Intestinal absorption of insulin nanoparticles: Contribution of M cells

Molecular weight-mediated interaction changes for enhancing structural stability, release behavior and M cells-targeting transport efficacy of starch-based nanoparticles

Molecular weight (Mw) of ligand-mediated nanocarriers plays a pivotal role in their architecture and properties. In this study, self-assembled ovalbumin (OVA)-loaded nanoparticles were meticulously engineered by starch polyelectrolytes with different Mw. Results unveiled that, tailoring Mw of GRGDS pentapeptides-grafted carboxymethyl starch (G-CMS) displayed strong binding-affinity and transport efficiency through microfold cells (M cells) pathway in the simulated intestinal epithelial cell monolayer in which M cells were randomly located in the Caco-2 cells monolayer. Notably, nanoparticles assembled from G-CMS with relatively higher Mw exhibited more compact structures due to the stronger interactions between layers compared to that with relatively lower Mw, which rendered remarkably stable and only 19.01 % in vitro OVA leakage under conditions of the upper gastrointestinal tract. Subsequently, more intact nanoparticles reached M cells after in vitro digestion and exhibited higher transport efficiency through the M cells pathways (apparent permeability: 9.38 × 10-5 cm/s) than Caco-2 cells, attributing to specific- and non-specific binding affinity towards M cells. Therefore, optimal Mw tailoring of starch polyelectrolytes can mediate the molecular interactions among their assembled layers and the interactions with M cells to balance the structural compactness, release and transport efficacy of nanoparticles, holding promise for advancing M cells-targeting oral delivery technologies.

Transepithelial transport of nanoparticles in oral drug delivery: From the perspective of surface and holistic property modulation

Despite the promising prospects of nanoparticles in oral drug delivery, the process of oral administration involves a complex transportation pathway that includes cellular uptake, intracellular trafficking, and exocytosis by intestinal epithelial cells, which are necessary steps for nanoparticles to enter the bloodstream and exert therapeutic effects. Current researchers have identified several crucial factors that regulate the interaction between nanoparticles and intestinal epithelial cells, including surface properties such as ligand modification, surface charge, hydrophilicity/hydrophobicity, intestinal protein corona formation, as well as holistic properties like particle size, shape, and rigidity. Understanding these properties is essential for enhancing transepithelial transport efficiency and designing effective oral drug delivery systems. Therefore, this review provides a comprehensive overview of the surface and holistic properties that influence the transepithelial transport of nanoparticles, elucidating the underlying principles governing their impact on transepithelial transport. The review also outlines the chosen of parameters to be considered for the subsequent design of oral drug delivery systems.

Oral targeted drug delivery to post-gastrointestinal sites

As an essential branch of targeted drug delivery, oral targeted delivery is attracting growing attention in recent years. In addition to site-specific delivery for the treatment of locoregional diseases in the gastrointestinal tract (GIT), oral targeted delivery to remote sites beyond the GIT emerges as a cutting-edge research topic. This review aims to provide an overview of the fundamental concepts and most recent advances in this field. Owing to the physiological barriers existing in the GIT, carrier systems should be transported across the enteric epithelia to target remote sites. Recently, pioneer investigations have validated the transport of intact micro- or nanocarriers across gastrointestinal barriers and subsequently to various distal organs and tissues. The microfold (M) cell pathway is the leading mechanism underlying the oral absorption of particulates, but the contribution of the transcellular and paracellular pathways should not be neglected either. In addition to well-acknowledged physicochemical and biological factors, the formation of a protein corona may also influence the biological fate of carrier systems. Although in an early stage of conceptualization, oral targeted delivery to remote diseases has demonstrated promising potential for the treatment of inflammation, tumors, and diseases inflicting the lymphatic and mononuclear phagocytosis systems.

Intranasal drug delivery: The interaction between nanoparticles and the nose-to-brain pathway

Intranasal delivery provides a direct and non-invasive method for drugs to reach the central nervous system. Nanoparticles play a crucial role as carriers in augmenting the efficacy of brain delivery. However, the interaction between nanoparticles and the nose-to-brain pathway and how the various biopharmaceutical factors affect brain delivery efficacy remains unclear. In this review, we comprehensively summarized the anatomical and physiological characteristics of the nose-to-brain pathway and the obstacles that hinder brain delivery. We then outlined the interaction between nanoparticles and this pathway and reviewed the biomedical applications of various nanoparticulate drug delivery systems for nose-to-brain drug delivery. This review aims at inspiring innovative approaches for enhancing the effectiveness of nose-to-brain drug delivery in the treatment of different brain disorders.

Recent Progress in the Oral Delivery of Therapeutic Peptides and Proteins: Overview of Pharmaceutical Strategies to Overcome Absorption Hurdles

Purpose

Proteins and peptides have secured a place as excellent therapeutic moieties on account of their high selectivity and efficacy. However due to oral absorption limitations, current formulations are mostly delivered parenterally. Oral delivery of peptides and proteins (PPs) can be considered the need of the hour due to the immense benefits of this route. This review aims to critically examine and summarize the innovations and mechanisms involved in oral delivery of peptide and protein drugs.

Methods

Comprehensive literature search was undertaken, spanning the early development to the current state of the art, using online search tools (PubMed, Google Scholar, ScienceDirect and Scopus).

Results

Research in oral delivery of proteins and peptides has a rich history and the development of biologics has encouraged additional research effort in recent decades. Enzyme hydrolysis and inadequate permeation into intestinal mucosa are the major causes that result in limited oral absorption of biologics. Pharmaceutical and technological strategies including use of absorption enhancers, enzyme inhibition, chemical modification (PEGylation, pro-drug approach, peptidomimetics, glycosylation), particulate delivery (polymeric nanoparticles, liposomes, micelles, microspheres), site-specific delivery in the gastrointestinal tract (GIT), membrane transporters, novel approaches (self-nanoemulsifying drug delivery systems, Eligen technology, Peptelligence, self-assembling bubble carrier approach, luminal unfolding microneedle injector, microneedles) and lymphatic targeting, are discussed. Limitations of these strategies and possible innovations for improving oral bioavailability of protein and peptide drugs are discussed.

Conclusion

This review underlines the application of oral route for peptide and protein delivery, which can direct the formulation scientist for better exploitation of this route.

Mechanisms of Nanoparticle Transport across Intestinal Tissue: An Oral Delivery Perspective

Oral drug administration has been a popular choice due to patient compliance and limited clinical resources. Orally delivered drugs must circumvent the harsh gastrointestinal (GI) environment to effectively enter the systemic circulation. The GI tract has a number of structural and physiological barriers that limit drug bioavailability including mucus, the tightly regulated epithelial layer, immune cells, and associated vasculature. Nanoparticles have been used to enhance oral bioavailability of drugs, as they can act as a shield to the harsh GI environment and prevent early degradation while also increasing uptake and transport of drugs across the intestinal epithelium. Evidence suggests that different nanoparticle formulations may be transported via different intracellular mechanisms to cross the intestinal epithelium. Despite the existence of a significant body of work on intestinal transport of nanoparticles, many key questions remain: What causes the poor bioavailability of the oral drugs? What factors contribute to the ability of a nanoparticle to cross different intestinal barriers? Do nanoparticle properties such as size and charge influence the type of endocytic pathways taken? In this Review, we summarize the different components of intestinal barriers and the types of nanoparticles developed for oral delivery. In particular, we focus on the various intracellular pathways used in nanoparticle internalization and nanoparticle or cargo translocation across the epithelium. Understanding the gut barrier, nanoparticle characteristics, and transport pathways may lead to the development of more therapeutically useful nanoparticles as drug carriers.

The crossroad of nanovesicles and oral delivery of insulin

INTRODUCTION

Diabetes mellitus is one of the challenging health problems worldwide. Multiple daily subcutaneous injection of insulin causes poor compliance in patients. Development of efficient oral formulations to improve the quality of life of such patients has been an important goal in pharmaceutical industry. However, due to serious issues such as low bioavailability and instability, it has not been achieved yet.

AREAS COVERED

Due to functional properties of the vesicles and the fact that hepatic-directed vesicles of insulin could reach the clinical phases, we focused on three main vesicular delivery systems for oral delivery of insulin: liposomes, niosomes, and polymersomes. Recent papers were thoroughly discussed to provide a broad overview of such oral delivery systems.

EXPERT OPINION

Although conventional liposomes are unstable in the presence of bile salts, their further modifications such as surface coating could increase their stability in the GI tract. Bilosomes showed good flexibility and stability in GI fluids. Also, niosomes were stable, but they could not induce significant hypoglycemia in animal studies. Although polymersomes were effective, they are expensive and there are some issues about their safety and industrial scale-up. Also, we believe that other modifications such as addition of a targeting agent or surface coating of the vesicles could significantly increase the bioavailability of insulin-loaded vesicles.

IgG functionalized polymeric nanoparticles for oral insulin administration

The oral route is the best way to administer a drug; however, fitting peptide drugs in this route is a major challenge. In insulin cases, less than 0.5% of the administered dose achieves systemic circulation. Oral delivery by nanoparticles can increase insulin permeability across the intestinal epithelium while maintaining its structure and activity until release in the gut. This system can be improved to increase permeability across intestinal cells through active delivery. This study aimed to improve a nanoparticle formulation by promoting functionalization of its surface with immunoglobulin G to increase its absorption by intestinal epithelium. The characterization of formulations showed an adequate size and a good entrapment efficiency. Functionalized nanoparticles led to a desirable increase in insulin release time. Differential scanning calorimetry, infrared spectroscopy and paper chromatography proved the interactions of nanoparticle components. With immunoglobulin G, the nanoparticle size was slightly increased, which did not show aggregate formation. The developed functionalized nanoparticle formulation proved to be adequate to carry insulin and potentially increase its internalization by epithelial gut cells, being a promising alternative to the existing formulations for orally administered low-absorption peptides.

Efficient Treatment of Fish Intestinal Parasites Applying a Membrane-Penetrating Oral Drug Delivery Nanoparticle

Nanodelivery of drugs aims to ensure drug stability in the face of adverse biochemical conditions in the course of administration, concomitant with appropriate pharmacological action provided by delivery at the targeted site. In this study, the application potential of a nanoparticle produced with biopolymers chitosan-N-arginine and alginate as an oral drug delivery material is evaluated. Both macromolecules being weak polyelectrolytes, the nanoparticle presents strong thermodynamic interactions with a biological model membrane consisting of a charged lipid liposome bilayer, leading to membrane disruption and membrane penetration of the nanoparticles in ideal conditions of pH corresponding to the oral route. The powder form of the nanoparticle was obtained by lyophilization and with a high percentage of entrapment of the anthelmintic drug praziquantel. In vivo studies were conducted with oral administration to Corydoras schwartzi fish with high intensity of intestinal parasites infection. The in vivo experiments confirmed the mucoadhesive and revealed membrane-penetrating properties of the nanoparticle by translocating the parasite cyst, which provided target drug release and reduction of over 97% of the fish intestinal parasites. Thus, it was evidenced that the nanoparticle was effective in transporting and releasing the drug to the target, providing an efficient treatment.

Mucoadhesive versus mucopenetrating nanoparticles for oral delivery of insulin

Mucoadhesive and mucopenetrating nanoparticles are commonly designed to improve mucosal drug delivery efficiency. Herein, in order to better understand the contribution of mucoadhesion and mucopenetration in oral delivery of biomacromolecules, insulin-loaded poly (n-butylcyanoacrylate) nanoparticles (Ins/PBCA NPs) with different coating layers, chitosan (CS) or alginate (Alg), were designed and their different absorption enhancing mechanisms were explored. It was demonstrated that both the mucoadhesive (Ins/PBCA/CS) and the mucopenetrating (Ins/PBCA/CS/Alg) nanoparticles showed good stability and similar release profiles in the gastrointestinal fluid, the mucoadhesive nanoparticles presented an enrichment in mucus (70%, 10 min) while most of the mucopenetrating nanoparticles penetrated through the mucus (80%, 10 min). Uptake mechanism studies revealed clathrin- and caveolae-mediated endocytosis were mainly involved in the intestinal transport of mucoadhesive nanoparticles while caveolae-mediated endocytosis and macropinocytosis contributed to the absorption of mucopenetrating nanoparticles, and especially, M cells favored the absorption of mucoadhesive nanoparticles. In vivo studies revealed that the mucopenetrating nanoparticles had a fast onset of action while the mucoadhesive nanoparticles presented a sustained hypoglycemic effect in diabetic rats, and overall no significant difference in pharmacological availability was found between the mucopenetrating (8.80%) and mucoadhesive nanoparticles (8.44%). To sum up, due to the varied absorption mechanism in intestine, the mucoadhesive nanoparticles designed herein had a comparable effect in enhancing oral insulin absorption compared with the mucopenetrating nanoparticles. STATEMENT OF SIGNIFICANCE: In order to improve oral delivery efficiency of insulin, insulin-loaded nanoparticles with opposite properties namely mucoadhesion and mucopenetration have been widely developed to either prolong their residence at the absorption site or improve their penetration across mucus. However, their individual contribution in oral insulin absorption is still unclear. In this paper, insulin-loaded poly (n-butylcyanoacrylate) nanoparticles with both properties were designed via different surface coating and their absorption enhancing mechanisms were explored. It was demonstrated that the mucoadhesive and mucopenetrating nanoparticles showed varied retention and mucus-penetration ability in mucus, with different absorption mechanism in intestine, but no statistical difference in pharmacological availability was found between them. Overall, the present work provides us a guidance for the design of oral nano-delivery system.

Insulin therapy development beyond 100 years

The first insulin preparation capable of consistently lowering blood glucose was developed in 1921. But 100 years later, blood glucose control with insulin in people with diabetes is nearly universally suboptimal, with essentially the same molecule still delivered by the same inappropriate subcutaneous injection route. Bypassing this route with oral administration appears to have become technologically feasible, accelerating over the past 50 years, either with packaged insulin peptides or by chemical insulin mimetics. Some of the problems of prospective unregulated absorption of insulin into the circulation from subcutaneous depots might be overcome with glucose-responsive insulins. Approaches to these problems could be modification of the peptide by adducts, or the use of nanoparticles or insulin patches, which deliver insulin according to glucose concentration. Some attention has been paid to targeting insulin preferentially to different organs, either by molecular engineering of insulin, or with adducts. But all these approaches still have problems in even beginning to match the responsiveness of physiological insulin delivery to metabolic requirements, both prandially and basally. As would be expected, for all these technically complex approaches, many examples of abandoned development can be found. Meanwhile, it is becoming possible to change the duration of action of subcutaneous injected insulin analogues to act even more rapidly for meals, and towards weekly insulin for basal administration. The state of the art of all these approaches, and the barriers to success, are reviewed here.

Lipid-Based Nanocarrier System for the Effective Delivery of Nutraceuticals

Nutraceuticals possess several health benefits and functions; however, most nutraceuticals are prone to degradation in the gastrointestinal environment and have poor bioavailability. Application of a novel carrier system is of increasing importance to overcome obstacles and provide efficient applicability. Lipid-based nanocarriers provide a large surface-to-mass ratio, enhanced intestinal absorption by solubilization in the intestinal milieu, intestinal lymphatic transport, and altering enterocyte-based transport. A critical overview of the current limitation, preparation, and application of lipid-based nanocarriers (liposomes and niosomes) and lipid nanoparticles (SLNs and NLCs) is discussed. Physical and gastrointestinal stability and bioavailability of nanoencapsulated nutraceuticals are considered as well.

Nanoparticulate Drug Delivery Strategies to Address Intestinal Cytochrome P450 CYP3A4 Metabolism towards Personalized Medicine

Drug dosing in clinical practice, which determines optimal efficacy, toxicity or ineffectiveness, is critical to patients' outcomes. However, many orally administered therapeutic drugs are susceptible to biotransformation by a group of important oxidative enzymes, known as cytochrome P450s (CYPs). In particular, CYP3A4 is a low specificity isoenzyme of the CYPs family, which contributes to the metabolism of approximately 50% of all marketed drugs. Induction or inhibition of CYP3A4 activity results in the varied oral bioavailability and unwanted drug-drug, drug-food, and drug-herb interactions. This review explores the need for addressing intestinal CYP3A4 metabolism and investigates the opportunities to incorporate lipid-based oral drug delivery to enable precise dosing. A variety of lipid- and lipid-polymer hybrid-nanoparticles are highlighted to improve drug bioavailability. These drug carriers are designed to target different intestinal regions, including (1) local saturation or inhibition of CYP3A4 activity at duodenum and proximal jejunum; (2) CYP3A4 bypass via lymphatic absorption; (3) pH-responsive drug release or vitamin-B12 targeted cellular uptake in the distal intestine. Exploitation of lipidic nanosystems not only revives drugs removed from clinical practice due to serious drug-drug interactions, but also provide alternative approaches to reduce pharmacokinetic variability.

An update on oral drug delivery via intestinal lymphatic transport

Orally administered drug entities have to survive the harsh gastrointestinal environment, penetrate the enteric epithelia and circumvent hepatic metabolism before reaching the systemic circulation. Whereas the gastrointestinal stability can be well maintained by taking proper measures, hepatic metabolism presents as a formidable barrier to drugs suffering from first-pass metabolism. The pharmaceutical academia and industries are seeking alternative pathways for drug transport to circumvent problems associated with the portal pathway. Intestinal lymphatic transport is emerging as a promising pathway to this end. In this review, we intend to provide an updated overview on the rationale, strategies, factors and applications involved in intestinal lymphatic transport. There are mainly two pathways for peroral lymphatic transport-the chylomicron and the microfold cell pathways. The underlying mechanisms are being unraveled gradually and nowadays witness increasing research input and applications.

Liposomes for oral delivery of protein and peptide-based therapeutics: challenges, formulation strategies, and advances

Throughout the past decade, there has been a rapid growth in the development of protein/peptide-based therapeutics. These therapeutics have found widespread applications in the treatment of cancer, infectious diseases, and other metabolic disorders owing to their several desirable attributes, such as reduced toxicity, diverse biological activities, high specificity, and potency. Most protein/peptide-based drugs are still administered parenterally, and there is an unprecedented demand in the pharmaceutical industry to develop oral delivery routes to increase patient acceptability and convenience. Recent advancements in nanomedicine discoveries have led to the development of several nano and micro-particle-based oral delivery platforms for protein/peptide-based therapeutics and among these, liposomes have emerged as a prominent candidate. Liposomes are spherical vesicles composed of one or more phospholipid bilayers enclosing a core aqueous phase. Their unique amphiphilic nature enables encapsulation of a diverse range of bioactives/drugs including both hydrophobic and hydrophilic compounds for delivery. Against this backdrop, this review provides an overview of the current approaches and challenges associated with the routes and methods of oral administration of protein/peptide-based therapeutics by using liposomes as a potential vehicle. First, the conventional and innovative liposome formation approaches have been discussed along with their applications. Next, the challenges associated with current approaches for oral delivery of protein and peptide-derived therapeutics have been thoroughly addressed. Lastly, we have critically reviewed the potential of liposomes utilization as vehicles for oral delivery of proteins emphasizing the current status and future directions in this area.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the in vivo fate of NPs systems. As the other side of a coin, such interactions can also be used for constructing advanced drug delivery systems. Herein, we aim to provide an insight into the advance and flaws of various NPs-based insulin delivery systems. Particularly, an interesting discussion on nano‒protein interactions and its potentials for developing novel insulin delivery systems is initiated.

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Insulin therapy plays essential roles in treating diabetes.

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Optimizing insulin delivery enhances insulin therapy.

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Nanoparticles are promising systems for delivery of insulin.

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Nano-protein interactions influence the delivery of nanoparticles.

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Nano-protein interactions can be used for advanced delivery of insulin.

Polymers and Nanoparticles for Statin Delivery: Current Use and Future Perspectives in Cardiovascular Disease

Atherosclerosis-related coronary artery disease (CAD) is one of the leading sources of mortality and morbidity in the world. Primary and secondary prevention appear crucial to reduce CAD-related complications. In this scenario, statin treatment was shown to be clinically effective in the reduction of adverse events, but systemic administration provides suboptimal results. As an attempt to improve bioavailability and effectiveness, polymers and nanoparticles for statin delivery were recently investigated. Polymers and nanoparticles can help statin delivery and their effects by increasing oral bioavailability or enhancing target-specific interaction, leading to reduced vascular endothelial dysfunction, reduced intimal hyperplasia, reduced ischemia-reperfusion injury, increased cardiac regeneration, positive remodeling in the extracellular matrix, reduced neointimal growth and increased re-endothelization. Moreover, some innovative aspects described in other cardiovascular fields could be translated into the CAD scenario. Recent preclinical studies are underlining the effect of statins in the stimulation and differentiation of endogenous cardiac stem cells, as well as in targeting of local adverse conditions implicated in atherosclerosis, and statin delivery through poly-lactic-co-glycolic acid (PLGA) appears the most promising aspect of current research to enhance drug activity. The present review intends to summarize the current evidence about polymers and nanoparticles for statin delivery in the field of cardiovascular disease, trying to shed light on this topic and identify new avenues for future studies.

Molecular and cellular cues governing nanomaterial-mucosae interactions: from nanomedicine to nanotoxicology

Mucosal tissues constitute the largest interface between the body and the surrounding environment and they regulate the access of molecules, supramolecular structures, particulate matter, and pathogens into it. All mucosae are characterized by an outer mucus layer that protects the underlying cells from physicochemical, biological and mechanical insults, a mono-layered or stratified epithelium that forms tight junctions and controls the selective transport of solutes across it and associated lymphoid tissues that play a sentinel role. Mucus is a gel-like material comprised mainly of the glycoprotein mucin and water and it displays both hydrophilic and hydrophobic domains, a net negative charge, and high porosity and pore interconnectivity, providing an efficient barrier for the absorption of therapeutic agents. To prolong the residence time, absorption and bioavailability of a broad spectrum of active compounds upon mucosal administration, mucus-penetrating and mucoadhesive particles have been designed by tuning the chemical composition, the size, the density, and the surface properties. The benefits of utilizing nanomaterials that interact intimately with mucosae by different mechanisms in the nanomedicine field have been extensively reported. To ensure the safety of these nanosystems, their compatibility is evaluated in vitro and in vivo in preclinical and clinical trials. Conversely, there is a growing concern about the toxicity of nanomaterials dispersed in air and water effluents that unintentionally come into contact with the airways and the gastrointestinal tract. Thus, deep understanding of the key nanomaterial properties that govern the interplay with mucus and tissues is crucial for the rational design of more efficient drug delivery nanosystems (nanomedicine) and to anticipate the fate and side-effects of nanoparticulate matter upon acute or chronic exposure (nanotoxicology). This review initially overviews the complex structural features of mucosal tissues, including the structure of mucus, the epithelial barrier, the mucosal-associated lymphatic tissues and microbiota. Then, the most relevant investigations attempting to identify and validate the key particle features that govern nanomaterial-mucosa interactions and that are relevant in both nanomedicine and nanotoxicology are discussed in a holistic manner. Finally, the most popular experimental techniques and the incipient use of mathematical and computational models to characterize these interactions are described.

Enhancement of atorvastatin oral bioavailability via encapsulation in polymeric nanoparticles

Despite the fact that atrovastatin (At) is being one of the bestselling statins used to prevent complicated cardiovascular diseases, its low oral bioavailability decreases its clinical relevance. Herein, incorporation of At into ethylcellulose nanoparticles (At-NPs) was executed to test if it would enhance its oral bioavailability. The emulsification-evaporation method was used to prepare the At-NPs. The prepared nanoparticles were characterized by measuring the particle size, zeta potential as well as using FTIR, DSC, and XRD examination. The entrapment efficiency, drug content, and the in vitro release behavior of At-NPs were also examined. The in vivo oral bioavailability of the selected At-NPs formula was tested after being given orally to New Zealand rabbits. The nanoparticles obtained had a high drug content and a distinct spherical shape but with varying sizes. No physical or chemical interactions were detected between At and the nanoparticles as confirmed by FTIR, DSC, and XRD. The in vitro release study of At from the prepared At-NPs has shown nanoparticles size-dependent release behavior. The in vivo oral absorption testing confirmed the bioavailability of the prepared At-NPs to be as follows: (C_max = 940 ng/ml and AUC_0-12 = 8759 ng.h/ml) > Lipitor® (C_max = 635 ng/ml and AUC_0-12 = 4367 ng.h/ml) > At (C_max = 515 ng/ml and AUC_0-12 = 2517 ng.h/ml). These results revealed that the oral formula of At-NPs increases the bioavailability of At 3.87 times. This makes ethylcellulose nanoparticles an esteemed candidate nano-vehicle for At, increasing its bioavailability and thus improving its clinical relevance.

Progress in the Development of Chitosan Based Insulin Delivery Systems: A Systematic Literature Review

Diabetes mellitus is a chronic disease that is considered a worldwide epidemic, and its control is a constant challenge for health systems. Since insulin had its first successful use, scientists have researched to improve the desired effects and reduce side-effects. Over the years, the challenge has been to increase adherence to treatment and improve the quality of life for diabetics by developing an insulin delivery system. This systematic review (SR) analyses experimental articles from 1998 to 2018 related to the development of the chitosan/insulin delivery system (CIDS). Automated support: Start tool was used to perform part of these activities. The search terms “insulin”, “delivery or release system”, and “chitosan” were used to retrieve articles in PubMed, Science Direct, Engineering Village, and HubMed. A total of 55 articles were selected. The overview, phase, model, way of administration, and the efficiency of CIDS were analyzed. According to SR results, most of the articles were published from 2010 onwards, representing 72.7% of the selected papers, and research groups from China publicized 23.6% of the selected articles. According to the SR, 51% of the studies were carried out in vivo and 45% in vitro. Most of the systems were nanoparticle based (54.8%), and oral administration was proposed by 60.0% of the selected articles. Only 36.4% performed loaded capacity and encapsulation efficiency assays, and 24 h (16.4%), 12 h (12.7%), and 6 h (11.0%) were the most frequent insulin release times. Chitosan’s intrinsic characteristics, which include biodegradability, biocompatibility, adhesiveness, the ability to open epithelial tight junctions to allow an increase in the paracellular transport of macromolecular drugs, such as insulin, and the fact that it does not result in allergic reactions in the human body after implantation, injection, topical application or ingestion, have contributed to the increase in research of CIDS over the years. However, the number of studies is still limited and the use of an alternative form of insulin administration is not yet possible. Thus, more studies in this area, aiming for the development of an insulin delivery system that can promote more adherence to the treatment and patient comfort, are required.

Recent Progress of Chitosan and Chitosan Derivatives-Based Nanoparticles: Pharmaceutical Perspectives of Oral Insulin Delivery

Diabetes mellitus is a chronic endocrine disease, affecting more than 400 million people around the world. Patients with poorly controlled blood glucose levels are liable to suffer from life-threatening complications, such as cardiovascular, neuropathy, retinopathy and even premature death. Today, subcutaneous parenteral is still the most common route for insulin therapy. Oral insulin administration is favourable and convenient to the patients. In contrast to injection route, oral insulin delivery mimics the physiological pathway of endogenous insulin secretion. However, oral insulin has poor bioavailability (less than 2%) due to the harsh physiological environment through the gastrointestinal tract (GIT). Over the last few decades, many attempts have been made to achieve an effective oral insulin formulation with high bioavailability using insulin encapsulation into nanoparticles as advanced technology. Various natural polymers have been employed to fabricate nanoparticles as a delivery vehicle for insulin oral administration. Chitosan, a natural polymer, is extensively studied due to the attractive properties, such as biodegradability, biocompatibility, bioactivity, nontoxicity and polycationic nature. Numerous studies were conducted to evaluate chitosan and chitosan derivatives-based nanoparticles capabilities for oral insulin delivery. This review highlights strategies that have been applied in the recent five years to fabricate chitosan/chitosan derivatives-based nanoparticles for oral insulin delivery. A summary of the barriers hurdle insulin absorption rendering its low bioavailability such as physical, chemical and enzymatic barriers are highlighted with an emphasis on the most common methods of chitosan nanoparticles preparation. Nanocarriers are able to improve the absorption of insulin through GIT, deliver insulin to the blood circulation and lower blood glucose levels. In spite of some drawbacks encountered in this technology, chitosan and chitosan derivatives-based nanoparticles are greatly promising entities for oral insulin delivery.

Nano and microscale delivery platforms for enhanced oral peptide/protein bioavailability

In recent years, peptide/protein drugs have attracted considerable attention owing to their superior targeting and therapeutic effect and fewer side effects compared with chemical drugs. Oral administration modality with enhanced patient compliance is increasingly being recognized as an ideal route for peptide/protein delivery. However, the limited permeation efficiency and low oral bioavailability of peptide/protein drugs significantly hinder therapeutic advances. To address these problems, various nano and microscale delivery platforms have been developed, which offer significant advantages in oral peptide/protein delivery. In this review, we briefly introduce the transport mechanisms of oral peptide/protein delivery and the primary barriers to this delivery process. We also highlight the recent advances in various nano and microscale delivery platforms designed for oral peptide/protein delivery. We then summarize the existing strategies used in these delivery platforms to improve the oral bioavailability and permeation efficiency of peptide/protein therapeutics. Finally, we discuss the major challenges faced when nano and microscale systems are used for oral peptide/protein delivery. This review is expected to provide critical insight into the design and development of oral peptide/protein delivery systems with significant therapeutic advances.

Liposomes for Enhanced Bioavailability of Water-Insoluble Drugs: In Vivo Evidence and Recent Approaches

It has been known that a considerable number of drugs in clinical use or under development are water-insoluble drugs with poor bioavailability (BA). The liposomal delivery system has drawn attention as one of the noteworthy approaches to increase dissolution and subsequently absorption in the gastrointestinal (GI) tract because of its biocompatibility and ability to encapsulate hydrophobic molecules in the lipid domain. However, there have been several drawbacks, such as structural instability in the GI tract and poor permeability across intestinal epithelia because of its relatively large size. In addition, there have been no liposomal formulations approved for oral use to date, despite the success of parenteral liposomes. Nevertheless, liposomal oral delivery has resurged with the rapid increase of published studies in the last decade. However, it is discouraging that most of this research has been in vitro studies only and there have not been many water-insoluble drugs with in vivo data. The present review focused on the in vivo evidence for the improved BA of water-insoluble drugs using liposomes to resolve doubts raised concerning liposomal oral delivery and attempted to provide insight by highlighting the approaches used for in vivo achievements.

Nanoformulation strategies for improving intestinal permeability of drugs: A more precise look at permeability assessment methods and pharmacokinetic properties changes

The therapeutic efficacy of orally administered drugs is often restricted by their inherent limited oral bioavailability. Low water solubility, limited permeability through the intestinal barrier, instability in harsh environment of the gastrointestinal (GI) tract and being substrate of the efflux pumps and the cytochrome P450 (CYP) can impair oral drug bioavailability resulting in erratic and variable plasma drug profile. As more drugs with low membrane permeability are developed, new interest is growing to enhance their intestinal permeability and bioavailability. A wide variety of nanosystems have been developed to improve drug transport and absorption. Sufficient evidence exists to suggest that nanoparticles are able to increase the transepithelial transport of drug molecules. However, key questions remained unanswered. What types of nanoparticles are more efficient? What are preclinical (or clinical) achievements of each type of nanoformulation in terms of pharmacokinetic (PK) parameters? Addressing this issue in this paper, we have reviewed the current literature regarding permeability enhancement, permeability assessment methods and changes in PK parameters following administration of various nanoformulations. Although permeability enhancement by various nanoformulations holds great promise for oral drug delivery, many challenges still need to be addressed before development of more clinically successful nanoproducts.

Anionic nanoparticles enable the oral delivery of proteins by enhancing intestinal permeability

The oral delivery of bioactive peptides and proteins is prevented by the intestinal epithelial barrier, in which intercellular tight junction complexes block the uptake of macromolecules. Here we show that anionic nanoparticles induce tight junction relaxation, increasing intestinal permeability and enabling the oral delivery of proteins. This permeation-enhancing effect is a function of nanoparticle size and charge, with smaller (≤ 200 nm) and more negative particles (such as silica) conferring enhanced permeability. In healthy mice, silica nanoparticles enabled the oral delivery of insulin and exenatide, with 10 U kg-1 orally delivered insulin sustaining hypoglycaemia for a few hours longer than a 1 U kg-1 dose of subcutaneously injected insulin. In healthy, hyperglycaemic and diabetic mice, the oral delivery of 10 U kg-1 insulin led to a dose-adjusted bioactivity of, respectively, 35%, 29% and 23% that of the subcutaneous injection of 1 U kg-1 insulin. The permeation-enhancing effect of the nanoparticles was reversible, non-toxic, and attributable to the binding to integrins on the surface of epithelial cells.

Adapting liposomes for oral drug delivery

Liposomes mimic natural cell membranes and have long been investigated as drug carriers due to excellent entrapment capacity, biocompatibility and safety. Despite the success of parenteral liposomes, oral delivery of liposomes is impeded by various barriers such as instability in the gastrointestinal tract, difficulties in crossing biomembranes, and mass production problems. By modulating the compositions of the lipid bilayers and adding polymers or ligands, both the stability and permeability of liposomes can be greatly improved for oral drug delivery. This review provides an overview of the challenges and current approaches toward the oral delivery of liposomes.

Solvent-free synthesis of acetylated cashew gum for oral delivery system of insulin

Cashew gum (CG) is a biopolymer that presents a favorable chemical environment for structural modifications, which leads to more stable and resistant colloidal systems. The gum was subjected to an acetylation reaction using a fast, simple, solvent-free and low cost methodology. The derivative was characterized by infrared and NMR spectroscopy, elemental analysis, coefficient of solubility and zeta potential. The modified biopolymer was used as a platform for drug delivery systems using insulin as a model drug. Nanoparticles were developed through the technique of polyelectrolytic complexation and were characterized by size, surface charge, entrapment efficiency and gastrointestinal release profile. The nanoparticles presented size of 460 nm with a 52.5% efficiency of entrapment of insulin and the electrostatic stabilization was suggested by the zeta potential of + 30.6 mV. Sustained release of insulin was observed for up to 24 h. The results showed that acetylated cashew gum (ACG) presented potential as a vehicle for sustained oral insulin release.

Exploring Peyer's Patch Uptake as a Strategy for Targeted Lung Delivery of Polymeric Rifampicin Nanoparticles

Uptake of nanoparticles through Peyer's Patches following oral administration could enable translocation through lymph to lymphatic organs like the lungs. An important consideration, however, is nanosize and particle hydrophobicity. Furthermore, as delivering the nanoparticles to the intestine where the Peyer's Patches are localized is important, their intact and rapid transit through the stomach into the intestine is highly desirable. We report hydrophobization of mucoadhesive Rifampicin-GantrezAN-119 nanoparticles (GzNP) using a hydrophobic polymer, ethyl cellulose (EC), with the objectives of augmenting Peyer's Patch uptake due to enhanced hydrophobicity and increased intestinal localization as a result of decreased mucoadhesion. RIF-Gantrez-EC nanoparticles (ECGzNP2) exhibited >13% RIF loading and an average particle size of 400-450 nm, which is appropriate for translation through lymph following Peyer's Patch uptake. Higher contact angle (67.3 ± 3.5° vs 30.3 ± 2.1°) and lower mucoadhesion (30.7 ± 4.8 g vs 87.0 ± 3.0 g) of ECGzNP2 over GzNP confirmed hydrophobization and lower mucoadhesion. Fluorescence photomicrographs of intraduodenally administered coumarin-labeled RIF-NP in rats demonstrated higher Peyer's Patch uptake with ECGzNP2, while the increased lung/plasma RIF ratio signified lymph mediated lung targeting. The gastrointestinal transit study in rats, which revealed a significantly higher intestine-to-stomach accumulation ratio with ECGzNP2 (3.4) compared to GzNP (1.0) [ p < 0.05], confirmed availability of the NP in the intestine for Peyer's Patch uptake. Such uptake enabled 182.4 ± 22.6% increase in relative bioavailability, a ∼2-fold higher plasma AUC/MIC ratio and significantly higher lung concentration with ECGzNP2, thereby proposing better efficacy. A significantly higher lung/liver ratio with ECGzNP2 also suggested lower hepatic exposure. The repeated dose 28-day oral toxicity study demonstrated the safety of the nanocarrier and reduced hepatotoxicity with ECGzNP2 compared to RIF. We hereby demonstrate uptake of orally administered NP through Peyer's Patches as a feasible strategy for lung targeting.

Strategies for the enhanced intracellular delivery of nanomaterials

The intracellular delivery of nanomaterials and drugs has been attracting increasing research interest, mainly because of their important effects and functions in several organelles. Targeting specific organelles can help treat or decrease the symptoms of diabetes, cancer, infectious, and autoimmune diseases. Tuning biological and chemical properties enables the creation of functionalized nanomaterials with enhanced intracellular uptake, ability to escape premature lysosome degradation, and to reach a specific target. Here, we provide an update of recent advances in the intracellular delivery mechanisms that could help drugs reach their target more efficiently.

Biomimetic thiamine- and niacin-decorated liposomes for enhanced oral delivery of insulin

Biomimetic nanocarriers are emerging as efficient vehicles to facilitate dietary absorption of biomacromolecules. In this study, two vitamins, thiamine and niacin, are employed to decorate liposomes loaded with insulin, thus facilitating oral absorption via vitamin ligand-receptor interactions. Both vitamins are conjugated with stearamine, which works to anchor the ligands to the surface of liposomes. Liposomes prepared under optimum conditions have a mean particle size of 125-150 nm and an insulin entrapment efficiency of approximately 30%-36%. Encapsulation into liposomes helps to stabilize insulin due to improved resistance against enzymatic disruption, with 60% and 80% of the insulin left after 4 h when incubated in simulated gastric and intestinal fluids, respectively, whereas non-encapsulated insulin is broken down completely at 0.5 h. Preservation of insulin bioactivity against preparative stresses is validated by intra-peritoneal injection of insulin after release from various liposomes using the surfactant Triton X-100. In a diabetic rat model chemically induced by streptozotocin, both thiamine- and niacin-decorated liposomes showed a comparable and sustained mild hypoglycemic effect. The superiority of decorated liposomes over conventional liposomes highlights the contribution of vitamin ligands. It is concluded that decoration of liposomes with thiamine or niacin facilitates interactions with gastrointestinal vitamin receptors and thereby facilitates oral absorption of insulin-loaded liposomes.

Binary and Tertiary Complex Based on Short-Chain Glucan and Proanthocyanidins for Oral Insulin Delivery

The present study was performed to investigate binary and tertiary nanocomposites between short-chain glucan (SCG) and proanthocyanidins (PAC) for the oral delivery of insulin. There was a large decrease in fluorescence intensity of insulin in the presence of SCG or the combination of SCG with PAC. Fourier transform infrared spectroscopy revealed that the binary and tertiary nanocomposites were synthesized due to the hydrogen bonding and hydrophobic interactions. The insulin entrapped in the nanocomposites was in an amorphous state confirmed by X-ray diffraction. The cell culture demonstrated that both the nanocomposites showed no detectable cytotoxicity with relative cell viability all above 85%. The pharmacological bioavailability after oral administration of insulin-SCG-PAC at a dose of 100 IU/kg was found to be 6.98 ± 1.20% in diabetic rats without any sharp fluctuations in 8 h.

Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles

Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA) as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs) to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone) (PCL) was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion–diffusion–evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA. From these results, it can be concluded that incorporation of EA into PCL as NPs enhances its oral bioavailability and activity.

In vivo fate of lipid-silybin conjugate nanoparticles: Implications on enhanced oral bioavailability

Lipid-drug conjugates (LDCs) of a poorly soluble and poorly permeable drug silybin (SB) and lipids with different chain lengths (6C, 12C, 18C) are synthesized and formulated into solid lipid nanoparticles (SLNs). The in vivo fate of LDCs as well as SLNs is investigated by tracking either SB or LDCs or SLNs. LDCs are prone to be hydrolyzed by lipases either in simulated gastrointestinal media or in Caco-2 cell lines in a lipid chain length-dependent mode. The oral bioavailability of SB is enhanced by 5-7-fold in comparison with a fast-release formulation. No integral LDCs are detected in plasma confirms the readily degradable nature of LDCs. The absorption of LDCs by enteric epithelia and subsequent transportation into circulation might play a leading role in absorption enhancement, whereas the contribution of then M-cell pathway is not as remarkable. A shorter lipid chain favors earlier lipolysis and faster absorption along the intestine-to-circulation path.

Lipid-core nanocapsules increase the oral efficacy of quercetin in cutaneous leishmaniasis

New oral treatments are needed for all forms of leishmaniasis. Here, the improved oral efficacy of quercetin (Qc) and its penta-acetylated derivative (PQc) was evaluated in cutaneous leishmaniasis after encapsulation in lipid-core nanocapsules (LNCs) of poly(ε-caprolactone). Leishmania amazonensis-infected BALB/c mice were given 51 daily oral doses of free drugs (16 mg kg-1) or LNC-loaded drugs (0·4 mg kg-1). While treatment with free Qc reduced the lesion sizes and parasite loads by 38 and 71%, respectively, LNC-Qc produced 64 and 91% reduction, respectively. The antileishmanial efficacy of PQc was similar but not as potently improved by encapsulation as Qc. None of the treatments increased aspartate aminotransferase, alanine aminotransferase or creatinine serum levels. These findings indicate that when encapsulated in LNC, Qc and, to a lesser extent, PQc can safely produce an enhanced antileishmanial effect even at a 40-fold lower dose, with implications for the development of a new oral drug for cutaneous leishmaniasis.

Eudragit S100-Coated Chitosan Nanoparticles Co-loading Tat for Enhanced Oral Colon Absorption of Insulin

In order to improve oral absorption of insulin, especially the absorption at the colon, Eudragit S100® (ES)-coated chitosan nanoparticles loading insulin and a trans-activating transcriptional peptide (Tat) were employed as the vehicle. In vitro releases of insulin and Tat from ES-coated chitosan nanoparticles had a pH-dependant characteristic. A small amount of the contents was released from the coated nanoparticles at pH 1.2 simulated gastric fluid, while a fairly fast and complete release was observed in pH 7.4 medium. Caco-2 cell was used as the model of cellular transport and uptake studies. The results showed that the cellular transport and uptake of insulin for ES-coated chitosan nanoparticles co-loading insulin and Tat (ES-Tat-cNPs) were about 3-fold and 4-fold higher than those for the nanoparticles loading only insulin (ES-cNPs), respectively. The evaluations in vivo of ES-Tat-cNPs were conducted on diabetic rats and normal minipigs, respectively. The experimental results on rats revealed that the pharmacodynamical bioavailability of ES-Tat-cNPs had 2.16-fold increase compared with ES-cNPs. After oral administration of nanoparticle suspensions to the minipigs, insulin bioavailability of ES-Tat-cNPs was 1.73-fold higher than that of ES-cNPs, and the main absorption site of insulin was probably located in the colon for the two nanoparticles. In summary, this report provided an exploratory means for the improvement of oral absorption of insulin.

Mechanisms of transport of polymeric and lipidic nanoparticles across the intestinal barrier

Unraveling the mechanisms of nanoparticle transport across the intestinal barrier is essential for designing more efficient nanoparticles for oral administration. The physicochemical parameters of the nanoparticles (e.g., size, surface charge, chemical composition) dictate nanoparticle fate across the intestinal barrier. This review aims to address the most important findings regarding polymeric and lipidic nanoparticle transport across the intestinal barrier, including the evaluation of critical physicochemical parameters of nanoparticles that affect nanocarrier interactions with the intestinal barrier.

How to design the surface of peptide-loaded nanoparticles for efficient oral bioavailability?

The oral administration of proteins is a current challenge to be faced in the field of therapeutics. There is currently much interest in nanocarriers since they can enhance oral bioavailability. For lack of a clear definition, the key characteristics of nanoparticles have been highlighted. Specific surface area is one of these characteristics and represents a huge source of energy that can be used to control the biological fate of the carrier. The review discusses nanocarrier stability, mucus interaction and absorption through the intestinal epithelium. The protein corona, which has raised interest over the last decade, is also discussed. The universal ideal surface is a myth and over-coated carriers are not a solution either. Besides, common excipients can be useful on several targets. The suitable design should rather take into account the composition, structure and behavior of unmodified nanomaterials.

Transition from passive to active targeting of oral insulin nanomedicines: enhancement in bioavailability and glycemic control in diabetes

Oral insulin nanomedicines are effective tools for therapy and management of both Type I and Type II diabetes. This review summarizes the various nanocarriers developed so far in the literature for oral delivery of insulin. It includes lipid-based (i.e., solid lipid nanoparticles and liposomes) and polymeric-based insulin nanomedicines (i.e., chitosan nanoparticles, alginate nanoparticles, dextran nanoparticles and nanoparticles of synthetic polymers) for sustained, controlled and targeted oral delivery of insulin. Mainly, goblet cell-targeting, vitamin B12 receptor-targeting, folate receptor-targeting and transferrin receptor-targeting aspects were focused. Currently, passive and active targeting approaches of oral insulin nanomedicines have improved the oral absorption of insulin and its bioavailability (up to 14%) that produced effective glycaemic control in in vivo models. These results indicate a promising future of oral insulin nanomedicines for the treatment of diabetes.

Dual chitosan/albumin-coated alginate/dextran sulfate nanoparticles for enhanced oral delivery of insulin

The potential of nanoparticles (NPs) to overcome the barriers for oral delivery of protein drugs have led to the development of platforms capable of improving their bioavailability. However, despite the progresses in drug delivery technologies, the success of oral delivery of insulin remains elusive and the disclosure of insulin mechanisms of absorption remains to be clarified. To overcome multiple barriers faced by oral insulin and to enhance the insulin permeability across the intestinal epithelium, here insulin-loaded alginate/dextran sulfate (ADS)-NPs were formulated and dual-coated with chitosan (CS) and albumin (ALB). The nanosystem was characterized by its pH-sensitivity and mucoadhesivity, which enabled to prevent 70% of in vitro insulin release in simulated gastric conditions and allowed a sustained insulin release following the passage to simulated intestinal conditions. The pH and time-dependent morphology of the NPs was correlated to the release and permeation profile of insulin. Dual CS/ALB coating of the ADS-NPs demonstrated augmented intestinal interactions with the intestinal cells in comparison to the uncoated-NPs, resulting in a higher permeability of insulin across Caco-2/HT29-MTX/Raji B cell monolayers. The permeability of the insulin-loaded ALB-NPs was reduced after the temperature was decreased and after co-incubation with chlorpromazine, suggesting an active insulin transport by clathrin-mediated endocytosis. Moreover, the permeability inhibition with the pre-treatment with sodium chlorate suggested that the interaction between glycocalix and the NPs was critical for insulin permeation. Overall, the developed nanosystem has clinical potential for the oral delivery of insulin and therapy of type 1 diabetes mellitus.