Optimizing the chitosan-cellulose based drug delivery system for controlling the ciprofloxacin release versus organic/inorganic crosslinker, characterization and kinetic study

Opportunity for valorization of pulping by-product in production high performance sustaining release lignin-based gel

This study focuses on optimizing the pulping by-product to produce effective hydrogels for controlling the release of salicylic acid (SA). In this regard, two routes are achieved: the first involves preparing black liquor (BL) composite hydrogels with various polymer macromolecules [polyacrylamide (PAM), polyvinyl alcohol (PVA), and chitosan (Cs), and the second involves carboxymethylation of BL and grafting with acrylamide. Hydrogels are evaluated using spectral analysis (ATR-FTIR), thermal analysis (TGA and DTG), and swelling measures. Encapsulation, release profile, SA release kinetics, as well as ATR-FTIR and SEM measurements, were used to evaluate the behavior of loaded hydrogels. According to the results, grafted carboxymethylated BL-gel had the maximum SA release (98.7 %), followed by PAM-BL (51.7 %) and PAM/PVA-BL (43.1 %). Over a 48-hour period, the hydrogels demonstrated a prolonged SA release pattern. The Ritger-Peppas and Higuchi models fitted to all examined hydrogels showed that SA release followed both Fickian and non-Fickian diffusion pathways.

Intestinal-specific oral delivery of lactoferrin with alginate-based composite and hybrid CaCO3-hydrogel beads

Sodium alginate hydrogel beads and sodium alginate/gellan gum composite hydrogel beads crosslinked by calcium chloride were prepared with different alginate concentrations (3-20 mg·mL-1). Additionally, a simple method for growing CaCO3in situ on the hydrogel to create novel inorganic-organic hybrid hydrogel beads was presented. FT-IR analysis revealed the involvement of hydrogen bonding and electrostatic interactions in bead formation. Swelling behavior in acidic conditions showed a maximum of 13 g/g for composite hydrogels and CaCO3-incorporated hybrid hydrogels. Lactoferrin encapsulation efficiency within these hydrogels ranged from 44.9 to 56.6%. In vitro release experiments demonstrated that these hydrogel beads withstand harsh gastric environments with <16% cumulative release of lactoferrin, achieving controlled release in intestinal surroundings. While composite sodium alginate/gellan gum beads exhibited slower gastrointestinal lactoferrin digestion, facile synthesis and pH responsiveness of CaCO3-incorporated hybrid hydrogel also provide new possibilities for future studies to construct a novel inorganic-organic synergetic system for intestinal-specific oral delivery.

Stability and release mechanism of double emulsification (W1/O/W2) for biodegradable pH-responsive polyhydroxybutyrate/cellulose acetate phthalate microbeads loaded with the water-soluble bioactive compound niacinamide

Microbeads of biodegradable polyhydroxybutyrate (PHB) offer environmental benefits and economic competitiveness. The aim of this study was to encapsulate a water-soluble bioactive compound, niacinamide (NIA), in a pH-responsive natural matrix composed of PHB and cellulose acetate phthalate (CAP) by double emulsification (W1/O/W2) to improve the encapsulation efficiency (%EE) and loading capacity (%LC). PHB was produced in-house by Escherichia coli JM109 pUC19-23119phaCABA-04 without the inducing agent isopropyl β-D-1-thiogalactopyranoside (IPTG). The influences of PHB and polyvinyl alcohol (PVA) concentrations, stirring rate, PHB/CAP ratio and initial NIA concentration on the properties of NIA-loaded pH-responsive microbeads were studied. The NIA-loaded pH-responsive PHB/CAP microbeads exhibited a spherical core-shell structure. The average size of the NIA-loaded pH-responsive microbeads was 1243.3 ± 11.5 μm. The EE and LC were 33.3 ± 0.5 % and 28.5 ± 0.4 %, respectively. The release profiles of NIA showed pH-responsive properties, as 94.2 ± 3.5 % of NIA was released at pH 5.5, whereas 99.3 ± 2.4 % of NIA was released at pH 7.0. The NIA-loaded pH-responsive PHB/CAP microbeads were stable for >90 days at 4 °C under darkness, with NIA remaining at 73.65 ± 1.86 %. A cytotoxicity assay in PSVK1 cells confirmed that the NIA-loaded pH-responsive PHB/CAP microbeads were nontoxic at concentrations lower than 31.3 μg/mL, in accordance with ISO 10993-5.

Electric-field-sensitive hydrogel based on pineapple peel oxidized hydroxyethyl cellulose/gelatin/Hericium erinaceus residues chitosan and its study in curcumin delivery

This study focused on synthesis of innovative hydrogels with electric field response from modified pineapple peel cellulose and hericium erinaceus chitosan and gelatin based on Schiff base reaction. A series of hydrogels were prepared by oxidized hydroxyethyl cellulose, gelatin and chitosan at different deacetylation degree via mild Schiff base reaction. Subsequently experiments towards the characterization of oxidized hydroxyethyl cellulose/gelatin/chitosan (OHGCS) hydrogel polymers were carried out by FTIR/XRD/XPS, swelling performances and electric response properties. The prepared hydrogels exhibited stable and reversible bending behaviors under repeated on-off switching of electric fields, affected by ionic strength, electric voltage and pH changes. The swelling ratio of OHGCS hydrogels was found reduced as deacetylation degree increasing and reached the maximum ratio ∼ 2250 % for OHGCS-1. In vitro drug releasing study showed the both curcumin loading capacity and release amount of Cur-OHGCS hydrogels arrived about 90 % during 6 h. Antioxidation assessments showed that the curcumin-loaded hydrogels had good antioxidation activities, in which, 10 mg Cur-OHGCS-1 hydrogel could reach to the maximum of about 90 % DPPH scavenging ratio. These results indicate the OHGCS hydrogels have potentials in sensor and drug delivery system.

Development of Poly(vinyl alcohol)-Chitosan Composite Nanofibers for Dual Drug Therapy of Wounds

Current trends in localized drug delivery are emphasizing the development of dual drug-loaded electrospun nanofibers (NFs) for an improved therapeutic effect on wounds, especially infected skin wounds. The objective of this study was to formulate a new healing therapy for an infected skin wound. To achieve this goal, this study involved the development and characterization of poly(vinyl alcohol) (PVA)/chitosan nanofibers loaded with ciprofloxacin and rutin hydrate. Polymers and drugs were used in different ratios. Nanofiber morphology was studied by scanning electron microscopy, thermal stability by thermogravimetric analysis, structural determination by the X-ray diffraction method, and integrity by Fourier transform infrared spectroscopy. Dissolution studies were performed to check the drug release behavior of the formulations. Antibacterial studies were performed against Staphylococcus aureus and Pseudomonas aeruginosa. The wound healing efficiency of dual drug-loaded nanofibers was measured by a full-thickness excisional wound model of rabbits. The fabricated nanofibers were smooth in morphology. According to FTIR findings, the drugs remained intact in the nanofibers. The results of swelling ratio and porosity revealed that the pore size was increased as the amount of chitosan was increased up to 30% but a further increase in chitosan concentration reduced the swelling ratio and porosity. Drug release studies of nanofibers depicted an initial burst effect and afterward controlled drug release behavior. Drug-loaded nanofibers showed better activity against S. aureus than P. aeruginosa. The antibacterial efficacy of rutin hydrate with ciprofloxacin was improved compared to that of the formulation having rutin hydrate only, likely due to the additive effect in activity. Based on wound healing studies, nanofibrous membranes acted as a promising wound dressing material as compared to the commercial wound healing formulation. Drug-loaded polymeric nanofibers were successfully fabricated by using an electrospinning method. These nanofibers showed an efficient ability to deliver drugs and treat infected wounds.

Self-triggered carboxymethyl chitosan hydrogel for the convenient sustained release of ClO2 gas with environmental stability and long-term antimicrobial effect

Challenges associated with the storage and uncontrolled release of ClO2 gas present significant hurdles to its practical application. Herein, a clever strategy for self-triggering the sustained release of chlorine dioxide (ClO2) gas is proposed by crosslinking carboxymethyl chitosan (CMCS) with Zn2+ to construct a novel CMCS-Zn@NaClO2 gel with eco-friendly, environmental stability, and convenient, long term, and efficient antibacterial activity. The precursor (NaClO2) in the CMCS solution was alkaline and triggered by the acidic Zn(NO3)2·6H2O solution to achieve sustained self-triggering ClO2 release. The ClO2 gas self-release could be sustained on demand at different temperatures for at least 20 days due to the environmental structure stability of the gel. The hydrogels showed an increase in pore size after sustained release. Molecular dynamics simulations showed the spontaneous release of ClO2 gas at room temperature and the contraction of the CMCS agglomeration, which were consistent with the macroscopic behaviour. The gel displayed a long-acting and high antibacterial efficacy, resulting in a bacteria-killing rate of over 99.9% (inhibitory concentrations of 2.5 mg mL-1 against E. coli and 0.16 mg mL-1 against S. aureus). The hydrogels could effectively extend the shelf life of fruits and demonstrated an excellent wide range of antibacterial properties. This work provides a new approach to solving the storage difficulty of ClO2 gas and offers a fresh perspective on the design of materials with convenient self-triggering release by a precursor, as well as the relationship between the material microstructure and sustained-release behaviour.

Chitosan coated graphene oxide incorporated sodium alginate hydrogel beads for the controlled release of amoxicillin

Biopolymers are crucial in pharmaceuticals, particularly for controlled drug release. In this study, we loaded the broad-spectrum antibacterial drug amoxicillin into sodium alginate, a well-known biopolymer. Graphene oxide was incorporated into the composite, and the hydrogel beads were coated with chitosan for its mucoadhesive properties. Various composites were formulated by adjusting the weight percentage of graphene oxide (GO). The fabricated beads demonstrated controlled and sustained drug release, with 98 % of the loaded drug molecules released over 24 h at gastric pH. The antibacterial test using the disc diffusion technique confirmed the drug release, exhibiting greater effectiveness against the gram-positive bacterium S. aureus than the gram-negative bacterium E. coli. The drug release data were optimized using zero order, first order, Higuchi, and Korsmeyer-Peppas models. The experimental data were best fit to the Korsmeyer-Peppas model with a relatively higher correlation coefficient value. Biocompatibility was evaluated through a cell viability test using mouse fibroblast cell lines (L929). The MTT viability assay confirmed high levels of cytocompatibility, even at higher concentrations (100 μg/mL), with 98.15 % viable cells. These results highlight the potential of the fabricated beads as an effective amoxicillin drug delivery system with biomedical applications.

Sustained drug release behavior of captopril-incorporated chitosan/carboxymethyl cellulose biomaterials for antihypertensive therapy

Captopril (CTP) is an oral drug widely used to treat high blood pressure and congestive heart failure. In this study, CTP-incorporated biomaterials for antihypertensive therapy were synthesized from chitosan, carboxymethyl cellulose, and plasticizers. The physicochemical properties of the prepared biomaterials were characterized using FE-SEM, FT-IR analysis, and physical properties. CTP release experiments were carried out in buffer solutions at various pH values and temperatures. Results indicated that above 99.0 % of CTP was released within 180 min. Optimization of the experimental conditions for CTP release was analyzed by using response surface methodology (RSM). Results of CTP release through artificial skin indicated that CTP was continuously released above 95.0 % from the prepared biomaterials for 36.0 h. The CTP release mechanisms into a buffer and through artificial skin followed pseudo-Fickian diffusion mechanism and non-Fickian diffusion mechanisms, respectively. Moreover, angiotensin-converting enzyme (ACE) inhibition (related to cardiovascular disease) via the released CTP clearly reveals that the prepared biomaterials have a high potential as a transdermal drug delivery agent in antihypertensive therapy.

Cellulosic wastepaper modified starch/ itaconic acid/ acrylic acid-based biodegradable hydrogel as a sustain release of NPK fertilizer vehicle for agricultural applications

In this work, wastepaper powder was used as a modifying agent for a biodegradable hydrogel composite of starch, itaconic acid, and acrylic acid. After the addition of an optimum amount of the modifying agent, the swelling ability of the hydrogel was enhanced from 503 g/g to 647 g/g. Further, the hydrogel was also used for sustained release of NPK fertilizer and subsequent effect of the fertilizer loaded hydrogel in okra seed germination was also studied. The NPK loaded-hydrogel showed good sustained-release behavior and 98 % of N, 81 % of P and 95 % of K release were observed after 20th day of incubation. Moreover, the release study was explained by using different kinetic models. In seed germination study, a higher and faster germination rate for okra seeds was observed in case of NPK loaded hydrogel compared to the control system, which was attributed to the synergistic effect of essential macronutrients (N, P, and K) and water that were inside the hydrogel. Most importantly, the hydrogel was found to be biodegradable by using soil burial method and further confirmed by FTIR and SEM analyses. Thus, this work provides an efficient way for utilization of wastepaper in the production of a biodegradable hydrogel for agricultural applications.

A review of cellulose-based derivatives polymers in fabrication of gas separation membranes: Recent developments and challenges

Due to low-cost, sustainability and good mechanical stability, cellulose-based materials are frequently used in fabrication of polymeric gas separation membrane as potential carbohydrate polymers to substitute traditional petrochemical-based materials. In this review, the performance of cellulose-based polymeric membranes i.e. cellulose acetate, cellulose diacetate, cellulose triacetate, ethyl cellulose and carboxymethyl cellulose in the separation of different gases were investigated. This review paper provides the main features and advantages in the fabrication of cellulose-based gas separation membranes. The influence of the functionalization of cellulose on gas separation and permeability performance of related membranes is considered. Influence of different modification procedures such as blending with polymers, nanomaterials and ionic liquids on the gas separation ability of cellulose-based membranes were reviewed. Moreover, a brief inquiry of the potential of cellulose-based gas separation membranes for industrial applications, by examining the performance of different cellulose derivatives and identifying potential strategies for membrane modification and optimization are given, along with the current restrictions and the future perspectives are discussed.

Guard against internal and external: An antibacterial, anti-inflammation and healing-promoting spray gel based on lyotropic liquid crystals for the treatment of diabetic wound

The diabetic wound is a prevalent and serious complication of diabetes, which easily deteriorates due to susceptibility to infection and difficulty in healing, causing a high risk of amputation and economic burden to patients. Bacterial infection, persistent excessive inflammation, and cellular and angiogenesis disorders are the main reasons for the difficulty of diabetic wound healing. In this study, glycerol monooleate (GMO) was used to prepare lyotropic liquid crystal hydrogel (LLC) containing the natural antimicrobial peptide LL37 and carbenoxolone (CBX) to achieve antibacterial, anti-inflammation, and healing promotion for the treatment of diabetic wounds. The shear-thinning properties of the LLC precursor solution allowed it to be administered in the form of a spray, which perfectly fitted the shape of the wound and transformed into a gel after absorbing wound exudate to act as a wound protective barrier. The faster release of LL37 realized rapid sterilization of wounds, controlled the source of inflammation, and accelerated wound healing. The inflammatory signaling pathway was blocked by the subsequently released CBX, and the spread of the inflammatory response was inhibited and then further weakened. In addition, CBX down-regulated connexin (Cx43) to assist LL37 to promote cell migration and proliferation better. Combined with the pro-angiogenic effect of LL37, the healing of diabetic wounds was significantly accelerated. All these advantages made LL37-CBX-LLC a promising approach for the treatment of chronic diabetic wounds.

The emergence of hybrid cellulose nanomaterials as promising biomaterials

Cellulose nanomaterials (CNs) are promising green materials due to their unique properties as well as their environmental benefits. Among these materials, cellulose nanofibrils (CNFs) and nanocrystals (CNCs) are the most extensively researched types of CNs. While they share some fundamental properties like low density, biodegradability, biocompatibility, and low toxicity, they also possess unique differentiating characteristics such as morphology, rheology, aspect ratio, crystallinity, mechanical and optical properties. Therefore, numerous comparative studies have been conducted, and recently, various studies have reported the synergetic advantages resulting from combining CNF and CNC. In this review, we initiate by addressing the terminology used to describe combinations of these and other types of CNs, proposing "hybrid cellulose nanomaterials" (HCNs) as the standardized classifictation for these materials. Subsequently, we briefly cover aspects of properties-driven applications and the performance of CNs, from both an individual and comparative perspective. Next, we comprehensively examine the potential of HCN-based materials, highlighting their performance for various applications. In conclusion, HCNs have demonstraded remarkable success in diverse areas, such as food packaging, electronic devices, 3D printing, biomedical and other fields, resulting in materials with superior performance when compared to neat CNF or CNC. Therefore, HCNs exhibit great potential for the development of environmentally friendly materials with enhanced properties.

Fabrication, Properties, and Stability of Oregano Essential Oil and Sodium Alginate-Based Wound-Healing Hydrogels

The wound dressings fabricated by polymers and oregano essential oil (OEO) can be very effective as a hydrogel. The current study has been focused on fabricating the hydrogel membranes of oregano oil encapsulated as an antibacterial agent into sodium alginate (SA) solution by solvent casting method and then evaluated the antibacterial, antioxidant activity, and physicochemical performance of SA/OEO-based polymeric membranes. The polymeric interactions, surface morphology, water absorption capability, thermal stability, and encapsulation efficiency were investigated by FT-IR, SEM, swelling ratio, DSC, and encapsulation efficiency. The percentage encapsulation efficiency of essential oil was 40.5%. FTIR validated the presence of molecular interaction between individual components. SEM images showed a rough and porous appearance for hydrogel membranes. Moreover, DSC showed that the fabricated membranes were thermally stable. The inclusion of more content OEO decreased swelling ratios. The antioxidant test was carried out by DPPH assay and antibacterial test through disc diffusion method against microbes. The results revealed that membranes containing the highest content of OEO had more excellent antioxidant and antibacterial efficacy. Therefore, the polymeric membranes of sodium alginate loaded with oregano essential oil can be employed as an effective wound-healing candidate.

pH-responsive magnetic biocompatible chitosan-based nanocomposite carrier for ciprofloxacin release

The pH-sensitive and magnetic-triggered release ensures the effective delivery of drugs. Chitosan carries amine pendants that encourage the fabrication of pH-responsive carriers. Montmorillonite (MMt), an attractive nano-clay in drug delivery possessing high encapsulation properties, was magnetized through the co-precipitation of Fe3+/Fe2+ ions. The study aimed to integrate the magnetic montmorillonite (mMMt) into the chitosan matrix and crosslinked by citric acid (CA) to achieve the nanocomposite carrier with double-responsive features for effective drug delivery. The release evaluation revealed that coating the mMMt with CA-crosslinked chitosan prevented the burst release of Ciprofluxcacin (Cip). The nanocomposite showed a high sustained release, and the release rate in the neutral environment (pH 7.4) was remarkably higher than in acidic media (pH 5.8). The new nanocomposite carrier showed high encapsulation efficiency to Cip (about 98 %). The study was developed by investigating external magnetic effects on the release rate, which lead to an increase in the release rate. The kinetics studies confirmed the diffusion mechanism for Cip release in all experimental media. The Cip-loaded nanocomposite carriers showed antibacterial activity against E. coli and S. aureus.

Upcycling polyethylene terephthalate wastes for enhancing the performance of polyester from rice straw polyol in HDPE-composites

Upscaling the utilization of polymer wastes together with the valorization of undesirable waste rice straw (RS) will minimize the environmental impact of waste disposal by traditional tools. This present work assesses the utilization of polyethylene terephthalate wastes in enhancing the production of polyester-(high density polyethylene) HDPE from Rice straw polyol composites. In this respect, the polyester from rice straw polyol in hybrid with glycolysis polyethylene terephthalate wastes (Gly-WPET) was assessed in comparison with that resulted from RS-polyol, using FTIR, non-isothermal analysis, and mechanical tests. The data showed the positive role of Gly-WPET in hybrid with RS-polyol in production polyester with high thermal stability and mechanical properties. It provided an increase in activation energy of degradation, elongation, Young's Modulus, and modulus of toughness from 184.5 to 1201 kJ/mole, from 4.7 to 9.8%, from 47.5 to 66.5 MPa, and from ~ 4.0 to 23 J/m3, respectively. This behavior was reflected in the properties of HDPE-polyester polyol (PEPO) composites, especially in improving elongation (from 55.4 to 72%). These promising data persuade us to recommend the influential role of Gly-WPET in using PEPO from liquefied RS as a plasticizer.

Polymer based dual drug delivery system for targeted treatment of fluoroquinolone resistant Staphylococcus aureus mediated infections

The present study attempts to treat S. aureus-induced soft skin infections using a combinatorial therapy with an antibiotic, Ciprofloxacin (CIP), and an efflux pump inhibitor 5-Nitro-2-(3-phenylpropoxy) pyridine (5-NPPP) through a smart hydrogel delivery system. The study aims to reduce the increasing rates of infections and antimicrobial resistance; therefore, an efflux pump inhibitor molecule is synthesized and delivered along with an antibiotic to re-sensitize the pathogen towards antibiotics and treat the infections. CIP-loaded polyvinyl alcohol (PVA) hydrogels at varying concentrations were fabricated and optimized by a chemical cross-linking process, which exhibited sustained drug release for 5 days. The compound 5-NPPP loaded hydrogels provided linear drug release for 2 days, necessitating the need for the development of polymeric nanoparticles to alter the release drug pattern. 5-NPPP loaded Eudragit RSPO nanoparticles were prepared by modified nanoprecipitation-solvent evaporation method, which showed optimum average particle size of 230-280 nm with > 90% drug entrapment efficiency. The 5-NPPP polymeric nanoparticles loaded PVA hydrogels were fabricated to provide a predetermined sustained release of the compound to provide a synergistic effect. The selected 7% PVA hydrogels loaded with the dual drugs were evaluated using Balb/c mice models induced with S. aureus soft skin infections. The results of in vivo studies were evidence that the dual drugs loaded hydrogels were non-toxic and reduced the bacterial load causing re-sensitization towards antibiotics, which could initiate re-epithelization. The research concluded that the PVA hydrogels loaded with CIP and 5-NPPP nanoparticles could be an ideal and promising drug delivery system for treating S. aureus-induced skin infections.

Carboxymethyl cellulose@multi wall carbon nanotubes functionalized with Ugi reaction as a new curcumin carrier

In recent years, the fabrication of new drug delivery systems (DDSs) based on functionalization by multi-component reactions (MCRs) has received special attention. In this regard, to obtain a new oral administration system for colon-specific cancer treatment, the CMC@MWCNTs@FCA carrier was designed and prepared from the functionalization of the CMC@MWCNTs as a biocompatible raw material with carboxamide group by the Ugi reaction. FT-IR analysis confirmed the successful synthesis of the product through the change in the functional groups of reagents. Additionally, the crystalline structure and porosity of the samples were studied by XRD and BET techniques. After a detailed characterization, the curcumin (CUR) was loaded on CMC@MWCNTs and CMC@MWCNTs@FCA, respectively, about 29 % and 38 %. In vitro drug release behavior studies for CUR-loaded CMC@MWCNTs@FCA showed the controlled release for it, so 11.6 % and 76.5 % of CUR, respectively were released at pH 1.2 and pH 7.4. Toxicological analysis displayed the IC₅₀ of CMC@MWCNTs@FCA@CUR is 752 μg/mL. In conclusion, the obtained findings display that the fabricated system can be proposed as a biocompatible carrier for specific colon cancer treatment.

Delivery of curcumin in a carboxymethyl cellulose and hydroxypropyl methyl cellulose carrier: Physicochemical properties and biological activity

Curcumin solid dispersions (Cur SDs) were prepared using hydroxypropyl methyl cellulose (HPMC) and sodium carboxymethyl cellulose (CMC) at different dosages. The results of Fourier transform infrared spectroscopy and Raman spectroscopy showed that the characteristic peak of curcumin shifted, and the addition of CMC enhanced this phenomenon. The addition of CMC reduced the contact angle, increased the surface free energy, and improved the solubility of Cur SDs. These changes were positively correlated with the amount of CMC. The surface morphology of Cur SDs changed from needle-like to sheet-like as observed by scanning electron microscopy. Cur SDs prepared by CMC and HPMC retained good biological activity. HT-29 human colon cancer cell analysis showed that the addition of CMC significantly improved the anti-proliferation effect of Cur SDs, thus enhancing the bioavailability of curcumin. Solid dispersions made with CMC and HPMC will be a promising hydrocolloid carrier to improve oral bioavailability and efficacy of curcumin.

A Double-Layer Hydrogel Dressing with High Mechanical Strength and Water Resistance Used for Drug Delivery

Hydrogel dressings provide a moist wound healing environment, absorb the exudates of the wound, and have better biocompatibility than traditional dressings. However, it is still difficult to meet the needs of modern medicine due to the defects in drug burst release, weak mechanical strength, and poor water retention. To solve these problems, we developed a double-layer (DL) hydrogel based on β-cyclodextrin polymer (β-CDP), poly(vinyl alcohol) (PVA), and carboxymethyl cellulose sodium (CMC) via a layer-by-layer method. Inspired by natural coconut, this hydrogel consisted of a drug release layer (DRL) and a mechanical support layer (MSL). In our design, the introduction of β-CDP into the DRL slowed the drug release rate of the DL hydrogel. Furthermore, the mechanical strength of the hydrogel was improved by immersing the MSL in a calcium chloride/boric acid solution. Combining these two layers, the tensile strength and elongation at break of the DL hydrogel reached 1504 kPa and 400%, respectively. More interestingly, the release mechanism of DL hydrogel conformed to the diffusion-relaxation-erosion model, which was different from traditional hydrogel dressings. Therefore, the as-prepared DL structure represents a feasible solution for fabricating high-performance mechanical hydrogel dressings with sustained drug release properties, and the DL hydrogel has potential to be used for medical dressings applied in daily life.

Chitosan-based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS-based nanoparticles (CS-NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS-NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P-glycoprotein (P-gp) to reverse drug resistance. These nanoarchitectures can provide co-delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co-loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid-, carbon-, polymeric- and metal-based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS-NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS-NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH-sensitive release of DOX can occur. Furthermore, redox- and light-responsive CS-NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS-NPs, we expect to soon see significant progress towards clinical translation.

Preparation and Synergistic Effect of Biomimetic Poly(lactic acid)/Graphene Oxide Composite Scaffolds Loaded with Dual Drugs

To promote the bone repair ability of drug-loaded scaffolds, poly(lactic acid) (PLA)/graphene oxide (GO)/Salvianolic acid B (Sal-B)/aspirin (ASA) dual drug-loaded biomimetic composite scaffolds were prepared. The results showed that the addition of these two drugs delayed the gel formation of the composite system, but a biomimetic nanofiber structure could still be obtained by extending the gel time. The addition of Sal-B increased the hydrophilicity of the scaffold, while an increase in ASA reduced the porosity. Dual drug-loaded scaffolds had good haemocompatibility and synergically promoted the proliferation of MC3T3-E1 cells and enhanced alkaline phosphatase activity. Sustained-release experiments of the two drugs showed that the presence of ASA slowed the cumulative release of Sal-B, while Sal-B promoted the release of ASA. Kinetic modeling showed that the release of both drugs conforms to the Korsmeyer-Peppas model, but Sal-B conforms to the Fick diffusion mechanism and ASA follows Fick diffusion and carrier swelling/dissolution.

Impact of pulping routes of rice straw on cellulose nanoarchitectonics and their behavior toward Indigo dye

This work deals with emphasizing the relation between particle dimension distribution of nanocellulose (PDD) particles with its efficiency as stabilizing/adsorbent agent of Indigo dye. In this respect, different pulping reagents were used in preparation of Rice straw pulps as precursors for nanocelluloses using acid hydrolysis and oxidizing agents [(KMnO4 and NH4)2S2O8] methods. The PDD was estimated by indirect method through processing the TEM images using the software ImageJ. The resulting nanocelluloses were also characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR) together with sulfate ester and carboxyl contents. The data showed the effective role of pulping reagent on PDD. The cellulose nanocrystals (CNCs) from NaOH-AQ pulp, with the longest crystal length (204.4 ± 107.8 nm) and the lowest diameter (6.7 ± 2.3 nm), exhibited most stabilized suspension of dye; however, the highest adsorption capacity was accompanied the oxidized nanocellulose (Ox-NC) from neutral RS pulp with lowest PDD (4.98 ± 1.6 and 90.5 ± 3.14), together with highest COO content (476.46 μmol/g).

Unravelling the role of hemp straw derived cellulose in CMC/PVA hydrogel for sustained release of fluoroquinolone antibiotic

Cellulose fibres derived from hemp stalks, a prevalent biowaste in Northern India, were effectively converted into carboxymethyl cellulose (HS-CMC). Novel environmentally benign hydrogels were synthesized from HS-CMC and polyvinyl alcohol (PVA) using citric acid, a green crosslinker employing freeze-drying method. The HS-CMC/PVA hydrogels were successfully used for sustained release of fluoroquinolone antibiotic, norfloxacin. The hydrogels were characterized using FTIR, XRD, FE-SEM, EDS and thermal stability and evaluated for their carbonyl content, swelling ratio, in-vitro drug release behaviour and bactericidal properties. Successful isolation of cellulose from hemp stalks and its conversion into hydrogel with the presence of ester and carbonyl linkages was confirmed by FTIR. Thermal stability was impaired when cellulose fibres were converted into HS-CMC via carboxymethylation, as the crystalline structure was utterly disrupted. For the hydrogel, the equilibrium swelling ratios at pH -1.2 and 7.4 were assessed as 378.4 % and 538.7 %, respectively, higher than reported CMC hydrogels. The norfloxacin (NFX) encapsulated hydrogels exhibited good bactericidal properties with zone of inhibition of 19.2 ± 0.3 mm against E. coli and 16.4 ± 0.4 mm against S. aureus. The in-vitro release of NFX at pH 1.2 was 91 %, higher than pH 7.4 at 82 % with strong adherence to Higuchi kinetics model signifying that the release of NFX is via dissolution and diffusion. The release kinetics at different pH revealed Fickian behaviour establishing the potential of HS-CMC hydrogel for sustained release of norfloxacin.

Cellulosic Polymers for Enhancing Drug Bioavailability in Ocular Drug Delivery Systems

One of the major impediments to drug development is low aqueous solubility and thus poor bioavailability, which leads to insufficient clinical utility. Around 70–80% of drugs in the discovery pipeline are suffering from poor aqueous solubility and poor bioavailability, which is a major challenge when one has to develop an ocular drug delivery system. The outer lipid layer, pre-corneal, dynamic, and static ocular barriers limit drug availability to the targeted ocular tissues. Biopharmaceutical Classification System (BCS) class II drugs with adequate permeability and limited or no aqueous solubility have been extensively studied for various polymer-based solubility enhancement approaches. The hydrophilic nature of cellulosic polymers and their tunable properties make them the polymers of choice in various solubility-enhancement techniques. This review focuses on various cellulose derivatives, specifically, their role, current status and novel modified cellulosic polymers for enhancing the bioavailability of BCS class II drugs in ocular drug delivery systems.

Redox- and Enzyme-Responsive Macrospheres Gatekept by Polysaccharides for Controlled Release of Agrochemicals

Stimuli-responsive materials afford researchers an opportunity to synthesize controlled-release carriers with various potential applications, especially for reducing the abuse of chemical reagents in farmland soil. To enhance the efficiency of agrochemical utilization, redox- and enzyme-responsive macrospheres were prepared by self-assembling β-cyclodextrin-modified zeolite and ferrocenecarboxylic acid (FcA)-grafted carboxymethyl cellulose (CMC). Scanning electron microscopy and Brunauer-Emmett-Teller analysis revealed that pores of zeolite were sealed by the surface coupling of FcA-modified CMC via the formation of an inclusion complex. Salicylic acid (SA) was loaded as a model agrochemical. The release of SA from macrospheres could be triggered in the presence of hydrogen peroxide (oxidant) and cellulase (enzyme); and the corresponding release percentages, 85.2 and 80.4%, were much higher than those of the control sample without responsive groups in water (12.6%) after 12 h. A release kinetic study showed that cellulase could promote carrier dissolution more effectively than the oxidant. The results demonstrate that the dual-responsive macrospheres are promising as a smart and effective carrier for the controlled release of agrochemicals.

Spray-drying encapsulation of microwave-assisted extracted polyphenols from Moringa oleifera: Influence of tragacanth, locust bean, and carboxymethyl-cellulose formulations

In this work, polyphenols from Moringa oleifera (Mor) leaves were extracted by microwave-assisted extraction (MAE) and encapsulated by spray-drying (SD). Particularly, we explored the influence of tragacanth gum (TG), locust bean gum (LBG), and carboxymethyl-cellulose (CMC) as wall-materials on the physicochemical behavior of encapsulated Mor. Single or combined wall-material treatments (100:00 and 50:50 ratios, and total solid content 1%) were tested. The results showed the wall-material had a significant effect on the process yield (55.7-68.3%), encapsulation efficiency (24.28-35.74%), color (yellow or pale-yellow), total phenolic content (25.17-27.49 mg GAE g^-1 of particles), total flavonoid content (23.20-26.87 mg QE g^-1 of particles), antioxidant activity (DPPH^• = 5.96-6.95 mg GAE g^-1; ABTS^•+ = 5.61-6.18 mg TE g^-1 of particles), and particle size distribution (D₅₀ = 112-1946 nm) of the encapsulated Mor. On the other hand, SEM analysis showed smooth and spherical particles, while TGA and DSC analyses confirmed the encapsulation of bioactive compounds based on the changes in thermal peaks. Finally, XRD analysis showed that the particles have an amorphous behavior. The encapsulated Mor produced with individual TG or CMC demonstrated better properties than those obtained from mixed gums. Thus, TG or CMC might be feasible wall materials for manufacturing encapsulated Mor that conserve the phenolic content and antioxidant activity.

Construction of Surface-Modified Polydopamine Nanoparticles for Sequential Drug Release and Combined Chemo-Photothermal Cancer Therapy

Single chemotherapy often causes severe adverse effects and drug resistance to limit therapeutic efficacy. As a noninvasive approach, photothermal therapy (PTT) represents an attractive option for cancer therapy due to the benefits of remote control and precise treatment methods. Nanomedicines constructed with combined chemo-photothermal properties may exert synergistic effects and improved antitumor efficacy. In this study, we developed polydopamine (PDA)-coated nanoparticles grafted with folic acid (FA) and polyethylene glycol to transport doxorubicin (DOX) for targeted cancer therapy. The results showed that this delivery vehicle has a nanoscale particle size and narrow size distribution. No particle aggregation or significant drug leakage was observed during the stability test. This system presented excellent photothermal conversion capability under near-infrared light (NIR) laser irradiation due to the PDA layer covering. In vitro dissolution profiles demonstrated that sequential and triggered DOX release from nanoparticles was pH-, NIR irradiation-, and redox level-dependent and could be best fitted with the Ritger-Peppas equation. FA modification effectively promoted the intracellular uptake of nanoparticles by HepG2 cells and therefore significantly inhibited cell recovery and induced tumor cell apoptosis. Compared to the free DOX group, nanoparticles reduced the DOX concentration in the heart to avoid drug-related cardiotoxicity. More importantly, the in vivo antitumor efficacy results showed that compared with the single chemotherapy strategy, the nanoparticle group exerted combined and satisfactory tumor growth inhibition effects with good biocompatibility. In summary, this nanocarrier delivery system can organically combine chemotherapy and PTT to achieve effective and precise cancer treatment.