Tailored-interpenetrating polymer network beads of κ-carrageenan and sodium carboxymethyl cellulose for controlled drug delivery

Exploring carrageenan: From seaweed to biomedicine-A comprehensive review

Biomaterials are pivotal in the realms of tissue engineering, regenerative medicine, and drug delivery and serve as fundamental building blocks. Within this dynamic landscape, polymeric biomaterials emerge as the frontrunners, offering unparalleled versatility across physical, chemical, and biological domains. Natural polymers, in particular, captivate attention for their inherent bioactivity. Among these, carrageenan (CRG), extracted from red seaweeds, stands out as a naturally occurring polysaccharide with immense potential in various biomedical applications. CRG boasts a unique array of properties, encompassing antiviral, antibacterial, immunomodulatory, antihyperlipidemic, antioxidant, and antitumor attributes, positioning it as an attractive choice for cutting-edge research in drug delivery, wound healing, and tissue regeneration. This comprehensive review encapsulates the multifaceted properties of CRG, shedding light on the chemical modifications that it undergoes. Additionally, it spotlights pioneering research that harnesses the potential of CRG to craft scaffolds and drug delivery systems, offering high efficacy in the realms of tissue repair and disease intervention. In essence, this review celebrates the remarkable versatility of CRG and its transformative role in advancing biomedical solutions.

Carrageenan oligosaccharide alleviates intestinal damage via gut microflora through activating IMD/relish pathway in female Drosophila melanogaster

Recent evidence suggests the anti-inflammatory effect of carrageenan oligosaccharides (COS). The effects of COS on intestinal injury induced by 0.6% sodium dodecyl sulfate (SDS) and the molecular mechanisms involved were investigated in this study. 0.625, 1.25, and 2.5 mg/mL COS in diet had no toxic effect in flies, and they could all prolong SDS-treated female flies' survival rate. 1.25 mg/mL COS prevented the development of inflammation by improving the intestinal barrier integrity and maintaining the intestinal morphology stability, inhibited the proliferation of intestine stem cells (ISCs), and the production of lysosomes induced by SDS, accompanied by a decrease in the expression of autophagy-related genes. Moreover, COS decreased the active oxygen species (ROS) content in gut and increased the antioxidant activity in SDS-induced female flies, while COS still played a role in increasing survival rate and decreasing intestinal leakage in CncC-RNAi flies. The improvement of anti-inflammation capacity may be associated with the regulation of intestinal microflora with COS supplementation for Drosophila melanogaster. COS changed the gut microbiota composition, and COS had no effect on germ-free (GF) flies. It is highlighted that COS could not work in Relish-RNAi flies, indicating relish is required for COS to perform beneficial effects. These results provide insights into the study of gut microbiota interacting with COS to modulate intestinal inflammation in specific hosts.

Bioderived cellulose fibre-guar gum grafted poly (N, N'-dimethylacrylamide) polymer network for controlled release of metformin hydrochloride

An interpenetrating polymer network (IPN) of areca cellulose and guar gum grafted with poly (N, N'-dimethylacrylamide) was made by microwave irradiation technique. N, N-methylenebisacrylamide (MBA) was used as the crosslinking agent. The network polymer was characterised using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Powder X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The chemical interaction between the drug and the polymer was studied using Differential Scanning Calorimetry (DSC). The swelling of the gel was measured under different pH conditions and the swelling parameters were evaluated. The gel was loaded with an anti-diabetic drug, Metformin Hydrochloride, and the in vitro drug release was studied in gastric and intestinal conditions. The results indicated complete release of the drug in 6 h under pH 1.2 and in 10 h under pH 7.4. The kinetic analysis of release data indicated the drug release to follow Higuchi's model. The release exponent "n" of Korsmeyer-Peppas model was found to be >0.45 indicating the drug diffusion to be a non-Fickian process.

Preparation and in vitro/in vivo characterization of sustained-release ciprofloxacin-carrageenan complex

The goal of the study was to look into drug-polyelectrolyte complexation between ciprofloxacin (Cipro) and λ-carrageenan (CRG), and to employ the complex as a sustained-release matrix. The maximum binding capacity of the complexation was determined using the dialysis bag method and employed to prepare the complex. In comparison to Cipro, CRG, and their physical mixing, the complex was examined using differential scanning calorimetry, Fourier infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopy. Cipro-CRG matrices, manufactured as direct compression tablets based on the greatest binding capacity, were assessed for swelling, erosion and drug release in 0.1 M HCl, in comparison with those of CRG, Hydroxypropyl methylcellulose (HPMC) and Cipro-HPMC matrices. In vivo absorption study comparing the Cipro-CRG matrix to Cipro immediate-release tablet was also carried out. The greatest binding capacity of Cipro to CRG was 55% (w/w). Multiple interactions, including electrostatic interaction, Vander wall forces, and hydrogen bonding, have been proposed to be involved in complexation with drug amorphization. As a result of the complexation, the swelling and erosion properties of CRG changed, with Cipro-CRG matrix showing substantially less swelling and erosion than Cipro-free CRG matrix. Cipro-CRG matrix exhibited swelling and erosion similar to Cipro-HPMC matrix. However, the former matrix demonstrated Cipro release with significantly less burst impact and a significantly slower release rate. Furthermore, Cipro-CRG matrices in vivo demonstrated slow-prolonged oral drug absorption with consequent significant changes in pharmacokinetic parameters in comparison to those obtained for immediate-release tablets.

Development and characterization of crosslinked k-carrageenan/sericin blend with covalent agents or thermal crosslink for indomethacin extended release

Modified release of multiparticulate pharmaceutical forms is a key therapeutic strategy to reduce side effects and toxicity caused by high and repeated doses of immediate-release oral drugs. This research focused on the encapsulation of indomethacin (IND) in the crosslinked k-Car/Ser polymeric matrix by covalent and thermal methods to evaluate drug delivery modulation and properties of the crosslinked blend. Therefore, the entrapment efficiency (EE %), drug loading (DL %) and physicochemical properties of the particles were investigated. The particles presented a spherical shape and a rough surface with a mean diameter of 1.38-2.15 mm (CCA) and 1.56-1.86 mm (thermal crosslink). FTIR investigation indicated the presence of IDM in the particles and X-ray pattern showed the maintenance of crystallinity of IDM. The in vitro release in acidic medium (pH 1.2) and phosphate buffer saline solution (pH 6.8) was 1.23-6.81 % and 81-100 %, respectively. Considering the results, the formulations remained stable after 6 months. The Weibull equation was adequately fitted for all formulations and a diffusion mechanism, swelling and relaxation of chain were observed. IDM-loaded k-carrageenan/sericin/CMC increases cell viability (> 75 % for neutral red and > 81 % for MTT). Finally, all formulations present gastro-resistance, pH response and altered release and have the potential to be used as drug delivery careers.

k-Carrageenan/sericin-based multiparticulate systems: A novel gastro-resistant polymer matrix for indomethacin delivery

This study aimed to develop a natural and multiparticulate carrier of k-carrageenan (k-Car) and sericin (Ser) for encapsulation of indomethacin (IND) in order to minimize gastrointestinal effects caused by immediate-release. Increasing the amount of IND in the formulations subtly reduced the entrapment efficiency (EE) and drug loading (DL) due to matrix saturation. Sericin was essential to improve EE and DL when compared to pure k-Car (EE > 90 % and DL > 47 %) with suitable particle sizes (1.3461 ± 0.1891-1.7213 ± 0.1586 mm). The incorporation and integrity of IND in the particles were confirmed by analytical techniques of HPLC, XRD, FTIR, and SEM. Additionally, the k-Car/Ser matrix was pH-responsive with low IND release at pH 1.2 and extended-release at pH 6.8. The Weibull model had an adequate fit to the experimental data with R²aju 0.950.99 and AIC 82.4-24.9, with curves in parabolic profile (b < 1) and indicative of a controlled drug-release mechanism by diffusion. Besides, k-Car/Ser/IND and placebo were not cytotoxic (cell viability > 85 % at 150-600 μM) for the Caco-2 cell line. Therefore, the polymeric matrix is gastro-resistant, stable, and biocompatible to carry indomethacin and deliver it to the intestinal environment.

Development of soy protein isolate/sodium carboxymethyl cellulose synbiotic microgels by double crosslinking with transglutaminase and aluminum chloride for delivery system of Lactobacillus acidophilus

This study was carried out to develop soy protein isolate (SPI)/sodium carboxymethyl cellulose (NaCMC) synbiotic microgels by applying a double-crosslinking technique using transglutaminase and different concentrations of AlCl₃ (0, 6, 7, 8 %) and also by adding Lactobacillus acidophilus (L. acidophilus) and pectic oligosaccharide. Synbiotic microgels crosslinked using 8 % AlCl₃ (SPI/NaCMC-Al³⁺₈ microgels) showed the highest encapsulation efficiency (92 %). The double-crosslinked microgels exhibited a smooth surface as proved by SEM. FT-IR, XRD, and DSC analyses showed the possible interaction within matrices and demonstrated the higher thermal stability of synbiotic microgels prepared using a higher concentration of AlCl₃. All in all, after exposure to simulated digestion fluid, heat treatment (72 °C, 15 s), and refrigerated storage, more cells in double-crosslinked microgels survived compared to single-crosslinked microgels. In particular, probiotic viability was highest in SPI/NaCMC-Al³⁺₈ microgels. These results indicate that the SPI/NaCMC-Al³⁺₈ microgels developed in this study can effectively protect L. acidophilus against the external environment.

Nanoscale bioconjugates: A review of the structural attributes of drug-loaded nanocarrier conjugates for selective cancer therapy

Nanobioconjugates are nanoscale drug delivery vehicles that have been conjugated to or decorated with biologically active targeting ligands. These targeting ligands can be antibodies, peptides, aptamers, or small molecules such as vitamins or hormones. Most research studies in this field have been devoted to targeting cancer. Moreover, the nanostructures can be designed with an additional level of targeting by being designed to be stimulus-responsive or "smart" by a judicious choice of materials to be incorporated into the hybrid nanostructures. This stimulus could be an acidic pH, raised temperature, enzyme, ultrasound, redox potential, an externally applied magnetic field, or laser irradiation. In this case, the smart capability can increase the accumulation at the tumor site or the on-demand drug release, while the ligand ensures selective binding to the tumor cells. The present review highlights some interesting studies classified according to the nanostructure material. These materials include natural substances (polysaccharides), multi-walled carbon nanotubes (and halloysite nanotubes), metal-organic frameworks and covalent-organic frameworks, metal nanoparticles (gold and silver), and polymeric micelles.

Expanding the Repertoire of Electrospinning: New and Emerging Biopolymers, Techniques, and Applications

Electrospinning has emerged as a versatile and accessible technology for fabricating polymer fibers, particularly for biological applications. Natural polymers or biopolymers (including synthetically derivatized natural polymers) represent a promising alternative to synthetic polymers, as materials for electrospinning. Many biopolymers are obtained from abundant renewable sources, are biodegradable, and possess inherent biological functions. This review surveys recent literature reporting new fibers produced from emerging biopolymers, highlighting recent developments in the use of sulfated polymers (including carrageenans and glycosaminoglycans), tannin derivatives (condensed and hydrolyzed tannins, tannic acid), modified collagen, and extracellular matrix extracts. The proposed advantages of these biopolymer-based fibers, focusing on their biomedical applications, are also discussed to highlight the use of new and emerging biopolymers (or new modifications to well-established ones) to enhance or achieve new properties for electrospun fiber materials.

A core-shell structured alginate hydrogel beads with tunable thickness of carboxymethyl cellulose coating for pH responsive drug delivery

pH-responsive core-shell structured composite hydrogel beads, composed of a alginate (ALG) core coated with carboxymethyl cellulose (CMC) shell (ALG@CMC), were prepared by using in-situ gel preparation technology as a drug delivery system. An anti-inflammatory drug, indomethacin was loaded into the formed hydrogels as a model drug. The resulting gel samples were characterized by Fourier transforms infrared (FTIR) spectroscopy, thermo-gravimetric (TG) analysis, and scanning electron microscopy (SEM). The mechanical stability of all samples in phosphate buffered solution (PBS, pH 7.4) was approximately measured through oscillation experiments. Swelling and controlled drug release behaviors of ALG@CMC beads compared with ALG were studied in simulating gastric fluid of pH 1.2 or intestinal fluid of pH 7.4 at 37 °C. Oscillation experiments proved that the mechanical stability of ALG@CMC beads could be significantly improved by the CMC shell layer. The swelling and drug release behaviors revealed that the swelling and drug release rate of ALG@CMC beads were obviously slower than that of simple-ALG and both have significant pH responsiveness. The cumulative drug release from ALG, ALG@CMC-1, ALG@CMC-2 and ALG@CMC-3 was about 100%, 67%, 46% and 37% in simulated intestinal fluid of pH 7.4, respectively, while the drug release reached only about 2.0% in simulating gastric fluid of pH 1.2 within 720 min. These developed materials could potentially be employed as a pH-responsive drug delivery device in vivo.[Formula: see text].

Carrageenan: A Wonder Polymer from Marine Algae for Potential Drug Delivery Applications

BACKGROUND

With the advancement in the field of medical science, the idea of sustained release of the therapeutic agents in the patient's body has remained a major thrust for developing advanced drug delivery systems (DDSs). The critical requirement for fabricating these DDSs is to facilitate the delivery of their cargos in a spatio-temporal and pharmacokinetically-controlled manner. Albeit the synthetic polymer-based DDSs normally address the above-mentioned conditions, their potential cytotoxicity and high cost have ultimately constrained their success. Consequently, the utilization of natural polymers for the fabrication of tunable DDSs owing to their biocompatible, biodegradable, and non-toxic nature can be regarded as a significant stride in the field of drug delivery. Marine environment serves as an untapped resource of varied range of materials such as polysaccharides, which can easily be utilized for developing various DDSs.

METHODS

Carrageenans are the sulfated polysaccharides that are extracted from the cell wall of red seaweeds. They exhibit an assimilation of various biological activities such as anti-thrombotic, anti-viral, anticancer, and immunomodulatory properties. The main aim of the presented review is threefold. The first one is to describe the unique physicochemical properties and structural composition of different types of carrageenans. The second is to illustrate the preparation methods of the different carrageenan-based macro- and micro-dimensional DDSs like hydrogels, microparticles, and microspheres respectively. Fabrication techniques of some advanced DDSs such as floating hydrogels, aerogels, and 3-D printed hydrogels have also been discussed in this review. Next, considerable attention has been paid to list down the recent applications of carrageenan-based polymeric architectures in the field of drug delivery.

RESULTS

Presence of structural variations among the different carrageenan types helps in regulating their temperature and ion-dependent sol-to-gel transition behavior. The constraint of low mechanical strength of reversible gels can be easily eradicated using chemical crosslinking techniques. Carrageenan based-microdimesional DDSs (e.g. microspheres, microparticles) can be utilized for easy and controlled drug administration. Moreover, carrageenans can be fabricated as 3-D printed hydrogels, floating hydrogels, and aerogels for controlled drug delivery applications.

CONCLUSION

In order to address the problems associated with many of the available DDSs, carrageenans are establishing their worth recently as potential drug carriers owing to their varied range of properties. Different architectures of carrageenans are currently being explored as advanced DDSs. In the near future, translation of carrageenan-based advanced DDSs in the clinical applications seems inevitable.

Carrageenan based hydrogels for drug delivery, tissue engineering and wound healing

Carrageenan is a class of naturally occurring sulphated polysaccharides, which is currently a promising candidate in tissue engineering and regenerative medicine as it resemblances native glycosaminoglycans. From pharmaceutical drug formulations to tissue engineered scaffolds, carrageenan has broad range of applications. Here we provide an overview of developing various forms of carrageenan based hydrogels. We focus on how these fabrication processes has an effect on physiochemical properties of the hydrogel. We outline the application of these hydrogels not only pertaining to sustained drug release but also their application in bone and cartilage tissue engineering as well as in wound healing and antimicrobial formulations. Administration of these hydrogels through various routes for drug delivery applications has been critically reviewed. Finally, we conclude by summarizing the current and future outlook that promotes the seaweed-derived polysaccharide as versatile, promising biomaterial for a variety of bioengineering applications.

Biopolymer-based strategies in the design of smart medical devices and artificial organs

Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.

Modulation of Lipid Digestion Profiles Using Filled Egg White Protein Microgels

Colloidal delivery systems are required to encapsulate, protect, and release active food ingredients, such as vitamins, nutraceuticals, and minerals. In this study, lipid droplets were encapsulated within biopolymer microgels fabricated from egg white proteins using an injection-gelation process. Confocal fluorescence microscopy indicated that lipid droplets were dispersed within a network of cross-linked proteins within the microgels. The properties of the lipid-loaded microgels were compared to those of simple oil-in-water emulsions stabilized by egg white proteins. Light scattering and microscopy measurements indicated that both delivery systems exhibited good stability under acid conditions (pH 3-5) but aggregated at higher pH values as a result of a reduction in electrostatic repulsion. Simulated gastrointestinal tract studies indicated that lipid droplets encapsulated within protein microgels were digested more slowly than free lipid droplets. Our results therefore suggest that egg white protein microgels may be useful for encapsulation and controlled release of hydrophobic bioactive agents.

Xylan-Modified-Based Hydrogels with Temperature/pH Dual Sensitivity and Controllable Drug Delivery Behavior

Among the natural macromolecules potentially used as the scaffold material in hydrogels, xylan has aroused great interest in many fields because of its biocompatibility, low toxicity, and biodegradability. In this work, new pH and thermoresponsive hydrogels were prepared by the cross-linking polymerization of maleic anhydride-modified xylan (MAHX) with N-isopropylacrylamide (NIPAm) and acrylic acid (AA) under UV irradiation to form MAHX-g-P(NIPAm-co-AA) hydrogels. The pore volume, the mechanical properties, and the release rate for drugs of hydrogels could be controlled by the degree of substitution of MAHX. These hydrogels were characterized by swelling ability, lower critical solution temperature (LCST), Fourier-transform infrared (FTIR), and SEM. Furthermore, the cumulative release rate was investigated for acetylsalicylic acid and theophylline, as well as the cytocompatibility MAHX-based hydrogels. Results showed that MAHX-based hydrogels exhibited excellent swelling-deswelling properties, uniform porous structure, and the temperature/pH dual sensitivity. In vitro, the cumulative release rate of acetylsalicylic acid for MAHX-based hydrogels was higher than that for theophylline, and in the gastrointestinal sustained drug release study, the acetylsalicylic acid release rate was extremely slow during the initial 3 h in the gastric fluid (24.26%), and then the cumulative release rate reached to 90.5% after sustained release for 5 h in simulated intestinal fluid. The cytotoxicity experiment demonstrated that MAHX-based hydrogels could promote cell proliferation and had satisfactory biocompatibility with NIH3T3 cells. These results indicated that MAHX-based hydrogels, as new drug carriers, had favorable behavior for intestinal-targeted drug delivery.

Synthesis of magnetic epichlorohydrin cross-linked carboxymethyl cellulose microspheres and their adsorption behavior for methylene blue

Epichlorohydrin cross-linked carboxymethyl cellulose microspheres (ECH/CMC) obtained by inverse suspension method and magnetic Fe₃O₄ nanoparticles encasing the ECH/CMC microspheres (M-ECH/CMC) obtained by two different methods were successfully prepared and compared. Their structures and morphologies were analyzed using polarizing microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The adsorption behaviors of M1-ECH/CMC for methylene blue (MB) in the single cationic dye wastewater, the cationic/anionic dye mixture in the absence or presence of co-existed additives (salt and surfactant) wastewater, were also investigated with UV-vis spectrometer. The results showed that the magnetic Fe₃O₄ nanoparticles were loaded readily in situ into ECH/CMC by specific, chemical interactions between COO^- groups of ECH/CMC and magnetic responsive Fe₃O₄. The Langmuir isotherm and pseudo-second-order kinetic model provide best correlation with the experimental data for the adsorption of MB onto ECH/CMC and M1-ECH/CMC microspheres, while the Langmuir isotherm and pseudo-first-order kinetic model for M2-ECH/CMC. These microspheres are easily recyclable and exhibit high desorption and adsorption, which suggests that they can be applied as potential environmental adsorbents.

pH-Responsive polymers

This review summarizes pH-responsive monomers, polymers and their derivative nano- and micro-structures including micelles, cross-linked micelles, microgels and hydrogels.