Study on poly(D,L-lactic) microspheres embedded in calcium alginate hydrogel beads as dual drug delivery systems

Construction of a dual-responsive dual-drug delivery platform based on the hybrids of mesoporous silica, sodium hyaluronate, chitosan and oxidized sodium carboxymethyl cellulose

An intelligent drug delivery platform based on the hybrids of mesoporous silica nanoparticles (MSN), sodium hyaluronate (HA), chitosan (CS) and oxidized sodium carboxymethyl cellulose (oxCMC) is developed, which can be used for dual-responsive dual-drug delivery. Hydrophilic cytarabine (Cyt) is first loaded into the mesopores of the aminated MSN (NH₂-MSN), which is encapsulated by the hydrogel of HA and cystamine (Cys) crosslinked via amidation. The Cyt encapsulated hydrogel which is denoted as Cyt/NH₂-MSN/HA is co-encapsulated with hydrophobic methotrexate (MTX) into the hydrogel of CS and oxCMC resulted from Schiff base reaction. Since the acylhydrazone bonds (-HC=N-) between CS and oxCMC are sensitive to pH and the disulfide bonds (-S-S-) in Cys are sensitive to glutathione (GSH), the resultant dual-drug encapsulated hydrogel, denoted as Cyt/NH₂-MSN/HA/MTX/CS/oxCMC, can be used for dual-responsive (pH and GSH) drug delivery. The results of cell viability demonstrate that the developed dual-drug encapsulated hydrogel has significantly higher efficacy of chemotherapy than that of single-drug (MTX or Cyt) encapsulated hydrogel.

Locust Bean Gum: Processing, Properties and Food Applications

Locust bean gum is derived from the seed endosperm of the Ceratonia siliqua carob tree and is known as locust bean or carob gum. Food, medicines, paper, textile, oil drilling, and cosmetic sectors all use it as an ingredient. Hydrogen bonding with water molecules makes locust bean gum useful in industrial settings. In addition, its dietary fibre activity helps regulate numerous health issues, including diabetes, bowel motions, heart disease and colon cancer. Locust bean gum production, processing, composition, characteristics, culinary applications, and health advantages are the subject of this article.

Alginate and alginate composites for biomedical applications

Alginate is an edible heteropolysaccharide that abundantly available in the brown seaweed and the capsule of bacteria such as Azotobacter sp. and Pseudomonas sp. Owing to alginate gel forming capability, it is widely used in food, textile and paper industries; and to a lesser extent in biomedical applications as biomaterial to promote wound healing and tissue regeneration. This is evident from the rising use of alginate-based dressing for heavily exuding wound and their mass availability in the market nowadays. However, alginate also has limitation. When in contact with physiological environment, alginate could gelate into softer structure, consequently limits its potential in the soft tissue regeneration and becomes inappropriate for the usage related to load bearing body parts. To cater this problem, wide range of materials have been added to alginate structure, producing sturdy composite materials. For instance, the incorporation of adhesive peptide and natural polymer or synthetic polymer to alginate moieties creates an improved composite material, which not only possesses better mechanical properties compared to native alginate, but also grants additional healing capability and promote better tissue regeneration. In addition, drug release kinetic and cell viability can be further improved when alginate composite is used as encapsulating agent. In this review, preparation of alginate and alginate composite in various forms (fibre, bead, hydrogel, and 3D-printed matrices) used for biomedical application is described first, followed by the discussion of latest trend related to alginate composite utilization in wound dressing, drug delivery, and tissue engineering applications.

Dielectric Analysis of Microcapsule-Immobilized Composite Capsules Suspension: Substances Release

Dielectric spectroscopy has unique advantages in monitoring drug release. In this work, a dielectric measurement was carried out on the release of the substances of microcapsule-immobilized composite capsules, which were fabricated by encapsulating the Perinereis aibuhitensis extract-loaded gum Arabic/gelatin microcapsules (PaE: GA/GE-MCs) in calcium alginate hydrogel (PaE: CA/GA/GE-CCs). We established the dielectric model of PaE: CA/GA/GE-CCs and got in-depth information on the systems. There are two relaxations in the dielectric spectroscopy, both of which are caused by interfacial polarization. The relaxation mechanisms correspond to the interfacial polarization of the PaE-loading core/calcium alginate shell interface and the calcium alginate shell/solution interface, respectively. Besides, the swelling of composite capsules and substance migration in the composite capsules were observed by analyzing phase parameters. Finally, the characteristic release of calcium alginate composite capsules was confirmed, and the substance release mechanism of composite capsules, namely, the swelling-diffusion mechanism, was obtained.

Specialty Tough Hydrogels and Their Biomedical Applications

Hydrogels have long been explored as attractive materials for biomedical applications given their outstanding biocompatibility, high water content, and versatile fabrication platforms into materials with different physiochemical properties and geometries. Nonetheless, conventional hydrogels suffer from weak mechanical properties, restricting their use in persistent load-bearing applications often required of materials used in medical settings. Thus, the fabrication of mechanically robust hydrogels that can prolong the lifetime of clinically suitable materials under uncompromising in vivo conditions is of great interest. This review focuses on design considerations and strategies to construct such tough hydrogels. Several promising advances in the proposed use of specialty tough hydrogels for soft actuators, drug delivery vehicles, adhesives, coatings, and in tissue engineering settings are highlighted. While challenges remain before these specialty tough hydrogels will be deemed translationally acceptable for clinical applications, promising preliminary results undoubtedly spur great hope in the potential impact this embryonic research field can have on the biomedical community.

Poly(hydroxybutyrate-co-hydroxyvalerate) microparticles embedded in κ-carrageenan/locust bean gum hydrogel as a dual drug delivery carrier

A novel composite hydrogel was prepared as a dual drug delivery carrier. Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microparticles were prepared to encapsulate simultaneously ketoprofen and mupirocin, as hydrophobic drug models. These microparticles were embedded in a physically crosslinked hydrogel of κ-carrageenan/locust bean gum. This composite hydrogel showed for both drugs a slower release than the obtained release from microparticles and hydrogel separately. The release of both drugs was observed during a period of 7 days at 37 °C. Different kinetic models were analyzed and the results indicated the best fitting to a Higuchi model suggesting that the release was mostly controlled by diffusion. Also, the drug loaded microparticles were spherical with average mean particle size of 1.0 μm, mesoporous, and distributed homogeneously in the hydrogel. The composite hydrogel showed a thermosensitive swelling behavior reaching 183% of swelling ratio at 37 °C. The composite hydrogel showed the elastic component to be higher than the viscous component, indicating characteristics of a strong hydrogel. The biocompatibility was evaluated with in vitro cytotoxicity assays and the results indicated that this composite hydrogel could be considered as a potential biomaterial for dual drug delivery, mainly for wound healing applications.

Nanocomposite Hydrogels: 3D Polymer-Nanoparticle Synergies for On-Demand Drug Delivery

Considerable progress in the synthesis and technology of hydrogels makes these materials attractive structures for designing controlled-release drug delivery systems. In particular, this review highlights the latest advances in nanocomposite hydrogels as drug delivery vehicles. The inclusion/incorporation of nanoparticles in three-dimensional polymeric structures is an innovative means for obtaining multicomponent systems with diverse functionality within a hybrid hydrogel network. Nanoparticle-hydrogel combinations add synergistic benefits to the new 3D structures. Nanogels as carriers for cancer therapy and injectable gels with improved self-healing properties have also been described as new nanocomposite systems.

Liposome-coated hydrogel spheres: delivery vehicles with tandem release from distinct compartments

We have fabricated unilamellar lipid bilayer VESicle-COated hydrogel spheres (VESCOgels) by carbodiimide-mediated coupling of liposomes bearing surface amines to core-shell hydrogel spheres bearing surface carboxyls. The amine-containing moiety, 3-O (2-aminoethoxyethyloxyethyl)carbamyl cholesterol (AECHO), was incorporated into large unilamellar vesicles (LUVs), diameter ∼100 nm, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). The hydrogel, diameter ∼ 1 μm, consisted of a core of poly(N-isopropyl acrylamide) (pNIPAM) and a shell of p(NIPAM-co-acrylic acid (AA)). Activation of these surface-displayed carboxyls with N-hydroxysuccinimidyl (NHS) esters permitted amine coupling upon addition of AECHO-containing POPC LUVs. Bilayer integrity of the hydrogel-bound LUVs was maintained, and fusion of LUVs did not occur. Fluorescence assays of the release of cobalt-calcein trapped within hydrogel-bound LUVs and of sodium fluorescein trapped within the hydrogel itself showed that each compartment retained its distinct release attributes: fast release from the microgel and slow release from the LUVs. It is envisioned that VESCOgels will be useful, therefore, in applications requiring temporally controlled delivery of distinct drugs.