Influence of different classes of crosslinkers on alginate polyelectrolyte nanoparticle formation, thermodynamics and characteristics

An investigation of a strengthening polysaccharide interfacial membrane strategy utilizing an anionic polysaccharide-alkaline ligand interfacial assembly for all-liquid printing

The applications of polysaccharides as emulsifiers are limited due to the lack of hydrophobicity. However, traditional hydrophobic modification methods used for polysaccharides are complicated and involve significant mechanical and thermal losses. In this study, soy hull polysaccharide (SHP) and terminally aminopropylated polydimethylsiloxane (NPN) were selected to investigate the feasibility of a simple and green interfacial membrane strengthening strategy based on the interfacial polymerization of anionic polysaccharides and fat-soluble alkaline ligands. Our results show that deprotonated SHP and protonated NPN can be complexed at the water/oil (W/O) interface, reduce interfacial tension, and form a strong membrane structure. Moreover, they can quickly form a membrane at the W/O interface upon the moment of contact to produce stable all-liquid printing products with complex patterns. However, the molecular weight of NPN affects the complexation reaction. Consequently, this study has long-term implications to expanding the areas of application for anionic polysaccharides.

An ionically cross-linked composite hydrogel electrolyte based on natural biomacromolecules for sustainable zinc-ion batteries

Zinc-ion batteries (ZIBs) are regarded as promising power sources for flexible and biocompatible devices due to their good sustainability and high intrinsic safety. However, their applications have been hindered by the issues of uncontrolled Zn dendrite growth and severe water-induced side reactions in conventional liquid electrolytes. Herein, an ionically cross-linked composite hydrogel electrolyte based on natural biomacromolecules, including iota-carrageenan and sodium alginate, is designed to promote highly efficient and reversible Zn plating/stripping. The abundant functional groups of macromolecules effectively suppress the reactivity of water molecules and facilitate uniform Zn deposition. Moreover, the composite hydrogel electrolyte exhibits a high ionic conductivity of 5.89 × 10-2 S cm-1 and a Zn2+ transference number of 0.58. Consequently, the Zn‖Zn symmetric cell with the composite hydrogel electrolyte shows a stable cycle life of more than 500 h. Meanwhile, the Zn‖NH4V4O10 coin cell with the composite hydrogel electrolyte retains a high specific capacity of approximately 200 mA h g-1 after 600 cycles at 2 A g-1. The Zn‖NVO pouch cell based on the composite hydrogel electrolyte also shows a high specific capacity of 246.1 mA h g-1 at 0.5 A g-1 and retains 70.7% of its initial capacity after 150 cycles. The pouch cell performs well at different bending angles and exhibits a capacity retention rate of 98% after returning to its initial state from 180° folding. This work aims to construct high-performance hydrogel electrolytes using low-cost natural materials, which may provide a solution for the application of ZIBs in flexible biocompatible devices.

Advances in polysaccharides for probiotic delivery: Properties, methods, and applications

Probiotics are essential to improve the health of the host, whereas maintaining the viability of probiotics in harsh environments remains a challenge. Polysaccharides have non-toxicity, excellent biocompatibility, and outstanding biodegradability, which can protect probiotics by forming a physical barrier and show a promising prospect for probiotic delivery. In this review, we summarize polysaccharides commonly used for probiotic microencapsulation and introduce the microencapsulation technologies, including extrusion, emulsion, spray drying, freeze drying, and electrohydrodynamics. We discuss strategies for better protection of probiotics and introduce the applications of polysaccharides-encapsulated probiotics in functional food, oral formulation, and animal feed. Finally, we propose the challenges of polysaccharides-based delivery systems in industrial production and application. This review will help provide insight into the advances and challenges of polysaccharides in probiotic delivery.

Core-Shell Nanostructured Drug Delivery Platform Based on Biocompatible Metal-Organic Framework-Ligated Polyethyleneimine for Targeted Hepatocellular Carcinoma Therapy

Multifunctional nanosized metal-organic frameworks (NMOFs) have advanced rapidly over the past decade to develop drug delivery systems (DDSs). These material systems still lack precise and selective cellular targeting, as well as the fast release of the quantity of drugs that are simply adsorbed within and on the external surface of nanocarriers, which hinders their application in the drug delivery. Herein, we designed a biocompatible Zr-based NMOF with an engineered core and the hepatic tumor-targeting ligand, glycyrrhetinic acid grafted to polyethyleneimine (PEI) as the shell. The improved core-shell serves as a superior nanoplatform for efficient controlled and active delivery of the anticancer drug doxorubicin (DOX) against hepatic cancer cells (HepG2 cells). In addition to their high loading capacity of 23%, the developed nanostructure DOX@NMOF-PEI-GA showed an acidic pH-stimulated response and extended the drug release time to 9 days as well as enhanced the selectivity toward the tumor cells. Interestingly, the DOX-free nanostructures showed a minimal toxic effect on both normal human skin fibroblast (HSF) and hepatic cancer cell line (HepG2), but the DOX-loaded nanostructures exhibited a superior killing effect toward the hepatic tumor, thus opening the way for the active drug delivery and achieving efficient cancer therapy applications.

Rheological Considerations of Pharmaceutical Formulations: Focus on Viscoelasticity

Controlling rheological properties offers the opportunity to gain insight into the physical characteristics, structure, stability and drug release rate of formulations. To better understand the physical properties of hydrogels, not only rotational but also oscillatory experiments should be performed. Viscoelastic properties, including elastic and viscous properties, are measured using oscillatory rheology. The gel strength and elasticity of hydrogels are of great importance for pharmaceutical development as the application of viscoelastic preparations has considerably expanded in recent decades. Viscosupplementation, ophthalmic surgery and tissue engineering are just a few examples from the wide range of possible applications of viscoelastic hydrogels. Hyaluronic acid, alginate, gellan gum, pectin and chitosan are remarkable representatives of gelling agents that attract great attention applied in biomedical fields. This review provides a brief summary of rheological properties, highlighting the viscoelasticity of hydrogels with great potential in biomedicine.

ISOTHERMAL TITRATION CALORIMETRY (ITC) AS A PROMISING TOOL IN PHARMACEUTICAL NANOTECHNOLOGY

Isothermal titration calorimetry (ITC) is a technique for evaluating the thermodynamic profiles of connection between two molecules, allowing the experimental design of nanoparticles systems with drugs and/or biological molecules. Taking into account the relevance of ITC, we conducted, therefore, an integrative revision of the literature, from 2000 to 2023, on the main purposes of using this technique in pharmaceutical nanotechnology. The search were carried out in the Pubmed, Sciencedirect, Web of Science, and Scifinder databases using the descriptors "Nanoparticles", "Isothermal Titration Calorimetry", and "ITC". We have observed that the ITC technique has been increasingly used in pharmaceutical nanotechnology, seeking to understand the interaction mechanisms in the formation of nanoparticles. Additionally, to understand the behavior of nanoparticles with biological materials (proteins, DNA, cell membranes, among others), thereby helping to understand the behavior of nanocarriers in vivo studies. As a contribution, we intended to reveal the importance of ITC in the laboratory routine, which is itself a quick and easy technique to obtain relevant results that help to optimize the nanosystems formulation process.

L-Asparaginase delivery systems targeted to minimize its side-effects

L-asparaginase (L-ASP) is one of the key enzymes used in therapeutic applications, particularly to treat Acute Lymphocytic Leukemia (ALL). L-asparagine is a non-essential amino acid, which means that it can be synthesized by the body and is not required to be obtained through the diet. The synthesis of L-asparagine occurs primarily in the liver, but it also takes place in other tissues throughout the body. In contrast, leukemic cells cannot synthesize L-asparagine due the absence of L-asparagine synthetase and should obtain it from circulating sources for protein synthesis and cell division processes to ensure their vital functions. L-ASP catalyzes the deamination process of L-asparagine amino-acid into aspartic acid and ammonia, depriving leukemic cells of asparagine. This leads to decreased protein synthesis and cell division in tumor cells. However, using L-ASP has side effects, such as hypersensitivity or allergic reaction, antigenicity, short half-life, temporary blood clearance, and toxicity. L-ASP immobilization can minimize the side effects of L-ASP by stopping the immune system from attacking non-human enzymes and improving the enzyme's performance. The first strategy includes modification of enzyme structure, such as covalent binding (conjugation), adsorption to the support material and cross-linking of the enzyme. The chemical modification of residues, often nonspecific, changes the enzyme's hydrophobicity and surface charge, lowering the enzyme's activity. Also, the first strategy exposes the enzyme's surface to the environment. This eliminates its performance and does not allow targeted delivery of the enzyme. The second strategy is based on the entrapment of the enzyme inside the protecting structure or encapsulation. This strategy offers the same benefits as the first. Still, it also enables reducing toxicity, prolonging in vivo half-life, enhancing stability and activity, enables a targeted delivery and controlled release of the enzyme. Compared to the first strategy, encapsulation does not modify the chemical structure of the enzyme since L-ASP is only effective against leukemia in its native tetrameric form. This review aims to present state of the art in L-ASP formulations developed for reducing the side effects of L-ASP, focusing on describing improvements in their safety. The primary focus in the field remains to be improving the overall performance of the L-ASP formulations. Almost all encapsulation systems allow reducing immune response due to screening the enzyme from antibodies and prolonging its half-life. However, the enzyme's activity and stability depend on the encapsulation system type. Therefore, the selection of the right encapsulation system is crucial in therapy due to its effect on the performance parameters of the L-ASP. Biodegradable and biocompatible materials, such as chitosan, alginate and liposomes, mainly attract the researcher's interest in enzyme encapsulation. The research trends are also moving towards developing formulations with targeted delivery and increased selectivity.

Anionic Polysaccharide Cryogels: Interaction and In Vitro Behavior of Alginate-Gum Arabic Composites

In the present study, polysaccharide-based cryogels demonstrate their potential to mimic a synthetic extracellular matrix. Alginate-based cryogel composites with different gum arabic ratios were synthesized by an external ionic cross-linking protocol, and the interaction between the anionic polysaccharides was investigated. The structural features provided by FT-IR, Raman, and MAS NMR spectra analysis indicated that a chelation mechanism is the main process linking the two biopolymers. In addition, SEM investigations revealed a porous, interconnected, and well-defined structure suitable as a scaffold in tissue engineering. The in vitro tests confirmed the bioactive character of the cryogels through the development of the apatite layer on the surface of the samples after immersion in simulated body fluid, identifying the formation of a stable phase of calcium phosphate and a small amount of calcium oxalate. Cytotoxicity tests performed on fibroblast cells demonstrated the non-toxic effect of alginate-gum arabic cryogel composites. In addition, an increase in flexibility was noted for samples with a high gum arabic content, which determines an appropriate environment to promote tissue regeneration. The newly obtained biomaterials that exhibit all these properties can be successfully involved in the regeneration of soft tissues, wound management, or controlled drug release systems.

Development of pH-Responsive Polypills via Semi-Solid Extrusion 3D Printing

The low bioavailability of orally administered drugs as a result of the instability in the gastrointestinal tract environment creates significant challenges to developing site-targeted drug delivery systems. This study proposes a novel hydrogel drug carrier using pH-responsive materials assisted with semi-solid extrusion 3D printing technology, enabling site-targeted drug release and customisation of temporal release profiles. The effects of material parameters on the pH-responsive behaviours of printed tablets were analysed thoroughly by investigating the swelling properties under both artificial gastric and intestinal fluids. It has been shown that high swelling rates at either acidic or alkaline conditions can be achieved by adjusting the mass ratio between sodium alginate and carboxymethyl chitosan, enabling site-targeted release. The drug release experiments reveal that gastric drug release can be achieved with a mass ratio of 1:3, whilst a ratio of 3:1 allows for intestinal release. Furthermore, controlled release is realised by tuning the infill density of the printing process. The method proposed in this study can not only significantly improve the bioavailability of oral drugs, but also offer the potential that each component of a compound drug tablet can be released in a controlled manner at a target location.

Mucus-Penetrating Alginate-Chitosan Nanoparticles Loaded with Berberine Hydrochloride for Oral Delivery to the Inflammation Site of Ulcerative Colitis

The rectal enemas of berberine hydrochloride (BH) have emerged as one of the most effective strategies in the clinical treatment of ulcerative colitis (UC). However, oral dosages of BH exhibit a poor anti-inflammatory effect of UC, which may attribute to premature absorption of BH by the upper gastrointestinal tract. Moreover, the thick colonic mucus layer obstructs the penetration of the drug, resulting in low bioavailability to the inflammatory site of the colon. The aim of this study was to develop the mucus-penetrating sodium alginate-chitosan nanoparticles (SA-CS NPs) for oral delivery of BH to the site of colonic ulcer lesions. BH-loaded SA-CS NPs were developed through the ionic gelation method and analyzed for physicochemical characteristics, release performance, penetrability, site retention, and therapeutic efficacy. The results showed that the NPs have a particle size of 257 nm with a negative charge, presenting desired pH-dependent release behavior. The permeation studies elucidated that negatively charged SA-CS NPs had 2.9 times higher mucus penetration ability than positively charged CS NPs. An ex vivo retention study indicated the high retention of BH-SA-CS NPs at the colon site for more than 16 h. In vivo therapeutic effectiveness demonstrated that the prepared NPs could not only alleviate colonic injury by decreasing the disease activity index and colon mucosa damage index, but also improve the immunologic function by decreasing the spleen index. In conclusion, the BH-SA-CS NPs could enhance the mucus permeability and deliver drugs to the colonic inflammation site, providing new insights into improving the therapeutic effect of UC.

Emerging Technologies and Coating Materials for Improved Probiotication in Food Products: a Review

From the past few decades, consumers' demand for probiotic-based functional and healthy food products is rising exponentially. Encapsulation is an emerging field to protect probiotics from unfavorable conditions and to deliver probiotics at the target place while maintaining the controlled release in the colon. Probiotics have been encapsulated for decades using different encapsulation methods to maintain their viability during processing, storage, and digestion and to give health benefits. This review focuses on novel microencapsulation techniques of probiotic bacteria including vacuum drying, microwave drying, spray freeze drying, fluidized bed drying, impinging aerosol technology, hybridization system, ultrasonication with their recent advancement, and characteristics of the commonly used polymers have been briefly discussed. Other than novel techniques, characterization of microcapsules along with their mechanism of release and stability have shown great interest recently in developing novel functional food products with synergetic effects, especially in COVID-19 outbreak. A thorough discussion of novel processing technologies and applications in food products with the incorporation of recent research works is the novelty and highlight of this review paper.

Bioprinting Au Natural: The Biologics of Bioinks

The development of appropriate bioinks is a complex task, dependent on the mechanical and biochemical requirements of the final construct and the type of printer used for fabrication. The two most common tissue printers are micro-extrusion and digital light projection printers. Here we briefly discuss the required characteristics of a bioink for each of these printing processes. However, physical printing is only a short window in the lifespan of a printed construct-the system must support and facilitate cellular development after it is printed. To that end, we provide a broad overview of some of the biological molecules currently used as bioinks. Each molecule has advantages for specific tissues/cells, and potential disadvantages are discussed, along with examples of their current use in the field. Notably, it is stressed that active researchers are trending towards the use of composite bioinks. Utilizing the strengths from multiple materials is highlighted as a key component of bioink development.

Integrated ‘all-in-one’ strategy to stabilize zinc anodes for high-performance zinc-ion batteries

Many optimization strategies have been employed to stabilize zinc anodes of zinc-ion batteries (ZIBs). Although these commonly used strategies can improve anode performance, they simultaneously induce specific issues. In this study, through the combination of structural design, interface modification, and electrolyte optimization, an ‘all-in-one’ (AIO) electrode was developed. Compared to the three-dimensional (3D) anode in routine liquid electrolytes, the new AIO electrode can greatly suppress gas evolution and the occurrence of side reactions induced by active water molecules, while retaining the merits of a 3D anode. Moreover, the integrated AIO strategy achieves a sufficient electrode/electrolyte interface contact area, so that the electrode can promote electron/ion transfer, and ensure a fast and complete redox reaction. As a result, it achieves excellent shelving-restoring ability (60 hours, four times) and 1200 cycles of long-term stability without apparent polarization. When paired with two common cathode materials used in ZIBs (α-MnO₂ and NH₄V₄O₁₀), full batteries with the AIO electrode demonstrate high capacity and good stability. The strategy of the ‘all-in-one’ architectural design is enlightened to solve the issues of zinc anodes in advanced Zn-based batteries.

Marine Polysaccharides as a Versatile Biomass for the Construction of Nano Drug Delivery Systems

Marine biomass is a treasure trove of materials. Marine polysaccharides have the characteristics of biocompatibility, biodegradability, non-toxicity, low cost, and abundance. An enormous variety of polysaccharides can be extracted from marine organisms such as algae, crustaceans, and microorganisms. The most studied marine polysaccharides include chitin, chitosan, alginates, hyaluronic acid, fucoidan, carrageenan, agarose, and Ulva. Marine polysaccharides have a wide range of applications in the field of biomedical materials, such as drug delivery, tissue engineering, wound dressings, and sensors. The drug delivery system (DDS) can comprehensively control the distribution of drugs in the organism in space, time, and dosage, thereby increasing the utilization efficiency of drugs, reducing costs, and reducing toxic side effects. The nano-drug delivery system (NDDS), due to its small size, can function at the subcellular level in vivo. The marine polysaccharide-based DDS combines the advantages of polysaccharide materials and nanotechnology, and is suitable as a carrier for different pharmaceutical preparations. This review summarizes the advantages and drawbacks of using marine polysaccharides to construct the NDDS and describes the preparation methods and modification strategies of marine polysaccharide-based nanocarriers.

Treatment challenges and delivery systems in immunomodulation and probiotic therapies for periodontitis

Introduction: Periodontitis is a widespread illness that arises due to disrupted interplay between the oral microbiota and the host immune response. In some cases, conventional therapies can provide temporary remission, although this is often followed by disease relapse. Recent studies of periodontitis pathology have promoted the development of new therapeutics to improve treatment options, together with local application using advanced drug delivery systems.Areas covered: This paper provides a critical review of the status of current treatment approaches to periodontitis, with a focus on promising immunomodulation and probiotic therapies. These are based on delivery of small molecules, peptides, proteins, DNA or RNA, and probiotics. The key findings on novel treatment strategies and formulation of advanced delivery systems, such as nanoparticles and nanofibers, are highlighted.Expert opinion: Multitarget therapy based on antimicrobial, immunomodulatory, and probiotic active ingredients incorporated into advanced delivery systems for application to the periodontal pocket can improve periodontitis treatment outcomes. Translation of such adjuvant therapy from laboratory to patient is expected in the future.

Development and microbiological evaluation of chitosan and chitosan-alginate microspheres for vaginal administration of metronidazole

Metronidazole is the drug of choice in the treatment of bacterial vaginosis, but the oral therapy can induce several collateral effects. Aim of this work was the development of a vaginal multiparticulate system, loaded with metronidazole, able to improve its residence time allowing a complete drug release. Several kinds of MS were prepared using chitosan dissolved in different organic acids or alginate coated with chitosan. FTIR and DSC analyses were performed to study the interactions between the drug and the polymers, while MS morphology was investigated with optical and electron microscopy. All the formulations were characterized in terms of drug entrapment efficiency, mucoadhesion, swelling capacity and drug release behavior, demonstrating the best results for alginate MS coated with chitosan. The formulations evidenced a complete and rapid release of drug, compared with the commercial form: Zidoval®.The best formulations assayed for antibacterial activity confirmed the suitability of this new formulation for the vaginal treatment of local diseases.

Current Status of Alginate in Drug Delivery

Alginate is one of the natural polymers that are often used in drug- and protein-delivery systems. The use of alginate can provide several advantages including ease of preparation, biocompatibility, biodegradability, and nontoxicity. It can be applied to various routes of drug administration including targeted or localized drug-delivery systems. The development of alginates as a selected polymer in various delivery systems can be adjusted depending on the challenges that must be overcome by drug or proteins or the system itself. The increased effectiveness and safety of sodium alginate in the drug- or protein-delivery system are evidenced by changing the physicochemical characteristics of the drug or proteins. In this review, various routes of alginate-based drug or protein delivery, the effectivity of alginate in the stem cells, and cell encapsulation have been discussed. The recent advances in the in vivo alginate-based drug-delivery systems as well as their toxicities have also been reviewed.

Polyelectrolyte-surfactant-complex nanoparticles as a delivery platform for poorly soluble drugs: A case study of ibuprofen loaded cetylpyridinium-alginate system

Previously, we reported on the surfactant cetylpyridinium chloride (CPC) as a crosslinker of alginate for the formation of stable polyelectrolyte-surfactant-complex nanoparticles. Here, we evaluate this system for increased solubility of a poorly soluble drug. The aim was to use CPC for solubilisation of ibuprofen and to use the micellar associates formed for alginate complexation and nanoparticle formation. We acquired deeper insights into the entropy led interactions between alginate, CPC and ibuprofen. Stable nanoparticles were formed across limited surfactant-to-polyelectrolyte molar ratios, with ~150 nm hydrodynamic diameter, monodispersed distribution, and negative zeta potential (-40 mV), with 34% ibuprofen loading. Their structure was obtained using small-angle X-ray scattering, which indicated disordered micellar associates when ibuprofen was incorporated. This resulted in nanoparticles with a complex nanostructured composition, as shown by transmission electron microscopy. Drug release from ibuprofen-cetylpyridinium-alginate nanoparticles was not hindered by alginate, and was similar to the release kinetics from ibuprofen-CPC solubilisates. These innovative carriers developed as polyelectrolyte-surfactant complexes can be used for solubilisation of poorly soluble drugs, where the surfactant simultaneously increases the solubility of the drug at concentrations below its critical micellar concentration and crosslinks the polyelectrolyte to form nanoparticles.

Chitosan-based Colloidal Polyelectrolyte Complexes for Drug Delivery: A Review

Polyelectrolyte complexes (PECs) as safe drug delivery carriers, are spontaneously formed by mixing the oppositely charged polyelectrolyte solutions in water without using organic solvents nor chemical cross-linker or surfactant. Intensifying attentions on the PECs study are aroused in academia and industry since the fabrication process of PECs is mild and they are ideal vectors for the delivery of susceptible drugs and macromolecules. Chitosan as the unique natural cationic polysaccharide, is a good bioadhesive material. Besides, due to its excellent biocompatibility, biodegradability, abundant availability and hydrophilic nature, chitosan-based PECs have been extensively applied for drug delivery, particularly after administration through mucosal and parenteral routes. The purpose of this review is to compile the recent advances on the biomedical applications of chitosan-based PECs, with specific focuses on the mucosal delivery, cancer therapy, gene delivery and anti-HIV therapy. The challenges and the perspectives of the chitosan-based PECs are briefly commented as well.

Effect of Solution Composition Variables on Electrospun Alginate Nanofibers: Response Surface Analysis

Alginate is a promising biocompatible and biodegradable polymer for production of nanofibers for drug delivery and tissue engineering. However, alginate is difficult to electrospin due to its polyelectrolyte nature. The aim was to improve the 'electrospinability' of alginate with addition of exceptionally high molecular weight poly(ethylene oxide) (PEO) as a co-polymer. The compositions of the polymer-blend solutions for electrospinning were varied for PEO molecular weight, total (alginate plus PEO) polymer concentration, and PEO proportion in the dry alginate-PEO polymer mix used. These were tested for rheology (viscosity, complex viscosity, storage and loss moduli) and conductivity, and the electrospun nanofibers were characterized by scanning electron microscopy. One-parameter-at-a-time approach and response surface methodology (RSM) were used to optimize the polymer-blend solution composition to obtain defined nanofibers. Both approaches revealed that the major influence on nanofiber formation and diameter were total polymer concentration and PEO proportion. These polymer-blend solutions of appropriate conductivity and viscosity enabled fine-tuning of nanofiber diameter. PEO molecular weight of 2-4 million Da greatly improved the electrospinnability of alginate, producing nanofibers with >85% alginate. This study shows that RSM can be used to design nanofibers with optimal alginate and co-polymer contents to provide efficient scaffold material for regenerative medicine.

Promising Chitosan-Coated Alginate-Tween 80 Nanoparticles as Rifampicin Coadministered Ascorbic Acid Delivery Carrier Against Mycobacterium tuberculosis

The aim of this study was to design a nanocarrier system for inhalation delivery of rifampicin (RIF) in combination with ascorbic acid (ASC), namely constituted of sodium alginate coated with chitosan and Tween 80 (RIF/ASC NPs) as a platform for the treatment of pulmonary tuberculosis infection. A Box-Behnken experimental design and response surface methodology (RSM) were applied to elucidate and evaluate the effects of several factors on the nanoparticle properties. On the other hand, it was found that RIF/ASC NPs were less cytotoxic than the free RIF, showing a significantly improved activity against nine clinical strains of Mycobacterium tuberculosis (M. tb) in comparison with the free drug. RIF/ASC NPs had an average particle size of 324.0 ± 40.7 nm, a polydispersity index of 0.226 ± 0.030, and a zeta potential of - 28.52 ± 0.47 mV and the surface was hydrophilic. The addition of sucrose (1% w/v) to the nanosuspension resulted in the formation of a solid pellet easily redispersible after lyophilization. RIF/ASC NPs were found to be stable at different physiological pH values. In summary, findings of this work highlight the potential of the RIF/ASC NP-based formulation development herein to deliver RIF in combination with ASC through pulmonary route by exploring a non-invasive route of administration of this antibiotic, increasing the local drug concentrations in lung tissues, the primary infection site, as well as reducing the risk of systemic toxicity and hence improving the patient compliance.

Effect of surface hydrophobicity of therapeutic protein loaded in polyelectrolyte nanoparticles on transepithelial permeability

Oral delivery of protein drugs is greatly limited by low hydrophobicity, an important determinant for intestinal epithelial permeation and bioavailability. Herein, surface properties of recombinant erythropoietin were investigated using the fluorescent dye bis-ANS to monitor relative hydrophobicity for correlation with permeabilities with Caco-2 cells. At various pHs, bis-ANS fluorescence intensity indicated different surface hydrophobicities of erythropoietin molecules. Erythropoietin incorporated in chitosan or chitosan-trimethylchitosan (CS-TMC) nanoparticles prepared by polyelectrolyte complexation and ionotropic gelation with tripolyphosphate also showed different surface hydrophobicities. Chitosan nanoparticles with erythropoietin provided the most hydrophobic surface, followed by free erythropoietin (in water) and that loaded into CS-TMC nanoparticles. Chitosan nanoparticles were more effective than CS-TMC nanoparticles for permeation of erythropoietin across Caco-2 cell monolayers; the lowest permeability was shown by erythropoietin itself. Thus, hydrophilic protein molecules complexed with polyelectrolytes can provide more hydrophobic surfaces that enhance transepithelial permeability. This bis-ANS method also provides valuable information for the design of polyelectrolyte nanoparticules for oral delivery of protein drugs.

Preparation, characterization and in vitro release of β-galactosidase loaded polyelectrolyte nanoparticles

Improving encapsulation efficacy (EE) and bioavailability of β-galactosidase (β-gal) is always a challenge due to its fragility. In this work, β-gal loaded β-chitosan (CS) nanoparticles (NPs) were successfully prepared based on ionic gelation technique and electrostatic attraction for improving its EE and in vitro releasing capacity. The particle size of β-gal loaded low and high molecular weight (LMW and HMW) β-CS NPs reached 584.37 and 652.46nm, with Zeta-potential (ZP) of 26.37 and 16.46mV under the optimal conditions, respectively. In vitro release study conducted at pH4.5 and 7.4 showed that β-gal loaded LMW and HMW β-CS NPs with EE of 68.32 and 58.64% sustained the release of the β-gal over 12h. The β-gal incorporated into β-CS NPs was confirmed with the results of physicochemical and structural properties of β-gal loaded β-CS NPs, and prepared NPs had hardly any cytotoxicity in the range of 0.1-1.0mg/mL. The results indicated that β-gal loaded β-CS NPs could serve as non-toxic delivery carriers for the treatment of lactose intolerance.