP REP cubosomes and cubosomal gel revealed higher values of the aforementioned parameters than IN counterparts. In conclusion, IN and IP administration of the newly developed cubosomal forms could proffer feasible options for an optimal control of BG levels.

Lymphatic immunomodulation using engineered drug delivery systems for cancer immunotherapy

Though immunotherapy has revolutionized the treatment of cancer to improve disease outcomes, an array of challenges remain that limit wider clinical success, including low rate of response and immune-related adverse events. Targeting immunomodulatory drugs to therapeutically relevant tissues offers a way to overcome these challenges by potentially enabling enhanced therapeutic efficacy and decreased incidence of side effects. Research highlighting the importance of lymphatic tissues in the response to immunotherapy has increased interest in the application of engineered drug delivery systems (DDSs) to enable specific targeting of immunomodulators to lymphatic tissues and cells that they house. To this end, a variety of DDS platforms have been developed that enable more efficient uptake into lymphatic vessels and lymph nodes to provide targeted modulation of the immune response to cancer. This can occur either by delivery of immunotherapeutics to lymphatics tissues or by direct modulation of the lymphatic vasculature itself due to their direct involvement in tumor immune processes. This review will highlight DDS platforms that, by enabling the activities of cancer vaccines, chemotherapeutics, immune checkpoint blockade (ICB) antibodies, and anti- or pro-lymphangiogenic factors to lymphatic tissues through directed delivery and controlled release, augment cancer immunotherapy.

Lymph-directed immunotherapy - Harnessing endogenous lymphatic distribution pathways for enhanced therapeutic outcomes in cancer

The advent of immunotherapy has revolutionised the treatment of some cancers. Harnessing the immune system to improve tumour cell killing is now standard clinical practice and immunotherapy is the first line of defence for many cancers that historically, were difficult to treat. A unifying concept in cancer immunotherapy is the activation of the immune system to mount an attack on malignant cells, allowing the body to recognise, and in some cases, eliminate cancer. However, in spite of a significant proportion of patients that respond well to treatment, there remains a subset who are non-responders and a number of cancers that cannot be treated with these therapies. These limitations highlight the need for targeted delivery of immunomodulators to both tumours and the effector cells of the immune system, the latter being highly concentrated in the lymphatic system. In this context, macromolecular therapies may provide a significant advantage. Macromolecules are too large to easily access blood capillaries and instead typically exhibit preferential uptake via the lymphatic system. In contexts where immune cells are the therapeutic target, particularly in cancer therapy, this may be advantageous. In this review, we examine in brief the current immunotherapy approaches in cancer and how macromolecular and nanomedicine strategies may improve the therapeutic profiles of these drugs. We subsequently discuss how therapeutics directed either by parenteral or mucosal administration, can be taken up by the lymphatics thereby accessing a larger proportion of the body's immune cells. Finally, we detail drug delivery strategies that have been successfully employed to target the lymphatics.

Berberine-Loaded Liposomes for the Treatment of Leishmania infantum-Infected BALB/c Mice

Berberine (BER)—an anti-inflammatory quaternary isoquinoline alkaloid extracted from plants—has been reported to have a variety of biologic properties, including antileishmanial activity. This work addresses the preparation of BER-loaded liposomes with the aim to prevent its rapid liver metabolism and improve the drug selective delivery to the infected organs in visceral leishmaniasis (VL). BER liposomes (LP-BER) displayed a mean size of 120 nm, negative Z-potential of −38 mV and loaded 6 nmol/μmol lipid. In vitro, the loading of BER in liposomes enhanced its selectivity index more than 7-fold by decreasing its cytotoxicity to macrophages. In mice, LP-BER enhanced drug accumulation in the liver and the spleen. Consequently, the liposomal delivery of the drug reduced parasite burden in the liver and spleen by three and one logarithms (99.2 and 93.5%), whereas the free drug only decreased the infection in the liver by 1-log. The organ drug concentrations—far from IC₅₀ values— indicate that BER immunomodulatory activity or drug metabolites also contribute to the efficacy. Although LP-BER decreased 10-fold—an extremely rapid clearance of the free drug in mice—the value remains very high. Moreover, LP-BER reduced plasma triglycerides levels.

Preclinical evaluation of liposome-supported peritoneal dialysis for the treatment of hyperammonemic crises

Liposome-supported peritoneal dialysis (LSPD) with transmembrane pH-gradient liposomes was previously shown to enhance ammonia removal in cirrhotic rats and holds promise for the treatment of hyperammonemic crises-associated disorders. The main objective of this work was to conduct the preclinical evaluation of LSPD in terms of pharmacokinetics, ammonia uptake, and toxicology to seek regulatory approval for a first-in-human study. The formulation containing citric acid-loaded liposomes was administered intraperitoneally at two different doses once daily for ten days to healthy minipigs. It was also tested in a domestic pig model of hyperammonemia. The pharmacokinetics of citric acid and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine was linear following intraperitoneal administration of medium and high dose. There was no systemic accumulation following daily doses over ten days. The systemic exposure to phospholipids remained low. Furthermore, the liposome-containing peritoneal fluid contained significantly higher ammonia levels than the liposome-free control, demonstrating efficient ammonia sequestration in the peritoneal space. This was indeed confirmed by the ability of LSPD to decrease plasmatic ammonia levels in artificially induced hyperammonemic pigs. LSPD was well tolerated, and no complement activation-related pseudoallergy reactions were observed. The safety profile, the linear pharmacokinetics of citric acid following repeated administrations of LSPD as well as the linear dose-dependent ammonia sequestration in the peritoneal space provide a strong basis for the clinical investigation of LSPD.

Pharmacokinetic and Pharmacodynamic Evaluation of Resveratrol Loaded Cationic Liposomes for Targeting Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. The destructive nature of the disease makes it difficult for clinicians to manage the condition. Hence, there is an urgent need to find new alternatives for HCC, as the role of conventional cytotoxic drugs has reached a plateau to control HCC associated mortality. Antioxidant compounds of plant origin with potential anti-tumor effect have been recognized as alternate modes in cancer treatment and chemoprevention. Resveratrol (RS) is a model natural nonflavonoid drug known for its anti-cancer activity. However, its clinical application is limited due to its poor bioavailability. The current research work aims to formulate, optimize, and characterize RS loaded cationic liposomes (RLs) for specific delivery in HCC. The optimized liposomes formulation (RL5) was spherical with a vesicle size (VS) of 145.78 ± 9.9 nm, ζ potential (ZP) of 38.03 ± 9.12 mV, and encapsulation efficiency (EE) of 78.14 ± 8.04%. In vitro cytotoxicity studies in HepG2 cells demonstrated an improved anti-cancer activity of RL5 in comparison with free RS. These outcomes were supported by a cell uptake study in HepG2 cells, in which RL5 exhibited a higher uptake than free RS. Furthermore, confocal images of HepG2 cells after 3 and 5 h of incubation showed higher internalization of coumarin 6 (C6) loaded liposomes (CL) as compared to those of the free C6. Pharmacokinetic and pharmacodynamic (prophylactic and therapeutic treatment modalities) studies were performed in N-nitrosodiethylamine (NDEA-carcinogen) induced HCC in rats. Pharmacokinetic evaluation of RL5 demonstrated increased localization of RS in cancerous liver tissues by 3.2- and 2.2-fold increase in AUC and Cmax, respectively, when compared to those of the free RS group. A pharmacodynamic investigation revealed a significant reduction in hepatocyte nodules in RL5 treated animals when compared to those of free RS. Further, on treatment with RL5, HCC-bearing rats showed a significant decrease in the liver marker enzymes (alanine transaminase, alkaline phosphatase, aspartate transaminase, total bilirubin levels, γ-glutamyl transpeptidase, and α-fetoprotein), in comparison with that of the disease control group. Our findings were supported by histopathological analysis, and we were first to demonstrate that NDEA induced detrimental effect on rat livers was successfully reversed with the treatment of RL5 formulation. These results implied that delivery of RS loaded cationic liposomes substantially controlled the severity of HCC and that they can be considered as a promising nanocarrier in the management of HCC.

Preclinical Nanomedicines for Polyglutamine-Based Neurodegenerative Diseases

Polyglutamine (polyQ) diseases, such as Huntington's disease and several types of spinocerebellar ataxias, are dominantly inherited progressive neurodegenerative disorders and characterized by the presence of expanded CAG trinucleotide repeats in the respective disease locus of the patient genomes. Patients with polyQ diseases currently need to rely on symptom-relieving treatments because disease-modifying therapeutic interventions remain scarce. Many disease-modifying therapeutic agents are now under clinical testing for treating polyQ diseases, but their delivery to the brain is often too invasive (e.g., intracranial injection) or inefficient, owing to in vivo degradation and clearance by physiological barriers (e.g., oral and intravenous administration). Nanoparticles provide a feasible solution for improving drug delivery to the brain, as evidenced by an increasing number of preclinical studies that document the efficacy of nanomedicines for polyQ diseases over the past 5-6 years. In this review, we present the pathogenic mechanisms of polyQ diseases, the common animal models of polyQ diseases for evaluating the efficacy of nanomedicines, and the common administration routes for delivering nanoparticles to the brain. Next, we summarize the recent preclinical applications of nanomedicines for treating polyQ diseases and improving neurological conditions in vivo, placing emphasis on antisense oligonucleotides, small peptide inhibitors, and small molecules as the disease-modifying agents. We conclude with our perspectives of the burgeoning field of "nanomedicines for polyQ diseases", including the use of inorganic nanoparticles and potential drugs as next-generation nanomedicines, development of higher-order animal models of polyQ diseases, and importance of "brain-nano" interactions.

Pharmacokinetics of Free Oxytetracycline and Oxytetracycline Loaded Cockle Shell Calcium Carbonate-Based Nanoparticle in BALB/c Mice

The development and utilization of nano-antibiotics is currently gaining attention as a possible solution to antibiotic resistance. The aim of this study was therefore to determine the pharmacokinetics of free oxytetracycline (OTC) and oxytetracycline loaded cockle shell calcium carbonate-based nanoparticle (OTC-CNP) after a single dose of intraperitoneal (IP) administration in BALB/c mice. A total of 100 female BALB/c mice divided into two groups of equal number (n = 50) were administered with 10 mg/kg OTC and OTC-CNP, respectively. Blood samples were collected before and post-administration from both groups at time 0, 5, 10, 15, and 30 min and 1, 2, 6, 24, and 48 h, and OTC plasma concentration was quantified using a validated HPLC-UV method. The pharmacokinetic parameters were analyzed using a non-compartment model. The C _max values of OTC in OTC-CNP and free OTC treated group were 64.99 and 23.53 μg/ml, respectively. OTC was detected up to 24 h in the OTC-CNP group as against 1 h in the free OTC group following intraperitoneal administration. In the OTC-CNP group, the plasma elimination rate of OTC was slower while the half-life, the area under the curve, and the volume of the distribution were increased. In conclusion, the pharmacokinetic profile of OTC in the OTC-CNP group differs significantly from that of free OTC. However, further studies are necessary to determine the antibacterial efficacy of OTC-CNP for the treatment of bacterial diseases.

PLGA Nanoparticles for the Intraperitoneal Administration of CBD in the Treatment of Ovarian Cancer: In Vitro and In Ovo Assessment

The intraperitoneal administration of chemotherapeutics has emerged as a potential route in ovarian cancer treatment. Nanoparticles as carriers for these agents could be interesting by increasing the retention of chemotherapeutics within the peritoneal cavity. Moreover, nanoparticles could be internalised by cancer cells and let the drug release near the biological target, which could increase the anticancer efficacy. Cannabidiol (CBD), the main nonpsychotropic cannabinoid, appears as a potential anticancer drug. The aim of this work was to develop polymer nanoparticles as CBD carriers capable of being internalised by ovarian cancer cells. The drug-loaded nanoparticles (CBD-NPs) exhibited a spherical shape, a particle size around 240 nm and a negative zeta potential (-16.6 ± 1.2 mV). The encapsulation efficiency was high, with values above 95%. A controlled CBD release for 96 h was achieved. Nanoparticle internalisation in SKOV-3 epithelial ovarian cancer cells mainly occurred between 2 and 4 h of incubation. CBD antiproliferative activity in ovarian cancer cells was preserved after encapsulation. In fact, CBD-NPs showed a lower IC₅₀ values than CBD in solution. Both CBD in solution and CBD-NPs induced the expression of PARP, indicating the onset of apoptosis. In SKOV-3-derived tumours formed in the chick embryo model, a slightly higher-although not statistically significant-tumour growth inhibition was observed with CBD-NPs compared to CBD in solution. To sum up, poly-lactic-co-glycolic acid (PLGA) nanoparticles could be a good strategy to deliver CBD intraperitoneally for ovarian cancer treatment.