Swelling behaviour and controlled drug release from cross-linked κ-carrageenan/NaCMC hydrogel by diffusion mechanism

Hyaluronic Acid-Based Nanosystems for CD44 Mediated Anti-Inflammatory and Antinociceptive Activity

The nervous and immune systems go hand in hand in causing inflammation and pain. However, the two are not mutually exclusive. While some diseases cause inflammation, others are caused by it. Macrophages play an important role in modulating inflammation to trigger neuropathic pain. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan that has a well-known ability to bind with the cluster of differentiation 44 (CD44) receptor on classically activated M1 macrophages. Resolving inflammation by varying the molecular weight of HA is a debated concept. HA-based drug delivery nanosystems such as nanohydrogels and nanoemulsions, targeting macrophages can be used to relieve pain and inflammation by loading antinociceptive drugs and enhancing the effect of anti-inflammatory drugs. This review will discuss the ongoing research on HA-based drug delivery nanosystems regarding their antinociceptive and anti-inflammatory effects.

Immunological response of polysaccharide nanogel-incorporating PEG hydrogels in an in vivo diabetic model

Cell-based therapies hold significant advantages in comparison with the traditional drug-based or injection-based treatments. However, for long-term functional cellular implants, immune acceptance must be established. To accomplish the acceptance of the implanted cells, various biomaterial systems have been studied. Nanogels have shown great potential for modulation of cellular microenvironments, acting as a physical barrier between the immune system and the implant. However, internalization of nano-scale materials by implanted cells is not desirable and is yet to be overcome. In this study, we incorporated acrylate modified cholesterol-bearing pullulan (CHPOA) nanogels into poly (ethylene glycol) diacrylate (PEGDA) hydrogels through covalent crosslinking, where we used visible light-induced photopolymerization. We characterized morphology and swelling properties of CHPOA incorporated PEG composite hydrogels using FE-SEM and gravimetric analysis. Also, we investigated the biocompatibility properties of composite hydrogels in vivo, where we used both healthy and diabetic mice. We induced diabetes in mice using a low dose streptozotocin (STZ) injections and implanted composite hydrogels in both diabetic and healthy mice through subcutaneous route. Immune cell infiltration of the retrieved tissue was examined through histological analysis, where we observed minimum immune response levels of 0-2 rareness, according to ISO standard of biological evaluation of medical devices. Our observation suggests that the composite hydrogel developed here can be used to introduce nanostructured domains into bulk hydrogels and that this system has potential to be used as immunologically acceptable composite material in cellular therapy without internalization of nanoparticles.

Alginate/Chitosan-Based Hydrogel Film Containing α-Mangostin for Recurrent Aphthous Stomatitis Therapy in Rats

Recurrent aphthous stomatitis (RAS) is a prevalent clinical disorder that causes mouth ulcers. Furthermore, corticosteroid treatment has been widely utilized for RAS therapy; however, it has side effects on the oral mucosa that limit its application. This study aimed to develop a novel RAS therapy with the natural ingredient α-mangostin, delivered by alginate and chitosan polymers-based hydrogel film (α-M Alg/Chi-HF). To prepare α-M Alg/Chi-HF, the solvent evaporation and casting methods were used, then characterized by using SEM, FTIR, and XRD. Based on the characterization studies, the α-M in α-M/EtOH Alg/Chi-HF with ethanol (EtOH) was found to be more homogenous compared to α-M in Alg/Chi-HF with distilled water (H2O) as a casting solvent. The in vitro viability study using NIH3T3 cells showed 100% viability of α-M Alg/Chi-HF (EtOH) and Alg/Chi-HF after 24 h incubation, indicating well tolerability of these hydrogel films. Interestingly, the in vivo studies using male white rats (Rattus norvegicus Berkenhout) proved that α-M/EtOH Alg/Chi-HF with a recovery of 81.47 ± 0.09% in seven days significantly more effective RAS therapy compared to control. These results suggest that α-M/EtOH Alg/Chi-HF has the potential as an alternative for RAS therapy.

Preparation and Characterization of Beads of Sodium Alginate/Carboxymethyl Chitosan/Cellulose Nanofiber Containing Porous Starch Embedded with Gallic Acid: An In Vitro Simulation Delivery Study

In this study, a system was designed that can encapsulate and deliver gallic acid (GA), which was composed of polysaccharide polymers based on sodium alginate (SA), carboxymethyl chitosan (CCT), and cellulose nanofibers (CN) and was assisted by porous starch. The compositions were characterized by rheology and zeta potentials, and the results showed that the materials used in this study could effectively guarantee the stability of the system. The morphology and chemical structure of the beads were characterized by SEM and FT-IR, the results indicated that the addition of CCT could effectively reduce the cracks and pores on the surface of the beads, which was beneficial to the encapsulation and delivery of GA. Moreover, the results of the swelling rate, release tests, and antioxidant tests also proved the effectiveness of the system. The pH response effect of SA/CN/CCT (SCC) beads and the protection of GA were superior, and the release rate of GA in simulated gastric fluid (SGF) was only 6.95%, while SA and SA/CN (SCN) beads reached 57.94% and 78.49%, respectively. In conclusion, the interpenetrating network polymers constructed by SA, CCT, and CN, which, combined with porous starch as a coating layer, can achieve the embedding and the delivery of GA.

Advances in the stimuli-responsive injectable hydrogel for controlled release of drugs

The stimuli-responsiveness of injectable hydrogel has been drastically developed for the controlled release of drugs and achieved encouraging curative effects in a variety of diseases including wounds, cardiovascular diseases and tumors. The gelation, swelling and degradation of such hydrogels respond to endogenous biochemical factors (such as pH, reactive oxygen species, glutathione, enzymes, glucose) and/or to exogenous physical stimulations (like light, magnetism, electricity and ultrasound), thereby accurately releasing loaded drugs in response to specifically pathological status and as desired for treatment plan and thus improving therapeutic efficacy effectively. In this paper, we give a detailed introduction of recent progresses in responsive injectable hydrogels and focus on the design strategy of various stimuli-sensitivities and their resultant alteration of gel dissociation and drug liberation behaviour. Their application in disease treatment is also discussed. This article is protected by copyright. All rights reserved.

Copolymer Involving 2-Hydroxyethyl Methacrylate and 2-Chloroquinyl Methacrylate: Synthesis, Characterization and In Vitro 2-Hydroxychloroquine Delivery Application

The Poly(2-chloroquinyl methacrylate-co-2-hydroxyethyl methacrylate) (CQMA-co-HEMA) drug carrier system was prepared with different compositions through a free-radical copolymerization route involving 2-chloroquinyl methacrylate (CQMA) and 2-hydroxyethyl methacrylate) (HEMA) using azobisisobutyronitrile as the initiator. 2-Chloroquinyl methacrylate monomer (CQMA) was synthesized from 2-hydroxychloroquine (HCQ) and methacryloyl chloride by an esterification reaction using triethylenetetramine as the catalyst. The structure of the CQMA and CQMA-co-HEMA copolymers was confirmed by a CHN elementary analysis, Fourier transform infra-red (FTIR) and nuclear magnetic resonance (NMR) analysis. The absence of residual aggregates of HCQ or HCQMA particles in the copolymers prepared was confirmed by a differential scanning calorimeter (DSC) and XR-diffraction (XRD) analyses. The gingival epithelial cancer cell line (Ca9-22) toxicity examined by a lactate dehydrogenase (LDH) assay revealed that the grafting of HCQ onto PHEMA slightly affected (4.2-9.5%) the viability of the polymer carrier. The cell adhesion and growth on the CQMA-co-HEMA drug carrier specimens carried out by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay revealed the best performance with the specimen containing 3.96 wt% HCQ. The diffusion of HCQ through the polymer matrix obeyed the Fickian model. The solubility of HCQ in different media was improved, in which more than 5.22 times of the solubility of HCQ powder in water was obtained. According to Belzer, the in vitro HCQ dynamic release revealed the best performance with the drug carrier system containing 4.70 wt% CQMA.

Recent advances in polymeric transdermal drug delivery systems

Transdermal delivery has proven to be one of the most favorable methods among novel drug delivery systems. Since drugs administered by transdermal delivery systems avoid the gastrointestinal tract, and thus avoid conversion by the liver, the likelihood of liver dysfunction and gastrointestinal tract irritation as side effects is low. Drug delivery through the skin has other advantages, such as maintaining an effective rate of drug delivery over time, a steady rate of circulation, and the benefits of a passive delivery system and diffusion. Transdermal drug delivery is achieved using patches which consist of different and specific layers. In the last few decades, many types of patches have been approved worldwide, such as medical plasters, which have been generally applied to the skin for localized diseases. Such patches can be traced back to ancient China (around 2000 BCE) and are the early precursors of today's transdermal patches. With the help of effective design, materials, manufacturing, and evaluation, a large number of drugs can now be administered using this valuable advanced technology. This study reviews different types of polymer patches, their advantages and disadvantages, and different studies related to transdermal drug delivery methods, and the advantages and disadvantages of each method. Different mechanisms of transdermal drug delivery system with patches are also discussed.

A Novel Method for Preparation of Carrageenan/Fish Scale Collagen/Allopurinol Biocomposite Film

Biopolymers such as carrageenan or collagen can be used as carriers for loading a drug to enhance a drug’s bioavailability. In this work, allopurinol was loaded on a carrageenan/collagen blend and the carrageenan/collagen/allopurinol (CCA) biocomposite films were prepared using the ionic gelation method combined with the 3D printing method using carrageenan/collagen/allopurinol gel as a 3D printing ink material. The advantages of the 3D printing method are the ease in shaping the design of films and the ease in controlling the thickness of films. The results of infrared (IR) spectroscopy and field emission scanning electron microscopy (FESEM) analyses showed that the CCA biocomposite films have a regular structure, and the functional groups of components in the biocomposites can interact with each other. After 30 minutes of immersion in distilled water and pH buffer solution, the biocomposite films swelled and disintegrated. The carrageenan/collagen blend can control the release of allopurinol in simulated body fluids. In addition, the drug release kinetic models reflecting the release process of allopurinol from CCA biocomposite films in simulated body fluids have also been calculated.

Formulation Development of a Food-Graded Curcumin-Loaded Medium Chain Triglycerides-Encapsulated Kappa Carrageenan (CUR-MCT-KC) Gel Bead Based Oral Delivery Formulation

In recent years, curcumin has been a major research endeavor in food and biopharmaceutical industries owing to its miscellaneous health benefits. There is an increasing amount of research ongoing in the development of an ideal curcumin delivery system to resolve its limitations and further enhance its solubility, bioavailability and bioactivity. The emergence of food-graded materials and natural polymers has elicited new research interests into enhanced pharmaceutical delivery due to their unique properties as delivery carriers. The current study is to develop a natural and food-graded drug carrier with food-derived MCT oil and a seaweed-extracted polymer called k-carrageenan for oral delivery of curcumin with improved solubility, high gastric resistance, and high encapsulation of curcumin. The application of k-carrageenan as a structuring agent that gelatinizes o/w emulsion is rarely reported and there is so far no MCT-KC system established for the delivery of hydrophobic/lipophilic molecules. This article reports the synthesis and a series of in vitro bio-physicochemical studies to examine the performance of CUR-MCT-KC as an oral delivery system. The solubility of CUR was increased significantly using MCT with a good encapsulation efficiency of 73.98 ± 1.57% and a loading capacity of 1.32 ± 0.03 mg CUR/mL MCT. CUR was successfully loaded in MCT-KC, which was confirmed using FTIR and SEM with good storage and thermal stability. Dissolution study indicated that the solubility of CUR was enhanced two-fold using heated MCT oil as compared to naked or unformulated CUR. In vitro release study revealed that encapsulated CUR was protected from premature burst under simulated gastric environment and released drastically in simulated intestinal condition. The CUR release was active at intestinal pH with the cumulative release of >90% CUR after 5 h incubation, which is the desired outcome for CUR absorption under human intestinal conditions. A similar release profile was also obtained when CUR was replaced with beta-carotene molecules. Hence, the reported findings demonstrate the potencies of MCT-KC as a promising delivery carrier for hydrophobic candidates such as CUR.

Modeling the release of food bioactive ingredients from carriers/nanocarriers by the empirical, semiempirical, and mechanistic models

The encapsulation process has been utilized in the field of food technology to enhance the technofunctional properties of food products and the delivery of nutraceutical ingredients via food into the human body. The latter application is very similar to drug delivery systems. The inherent sophisticated nature of release mechanisms requires the utilization of mathematical equations and statistics to predict the release behavior during the time. The science of mathematical modeling of controlled release has gained a tremendous advancement in drug delivery in recent years. Many of these modeling methods could be transferred to food. In order to develop and design enhanced food controlled/targeted bioactive release systems, understanding of the underlying physiological and chemical processes, mechanisms, and principles of release and applying the knowledge gained in the pharmaceutical field to food products is a big challenge. Ideally, by using an appropriate mathematical model, the formulation parameters could be predicted to achieve a specific release behavior. So, designing new products could be optimized. Many papers are dealing with encapsulation approaches and evaluation of the impact of process and the utilized system on release characteristics of encapsulated food bioactives, but still, there is no deep insight into the mathematical release modeling of encapsulated food materials. In this study, information gained from the pharmaceutical field is collected and discussed to investigate the probable application in the food industry.

An overview on the mathematical modeling of hydrogels' behavior for drug delivery systems

Hydrogels-based systems (HBSs) for drug delivery are nowadays extensively used and the interest in modeling their behavior is dramatically increasing. In this review a critical overview on the modeling approaches is given, quantitatively and qualitatively analyzing the publications on the subject, the trend of the publications per year and the type of modeling approaches. It was found that, despite the drug release fitting models (i.e. Higuchi's equation) are the most abundant, their use for HBSs is decreasing in the last years and luckily, considering the limiting assumption on which they were built, they will be confined to simple mathematical fitting equations. Within the mechanistic models the "multi-component" with the swelling approximation (mass transport only) and with the mechanics (fully coupled) are experiencing the highest growth rate, with much more interest toward the last one that, in the next years could be able to provide a first principles model. Statistical models, especially based on the response surface methodology, are rapidly spreading in the scientific community mainly thanks to their ability to be predictive, regardless of the phenomenology, in the analyzed design space with very low efforts. Neural Networks models for HBSs, in countertrend with their use in the pharmaceutical industry, have never take off preferring less data demanding statistical models.

Direct ink writing with high-strength and swelling-resistant biocompatible physically crosslinked hydrogels

The 3D printing of physically crosslinked hydrogel architectures with high strength and swelling resistance is achieved with biocompatible PVA and natural κ-carrageenan hybrid inks.

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.

Polysaccharide matrices used in 3D in vitro cell culture systems

Polysaccharides comprise a diverse class of polymeric materials with a history of proven biocompatibility and continual use as biomaterials. Recent focus on new matrices appropriate for three-dimensional (3D) cell culture offers new opportunities to apply polysaccharides as extracellular matrix mimics. However, chemical and structural bases for specific cell-polysaccharide interactions essential for their utility as 3-D cell matrices are not well defined. This review describes how these naturally sourced biomaterials satisfy several key properties for current 3D cell culture needs and can also be synthetically modified or blended with additional components to tailor their cell engagement properties. Beyond their benign interactions with many cell types in cultures, their economical and high quality sourcing, optical clarity for ex situ analytical interrogation and in situ gelation represent important properties of these polymers for 3D cell culture applications. Continued diversification of their versatile glycan chemistry, new bio-synthetic sourcing strategies and elucidation of new cell-specific properties are attractive to expand the polysaccharide polymer utility for cell culture needs. Many 3D cell culture priorities are addressed with the portfolio of polysaccharide materials available and under development. This review provides a critical analysis of their properties, capabilities and challenges in 3D cell culture applications.

Carrageenan Based Bionanocomposites as Drug Delivery Tool with Special Emphasis on the Influence of Ferromagnetic Nanoparticles

Over the past few years, considerable attention has been focused on carrageenan based bionanocomposites due to their multifaceted properties like biodegradability, biocompatibility, and nontoxicity. Moreover, these composites can be tailored according to the desired purpose by using different nanofillers. The role of ferromagnetic nanoparticles in drug delivery is also discussed here in detail. Moreover, this article also presents a short review of recent research on the different types of the carrageenan based bionanocomposites and applications.

Synthesis and characterization of modified carrageenan microparticles for the removal of pharmaceuticals from aqueous solutions

In the present study, carrageenan microparticles were synthesized using spray-drying method and used as biosorbents for the removal of pharmaceutical compounds. The cross-linking reaction of iota-carrageenan (iCAR) and kappa-carrageenan (kCAR) with glutaraldehyde (GLA) at different concentrations (2.5% or 5% (w/w), mass of GLA per mass of CAR) was studied (iCAR/GLA2.5, iCAR/GLA5, kCAR/GLA2.5, kCAR/GLA5). The physicochemical properties of the novel cross-linked polymers were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Swelling studies were in accordance with the polymer properties, showing the lowest swelling degree (19%) by using the iCAR/GLA5 microparticles. The optimal kCAR/GLA5 microparticles were successfully employed for the removal of Metoprolol (MTPL) from aqueous samples. The adsorption capacity of the adsorbents was investigated using a batch adsorption procedure and the kinetics and thermodynamics of the adsorption process were further investigated. It was found that the adsorption isotherms agree well with the Langmuir-Freundlich model. The maximum adsorption capacity (Qm) was achieved in pH 6, whereas an increase of Qm was observed increasing the temperature (from 109 at 20°C to 178 mg/g at 40°C). Kinetic studies showed that the adsorption process on iCAR/GLA5 microparticles followed pseudo-second-order rate mechanism. Finally, a new phenomenological model of the adsorption process was proposed in order to extract information on the relevant sub-processes.

Review for carrageenan-based pharmaceutical biomaterials: favourable physical features versus adverse biological effects

Carrageenan (CRG) is a family of natural polysaccharides derived from seaweeds and has widely been used as food additives. In the past decade, owing to its attractive physicochemical properties, CRG has been developed into versatile biomaterials vehicles for drug delivery. Nevertheless, studies also emerged to reveal its adverse effects on the biological system. In this review, we critically appraise the latest literature (two thirds since 2008) on the development of CRG-based pharmaceutical vehicles and the perspective of using CRG for broader biomedical applications. We focus on how current strategies exploit the unique gelling mechanisms, strong water absorption and abundant functional groups of the three major CRG varieties. Notably, CRG-based matrices are demonstrated to increase drug loading and drug solubility, enabling release of orally administrated drugs in zero-order or in a significantly prolonged period. Other amazing features, such as pH-sensitivity and adhesive property, of CRG-based formulations are also introduced. Finally, we discuss the adverse influence of CRG on the human body and then suggest some future directions for the development of CRG-based biomaterials for broader applications in biomedicine.

Fabrication of endothelial cell-laden carrageenan microfibers for microvascularized bone tissue engineering applications

Recent achievements in the area of tissue engineering (TE) have enabled the development of three-dimensional (3D) cell-laden hydrogels as in vitro platforms that closely mimic the 3D scenario found in native tissues. These platforms are extensively used to evaluate cellular behavior, cell-cell interactions, and tissue-like formation in highly defined settings. In this study, we propose a scalable and flexible 3D system based on microsized hydrogel fibers that might be used as building blocks for the establishment of 3D hydrogel constructs for vascularized bone TE applications. For this purpose, chitosan (CHT) coated κ-carrageenan (κ-CA) microfibers were developed using a two-step procedure involving ionotropic gelation (for the fiber formation) of κ-CA and its polyelectrolyte complexation with CHT (for the enhancement of fiber stability). The performance of the obtained fibers was assessed regarding their swelling and stability profiles, as well as their ability to carry and, subsequently, promote the outward release of microvascular-like endothelial cells (ECs), without compromising their viability and phenotype. Finally, the possibility of assembling and integrating these cell-laden fibers within a 3D hydrogel matrix containing osteoblast-like cells was evaluated. Overall, the obtained results demonstrate the suitability of the microsized κ-CA fibers to carry and deliver phenotypically apt microvascular-like ECs. Furthermore, it is shown that it is possible to assemble these cell-laden microsized fibers into 3D heterotypic hydrogels constructs. This in vitro 3D platform provides a versatile approach to investigate the interactions between multiple cell types in controlled settings, which may open up novel 3D in vitro culture techniques to better mimic the complexity of tissues.

Hydrogels for controlled pulmonary delivery

A significant number of research articles have focused on pulmonary delivery as an alternative administration route owing to no first-pass metabolism, low protease activity, thin epithelium barrier and large surface area in the lung system. Controlled release in the pulmonary delivery system further reduces loading dose, frequency of dosing and systemic side effects, and also increases duration of action and patient compliance. Compared with other microparticles used in controlled-release pulmonary administration, hydrogels (3D polymeric matrix networks) have recently been investigated due to their swelling and mucoadhesive properties that could help bypass pulmonary delivery barriers. This review introduces controlled-release drug delivery to the lung, followed by a summary of currently available approaches for controlled-release pulmonary drug delivery. Lastly, the origin, advantages, detailed applications and concerns of hydrogels in pulmonary delivery are discussed.