Evaluation of alginate-chitosan bioadhesive beads as a drug delivery system for the controlled release of theophylline

Polysaccharides as a Hydrophilic Building Block of Amphiphilic Block Copolymers for the Conception of Nanocarriers

Polysaccharides are gaining increasing attention for their relevance in the production of sustainable materials. In the domain of biomaterials, polysaccharides play an important role as hydrophilic components in the design of amphiphilic block copolymers for the development of drug delivery systems, in particular nanocarriers due to their outstanding biocompatibility, biodegradability, and structural versatility. The presence of a reducing end in polysaccharide chains allows for the synthesis of polysaccharide-based block copolymers. Compared with polysaccharide-based graft copolymers, the structure of block copolymers can be more precisely controlled. In this review, the synthesis methods of polysaccharide-based amphiphilic block copolymers are discussed in detail, taking into consideration the structural characteristics of polysaccharides. Various synthetic approaches, including reductive amination, oxime ligation, and other chain-end modification reactions, are explored. This review also focuses on the advantages of polysaccharides as hydrophilic blocks in polymeric nanocarriers. The structure and unique properties of different polysaccharides such as cellulose, hyaluronic acid, chitosan, alginate, and dextran are described along with examples of their applications as hydrophilic segments in the synthesis of amphiphilic copolymers to construct nanocarriers for sustained drug delivery.

Chitosan based hybrid superabsorbent for controlled drug delivery application

In the present study, a hybrid chitosan-alginate superabsorbent is prepared using maleic acid as a cross-linker and acrylamide as a grafting agent using the free radical mechanism. The composite hydrogel shows good swelling capacity along with hemocompatibility and biocompatibility and hence it is utilized as a drug delivery device. The characterization techniques including x-ray diffraction, Fourier transform infrared, x-ray photoelectron spectroscopy, and thermal analysis indicate the successful synthesis of stable hydrogel with rich functionalities. Metformin hydrochloride is used as a model drug which is used to treat diabetes. The drug encapsulation is done using the swelling diffusion method after the synthesis of hydrogel. The release of metformin from the drug-loaded hydrogel at physiological pH highlights the role of non-covalent interactions between the drug and hydrogel. In vitro release studies of Metformin from the drug-loaded hydrogel show higher release profiles at intestinal pH (7.4) compared to stomach pH (1.2). The observed cumulative release is 82.71% at pH 7.4 and 45.67% at pH 1.2 after 10 h. Brunauer-Emmett-Teller analysis reveals the effect of surface area, pore size, and pore volume of hydrogel on the drug release. The drug release from the hybrid chitosan-alginate hydrogel is found to be more sustained in comparison to the pure chitosan hydrogel. For the present drug delivery system, the swelling-controlled release is found to be more dominating than the pH-controlled release. The synthesized hydrogel can be successfully employed as a potential drug delivery system for controlled drug delivery.

Towards multifunctional robotic pills

Robotic pills leverage the advantages of oral pharmaceutical formulations-in particular, convenient encapsulation, high loading capacity, ease of manufacturing and high patient compliance-as well as the multifunctionality, increasing miniaturization and sophistication of microrobotic systems. In this Perspective, we provide an overview of major innovations in the development of robotic pills-specifically, oral pills embedded with robotic capabilities based on microneedles, microinjectors, microstirrers or microrockets-summarize current progress and applicational gaps of the technology, and discuss its prospects. We argue that the integration of multiple microrobotic functions within oral delivery systems alongside accurate control of the release characteristics of their payload provides a basis for realizing sophisticated multifunctional robotic pills that operate as closed-loop systems.

Recent developments in natural biopolymer based drug delivery systems

Targeted delivery of drug molecules to diseased sites is a great challenge in pharmaceutical and biomedical sciences. Fabrication of drug delivery systems (DDS) to target and/or diagnose sick cells is an effective means to achieve good therapeutic results along with a minimal toxicological impact on healthy cells. Biopolymers are becoming an important class of materials owing to their biodegradability, good compatibility, non-toxicity, non-immunogenicity, and long blood circulation time and high drug loading ratio for both macros as well as micro-sized drug molecules. This review summarizes the recent trends in biopolymer-based DDS, forecasting their broad future clinical applications. Cellulose chitosan, starch, silk fibroins, collagen, albumin, gelatin, alginate, agar, proteins and peptides have shown potential applications in DDS. A range of synthetic techniques have been reported to design the DDS and are discussed in the current study which is being successfully employed in ocular, dental, transdermal and intranasal delivery systems. Different formulations of DDS are also overviewed in this review article along with synthesis techniques employed for designing the DDS. The possibility of these biopolymer applications points to a new route for creating unique DDS with enhanced therapeutic qualities for scaling up creative formulations up to the clinical level.

Characterization and drug delivery characters of nanocomposite hydrogels based on gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG)/silver NPs

Nanocomposite hydrogels were prepared by gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG) in the presence of silver nanoparticles (Ag NPs). The effect of irradiation dose and Ag NPs content on the gel content and swelling characters of PVP/AG/Ag NPs copolymers was investigated. In addition, the structure-property behavior of the copolymers was characterized by IR spectroscopy, thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The drug uptake-release characters of PVP/AG/silver NPs copolymers, taking Prednisolone as a model drug, were studied. The study showed that the appropriate dose of gamma irradiation to achieve homogeneous nanocomposites hydrogel films and the highest swelling in water was 30 kGy, regardless of composition. The introduction of Ag NPs up to 5 wt % improved the physical properties and enhanced the drug uptake-release characters.

Chitosan-based blends for biomedical applications

Polysaccharides are the most abundant naturally available carbohydrate polymers; composed of monosaccharide units covalently connected together. Chitosan is the most widely used polysaccharides because of its exceptional biocompatibility, mucoadhesion, and chemical versatility. However, it suffers from a few drawbacks, e.g. poor mechanical properties and antibacterial activity for biomedical applications. Blending chitosan with natural or synthetic polymers may not merely improve its physicochemical and mechanical properties, but may also improve its bioactivity-induced properties. This review paper summarizes progress in chitosan blends with biodegradable polymers and polysaccharides and their biomedical applications. Blends of chitosan with alginate, starch, cellulose, pectin and dextran and their applications were particularly addressed. The critical and challenging aspects as well as the future ahead of the use of chitosan-based blends were eventually enlightened.

Oral Nanoparticles of SNX10-shRNA Plasmids Ameliorate Mouse Colitis

Background

Our previous study found that deletion of Sorting nexin 10 (SNX10) can protect against colonic inflammation and pathological damage induced by dextran sulfate sodium (DSS). This inspired us that modulation of SNX10 expression in colonic epithelial cells might represent a promising therapeutic strategy for inflammatory bowel disease (IBD).

Methods

Effective delivery of siRNA/shRNA to silence genes is a highly sought-after means in the treatment of multiple diseases. Here, we encapsulated SNX10-shRNA plasmids (SRP) with polylactide-polyglycolide (PLGA) to make oral nanoparticles (NPs), and then applied them to acute and chronic IBD mice model, respectively. The characteristics of the nanoparticles were assayed and the effects of SRP-NPs on mouse IBD were evaluated.

Results

High-efficiency SNX10-shRNA plasmids were successfully constructed and coated with PLGA to obtain nanoparticles, with a particle size of 275.2 ± 11.4mm, uniform PDI distribution, entrapment efficiency of 87.6 ± 2.5%, and drug loading of 13.11 ± 1.38%, displayed dominant efficiency of SNX10 RNA interference in the colon. In both acute and chronic IBD models, SRP-NPs could effectively reduce the loss of mice body weight, relieve the intestinal mucosal damage and inflammatory infiltration, inhibit the expression of inflammatory cytokines IL-1β, IL-23, TNF-α, and down-regulate the expression of toll-like receptors (TLRs) 2 and 4.

Conclusion

Oral nanoparticles of SNX10-shRNA plasmid displayed dominant efficiency of SNX10 RNA interference in the colon and ameliorate mouse colitis via TLR signaling pathway. SNX10 is a new target for IBD treatment and nanoparticles of SNX10-shRNA plasmid might be a promising treatment option for IBD.

Review of polysaccharide particle-based functional drug delivery

This review investigates the significant role polysaccharide particles play in functional drug delivery. The importance of these systems is due to the wide variety of polysaccharides and their natural source meaning that they can provide biocompatible and biodegradable systems with a range of both biological and chemical functionality valuable for drug delivery. This functionality includes protection and presentation of working therapeutics through avoidance of the reticuloendothelial system, stabilization of biomacromolecules and increasing the bioavailability of incorporated small molecule drugs. Transport of the therapeutic is also key to the utility of polysaccharide particles, moving drugs from the site of administration through mucosal binding and transport and using chemistry, size and receptor mediated drug targeting to specific tissues. This review also scrutinizes the methods of synthesizing and constructing functional polysaccharide particle drug delivery systems that maintain and extend the functionality of the natural polysaccharides.

A Polymer Chemistry Point of View on Mucoadhesion and Mucopenetration

Although oral is the preferred route of administration of pharmaceutical formulations, the long-standing challenge for medically active compounds to efficiently cross the mucus layer barrier limits its wider applicability. Efforts in nanomedicine to overcome this hurdle consider mucoadhesive and mucopenetrating drug carriers by selectively designing (macromolecular) building blocks. This review highlights and critically discusses recent strategies developed in this context including poly(ethylene glycol)-based modifications, cationic and thiolated polymers, as well as particles with high charge density, zeta-potential shifting ability, or mucolytic properties. The latest advances in ex vivo test platforms are also reviewed.

Preparation and Evaluation of Mucoadhesive Beads/Discs of Alginate and Algino-Pectinate of Piroxicam for Colon-Specific Drug Delivery Via Oral Route

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Chitosan electrodeposition for microrobotic drug delivery

A method to functionalize steerable magnetic microdevices through the co-electrodeposition of drug loaded chitosan hydrogels is presented. The characteristics of the polymer matrix have been investigated in terms of fabrication, morphology, drug release and response to different environmental conditions. Modifications of the matrix behavior could be achieved by simple chemical post processing. The system is able to load and deliver 40-80 μg cm(-2) of a model drug (Brilliant Green) in a sustained manner with different profiles. Chitosan allows a pH responsive behavior with faster and more efficient release under slightly acidic conditions as can be present in tumor or inflamed tissue. A prototype of a microrobot functionalized with the hydrogel is presented and proposed for the treatment of posterior eye diseases.

Design of alginate-based aerogel for nonsteroidal anti-inflammatory drugs controlled delivery systems using prilling and supercritical-assisted drying

In this study, a novel preparation method for alginate-based aerogels charged with nonsteroidal anti-inflammatory drugs (NSAIDs) was developed using prilling in combination with supercritical fluid technique. Nanoporous carriers were prepared by laminar jet breakup of drug/alginate solutions or suspensions followed by cross-linking in ethanol or aqueous CaCl(2) solutions, water replacement, and supercritical-CO(2) -assisted drying. A substantial drug loss was observed for highly soluble ketoprofen lysinate, whereas encapsulation efficiency was satisfying for slightly soluble ketoprofen. The tandem technique successfully produced almost spherical aerogels (sphericity coefficient 0.97-0.99) in narrow size distribution with reduced particle shrinkage and smooth surface (surface roughness 1.10-1.13); the internal porous texture of the parent hydrogels was preserved and appeared as a network of nanopores with diameters around 200 nm. Drug release profiles were monitored using a pH change method to evaluate the possible application of the aerogels as fast dissolving NSAIDs formulation. Aqueous cross-linking led to aerogels encapsulating ketoprofen in the amorphous form and with an enhanced burst effect in simulated gastric fluid (75% in 30 min), whereas ethanol cross-linking produced aerogels embedding drug in crystal clusters with slower dissolution rate. The system appears an interesting potential carrier for the fast delivery of slightly soluble drugs in the upper gastrointestinal tract.

Alginate graft copolymers and alginate-co-excipient physical mixture in oral drug delivery

OBJECTIVES

Use of alginate graft copolymers in oral drug delivery reduces dosage form manufacture complexity with reference to mixing or coating processes. It is deemed to give constant or approximately steady weight ratio of alginate to covalently attached co-excipient in copolymers, thereby leading to controllable matrix processing and drug release. This review describes various grafting approaches and their outcome on oral drug release behaviour of alginate graft copolymeric matrices. It examines drug release modulation mechanism of alginate graft copolymers against that of co-excipients in non-grafted formulations.

KEY FINDINGS

Drug release from alginate matrices can be modulated through using either co-excipients or graft copolymers via changing their swelling, erosion, hydrophobicity/hydrophilicity, porosity and/or drug adsorption capacity. However, it is not known if the drug delivery performance of formulations prepared using alginate graft copolymers is superior to those incorporating graft-equivalent co-excipient physically in a dosage form without grafting but at the corresponding graft weight, owing to limited studies being available.

CONCLUSIONS

The value of alginate graft copolymers as the potential alternative to alginate-co-excipient physical mixture in oral drug delivery cannot be entirely defined by past and present research. Such an issue is complicated by the lack of green chemistry graft copolymer synthesis approach, high grafting process cost, complications and hazards, and the formed graft copolymers having unknown toxicity. Future research will need to address these matters to achieve a widespread commercialization and industrial application of alginate graft copolymers in oral drug delivery.

Characterization of muco- and bioadhesive properties of chitosan, PVP, and chitosan/PVP blends and release of amoxicillin from alginate beads coated with chitosan/PVP

PURPOSE

To investigate the muco/bioadhesive properties of chitosan, polyvinylpyrrolidone (PVP), and chitosan/PVP blends and the release of amoxicillin (AMX) contained in AMX-alginate beads coated with these materials.

METHOD

Chitosan, PVP, and chitosan/PVP blends at various volume ratios were coated onto calcium alginate beads containing AMX. The muco/bioadhesive properties of all materials and the AMX-alginate beads coated with these materials were characterized.

RESULTS

Measurements of their viscosity, texture, and adhesion to HT29 cells demonstrated that chitosan/PVP at a volume ratio of 5/5 had the best muco/bioadhesive properties when compared with chitosan, PVP, and blends of other ratios. Wash-off tests indicated that the mucoadhesive property of the coated AMX-alginate beads was significantly higher than that of the uncoated beads. Diffuse reflectance infrared Fourier transform spectroscopy showed that there were interactions between chitosan-PVP, chitosan-mucin, PVP-mucin, and chitosan/PVP blend-mucin. Scanning electron microscopy revealed that the surfaces of the coated beads were smoother than those of the uncoated beads. All coated AMX-alginate beads were able to provide a controlled release of AMX with Super Case II transport properties, at a pH of 4. This was probably a result of the rapid and extensive swelling of the alginate beads. The more rapid release of AMX at pH 1 was probably because of the rapid dissolution of the drug at this pH.

CONCLUSIONS

From the controlled drug release and muco/bioadhesive properties of these coated AMX-alginate beads, we suggest that the alginate-coated beads might be a promising drug delivery system to assist with the eradication of Helicobacter pylori infections.