An overview of natural polymers for oral insulin delivery

Self-assembly pH-sensitive polyelectrolyte complex co-delivers niclosamide and colistin to overcome colistin resistance in bacterial infections

Polyelectrolyte complexes (PECs) provided new opportunities for drug-controlled release systems and had the potential to address the challenges during the effective oral delivery of colistin and niclosamide. Here, an innovative pH-sensitive PEC for the oral co-delivery of colistin and niclosamide (CS/AL-PECs@COL/NIC) was developed, which was self-assembled through electrostatic interaction by an optimized double-emulsion method from two oppositely charged nanoparticles (chitosan-coated nanoparticles and alginate-coated nanoparticles). The CS/AL-PECs@COL/NIC exhibited pH sensitivity, formed a tight cross-linked structure in the gastric acid environment, effectively slowing down the release of the loaded drugs (colistin and niclosamide), and transformed into a loose structure in the neutral environment of the intestine, facilitating the stable release of the loaded drugs. Importantly, the CS/AL-PECs@COL/NIC had good in vivo antibacterial activity against E. coli infection and alleviated the inflammation and intestinal damage caused by bacterial infection in the mouse intestinal infection model. Both in vitro and in vivo studies indicated that the CS/AL-PECs@COL/NIC had good biocompatibility and good palatability. In particular, the oral administration of an effective dose of CS/AL-PECs@COL/NIC did not cause intestinal flora disorder, which had an advantage over colistin treatment. Thus, the prepared CS/AL-PECs@COL/NIC may contribute to treating colistin-resistant bacterial infections as a biocompatible oral administration.

Latest advancements and trends in biomedical polymers for disease prevention, diagnosis, treatment, and clinical application

Biomedical polymers are at the forefront of medical advancements, offering innovative solutions in disease prevention, diagnosis, treatment, and clinical use due to their exceptional physicochemical properties. This review delves into the characteristics, classification, and preparation methods of these polymers, highlighting their diverse applications in drug delivery, medical imaging, tissue engineering, and regenerative medicine. We present a thorough analysis of the recent advancements in biomedical polymer research and their clinical applications, acknowledging the challenges that remain, such as immune response management, controlled degradation rates, and mechanical property optimization. Addressing these issues, we explore future directions, including personalization and the integration of nanotechnology, which hold significant potential for further advancing the field. This comprehensive review aims to provide a deep understanding of biomedical polymers and serve as a valuable resource for the development of innovative polymer materials in both fundamental research and clinical practice.

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

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

Biodegradable Polymers for Micro Elastofluidics

Micro elastofluidics is an emerging research field that encompasses characteristics of conventional microfluidics and fluid-structure interactions. Micro elastofluidics is expected to enable practical applications, for instance, where direct contact between biological samples and fluid handling systems is required. Besides design optimization, choosing a proper material is critical to the practical use of micro elastofluidics upon interaction with biological interface and after its functional lifetime. Biodegradable polymers are one of the most studied materials for this purpose. Micro elastofluidic devices made of biodegradable polymers possess exceptional mechanical elasticity, excellent bio compatibility, and structural degradability into non-toxic products. This article provides an insightful and systematic review of the utilization of biodegradable polymers in digital and continuous-flow micro elastofluidics.

Encapsulation of polyketide colorants in chitosan and maltodextrin microparticles

This study aimed to encapsulate Talaromyces amestolkiae colorants in maltodextrin and chitosan microparticles using the spraydrying technique and to evaluate the biopolymers' capacities to protect the fungal colorant against temperature (65 °C) and extreme pH (2.0 and 13.0). The compact microparticles exhibited smooth or indented surfaces with internal diameters ranging between 2.58-4.69 μm and ζ ~ -26 mV. The encapsulation efficiencies were 86 % and 56 % for chitosan and maltodextrin microparticles, respectively. The shifted endothermic peaks of the free colorants indicated their physical stabilization into microparticles. The encapsulated colorants retained most of their absorbance (compared to the 0 h) even after 25 days at 65 °C. Contrary, the free colorant presented almost no absorbance after 1 day under the same conditions. Colorants in chitosan and maltodextrin matrices also partially maintained their colorimetric and fluorometric properties at acidic pH. However, only maltodextrin improved the resistance of the red colorant to alkaline environments. For the first time, the potential of polysaccharide-based microparticles to preserve polyketide colorants was demonstrated using 3D fluorescence. Therefore, this study demonstrated an alternative in developing functional products with natural color additives.

Cracking the intestinal lymphatic system window utilizing oral delivery vehicles for precise therapy

Oral administration is preferred over other drug delivery methods due to its safety, high patient compliance, ease of ingestion without discomfort, and tolerance of a wide range of medications. However, oral drug delivery is limited by the poor oral bioavailability of many drugs, caused by extreme conditions and absorption challenges in the gastrointestinal tract. This review thoroughly discusses the targeted drug vehicles to the intestinal lymphatic system (ILS). It explores the structure and physiological barriers of the ILS, highlighting its significance in dietary lipid and medication absorption and transport. The review presents various approaches to targeting the ILS using spatially precise vehicles, aiming to enhance bioavailability, achieve targeted delivery, and reduce first-pass metabolism with serve in clinic. Furthermore, the review outlines several methods for leveraging these vehicles to open the ILS window, paving the way for potential clinical applications in cancer treatment and oral vaccine delivery. By focusing on targeted drug vehicles to the ILS, this article emphasizes the critical role of these strategies in improving therapeutic efficacy and patient outcomes. Overall, this article emphasizes the critical role of targeted drug vehicles to the ILS and the potential impact of these strategies on improving therapeutic efficacy and patient outcomes.

Controlled and Targeted Drug Delivery Using Smart Nanovectors

The conventional drug delivery systems have several limitations, such as the high frequency of administration, several off-target effects, and the need for tissue specificity. Recently, smart drug shuttles have emerged, and the nano applications provided a new opportunity for advancing the drug delivery system to become tissue targeted and decrease the frequency of administration. The recent development of nanovectors as drug carriers has gone through several steps of evolution that ended with the development of logic-embedded nanovectors. Here, we summarize the different types of nanovectors and their applications in various clinical situations, and finally, we spot the light on the future of this area of research.

Preparation, Drug Distribution, and In Vivo Evaluation of the Safety of Protein Corona Liposomes for Liraglutide Delivery

The development of oral drug delivery systems is challenging, and issues related to the mucus layer and low intestinal epithelial permeability have not yet been surmounted. The purpose of this study was to develop a promising formulation that is more adapted to in vivo absorption and to facilitate the administration of oral liraglutide. Cationic liposomes (CLs) linked to AT-1002 were prepared using a double-emulsion method, and BSA was adsorbed on the surface of the AT-CLs, resulting in protein corona cationic liposomes with AT-1002 (Pc-AT-CLs). The preparation method was determined by investigating various process parameters. The particle size, potential, and encapsulation efficiency (EE%) of the Pc-AT-CLs were 202.9 ± 12.4 nm, 1.76 ± 4.87 mV, and 84.63 ± 5.05%, respectively. The transmission electron microscopy (TEM) imaging revealed a nearly spherical structure of the Pc-AT-CLs, with a recognizable coating. The circular dichroism experiments confirmed that the complex preparation process did not affect the secondary structure of liraglutide. With the addition of BSA and AT-1002, the mucosal accumulation of the Pc-AT-CLs was nearly two times lower than that of the AT-CLs, and the degree of enteric metaplasia was 1.35 times higher than that of the PcCLs. The duration of the intestinal absorption of the Pc-AT-CLs was longer, offering remarkable biological safety.

A spotlight on application of microwave-assisted modifications of plant derived polymers in designing novel drug delivery systems

Polymers are a fundamental part of numerous industries and can be conjugated with many other materials and components to have a vast array of products. Biomaterials have been extensively studied for their application in pharmaceutical formulation development, tissue engineering, and biomedical areas. However, the native form of many polymers has limitations concerning microbial contamination, susceptibility, solubility, and stability. Chemical or physical modifications can overcome these limitations by tailoring the properties of polymers to meet several requirements. The polymer modifications are interdisciplinary, cutting across conventional materials, physics, biology, chemistry, medicine, and engineering limitations. Microwave irradiation has become a well-established technique for a few decades to drive and promote chemical modification reactions. This technique allows ease of temperature and power control to perform the synthesis protocols efficiently. Additionally, microwave irradiation contributes to green and sustainable chemistry. In this contribution, microwave-assisted polymer modifications were described with a special focus on their application in developing several novel dosage forms.

Biopolymeric nanocarrier: an auspicious system for oral delivery of insulin

Subcutaneous administration of insulin has been practiced for the clinical supervision of diabetes pathogenesis but it is often ineffective to imitate the glucose homeostasis and is always invasive. Therefore, it causes patient discomfort and infection of local tissue. These issues lead to finding an alternative route for insulin delivery that could be effective, promising, and non-invasive. However, delivery of insulin orally is the most suitable route but the rapid breakdown of insulin by the gastrointestinal enzymes becomes a major barrier to this method. Therefore, nanocarriers (which guard insulin against degradation and facilitate its uptake) are preferred for oral insulin delivery. Among various categories of nanocarriers, bio-polymeric nanocarriers draw special attention owing to their hydrophilic, non-toxic, and biodegradable nature. This review provides a detailed overview of insulin-loaded biopolymer-based nanocarriers, which give future direction in the optimization and development of a clinically functional formulation for their effective and safe delivery.

Construction of a double-responsive modified guar gum nanoparticles and its application in oral insulin administration

The use of intelligent insulin delivery systems has become more important for treating diabetes. In this study, a dual-responsive oral insulin delivery nanocarrier that responds to glucose and pH has been developed. First, the oleic acid hydrophobic modified guar gum (GG) was synthesized by the esterification reaction, and the γ-polyglutamic acid (γ-PGA) was coupled with GG by the amidation reaction. The obtained pH-responsive copolymer (γ-PGA-GG) was cross-linked by concanavalin A to obtain pH/glucose dual-responsive nanocarriers, and insulin was effectively loaded into the dual-responsive nanocarriers. The insulin-loaded nanoparticles can achieve effective pH and glucose responses, releasing insulin on demand. In vitro and in vivo studies demonstrated the dual-responsive nanoparticles can protect insulin against the pH changes in the digestive tract and deliver insulin into the body to exert a hypoglycemic effect. Moreover, the dual-responsive nanoparticles have significant potential to be employed for oral insulin delivery.

Improving Antibacterial Efficiency of Curcumin in Magnetic Polymeric Nanocomposites

In recent years, resistance to chemical antibiotics, as well as their side effects, has caused a necessity to utilize natural substances and herbal components with antibacterial effects. Curcumin, the major substance of Curcuma longa’s rhizome, was used as an antibacterial agent since ancient times. This work aimed to formulate a novel nanocomposite for the delivery of curcumin to overcome orthodox drugs resistance against bacteria and improve its efficacy. To fabricate targeting nanocomposites, first, Fe3O4 nanoparticles were synthesized followed by coating the obtained nanoparticles using sodium alginate containing curcumin. A 2 by 3 factorial design was tailored to predict the optimum formulation of nanocomposites. Characterization of nanocomposites including particle size, polydispersity index (PDI), zeta potential, entrapment efficiency, and drug loading was performed. The optimum formulation was analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier-transformed infrared spectroscopy (FT-IR), and in vitro release study at different pHs. Finally, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of samples against seven common bacteria were determined. Results showed that the optimized formulation contained 400 nm particles with the PDI and zeta potentials of 0.4 and − 58 mV, respectively. The optimized formulation with 70% entrapment efficiency reduced the MIC value 2 to 4 times in comparison with pure curcumin. Results also showed that polymer and drug concentrations can significantly affect entrapment efficiency. In conclusion, the current investigation demonstrated that this magnetic nanocomposite can be applied for the delivery of curcumin.

Graphical abstract

A review of the berberine natural polysaccharide nanostructures as potential anticancer and antibacterial agents

Despite the promising medicinal properties, berberine (BBR), due to its relatively poor solubility in plasma, low bio-stability and limited bioavailability is not used broadly in clinical stages. Due to these drawbacks, drug delivery systems (DDSs) based on nanoscale natural polysaccharides, are applied to address these concerns. Natural polymers are biodegradable, non-immunogenic, biocompatible, and non-toxic agents that are capable of trapping large amounts of hydrophobic compounds in relatively small volumes. The use of nanoscale natural polysaccharide improves the stability and pharmacokinetics of the small molecules and, consequently, increases the therapeutic effects and reduces the side effects of the small molecules. Therefore, this paper presents an overview of the different methods used for increasing the BBR solubility and bioavailability. Afterwards, the pharmacodynamic and pharmacokinetic of BBR nanostructures were discussed followed by the introduction of natural polysaccharides of plant (cyclodextrines, glucomannan), the shells of crustaceans (chitosan), and the cell wall of brown marine algae (alginate)-based origins used to improve the dissolution rate of poorly soluble BBR and their anticancer and antibacterial properties. Finally, the anticancer and antibacterial mechanisms of free BBR and BBR nanostructures were surveyed. In conclusion, this review may pave the way for providing some useful data in the development of BBR-based platforms for clinical applications.

A systematic review of functionalized polymeric nanoparticles to improve intestinal permeability of drugs and biological products

BACKGROUND

The oral route is the most frequently used and the most convenient route of drug administration, since it has several advantages, such as ease of use, patient compliance and better cost-effectiveness. However, physicochemical and biopharmaceutical limitations of various active pharmaceutical ingredients (API) hinder suitability for this route, including degradation in the gastrointestinal tract, low intestinal permeability and low bioavailability. To overcome these problems, while maintaining therapeutic efficacy, polymeric nanoparticles have attracted considerable attention for their ability to increase drug solubility, promote controlled release, and improve stability. In addition, the functionalization of nanocarriers can increase uptake and accumulation at the target site of action, and intestinal absorption, making it possible to obtain more viable, safe and efficient treatments for oral administration. <P> Objective: This systematic review aimed to seek recent advances in the literature on the use of polymeric nanoparticles functionalization to increase intestinal permeability of APIs that are intended for oral administration. <P> Method: Two bibliographic databases were consulted (PubMed and ScienceDirect). The selected publications and the writing of this systematic review were based on the guidelines mentioned in the PRISMA statement. <P> Results: Out of a total of 3036 studies, 22 studies were included in this article based on our eligibility criteria. The results were consistent for the application of nanoparticle functionalization to increase intestinal permeability. <P> Conclusion: The functionalized polymeric nanoparticles can be considered as carrier systems that improve the intestinal permeability and bioavailability of APIs, with the potential to result, in the future, in the development of oral medicines.

Mesenchymal Stem Cells, Bioactive Factors, and Scaffolds in Bone Repair: From Research Perspectives to Clinical Practice

Mesenchymal stem cell-based therapies are promising tools for bone tissue regeneration. However, tracking cells and maintaining them in the site of injury is difficult. A potential solution is to seed the cells onto a biocompatible scaffold. Construct development in bone tissue engineering is a complex step-by-step process with many variables to be optimized, such as stem cell source, osteogenic molecular factors, scaffold design, and an appropriate in vivo animal model. In this review, an MSC-based tissue engineering approach for bone repair is reported. Firstly, MSC role in bone formation and regeneration is detailed. Secondly, MSC-based bone tissue biomaterial design is analyzed from a research perspective. Finally, examples of animal preclinical and human clinical trials involving MSCs and scaffolds in bone repair are presented.

Formulation and Evaluation of Linum usitatissimum Mucilage-Based Nanoparticles for Effective Delivery of Ezetimibe

Introduction

The aim of current study was to prepare Linum usitatissimum mucilage (LUM) based nanoparticles, capable of encapsulating hydrophobic drug ezetimibe as nanocarriers.

Methods

Solvent evaporation and nanoprecipitation techniques were used to develop nanoparticles by encapsulating ezetimibe in the articulated matrix of polysaccharide fractions. Developed nanoparticles were characterized to determine the particle size, zeta potential, polydispersibility index (PDI), and entrapment efficiency (EE). Morphology and physicochemical characterization were carried out through SEM, FTIR, PXRD and thermal analysis. Saturation solubility and in vitro release studies were also performed. Safety assessment of ezetimibe loaded nanoparticles was evaluated via oral acute toxicity study.

Results

The mean particle size, zeta potential, PDI and EE for emulsion solvent evaporation were 683.6 nm, -28.3 mV, 0.39, 63.7% and for nanoprecipitation were 637.7 nm, 0.07, -27.1 mV and 80%, respectively. Thermal analysis confirmed enhanced thermal stability, whereas PXRD confirmed amorphous nature of drug. Saturation solubility (p-value <0.05) demonstrated improved solubility of drug when enclosed in linseed nanoparticles. Nanoprecipitation surpasses emulsion solvent evaporation in dissolution test by possessing smaller size. Acute oral toxicity study indicated no significant changes in behavioral, clinical or histopathological parameters of control and experimental groups.

Conclusion

The in vitro release of ezetimibe was augmented by enhancing aqueous solubility through devised nanoparticles. Thus, linseed mucilage could act as biopolymer in the fabrication of nanoparticle formulation. The acute oral toxicological investigations provided evidence that LUMNs were safe after oral administration.

Synthesis and In Vivo Evaluation of Insulin-Loaded Whey Beads as an Oral Peptide Delivery System

For many diabetics, daily, lifelong insulin injections are required to effectively manage blood glucose levels and the complications associated with the disease. This can be a burden and reduces patient quality of life. Our goal was to develop a more convenient oral delivery system that may be suitable for insulin and other peptides. Insulin was entrapped in 1.5-mm beads made from denatured whey protein isolate (dWPI) using gelation. Beads were then air-dried with fumed silica, Aerosil^®. The encapsulation efficiency was ~61% and the insulin loading was ~25 µg/mg. Dissolution in simulated gastric-, and simulated intestinal fluids (SGF, SIF) showed that ~50% of the insulin was released from beads in SGF, followed by an additional ~10% release in SIF. The omission of Aerosil^® allowed greater insulin release, suggesting that it formed a barrier on the bead surface. Circular dichroism analysis of bead-released insulin revealed an unaltered secondary structure, and insulin bioactivity was retained in HepG2 cells transfected to assess activation of the endogenous insulin receptors. Insulin-entrapped beads were found to provide partial protection against pancreatin for at least 60 min. A prototype bead construct was then synthesised using an encapsulator system and tested in vivo using a rat intestinal instillation bioassay. It was found that 50 IU/kg of entrapped insulin reduced plasma glucose levels by 55% in 60 min, similar to that induced by subcutaneously (s.c.)-administered insulin (1 IU/kg). The instilled insulin-entrapped beads produced a relative bioavailability of 2.2%. In conclusion, when optimised, dWPI-based beads may have potential as an oral peptide delivery system.

Oral Nano Drug Delivery Systems for the Treatment of Type 2 Diabetes Mellitus: An Available Administration Strategy for Antidiabetic Phytocompounds

In view of the worldwide serious health threat of type 2 diabetes mellitus (T2DM), natural sources of chemotherapies have been corroborated as the promising alternatives, with the excellent antidiabetic activities, bio-safety, and more cost-effective properties. However, their clinical application is somewhat limited, because of the poor solubility, instability in the gastrointestinal tract (GIT), low bioavailability, and so on. Nowadays, to develop nanoscaled systems has become a prominent strategy to improve the drug delivery of phytochemicals. In this review, we primarily summarized the intervention mechanisms of phytocompounds against T2DM and presented the recent advances in various nanosystems of antidiabetic phytocompounds. Selected nanosystems were grouped depending on their classification and structures, including polymeric NPs, lipid-based nanosystems, vesicular systems, inorganic nanocarriers, and so on. Based on this review, the state-of-the-art nanosystems for phytocompounds in T2DM treatment have been presented, suggesting the preponderance and potential of nanotechnologies.

Comparative study of photoinitiators for the synthesis and 3D printing of a light-curable, degradable polymer for custom-fit hard tissue implants

Three-dimensional (3D) printing enhances the production of on-demand fabrication of patient-specific devices, as well as anatomically fitting implants with high complexity in a cost-effective manner. Additive systems that employ vat photopolymerisation such as stereolithography (SLA) and digital light projection are used widely in the field of biomedical science and engineering. However, additive manufacturing methods can be limited by the types of materials that can be used. In this study, we present an isosorbide-based formulation for a polymer resin yielding a range of elastic moduli between 1.7 and 3 GN mm^-2 dependent on the photoinitiator system used as well as the amount of calcium phosphate filler added. The monomer was prepared and enhanced for 3D-printing using an SLA technique that delivered stable and optimized 3D-printed models. The resin discussed could potentially be used following major surgery for the correction of congenital defects, the removal of oral tumours and the reconstruction of the head and neck region. The surgeon is usually limited with devices available to restore both function and appearance and with the ever-increasing demand for low-priced and efficient facial implants, there is an urgent need to advance new manufacturing approaches and implants with a higher osseointegration performance.

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.

Effect of Artemisia absinthium ethanolic extract on oxidative stress markers and the TLR4, S100A4, Bax and Bcl-2 genes expression in the kidney of STZ-induced diabetic rats

OBJECTIVES

The present study was conducted to examine antidiabetic effects of Artemisia absinthium ethanolic extract [A. absinthium] and to investigate its effects on oxidative stress markers and the expression of TLR4, S100A4, Bax and Bcl-2 genes in the kidney of STZ-induced diabetic rats.

METHODS

Thirty six rats (weight 200-250 g) were randomly divided into diabetes and control groups. Induction of diabetes was performed using STZ (55 mg/kg.bw). Biochemical parameters and oxidative stress markers (SOD and MDA) were measured using spectrophotometry after 60 days of treatment. The expression of TLR4, S100A4, Bax and Bcl-2 were analyzed by real-time PCR. One-way analysis of variance (ANOVA) and Bonferroni post hoc test were used to compare the data.

RESULTS

Diabetes significantly impairs the serum fasting blood glucose (FBG), lipid profile, urea, creatinine and albumin. At the end of treatment with A. absinthium extract, these parameters were close to the normal range. The results showed that the A. absinthium extract significantly decreased the kidney expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress markers (SOD and MDA) in the kidney tissues of treated rats. Also, all of these beneficial effects of the A. absinthium were dose-dependent.

CONCLUSIONS

The extract of A. absinthium possesses antidiabetic effects. A. absinthium decreased the expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress. Therefore, this herbal extract can be used as an adjuvant treatment for diabetic complications.

Sterculia striata gum as a potential oral delivery system for protein drugs

Natural polysaccharides have been investigated as vehicles for oral insulin administration. Because of their non-toxic, renewable, low cost and readily available properties, gums find multiple applications in the pharmaceutical industry. This work aimed to develop a Sterculia striata gum-based formulation associated with additional biopolymers (dextran sulfate, chitosan, and albumin), a crosslinking agent (calcium chloride) and stabilizing agents (polyethylene glycol and poloxamer 188), to increase the oral bioavailability of proteins. Insulin was used as a model drug and the methods used to prepare the formulation were based on ionotropic pregelation followed by electrolytic complexation of oppositely charged biopolymers under controlled pH conditions. The developed formulation was characterized to validate its efficacy, by the determination of its average particle size (622 nm), the insulin encapsulation efficiency (70%), stability in storage for 30 days, and the in vitro mucoadhesion strength (92.46 mN). Additionally, the developed formulation preserved about 64% of initial insulin dose in a simulated gastric medium. This study proposed, for the first time, a Sterculia striata gum-based insulin delivery system with potential for the oral administration of protein drugs, being considered a valid alternative for efficient delivery of those drugs.

The effects of synthetic orally administrated insulin nanoparticles in comparison to injectable insulin on the renal function markers of type 1- diabetic rats

OBJECTIVES

Injectable insulin is the most widely used therapy in patients with type 1 diabetes which has several disadvantages. The present study was aimed to evaluate the efficacy of injectable insulin on diabetes mellitus-related complications in comparison to orally encapsulated insulin nanoparticles.

MATERIALS AND METHODS

This study involved 42 Wistar rats separated into 5 groups, including control (C), diabetic control (D), diabetic receiving regular insulin (INS), diabetic receiving encapsulated insulin nanoparticle (INP), and diabetic receiving chitosan for two months. Biochemical parameters in serum and urine were measured using spectrophotometric or ELISA methods. mRNA levels of kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were evaluated using quantitative PCR.

RESULTS

There were no significant differences between the two forms of insulin in controlling the glycemic condition (P-value>0.05), but oral INP was more effective in correcting diabetic dyslipidemia in comparison to injectable insulin (P-value<0.05). Urine volume and creatinine excretion were significantly modulated by insulin and oral INP in diabetic groups (P-value<0.05), although the effects of INP on the modulation of execration of urea, acid uric, and albumin was more dramatic. Oral INP caused a significant decrease in urine concentration of KIM-1 and NGAL as well as expression of KIM-1 in renal tissue (P-value<0.05).

CONCLUSION

Our results suggested that oral INP is more effective than injectable insulin in modulation of urine and serum diabetic-related parameters.

An Enteric-Coated Polyelectrolyte Nanocomplex Delivers Insulin in Rat Intestinal Instillations when Combined with a Permeation Enhancer

The use of nanocarriers is being researched to achieve oral peptide delivery. Insulin-associated anionic polyelectrolyte nanoparticle complexes (PECs) were formed that comprised hyaluronic acid and chitosan in an optimum mass mixing ratio of 5:1 (MR 5), followed by coating with a pH-dependent polymer. Free insulin was separated from PECs by size exclusion chromatography and then measured by HPLC. The association efficiency of insulin in PECs was >95% and the loading was ~83 µg/mg particles. Dynamic light scattering and nanoparticle tracking analysis of PECs revealed low polydispersity, a negative zeta potential range of −40 to −50 mV, and a diameter range of 95–200 nm. Dissolution studies in simulated small intestinal fluid (FaSSIF-V2) revealed that the PECs were colloidally stable. PECs that were coated with Eudragit^® L-100 delayed insulin release in FaSSIF-V2 and protected insulin against pancreatin attack more than uncoated PECs. Uncoated anionic PECs interacted weakly with mucin in vitro and were non-cytotoxic to Caco-2 cells. The coated and uncoated PECs, both concentrated further by ultrafiltration, permitted dosing of 50 IU/kg in rat jejunal instillations, but they failed to reduce plasma glucose or deliver insulin to the blood. When ad-mixed with the permeation enhancer (PE), sucrose laurate (100 mM), the physicochemical parameters of coated PECs were relatively unchanged, however blood glucose was reduced by 70%. In conclusion, the use of a PE allowed for the PEC-released bioactive insulin to permeate the jejunum. This has implications for the design of orally delivered particles that can release the payload when formulated with enhancers.

Polymeric Films for the Encapsulation, Storage, and Tunable Release of Therapeutic Microbes

Microbe-based therapeutics (MBTs) are an emerging therapeutic modality for treating gastrointestinal infections and inflammatory bowel diseases. Current formulations for oral delivery of MBTs use capsules to achieve safe gastric transit, but oral formulations that control the spatiotemporal concentration of MBTs are yet to be developed, despite well-established connections between all therapeutics and their location, concentration, and distribution at sites of action. The development of a multi-functional polymer-based encapsulation system to formulate MBTs for enhanced storage and delivery through formulation of a model MBT, Lactobacillus casei ATCC393, is reported here. This approach enables the additive inclusion of excipients and polymers to grant specific functions, toward the development of a modular MBT platform. Through addition of established excipients, the formulation provides long-term storage of the encapsulated MBT. By adding higher molecular weight polymers, the release kinetics of the encapsulated MBTs can be modified. The inclusion of a mucoadhesive polymer significantly increases the adhesion force between the formulation and the intestinal tissue. Together, mucoadhesive and sustained release properties can be used to modulate the spatiotemporal concentration of MBTs. The formulation is compatible with standard oral capsules, thus maintaining existing clinical advantages of oral capsules while providing new functions from film encapsulation.

Antidiabetic and protective effects of Scrophularia striata ethanolic extract on diabetic nephropathy via suppression of RAGE and S100A8 expression in kidney tissues of streptozotocin-induced diabetic rats

Background The present study was conducted to examine the antidiabetic effects of Scrophularia striata ethanolic extract and to evaluate its effects on oxidative stress markers and RAGE and S100A8 gene expressions in the kidney of type 1 diabetic rats. Methods A total of 36 rats (weight 200-250 g) were randomly assigned into six groups as follows: Cnt, Cnt + S. striata 100, and Cnt + S. striata 200 that received normal saline, 100 mg/kg bw, and 200 mg/kg bw of ethanol extract of S. striata, respectively; and group Dibt, Dibt + S. striata 100, and Dibt + S. striata 200 that received normal saline, 100 mg/kg bw, and 200 mg/kg bw of ethanol extract of S. striata, respectively. Type 1 diabetes was induced in rats by a single injection of streptozotocin (55 mg/kg bw). After 60 days of treatment, biochemical factors and oxidative stress markers (superoxide dismutase [SOD] and malondialdehyde [MDA]) were measured using spectrophotometric methods. RAGE and S100A8 gene expressions were analyzed using real-time polymerase chain reaction. Results Diabetes significantly impairs serum and urine fasting blood glucose (FBG), lipid profile, creatinine, urea, and albumin parameters. After the treatment with S. striata extract, these parameters are close to the normal range. It was shown that the S. striata extract significantly decreased the kidney expression levels of RAGE and S100A8 genes and improved oxidative stress markers (SOD and MDA) in the kidney tissues when compared with the diabetic control group. It was also found that the beneficial effects of the S. striata were dose dependent. Conclusions The ethanolic extract of S. striata has beneficial antidiabetic effects. Moreover, by reducing RAGE and S100A8 gene expressions and by improving oxidative stress, S. striata might be used as adjuvant treatment for diabetic complications.

Complex Polysaccharide-Based Nanocomposites for Oral Insulin Delivery

Polyelectrolyte nanocomposites rarely reach a stable state and aggregation often occurs. Here, we report the synthesis of nanocomposites for the oral delivery of insulin composed of alginate, dextran sulfate, poly-(ethylene glycol) 4000, poloxamer 188, chitosan, and bovine serum albumin. The nanocomposites were obtained by Ca²⁺-induced gelation of alginate followed by an electrostatic-interaction process among the polyelectrolytes. Chitosan seemed to be essential for the final size of the nanocomposites and there was an optimal content that led to the synthesis of nanocomposites of 400–600 nm hydrodynamic size. The enhanced stability of the synthesized nanocomposites was assessed with LUMiSizer after synthesis. Nanocomposite stability over time and under variations of ionic strength and pH were assessed with dynamic light scattering. The rounded shapes of nanocomposites were confirmed by scanning electron microscopy. After loading with insulin, analysis by HPLC revealed complete drug release under physiologically simulated conditions.

A Delivery System for Oral Administration of Proteins/Peptides Through Bile Acid Transport Channels

Proteins and peptides are poorly absorbed via oral administration because of the gastrointestinal tract environment and lysosomal digestion after apical endocytosis. A delivery system, consisting of a deoxycholic acid-conjugated nanometer-sized carrier, may enhance the absorption of proteins in the intestine via the bile acid pathway. Deoxycholic acid is first conjugated to chitosan. Liposomes are then prepared and loaded with the model drug insulin. Finally, the conjugates are bound to the liposome surface to form deoxycholic acid and chitosan conjugate-modified liposomes (DC-LIPs). This study demonstrates that DC-LIPs can promote the intestinal absorption of insulin via the apical sodium-dependent bile acid transporter, based on observing fluorescently stained tissue slices of the rat small intestine and a Caco-2 cell uptake experiment. Images of intestinal slices revealed that excellent absorption of DC-LIPs is achieved via apical sodium-dependent bile acid transporter, and a flow cytometry experiment proved that DC-LIPs are a highly efficient delivery carrier. Caco-2 cells were also used to study the lysosome escape ability of DC-LIPs. We learned from confocal microscopy photographs that DC-LIPs can protect their contents from being destroyed by the lysosome. Finally, according to pharmacokinetic analyses, insulin-loaded DC-LIPs show a significant hypoglycemic effect with an oral bioavailability of 16.1% in rats with type I diabetes.

Development of pH Sensitive Alginate/Gum Tragacanth Based Hydrogels for Oral Insulin Delivery

Insulin entrapped alginate-gum tragacanth (ALG-GT) hydrogels at different ALG replacement ratios (100, 75, 50, 25) were prepared through an ionotropic gelation method, followed by chitosan (CH) polyelectrolyte complexation. A mild gelation process without the use of harsh chemicals was proposed to improve insulin efficiency. Retention of almost the full amount of entrapped insulin in a simulated gastric environment and sustained insulin release in simulated intestinal buffer indicated the pH sensitivity of the gels. Insulin release from hydrogels with different formulations showed significant differences ( p < 0.05). Time domain (TD) NMR relaxometry experiments also showed the differences for different formulations, and the presence of CH revealed that ALG-GT gel formulation could be used as an oral insulin carrier at optimum concentrations. The hydrogels formulated from biodegradable, biocompatible, and nontoxic natural polymers were seen as promising devices for potential oral insulin delivery.

Nanoparticulate-based drug delivery systems for small molecule anti-diabetic drugs: An emerging paradigm for effective therapy

Emergence of nanoparticulate drug delivery systems in diabetes has facilitated improved delivery of small molecule drugs which could dramatically improve the quality of life for diabetics. Conventional dosage forms of the anti-diabetic drugs exhibit variable/less bioavailability and short half-life, demanding frequent dosing and causing increased side-effects resulting in ineffectiveness of therapy and non-compliance with the patients. Considering the chronic nature of diabetes, nanotechnology-based approaches are more promising in terms of providing site-specific delivery of drugs with higher bioavailability and reduced dosage regimen. Nanomedicines act at the cellular and molecular levels to enhance the uptake of the drug into the cells or block the efflux mechanisms thus retaining the drug inside the cell for a longer duration of time. Many studies have hinted at the possibility of administering peptide drugs like glucagon like peptides orally by encapsulation into nanoparticles. Nanoparticles also allow further modifications including their encapsulation into microparticles, polyethylene glycol (PEG)-PEGylation- or functionalization with ligands for active targeting. Nevertheless, such remarkable benefits are fraught with their long-term safety concerns, regulatory hurdles, limitations of scale-up and ineffective patent protection which have hindered their commercialization. This review summarizes the latest advances in the area of nanoformulations as applied to the delivery of anti-diabetics. STATEMENT OF SIGNIFICANCE: The present work describes the latest advancements in the area of nanoformulations for anti-diabetic therapy along with highlighting the advantages that these nanoformulations offer at molecular level for diabetes. Although several potent orally active anti-hyperglycemic agents are available, the current challenges in efficient management of diabetes include optimization of the present therapies to ensure an optimum and stable level of glucose, and also to reduce the occurrence of long term complications associated with diabetes. Nanoformulations because of their high surface area to volume ratio provide improved efficacy, targeting their delivery to the desired site of action tends to minimize adverse effects and administration of peptide drugs by oral route is also possible by encapsulating them in nanoparticles. As we reflect on the success and failures of latest research on nanoformulations for the treatment of diabetes, it is important not to dwell on lack of FDA approvals but rather define future directions that guarantee more effective anti-diabetic treatment. In proposed review we have explored the latest advancement in anti-diabetic nanotechnology based formulations.

Applying emerging technologies to improve diabetes treatment

Insulin, as the most important drug for the treatment of diabetes, can effectively control the blood glucose concentration in humans. Due to its instability, short half-life, easy denaturation and side effects, the administration way of insulin are limited to subcutaneous injection accompany with poor glucose control and low patient compliance. In recent years, emerging insulin delivery systems have been developed in diabetes research. In this review, a variety of stimuli-responsive insulin delivery systems with their response mechanism and regulation principle are described. Further, the introduction of stem cell transplantation and mobile application based delivery technologies are prudent for the diabetes treatment. This article also discusses the advantages and limitations of current strategies, along with the opportunities and challenges for future insulin therapy.

Oral Administration of Salecan-Based Hydrogels for Controlled Insulin Delivery

We present an improved type of food gum (salecan) based hydrogels for oral delivery of insulin. Structural hydrogel formation was assessed with Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. We found that the hydrogel modulus, morphology, and swelling properties can be controlled by varying the salecan dose during hydrogel formation. Insulin was introduced into the hydrogel using a swelling-diffusion approach and then further used a drug prototype. In vitro insulin release profiles demonstrated that the release of entrapped insulin was suppressed in acidic conditions but markedly increased at neutral pH. Cell viability and toxicity tests revealed that the salecan hydrogel constructs were biocompatible. Oral administration of insulin-loaded salecan hydrogels in diabetic rats resulted in a sustained decrease of fasting plasma glucose levels over 6 h postadministration. For nondiabetic animals, the relative pharmacological bioavailability of insulin was significantly larger (6.24%, p < 0.05) for insulin-loaded hydrogels compared to free insulin. These results encourage further development of salecan-based hydrogels as vehicles for controlled insulin delivery following oral administration.