Systematic evaluation of the toxicity and biodistribution of virus mimicking mucus-penetrating DLPC-NPs as oral drug delivery system

Construction of PLGA nanoparticles modified with RWrNM and DLPC and their application in acute rhinosinusitis

In an effort to overcome the nasal mucus barrier and epithelial barrier, as well as reduce entry into the bloodstream, we designed RWrNM and DLPC-modified PLGA nanoparticles (PDR-NPs). These nanoparticles were further encapsulated with dexamethasone acetate (Dexac) to form Dexac/PDR-NPs. Transmission electron microscopy (TEM) analysis revealed their spherical shape with an outer lipid layer. Dynamic light scattering (DLS) determined their particle size to be 125.77 ± 2.01 nm, with a polydispersity index (PDI) of 0.139 ± 0.029. The experimental results demonstrate that DLPC-modified PLGA nanoparticles can effectively reduce interactions with mucin at different concentrations, decrease aggregation, and facilitate their crossing of the mucus barrier. Additionally, results from the cellular uptake assay revealed a significantly greater uptake of PDR-NPs by inflammatory RAW 264.7 cells (2.99-fold higher than that of free C6, p < 0.0001) and inflammatory HUVECs (7.20-fold higher than that of free C6, p < 0.0001). Furthermore, Dexac/PDR-NPs effectively reduced the levels of inflammatory factors nitric oxide (NO) (p < 0.001) and interleukin-6 (IL-6) (p < 0.05) in the supernatant of inflammatory RAW 264.7 cells. Intravital imaging of rats revealed that PDR-NPs had a longer residence time in inflamed nasal tissue compared to PD-NPs. Furthermore, in vivo pharmacodynamic experiments showed that Dexac/PDR-NPs effectively reduced the symptoms of nasal inflammation, lowered the pH of nasal secretions, decreased serum inflammatory factor levels (TNF-α and IL-6), and reduced nasal mucosal inflammatory factor levels (IL-1β), while also reducing the degree of inflammation in the nasal mucosa. Both cytotoxicity assays and in vivo results indicate that PDR-NPs have a good safety profile. PDR-NPs not only overcome the nasal mucus barrier but also reduce the systemic toxicities associated with drug entry into the circulation by enhancing the targeting of inflammatory macrophages and inflammatory vascular endothelial cells. PDR-NPs allow for an "open sources and cut costs" treatment strategy to increase drug retention in the inflamed nasal tissues, reducing toxicity and increasing efficacy. In conclusion, PDR-NPs can be a promising drug delivery system for the local treatment of acute rhinosinusitis.

Recent Advancements in the Development of Nanocarriers for Mucosal Drug Delivery Systems to Control Oral Absorption

Oral administration of active pharmaceutical ingredients is desirable because it is easy, safe, painless, and can be performed by patients, resulting in good medication adherence. The mucus layer in the gastrointestinal (GI) tract generally acts as a barrier to protect the epithelial membrane from foreign substances; however, in the absorption process after oral administration, it can also disturb effective drug absorption by trapping it in the biological sieve structured by mucin, a major component of mucus, and eliminating it by mucus turnover. Recently, functional nanocarriers (NCs) have attracted much attention due to their immense potential and effectiveness in the field of oral drug delivery. Among them, NCs with mucopenetrating and mucoadhesive properties are promising dosage options for controlling drug absorption from the GI tracts. Mucopenetrating and mucoadhesive NCs can rapidly deliver encapsulated drugs to the absorption site and/or prolong the residence time of NCs close to the absorption membrane, providing better medications than conventional approaches. The surface characteristics of NCs are important factors that determine their functionality, owing to the formation of various kinds of interactions between the particle surface and mucosal components. Thus, a deeper understanding of surface modifications on the biopharmaceutical characteristics of NCs is necessary to develop the appropriate mucosal drug delivery systems (mDDS) for the treatment of target diseases. This review summarizes the basic information and functions of the mucosal layer, highlights the recent progress in designing functional NCs for mDDS, and discusses their performance in the GI tract.

Transepithelial transport and cytoprotection of novel antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham

As a traditional fermented meat product, dry-cured Xuanwei ham could be a rich source of bioactive peptides. This study intended to investigate the transepithelial transport and cytoprotection of antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham. Through ultrafiltration and gel filtration chromatography after simulated digestion, five new antioxidative cell-penetrating peptides (CPPs) with 16-27 amino acid residues were identified, and protective effects of the pretreatment with GHYTEGAELVDSVLDVVRK (GK-19) and TDEFQLHTNVNDGTEFGGSIYQK (TK-23) on H₂O₂-induced damaged HepG2 cells were investigated. The results showed that the peptide TK-23 at 0.5 mg mL^-1 showed a good antioxidant activity through upregulating the activity of antioxidant enzymes (CAT, SOD and GR) and decreasing the MDA level in H₂O₂-induced damaged HepG2 cells with a better protective effect compared to GSH. Our observations of novel antioxidant CPPs with 16-27 amino acid residues could enrich the antioxidative CPP database, and these findings could provide data support for further study of CPPs.

Surface design of nanocarriers: Key to more efficient oral drug delivery systems

As nanocarriers (NCs) can improve the solubility of drugs, prevent their degradation by gastrointestinal (GI) enzymes and promote their transport across the mucus gel layer and absorption membrane, the oral bioavailability of these drugs can be substantially enhanced. All these properties of NCs including self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), liposomes, polymeric nanoparticles, inorganic nanoparticles and polymeric micelles depend mainly on their surface chemistry. In particular, interaction with food, digestive enzymes, bile salts and electrolytes, diffusion behaviour across the mucus gel layer and fate on the absorption membrane are determined by their surface. Bioinert surfaces limiting interactions with gastrointestinal fluid and content as well as with mucus, adhesive surfaces providing an intimate contact with the GI mucosa and absorption enhancing surfaces can be designed. Furthermore, charge converting surfaces shifting their zeta potential from negative to positive directly at the absorption membrane and surfaces providing a targeted drug release are advantageous. In addition to these passive surfaces, even active surfaces cleaving mucus glycoproteins on their way through the mucus gel layer can be created. Within this review, we provide an overview on these different surfaces and discuss their impact on the performance of NCs in the GI tract.

Novel carvedilol-loaded pro-phytomicelles: formulation, characterization and enhanced protective efficacy against acetaminophen-inducedliverinjury in mice

The work describes a novel, small-molecule phytochemicals as nanomaterials based pro-micelles (pro-phytomicelles) drug delivery system, for oral delivery of carvedilol (CAR). This novel nanoformulation of CAR, named CAR pro-phytomicelles, was prepared with rebaudioside A (RA) and dipotassium glycyrrhizinate (DG) as mixed nanomaterials. The formulation was optimized, leading to a 502-fold increase in solubility of CAR in water as a result of encapsulation within mixed phytomicelles based on DG and RA. CAR pro-phytomicelles samples could be instantly dissolved into aqueous media to formulate clear phytomicelle solutions with CAR encapsulation efficiency of 99.67 ± 0.02 %, and small micelle size of 15.62 ± 0.27 nm. CAR pro-phytomicelles exhibited good storage stability, rapid in vitro release in simulated intestinal fluid, and improved in vitro antioxidant activity. CAR pro-phytomicelles had good biocompatibility. Protective efficacy evaluation revealed that acetaminophen overdose could induce high mortality and severe liver injury in mice, while CAR pro-phytomicelle treatment exhibited significant protective effect against acetaminophen overdose. This protective efficacy was due to a mechanism that involved the regulation of high-mobility group box 1 and its signaling-related proinflammatory cytokines. These results show that pro-phytomicelles could provide a new concept and promising therapeutics as nanomedicines for improving the activities of CAR against acetaminophen-induced liver injury.

A novel self-nanomicellizing system of empagliflozin for oral treatment of acute pancreatitis: An experimental study

Acute pancreatitis (AP) is a severe inflammatory disorder hampered by a lack of effective drugs in its clinical practice. Empagliflozin (EMP) exhibits potential effects against AP but is limited by poor water-solubility and low bioavailability. Herein, a novel self-nanomicellizing formulation of EMP with phytochemical rebaudioside A (RA) as the nanocarrier (RA-EMP) was fabricated to address these issues. RA-EMP powder could be simply prepared and exhibited excellent storage stability, dramatically improved EMP's apparent solubility, and instantly self-assembled into micelles with high EMP encapsulation efficiency in water. In vivo experimental studies showed that RA-EMP exhibited significantly enhanced oral bioavailability of EMP and dramatically improved therapeutic efficacy against AP. The mechanisms through suppressing the effects of oxidative stress and proinflammatory cytokines were involved in this therapeutic effect. The results demonstrated that RA-EMP could serve as a promising way to enhance the oral bioavailability and strengthen the potential therapeutic efficacy of EMP against AP.

Emerging technologies to increase gastrointestinal transit times of drug delivery systems

Apart from already established technologies to increase gastrointestinal transit times, including devices rapidly increasing in size once they have reached the stomach in order to retard the passage through the pylorus, formulations that float on gastric fluids and mucoadhesive drug delivery systems adhering to the gastrointestinal mucosa, there are new technologies emerging that might be game changing. They include mucus permeating nanocarriers that are able to diffuse deeply into the mucus gel layer of the gastric and intestinal mucosa remaining there for a prolonged time period (i), charge-converting nanocarriers that shift their zeta potential from negative to positive within the mucus gel layer providing strong ionic bonds with anionic mucus glycoproteins (ii) and thiolated nanocarriers and cyclodextrins form even covalent bonds with cysteine-rich subdomains of mucus glycoproteins (iii). Within this review we will provide an overview about these emerging new technologies and will critically discuss their potential and shortcomings.

Development of Optimized Novel Liposome Loaded with 6-gingerol and Assessment of its Therapeutic Activity Against NSCLC In vitro and In vivo Experimental Models

6-Gingerol (Gn) is an active compound derived from ginger which possesses various biological activities. The therapeutic applications of Gn are limited due to its hydrophobic nature. To ease its administration, one of the nano-emulsion methods, liposome was selected to encapsulate Gn. Response Surface Methodology (RSM) was used to optimize liposome ratio. 97.2% entrapment efficiency was achieved at the ratio of 1:20:2 (Drug: Lipid: Cholesterol). The optimized liposome attained size below 200 d nm, spherical shape, negative surface charge and showed sustain release upon physical characterization methods such as FESEM, DLS, Zeta potential, Drug release. The signature FTIR peaks of both free Gn and free liposome (FL) were also observed in Lipo-Gn peak. Lipo-Gn showed significant cytotoxic effect on A549 cells (IC50 160.5 ± 0.74µM/ml) as well as inhibits the cell migration. DAPI staining showed higher apoptotic nuclear morphological change in the cells treated with Lipo-Gn, and also Lipo-Gn increased the apoptotic percentage in A549 as 39.89 and 70.32 for 12 and 24h respectively which were significantly more than free Gn. Moreover, the formulation of Lipo-Gn showed significant cell cycle arrest at the G2/M phase compared with free Gn (28.9 and 34.9% in Free Gn vs. 42.7 and 50.1% in Lipo -Gn for 12 and 24hours respectively). Lipo-Gn have been assessed in NSCLC induced BALB/c mice and showed significantly improved pharmacological properties compared to those of free Gn. Thus, Lipo-Gn may be considered for its widening applications against lung cancer.

Orally administered intelligent self-ablating nanoparticles: a new approach to improve drug cellular uptake and intestinal absorption

Oral drug delivery to treat diabetes is being increasingly researched. The mucus and the epithelial cell layers hinder drug delivery. We designed a self-ablating nanoparticle to achieve smart oral delivery to overcome the gastrointestinal barrier. We used the zwitterionic dilauroyl phosphatidylcholine, which exhibits a high affinity toward Oligopeptide transporter 1, to modify poly(lactic-co-glycolic acid) nanoparticles and load hemagglutinin-2 peptide to facilitate its escape from lysosomes. Nanoparticles exhibit a core–shell structure, the lipid layer is degraded by the lysosomes when the nanoparticles are captured by lysosomes, then the inner core of the nanoparticles gets exposed. The results revealed that the self-ablating nanoparticles exhibited higher encapsulation ability than the self-assembled nanoparticles (77% vs 64%) and with better stability. Quantitative cellular uptake, cellular uptake mechanisms, and trans-monolayer cellular were studied, and the results revealed that the cellular uptake achieved using the self-ablating nanoparticles was higher than self-assembling nanoparticles, and the number of uptake pathways via which the self-ablating nanoparticles functioned were higher than the self-assembling nanoparticles. Intestinal mucus permeation, in vivo intestinal circulation, was studied, and the results revealed that the small self-assembling nanoparticles exhibit a good extent of intestinal uptake in the presence of mucus. In vitro flip-flop, intestinal circulation revealed that the uptake of the self-ablating nanoparticles was 1.20 times higher than the self-assembled nanoparticles. Pharmacokinetic study and the pharmacodynamic study showed that the bioavailability and hypoglycemic effect of self-ablating nanoparticles were better than self-assembled nanoparticles.

Preparation and evaluation of lecithin/zein hybrid nanoparticles for the oral delivery of Panax notoginseng saponins

Panax Notoginseng Saponins (PNS) has been widely used in the prevention and treatment of cardiovascular and cerebrovascular diseases such as myocardial infarction, heart failure and cerebral infarction. However, oral administration of PNS showed low bioavailability because of its instability and poor membrane permeability in the gastrointestinal tract. Here, lipoprotein-inspired hybrid nanoparticles of PNS-Lecithin-Zein (PLZ-NPs) were prepared by using a simple phase separation method, which possessed a core-shell structure, where zein was used as protein part to replace the animal origin protein to increase the resistance to acid and enzymes while lecithin was used as the lipid composition to improve the oral absorption of PNS as well as to increase the drug loading capacity of PNS into the nanocarriers. The results of stability test showed that PLZ-NPs had robust enzymolysis resistance ability for acid and digestive enzymes of gastrointestinal environments. The fluorescent resonance energy transfer (FRET) assay confirmed the ability of LZ-NPs to be intactly absorbed by Caco-2 cell monolayer. Cell transport studies demonstrated that the permeability of PLZ-NPs in Caco-2/HT29-MTX co-culture cell model was 1.5-fold that of PNS. Meanwhile, the single-pass intestinal perfusion assay proved the absorption parameter Peff of PLZ-NPs was 1.75 and 1.80 times higher than that of PNS in the ileum and jejunum, respectively. Finally, the in vivo pharmacokinetic experiment showed that the relative oral bioavailability of PLZ-NPs was 1.71-fold that of free PNS in SD rat. In summary, the employment of the Lecithin/Zein hybrid nanoparticles could be considered as a promising approach for PNS analogues.

Angiopep-2-functionalized nanoparticles enhance transport of protein drugs across intestinal epithelia by self-regulation of targeted receptors

Ligand-modified nanoparticles (NPs) have been widely used in oral drug delivery systems to promote endocytosis on intestinal epithelia. However, their transcytosis across the intestinal epithelia is still limited. Except for complex intracellular trafficking, recycling again from the apical sides into the intestinal lumen of the endocytosed NPs cannot be ignored. In this study, we modified NP surfaces with angiopep-2 (ANG) that targeted the low-density lipoprotein receptor-related protein 1 (LRP-1) expressed on the intestine to increase both the apical endocytosis and basolateral transcytosis of NPs. Notably, our finding revealed that ANG NPs could increase the apical expression and further basolateral redistribution of LRP-1 on Caco-2 cells, thus generating an apical-to-basolateral absorption pattern. Because of the enhanced transcytosis, insulin loaded ANG NPs possessed much stronger absorption efficiency and induced maximal blood glucose reduction to 61.46% in diabetic rats. Self-regulating the distribution of receptors on polarized intestine cells to promote basolateral transcytosis will provide promising insights for the rational design of oral delivery systems of protein/peptide drugs.

Biomedical nanoparticle design: What we can learn from viruses

Viruses are nanomaterials with a number of properties that surpass those of many synthetic nanoparticles (NPs) for biomedical applications. They possess a rigorously ordered structure, come in a variety of shapes, and present unique surface elements, such as spikes. These attributes facilitate propitious biodistribution, the crossing of complex biological barriers and a minutely coordinated interaction with cells. Due to the orchestrated sequence of interactions of their stringently arranged particle corona with cellular surface receptors they effectively identify and infect their host cells with utmost specificity, while evading the immune system at the same time. Furthermore, their efficacy is enhanced by their response to stimuli and the ability to spread from cell to cell. Over the years, great efforts have been made to mimic distinct viral traits to improve biomedical nanomaterial performance. However, a closer look at the literature reveals that no comprehensive evaluation of the benefit of virus-mimetic material design on the targeting efficiency of nanomaterials exists. In this review we, therefore, elucidate the impact that viral properties had on fundamental advances in outfitting nanomaterials with the ability to interact specifically with their target cells. We give a comprehensive overview of the diverse design strategies and identify critical steps on the way to reducing them to practice. More so, we discuss the advantages and future perspectives of a virus-mimetic nanomaterial design and try to elucidate if viral mimicry holds the key for better NP targeting.

Advanced materials for drug delivery across mucosal barriers

Mucus is a viscoelastic gel that traps pathogens and other foreign particles to limit their penetration into the underlying epithelium. Dosage forms containing particle-based drug delivery systems are trapped in mucosal layers and will be removed by mucus turnover. Mucoadhesion avoids premature wash-off and prolongs the residence time of drugs on mucus. Moreover, mucus penetration is essential for molecules to access the underlying epithelial tissues. Various strategies have been investigated to achieve mucoadhesion and mucus penetration of drug carriers. Innovations in materials used for the construction of drug-carrier systems allowed the development of different mucoadhesion and mucus penetration delivery systems. Over the last decade, advances in the field of materials chemistry, with a focus on biocompatibility, have led to the expansion of the pool of materials available for drug delivery applications. The choice of materials in mucosal delivery is generally dependent on the intended therapeutic target and nature of the mucosa at the site of absorption. This review presents an up-to-date account of materials including synthesis, physical and chemical modifications of mucoadhesive materials, nanocarriers, viral mimics used for the construction of mucosal drug delivery systems.

In Vitro and In Vivo Models for Evaluating the Oral Toxicity of Nanomedicines

Toxicity studies for conventional oral drug formulations are standardized and well documented, as required by the guidelines of administrative agencies such as the US Food & Drug Administration (FDA), the European Medicines Agency (EMA) or European Medicines Evaluation Agency (EMEA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). Researchers tend to extrapolate these standardized protocols to evaluate nanoformulations (NFs) because standard nanotoxicity protocols are still lacking in nonclinical studies for testing orally delivered NFs. However, such strategies have generated many inconsistent results because they do not account for the specific physicochemical properties of nanomedicines. Due to their tiny size, accumulated surface charge and tension, sizeable surface-area-to-volume ratio, and high chemical/structural complexity, orally delivered NFs may generate severe topical toxicities to the gastrointestinal tract and metabolic organs, including the liver and kidney. Such toxicities involve immune responses that reflect different mechanisms than those triggered by conventional formulations. Herein, we briefly analyze the potential oral toxicity mechanisms of NFs and describe recently reported in vitro and in vivo models that attempt to address the specific oral toxicity of nanomedicines. We also discuss approaches that may be used to develop nontoxic NFs for oral drug delivery.

Intestine-penetrating, pH-sensitive and double-layered nanoparticles for oral delivery of doxorubicin with reduced toxicity

Herein, CMC-coated double-layered nanoparticles were prepared to induce the oral toxicity of doxorubicin via the intestinal absorption effect.