Polyelectrolyte complex of carboxymethyl gum katira-chitosan: Preparation and characterization

Biofilm hydrogel derived from physical crosslinking (self-assembly) of xanthan gum and chitosan for removing Cd2+, Ni2+, and Cu2+ from aqueous solution

This study aimed to fabricate a series of biodegradable hydrogel films by gelating/physically crosslinking a blend of xanthan gum (XG) and chitosan (CS) in various combinations using a facile, green, and low cost solution casting technique. The adsorption of Cd2+, Cu2+ and Ni2+ by the XG/CS biofilm in aqueous solution was studied in batch experiments to determine how the pH of the solution, contact time, dosage of adsorbent, initial metal ion concentration and ionic strength affect its adsorption. A highly pH-dependent adsorption process was observed for three metal ions. A maximum amount of Cd2+, Ni2+, and Cu2+ ions was adsorbable with 50 mg of the adsorbent at pH 6.0 for an initial metal concentration of 50 mg.L-1. An empirical pseudo-second-order model seems to fit the kinetic experimental data reasonably well. It was found that the Langmuir model correlated better with equilibrium isotherm when compared with the Freundlich model. For Cd2+, Ni2+, and Cu2+ ions at 25 °C, the maximum monolayer adsorption capacity was 152.33, 144.79, and 139.71 mg.g-1, respectively. Furthermore, the biofilm was capable of regenerating, allowing metal ions to adsorb and desorb for five consecutive cycles. Therefore, the developed biodegradable film offers the potential for remediation of specified metal ions.

Preparation and characterization of peach gum/chitosan polyelectrolyte composite films with dual cross-linking networks for antibacterial packaging

Peach gum (PG) is a valuable polymeric feedstock for developing eco-friendly, bio-safe, and functional materials. However, PG has limited use in food packaging due to its inferior mechanical and antibacterial properties. To overcome these limitations, we created a dual cross-linked network by introducing chitosan (CS) and glycerol to the PG matrix. Our research discovered that incorporating CS into the PG matrix significantly improved its Young's modulus, from 277.62 to 925.89 MPa, and its tensile strength from 5.96 to 39.94 MPa. Furthermore, the inclusion of glycerol greatly increased the elongation. These enhancements were attributed to the ionic and hydrogen-bonding interactions between the two biopolymers. Additionally, the composite films exhibited strong antibacterial effects, reducing the total number of colonies by 99.2 % and 99.9 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. The incorporation of CS resulted in more amorphous films, enhancing their stiffness, flexibility, and barrier properties. To assess the practical application of PG/CS composite films, we conducted a comparative analysis between non-packaged strawberries and strawberries packaged with these films. The results demonstrated that the composite polyelectrolyte film extended the shelf life of strawberries better than the non-packaged fruits.

Carboxymethylated Gums and Derivatization: Strategies and Significance in Drug Delivery and Tissue Engineering

Natural polysaccharides have been widely exploited in drug delivery and tissue engineering research. They exhibit excellent biocompatibility and fewer adverse effects; however, it is challenging to assess their bioactivities to that of manufactured synthetics because of their intrinsic physicochemical characteristics. Studies showed that the carboxymethylation of polysaccharides considerably increases the aqueous solubility and bioactivities of inherent polysaccharides and offers structural diversity, but it also has some limitations that can be resolved by derivatization or the grafting of carboxymethylated gums. The swelling ratio, flocculation capacity, viscosity, partition coefficient, metal absorption properties, and thermosensitivity of natural polysaccharides have been improved as a result of these changes. In order to create better and functionally enhanced polysaccharides, researchers have modified the structures and properties of carboxymethylated gums. This review summarizes the various ways of modifying carboxymethylated gums, explores the impact that molecular modifications have on their physicochemical characteristics and bioactivities, and sheds light on various applications for the derivatives of carboxymethylated polysaccharides.

Films composed of white angico gum and chitosan containing chlorhexidine as an antimicrobial agent

Anadenanthera colubrina, popularly known as white angico, is a species extensively cultivated in Brazil, mainly in the cerrado region, including the state of Piauí. This study examines the development of films composed of white angico gum (WAG) and chitosan (CHI) and containing chlorhexidine (CHX), an antimicrobial agent. The solvent casting method was used to prepare films. Different combinations and concentrations of WAG and CHI were used to obtain films with good physicochemical characteristics. Properties such as the in vitro swelling ratio, the disintegration time, folding endurance, and the drug content were determined. The selected formulations were characterised by scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction, and the CHX release time and antimicrobial activity were evaluated. CHX showed a homogenous distribution in all CHI/WAG film formulations. The optimised films showed good physicochemical properties with 80% CHX release over 26 h, which is considered promising for local treatment of severe lesions in the mouth. Cytotoxicity tests of the films did not show toxicity. The antimicrobial and antifungal effects were very effective against the tested microorganisms.

Recent Advances and Prospects for Plant Gum-Based Drug Delivery Systems: A Comprehensive Review

This work is an effort to first introduce plant-based gums and discussing their drug delivery applications. The composition of these plant gums and their major characteristics, which make them suitable as pharmaceutical excipients are also described in detail. The various modifications methods such as physical and chemical modifications of gums and polysaccharides have been discussed along with their applications in different fields. Consequently, plant-based gums modification such as etherification and grafting is attracting much scientific attention to satisfy industrial demand. The evaluation tests to characterize gum-based drug delivery systems have been summarized. The release behavior of drug from plant-gum-based drug delivery is being discussed. Thus, this review is an attempt to critically summarize different aspect of plant-gum-based polysaccharides to be utilized in drug delivery systems having potential industrial applications.

Recent Progress on Modified Gum Katira Polysaccharides and Their Various Potential Applications

Gum katira polysaccharide is biocompatible and non-toxic, and has antioxidant, anti-microbial, and immunomodulatory properties. It is a natural polysaccharide and exudate derived from the stem bark of Cochlospermum reliogosum Linn. Additionally, it has many traditional medicinal uses as a sedative and for the treatment of jaundice, gonorrhea, syphilis, and stomach ailments. This article provides an overview of gum katira, including its extraction, separation, purification, and physiochemical properties and details of its characterization and pharmacognostic features. This paper takes an in-depth look at the synthetic methods used to modify gum katira, such as carboxymethylation and grafting triggered by free radicals. Furthermore, this review provides an overview of its industrial and phytopharmacological applications for drug delivery and heavy metal and dye removal, its biological activities, its use in food, and the potential use of gum katira derivatives and their industrial applications. We believe researchers will find this paper useful for developing techniques to modify gum katira polysaccharides to meet future demands.

Chitosan/Sodium Dodecyl Sulfate Complexes for Microencapsulation of Vitamin E and Its Release Profile-Understanding the Effect of Anionic Surfactant

Microencapsulation of bioactive substances is a common strategy for their protection and release rate control. The use of chitosan (Ch) is particularly promising due to its abundance, biocompatibility, and interaction with anionic surfactants to form complexes of different characteristics with relevance for use in microcapsule wall design. In this study, Ch/sodium dodecyl sulfate (SDS) microcapsules, without and with cross-linking agent (formaldehyde (FA) or glutaraldehyde (GA)), were obtained by the spray drying of vitamin E loaded oil-in-water emulsion. All of the microcapsules had good stability during the drying process. Depending on the composition, their product yield, moisture content, and encapsulation efficiency varied between 11-34%, 1.14-1.62%, and 94-126%, respectively. SEM and FTIR analysis results indicate that SDS as well as cross-linkers significantly affected the microcapsule wall properties. The profiles of in vitro vitamin E release from the investigated microcapsules fit with the Korsmeyer-Peppas model (r² > 0.9). The chemical structure of the anionic surfactant was found to have a significant effect on the vitamin E release mechanism. Ch/SDS coacervates may build a microcapsule wall without toxic crosslinkers. This enabled the combined diffusion/swelling based release mechanism of the encapsulated lipophilic substance, which can be considered favorable for utilization in food and pharmaceutical products.

Quality by Design tools reducing the gap from bench to bedside for nanomedicine

Pharmaceutical nanotechnology research is focused on smart nano-vehicles, which can deliver active pharmaceutical ingredients to enhance their efficacy through any route of administration and in the most varied therapeutical application. The design and development of new nanopharmaceuticals can be very laborious. In recent years, the application of mathematics, statistics and computational tools is emerging as a convenient strategy for this purpose. The application of Quality by Design (QbD) tools has been introduced to guarantee quality for pharmaceutical products and improve translational research from the laboratory bench into applicable therapeutics. In this review, a collection of basic-concept, historical overview and application of QbD in nanomedicine are discussed. A specific focus has been put on Response Surface Methodology and Artificial Neural Network approaches in general terms and their application in the development of nanomedicine to monitor the process parameters obtaining optimized system ensuring its quality profile.

A Review of Gum Hydrocolloid Polyelectrolyte Complexes (PEC) for Biomedical Applications: Their Properties and Drug Delivery Studies

The utilization of natural gum polysaccharides as the vehicle for drug delivery systems and other biomedical applications has increased in recent decades. Their biocompatibility, biodegradability, and price are much cheaper than other materials. It is also renewable and available in massive amounts, which are the main reasons for its use in pharmaceutical applications. Gum can be easily functionalized with other natural polymers to enhance their applications. Various aspects of the utilization of natural gums in the forms of polyelectrolyte complexes (PECs) for drug delivery systems are discussed in this review. The application of different mathematical models were used to represent the drug release mechanisms from PECs; these models include a zero-order equation, first-order equation, Higuchi, simplified Higuchi, Korsmeyer–Peppas, and Peppas–Sahlin.

Methacrylated Gellan Gum/Poly-l-lysine Polyelectrolyte Complex Beads for Cell-Based Therapies

Cell encapsulation strategies using hydrogel beads have been considered as an alternative to immunosuppression in cell-based therapies. They rely on layer-by-layer (LbL) deposition of polymers to tune beads' permeability, creating a physical barrier to the host immune system. However, the LbL approach can also create diffusion barriers, hampering the flow of essential nutrients and therapeutic cell products. In this work, the polyelectrolyte complex (PEC) methodology was used to circumvent the drawbacks of the LbL strategy by inducing hydrogel bead formation through the interaction of anionic methacrylated gellan gum (GG-MA) with cationic poly-l-lysine (PLL). The interfacial complexation between both polymers resulted in beads with a cell-friendly GG-MA hydrogel core surrounded by a PEC semipermeable membrane. The beads showed great in vitro stability over time, a semi-permeable behavior, and supported human adipose-derived stem cell encapsulation. Additionally, and regarding immune recognition, the in vitro and in vivo studies pointed out that the hydrogel beads behave as an immunocompatible system. Overall, the engineered beads showed great potential for hydrogel-mediated cell therapies, when immunoprotection is required, as when treating different metabolic disorders.

Study of Different Chitosan/Sodium Carboxymethyl Cellulose Proportions in the Development of Polyelectrolyte Complexes for the Sustained Release of Clarithromycin from Matrix Tablets

This study investigated the combination of different proportions of cationic chitosan and anionic carboxymethyl cellulose (CMC) for the development of polyelectrolyte complexes to be used as a carrier in a sustained-release system. Analysis via scanning electron microscopy (SEM) Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) confirmed ionic interactions occur between the chitosan and carboxymethyl cellulose chains, which increases drug entrapment. The results of the dissolution study in acetate buffer (pH 4.2) showed significant increases in the kinetic profiles of clarithromycin for low proportions of chitosan/carboxymethyl cellulose tablets, while the tablets containing only chitosan had high relaxation of chitosan chains and disintegrated rapidly. The Korsmeyer–Peppas kinetic model for the different interpolymer complexes demonstrated that the clarithromycin transport mechanism was controlled by Fickian diffusion. These results suggest that the matrix tablets with different proportions of chitosan/carboxymethyl cellulose enhanced the ionic interaction and enabled the prolonged release of clarithromycin.

Naturally Occurring Polyelectrolytes and Their Use for the Development of Complex-Based Mucoadhesive Drug Delivery Systems: An Overview

Biopolymers have several advantages for the development of drug delivery systems, since they are biocompatible, biodegradable and easy to obtain from renewable resources. However, their most notable advantage may be their ability to adhere to biological tissues. Many of these biopolymers have ionized forms, known as polyelectrolytes. When combined, polyelectrolytes with opposite charges spontaneously form polyelectrolyte complexes or multilayers, which have great functional versatility. Although only one natural polycation-chitosan has been widely explored until now, it has been combined with many natural polyanions such as pectin, alginate and xanthan gum, among others. These polyelectrolyte complexes have been used to develop multiple mucoadhesive dosage forms such as hydrogels, tablets, microparticles, and films, which have demonstrated extraordinary potential to administer drugs by the ocular, nasal, buccal, oral, and vaginal routes, improving both local and systemic treatments. The advantages observed for these formulations include the increased bioavailability or residence time of the formulation in the administration zone, and the avoidance of invasive administration routes, leading to greater therapeutic compliance.

Carboxymethyl cellulose-chitosan composite hydrogel: Modelling and experimental study of the effect of composition on microstructure and swelling response

Molecular recognition is essential for the advancement of functional supramolecular natural polymer-based hydrogels. First, a series of carboxymethyl cellulose (CMC)-chitosan (CSN) hydrogels crosslinked with fumaric acid are studied, where the influence of composition on microstructure and swelling is investigated using mathematical modelling and experiment and the hydrolytic properties, microstructure parameters and physicochemical properties are examined. Second, best fit values for the responses are obtained using multiple linear regression and MATLAB R2020a curve fitting and predictive models are generated. Third, the optimum microstructure is loaded with polyethylene glycol (PEG) and bismuth telluride (Bi₂Te₃) and coated on fabric for imparting thermal sensitivity. The results show that (1) optimum microstructure (25.65 ± 1.86 nm mesh size, 116.25 ± 0.00 μmol/cm³ effective crosslinking-density, 348.03 ± 10.81% swelling, and 62.86 ± 1.11% gel fraction) is found at CMC:CSN = 1:3 for G3; (2) the model shows good agreement with experimental data demonstrating potential for estimating hydrogel swelling and microstructure; and (3) G3/PEG and G3/PEG/Bi₂Te₃ enhance thermal conductivity of fabric at ambient, body, and elevated temperatures. The study demonstrates the potential of the generated model in predicting CMC-CSN swelling and G3 as an ideal host matrix for wearable textiles/devices.

Study of vitamin E microencapsulation and controlled release from chitosan/sodium lauryl ether sulfate microcapsules

Potential benefit of microencapsulation is its ability to deliver and protect incorporated ingredients such as vitamin E. Microcapsule wall properties can be changed by adding of coss-linking agents that are usually considered toxic for application. The microcapsules were prepared by a spray-drying technique using coacervation method, by depositing the coacervate formed in the mixture of chitosan and sodium lauryl ether sulfate to the oil/water interface. All obtained microcapsules suspensions had slightly lower mean diameter compared to the starting emulsion (6.85 ± 0.213 μm), which shows their good stability during the drying process. The choice and absence of cross-linking agents had influence on kinetics of vitamin E release. Encapsulation efficiency of microcapsules without cross-linking agent was 73.17 ± 0.64 %. This study avoided the use of aldehydes as cross-linking agents and found that chitosan/SLES complex can be used as wall material for the microencapsulation of hydrophobic active molecules in cosmetic industry.

Effect of ibuprofen entrapment procedure on physicochemical and controlled drug release performances of chitosan/xanthan gum polyelectrolyte complexes

The effect of the entrapment procedure of a poorly water soluble drug (ibuprofen) on physicochemical and drug release performances of chitosan/xanthan polyelectrolyte complexes (PECs) was investigated to achieve controlled drug release as the ultimate goal. The formation of PECs for two drug entrapment procedures (before or after the mixing of polymers) at pH 4.6 and 5.6 and three chitosan-to-xanthan mass ratios (1:1, 1:2 and 1:3) was observed by continuous decrease in conductivity during the PECs formation and increased apparent viscosity and hysteresis values. The most extensive crosslinking was observed with ibuprofen added before the PECs formation at pH 4.6 and chitosan-to-xanthan mass ratio 1:1. The PECs prepared at polymers' mass ratios 1:2 and 1:3 had higher yield and drug entrapment efficiency. DSC and FT-IR analysis confirmed ibuprofen entrapment in PECs and the partial disruption of its crystallinity. All ibuprofen release profiles were similar, with 60-70% of drug released after 12 h, mainly by diffusion, but erosion and polymer chain relaxation were also included. Potentially optimal can be considered the PEC prepared at pH 4.6, ibuprofen entrapped before the mixing of polymers at chitosan-to-xanthan mass ratio 1:2, which provided controlled drug release by zero-order kinetics, high yield, and drug entrapment efficiency.

Antibacterial nanobiocomposite based on halloysite nanotubes and extracted xylan from bagasse pith

In this study, the antibacterial polyelectrolyte carboxymethyl xylan/chitosan (CMX/CS) films incorporated with halloysite nanotubes (HNTs) and Origanum vulgare essential oil (OEO) were prepared and then characterized. Xylan-rich hemicelluloses (62.23%) were extracted from sugarcane bagasse pith and then subjected to carboxymethylation. FTIR analysis revealed the successful modification of hemicelluloses. The irregular white spots in SEM images of nanobiocomposites revealed the entrance of HNTs into the polymer matrix. EDX maps manifested that the density of Si and Al atoms increased, as the amount of HNT increased. The observed discontinuities for EO-containing nanobiocomposites in the SEM images may be attributed to the hydrophobic nature of EO. The barrier properties of the nanocomposites improved by incorporation of HNTs and O. vulgare. The tensile strength of nanocomposite improved significantly by incorporating HNT. EO/HNT-containing films exhibited a higher antibacterial activity against selected bacteria than HNT-containing films.

Anthelmintic activity of nanoencapsulated carvacryl acetate against gastrointestinal nematodes of sheep and its toxicity in rodents

The objective of this study was to evaluate the efficacy of carvacryl acetate (CVA) and nanoencapsulated CVA (nCVA) on gastrointestinal nematodes of sheep. The CVA was nanoencapsulated with chitosan/gum arabic and the efficacy of nanoencapsulation (EE), yield, zeta potential, nanoparticle morphology and release kinetics at pH 3 and 8 were analyzed. Acute and subchronic toxicity were evaluated in rodents and reduction of egg counts in the faeces (FECRT) of sheep. The sheep were divided into four groups (n = 10): G1, 250 mg/kg CVA; G2, 250 mg/kg nCVA; G3, polymer matrix and G4: 2.5 mg/kg monepantel. EE and nCVA yield were 65% and 57%, respectively. The morphology of the nanoparticles was spherical, size (810.6±286.7 nm), zeta potential in pH 3.2 (+18.3 mV) and the 50% release of CVA at pHs 3 and 8 occurred at 200 and 10 h, respectively. nCVA showed LD50 of 2,609 mg/kg. CVA, nCVA and monepantel reduced the number of eggs per gram of faeces (epg) by 57.7%, 51.1% and 97.7%, respectively. The epg of sheep treated with CVA and nCVA did not differ from the negative control (P>0.05). Nanoencapsulation reduced the toxicity of CVA; however, nCVA and CVA presented similar results in the FECRT.

Optimization of ZnAl/Chitosan Supra-Nano Hybrid Preparation as Efficient Antibacterial Material

The menace of antimicrobial resistance continues to increase and hence the need to discover new antibiotics, especially alternative and effective sources such as hybrid organic-inorganic, organic-organic materials, and other combinations. In this study, an antimicrobial hybrid supra-nano material was prepared by the bi-titration synthesis method of chitosan (CS) and ZnAl layered double hydroxide. Fourier-transform infrared spectrometer (FTIR), thermogravimetric and differential thermal gravimetric (TGA/DTG), ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses indicated that the ZnAl/CS hybrid exhibited low crystallinity with high thermal stability. The results of ZnAl/CS characterization showed the characteristic properties of the individual components ZnAl and CS, indicating a successful preparation of the ZnAl/CS hybrid. The antibacterial tests revealed that the ZnAl/CS hybrid possessed an enhanced antimicrobial effect against both Escherichia coli (E. coli, MTCC 739) and Penicilliumcyclopium (P. cyclopium, AS 3.4513). Under the central composite design (CCD) of the response surface methodology (RSM) tool, the parameters of the hybrid synthesis reaction were optimized and the result obtained was as follows: reaction pH was 11.3, reagent Zn/Al ratio was 3.27, and chitosan concentration was 1.07 g/L. After optimization, it was found that the antibacterial activity of ZnAl/CS was strengthened against E. coli as evidenced by a widening of the inhibition zone of about 41.6%. The antibacterial activity of ZnAl/CS was mainly due to the reactivation of the antibacterial activity of CS associated with the release of Zn²⁺ and Al³⁺ metal ions in addition to ZnO, Al₂O₃, and ZnAl₂O₄ compounds resulting from the method of preparation.