Silica-coated calcium pectinate beads for colonic drug delivery

Pectin hydrogels for controlled drug release: Recent developments and future prospects

Pectin hydrogels have emerged as a highly promising medium for the controlled release of pharmaceuticals in the dynamic field of drug delivery. The present review sheds light on the broad range of applications and potential of pectin-based hydrogels in pharmaceutical formulations. Pectin, as a biopolymer, is a versatile candidate for various drug delivery systems because of its wide range of properties and characteristics. The information provided on formulation strategies and crosslinking techniques provides researchers with tools to improve drug entrapment and controlled release. Furthermore, this review provides a more in-depth understanding of the complex factors influencing drug release from pectin hydrogels, such as the impact of environmental conditions and drug-specific characteristics. Pectin hydrogels demonstrate adaptability across diverse domains, ranging from applications in oral and transdermal drug delivery to contributions in wound healing, tissue engineering, and ongoing clinical trials. While standardization and regulatory compliance remain significant challenges, the future of pectin hydrogels appears to be bright, opening up new possibilities for advanced drug delivery systems.

Recent progress and treatment strategy of pectin polysaccharide based tissue engineering scaffolds in cancer therapy, wound healing and cartilage regeneration

Natural polymers and its mixtures in the form of films, sponges and hydrogels are playing a major role in tissue engineering and regenerative medicine. Hydrogels have been extensively investigated as standalone materials for drug delivery purposes as they enable effective encapsulation and sustained release of drugs. Biopolymers are widely utilised in the fabrication of hydrogels due to their safety, biocompatibility, low toxicity, and regulated breakdown by human enzymes. Among all the biopolymers, polysaccharide-based polymer is well suited to overcome the limitations of traditional wound dressing materials. Pectin is a polysaccharide which can be extracted from different plant sources and is used in various pharmaceutical and biomedical applications including cartilage regeneration. Pectin itself cannot be employed as scaffolds for tissue engineering since it decomposes quickly. This article discusses recent research and developments on pectin polysaccharide, including its types, origins, applications, and potential demands for use in AI-mediated scaffolds. It also covers the materials-design process, strategy for implementation to material selection and fabrication methods for evaluation. Finally, we discuss unmet requirements and current obstacles in the development of optimal materials for wound healing and bone-tissue regeneration, as well as emerging strategies in the field.

Strategies for Anisotropic Fibrillar Hydrogels: Design, Cell Alignment, and Applications in Tissue Engineering

Efficient cellular alignment in biomaterials presents a considerable challenge, demanding the refinement of appropriate material morphologies, while ensuring effective cell-surface interactions. To address this, biomaterials are continuously researched with diverse coatings, hydrogels, and polymeric surfaces. In this context, we investigate the influence of physicochemical parameters on the architecture of fibrillar hydrogels that significantly orient the topography of flexible hydrogel substrates, thereby fostering cellular adhesion and spatial organization. Our Review comprehensively assesses various techniques for aligning polymer fibrils within hydrogels, specifically interventions applied during and after the cross-linking process. These methodologies include mechanical strains, precise temperature modulation, controlled fluidic dynamics, and chemical modulators, as well as the use of magnetic and electric fields. We highlight the intrinsic appeal of these methodologies in fabricating cell-aligning interfaces and discuss their potential implications within the fields of biomaterials and tissue engineering, particularly concerning the pursuit of optimal cellular alignment.

Chitosan and Pectin Hydrogels for Tissue Engineering and In Vitro Modeling

Hydrogels are fascinating biomaterials that can act as a support for cells, i.e., a scaffold, in which they can organize themselves spatially in a similar way to what occurs in vivo. Hydrogel use is therefore essential for the development of 3D systems and allows to recreate the cellular microenvironment in physiological and pathological conditions. This makes them ideal candidates for biological tissue analogues for application in the field of both tissue engineering and 3D in vitro models, as they have the ability to closely mimic the extracellular matrix (ECM) of a specific organ or tissue. Polysaccharide-based hydrogels, because of their remarkable biocompatibility related to their polymeric constituents, have the ability to interact beneficially with the cellular components. Although the growing interest in the use of polysaccharide-based hydrogels in the biomedical field is evidenced by a conspicuous number of reviews on the topic, none of them have focused on the combined use of two important polysaccharides, chitosan and pectin. Therefore, the present review will discuss the biomedical applications of polysaccharide-based hydrogels containing the two aforementioned natural polymers, chitosan and pectin, in the fields of tissue engineering and 3D in vitro modeling.

Fibrin-Rhamnogalacturonan I Composite Gel for Therapeutic Enzyme Delivery to Intestinal Tumors

Therapy of colorectal cancer with protein drugs, including targeted therapy using monoclonal antibodies, requires the preservation of the drug's structure and activity in the gastrointestinal tract or bloodstream. Here, we confirmed experimentally the fundamental possibility of creating composite protein-polysaccharide hydrogels based on non-degrading rhamnogalacturonan I (RG) and fibrin as a delivery vehicle for antitumor RNase binase. The method is based on enzymatic polymerization of fibrin in the presence of RG with the inclusion of liposomes, containing an encapsulated enzyme drug, into the gel network. The proposed method for fabricating a gel matrix does not require the use of cytotoxic chemical cross-linking agents and divalent cations, and contains completely biocompatible and biodegradable components. The process proceeds under physiological conditions, excluding the effect of high temperatures, organic solvents and ultrasound on protein components. Immobilization of therapeutic enzyme binase in the carrier matrix by encapsulating it in liposomes made from uncharged lipid made it possible to achieve its prolonged release with preservation of activity for a long time. The release time of binase from the composite carrier can be regulated by variation of the fibrin and RG concentration.

Recent advances on biomedical applications of pectin-containing biomaterials

There is a growing demand for biomaterials developing with novel properties for biomedical applications hence, hydrogels with 3D crosslinked polymeric structures obtained from natural polymers have been deeply inspected in this field. Pectin a unique biopolymer found in the cell walls of fruits and vegetables is extensively used in the pharmaceutical, food, and textile industries due to its ability to form a thick gel-like solution. Considering biocompatibility, biodegradability, easy gelling capability, and facile manipulation of pectin-based biomaterials; they have been thoroughly investigated for various potential biomedical applications including drug delivery, wound healing, tissue engineering, creation of implantable devices, and skin-care products.

Pectin in biomedical and drug delivery applications: A review

Natural macromolecules have attracted increasing attention due to their biocompatibility, low toxicity, and biodegradability. Pectin is one of the few polysaccharides with biomedical activity, consequently a candidate in biomedical and drug delivery Applications. Rhamnogalacturonan-II, a smaller component in pectin, plays a major role in biomedical activities. The ubiquitous presence of hydroxyl and carboxyl groups in pectin contribute to their hydrophilicity and, hence, to the favorable biocompatibility, low toxicity, and biodegradability. However, pure pectin-based materials present undesirable swelling and corrosion properties. The hydrophilic groups, via coordination, electrophilic addition, esterification, transesterification reactions, can contribute to pectin's physicochemical properties. Here the properties, extraction, and modification of pectin, which are fundamental to biomedical and drug delivery applications, are reviewed. Moreover, the synthesis, properties, and performance of pectin-based hybrid materials, composite materials, and emulsions are elaborated. The comprehensive review presented here can provide valuable information on pectin and its biomedical and drug delivery applications.

Fabrication of self-healing pectin/chitosan hybrid hydrogel via Diels-Alder reactions for drug delivery with high swelling property, pH-responsiveness, and cytocompatibility

Self-healing hydrogels with pH-responsiveness could protect loaded drugs from being destroyed till it arrives to the target. The pectin-based hydrogel is a candidate due to the health benefit, anti-inflammation, antineoplastic activity, nontoxicity, and biospecific degradation, et al. However, the abundant existence of water-soluble branched heteropolysaccharide chains influenced its performance resulting in limitation of the potential. In the present study, we prepared a series of self-healing pectin/chitosan hydrogels via the Diels-Alder reaction. Moreover, pectin/chitosan composite hydrogel was prepared as a contrast. By comparison, it can be seen that the Diels-Alder reaction greatly improved the cross-linking density of hydrogels. The self-healing experiments showed excellent self-healing performance. In different swelling mediums, significant transformation in the swelling ratio was shown, indicating well-swelling property, pH- and thermo-responsiveness. The drug loading and release studies presented high loading efficiency and sustained release performance. The cytotoxicity assay that showed a high cell proliferation ratio manifested great cytocompatibility.

Current Film Coating Designs for Colon-Targeted Oral Delivery

Colon-targeted oral delivery has recently attracted a substantial number of studies on both systemic and local treatments. Among approaches for colonic delivery, film coatings have been demonstrated as effective elements of the drug delivery systems because they can integrate multiple release strategies, such as pH-controlled release, time-controlled release and enzyme-triggered release. Moreover, coating layer modulations, natural film materials and nanoparticle coatings have been vigorously investigated with promising applications. This review aims to describe the primary approaches for improving drug delivery to the colon in the last decade. The outstanding importance of current developments in film coatings will advance dosage form designs and lead to the development of efficient colon-targeted oral delivery systems.

Silica-coated calcium pectinate formulations for controlling carbendazim release: water and soil release studies

This study aims to encapsulate the fungicide carbendazim using a biodegradable polymer (pectin). First, we have obtained calcium pectinate beads (CPG-Carb) by ionotropic gelation using calcium ions as a crosslinking agent. These beads were then coated with silica starting from tetraethoxysilane (TEOS), by a sol-gel process to form hybrid beads (CPG-Carb-SG). The morphology, composition and structure of both beads were characterized and the controlled release assays of the fungicide were studied in both water and soil columns. The encapsulation efficiency for CPG-Carb was slightly higher (75%) compared to CPG-Carb-SG (67%) due to carbendazim loss during the impregnation and condensation steps. The release rate in water and soil columns was about 4 times lower for CPG-Carb-SG than CPG-Carb demonstrating the efficiency of the silica coating to delay the release of carbendazim. Moreover, the release of CPG-Carb-SG is due to the erosion of the silica layer during the first two weeks. After this period, the silica layer was degraded, and the release is then controlled by the swelling of the organic part of the bead as observed for CPG-Carb. Finally, the biodegradability of the pectin, and the release profile make such systems promising candidates for sustained and economical pesticide delivery systems.

Silica coating of carboxymethyl tamarind kernel polysaccharide beads to modify the release characteristics

In present study, the release characteristics of ibuprofen-loaded carboxymethyl tamarind kernel polysaccharide beads were modified by coating with silica. The influence of concentrations of carboxymethyl tamarind kernel polysaccharide, calcium chloride and tetraethoxysilane on the % entrapment and in vitro release of ibuprofen was optimized using response surface methodology. The coating of beads with silica restricted the drug release from the beads but at the same time the ethanol formed as by-product of the sol gel process leached out the drug. The optimized batch of beads were prepared using carboxymethyl tamarind kernel powder-12.5 (%, w/v), calcium chloride-10.12 (%, w/v) and coated with tetraethoxysilane-0.25 M, entrapped 89.2% and released 92% of drug over 24 h. Energy dispersive X-ray analysis confirmed the coating of silica on the beads. The coating with silica shielded the crevices on the surface of beads but it did not elicit any significant change in thermal stability of beads. Further, in vitro release was found to be in good agreement with the swelling study. Modeling analysis revealed that ibuprofen was released from the beads following zero-order kinetics with erosion of the matrix as the main mechanism of drug release. Thus, silica coating provides a facile strategy to formulate sustained release formulations.

In situ follow-up of hybrid alginate-silicate microbeads formation by linear rheology

Hybrid alginate-silicate microbeads of about 10-20 μm were synthesized by combining alginate crosslinking, silica condensation in a one pot approach using a food grade emulsion as template. A fine tuning of the formulation composition (alginate, silica and calcium sources) is necessary in order to obtain core-shell microbeads instead of unshaped and irregular fragments or even perforated spherical beads. Importantly, in situ linear rheology provides insights into the reaction mechanism as a result of the rheological fingerprint profile obtained during beads formation.

Original behavior of L. rhamnosus GG encapsulated in freeze-dried alginate–silica microparticles revealed under simulated gastrointestinal conditions

Metabolically inactive in the upper GIT, encapsulated LGG boost their metabolism and better colonize the colon compared with free bacteria.

Rhamnogalacturonan-I Based Microcapsules for Targeted Drug Release

Drug targeting to the colon via the oral administration route for local treatment of e.g. inflammatory bowel disease and colonic cancer has several advantages such as needle-free administration and low infection risk. A new source for delivery is plant-polysaccharide based delivery platforms such as Rhamnogalacturonan-I (RG-I). In the gastro-intestinal tract the RG-I is only degraded by the action of the colonic microflora. For assessment of potential drug delivery properties, RG-I based microcapsules (~1 μm in diameter) were prepared by an interfacial poly-addition reaction. The cross-linked capsules were loaded with a fluorescent dye (model drug). The capsules showed negligible and very little in vitro release when subjected to media simulating gastric and intestinal fluids, respectively. However, upon exposure to a cocktail of commercial RG-I cleaving enzymes, ~ 9 times higher release was observed, demonstrating that the capsules can be opened by enzymatic degradation. The combined results suggest a potential platform for targeted drug delivery in the terminal gastro-intestinal tract.

Core–shell alginate@silica microparticles encapsulating probiotics

Lactobacillus rhamnosus GG (LGG) was encapsulated in core–shell alginate–silica microcapsules by coating the electrosprayed ionogel with a silica shell via hydrolysis/condensation of alkoxysilane precursors.

Novel pectin-based carriers for colonic drug delivery

Pectin-based hydrogel carriers have been studied and shown to have promising applications for drug delivery to the lower GI tract, especially to the colonic region. However, making sure these hydrogel carriers can pass through the upper GI tract and reach the targeted regions, after oral administration, still remains a challenge to overcome. A solution to this problem is to promote stronger cross-linking interactions within the pectin-based hydrogel network. The combined usage of a divalent cation (Ca(2+)) and the cationic biopolymer oligochitosan has shown to improve the stability of pectin-based hydrogel systems - suggesting that these two cross-linkers may be used to eventually help improve pectin-based hydrogel systems for colonic drug delivery methods.

Optimizing nanomedicine pharmacokinetics using physiologically based pharmacokinetics modelling

The delivery of therapeutic agents is characterized by numerous challenges including poor absorption, low penetration in target tissues and non-specific dissemination in organs, leading to toxicity or poor drug exposure. Several nanomedicine strategies have emerged as an advanced approach to enhance drug delivery and improve the treatment of several diseases. Numerous processes mediate the pharmacokinetics of nanoformulations, with the absorption, distribution, metabolism and elimination (ADME) being poorly understood and often differing substantially from traditional formulations. Understanding how nanoformulation composition and physicochemical properties influence drug distribution in the human body is of central importance when developing future treatment strategies. A helpful pharmacological tool to simulate the distribution of nanoformulations is represented by physiologically based pharmacokinetics (PBPK) modelling, which integrates system data describing a population of interest with drug/nanoparticle in vitro data through a mathematical description of ADME. The application of PBPK models for nanomedicine is in its infancy and characterized by several challenges. The integration of property-distribution relationships in PBPK models may benefit nanomedicine research, giving opportunities for innovative development of nanotechnologies. PBPK modelling has the potential to improve our understanding of the mechanisms underpinning nanoformulation disposition and allow for more rapid and accurate determination of their kinetics. This review provides an overview of the current knowledge of nanomedicine distribution and the use of PBPK modelling in the characterization of nanoformulations with optimal pharmacokinetics.

Dispersive evaluation and surface chemistry of advanced, multifunctional silica/lignin hybrid biomaterials

Advanced silica/lignin hybrid biomaterials were obtained using hydrated or fumed silicas (Aerosil®200) and Kraft lignin as precursors, which is a cheap and biodegradable natural polymer. To extend the possible range of applications, the silicas were first modified with N-2-(aminoethyl)-3-aminopropyltrimethoxsysilane, and then with Kraft lignin, which had been oxidized with sodium periodate. The SiO2/lignin hybrids and precursors were characterised by means of determination of their physicochemical and dispersive-morphological properties. The effectiveness of silica binding to lignin was verified by FT-IR spectroscopy. The zeta potential value provides relevant information regarding interactions between colloid particles. Measurement of the zeta potential values enabled an indirect assessment of stability for the studied hybrid systems. Determination of zeta potential and density of surface charge also permitted the quantitative analysis of changes in surface charge, and indirectly confirmed the effectiveness of the proposed method for synthesis of SiO2/lignin hybrid materials. A particularly attractive feature for practical use is their stability, especially electrokinetic stability. It is expected that silica/lignin hybrids will find a wide range of applications (polymer fillers, biosorbents, electrochemical sensors), as they combine the unique properties of silica with the specific structural features of lignin. This makes these hybrids biomaterials advanced and multifunctional.