The role of chitosan on oral delivery of peptide-loaded nanoparticle formulation

Advances in inhaler therapy for asthma and chronic obstructive pulmonary disease: a comprehensive review of Fostair™ and Trimbow™

The management of asthma and chronic obstructive pulmonary disease (COPD) poses considerable challenges due to the intricate nature of these respiratory conditions. Fostair™ and Trimbow™, two pressurized metered dose inhalers, have emerged as noteworthy therapeutic options for treating both asthma and COPD. Fostair combines an inhaled corticosteroid, specifically beclometasone dipropionate, with a long-acting beta2-agonist, formoterol fumarate dihydrate, offering a dual-action approach to mitigate airway inflammation and bronchoconstriction. Conversely, Trimbow integrates a tri-particulate formulation consisting of beclometasone dipropionate, formoterol fumarate dihydrate, and glycopyrronium bromide, providing a comprehensive strategy to target the pathophysiology of COPD and asthma. Recent clinical trials have underscored Trimbow's superior efficacy compared with Fostair, particularly in terms of reducing exacerbation rates and enhancing lung function. However, despite their therapeutic promise, both inhalers encounter challenges, including limited generalizability of study findings and a disparity between in vitro and human trial results. This literature review offers an in-depth analysis of Fostair and Trimbow, delving into their mechanisms of action, clinical applications, and outcomes in human studies for asthma and COPD. Additionally, the review discusses the role of combination therapy in managing respiratory diseases and underscores the necessity for further research to address existing knowledge gaps and optimize therapeutic outcomes.

Insulin Delivery to the Brain via the Nasal Route: Unraveling the Potential for Alzheimer's Disease Therapy

This comprehensive review delves into the potential of intranasal insulin delivery for managing Alzheimer's Disease (AD) while exploring the connection between AD and diabetes mellitus (DM). Both conditions share features of insulin signalling dysregulation and oxidative stress that accelerate inflammatory response. Given the physiological barriers to brain drug delivery, including the blood-brain barrier, intranasal administration emerges as a non-invasive alternative. Notably, intranasal insulin has shown neuroprotective effects, impacting Aβ clearance, tau phosphorylation, and synaptic plasticity. In preclinical studies and clinical trials, intranasally administered insulin achieved rapid and extensive distribution throughout the brain, with optimal formulations exhibiting minimal systemic circulation. The detailed mechanism of insulin transport through the nose-to-brain pathway is elucidated in the review, emphasizing the role of olfactory and trigeminal nerves. Despite promising prospects, challenges in delivering protein drugs from the nasal cavity to the brain remain, including enzymes, tight junctions, mucociliary clearance, and precise drug deposition, which hinder its translation to clinical settings. The review encompasses a discussion of the strategies to enhance the intranasal delivery of therapeutic proteins, such as tight junction modulators, cell-penetrating peptides, and nano-drug carrier systems. Moreover, successful translation of nose-to-brain drug delivery necessitates a holistic understanding of drug transport mechanisms, brain anatomy, and nasal formulation optimization. To date, no intranasal insulin formulation has received regulatory approval for AD treatment. Future research should address challenges related to drug absorption, nasal deposition, and the long-term effects of intranasal insulin. In this context, the evaluation of administration devices for nose-to-brain drug delivery becomes crucial in ensuring precise drug deposition patterns and enhancing bioavailability.

An overview of in vitro and in vivo techniques for characterization of intranasal protein and peptide formulations for brain targeting

The surge in neurological disorders necessitates innovative strategies for delivering active pharmaceutical ingredients to the brain. The non-invasive intranasal route has emerged as a promising approach to optimize drug delivery to the central nervous system by circumventing the blood-brain barrier. While the intranasal approach offers numerous advantages, the lack of a standardized protocol for drug testing poses challenges to both in vitro and in vivo studies, limiting the accurate interpretation of nasal drug delivery and pharmacokinetic data. This review explores the in vitro experimental assays employed by the pharmaceutical industry to test intranasal formulation. The focus lies on understanding the diverse techniques used to characterize the intranasal delivery of drugs targeting the brain. Parameters such as drug release, droplet size measurement, plume geometry, deposition in the nasal cavity, aerodynamic performance and mucoadhesiveness are scrutinized for their role in evaluating the performance of nasal drug products. The review further discusses the methodology for in vivo characterization in detail, which is essential in evaluating and refining drug efficacy through the nose-to-brain pathway. Animal models are indispensable for pre-clinical drug testing, offering valuable insights into absorption efficacy and potential variables affecting formulation safety. The insights presented aim to guide future research in intranasal drug delivery for neurological disorders, ensuring more accurate predictions of therapeutic efficacy in clinical contexts.

A novel approach to insulin delivery via oral route: Milk fat globule membrane derived liposomes as a delivery vehicle

The current research endeavor seeks to unlock the potential of orally administered insulin formulations by utilizing liposomes derived from the fat globule membrane (MFGM) of camel milk as carriers for insulin. This pursuit emerges as a result of the recognized limitations of subcutaneous insulin therapy. The liposomes were meticulously created using the thin film hydration method, followed by comprehensive chemical and morphological analyses. Additionally, comprehensive safety assessments were carried out in vitro and in vivo, revealing significant findings. The Fourier-transform infrared (FTIR) spectrum confirmed the presence of insulin within the liposomes, demonstrating changes in their size and charge. The in vitro cytotoxicity analysis, performed on HEK-293 cell lines through the MTT assay, yielded results indicating a cell viability of over 90%. In the in vivo investigation, diabetic rats induced by STZ were utilized to evaluate the effects of the liposomes, revealing substantial reductions in blood glucose levels, bilirubin, alkaline phosphatase (ALP), albumin, and alanine aminotransferase (ALT) levels. Hepatic histopathological assessments showed signs of recovery across all treatment groups, with no observable microscopic changes in renal tissue. This investigation highlights the significant hypoglycemic effects observed in insulin-loaded liposomes derived from MFGM obtained from camel milk when administered orally.

Effect of C7-3-Peptide-Loaded Chitosan Nanoparticles Against Multi-Drug-Resistant Neisseria gonorrhoeae

Introduction

The emergence of Neisseria gonorrhoeae-resistant strains represents one of the most urgent global threats. In this regard, C7-3 peptide is one of the anti-virulence therapies that has demonstrated promising anti-gonococcal activity. Accordingly, this research aimed to formulate C7-3 peptide and its derivatives in chitosan nanoparticles.

Methods

The peptide loaded chitosan nanoparticles were prepared using ion gelation method, and their physicochemical characteristics were investigated. The anti-gonococcal and antibiofilm activity of prepared NPs was assessed, and their cytotoxicity in human ovarian cells was evaluated.

Results

All prepared NPs were optimized for the smallest particle size of 136.9 to 168.3 nm. The EE% of C7-3, C7-3m1, and C7-3m2 CNPs reached 90.2, 92.5, and 91.8%, respectively. An in vitro release study demonstrated a continuous sustained-release pattern of C7-3 peptide from NPs. The SDS-PAGE assay confirmed the integrity of C7-3 peptide after the fabrication process. When comparing each peptide alone, the generated NPs demonstrated higher anti-gonococcal and anti-biofilm effectiveness against standard and resistant bacterial strains under anaerobic conditions. The cytotoxicity experiments revealed the cytocompatibility of NPs in HeLa cell lines. Given the advantages of enhanced anti-gonococcal activity of the C7-3 peptide and its derivatives when loaded with CNPs, as well as the antimicrobial properties of chitosan NPs, the reported NPs have great potential in the treatment of gonococcal infection.

A Comprehensive Review on Prospects of Polymeric Nanoparticles for Treatment of Diabetes Mellitus: Receptors-Ligands, In vitro & In vivo Studies

As per International Diabetes Federation Report 2022, worldwide diabetes mellitus (DM) caused 6.7M moralities and ~537M adults suffering from diabetes mellitus. It is a chronic condition due to β-cell destruction or insulin resistance that leads to insulin deficiency. This review discusses Type-1 DM and Type-2 DM pathophysiology in detail, with challenges in management and treatment. The toxicity issues of conventional drugs and insulin injections are complex to manage. Thus, there is a need for technological intervention. In recent years, nanotechnology has found a fruitful advancement of novel drug delivery systems that might potentially increase the efficacy of anti-diabetic drugs. Amongst nano-formulations, polymeric nanoparticles have been studied to enhance the bioavailability and efficacy of anti-diabetic drugs and insulin. In the present review, we summarized polymeric nanoparticles with different polymers utilized to deliver anti-diabetic drugs with in vitro and in vivo studies. Furthermore, this review also includes the role of receptors and ligands in diabetes mellitus and the utilization of receptor-ligand interaction to develop targeted nanoparticles. Additionally, we discussed the utility of nanoparticles for the delivery of phytoconstituents which aids in protecting the oxidative stress generated during diabetes mellitus. Atlast, this article also comprises of numerous patents that have been filed or granted for the delivery of antidiabetic and anticancer molecules for the treatment of diabetes mellitus and pancreatic cancer.

Beyond the polysaccharide and glycoconjugate vaccines for Streptococcus pneumoniae: Does protein/peptide nanovaccines hold promises?

Streptococcus pneumoniae having almost 98 serotypes and being common cause of acute otitis media, pneumonia, bacteremia, meningitis etc., which results in high mortality and morbidity globally. Although vaccines like PCV-13 and PPV-23 are available, some problems like serotype replacement and poor immunogenicity in children, old age and immunocompromised people has been observed. To overcome these drawbacks protein/peptide-based vaccine can be a good strategy as these provides wide serotype coverage. However, immunogenicity of protein subunit vaccines is lower, that issue can be solved by using adjuvants. Recently nanoparticles as an adjuvant for vaccine delivery being used, which has provided not only good immunogenicity but also improved delivery and efficiency of protein-based vaccines. In this review we have discussed the latest advancement of nanoparticles-based protein/peptide vaccine delivery for Streptococcus pneumoniae.

Peptide-Based Agents for Cancer Treatment: Current Applications and Future Directions

Peptide-based strategies have received an enormous amount of attention because of their specificity and applicability. Their specificity and tumor-targeting ability are applied to diagnosis and treatment for cancer patients. In this review, we will summarize recent advancements and future perspectives on peptide-based strategies for cancer treatment. The literature search was conducted to identify relevant articles for peptide-based strategies for cancer treatment. It was performed using PubMed for articles in English until June 2023. Information on clinical trials was also obtained from ClinicalTrial.gov. Given that peptide-based strategies have several advantages such as targeted delivery to the diseased area, personalized designs, relatively small sizes, and simple production process, bioactive peptides having anti-cancer activities (anti-cancer peptides or ACPs) have been tested in pre-clinical settings and clinical trials. The capability of peptides for tumor targeting is essentially useful for peptide-drug conjugates (PDCs), diagnosis, and image-guided surgery. Immunomodulation with peptide vaccines has been extensively tested in clinical trials. Despite such advantages, FDA-approved peptide agents for solid cancer are still limited. This review will provide a detailed overview of current approaches, design strategies, routes of administration, and new technological advancements. We will highlight the success and limitations of peptide-based therapies for cancer treatment.

Challenges and opportunities in delivering oral peptides and proteins

INTRODUCTION

Rapid advances in bioengineering enable the use of complex proteins as therapeutic agents to treat diseases. Compared with conventional small molecule drugs, proteins have multiple advantages, including high bioactivity and specificity with low toxicity. Developing oral dosage forms with active proteins is a route to improve patient compliance and significantly reduce production costs. However, the gastrointestinal environment remains a challenge to this delivery path due to enzymatic degradation, low permeability, and weak absorption, leading to reduced delivery efficiency and poor clinical outcomes.

AREAS COVERED

This review describes the barriers to oral delivery of peptides and complex proteins, current oral delivery strategies utilized and the opportunities and challenges ahead to try and circumvent these barriers. Oral protein drugs on the market and clinical trials provide insights and approaches for advancing delivery strategies.

EXPERT OPINION

Although most current studies on oral protein delivery rely on in vitro and in vivo animal data, the safety and limitations of the approach in humans remain uncertain. The shortage of clinical data limits the development of new or alternative strategies. Therefore, designing appropriate oral delivery strategies remains a significant challenge and requires new ideas, innovative design strategies and novel model systems.

Chitosan Nanoparticles as Oral Drug Carriers

The use of nanoparticles as drug delivery systems has increased in importance in the last decades. Despite the disadvantages of difficulty swallowing, gastric irritation, low solubility, and poor bioavailability, oral administration stands out as the most widely used route for therapeutic treatments, though it may not always be the most effective route. The effect of the first hepatic pass is one of the primary challenges that drugs must overcome to carry out their therapeutic effect. For these reasons, controlled-release systems based on nanoparticles synthesized from biodegradable natural polymers have been reported to be very efficient in enhancing oral delivery in multiple studies. Chitosan has been shown to have an extensive variability of properties and roles in the pharmaceutical and health fields; of its most important properties are the ability to encapsulate and transport drugs within the body and enhance the drug interaction with the target cells, which improves the efficacy of the encapsulated drugs. The physicochemical properties of chitosan give it the ability to form nanoparticles through multiple mechanisms, which will be addressed in this article. The present review article focuses on highlighting the applications of chitosan nanoparticles for oral drug delivery.

A Nanomedicine Structure-Activity Framework for Research, Development, and Regulation of Future Cancer Therapies

Despite their clinical success in drug delivery applications, the potential of theranostic nanomedicines is hampered by mechanistic uncertainty and a lack of science-informed regulatory guidance. Both the therapeutic efficacy and the toxicity of nanoformulations are tightly controlled by the complex interplay of the nanoparticle's physicochemical properties and the individual patient/tumor biology; however, it can be difficult to correlate such information with observed outcomes. Additionally, as nanomedicine research attempts to gradually move away from large-scale animal testing, the need for computer-assisted solutions for evaluation will increase. Such models will depend on a clear understanding of structure-activity relationships. This review provides a comprehensive overview of the field of cancer nanomedicine and provides a knowledge framework and foundational interaction maps that can facilitate future research, assessments, and regulation. By forming three complementary maps profiling nanobio interactions and pathways at different levels of biological complexity, a clear picture of a nanoparticle's journey through the body and the therapeutic and adverse consequences of each potential interaction are presented.

Chitosan Nanoparticles in Atherosclerosis-Development to Preclinical Testing

Chitosan is a natural biopolymer that is present in an abundant supply in sources such as crustacean shells, mushrooms, and insect exoskeletons. It can be used to make a variety of types of drug formulations and is generally safe to use in vivo; plus, it has inherent cholesterol-reducing properties. While an abundance of papers has tested this biopolymer in nanoparticles in cancer and diabetes research, there is a lag of usage, and hence the paucity of information, in the area of cardiovascular research, specifically in atherosclerosis, the topic of this review. This review highlights some of the deficiencies in this niche area of research, examines the range of chitosan nanoparticles that have been researched to date, and proposes several ways forward to advance this field. Nanoparticles used for both diagnostic and therapeutic purposes are reviewed, with a discussion on how these nanoparticles could be better researched in future and what lays ahead as the field potentially moves towards clinical trials in future.

Drug release study of the chitosan-based nanoparticles

Recently, multifunctional drug delivery systems (DDSs) have been designed to provide a comprehensive approach with multiple functionalities, including diagnostic imaging, targeted drug delivery, and controlled drug release. Chitosan-based drug nanoparticles (CSNPs) systems are employed as diagnostic imaging and delivering the drug to particular targeted sites in a regulated manner. Drug release is an important factor in ensuring high reproducibility, stability, quality control of CSNPs, and scientific-based for developing CSNPs. Several factors influence drug release from CSNPs, including composition, composition ratio, ingredient interactions, and preparation methods. Early, CSNPs were used for improving drug solubility, stability, pharmacokinetics, and pharmacotherapeutics properties. Chitosan has been developed toward a multifunctional drug delivery system by exploring positively charged properties and modifiable functional groups. Various modifications to the polymer backbone, charge, or functional groups will undoubtedly affect the drug release from CSNPs. The drug release from CSNPs has a significant influence on its therapeutic actions. Our review's objective was to summarize and discuss the relationship between the modification in CSNPs as multifunctional delivery systems and drug release properties and kinetics of the drug release model. Kinetic models help describe the release rate, leading to increased efficiency, accuracy, the safety of the dose, optimizing the drug delivery device's design, evaluating the drug release rate, and improvement of patient compatibility. In conclusion, almost all CSNPs showed bi-phasic release, initial burst release drug in a particular time followed controlled manner release in achieving the expected release, stimuli external can be applied. CSNPs are a promising technique for multifunctional drug delivery systems.

Ibuprofen-Loaded Chitosan-Lipid Nanoconjugate Hydrogel with Gum Arabic: Green Synthesis, Characterisation, In Vitro Kinetics Mechanistic Release Study and PGE2 Production Test

Ibuprofen is a well-known non-steroidal anti-inflammatory (NSAID) medicine that is often used to treat inflammation in general. When given orally, it produces gastrointestinal issues which lead to lower patient compliance. Ibuprofen transdermal administration improves both patient compliance and the efficacy of the drug. Nanoconjugation hydrogels were proposed as a controlled transdermal delivery tool for ibuprofen. Six formulations were prepared using different compositions including chitosan, lipids, gum arabic, and polyvinyl alcohol, through ionic interaction, maturation, and freeze–thaw methods. The formulations were characterised by size, drug conjugation efficiency, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Further analysis of optimised hydrogels was performed, including X-ray diffraction (XRD), rheology, gel fraction and swelling ability, in vitro drug release, and in vitro macrophage prostaglandin E2 (PGE₂) production testing. The effects of ibuprofen’s electrostatic interaction with a lipid or polymer on the physicochemical and dissolution characterisation of ibuprofen hydrogels were evaluated. The results showed that the S3 (with lipid conjugation) hydrogel provided higher conjugation efficiency and prolonged drug release compared with the S6 hydrogel.

Novel Peptide Therapeutic Approaches for Cancer Treatment

Peptides are increasingly being developed for use as therapeutics to treat many ailments, including cancer. Therapeutic peptides have the advantages of target specificity and low toxicity. The anticancer effects of a peptide can be the direct result of the peptide binding its intended target, or the peptide may be conjugated to a chemotherapy drug or radionuclide and used to target the agent to cancer cells. Peptides can be targeted to proteins on the cell surface, where the peptide–protein interaction can initiate internalization of the complex, or the peptide can be designed to directly cross the cell membrane. Peptides can induce cell death by numerous mechanisms including membrane disruption and subsequent necrosis, apoptosis, tumor angiogenesis inhibition, immune regulation, disruption of cell signaling pathways, cell cycle regulation, DNA repair pathways, or cell death pathways. Although using peptides as therapeutics has many advantages, peptides have the disadvantage of being easily degraded by proteases once administered and, depending on the mode of administration, often have difficulty being adsorbed into the blood stream. In this review, we discuss strategies recently developed to overcome these obstacles of peptide delivery and bioavailability. In addition, we present many examples of peptides developed to fight cancer.

Characterization, Bioactivity and Application of Chitosan-Based Nanoparticles in a Food Emulsion Model

In this study, chitosan nanoparticles (CNPs) were prepared by the ionic gelation technique with tripolyphosphate (TPP), and the effect of CNP composition and physicochemical characteristics were evaluated. After the synthesis optimization, CNPs were used as carriers for a fish protein hydrolysate (FPH) with bioactive properties (CNPH). The physicochemical characteristics, antioxidant capacity and antimicrobial, antihypertensive and emulsifier properties of unloaded and loaded CNPs in a food system model were studied. CNPH showed a uniform particle distribution, size ~200 nm, high stability (zeta potential around 30 mV), radical scavenging activity and increased antimicrobial activity against Staphylococcus aureus, Shigella sonnei and Aeromonas hydrophila. Additionally, CNPH showed an angiotensin I-converting enzyme (ACE)-inhibitory activity of 63.6% and, when added to a food emulsion model, this system containing CNPs, with or without FHP, exhibited improved food emulsion stability. Thus, CNPs were able to carry the FPH while maintaining their bioactive properties and can be an alternative to the delivery of bioactive peptides with potential as an emulsion stabilizer for food applications.

Thymoquinone-entrapped chitosan-modified nanoparticles: formulation optimization to preclinical bioavailability assessments

The major limitation with the oral administration of most of the phytochemicals is their low aqueous solubility and bioavailability. Thymoquinone (THQ) is one of the most widely used phytochemicals used to treat a variety of diseases. However, strong lipophilic characteristics limit its clinical application. Therefore, this study was aimed to design novel chitosan (C) modified polycaprolactone (PL) nanoparticles (NPs) for improved oral bioavailability of THQ. THQ-CPLNPs was optimized 33-Box-Behnken design. After that, the optimized THQ-CPLNPs was characterized by different parameters. THQ-CPLNPs showed the size, PDI, and ZP of 182.32 ± 6.46 nm, 0.179 ± 0.012, and +21.36 ± 1.22 mV, respectively. The entrapment and loading capacity were found to be 79.86 ± 4.36%, and 13.45 ± 1.38%, respectively. THQ-CPLNPs exhibited burst release in initial 2 h followed by prolonged release up to 24 h in simulated intestinal fluids. THQ-CPLNPs showed excellent mucoadhesion properties which were further confirmed with the intestinal permeation study as well as confocal microscopy. The study revealed higher permeation of THQ-CPLNPs compared to neat THQ suspension (THQ-S). Moreover, in vivo gastric irritation study revealed good compatibility of THQ-CPLNPs with the gastric mucosa. Furthermore, pharmacokinetic results depicted ∼3.53-fold improved oral bioavailability of THQ from THQ-CPLNPs than THQ-S. Therefore, from the findings, it was concluded that the prepared polymeric NPs could be an effective delivery system for improved oral bioavailability of THQ.

The Present and Future Role of Microfluidics for Protein and Peptide-Based Therapeutics and Diagnostics

The implementation of peptide-based molecules within the medical field has vast potential, owing to their unique nature and predictable physicochemical profiles. However, peptide therapeutic usage is hindered by delivery-related challenges, meaning that their formulations must be altered to overcome these limitations. This process could be propelled by applying microfluidics (MFs) due to its highly controllable and adaptable attributes; however, therapeutic research within this field is extremely limited. Peptides possess multifunctional roles within therapeutic formulations, ranging from enhancing target specificity to acting as the active component of the medicine. Diagnostically, MFs are well explored in the field of peptides, as MFs provide an unsullied platform to provide fast yet accurate examinations. The capacity to add attributes, such as integrated sensors and microwells, to the MF chip, only enhances the attractiveness of MFs as a diagnostic platform. The structural individuality of peptides makes them prime candidates for diagnostic purposes, for example, antigen detection and isolation. Therefore, this review provides a useful insight into the current applications of MFs for peptide-based therapy and diagnostics and highlights potential gaps in the field that are yet to be explored or optimized.

β-Cyclodextrin-containing chitosan-oligonucleotide nanoparticles improve insulin bioactivity, gut cellular permeation and glucose consumption

OBJECTIVES

The main objective of the present study was to develop a nanoparticulate drug delivery system that can protect insulin against harsh conditions in the gastrointestinal (GI) tract. The effects of the following employed techniques, including lyophilisation, cross-linking and nanoencapsulation, on the physicochemical properties of the formulation were investigated.

METHODS

We herein developed a nanocarrier via ionotropic gelation by using positively charged chitosan and negatively charged Dz13Scr. The lyophilised nanoparticles with optimal concentrations of tripolyphosphate (cross-linking agent) and β-cyclodextrin (stabilising agent) were characterised by using physical and cellular assays.

KEY FINDINGS

The addition of cryoprotectants (1% sucrose) in lyophilisation improved the stability of nanoparticles, enhanced the encapsulation efficiency, and ameliorated the pre-mature release of insulin at acidic pH. The developed lyophilised nanoparticles did not display any cytotoxic effects in C2C12 and HT-29 cells. Glucose consumption assays showed that the bioactivity of entrapped insulin was maintained post-incubation in the enzymatic medium.

CONCLUSIONS

Freeze-drying with appropriate cryoprotectant could conserve the physiochemical properties of the nanoparticles. The bioactivity of the entrapped insulin was maintained. The prepared nanoparticles could facilitate the permeation of insulin across the GI cell line.

Fabrication techniques for the preparation of orally administered insulin nanoparticles

The development of orally administered protein drugs is challenging due to their intrinsic unfavourable features, including large molecular size and poor chemical stability, both of which limit gastrointestinal (GI) absorption efficiency. Nanoparticles can overcome the GI barriers effectively and improve the oral bioavailability of proteins in the GI tract. They possess large surface area to volume ratio, and can facilitate the GI absorption of nanoparticles via the paracellular and transcellular routes. Nanoparticles can be prepared by various fabrication techniques that can encapsulate the fragile therapeutic proteins via hydrophobic bonding and electrostatic interaction. A desirable technique should involve minimal harsh conditions and encapsulate therapeutic proteins with preserved functionalities. The current review examines the characteristics of each preparation technique, and illustrates the examples of insulin-loaded nanoparticles that have been developed in each fabrication method. The following techniques, which include nanoprecipitation, hydrophobic conjugation, flash nanocomplexation, double emulsion, ionotropic gelation, and layer-by-layer adsorption, have been used to formulate ligand-modified nanoparticles for targeted delivery of insulin. Other techniques, including reduction, complex coacervation (polyelectrolyte complexation), hydrophobic ion pairing and emulsion solvent diffusion method, and sol-gel technology, were also discussed in the latter part of the review due to their extensive use in fabrication of insulin nanoparticles. This review also discusses the strategies that have been utilised during the formulation process to improve the stability and bioactivity of therapeutic proteins.

Chitosan/casein based microparticles with a bilayer shell-core structure for oral delivery of nattokinase

Nattokinase is a thrombolytic enzyme obtained from Japanese traditional food natto for prevention and cure of thrombosis-related cardiovascular diseases. However, the effectiveness of nattokinase through oral intake is limited, due to the loss of thrombolytic activity in the acidic gastric juice. In this study, we develop a functional oral delivery system of nattokinase, in which chitosan microparticles were used as the carrier core to load nattokinase via genipin crosslinking and then covered by a casein-based protective shell via transglutaminase (TG) crosslinking. The results of in vitro and in vivo assays, in the aspects of bioactivity, release dynamics, and therapeutic effects, indicated that the bilayer shell-core structure could protect loaded nattokinase from destruction in the gastric juice and achieve its controlled-release in the intestine. This work demonstrates the availability of bilayer shell-core structure design in oral delivery of nattokinase and shows its high potential for application as an anti-thrombosis functional food additive.

PEGylated Lipid Polymeric Nanoparticle-Encapsulated Acyclovir for In Vitro Controlled Release and Ex Vivo Gut Sac Permeation

Currently, pharmaceutical research is directed wide range for developing new drugs for oral administration to target disease. Acyclovir formulation is having common issues of short half-life and poor permeability, causing messy treatment which results in patient incompliance. The present study formulates a lipid polymeric hybrid nanoparticles for antiviral acyclovir (ACV) agent with Phospholipon® 90G (lecithin), chitosan, and polyethylene glycol (PEG) to improve controlled release of the drugs. The study focused on the encapsulation of the ACV in lipid polymeric particle and their sustained delivery. The formulation developed for the self-assembly of chitosan and lecithin to form a shell encapsulating acyclovir, followed by PEGylation. Optimisation was performed via Box-Behnken Design (BBD), forming nanoparticles with size of 187.7 ± 3.75 nm, 83.81 ± 1.93% drug-entrapped efficiency (EE), and + 37.7 ± 1.16 mV zeta potential. Scanning electron microscopy and transmission electron microscopy images displayed spherical nanoparticles formation. Encapsulation of ACV and complexity with other physical parameters are confirmed through analysis using Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. Nanoparticle produced was capable of achieving 24-h sustained release in vitro on gastric and intestinal environments. Ex vivo study proved the improvement of acyclovir's apparent permeability from 2 × 10-6 to 6.46 × 10-6 cm s-1. Acyclovir new formulation was achieved to be stable up to 60 days for controlled release of the drugs. Graphical abstract.

C2C12 cell model: its role in understanding of insulin resistance at the molecular level and pharmaceutical development at the preclinical stage

OBJECTIVES

The myoblast cell line, C2C12, has been utilised extensively in vitro as an examination model in understanding metabolic disease progression. Although it is indispensable in both preclinical and pharmaceutical research, a comprehensive review of its use in the investigation of insulin resistance progression and pharmaceutical development is not available.

KEY FINDINGS

C2C12 is a well-documented model, which can facilitate our understanding in glucose metabolism, insulin signalling mechanism, insulin resistance, oxidative stress, reactive oxygen species and glucose transporters at cellular and molecular levels. With the aid of the C2C12 model, recent studies revealed that insulin resistance has close relationship with various metabolic diseases in terms of disease progression, pathogenesis and therapeutic management. A holistic, safe and effective disease management is highly of interest. Therefore, significant efforts have been paid to explore novel drug compounds and natural herbs that can elicit therapeutic effects in the targeted sites at both cellular (e.g. mitochondria, glucose transporter) and molecular level (e.g. genes, signalling pathway).

SUMMARY

The use of C2C12 myoblast cell line is meaningful in pharmaceutical and biomedical research due to their expression of GLUT-4 and other features that are representative to human skeletal muscle cells. With the use of the C2C12 cell model, the impact of drug delivery systems (nanoparticles and quantum dots) on skeletal muscle, as well as the relationship between exercise, pancreatic β-cells and endothelial cells, was discovered.

Development of orally administered insulin-loaded polymeric-oligonucleotide nanoparticles: statistical optimization and physicochemical characterization

INTRODUCTION

Therapeutic peptides are administered via parenteral route due to poor absorption in the gastrointestinal (GI) tract, instability in gastric acid, and GI enzymes. Polymeric drug delivery systems have achieved significant interest in pharmaceutical research due to its feasibility in protecting proteins, tissue targeting, and controlled drug release pattern.

MATERIALS AND METHODS

In this study, the size, polydispersity index, and zeta potential of insulin-loaded nanoparticles were characterized by dynamic light scattering and laser Doppler micro-electrophoresis. The main and interaction effects of chitosan concentration and Dz13Scr concentration on the physicochemical properties of the prepared insulin-loaded nanoparticles (size, polydispersity index, and zeta potential) were evaluated statistically using analysis of variance. A robust procedure of reversed-phase high-performance liquid chromatography was developed to quantify insulin release in simulated GI buffer. Results and discussion: We reported on the effect of two independent parameters, including polymer concentration and oligonucleotide concentration, on the physical characteristics of particles. Chitosan concentration was significant in predicting the size of insulin-loaded CS-Dz13Scr particles. In terms of zeta potential, both chitosan concentration and squared term of chitosan were significant factors that affect the surface charge of particles, which was attributed to the availability of positively-charged amino groups during interaction with negatively-charged Dz13Scr. The excipients used in this study could fabricate nanoparticles with negligible toxicity in GI cells and skeletal muscle cells. The developed formulation could conserve the physicochemical properties after being stored for 1 month at 4 °C.

CONCLUSION

The obtained results revealed satisfactory results for insulin-loaded CS-Dz13Scr nanoparticles (159.3 nm, pdi 0.331, -1.08 mV). No such similar study has been reported to date to identify the main and interactive significance of the above parameters for the characterization of insulin-loaded polymeric-oligonucleotide nanoparticles. This research is of importance for the understanding and development of protein-loaded nanoparticles for oral delivery.

Lyophilisation Improves Bioactivity and Stability of Insulin-Loaded Polymeric-Oligonucleotide Nanoparticles for Diabetes Treatment

The oral bioavailability of therapeutic proteins is limited by the gastrointestinal barriers. Encapsulation of labile proteins into nanoparticles is a promising strategy. In order to improve the stability of nanoparticles, lyophilisation has been used to remove water molecules from the suspension. Although various cryoprotections were employed in the preparation of lyophilised nanoparticles, the selection of cryoprotectant type and concentration in majority of the developed formulation was not justified. In this study, nanoparticles were fabricated by cationic chitosan and anionic Dz13Scr using complex coacervation. The effect of cryoprotectant types (mannitol, sorbitol, sucrose and trehalose) and their concentrations (1, 3, 5, 7, 10% w/v) on physiochemical properties of nanoparticles were measured. Cellular assays were performed to investigate the impact of selected cryoprotectant on cytotoxicity, glucose consumption, oral absorption mechanism and gastrointestinal permeability. The obtained results revealed that mannitol (7% w/v) could produce nanoparticles with small size (313.2 nm), slight positive charge and uniform size distribution. The addition of cryoprotectant could preserve the bioactivity of entrapped insulin and improve the stability of nanoparticles against mechanical stress during lyophilisation. The gastrointestinal absorption of nanoparticles is associated with both endocytic and paracellular pathways. With the use of 7% mannitol, lyophilised nanoparticles induced a significant glucose uptake in C2C12 cells. This work illustrated the importance of appropriate cryoprotectant in conservation of particle physiochemical properties, structural integrity and bioactivity. An incompatible cryoprotectant and inappropriate concentration could lead to cake collapse and formation of heterogeneous particle size populations.

Cyclodextrin Based Nanoparticles for Drug Delivery and Theranostics

Colloidal nanoparticulate technology has been described in the literature as a versatile drug delivery system. But it possesses some inherent lacunae in their formulation. Cyclodextrins (CDs) have been extensively reported for the solubility enhancement of poorly water-soluble drugs. The CDs can cause intervention in aspects related to nanoparticles (NPs) that include improving drug loading in nano-system, improving stability, site-specific/targeted drug delivery, improving solubility profile and absorption of the drug in nanosystem with consequent improvement in bioavailability, with the possibility of controlled release, safety and efficacy. They find application in for simultaneous diagnosis and therapeutics for better treatment procedures. The current communication is focused on the application of CDs to overcome troubles in nanoparticulate formulation and enhancement of their performance. It also envisages the theranostic aspects of CDs.

Bio-nanotechnological advancement of orally administered insulin nanoparticles: Comprehensive review of experimental design for physicochemical characterization

Therapeutic proteins are labile macromolecules that are prone to degradation during production, freeze-drying and storage. Recent studies showed that nanoparticles can enhance the stability and oral bioavailability of encapsulated proteins. Several conventional approaches (enzyme inhibitors, mucoadhesive polymers) and novel strategies (surface modification, ligand conjugation, flash nano-complexation, stimuli-responsive drug delivery systems) have been employed to improve the physiochemical properties of nanoparticles such as size, zeta potential, morphology, polydispersity index, drug release kinetics and cell-targeting capacity. However, clinical translation of protein-based nanoparticle is limited due to poor experimental design, protocol non-compliance and instrumentation set-up that do not reflect the physiological conditions, resulting in difficulties in mass production of nanoparticles and waste in research funding. In order to address the above concerns, we conducted a comprehensive review to examine the experimental designs and conditions for physical characterization of protein-based nanoparticles. Reliable and robust characterization is essential to verify the cellular interactions and therapeutic potential of protein-based nanoparticles. Importantly, there are a number of crucial factors, which include sample treatment, analytical method, dispersants, sampling grid, staining, quantification parameters, temperature, drug concentration and research materials, should be taken into careful consideration. Variations in research protocol and unreasonable conditions that are used in optimization of pharmaceutical formulations can have great impact in result interpretation. Last but not least, we reviewed all novel instrumentations and assays that are available to examine mucus diffusion capacity, stability and bioactivity of protein-based nanoparticles. These include circular dichroism, fourier transform infrared spectroscopy, X-ray diffractogram, UV spectroscopy, differential scanning calorimetry, fluorescence spectrum, Förster resonance energy transfer, NMR spectroscopy, Raman spectroscopy, cellular assays and animal models.

Development of pH-responsive organic-inorganic hybrid nanocomposites as an effective oral delivery system of protein drugs

This research aimed to develop a pH-responsive organic-inorganic hybrid nanocomposite as an effective oral delivery system for protein drugs. Three different nanocomposites were prepared by using bovine serum albumin (BSA) as a model protein. A nanocomplex of BSA with 3-aminopropyl functionalized magnesium phyllosilicate (AC-BSA) was obtained via the spontaneous co-assembly and then sequentially coated with glycol-chitosan (GAC-BSA) and the pH sensitive polymer, Eudragit®L100-55 (EGAC-BSA). These organic-inorganic hybrid nanocomposites exhibited high entrapment efficiency (86-99%) and their structural characteristics were confirmed by using energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism analysis, indicating that the secondary structure of BSA was well retained in the nanocomposites. At pH 1.2, AC-BSA achieved rapid drug release of about 80% within 2 h, while GAC-BSA and EGAC-BSA exhibited slow drug release of 30% and 15%, respectively, indicating that the surface-coated nanocomposites were more stable in the gastric condition. Furthermore, the conformational stability of BSA entrapped in EGAC-BSA was well retained in the presence of proteolytic enzymes, suggesting that EGAC-BSA should be effective in protecting the protein against gastrointestinal harsh environment. Compared to free BSA, all of tested nanocomposites demonstrated 2.1-3.8-fold higher cellular uptake in Caco-2 cells. Furthermore, energy-dependent endocytosis and paracellular pathway contributed to the cellular transport of nanoparticles. After oral administration in rats, EGAC-BSA significantly enhanced the intestinal permeation of BSA compared to free BSA. In conclusion, EGAC-BSA appears to be promising as an effective oral delivery system for proteins with enhanced intestinal absorption.

Multifunctional oral delivery systems for enhanced bioavailability of therapeutic peptides/proteins

In last few years, therapeutic peptides/proteins are rapidly growing in drug market considering their higher efficiency and lower toxicity than chemical drugs. However, the administration of therapeutic peptides/proteins is mainly limited in parenteral approach. Oral therapy which was hampered by harsh gastrointestinal environment and poorly penetrating epithelial barriers often results in low bioavailability (less than 1%-2%). Therefore, delivery systems that are rationally designed to overcome these challenges in gastrointestinal tract and ameliorate the oral bioavailability of therapeutic peptides/proteins are seriously promising. In this review, we summarized various multifunctional delivery systems, including lipid-based particles, polysaccharide-based particles, inorganic particles, and synthetic multifunctional particles that achieved effective oral delivery of therapeutic peptides/proteins.

Advance in oral delivery systems for therapeutic protein

Oral delivery is the most common method of drug administration with high safety and good compliance for patients. However, delivering therapeutic proteins to the target site via oral route involves tremendous challenge due to unfavourable conditions like biochemical barrier, mucus barrier and epithelial barriers. According to the functional differences of various protein drug delivery systems, the recent advances in pH responsive polymer-based drug delivery system, mucoadhesive polymer-based drug delivery system, absorption enhancers-based drug delivery system and composite polymer-based delivery system all were briefly summarised in this review, which not only clarified the clinic potential of these novel drug delivery systems, but also described the way for increasing oral bioavailability of therapeutic protein.