Oral delivery of an anti-diabetic peptide drug via conjugation and complexation with low molecular weight chitosan

Exploring pectin-casein micelles as novel carriers for oral drug delivery of artesunate in the treatment of systemic lupus erythematosus

The oral route of administration is considered the optimal choice for treating chronic diseases due to its convenience and non-invasiveness, which can help prevent physical and mental harm to patients undergoing long-term treatment. However, challenges such as safety, gastrointestinal stability, and bioavailability of oral drugs often limit their effectiveness. Natural biomacromolecule micelles, known for their safety, stability, biocompatibility, and diverse functions, have emerged as promising carriers for oral treatment of chronic diseases like systemic lupus erythematosus (SLE) with fat-soluble drugs. This study introduces an innovative approach by developing an oral delivery system using chemically synthesized natural biomacromolecules to load artesunate for treating SLE. By synthesizing amphiphilic polymer micelles from pectin and casein through a carbodiimide reaction, a more stable structure is achieved. The hydrophobic core of these micelles encapsulates artesunate, resulting in the formation of an oral delivery system (PC-AS) with several advantages, including high drug loading and encapsulation efficiency, small particle size, negative potential, strong stability in the gastrointestinal tract, low toxicity and side effects, strong adhesion in the small intestine, and high bioavailability. These advantages facilitate efficient absorption of artesunate in the gastrointestinal tract, leading to improved bioavailability and effective alleviation of SLE-like symptoms in MRL/lpr mice. By utilizing chemically synthesized natural macromolecular micelles for delivering artesunate in the treatment of SLE, this study overcomes the oral barriers associated with the original drug and presents a novel solution for the long-term oral treatment of chronic diseases.

Free-standing carboxymethyl cellulose film incorporating nanoformulated pomegranate extract for meat packaging

This study aimed to explore an innovative approach to enhancing the shelf-life and quality of meat products through the application of an active packaging system. The study involved the development of new free-standing carboxymethyl cellulose (CMC) nanocomposite films incorporated with nanoencapsulated flavonoids derived from pomegranate extract. The loaded flavonoids, known for their antioxidant and antimicrobial properties, were nanoencapsulated via a self-assembly approach in a mixture of chitosan and sodium alginate to improve their stability, solubility, and controlled release characteristics. Chemical structure, size, and morphology of the obtained nanoparticles (Pg-NPs) were studied with FTIR, zeta-sizer, and TEM. The Pg-NPs showed particle size of 232 nm, and zeta-potential of -20.7 mV. Various free-standing nanocomposite films were then developed via incorporation of Pg-NPs into CMC-casted films. FTIR, SEM, thermal and mechanical properties, and surface wettability were intensively studied for the nanocomposite films. Barrier properties against water vapor were investigated at 2022 g·m-2d-1. The nanocomposite films possessed superior properties for inhibiting bacterial growth and extending the shelf-life of beef and poultry meat for 12 days compared with the Pg-NPs-free CMC films. This study presented a promising approach for development of active packaging systems with improved antimicrobial and antioxidant properties, and economic and environmental impacts.

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis: Current Knowledge and Future Perspectives

Atherosclerosis (AS) is characterized by impairment and apoptosis of endothelial cells, continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells, which is documented as the traditional cellular paradigm. However, the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis, transdifferentiation and novel cell death forms such as ferroptosis, pyroptosis, and extracellular trap were reported. Discovery of novel pathological cellular landscapes provides a large number of therapeutic targets. On the other side, the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS burden. Stem cell- or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse effects. Given the complexity of pathological changes of AS, attempts to develop an almighty medicine based on single mechanisms could be theoretically challenging. In this review, the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical translation. The future challenges and improvements were also discussed.

Research advances in peptide‒drug conjugates

Peptide‒drug conjugates (PDCs) are drug delivery systems consisting of a drug covalently coupled to a multifunctional peptide via a cleavable linker. As an emerging prodrug strategy, PDCs not only preserve the function and bioactivity of the peptides but also release the drugs responsively with the cleavable property of the linkers. Given the ability to significantly improve the circulation stability and targeting of drugs in vivo and reduce the toxic side effects of drugs, PDCs have already been extensively applied in drug delivery. Herein, we review the types and mechanisms of peptides, linkers and drugs used to construct PDCs, and summarize the clinical applications and challenges of PDC drugs.

Chitosan Resin-Modified Glass Ionomer Cement Containing Epidermal Growth Factor Promotes Pulp Cell Proliferation with a Minimum Effect on Fluoride and Aluminum Release

The development of biomaterials that are able to control the release of bioactive molecules is a challenging task for regenerative dentistry. This study aimed to enhance resin-modified glass ionomer cement (RMGIC) for the release of epidermal growth factor (EGF). This RMGIC was formulated from RMGIC powder supplemented with 15% (w/w) chitosan at a molecular weight of either 62 or 545 kDa with 5% bovine serum albumin mixed with the same liquid component as the Vitrebond. EGF was added while mixing. ELISA was used to determine EGF release from the specimen immersed in phosphate-buffered saline at 1 h, 3 h, 24 h, 3 d, 1 wk, 2 wks, and 3 wks. Fluoride and aluminum release at 1, 3, 5, and 7 d was measured by electrode and inductively coupled plasma optical emission spectrometry. Pulp cell viability was examined through MTT assays and the counting of cell numbers using a Coulter counter. The RMGIC with 65 kDa chitosan is able to prolong the release of EGF for significantly longer than RMGIC for at least 3 wks due to its retained bioactivity in promoting pulp cell proliferation. This modified RMGIC can prolong the release of fluoride, with a small amount of aluminum also released for a limited time. This biomaterial could be useful in regenerating pulp-dentin complexes.

Progress and prospects of polysaccharide-based nanocarriers for oral delivery of proteins/peptides

The oral route has long been recognized as the most preferred route for drug delivery as it offers high patient compliance and requires minimal expertise. Unlike small molecule drugs, the harsh environment of the gastrointestinal tract and low permeability across the intestinal epithelium make oral delivery extremely ineffective for macromolecules. Accordingly, delivery systems that are rationally constructed with suitable materials to overcome barriers to oral delivery are exceptionally promising. Among the most ideal materials are polysaccharides. Depending on the interaction between polysaccharides and proteins, the thermodynamic loading and release of proteins in the aqueous phase can be realized. Specific polysaccharides (dextran, chitosan, alginate, cellulose, etc.) endow systems with functional properties, including muco-adhesiveness, pH-responsiveness, and prevention of enzymatic degradation. Furthermore, multiple groups in polysaccharides can be modified, which gives them a variety of properties and enables them to suit specific needs. This review provides an overview of different types of polysaccharide-based nanocarriers based on different kinds of interaction forces and the influencing factors in the construction of polysaccharide-based nanocarriers. Strategies of polysaccharide-based nanocarriers to improve the bioavailability of orally administered proteins/peptides were described. Additionally, current restrictions and future trends of polysaccharide-based nanocarriers for oral delivery of proteins/peptides were also covered.

The Oral Delivery System of Modified GLP-1 by Probiotics for T2DM

The glucagon-like peptide-1 (GLP-1) is a peptide with incretin activity and plays an important role in glycemic control as well as the improvement of insulin resistance in type 2 diabetes mellitus (T2DM). However, the short half-life of the native GLP-1 in circulation poses difficulties for clinical practice. To improve the proteolytic stability and delivery properties of GLP-1, a protease-resistant modified GLP-1 (mGLP-1) was constructed with added arginine to ensure the structural integrity of the released mGLP-1 in vivo. The model probiotic Lactobacillus plantarum WCFS1 was chosen as the oral delivery vehicle with controllable endogenous genetic tools driven for mGLP-1 secretory constitutive expression. The feasibility of our design was explored in db/db mice which showed an improvement in diabetic symptoms related to decreased pancreatic glucagon, elevated pancreatic β-cell proportion, and increased insulin sensitivity. In conclusion, this study provides a novel strategy for the oral delivery of mGLP-1 and further probiotic transformation.

Chitosan Nanogel with Mixed Food Plants and Its Relation to Blood Glucose in Type 2 Diabetes: A Systematic and Meta-Analysis Review of Observational Studies

This systematic review with metanalysis evaluated and analyzed the beneficial effects of certain plants food in type 2 diabetes (T2D) when consumed alone or in combination with chitosan. The main objective of the paper was to examine the relation of chitosan nanogel and mixed food plant (MFP) to control T2D. The databases included Medline, Scopus, PubMed, as well as Cochrane available between the month of January 1990 to January 2021. The eligibility criteria for selecting studies were case-controlled studies that included unripe plantain, bitter yam, okra, and chitosan either used-alone or in combination with non-specified food plants (NSFP). Two-fold autonomous critics retrieved the information required and evaluated the risk of bias of involved studies. Random-effect meta-analyses on blood glucose controls, were performed. Results of 18 studies included: seven that examined unripe plantains, one bitter yam, two okras, and eight chitosan, found regarding the decrease in blood glucose level. Meta-analysis of the results found a large proportion of I² values for all studies (98%), meaning heterogeneity. As a consequence, the combined effect sizes were not useful. Instead, prediction interval (PI) was used (mean difference 4.4 mg/dL, 95% PI -6.65 to 15.50 and mean difference 3.4 mg/dL, 95% PI -23.65 to 30.50) rather than the estimate of its confidence interval (CI). These studies were at 50% high risk of bias and 50% low risk of bias and there was judged to be an unclear risk of bias due to the insufficient information from the included study protocol (moderately low). The intervention lasted between three and 84 days, indicating potency and effectiveness of the intervention at both short and long durations. Due to the moderately low quality of the studies, the findings were cautiously interpreted. In conclusion, the current evidence available from the study does support the relation of chitosan with mixed unripe plantain, bitter yam and okra for the management of T2D. Further high-quality case-controlled animal studies are required to substantiate if indeed chitosan nanogel should be cross-linked with the specified food plant (SFP) for the management T2D.

Construction and Evaluation of Chitosan-Based Nanoparticles for Oral Administration of Exenatide in Type 2 Diabetic Rats

Oral delivery of therapeutic peptides has been a daunting challenge due to poor transport across the tight junctions and susceptibility to enzymatic degradation in the gastrointestinal tract. Numerous advancement in nanomedicine has been made for the effective delivery of protein and peptide. Owing to the superior performance of chitosan in opening intercellular tight junctions of epithelium and excellent mucoadhesive properties, chitosan-based nanocarriers have recently garnered considerable attention, which was formulated in this paper to orally deliver the GLP-1 drug (Exenatide). Against this backdrop, we used chitosan (CS) polymers to encapsulate the exenatide, sodium tripolyphosphate (TPP) as the cross-linking agent and coated the exterior with sodium alginate (ALG) to impart the stability in an acidic environment. The chitosan/alginate nanoparticles (CS-TPP-ALG) functioned as a protective exenatide carrier, realized efficient cellular uptake and controlled release, leading to a steady hypoglycemic effect and a good oral bioavailability in vivo. Trimethyl chitosan (TMC), a chitosan derivative with stronger positive electrical properties was additionally selected as a substitute for chitosan to construct the TMC-TPP-ALG nanoparticle, and its oral peptide delivery capacity was explored in terms of both characterization and pharmacodynamics studies. Overall, our study demonstrated that functional chitosan/alginate nanoparticles can protect proteins from enzymatic degradation and enhance oral absorption, which presents important research value and application prospects.

Emerging Theranostic Nanomaterials in Diabetes and Its Complications

Diabetes mellitus (DM) refers to a group of metabolic disorders that are characterized by hyperglycemia. Oral subcutaneously administered antidiabetic drugs such as insulin, glipalamide, and metformin can temporarily balance blood sugar levels, however, long-term administration of these therapies is associated with undesirable side effects on the kidney and liver. In addition, due to overproduction of reactive oxygen species and hyperglycemia-induced macrovascular system damage, diabetics have an increased risk of complications. Fortunately, recent advances in nanomaterials have provided new opportunities for diabetes therapy and diagnosis. This review provides a panoramic overview of the current nanomaterials for the detection of diabetic biomarkers and diabetes treatment. Apart from diabetic sensing mechanisms and antidiabetic activities, the applications of these bioengineered nanoparticles for preventing several diabetic complications are elucidated. This review provides an overall perspective in this field, including current challenges and future trends, which may be helpful in informing the development of novel nanomaterials with new functions and properties for diabetes diagnosis and therapy.

Chitosan for biomedical applications, promising antidiabetic drug delivery system, and new diabetes mellitus treatment based on stem cell

Since chitosan's excellent pharmacokinetic and chemical properties, it is an attractive and promising carbohydrate biopolymer in biomedical applications. Chitosan's beneficial function in the defense and propagation of pancreatic β cells, reducing hyperglycemia, and avoiding diabetes mellitus associated with impaired lipid metabolism has been demonstrated in several studies. Additionally, chitosan has also been used in various nanocarriers to deliver various antidiabetic drugs to reduce glucose levels. Herein, the first to provide the currently available potential benefits of chitosan in diabetes mellitus treatment focuses on chitosan-based nanocarriers for oral administration of various antidiabetic drugs nasal and subcutaneous passages. Moreover, chitosan is used to activate and deliver stem cells and differentiate them into cells similar to pancreatic beta cells as a new type of treatment for type one diabetes mellitus. The results of this review will be helpful in the development of promising treatments and better control of diabetes mellitus.

Nanoparticles: Promising Tools for the Treatment and Prevention of Myocardial Infarction

Despite several recent advances, current therapy and prevention strategies for myocardial infarction are far from satisfactory, owing to limitations in their applicability and treatment effects. Nanoparticles (NPs) enable the targeted and stable delivery of therapeutic compounds, enhance tissue engineering processes, and regulate the behaviour of transplants such as stem cells. Thus, NPs may be more effective than other mechanisms, and may minimize potential adverse effects. This review provides evidence for the view that function-oriented systems are more practical than traditional material-based systems; it also summarizes the latest advances in NP-based strategies for the treatment and prevention of myocardial infarction.

Preparation of chitosan from waste shrimp shells fermented with Paenibacillus jamilae BAT1

In this study, chitin extraction from shrimp shell powder (SSP) using locally isolated Paenibacillus jamilae BAT1 (GenBank: MN176658), the preparation of chitosan from the extracted chitin, and the characterization and biological activity (antimicrobial and antioxidant) of the prepared chitosan (PC) were investigated. It was determined that P. jamilae BAT1 did not have chitinase activity but showed high protease activity and protein removal potential. Optimum pH, shell concentration and incubation time for deproteinization were determined as 7.0, 60 g/L and 4 days, respectively. Addition of KH₂PO₄ or MgSO₄ did not affect chitin extraction and deproteinization yield. The maximum yields of deproteinization, demineralization and chitin extraction yields were 87.67, 41.95 and 24.5%, respectively. The viscosity-average molecular weight of PC was determined as 1.41 × 10⁵ g/mol. The deacetylation degree of PC (86%) was found to be higher that of commercial chitosan (CC) (78%). DPPH scavenging activity of PC (IC₅₀ 0.59 mg/mL) was higher than that of CC (IC₅₀ 3.72 mg/mL). PC was found to have higher antimicrobial activity against the bacteria E. coli and S. aureus and the yeast C. albicans when compared to CC. This is the first study on the use of the bacterium P. jamilae in biological chitin extraction.

Strategies to load therapeutics into polysaccharide-based nanogels with a focus on microfluidics: A review

Nowadays nanoparticles are increasingly investigated for the targeted and controlled delivery of therapeutics, as suggested by the high number of research articles (2400 in 2000 vs 8500 in 2020). Among them, almost 2% investigated nanogels in 2020. Nanogels or nanohydrogels (NGs) are nanoparticles formed by a swollen three-dimensional network of synthetic polymers or natural macromolecules such as polysaccharides. NGs represent a highly versatile nanocarrier, able to deliver a number of therapeutics. Currently, NGs are undergoing clinical trials for the delivery of anti-cancer vaccines. Herein, the strategies to load low molecular weight drugs, (poly)peptides and genetic material into polysaccharide NGs as well as to formulate NGs-based vaccines are summarized, with a focus on the microfluidics approach.

Peptide-Chitosan Engineered Scaffolds for Biomedical Applications

Peptides are signaling epitopes that control many vital biological events. Increased specificity, synthetic feasibility with concomitant lack of toxicity, and immunogenicity make this emerging class of biomolecules suitable for different applications including therapeutics, diagnostics, and biomedical engineering. Further, chitosan, a naturally occurring linear polymer composed of d-glucosamine and N-acetyl-d-glucosamine units, possesses anti-microbial, muco-adhesive, and hemostatic properties along with excellent biocompatibility. As a result, chitosan finds application in drug/gene delivery, tissue engineering, and bioimaging. Despite these applications, chitosan demonstrates limited cell adhesion and lacks biosignaling. Therefore, peptide-chitosan hybrids have emerged as a new class of biomaterial with improved biosignaling properties and cell adhesion properties. As a result, recent studies encompass increased application of peptide-chitosan hybrids as composites or conjugates in drug delivery, cell therapy, and tissue engineering and as anti-microbial material. This review discusses the recent investigations involving chitosan-peptide materials and uncovers various aspects of these interesting hybrid materials for biomedical applications.

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.

Initial Risk Assessment as part of the Quality by Design in peptide drug containing formulation development

Risk Assessment (RA) is the key element of the Quality by Design (QbD) approach recommended by the pharmaceutical regulatory bodies. This research paper aimed to implement the regulatory requirements, the QbD thinking and the RA from the first steps of the oral peptide formulation development. The authors intended to give a general recommendation about the application possibilities of this methodology, to demonstrate the risk factors and the required decision points. Later, this paper presents a concrete development in practice. This case study shows the QbD and RA based early phase development of the GLP 1 analog, Liraglutide, an antidiabetic peptide drug mainly used in the treatment of type 2 Diabetes Mellitus. The objective here was to design Liraglutide encapsulated polymeric nanoparticles for oral delivery and the progress of their RA based development is presented. In this case, the particle size, the encapsulation efficiency, and the drug loading were found as the most critical quality attributes, the polymer concentration, the drug concentration, the w2/o ratio, the stabilizer concentration and polymer type were identified by the criticality rating as having the greatest impact on the product quality among the critical material attributes, finally the sonication time and sonication power were selected as the most critical elements of the production process. The results showed the importance of the risk factor-focused development in the oral peptide pharmaceutical formulations, and underlined the importance of the profound planning phase even in such cases. The formulation of an oral peptide delivery system is associated with several risks, but their priority ranking helps to focus on the resources (human, financial, time) related to the final product quality aimed at.

Advances in micro- and nanotechnologies for the GLP-1-based therapy and imaging of pancreatic beta-cells

Therapies to prevent diabetes in particular the progressive loss of β-cell mass and function and/or to improve the dysregulated metabolism associated with diabetes are highly sought. The incretin-based therapy comprising GLP-1R agonists and DPP-4 inhibitors have represented a major focus of pharmaceutical R&D over the last decade. The incretin hormone GLP-1 has powerful antihyperglycemic effect through direct stimulation of insulin biosynthesis and secretion within the β-cells; it normalizes β-cell sensitivity to glucose, has an antiapoptotic role, stimulates β-cell proliferation and differentiation, and inhibits glucagon secretion. However, native GLP-1 therapy is inappropriate due to the rapid post-secretory inactivation by DPP-4. Therefore, incretin mimetics developed on the backbone of the GLP-1 or exendin-4 molecule have been developed to behave as GLP-1R agonists but to display improved stability and clinical efficacy. New formulations of incretins and their analogs based on micro- and nanomaterials (i.e., PEG, PLGA, chitosan, liposomes and silica) and innovative encapsulation strategies have emerged to achieve a better stability of the incretin, to improve its pharmacokinetic profile, to lower the administration frequency or to allow another administration route and to display fewer adverse effects. An important advantage of these formulations is that they can also be used at the targeted non-invasive imaging of the beta-cell mass. This review therefore focuses on the current state of these efforts as the next step in the therapeutic evolution of this class of antidiabetic drugs.

Molecular engineering solutions for therapeutic peptide delivery

Proteins and their interactions in and out of cells must be well-orchestrated for the healthy functioning and regulation of the body. Even the slightest disharmony can cause diseases. Therapeutic peptides are short amino acid sequences (generally considered <50 amino acids) that can naturally mimic the binding interfaces between proteins and thus, influence protein-protein interactions. Because of their fidelity of binding, peptides are a promising next generation of personalized medicines to reinstate biological harmony. Peptides as a group are highly selective, relatively safe, and biocompatible. However, they are also vulnerable to many in vivo pharmacologic barriers limiting their clinical translation. Current advances in molecular, chemical, and nanoparticle engineering are helping to overcome these previously insurmountable obstacles and improve the future of peptides as active and highly selective therapeutics. In this review, we focus on self-assembled vehicles as nanoparticles to carry and protect therapeutic peptides through this journey, and deliver them to the desired tissue.

Dietary Apostichopus japonicus Alleviates Diabetes Symptoms and Modulates Genes Expression in Kidney Tissues of db/db Mice

The effects of Apostichopus japonicus enzymatic hydrolysate on the regulation of dyslipidemia, pathoglycemia, and transcription changes in kidney tissues of db/db mice were evaluated. In this study, the symptoms of diabetes in db/db mice were alleviated after 10 weeks of treatments with low (db/db + LD group) and high dose (db/db + HD group) of Apostichopus japonicus enzymatic hydrolysate, and the high dose treatment showed a better antidiabetic effect. Compared with the db/db group, the fasting blood glucose levels (36.84 ± 7.82 vs 25.18 ± 6.84 mmol/L, P < 0.01), the urine glucose levels (45.44 ± 3.93 vs 22.66 ± 5.58 mmol/L, P < 0.01), and the serum insulin sensitivity index (-4.65 ± 0.43 vs -4.74 ± 0.75, P > 0.05) in the db/db + HD group were decreased, whereas the fasting plasma insulin (3.12 ± 1.08 vs 5.54 ± 1.82 μg/L, P < 0.01) and the serum insulin resistance index (5.01 ± 2.02 vs 5.96 ± 2.49, P < 0.05) were increased. Subsequently, the kidney transcription profiles were measured in the db/db group and db/db + HD group via microarray, and the results show that Apostichopus japonicus hydrolysate induced differential expression of 77 genes. Among these genes, the down-regulation of genes ntrK1 and ptpN5 played vital roles, as this effect induced the further down-regulation of neurotrophin tyrosine kinase, protein tyrosine phosphatase, and other transcription factors, which are involved in the classical mitogen-activated protein kinases (MAPK) and p38MAPK signaling pathways. The inhibited MAPK and p38MAPK signaling pathways are involved in glycometabolism and the control of lipid metabolism, and they regulate the occurrence and development of diabetic nephropathy.

Sustained-release study on Exenatide loaded into mesoporous silica nanoparticles: in vitro characterization and in vivo evaluation

BACKGROUND

Exenatide (EXT), the first glucagon-like peptide-1 receptor agonist, has been approved as an adjunctive therapy for patients with type 2 diabetes. Due to EXT's short half-life, EXT must be administrated by continuous subcutaneous (s.c.) injection twice daily. In previous studies, many studies on EXT loaded into polymer materials carriers for sustained release had been reported. However, these carriers have some defects, such as hydrophobicity, low surface energy, low mechanical strength, and poor chemical stability. Therefore, this study aims to develop a novel drug delivery system, which is EXT loaded into well-ordered hexagonal mesoporous silica structures (EXT-SBA-15), to control the sustainability of EXT.

METHODS

SBA-15 was prepared by hydrothermal method with uniform size. Morphology of SBA-15 was employed by transmission electron microscopy. The pore size of SBA-15 was characterized by N₂ adsorption-desorption isotherms. The in vitro drug release behavior and pharmacokinetics of EXT-SBA-15 were investigated. Furthermore, the blood glucose levels of diabetic mice were monitored after subcutaneous injection of EXT-Sol and EXT-SBA-15 to evaluate further the stable hypoglycemic effect of EXT-SBA-15.

RESULTS

EXT-SBA-15 showed a higher drug loading efficiency (15.2 ± 2.0%) and sustained-release features in vitro. In addition, pharmacokinetic studies revealed that the EXT-SBA-15 treatment group extended the half-life t _1/2(β) to 14.53 ± 0.70 h compared with that of the EXT solution (EXT-Sol) treatment group (0.60 ± 0.08 h) in vivo. Results of the pharmacodynamics study show that the EXT-SBA-15 treatment group had inhibited blood glucose levels below 20 mmol/L for 25 days, and the lowest blood glucose level was 13 mmol/L on the 10th day.

CONCLUSIONS

This study demonstrates that the EXT-SBA-15 delivery system can control the sustainability of EXT and contribute to improve EXT clinical use.

Oral delivery of diabetes peptides - Comparing standard formulations incorporating functional excipients and nanotechnologies in the translational context

While some orally delivered diabetes peptides are moving to late development with standard formulations incorporating functional excipients, the demonstration of the value of nanotechnology in clinic is still at an early stage. The goal of this review is to compare these two drug delivery approaches from a physico-chemical and a biopharmaceutical standpoint in an attempt to define how nanotechnology-based products can be differentiated from standard oral dosage forms for oral bioavailability of diabetes peptides. Points to consider in a translational approach are outlined to seize the opportunities offered by a better understanding of both the intestinal barrier and of nano-carriers designed for oral delivery.

ZOT-derived peptide and chitosan functionalized nanocarrier for oral delivery of protein drug

In this study, we developed a dual ligand functionalized pluronic-based nanocarrier (NC) for oral delivery of insulin. Chitosan and zonula occludins toxin (ZOT)-derived, tight junction opening peptide were conjugated to NC to increase the permeability of loaded insulin across the small intestine through the paracellular pathway. Surface functionalized NC, either by chitosan or peptide, could modulate the tight junction (TJ) integrity in contrast to no effect of unmodified NC, as evidenced by the change in transepithelial electrical resistance (TEER) and immunostaining of Claudin-4, a tight junction marker, in Caco-2 cell monolayer. On the other hand, dual ligand (chitosan and peptide) functionalized NC significantly further increased the permeation of insulin across Caco-2 cell monolayer. More importantly, insulin loaded, dual ligand functionalized NC could increase the plasma insulin level and efficiently regulate the glycemic response for a prolonged period of time (∼1 day) upon oral administration to diabetic rats, whereas delivery of insulin by single ligand functionalized NCs, either by chitosan or peptide, as well as by unmodified NC and free insulin, could not induce the effective regulation of the blood glucose level. The use of fluorescence dye labeled insulin (FITC-insulin) and Cy5.5 labeled NC revealed that both insulin and dual ligand functionalized NC were adequately penetrated across the whole intestine villi in contrast to limited adsorption of insulin and NC mainly onto the epithelial surface of the intestine for single ligand functionalized NCs. These results suggest that dual conjugation of ZOT-derived peptide and chitosan is a promising approach to functionalize the surface of nanocarrier for oral delivery of protein drugs.

Formulation of essential oil-loaded chitosan–alginate nanocapsules

Naturally occurring polymers such as alginate (AL) and chitosan (CS) are widely used in biomedical and pharmaceutical fields in various forms such as nanoparticles, capsules, and emulsions. These polymers have attractive applications in drug delivery because of their biodegradability, biocompatibility, and nontoxic nature. The pharmaceutical applications of essential oils such as turmeric oil and lemongrass oil are well-known, and their active components, arturmerone and citral, respectively, are known for their antibacterial, antifungal, antioxidant, antimutagenic, and anticarcinogenic properties. However, these essential oils are unstable, volatile, and insoluble in water, which limits their use for new formulations. Therefore, this study focuses on developing a CS–AL nanocarrier for the encapsulation of essential oils. The effects of process parameters such as the effect of heat and the concentrations of AL and CS were investigated. Various physicochemical characterization techniques such as scanning electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy were performed. Results of characterization studies showed that 0.3 mg/mL AL and 0.6 mg/mL CS produced minimum-sized particles (<300 nm) with good stability. It was also confirmed that the oil-loaded nanocapsules were hemocompatible, suggesting their use for future biomedical and pharmaceutical applications. Furthermore, the antiproliferative activity of turmeric oil- and lemongrass oil-loaded nanocapsules was estimated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in A549 cell lines and it was found that both the nanoformulations had significant antiproliferative properties than the bare oil.

Micro/nanofabricated platforms for oral drug delivery

The oral route of drug administration is most preferred due to its ease of use, low cost, and high patient compliance. However, the oral uptake of many small molecule drugs and biotherapeutics is limited by various physiological barriers, and, as a result, drugs suffer from issues with low solubility, low permeability, and degradation following oral administration. The flexibility of micro- and nanofabrication techniques has been used to create drug delivery platforms designed to address these barriers to oral drug uptake. Specifically, micro/nanofabricated devices have been designed with planar, asymmetric geometries to promote device adhesion and unidirectional drug release toward epithelial tissue, thereby prolonging drug exposure and increasing drug permeation. Furthermore, surface functionalization, nanotopography, responsive drug release, motion-based responses, and permeation enhancers have been incorporated into such platforms to further enhance drug uptake. This review will outline the application of micro/nanotechnology to specifically address the physiological barriers to oral drug delivery and highlight technologies that may be incorporated into these oral drug delivery systems to further enhance drug uptake.

A review of biodegradable polymeric systems for oral insulin delivery

Currently, repeated routine subcutaneous injections of insulin are the standard treatment for insulin-dependent diabetic patients. However, patients' poor compliance for injections often fails to achieve the stable concentration of blood glucose. As a protein drug, the oral bioavailability of insulin is low due to many physiological reasons. Several carriers, such as macromolecules and liposomes have been used to deliver drugs in vivo. In this review article, the gastrointestinal barriers of oral insulin administration are described. Strategies for increasing the bioavailability of oral insulin, such absorption enhancers, enzyme inhibitors, enteric coatings are also introduced. The potential absorption mechanisms of insulin-loaded nanoparticles across the intestinal epithelium, including intestinal lymphatic route, transcellular route and paracellular route are discussed in this review. Natural polymers, such as chitosan and its derivates, alginate derivatives, γ-PGA-based materials and starch-based nanoparticles have been exploited for oral insulin delivery; synthetic polymers, such as PLGA, PLA, PCL and PEA have also been developed for oral administration of insulin. This review focuses on recent advances in using biodegradable natural and synthetic polymers for oral insulin delivery along with their future prospects.

A proton-responsive ensemble using mesocellular foam supports capped with N,O-carboxymethyl chitosan for controlled release of bioactive proteins

A novel pH-responsive mesocellular foam-based nanocarrier was fabricated by the covalent assembly of a water-soluble N,O-carboxymethyl chitosan via the crosslinking of GPTMS for controlled release of proteins and maintaining their bioactivity.

Overcoming the challenges in administering biopharmaceuticals: formulation and delivery strategies

The formulation and delivery of biopharmaceutical drugs, such as monoclonal antibodies and recombinant proteins, poses substantial challenges owing to their large size and susceptibility to degradation. In this Review we highlight recent advances in formulation and delivery strategies--such as the use of microsphere-based controlled-release technologies, protein modification methods that make use of polyethylene glycol and other polymers, and genetic manipulation of biopharmaceutical drugs--and discuss their advantages and limitations. We also highlight current and emerging delivery routes that provide an alternative to injection, including transdermal, oral and pulmonary delivery routes. In addition, the potential of targeted and intracellular protein delivery is discussed.

Design of chitosan-based nanoformulations for efficient intracellular release of active compounds

The use of chitosan-based nanocarriers to transport active compounds gained an increasing attention in drug delivery. Intracellular delivery, with efficient intracellular release, become an important design considerations in chitosan based nanoformlations. Internal stimuli-responsive nanoformulations are designed to release active compounds after internalization based on certain internal stimuli like pH, redox potential and enzymes. Futhermore, nondestructive pathways may provide a nondigestive compartment for active compounds transport, which can protect the encapsulated agents from possible lysosomal degradation, thereby realizing release agents safely. This review gives a brief overview about the chitosan-based nanoformulations for efficient intracellular cargo release, including internal stimuli-responsive nanoformulations and nondestructive pathways based nanoformulations: design strategies and applications. The present problems and a possible future perspective related them are also discussed.

Photoluminescence from Chitosan for Bio-Imaging

Photoluminescent behaviours of chitosan were investigated. Photoluminescence can be observed from aqueous solution of chitosan, and CO2 treatment can improve the intensity of photoluminescence. The maximum emission is obtained with an excitation at ~336 nm, and the emission wavelength is dependent on the excitation wavelength with a longer excitation wavelength leading to a longer emission wavelength. The chemistry of chitosan before and after CO2 treatment was characterised; and the results reflect that carbamato anion is formed via the reaction between the amines and CO2, and is the fluorophore of the photoluminescence observed. Furthermore, chitosan was applied as an imaging agent for imaging MCF-7 cells using confocal microscopy. Blue and bright green imaging of the cells can be obtained via tuning the excitation and emission wavelength. Together with a low cytotoxicity reflected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide evaluation, fluorescent chitosan is promising for bio-imaging.

Aerosolized GLP-1 for treatment of diabetes mellitus and irritable bowel syndrome

Diabetes is a global burden and the prevalence of the disease, in particular diabetes mellitus type 2 is rapidly increasing worldwide. After introduction of insulin into clinical therapy about 90 years ago a major number of pharmaceuticals has been developed for treatment of diabetes mellitus type 2. One of these, the incretin glucagon-like peptide 1 (GLP-1), like insulin, needs subcutaneous administration causing inconvenience to patients. However, administration of GLP-1 plays also a role for treatment of irritable bowel syndrome (IBS). To improve patient convenience inhaled insulin (Exubera(®)) was developed and approved but failed market acceptance some years ago. Recently, another inhalative insulin (Afrezza(®)) received market approval and GLP-1 may serve as another candidate drug for inhalative administration. This review analyzes the current literature investigating alternative administration of GLP-1 and GLP-1 analogs focusing on inhalation. Several formulations for inhalative administration of GLP-1 and analogs were investigated in animal studies, whereas there are only few clinical data. However, feasibility of GLP-1 inhalation has been shown and should be further investigated as such type of drug administration may serve for improvement of therapy in patients with diabetes mellitus or irritable bowel syndrome.