Drug delivery system based on PVA and clay for potential treatment of COVID-19

Amoxicillin-loaded bionanocomposite hydrogels: swelling, dehydration, and in vitro drug release kinetics and mechanism

This study deals with preparing and characterizing polyvinyl alcohol/egg white/montmorillonite bionanocomposite hydrogels as antibacterial drug delivery systems. The cyclic freezing/thawing method was utilized to fabricate the hydrogels. To study the performance of the prepared hydrogels as drug delivery systems, amoxicillin, as a model antibiotic drug, was loaded into the hydrogels by mixing with the precursor polymer solution and gelation. From the diverse microstructural characterization techniques, i.e. XRD, SEM, AFM, DLS, and gel fraction estimation, it was possible to infer that montmorillonite has been successfully incorporated into the hydrogel network and acted as an additional crosslinker to bind the chains of egg white and polyvinyl alcohol. Scrutinizing the physical properties of the produced hydrogels demonstrated that increasing incorporated montmorillonite content adversely affects the prepared hydrogels' swelling ability and prolongs their dehydration period. Additionally, the Swelling characteristics of the hydrogels were evaluated at different pHs. Results showed an increase in the swelling ability of all samples by raising the pH value of the medium. Additionally, it was proved that both swelling and dehydration of the hydrogels follow non-Fickian diffusion. In vitro drug delivery experiments demonstrated that the cumulative fractional release of amoxicillin was adversely dependent on the amount of incorporated montmorillonite into the hydrogels and positively dependent on the pH of the release solution. It was also found that, in all examined samples, the mechanism by which the release of clindamycin happens is non-Fickian or anomalous transport.

Natural and Synthetic Clay Minerals in the Pharmaceutical and Biomedical Fields

Clay minerals are historically among the most used materials with a wide variety of applications. In pharmaceutical and biomedical fields, their healing properties have always been known and used in pelotherapy and therefore attractive for their potential. In recent decades, the research has therefore focused on the systematic investigation of these properties. This review aims to describe the most relevant and recent uses of clays in the pharmaceutical and biomedical field, especially for drug delivery and tissue engineering purposes. Clay minerals, which are biocompatible and non-toxic materials, can act as carriers for active ingredients while controlling their release and increasing their bioavailability. Moreover, the combination of clays and polymers is useful as it can improve the mechanical and thermal properties of polymers, as well as induce cell adhesion and proliferation. Different types of clays, both of natural (such as montmorillonite and halloysite) and synthetic origin (layered double hydroxides and zeolites), were considered in order to compare them and to assess their advantages and different uses.

Cellulose/pectin-based materials incorporating Laponite-indole derivative hybrid for oral administration and controlled delivery of the neuroprotective drug

Bionanocomposite materials based on clays have been designed for oral administration and controlled release of a neuroprotective drug derivative of 5-methylindole, which had featured an innovative pharmacological mechanism for the treatment of neurodegenerative diseases such as Alzheimer's. This drug was adsorbed in the commercially available Laponite® XLG (Lap). X-ray diffractograms confirmed its intercalation in the interlayer region of the clay. The loaded drug was 62.3 meq/100 g Lap, close to the cation exchange capacity of Lap. Per se toxicity studies and neuroprotective experiments versus the neurotoxin okadaic acid, a potent and selective inhibitor of protein phosphatase 2A (PP2A), confirmed that the clay-intercalated drug did not exert toxicity in cell cultures and provided neuroprotection. Release tests of the hybrid material performed in media mimicking the gastrointestinal tract indicated a drug release in acid medium close to 25 %. The hybrid was encapsulated in a micro/nanocellulose matrix and processed as microbeads, with pectin coating for additional protection, to minimize release under acidic conditions. Alternatively, low density materials based on a microcellulose/pectin matrix were evaluated as orodispersible foams showing fast disintegration times, sufficient mechanical resistance for handling, and release profiles in simulated media that confirmed a controlled release of the encapsulated neuroprotective drug.

Polymeric Gel Systems Cytotoxicity and Drug Release as Key Features for their Effective Application in Various Fields of Addressed Pharmaceuticals Delivery

Modified polymeric gels, including nanogels, which play not only the role of a bioinert matrix, but also perform regulatory, catalytic, and transport functions due to the active fragments introduced into them, can significantly advance the solution to the problem of targeted drug delivery in an organism. This will significantly reduce the toxicity of used pharmaceuticals and expand the range of their therapeutic, diagnostic, and medical application. This review presents a comparative description of gels based on synthetic and natural polymers intended for pharmaceutical-targeted drug delivery in the field of therapy of inflammatory and infectious diseases, dentistry, ophthalmology, oncology, dermatology, rheumatology, neurology, and the treatment of intestinal diseases. An analysis was made of most actual sources published for 2021–2022. The review is focused on the comparative characteristics of polymer gels in terms of their toxicity to cells and the release rate of drugs from nano-sized hydrogel systems, which are crucial initial features for their further possible application in mentioned areas of biomedicine. Different proposed mechanisms of drug release from gels depending on their structure, composition, and application are summarized and presented. The review may be useful for medical professionals, and pharmacologists dealing with the development of novel drug delivery vehicles.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities

Hydrogels, as interconnected networks (polymer mesh; physically, chemically, or dynamic crosslinked networks) incorporating a high amount of water, present structural characteristics similar to soft natural tissue. They enable the diffusion of different molecules (ions, drugs, and grow factors) and have the ability to take over the action of external factors. Their nature provides a wide variety of raw materials and inspiration for functional soft matter obtained by complex mechanisms and hierarchical self-assembly. Over the last decade, many studies focused on developing innovative and high-performance materials, with new or improved functions, by mimicking biological structures at different length scales. Hydrogels with natural or synthetic origin can be engineered as bulk materials, micro- or nanoparticles, patches, membranes, supramolecular pathways, bio-inks, etc. The specific features of hydrogels make them suitable for a wide variety of applications, including tissue engineering scaffolds (repair/regeneration), wound healing, drug delivery carriers, bio-inks, soft robotics, sensors, actuators, catalysis, food safety, and hygiene products. This review is focused on recent advances in the field of bioinspired hydrogels that can serve as platforms for life-science applications. A brief outlook on the actual trends and future directions is also presented.