Photocrosslinking of dextran and polyaspartamide derivatives: A combination suitable for colon-specific drug delivery

Microfluidic-based multifunctional microspheres for enhanced oral co-delivery of probiotics and postbiotics

Probiotic-based therapies have shown great potential in the prevention and treatment of many diseases by positively regulating intestinal flora homeostasis. However, the efficacy of oral probiotics is severely limited due to the loss of bioactivity, short intestinal retention time, and insufficient therapeutic effect. Here, based on droplet microfluidics, we developed a hydrogel microsphere with colonic targeting and mucoadhesive capabilities as a multifunctional delivery platform, which can be used for co-delivery of probiotics (Escherichia coli Nissle 1917, EcN) and auxiliary molecules (indole-3-propionic acid, IPA), achieving synergistic therapeutic effects. In vivo studies shown that the integrated multifunctional microspheres can significantly reduce intestinal inflammation, repair intestinal barrier function, enhance probiotic colonization in the intestine, and modulate disordered intestinal flora, demonstrating enhanced therapeutic effects in a mouse model of colitis. This work reveals that microfluidic-based smart droplet microspheres can provide a versatile platform for advanced microbial therapies.

Past, present and future of biomedical applications of dextran-based hydrogels: A review

This review extensively surveys the biomedical applications of hydrogels containing dextran. Dextran has gained much attention as a biomaterial due to its distinctive properties such as biocompatibility, non-toxicity, water solubility and biodegradability. It has emerged as a critical constituent of hydrogels for biomedical applications including drug delivery devices, tissue engineering scaffolds and biosensor materials. The benefits, challenges and potential prospects of dextran-based hydrogels as biomaterials are highlighted in this review.

Multifunctional hydrogels based on chitosan, hyaluronic acid and other biological macromolecules for the treatment of inflammatory bowel disease: A review

Hydrogel is a three-dimensional network polymer material rich in water. It is widely used in the biomedical field because of its unique physical and chemical properties and good biocompatibility. In recent years, the incidence of inflammatory bowel disease (IBD) has gradually increased, and the disadvantages caused by traditional drug treatment of IBD have emerged. Therefore, there is an urgent need for new treatments to alleviate IBD. Hydrogel has become a potential therapeutic platform. However, there is a lack of comprehensive review of functional hydrogels for IBD treatment. This paper first summarizes the pathological changes in IBD sites. Then, the action mechanisms of hydrogels prepared from chitosan, sodium alginate, hyaluronic acid, functionalized polyethylene glycol, cellulose, pectin, and γ-polyglutamic acid on IBD were described from aspects of drug delivery, peptide and protein delivery, biologic therapies, loading probiotics, etc. In addition, the advanced functions of IBD treatment hydrogels were summarized, with emphasis on adhesion, synergistic therapy, pH sensitivity, particle size, and temperature sensitivity. Finally, the future development direction of IBD treatment hydrogels has been prospected.

Advanced bioactive nanomaterials for diagnosis and treatment of major chronic diseases

With the rapid innovation of nanoscience and technology, nanomaterials have also been deeply applied in the medical and health industry and become one of the innovative methods to treat many diseases. In recent years, bioactive nanomaterials have attracted extensive attention and have made some progress in the treatment of some major chronic diseases, such as nervous system diseases and various malignant tumors. Bioactive nanomaterials depend on their physical and chemical properties (crystal structure, surface charge, surface functional groups, morphology, and size, etc.) and direct produce biological activity and play to the role of the treatment of diseases, compared with the traditional nanometer pharmaceutical preparations, biological active nano materials don't exert effects through drug release, way more directly, also is expected to be more effective for the treatment of diseases. However, further studies are needed in the evaluation of biological effects, fate in vivo, structure-activity relationship and clinical transformation of bionanomaterials. Based on the latest research reports, this paper reviews the application of bioactive nanomaterials in the diagnosis and treatment of major chronic diseases and analyzes the technical challenges and key scientific issues faced by bioactive nanomaterials in the diagnosis and treatment of diseases, to provide suggestions for the future development of this field.

Carbohydrate Polymer-Based Targeted Pharmaceutical Formulations for Colorectal Cancer: Systematic Review of the Literature

Colon cancer is the third most diagnosed cancer worldwide, followed by lung and breast cancer. Conventional treatment methods are associated with numerous side effects and compliance issues. Thus, colon targeted drug delivery has gained much attention due to its evident advantages. Although many technologies have been explored, the use of pH-sensitive polymers, especially biodegradable polymers, holds exceptional promise. This review aims to collate research articles concerning recent advances in this area. A systematic search using multiple databases (Google Scholar, EMBASE, PubMed, MEDLINE and Scopus) was carried out following the preferred reported items for systematic reviews and meta-analyses (PRISMA) guidelines with an aim to explore the use of pH-sensitive carbohydrate polymers in developing colon targeted pharmaceutical formulations. Following screening and quality assessment for eligibility, 42 studies were included, exploring either single or a combination of carbohydrate polymers to develop targeted formulations for colon cancer therapy. Pectin (11) is the most widely used of these biopolymers, followed by chitosan (09), alginate (09) and guar gum (08). This systematic review has successfully gathered experimental evidence highlighting the importance of employing carbohydrate polymers in developing targeting formulations to manage colon cancer.

Synthesis, characterization, and cytotoxicity evaluation of dextran-myristoyl-ECGKRK peptide conjugate

CGKRK is a well-known tumor homing peptide with significant specificity for many types of cancer tissues. Herein, we describe the synthesis of a novel drug delivery system based on dextran decorated with myristoyl-ECGKRK peptide. The myristoylated peptide was synthesized and conjugated to dextran via an ester bond followed by purification. FT-IR and NMR confirmed the success of the conjugation reaction, while the surface morphology examination revealed that the conjugate has a characteristic porous network-like structure. Dynamic-light scattering measurements indicated the ability of the conjugate to self-assemble into nanoparticles with an average size of 248 ± 6.33 nm, and zeta potential of 10.7 mV. The cytotoxicity profiles for the peptide, dextran (Dex0), and dextran-peptide conjugate (Dex1) were evaluated against triple-negative breast cancer cells (MDA-MB-231), breast cancer cells (MCF-7), and human embryonic normal kidney cells (HEK-293). The results revealed that myristoyl-ECGKRK was noncytotoxic on the two different breast cancer cell lines up to 50 μM, but the cell viability was minimally reduced to 85% at 50 μm in HEK-293 cells. Similarly, Dex0 showed a neglected cytotoxicity profile at all tested concentrations. The Dex1 was not toxic to the cells up to a concentration of 8.3 mg/mL.

The dextrans as vehicles for gene and drug delivery

Dextran has become a hot research topic in drug vehicle material because of its biodegradable, nonspecific cell adhesion, resistance to protein adsorption, low price and ease of structural modification. The fate and changes of dextran in vivo are not fully understood. It is helpful to guide the design and modification of dextran drug vehicles to clarify the changes in the morphology, metabolism and function of drug targets. With the deep understanding of dextran and the emergence of new functional dextran derivatives, its application in nanodrug delivery systems will be more and more, clinically applicable delivery systems may also be available.

Inulin as a multifaceted (active) substance and its chemical functionalization: From plant extraction to applications in pharmacy, cosmetics and food

This review is aimed at critically discussing a collection of research papers on Inulin (INU) in different scientific fields. The first part of this work gives an overview on the main characteristics of native INU, including production, applications in food or cosmetics industries, its benefits on human health as well as its main nutraceutical properties. A particular focus is dedicated to the extraction techniques and to the specific effects of INU on intestinal microbiota. Other than in food industry, the number of INU applications increases dramatically in the pharmaceutical field especially due to its simple chemical functionalization. Thus, aim of this review is also to give practical examples of chemical functionalization performed on INU also by including critical comments based on the direct experience of the Authors. With this aim, a full paragraph is dedicated to practical chemical experiences useful to reduce the efforts when establishing new experimental conditions. Moreover, the pharmaceutical technology is also taken in special consideration by underlining the aspects leading at the preparation of formulations based on INU. At the end of the review, a critical paragraph is intended to feed the scientists' curiosity on this versatile polysaccharide.

A Micellar-Hydrogel Nanogrid from a UV Crosslinked Inulin Derivative for the Simultaneous Delivery of Hydrophobic and Hydrophilic Drugs

Hydrogels are among the most common materials used in drug delivery, as polymeric micelles are too. They, preferentially, load hydrophilic and hydrophobic drugs, respectively. In this paper, we thought to combine the favorable behaviors of both hydrogels and polymeric micelles with the specific aim of delivering hydrophilic and hydrophobic drugs for dual delivery in combination therapy, in particular for colon drug delivery. Thus, we developed a hydrogel by UV crosslinking of a methacrylated (MA) amphiphilic derivative from inulin (INU) (as known INU is specifically degraded into the colon) and vitamin E (VITE), called INVITEMA. The methacrylated micelles were physicochemically characterized and subjected to UV irradiation to form what we called the "nanogrids". The INVITEMA nanogrids were characterized by DSC, SEM, TEM, water uptake and beclomethasone dipropionate (BDP) release. In particular, the release of the hydrophobic drug was specifically assessed to verify that it can spread along the hydrophilic portions and, therefore, effectively released. These systems can open new pharmaceutical applications for known hydrogels or micelle systems, considering that in literature only few examples are present.

A novel dissolution media for testing drug release from a nanostructured polysaccharide-based colon specific drug delivery system: an approach to alternative colon media

The aim of this study was to develop a novel microbially triggered and animal-sparing dissolution method for testing of nanorough polysaccharide-based micron granules for colonic drug delivery. In this method, probiotic cultures of bacteria present in the colonic region were prepared and added to the dissolution media and compared with the performance of conventional dissolution methodologies (such as media with rat cecal and human fecal media). In this study, the predominant species (such as Bacteroides, Bifidobacterium, Lactobacillus species, Eubacterium and Streptococcus) were cultured in 12% w/v skimmed milk powder and 5% w/v grade “A” honey. Approximately 10¹⁰–10¹¹ colony forming units m/L of probiotic culture was added to the dissolution media to test the drug release of polysaccharide-based formulations. A USP dissolution apparatus I/II using a gradient pH dissolution method was used to evaluate drug release from formulations meant for colonic drug delivery. Drug release of guar gum/Eudragit FS30D coated 5-fluorouracil granules was assessed under gastric and small intestine conditions within a simulated colonic environment involving fermentation testing with the probiotic culture. The results with the probiotic system were comparable to those obtained from the rat cecal and human fecal-based fermentation model, thereby suggesting that a probiotic dissolution method can be successfully applied for drug release testing of any polysaccharide-based oral formulation meant for colonic delivery. As such, this study significantly adds to the nanostructured biomaterials’ community by elucidating an easier assay for colonic drug delivery.

Photo-irradiation paradigm: Mapping a remarkable facile technique used for advanced drug, gene and cell delivery

Undoubtedly, the progression of photo-irradiation technique has provided a smart engineering tool for the state-of-the-art biomaterials that guide the biomedical and therapeutic domains for promoting the modern pharmaceutical industry. Many investigators had exploited such a potential technique to create/ameliorate numerous pharmaceutical carriers. These carriers show promising applications that vary from small drug to therapeutic protein delivery and from gene to living cell encapsulation design. Harmony between the properties of precisely engineered precursors and the formed network structure broadens the investigator's intellect for both brilliant creations and effective applications. As well, controlling photo-curing at the formulation level, through manipulating the absorption of light stimuli, photoinitiator system and photo-responsive precursor, facilitates the exploration of novel distinctive biomaterials. Discussion of utilizing different photo-curing procedures in designing/formulation of different pharmaceutical carriers is the main emphasis of this review. In addition, recent applications of these intelligent techniques in targeted, controlled, and sustained drug delivery with understanding of photo-irradiation concept and mechanism are illustrated.

Injectable in situ forming hydrogels based on natural and synthetic polymers for potential application in cartilage repair

Injectable hydrogels based on hyaluronic acid, elastin and a biocompatible polyaspartamide are optimal scaffolds of viable chondrocytes for potential cartilage repair.

Novel osteoinductive photo-cross-linkable chitosan-lactide-fibrinogen hydrogels enhance bone regeneration in critical size segmental bone defects

The purpose of this study was to develop and characterize a novel photo-cross-linkable chitosan-lactide-fibrinogen (CLF) hydrogel and evaluate the efficacy of bone morphogenetic protein-2 (BMP-2) containing a CLF hydrogel for osteogenesis in vitro and in vivo. We synthesized the CLF hydrogels and characterized their chemical structure, degradation rate, compressive modulus and in vitro BMP-2 release kinetics. We evaluated bioactivities of the BMP-2 containing CLF hydrogels (0, 50, 100 and 500ngml(-1)) in vitro using W-20-17 preosteoblast mouse bone marrow stromal cells and C2C12 mouse myoblast cells. The effect of BMP-2 containing CLF gels (0, 0.5, 1, 2 and 5μg) on bone formation was evaluated using rat critical size segmental bone defects for 4weeks. Fourier transform infrared spectroscopy spectra and scanning electron microscopy images showed chemical and structural changes by the addition of fibrinogen into the chitosan-lactide copolymer. The incorporation of fibrinogen molecules significantly increased the compressive modulus of the hydrogels. The in vitro BMP-2 release study showed initial burst releases from the CLF hydrogels followed by sustained releases, regardless of the concentration of the BMP-2 over 4weeks. Cells in all groups were viable in the presence of the hydrogels regardless of BMP-2 doses, indicating non-cytotoxicity of hydrogels. Alkaline phosphate activity and mineralization of cells exhibited dose dependence on BMP-2 containing CLF hydrogels. Radiography, microcomputed tomography and histology confirmed that the BMP-2 containing CLF hydrogels prompted neo-osteogenesis and accelerated healing of the defects in a dose-dependent manner. Thus the CLF hydrogel is a promising delivery system of growth factors for bone regeneration.

Effects in cigarette smoke stimulated bronchial epithelial cells of a corticosteroid entrapped into nanostructured lipid carriers

BACKGROUND

Nanomedicine studies have showed a great potential for drug delivery into the lung. In this manuscript nanostructured lipid carriers (NLC) containing Fluticasone propionate (FP) were prepared and their biocompatibility and effects in a human bronchial epithelial cell line (16-HBE) stimulated with cigarette smoke extracts (CSE) were tested.

RESULTS

Biocompatibility studies showed that the NLC did not induce cell necrosis or apoptosis. Moreover, it was confirmed that CSE increased intracellular ROS production and TLR4 expression in bronchial epithelial cells and that FP-loaded NLC were more effective than free drug in modulating these processes. Finally, the nanoparticles increased GSH levels improving cell protection against oxidative stress.

CONCLUSIONS

The present study shows that NLC may be considered a promising strategy to improve corticosteroid mediated effects in cellular models associated to corticosteroid resistance. The NLC containing FP can be considered good systems for dosage forms useful for increasing the effectiveness of fluticasone decreasing its side effects.

In-situ forming gel-like depot of a polyaspartamide-polylactide copolymer for once a week administration of sulpiride

Objectives

An in-situ forming gel-like depot, prepared by using an appropriate polyaspartamide-polylactide graft copolymer, has been employed to release in a sustained way sulpiride.

Methods

α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-g-polylactic acid (PHEA-g-PLA) has been used as a polymer component. Its physicochemical properties make possible to dissolve it in N-methyl-2-pyrrolidone, with the obtainment of a solution able to form a gel-like depot once injected into a physiological medium. Cell compatibility of PHEA-g-PLA depot has been investigated, using murine dermal fibroblasts as cell model. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay and fluorescence microscopy have been employed to evaluate cell viability and morphology after contact with PHEA-g-PLA depot. Pharmacokinetic parameters of sulpiride released from depot have been determined following subcutaneous administration to rabbits and compared with corresponding parameters following administration of free sulpiride solution.

Key findings

It has been demonstrated that the system does not affect significantly the viability of fibroblasts and is able to sustain the release of sulpiride until a week, with a burst effect dependent on the initial weight ratio polymer/drug.

Conclusion

In-vivo release profiles and pharmacokinetic parameters suggest that PHEA-g-PLA depot could have interesting clinical applications for a once a week administration of poorly soluble drugs to humans or animals.

Preparation and characterisation of Dextran-70 hydrogel for controlled release of praziquantel

A hydrogel was developed from 70 kDa dextran (DEX-70) and praziquantel (PZQ) incorporated as a model drug. Biopharmaceutical properties, such as solubility and dissolution rate, were analysed in the design of the hydrogel. Furthermore, the hydrogel was also characterized by IR spectroscopy and DSC. Tests of the swelling rate showed that the hydrogel swelled slowly, albeit faster than the rate for the free polymer. In dissolution tests, the hydrogel released the drug slowly and continuously. This slow release was similar to that observed in the swelling tests and resulted in controlled release of the drug. Thus, this dextran is a suitable polymer for the development of hydrogels as vehicles for the controlled release of drugs.

Development of pH- and enzyme-controlled, colon-targeted, pulsed delivery system of a poorly water-soluble drug: preparation and in vitro evaluation

BACKGROUND

As conventional pH-controlled colon-targeted system used for oral drug delivery often shows a poor performance, a more effective way to preserve poorly water-soluble drug from releasing in upper gastrointestinal tract should be researched.

METHOD

The objective of this study was to develop a novel colon-targeted drug delivery system using guar gum and Eudragit as enzyme- and pH-based materials. Lansoprazole, a poorly water-soluble drug was used as model drug. Under three different conditions, the in vitro drug release behaviors of this newly developed system was evaluated, using β-mannanase, rat cecal content, and human fecal media to simulate the pH and enzyme during intestinal transit to the colon.

RESULTS

The released amount of lansoprazole in simulated small intestine fluid (pH 6.8) after 5 hours was less than 10% from the pH- and enzyme-controlled tablets compared with 80.01±0.3% in rat cecal content medium (pH 7.4).The degradation ability of human fecal slurries on PECCT-PT was independent of human age and gender. β-Mannanase did not have a similar effect on the degradation of polysaccharide as rat cecal enzymes and human fecal enzymes in our study. Scanning electron microscope study indicated that the dissolution mechanism of PECCT-PT should be corrosion.

CONCLUSION

The above results indicated this system could be served as a potential carrier to deliver poorly water-soluble drug specifically to the colon.

Affinity-based growth factor delivery using biodegradable, photocrosslinked heparin-alginate hydrogels

Photocrosslinkable biomaterials are promising for tissue engineering applications due to their capacity to be injected and form hydrogels in situ in a minimally invasive manner. Our group recently reported on the development of photocrosslinked alginate hydrogels with controlled biodegradation rates, mechanical properties, and cell adhesive properties. In this study, we present an affinity-based growth factor delivery system by incorporating heparin into photocrosslinkable alginate hydrogels (HP-ALG), which allows for controlled, prolonged release of therapeutic proteins. Heparin modification had minimal effect on the biodegradation profiles, swelling ratios, and elastic moduli of the hydrogels in media. The release profiles of growth factors from this affinity-based platform were sustained for 3weeks with no initial burst release, and the released growth factors retained their biological activity. Implantation of bone morphogenetic protein-2 (BMP-2)-loaded photocrosslinked alginate hydrogels induced moderate bone formation around the implant periphery. Importantly, BMP-2-loaded photocrosslinked HP-ALG hydrogels induced significantly more osteogenesis than BMP-2-loaded photocrosslinked unmodified alginate hydrogels, with 1.9-fold greater peripheral bone formation and 1.3-fold greater calcium content in the BMP-2-loaded photocrosslinked HP-ALG hydrogels compared to the BMP-2-loaded photocrosslinked unmodified alginate hydrogels after 8weeks implantation. This sustained and controllable growth factor delivery system, with independently controllable physical and cell adhesive properties, may provide a powerful modality for a variety of therapeutic applications.

Preparation and characterization of an injectable composite

Hydrogels are increasingly used in medicine due to their potential to be delivered into the body in a minimally invasive manner and to be gelated at the site of introduction subsequently. The aim of this study was to develop a novel injectable and in situ-forming gel composite (GC) comprised of calcium alginate hydrogel and nano-hydroxyapatite/collagen (nHAC), assess its rheological, mechanical and in vitro degradable properties, and discuss the gelation mechanism. Injectable property test showed that the injectability of GC was tunable. Rheological results indicated that three phases of pre-gel, sol-gel phase transformation and post-gel could be found in the process of gelation. The compressive elastic modulus (E) and shear modulus (G) are in the range of 17.0-56.0 kPa and 24.7-55.0 kPa, respectively. During the in vitro degradation, the wet weight increased in the first week, then declined in the following 3 weeks, but the dry weight lost continuously during whole study. Meanwhile, the surface changed greatly after 2 weeks, but samples did not break down up to 28 days. These data indicate that GC exhibits controllable initial setting time and final setting time, tunable injectability, which provides a possible injectable material for bone repair and bone tissue engineering.

Biocompatible polymeric micelles with polysorbate 80 for use in brain targeting

In this paper, the synthesis and characterization of novel amphiphilic graft copolymers based on an α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) backbone and D,L-polylactic acid (PLA) hydrophobic side chains are reported. These copolymers were obtained starting from PHEA-ethylenediamine (PHEA-EDA), which was functionalized with polysorbate 80 (PS(80)) and/or PLA in order to obtain the PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA samples, respectively. The degrees of derivatization, DD(PS80) and DD(PLA), of PHEA-EDA-PS(80)-PLA, calculated by (1)H-NMR, resulted in being 1.2 ± 0.03 mol% and 0.54 ± 0.05 mol%, respectively, while that of PHEA-EDA-PLA was found to be 0.60 ± 0.05 mol%. Size exclusion chromatography (SEC) analysis confirmed the occurrence of derivatization, the molecular weight values being close to the theoretical ones. Polymeric micelles from PHEA-EDA-PLA and PHEA-EDA-PS(80)-PLA copolymers were obtained by using the dialysis method and were characterized in terms of mean size, zeta potential, critical aggregation concentration (CAC), and surface composition by x-ray photoelectron spectroscopy (XPS) analysis, which demonstrated the presence of PS(80) onto the PHEA-EDA-PS(80)-PLA micelle surface. In vitro experiments demonstrated that these systems had no cytotoxic effects on 16 HBE, Caco2, HuDe and K562 cell lines, and no haemolytic activity. Moreover, both PHEA-EDA-PS(80)-PLA and PHEA-EDA-PLA micelles were able to penetrate into Neuro2a cells and, in the case of PS(80) decorated micelles, to escape from phagocytosis by the J774 A1 macrophages.