Preparation and characterization of glycoprotein-resistant starch complex as a coating material for oral bioadhesive microparticles for colon-targeted polypeptide delivery

Starch-based materials for drug delivery in the gastrointestinal tract-A review

Starch is a natural copolymer with unique physicochemical characteristics. Historically, it has been physically, chemically, or enzymatically modified to obtain ad-hoc functional properties for its use in different applications. In this context, the use of starch-based materials in drug delivery systems (DDSs) has gained great attention mainly because it is cheap, biodegradable, biocompatible, and renewable. This paper reviews the state of the art in starch-based materials design for their use in drug-controlled release with internal stimulus responsiveness; i.e., pH, temperature, colonic microbiota, or enzymes; specifically, those orally administered for its release in the gastrointestinal tract (GIT). Physical-chemical principles in the design of these materials taking into account their response to a particular stimulus are discussed. The relationship between the type of DDSs structure, starch modification routes, and the corresponding drug release profiles are systematically analyzed. Furthermore, the challenges and prospects of starch-based materials for their use in stimulus-responsive DDSs are also debated.

Multi-responsive starch-based nanocapsules for colon-targeting delivery of peptides: In vitro and in vivo evaluation

Colon-targeting delivery of insulin is surging great interests in revolutionizing diabetes. Herein, insulin-loaded starch-based nanocapsules developed by layer-by-layer self-assembly technology were rationally structured. Interactions between starches and the structural changes of the nanocapsules were unraveled to understand in vitro and in vivo insulin release properties. By increasing the deposition layers of starches, the structural compactness of nanocapsules increased and in turn retarded insulin release in the upper gastrointestinal tract. Spherical nanocapsules deposited at least five layers of starches could deliver insulin to the colon in a high efficiency according to the in vitro and in vivo insulin release performance. The underlying mechanism of the insulin colon-targeting release should ascribe to the suitable changes in compactness of the nanocapsules and the interactions between deposited starches after multi-response to the changes in pH, time and enzymes in gastrointestinal tract. Starch molecules interacted with each other much stronger at the intestine than that at the colon, which guaranteed a compact structure in the intestine but a loose structure in the colon for the colon-targeting nanocapsules. It suggested that rather than controlling the deposition layer of the nanocapsules, controlling the interaction between starches could also regulate the structures of the nanocapsules for colon-targeting delivery system.

Recent Progress in Microencapsulation of Active Peptides-Wall Material, Preparation, and Application: A Review

Being a natural active substance with a wide variety of sources, easy access, significant curative effect, and high safety, active peptides have gradually become one of the new research directions in food, medicine, agriculture, and other fields in recent years. The technology associated with active peptides is constantly evolving. There are obvious difficulties in the preservation, delivery, and slow release of exposed peptides. Microencapsulation technology can effectively solve these difficulties and improve the utilization rate of active peptides. In this paper, the commonly used materials for embedding active peptides (natural polymer materials, modified polymer materials, and synthetic polymer materials) and embedding technologies are reviewed, with emphasis on four new technologies (microfluidics, microjets, layer-by-layer self-assembly, and yeast cells). Compared with natural materials, modified materials and synthetic polymer materials show higher embedding rates and mechanical strength. The new technology improves the preparation efficiency and embedding rate of microencapsulated peptides and makes the microencapsulated particle size tend to be controllable. In addition, the current application of peptide microcapsules in different fields was also introduced. Selecting active peptides with different functions, using appropriate materials and efficient preparation technology to achieve targeted delivery and slow release of active peptides in the application system, will become the focus of future research.

Controlling the Interaction between Starchy Polyelectrolyte Layers for Adjusting Protein Release from Nanocapsules in a Simulated Gastrointestinal Tract

Orally delivered bioactive proteins face great challenges in the harsh environment of the upper gastrointestinal tract (GIT) in the field of functional foods based on bioactive proteins. Therefore, it is necessary to design carriers and delivery systems that have the potential to overcome the problem of lower bioaccessibility for protein cargoes. In this work, we present a starchy oral colon-targeting delivery system, capable of improving the release profile of the protein cargoes. The starchy oral colon-targeting delivery system was fabricated using layer-by-layer assembly of starchy polyelectrolytes (carboxymethyl anionic starch and spermine cationic starch) onto the surface of protein nanoparticles via electrostatic interaction. The dynamic change in the interaction between the starchy polyelectrolytes affected the shell aggregation structure and determined the release kinetics of nanocapsules in the GIT. Specifically, the stronger interactions between the starchy layers and the thicker and more compact shell layer kept the nanocapsule intact in the simulated gastric and intestinal fluids, better-protecting the protein from degradation by digestive fluids, thus avoiding the burst release effect in the SGF and SIF. However, the nanocapsule could quickly swell with the decreasing molecular interactions between starchy polyelectrolytes, increasing protein release (63.61%) in the simulated colonic fluid. Therefore, release behaviors of protein cargoes could be appropriately controlled by adjusting the number of deposited layers of pH-sensitive starchy polyelectrolytes on the nanocapsule. This could improve the bioaccessibility of oral targeted delivery of bioactive proteins to the colon.

Hyaluronic Acid Coated Chitosan Nanoparticles for Insulin Oral Delivery: Fabrication, Characterization and Hypoglycemic Ability

Oral administration of insulin faces multiple biological challenges, such as varied digestive environments, mucin exclusion and low epithelial cells absorption. In the present study, a hyaluronic acid coated chitosan nanoparticle delivery system was fabricated for insulin oral delivery. It is hypothesized that the developed nanoparticles will protect insulin from digestive degradation, promote intestinal epithelial cell absorption and exert strong in vivo hyperglycemic ability. Nanoparticles formulated by chitosan (CS) and sodium tripolyphosphate (TPP) was optimized to form the core nanoparticles (CNP). Hyaluronic acid (HA) was further applied to coat CNP (HCP) to improve stability, reduce enzymatic degradation and promote absorption of insulin. HCP promoted insulin uptake by Caco-2 cells, absorbed less mucin and improved intestinal absorption. Moreover, in vivo test demonstrated that oral administration of insulin-loaded HCP exerts strong and continuous hyperthermia effect (with PA of 13.8%). In summary, HCP is a promising delivery platform for insulin oral administration in terms of protecting insulin during digestion, facilitating its absorption and ultimately promoting its oral bioavailability. This article is protected by copyright. All rights reserved.

Starch Nanoparticles for Enhancement of Oral Bioavailability of a Newly Synthesized Thienopyrimidine Derivative with Anti-Proliferative Activity Against Pancreatic Cancer

Purpose

This research aimed to improve water solubility and oral bioavailability of a newly synthesized thienopyrimidine derivative (TPD) with anti-pancreatic cancer activity by loading on starch nanoparticles (SNPs).

Methods

TPD was synthesized, purified and its ADME behavior was predicted using Swiss ADME software. A UV spectroscopy method was developed and validated to measure TPD concentration at various dosage forms. SNPs loaded with TPD (SNPs-TPD) were prepared, characterized for particle size, polydispersity index, zeta potential, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), entrapment efficiency, in-vitro release, and in-vivo animal study.

Results

The Swiss ADME results showed that TPD can be administered orally; however, it has low oral bioavailability (0.55) and poor water solubility. The significant regression coefficient of the calibration curve (r² = 0.9995), the precision (%RSD < 0.5%) and the accuracy (99.46−101.72%) confirmed the efficacy of the developed UV method. SNPs-TPD had a spherical monodispersed (PDI= 0.12) shape, nanoparticle size (22.98 ± 4.23) and good stability (−21 ± 4.72 mV). Moreover, FT-IR and DSC revealed changes in the physicochemical structure of starch resulting in SNPs formation. The entrapment efficiency was 97% ± 0.45%, and the in-vitro release showed that the SNPs enhanced the solubility of the TPD. The in-vivo animal study and histopathology showed that SNPs enhanced the oral bioavailability of TPD against solid Ehrlich carcinoma.

Conclusion

SNPs-TPD were superior in drug solubility and oral bioavailability than those obtained from TPD suspension.

Oral peptide delivery: challenges and the way ahead

Peptides and proteins have emerged as potential therapeutic agents and, in the search for the best treatment regimen, the oral route has been extensively evaluated because of its non-invasive and safe nature. The physicochemical properties of peptides and proteins along with the hurdles in the gastrointestinal tract (GIT), such as degrading enzymes and permeation barriers, are challenges to their delivery. To address these challenges, several conventional and novel approaches, such as nanocarriers, site-specific and stimuli specific delivery, are being used. In this review, we discuss the challenges to the oral delivery of peptides and the approaches used to tackle these challenges.

The role of polysaccharides from natural resources to design oral insulin micro- and nanoparticles intended for the treatment of Diabetes mellitus: A review

Oral administration of insulin (INS) would represent a revolution in the treatment of diabetes, considering that this route mimics the physiological dynamics of endogenous INS. Nano- and microencapsulation exploiting the advantageous polysaccharides properties has been considered an important technological strategy to protect INS against harsh conditions of gastrointestinal tract, in the same time that improve the permeability via transcellular and/or paracellular pathways, safety and in some cases even selectivity for targeting delivery of INS. In fact, some polysaccharides also give to the systems functional properties such as pH-responsiveness, mucoadhesiveness under specific physiological conditions and increased intestinal permeability. In general, all polysaccharides can be functionalized with specific molecules becoming more selective to the cells to which INS is delivered. The present review highlights the advances in the past 10 years on micro- and nanoencapsulation of INS exploiting the unique natural properties of polysaccharides, including chitosan, starch, alginate, pectin, and dextran, among others.

The in vivo digestibility study of banana flour with high content of resistant starch at different ripening stages

Resistant starch, a functional food ingredient, can improve the nutritional value of food products. In this study, the in vitro digestibility of starch from banana flour at four ripening stages was evaluated. The result showed that the resistant starch content of banana flour at ripening stage 1 was up to 81%. Furthermore, to explore the effect of resistant starch in the body, the in vivo digestibility of banana flour was investigated. The intake of banana flour at ripening stage 1 resulted in a nearly 70% decrease in the homeostasis model assessment of insulin resistance value, compared to that of the model group. By contrast, the genes related to glucokinase were upregulated by 66%, and the expression level of the insulin receptor gene was increased by more than 1.5 times that of the model group. Thus, natural banana flour has potential for controlling type 2 diabetes mellitus.

Insights into the relationship between structure and rheological properties of starch gels in hot-extrusion 3D printing

This work investigated the relationship between structure, rheological properties and 3D printability of starch. For this purpose, the structural evolution of various starch gels at different concentrations and printing temperatures was systematically studied. The mechanical strength (G', τ_y) and extrudability (τ_f) of CS and RS gels were used to determine its 3D printability. Furthermore, G', τ_y and τ_f were closely related to the structure of starch and starch gel network. Ascribing to compact and stable gel network, CS samples with 20% concentration at 70-75 °C printing temperature and RS samples with 15-20% concentration at 75-80 °C printing temperature displayed preferable printing values (G', τ_y and τ_f), indicating the suitability for HE-3DP. RS samples exhibited higher mechanical strength than CS samples and were more suitable to print owing to the formation of new crystal structure. Overall, this work provided important information for HE-3DP based foods with good printability.

Oral delivery of insulin with intelligent glucose-responsive switch for blood glucose regulation

BACKGROUND

The traditional treatment for diabetes usually requires frequent insulin injections to maintain normoglycemia, which is painful and difficult to achieve blood glucose control.

RESULTS

To solve these problems, a non-invasive and painless oral delivery nanoparticle system with bioadhesive ability was developed by amphipathic 2-nitroimidazole-L-cysteine-alginate (NI-CYS-ALG) conjugates. Moreover, in order to enhance blood glucose regulation, an intelligent glucose-responsive switch in this nanoparticle system was achieved by loading with insulin and glucose oxidase (GOx) which could supply a stimulus-sensitive turnover strategy. In vitro tests illustrated that the insulin release behavior was switched "ON" in response to hyperglycemic state by GOx catalysis and "OFF" by normal glucose levels. Moreover, in vivo tests on type I diabetic rats, this system displayed a significant hypoglycemic effect, avoiding hyperglycemia and maintaining a normal range for up to 14 h after oral administration.

CONCLUSION

The stimulus-sensitive turnover strategy with bioadhesive oral delivery mode indicates a potential for the development of synthetic GR-NPs for diabetes therapy, which may provide a rational design of proteins, low molecular drugs, as well as nucleic acids, for intelligent releasing via the oral route.

Enhanced oral absorption of insulin using colon-specific nanoparticles co-modified with amphiphilic chitosan derivatives and cell-penetrating peptides

In this study, amphipathic chitosan derivative (ACS) and cell-penetrating peptide (CPP) co-modified colon-specific nanoparticles (CS-CPP NPs) were prepared and evaluated to improve the oral bioavailability of protein and peptide drugs. ACS modification was harnessed to protect CPPs from degradation in the stomach and small intestine after oral administration and achieve colon-specific drug delivery. After CS-CPP NPs reached the colon, ACSs on the surface of the NPs were gradually degraded and CPPs were exposed to bring into play the penetration efficacy in the colon epithelium. Herein, we synthesized four types of ACSs (TOCS, TDCS, TPCS and TSCS) and adopted three types of CPPs (Tat, Penetratin and R8) to prepare NPs (TOCS-Tat NPs, TDCS-Tat NPs, TPCS-Tat NPs, TSCS-Tat NPs, TDCS-Pen NPs and TDCS-R8 NPs). The study of the protective effects of ACS upon Tat showed that the modification of ACS exerted favourable protection upon Tat in the stomach and small intestine. ACS degradation in the colon was indirectly determined in the viscosity method, which indicated that ACS could be gradually degraded in the colon. Using Caco-2 cell monolayers as cell models, it was found that the cellular uptake amount and transcellular transportation performance of CS-CPP NPs were much enhanced compared with those of TDCS NPs and PVA NPs. With Bama mini-pigs as animal models, the pharmacodynamic study demonstrated that the hypoglycemic effect for insulin-loaded TDCS-Tat NPs was more significant than that for TDCS NPs, lowering the blood glucose by 40%. The pharmacokinetic study indicated that the AUC and Cmax for TDCS-Tat NPs were respectively increased by 1.45 times and 1.82 times compared with those of TDCS NPs. In conclusion, CS-CPP NPs as vehicles for colon-specific drug delivery systems may be an efficient approach to improve the oral absorption of protein and peptide drugs.

Comparative study on the chemical composition, anthocyanins, tocopherols and carotenoids of selected legumes

Twenty-nine legumes were assessed for their nutritional and phytochemical compositions. Soybean and black soybean had the highest protein contents (34.05-42.65 g/100 g DW, dry weight of legumes), particularly being a rich source of lysine (1.78-2.23 g/100 g DW. Soybean and black soybean had the highest fat contents (14.13-22.19 g/100 g DW). Broad beans had the highest unsaturated fatty acids (83.57-89.01 g/100 g fatty acid), particularly rich in α-linolenic and linoleic acid. The highest and the lowest dietary fiber were found in red kidney beans (35.36 g/100 g DW) and mung beans (22.77 g/100 g DW), respectively. Except for soybean and white kidney bean, 6 major anthocyanins in the legumes samples were identified. The soybean contained the highest total tocopherols content (90.40-120.96 μg/g dry weight of beans), followed by black soybean (66.13-100.76 μg/g DW). The highest carotenoids were found in lentils (4.53-21.34 μg/g DW) and red kidney beans (8.29-20.95 μg/g DW).

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.

Fabrication and characterization of complex nanoparticles based on carboxymethyl short chain amylose and chitosan by ionic gelation

The combination of carboxymethyl short chain amylose with chitosan could be considered as a candidate for oral delivery of insulin.

Microparticles, microcapsules and microspheres: A review of recent developments and prospects for oral delivery of insulin

Diabetes mellitus is a chronic metabolic health disease affecting the homeostasis of blood sugar levels. However, subcutaneous injection of insulin can lead to patient non-compliance, discomfort, pain and local infection. Sub-micron sized drug delivery systems have gained attention in oral delivery of insulin for diabetes treatment. In most of the recent literature, the terms "microparticles" and "nanoparticle" refer to particles where the dimensions of the particle are measured in micrometers and nanometers respectively. For instance, insulin-loaded particles are defined as microparticles with size larger than 1 μm by most of the research groups. The size difference between nanoparticles and microparticles proffers numerous effects on the drug loading efficiency, aggregation, permeability across the biological membranes, cell entry and tissue retention. For instance, microparticulate drug delivery systems have demonstrated a number of advantages including protective effect against enzymatic degradation, enhancement of peptide stability, site-specific and controlled drug release. Compared to nanoparticulate drug delivery systems, microparticulate formulations can facilitate oral absorption of insulin by paracellular, transcellular and lymphatic routes. In this article, we review the current status of microparticles, microcapsules and microspheres for oral administration of insulin. A number of novel techniques including layer-by-layer coating, self-polymerisation of shell, nanocomposite microparticulate drug delivery system seem to be promising for enhancing the oral bioavailability of insulin. This review draws several conclusions for future directions and challenges to be addressed for optimising the properties of microparticulate drug formulations and enhancing their hypoglycaemic effects.

Preparation and Characterization of Protein-Loaded Electrospun Fiber Mat and Its Release Kinetics

For the enhancement of protein's bioavailability, a specific delivery system was developed by coaxial electrospinning. Bovine serum albumin (BSA) was used as protein model, and the core-sheath fiber mat was fabricated using sodium alginate as shell layer and the BSA-loaded chitosan nanoparticle that was prepared previously as core layer. By optimizing electrospinning parameters, uniform fibers with diameters ranging from 200-600 nm were obtained, and transmission electron microscopy and confocal laser scanning microscopy revealed their core-sheath structures. Fourier transform infrared spectroscopy (FTIR) analysis demonstrated that there existed molecular interaction between components, which enhanced the mat's thermal stability and mechanic property. It was found that the predominant release mechanism of BSA from fiber mat was erosion, and little change occurred in the secondary structure of encapsulated BSA indicated by FTIR and circular dichroism analysis. The study shows that the obtained fiber mat is a potential delivery system for protein.

Digestibility and supramolecular structural changes of maize starch by non-covalent interactions with gallic acid

The synergistic effect of starch–GA complexes with more ordered multi-scale structures and the released GA inhibition decrease starch enzymatic digestibility.

Oral absorption of peptides and nanoparticles across the human intestine: Opportunities, limitations and studies in human tissues

In this contribution, we review the molecular and physiological barriers to oral delivery of peptides and nanoparticles. We discuss the opportunities and predictivity of various in vitro systems with special emphasis on human intestine in Ussing chambers. First, the molecular constraints to peptide absorption are discussed. Then the physiological barriers to peptide delivery are examined. These include the gastric and intestinal environment, the mucus barrier, tight junctions between epithelial cells, the enterocytes of the intestinal epithelium, and the subepithelial tissue. Recent data from human proteome studies are used to provide information about the protein expression profiles of the different physiological barriers to peptide and nanoparticle absorption. Strategies that have been employed to increase peptide absorption across each of the barriers are discussed. Special consideration is given to attempts at utilizing endogenous transcytotic pathways. To reliably translate in vitro data on peptide or nanoparticle permeability to the in vivo situation in a human subject, the in vitro experimental system needs to realistically capture the central aspects of the mentioned barriers. Therefore, characteristics of common in vitro cell culture systems are discussed and compared to those of human intestinal tissues. Attempts to use the cell and tissue models for in vitro-in vivo extrapolation are reviewed.

Polymeric nanoparticles for colon cancer therapy: overview and perspectives

Colorectal cancer (CRC) is the third-most common malignant tumour and is associated with high morbidity and mortality worldwide.